Comparison of Percutaneous Coronary Intervention and Coronary Artery Bypass Grafting After Acute Myocardial Infarction Complicated by Cardio
http://www.100md.com
《循环学杂志》
Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand (H.D.W., J.T.S.)
Center for Statistical Analysis and Research, New England Research Institutes Inc, Watertown, Mass (S.F.A., L.A.S.)
Division of Cardiology, Evanston Northwestern Healthcare, Evanston, Ill (T.A.S.)
Division of Cardiology and Vascular Medicine, Boston Medical Centre, Boston, Mass (A.K.J.)
Division of Cardiology, St Paul’s Hospital, Vancouver, British Columbia, Canada (J.G.W.)
Department of Medical and Surgical Sciences, Otago University, Dunedin, New Zealand (C.-K.W.)
Cardiac Services, Flinders Medical Centre, Adelaide, South Australia (P.E.G.A.)
Division of Cardiology, New York Weill Cornell Medical Center, New York, NY (S.-C.W.)
Cardiovascular Clinical Research Center, New York University School of Medicine, New York, NY (J.S.H.).
Abstract
Background— The Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial demonstrated the survival advantage of emergency revascularization versus initial medical stabilization in patients developing cardiogenic shock after acute myocardial infarction. The relative merits of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) in patients with shock have not been defined. The objective of this analysis was to compare the effects of PCI and CABG on 30-day and 1-year survival in the SHOCK trial.
Methods and Results— Of the 302 trial patients, 128 with predominant left ventricular failure had emergency revascularization. The selection of revascularization procedures was individualized. Eighty-one patients (63.3%) had PCI, and 47 (36.7%) had CABG. The median time from randomization to intervention was 0.9 hours (interquartile range [IQR], 0.3 to 2.2 hours) for PCI and 2.7 hours (IQR, 1.3 to 5.5 hours) for CABG. Baseline demographics and hemodynamics were similar, except that there were more diabetics (48.9% versus 26.9%; P=0.02), 3-vessel disease (80.4% versus 60.3%; P=0.03), and left main coronary disease (41.3% versus 13.0%; P=0.001) in the CABG group. In the PCI group, 12.3% had 2-vessel and 2.5% had 3-vessel interventions. In the CABG group, 84.8% received 2 grafts, 52.2% received 3 grafts, and 87.2% were deemed completely revascularized. The survival rates were 55.6% in the PCI group compared with 57.4% in the CABG group at 30 days (P=0.86) and 51.9% compared with 46.8%, respectively, at 1 year (P=0.71).
Conclusions— Among SHOCK trial patients randomized to emergency revascularization, those treated with CABG had a greater prevalence of diabetes and worse coronary disease than those treated with PCI. However, survival rates were similar. Emergency CABG is an important component of an optimal treatment strategy in patients with cardiogenic shock, and should be considered a complementary treatment option in patients with extensive coronary disease.
Key Words: angioplasty mortality myocardial infarction shock surgery
Introduction
Cardiogenic shock is the commonest cause of death in patients with acute myocardial infarction (AMI) who reach hospital alive.1–3 In the international, multicenter Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial, 6-month survival rates were similar with emergency revascularization and initial medical stabilization, but 1-year survival rates were higher with emergency revascularization.4,5 Overall, most survivors had good quality of life.6 The protocol specified that patients randomized to emergency revascularization should have either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) within 6 hours of randomization and within 18 hours of the onset of shock. Although recommendations were made with regard to selection of revascularization procedures, this decision was made on a case-by-case basis by site investigators.
PCI and CABG are generally considered complementary treatment options for patients with chronic stable angina,7 but the relative merits and survival benefits of these procedures may differ in patients with cardiogenic shock. PCI has a lower procedural success rate in patients with shock than in those without shock, and many patients have complex 3-vessel disease that may be treated better with CABG.8–12 The benefits of CABG in patients with shock may include protection of ischemic myocardium with cardioplegia, ventricular unloading during cardiopulmonary bypass, and revascularization of noninfarct zones.
We therefore compared the demographic and survival differences of patients treated with CABG and those treated with PCI in a prespecified analysis of patients randomized to emergency revascularization in the SHOCK trial.
Methods
In the international SHOCK trial, 302 patients who developed cardiogenic shock within 36 hours of the onset of AMI were randomized to receive either emergency revascularization or initial medical stabilization. Eligible patients required either ST-segment elevation, Q-wave infarction, new left bundle-branch block, or a posterior infarct with anterior ST-segment depression on the presenting ECG. Cardiogenic shock had to be due to predominant left ventricular failure, and the trial excluded patients with isolated right ventricular infarcts and mechanical causes of shock. Shock was defined according to clinical and hemodynamic criteria including hypotension (systolic blood pressure <90 mm Hg for 30 minutes or need for supportive measures to maintain systolic blood pressure of 90 mm Hg), evidence of end-organ hypoperfusion, cardiac index of 2.2 L · min–1 · m–2, and pulmonary capillary wedge pressure of 15 mm Hg. Coronary stenosis was defined as a stenosis of 50%. PCI was considered successful if Thrombolysis in Myocardial Infarction (TIMI) grade 2 or 3 flow was achieved with 20% reduction of the treated stenosis and a residual stenosis of 50%.13 Complete revascularization with PCI was defined as successful PCI of all segments with 50% stenoses in the proximal halves of the right coronary artery, left circumflex artery, left main coronary artery, left anterior descending coronary artery, and any previous grafts. The completeness of revascularization in patients treated with CABG was judged by the surgeon at the time of surgery, and the proportion of myocardium at risk was estimated from the coronary jeopardy score.14 Intra-aortic balloon pumping was recommended for all patients. Additional details of the study design have been published previously.4
Protocol Recommendations for Revascularization Procedures
The protocol recommended that emergency PCI be performed only on the infarct-related stenosis and only in patients with 1-, 2-, or 3-vessel disease where the stenoses in 2 non–infarct-related arteries were <90% or were located in arteries supplying small branch vessels.
Patients with a left main coronary stenosis of 50%, 2 total or subtotal occlusions, stenoses of >90% in 2 non–infarct-related major arteries, or stenoses unsuitable for PCI were recommended to undergo CABG, as were patients whose PCI was unsuccessful. It was also recommended that patients with 3-vessel disease who had successful PCI of the infarct-related stenosis should be evaluated for CABG of their remaining stenoses before hospital discharge. The 7 patients who had both PCI and CABG were included in the PCI group for all analyses reported here.
Selection of Revascularization Procedures
Selection of revascularization procedures was individualized for each patient by site investigators. No data on how often the investigator’s choice matched the protocol recommendations were collected. Each site had designated and approved interventional and surgical investigators.
Statistical Analysis
Patients who were initially revascularized by PCI were compared with those initially revascularized by CABG through the use of Fisher’s exact test for categorical variables, the t test for normally distributed continuous variables, and the Wilcoxon rank-sum test for ordinal or skewed continuous variables. Logistic regression was used to generate adjusted comparisons of mortality and to assess interactions between the revascularization modality and other patient characteristics. Baseline characteristics included in the adjusted models were those that differed between treatment groups at the 0.25 significance level, ie, characteristics that were at least moderately imbalanced between the PCI and CABG groups. These included left main coronary disease, diabetes, previous AMI, infarct location, time from AMI to shock, and intra-aortic balloon pumping. Because of the high correlation between different measures of disease severity, only 1 severity measure was included at a time in each model. The Hosmer-Lemeshow test was used to assess whether any of the logistic regression models poorly fitted the data. Values of P<0.05 were considered statistically significant. SAS software (SAS Institute Inc) was used for all computations.
Results
Of the 152 patients with cardiogenic shock who were randomized to emergency revascularization, 5 did not have predominant left ventricular failure, and 5 died before cardiac catheterization. Of the remaining patients, 14 had no revascularization procedure for various reasons (Figure 1). Two of these patients died before revascularization could be attempted. Six had no significant stenoses, had TIMI grade 3 flow, or improved without revascularization; their survival rate was 83.3% at both 30 days and 1 year. Six patients had stenoses unsuitable for PCI or distal coronary arteries unsuitable for grafting; their survival rates were 33.3% at 30 days and 16.7% at 1 year.
The subsequent analyses included the 128 patients with predominant left ventricular failure who had emergency revascularization. The initial revascularization procedure was PCI in 81 patients and CABG in 47 patients (Figure 1). Ten patients (7.8%) had their revascularization procedures (1 PCI and 9 CABG) beyond the 6-hour time limit stipulated in the protocol: 5 at 6 to 8 hours and 5 at 22 hours after randomization.
The mean ages of the patients were 64.8±10.2 years in the PCI group and 65.3±9.8 years in the CABG group (P=0.75; Table 1). The other baseline demographics were also similar, except diabetes was more prevalent in the CABG group (48.9% versus 26.9% in the PCI group; P=0.02) and the infarct location differed between the 2 groups (P<0.01) in that patients in the CABG group were more likely to have AMIs that were nonanterior or noninferior.
The median time from the onset of AMI to revascularization was shorter in patients treated with PCI (11.0 hours; interquartile range [IQR], 6.1 to 21.4 hours) than in those treated with CABG (19.1 hours; IQR, 10.4 to 30.5 hours; P<0.001; Table 2). The median time from randomization to PCI was 0.9 hours (IQR, 0.3 to 2.2 hours), and the median time to CABG was 2.7 hours (IQR, 1.3 to 5.5 hours; P<0.0001). Hemodynamics at the time of randomization, which were often measured while the patients were on inotropes and/or intra-aortic balloon pumps, were similar in the 2 groups.
Seven patients in the PCI group had CABG after their initial PCI (6 after successful PCI and 1 after unsuccessful PCI). In 6 of the 7, CABG was performed within 24 hours of the onset of shock (within 18 hours in 5 and at 19 hours in 1). In 3 of the 6 PCI patients who subsequently had emergency CABG, it was done as a planned, staged procedure after successful PCI on the infarct-related stenosis. The remaining patient had delayed CABG 15 days after the onset of shock.
Coronary Anatomy and Details of Revascularization Procedures
In the PCI group, 69 patients (85.2%) had PCI only on the infarct-related stenosis (Table 4). PCI was successful in 77.2% of patients, and complete revascularization was achieved in 23.1%. Stents were used in 30 patients (37.0%), and their use increased over time from 0% at the start of the trial to 74.3% in 1997 to 1998. Overall, the use of adjunctive glycoprotein IIb/IIIa inhibitors was low, with 0 being used at the start of the trial and abciximab being used in 71.9% of patients treated in the last 2 years of the trial. Of the 36 patients with 3-vessel disease who had successful PCI on the infarct-related stenosis, 3 patients subsequently had CABG within 24 hours.
The details of CABG are shown in Table 5. Cardioplegia was used in 86.1% of the 36 patients who had CABG after institution of a cardiac surgery data collection form partway through the trial. The mean number of grafts inserted during CABG was 2.7±1.1. Left internal mammary arterial grafts were used in 15.2% of patients. Complete revascularization was achieved in 87.2% of patients, and concomitant valve procedures were performed in 5.6%. CABG was performed in similar percentages of patients randomized between midnight and 7:59 AM (31%), between 8 AM and 3:59 PM (38%), and between 4 PM and 11:59 PM (37%; P=0.90).
Survival
The vital status of all patients was ascertained at 1 year. The 96-hour survival rates were 65.4% in the PCI group and 80.9% in the CABG group (P=0.07; Table 6 and Figure 2). Both groups had similar survival rates at 30 days (55.6% with PCI versus 57.4% with CABG; P=0.86) and at 1 year (51.9% versus 46.8%, respectively; P=0.71; Figure 2), and there were no differences in 30-day or 1-year survival in any subgroup (Table 7). There was no indication that the association between the revascularization modality and 1-year mortality changed over the duration of the study (1993 to 1994, 1995 to 1996, 1997 to 1998; P=0.69).
Severity of Coronary Disease, Revascularization Modality, and Survival
There was no association between the revascularization modality and survival in any category of disease severity (Table 7). Of 29 patients with left main coronary disease, 10 had PCI and 19 had CABG; their 1-year survival rates were 30.0% and 47.4%, respectively (P=0.45). Of 56 patients with 3-vessel disease but no left main coronary disease, 37 had PCI and 19 had CABG; their 1-year survival rates were 51.4% and 47.4%, respectively (P=1.00). Of 39 patients with 1- or 2-vessel disease but no left main coronary disease, 31 had PCI and 8 had CABG; their 1-year survival rates were 61.3% and 50.0%, respectively (P=0.69).
Three patients had PCI for a left main coronary stenosis. Two died within 96 hours, and 1 was still alive at 1 year.
Success of PCI and Survival
Patients who had successful PCI had higher survival rates at 30 days (63.9% versus 22.2%; P<0.01) and at 1 year (60.7% versus 22.2%; P<0.01) than those who had unsuccessful PCI. The 30-day survival rates were 60.0% in patients who had any stenosis stented versus 52.9% in patients receiving no stents (P=0.64), and the 1-year survival rates were 56.7% versus 49.0%, respectively (P=0.65). Patients with complete revascularization had survival rates of 66.7% at 30 days and 61.1% at 1 year versus 51.7% at 30 days (P=0.29) and 50.0% at 1 year (P=0.43) in patients with incomplete revascularization.
Success of CABG and Survival
CABG achieved complete revascularization in 41 patients (87.2%) and incomplete revascularization in 6 patients (12.8%). The survival rates were 63.4% versus 16.7%, respectively, at 30 days (P=0.07) and 51.2% versus 16.7%, respectively, at 1 year (P=0.19).
Age, Revascularization Modality, and Survival
Among patients <75 years of age, there was no difference in 1-year survival between those treated with PCI and those treated with CABG (56.3% versus 46.3%, respectively; P=0.33; Table 7). Sixteen patients 75 years of age had emergency revascularization, 10 by PCI and 6 by CABG; their 1-year survival rates were 20.0% and 50.0%, respectively (P=0.30).
Multipredictor Model for Survival
Adjusted mortality models showed that there was no difference in 30-day or 1-year survival between patients treated with PCI and those treated with CABG (Table 8). There was no significant interaction between the revascularization modality (PCI versus CABG) and the presence of left main coronary disease. Results were similar when other measures of disease severity (3-vessel disease, left main and/or 3-vessel disease, or coronary jeopardy score) were substituted for left main disease in these models (data not shown). In the adjusted 30-day mortality model, the area under the curve was 0.675, and the likelihood ratio probability value for the whole model was 0.096. In the adjusted 1-year mortality model, the area under the curve was 0.645, and the likelihood ratio probability value for the whole model was 0.242.
Discussion
The findings of this study suggest that PCI and CABG are complementary treatment options for emergency revascularization in patients with cardiogenic shock. Although patients treated with CABG had more extensive and more severe coronary disease than patients treated with PCI, they had similar survival rates at 30 days and 1 year, perhaps because CABG achieved complete revascularization in a greater proportion of patients than PCI did. It is interesting that there was a trend for 96-hour survival to be higher with CABG. This may have been related to the level of care provided in a surgical intensive care unit.
Despite the protocol recommendations with regard to selection of revascularization procedures, this analysis was not limited by those recommendations because many patients with 3-vessel disease had PCI. However, the analysis was probably confounded because patients with 3-vessel disease who were treated with PCI had less severe coronary disease than those who were treated with CABG. In an emergency situation such as cardiogenic shock, investigators may have opted for emergency PCI on stenoses not ideally suited to PCI, knowing that although CABG might achieve more complete revascularization, PCI could be performed more promptly. PCI may also have been performed on patients with poor distal vessels. In addition, the further delay in reperfusion by CABG may suggest that more stable patients were referred for CABG and that very unstable patients were referred for PCI. However, this concept is not supported by the hemodynamic data, which were similar in PCI and CABG patients at baseline.
Diabetes was more prevalent in patients treated with CABG than in those treated with PCI. The investigators’ preference for CABG in diabetic patients may have been influenced by the findings of the Bypass Angioplasty Revascularization Investigation (BARI),15 in which diabetic patients with multivessel disease fared better after CABG than after PCI. However, BARI predated the widespread use of stenting and glycoprotein IIb/IIIa inhibitors, and a 7-year follow-up of the BARI registry, in which the revascularization modality was selected by the attending clinician, showed that diabetic patients had similar survival rates regardless of whether they were treated with PCI or CABG.16 In the present study, the outcome of diabetic patients was not predicted by the revascularization modality. Restenosis has been shown to be a powerful predictor of long-term mortality in diabetics,17 and new stenting technologies such as drug-eluting stents are likely to improve the outcome of diabetic patients by reducing restenosis.18
In the current European Society of Cardiology/American College of Cardiology guidelines,19 AMI with cardiogenic shock is listed as a class IA indication (ie, a condition for which there is evidence for and/or general agreement that a given procedure/treatment is useful and effective) for PCI and a class IA indication for CABG if the patient has suitable coronary anatomy. However, emergency CABG is not widely considered an integral part of contemporary management of patients with cardiogenic shock. In the SHOCK trial,4 which provided the evidence base for the guideline recommendations, 36.7% of patients with left ventricular failure who were assigned to emergency revascularization had CABG as their initial revascularization procedure. Recent data from the National Registry of Myocardial Infarction indicate that CABG is underused in patients with cardiogenic shock, with only 4.9% having early CABG in 2001.20 This underuse may reflect the logistical difficulties of arranging emergency CABG for patients with cardiogenic shock, especially at night or during weekends.
Findings from the SHOCK trial registry showed that revascularization was associated with lower in-hospital mortality in patients with cardiogenic shock.21 In this registry of 884 patients with predominant left ventricular pump failure, 276 (31.2%) had PCI and 109 (12.3%) had CABG. The in-hospital mortality rates were 78.0% in patients treated medically, 46.4% in those treated with PCI, and 23.9% in those treated with CABG (P<0.001). Patients with single-vessel disease had similar in-hospital mortality rates regardless of whether they were treated with PCI or CABG (32.9% versus 33.3%). Patients with 2-vessel disease had higher in-hospital mortality with PCI than with CABG (42.2% versus 17.7%; P=0.025), as did patients with 3-vessel disease (59.35% versus 29.6%; P<0.0001).
Unlike the SHOCK trial, the SHOCK trial registry was nonrandomized, and patients who had diagnostic angiography had more favorable hemodynamic findings than those who did not have angiography, resulting in a selected population.22 No other randomized trials comparing revascularization with medical treatment in patients with cardiogenic shock have included CABG as part of the initial revascularization strategy. The Swiss Multicenter Trial of Angioplasty for Shock (SMASH)23 was terminated early for logistical reasons after 55 patients had been randomized to receive either PCI or medical treatment, and CABG was performed in only 1 patient.
The SHOCK trial protocol recommended PCI only for the infarct-related stenosis, and only 13.6% of patients had emergency PCI on >1 vessel. Given concerns about the possibility of continuing ischemia in other territories and the higher procedural success rates now achieved with more frequent use of stenting and glycoprotein IIb/IIIa inhibitors, it may be appropriate to also treat additional stenoses during the index procedure.24 However, PCI of non–infarct-related stenoses may cause deterioration in coronary flow as a result of embolization of plaque or compromise of side branches in both the infarct and noninfarct zones, thereby impairing collateral blood supply to the infarct zone. In the SHOCK trial, multivessel PCI was associated with a worse outcome than single-vessel PCI.12 This finding may have been confounded by a treatment selection bias in that some patients had PCI rather than CABG because they were considered poor surgical candidates for various reasons.
The procedural success rate of 77.2% in patients who had emergency PCI12 is similar to rates observed in other studies of patients with cardiogenic shock.8,11 Although there have been many advances in PCI (including stenting,12 which reduces reintervention rates, and adjunctive use of glycoprotein IIb/IIIa inhibitors),25–28 patients with cardiogenic shock still have a lower likelihood of successful PCI than patients without shock.4,8–11 For example, a recent German registry study of 1333 patients with cardiogenic shock reported that PCI achieved TIMI 3 flow in only 75.2% of patients.29 In another study of 369 patients with ST-elevation AMI (including 23 patients with cardiogenic shock), drug-eluting stents were compared with bare metal stents and resulted in similar postprocedural vessel patency rates and 30-day complication rates. Patients receiving drug-eluting stents had no increase in stent thrombosis and were less likely to require reintervention within 300 days of follow-up.30
In the SHOCK trial, only 37% of patients received stents, and only 69% received abciximab. A prospective registry study of patients having PCI for cardiogenic shock at the Cleveland Clinic27 showed that stenting increased the likelihood of TIMI grade 3 flow and that adjunctive use of abciximab with stenting increased the survival rate at 1 year.27 In the Abciximab Before Direct Angioplasty and Stenting in Myocardial Infarction Regarding Acute and Long-Term Follow-Up (ADMIRAL) study,31 25 patients presented with cardiogenic shock. Those given adjunctive abciximab before stenting tended to have a lower 6-month event rate (death, AMI, or urgent target-vessel revascularization) than those given a placebo (9.1% versus 28.6%; P=0.23). In the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial of eptifibatide in patients with non–ST-segment elevation acute coronary syndromes, 237 patients developed cardiogenic shock after enrollment. Those given eptifibatide had a lower 30-day mortality rate than those given a placebo (adjusted odds ratio, 0.51; 95% CI, 0.28 to 0.94).28
In the SHOCK trial, 84.8% of patients treated with CABG received >1 graft. Left internal mammary arterial grafts were used in 15.2% of patients. In 87.2% of patients, the surgeons judged that complete revascularization had been achieved. Greater use of arterial grafts and advances in cardioplegia and anesthesia might produce even better results than those observed in this trial.
This analysis had a number of limitations, including the nonrandomized nature of the study and the small number of patients in each treatment group. The treatment strategies used and the time to treatment (particularly in the CABG group) may not be representative of contemporary practice. In addition, multivessel PCI was performed infrequently, and the degree of revascularization achieved was less than that currently recommended.24,32 It is not yet known whether a strategy of acute stenting of the culprit vessel in AMI with subsequent elective treatment of nonculprit stenoses is preferable to complete revascularization in the acute phase. The next logical step would be to perform a randomized comparison of emergency CABG and emergency PCI in patients with cardiogenic shock, including liberal use of drug-eluting stents and glycoprotein IIb/IIIa inhibitors.
Conclusions
Among patients randomized to emergency revascularization in the SHOCK trial, those selected for CABG were more likely to have diabetes and to have more severe coronary disease than those selected for PCI. Despite this disparity in risk factors between the 2 groups, the survival rates at 30 days and 1 year were similar. In cases in which PCI is unlikely to achieve complete revascularization or there are associated mechanical complications or left main or severe 3-vessel coronary disease, CABG should be performed. Emergency CABG is an important component of an early invasive strategy in patients with cardiogenic shock.
Acknowledgments
This work was supported by grants R01-HL-0020-018Z and HL-49970 from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md. Professor White received partial salary funding from the Green Lane Research and Educational Fund Board (Auckland, New Zealand). We gratefully acknowledge the patients and investigators who participated in the SHOCK trial. We also thank Charlene Nell and Barbara Semb for secretarial assistance and Anna Breckon, ELS, for editorial assistance.
Footnotes
Guest Editor for this article was Robert O. Bonow, MD.
References
Hands ME, Rutherford JD, Muller JE, Davies G, Stone PH, Parker C, Braunwald E. The in-hospital development of cardiogenic shock after myocardial infarction: incidence, predictors of occurrence, outcome and prognostic factors. J Am Coll Cardiol. 1989; 14: 40–46.
Holmes DR Jr, Bates ER, Kleiman NS, Sadowski Z, Horgan JH, Morris DC, Califf RM, Berger PB, Topol EJ. Contemporary reperfusion therapy for cardiogenic shock: the GUSTO-I trial experience: the GUSTO-I Investigators: Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries. J Am Coll Cardiol. 1995; 26: 668–674.
Goldberg RJ, Samad NA, Yarzebski J, Gurwitz J, Bigelow C, Gore JM. Temporal trends in cardiogenic shock complicating acute myocardial infarction. N Engl J Med. 1999; 340: 1162–1168.
Hochman JS, Sleeper LA, Webb JG, Sanborn TA, White HD, Talley JD, Buller CE, Jacobs AK, Slater JN, Col J, McKinlay SM, LeJemtel TH, Picard MH, Menegus MA, Boland J, Dzavik V, Thompson CR, Wong SC, Steingart R, Forman R, Aylward PE, Godfrey E, Desvigne-Nickens P, for the SHOCK Investigators. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. N Engl J Med. 1999; 341: 625–634.
Hochman JS, Sleeper LA, White HD, Dzavik V, Wong SC, Menon V, Webb JG, Steingart R, Picard MH, Menegus MA, Boland J, Sanborn T, Buller CE, Modur S, Forman R, Desvigne-Nickens P, Jacobs AK, Slater JN, LeJemtel TH. One-year survival following early revascularization for cardiogenic shock. JAMA. 2001; 285: 190–192.
Sleeper LA, Ramanathan K, Picard MH, LeJerntel TH, White HD, Dzavik V, Tormey D, Avis NE, Hochman JS. Functional status and quality of life after emergency revascularization for cardiogenic shock complicating acute myocardial infarction. J Am Coll Cardiol. 2005; 46: 266–273.
White HD. Angioplasty versus bypass surgery. Lancet. 1995; 346: 1174–1175.Commentary.
Antoniucci D, Valenti R, Santoro GM, Bolognese L, Trapani M, Moschi G, Fazzini PF. Systematic direct angioplasty and stent-supported direct angioplasty therapy for cardiogenic shock complicating acute myocardial infarction: in-hospital and long-term survival. J Am Coll Cardiol. 1998; 31: 294–300.
Moosvi AR, Khaja F, Villanueva L, Gheorghiade M, Douthat L, Goldstein S. Early revascularization improves survival in cardiogenic shock complicating acute myocardial infarction. J Am Coll Cardiol. 1992; 19: 907–914.
Hibbard MD, Holmes DR Jr, Bailey KR, Reeder GS, Bresnahan JF, Gersh BJ. Percutaneous transluminal coronary angioplasty in patients with cardiogenic shock. J Am Coll Cardiol. 1992; 19: 639–646.
Gacioch GM, Ellis SG, Lee L, Bates ER, Kirsh M, Walton JA, Topol EJ. Cardiogenic shock complicating acute myocardial infarction: the use of coronary angioplasty and the integration of the new support devices into patient management. J Am Coll Cardiol. 1992; 19: 647–653.
Webb JG, Lowe AM, Sanborn TA, White HD, Sleeper LA, Carere RG, Buller CE, Wong SC, Boland J, Dzavik V, Porway M, Pate G, Bergman G, Hochman JS, for the SHOCK Investigators. Percutaneous coronary intervention for cardiogenic shock in the SHOCK trial. J Am Coll Cardiol. 2003; 42: 1380–1386.
TIMI Study Group. Comparison of invasive and conservative strategies after treatment with intravenous tissue plasminogen activator in acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) Phase II trial. N Engl J Med. 1989; 320: 618–627.
Califf RM, Phillips HRI, Hindman MC, Mark DB, Lee KL, Behar VS, Johnson RA, Pryor DB, Rosati RA, Wagner GS. Prognostic value of a coronary artery jeopardy score. J Am Coll Cardiol. 1985; 5: 1055–1063.
Bypass Angioplasty Revascularization Investigation (BARI) Investigators. Comparison of coronary bypass surgery with angioplasty in patients with multivessel disease. N Engl J Med. 1996; 335: 217–225.
Feit F, Brooks MM, Sopko G, Keller NM, Rosen A, Krone R, Berger PB, Shemin R, Attubato MJ, Williams DO, Frye R, Detre KM. Long-term clinical outcome in the Bypass Angioplasty Revascularization Investigation Registry: comparison with the randomized trial: BARI Investigators. Circulation. 2000; 101: 2795–2802.
Van Belle E, Ketelers R, Bauters C, Perie M, Abolmaali K, Richard F, LaBlanche JM, McFadden EP, Bertrand ME. Patency of percutaneous transluminal coronary angioplasty sites at 6-month angiographic follow-up: a key determinant of survival in diabetics after coronary balloon angioplasty. Circulation. 2001; 103: 1218–1224.
Morice MC, Serruys PW, Sousa JE, Fajadet J, Ban Hayashi E, Perin M, Colombo A, Schuler G, Barragan P, Guagliumi G, Molnar F, Falotico R. A randomized comparison of a sirolimus-eluting stent with a standard stent for coronary revascularization. N Engl J Med. 2002; 346: 1773–1780.
Antman EM, Anbe DT, Armstrong PW, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr, Alpert JS, Anderson JL, Faxon DP, Fuster V, Gibbons RJ, Gregoratos G, Halperin JL, Hiratzka LF, Hunt SA, Jacobs AK. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1999 Guidelines for the Management of Patients With Acute Myocardial Infarction). Circulation. 2004; 110: 588–636.
Babaev A, Every N, Frederick P, Sichrovsky T, Hochman JS. Trends in revascularization and mortality in patients with cardiogenic shock complicating acute myocardial infarction: observations from the National Registry of Myocardial Infarction. Circulation. 2002; 106 (suppl II): II-364.Abstract.
Webb JG, Sanborn TA, Sleeper LA, Carere RG, Buller CE, Slater JN, Baran KW, Koller PT, Talley JD, Porway M, Hochman JS. Percutaneous coronary intervention for cardiogenic shock in the SHOCK trial registry. Am Heart J. 2001; 141: 964–970.
Wong SC, Sleeper LA, Monrad ES, Menegus MA, Palazzo A, Dzavik V, Jacobs A, Jiang X, Hochman JS. Absence of gender differences in clinical outcomes in patients with cardiogenic shock complicating acute myocardial infarction: a report from the SHOCK trial registry. J Am Coll Cardiol. 2001; 38: 1395–1401.
Urban P, Stauffer JC, Bleed D, Khatchatrian N, Amann W, Bertel O, van den Brand M, Danchin N, Kauffmann U, Meier B, Machecourt J, Pfisterer M, for the (S)MASH Investigators. A randomized evaluation of early revascularization to treat shock complicating acute myocardial infarction: the (Swiss) Multicenter Trial of Angioplasty for Shock—(S)MASH. Eur Heart J. 1999; 20: 1030–1038.
Montalescot G, Andersen HR, Antoniucci D, Betriu A, de Boer MJ, Grip L, Neumann FJ, Rothman MT. Recommendations on percutaneous coronary intervention for the reperfusion of acute ST elevation myocardial infarction. Heart. 2004; 90: e37.
Stone GW, Grines CL, Cox DA, Garcia E, Tcheng JE, Griffin JJ, Guagliumi G, Stuckey T, Turco M, Carroll JD, Rutherford BD, Lansky AJ, for the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) Investigators. Comparison of angioplasty with stenting, with or without abciximab, in acute myocardial infarction. N Engl J Med. 2002; 346: 957–966.
Giri S, Mitchel J, Azar RR, Kiernan FJ, Fram DB, McKay RG, Mennett R, Clive J, Hirst JA. Results of primary percutaneous transluminal coronary angioplasty plus abciximab with or without stenting for acute myocardial infarction complicated by cardiogenic shock. Am J Cardiol. 2002; 89: 126–131.
Chan AW, Chew DP, Bhatt DL, Moliterno DJ, Topol EJ, Ellis SG. Long-term mortality benefit with the combination of stents and abciximab for cardiogenic shock complicating acute myocardial infarction. Am J Cardiol. 2002; 89: 132–136.
Hasdai D, Harrington RA, Hochman JS, Califf RM, Battler A, Box JW, Simoons ML, Deckers J, Topol EJ, Holmes DR Jr. Platelet glycoprotein IIb/IIIa blockade and outcome of cardiogenic shock complicating acute coronary syndromes without persistent ST-segment elevation. J Am Coll Cardiol. 2000; 36: 685–692.
Zeymer U, Vogt A, Zahn R, Weber MA, Tebbe U, Gottwik M, Bonzel T, Senges J, Neuhaus KL, for the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausrtze (ALKK). Predictors of in-hospital mortality in 1333 patients with acute myocardial infarction complicated by cardiogenic shock treated with primary percutaneous coronary intervention (PCI): results of the primary PCI registry of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausrtze (ALKK). Eur Heart J. 2004; 25: 322–328.
Lemos PA, Saia F, Hofma SH, Daemen J, Ong AT, Arampatzis CA, Hoye A, McFadden E, Sianos G, Smits PC, van der Giessen WJ, de Feyter P, van Domburg RT, Serruys PW. Short- and long-term clinical benefit of sirolimus-eluting stents compared to conventional bare stents for patients with acute myocardial infarction. J Am Coll Cardiol. 2004; 43: 704–708.
Montalescot G, Barragan P, Wittenberg O, Elhadad S, Lefevre T, Loubeyre C, Lafont A, Zupan M, Paganelli F, Pinton P. Primary stenting with abciximab in acute myocardial infarction complicated by cardiogenic shock (the ADMIRAL trial). J Am Coll Cardiol. 2002; 39 (suppl A): 43A.Abstract.
Silber S, Albertsson P, Aviles FF, Camici PG, Colombo A, Hamm C, Jorgensen E, Marco J, Nordrehaug JE, Ruzyllo W, Urban P, Stone GW, Wijns W. Guidelines for percutaneous coronary interventions: the Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology. Eur Heart J. 2005; 26: 804–847.(Harvey D. White, DSc, FCS)
Center for Statistical Analysis and Research, New England Research Institutes Inc, Watertown, Mass (S.F.A., L.A.S.)
Division of Cardiology, Evanston Northwestern Healthcare, Evanston, Ill (T.A.S.)
Division of Cardiology and Vascular Medicine, Boston Medical Centre, Boston, Mass (A.K.J.)
Division of Cardiology, St Paul’s Hospital, Vancouver, British Columbia, Canada (J.G.W.)
Department of Medical and Surgical Sciences, Otago University, Dunedin, New Zealand (C.-K.W.)
Cardiac Services, Flinders Medical Centre, Adelaide, South Australia (P.E.G.A.)
Division of Cardiology, New York Weill Cornell Medical Center, New York, NY (S.-C.W.)
Cardiovascular Clinical Research Center, New York University School of Medicine, New York, NY (J.S.H.).
Abstract
Background— The Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial demonstrated the survival advantage of emergency revascularization versus initial medical stabilization in patients developing cardiogenic shock after acute myocardial infarction. The relative merits of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) in patients with shock have not been defined. The objective of this analysis was to compare the effects of PCI and CABG on 30-day and 1-year survival in the SHOCK trial.
Methods and Results— Of the 302 trial patients, 128 with predominant left ventricular failure had emergency revascularization. The selection of revascularization procedures was individualized. Eighty-one patients (63.3%) had PCI, and 47 (36.7%) had CABG. The median time from randomization to intervention was 0.9 hours (interquartile range [IQR], 0.3 to 2.2 hours) for PCI and 2.7 hours (IQR, 1.3 to 5.5 hours) for CABG. Baseline demographics and hemodynamics were similar, except that there were more diabetics (48.9% versus 26.9%; P=0.02), 3-vessel disease (80.4% versus 60.3%; P=0.03), and left main coronary disease (41.3% versus 13.0%; P=0.001) in the CABG group. In the PCI group, 12.3% had 2-vessel and 2.5% had 3-vessel interventions. In the CABG group, 84.8% received 2 grafts, 52.2% received 3 grafts, and 87.2% were deemed completely revascularized. The survival rates were 55.6% in the PCI group compared with 57.4% in the CABG group at 30 days (P=0.86) and 51.9% compared with 46.8%, respectively, at 1 year (P=0.71).
Conclusions— Among SHOCK trial patients randomized to emergency revascularization, those treated with CABG had a greater prevalence of diabetes and worse coronary disease than those treated with PCI. However, survival rates were similar. Emergency CABG is an important component of an optimal treatment strategy in patients with cardiogenic shock, and should be considered a complementary treatment option in patients with extensive coronary disease.
Key Words: angioplasty mortality myocardial infarction shock surgery
Introduction
Cardiogenic shock is the commonest cause of death in patients with acute myocardial infarction (AMI) who reach hospital alive.1–3 In the international, multicenter Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial, 6-month survival rates were similar with emergency revascularization and initial medical stabilization, but 1-year survival rates were higher with emergency revascularization.4,5 Overall, most survivors had good quality of life.6 The protocol specified that patients randomized to emergency revascularization should have either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) within 6 hours of randomization and within 18 hours of the onset of shock. Although recommendations were made with regard to selection of revascularization procedures, this decision was made on a case-by-case basis by site investigators.
PCI and CABG are generally considered complementary treatment options for patients with chronic stable angina,7 but the relative merits and survival benefits of these procedures may differ in patients with cardiogenic shock. PCI has a lower procedural success rate in patients with shock than in those without shock, and many patients have complex 3-vessel disease that may be treated better with CABG.8–12 The benefits of CABG in patients with shock may include protection of ischemic myocardium with cardioplegia, ventricular unloading during cardiopulmonary bypass, and revascularization of noninfarct zones.
We therefore compared the demographic and survival differences of patients treated with CABG and those treated with PCI in a prespecified analysis of patients randomized to emergency revascularization in the SHOCK trial.
Methods
In the international SHOCK trial, 302 patients who developed cardiogenic shock within 36 hours of the onset of AMI were randomized to receive either emergency revascularization or initial medical stabilization. Eligible patients required either ST-segment elevation, Q-wave infarction, new left bundle-branch block, or a posterior infarct with anterior ST-segment depression on the presenting ECG. Cardiogenic shock had to be due to predominant left ventricular failure, and the trial excluded patients with isolated right ventricular infarcts and mechanical causes of shock. Shock was defined according to clinical and hemodynamic criteria including hypotension (systolic blood pressure <90 mm Hg for 30 minutes or need for supportive measures to maintain systolic blood pressure of 90 mm Hg), evidence of end-organ hypoperfusion, cardiac index of 2.2 L · min–1 · m–2, and pulmonary capillary wedge pressure of 15 mm Hg. Coronary stenosis was defined as a stenosis of 50%. PCI was considered successful if Thrombolysis in Myocardial Infarction (TIMI) grade 2 or 3 flow was achieved with 20% reduction of the treated stenosis and a residual stenosis of 50%.13 Complete revascularization with PCI was defined as successful PCI of all segments with 50% stenoses in the proximal halves of the right coronary artery, left circumflex artery, left main coronary artery, left anterior descending coronary artery, and any previous grafts. The completeness of revascularization in patients treated with CABG was judged by the surgeon at the time of surgery, and the proportion of myocardium at risk was estimated from the coronary jeopardy score.14 Intra-aortic balloon pumping was recommended for all patients. Additional details of the study design have been published previously.4
Protocol Recommendations for Revascularization Procedures
The protocol recommended that emergency PCI be performed only on the infarct-related stenosis and only in patients with 1-, 2-, or 3-vessel disease where the stenoses in 2 non–infarct-related arteries were <90% or were located in arteries supplying small branch vessels.
Patients with a left main coronary stenosis of 50%, 2 total or subtotal occlusions, stenoses of >90% in 2 non–infarct-related major arteries, or stenoses unsuitable for PCI were recommended to undergo CABG, as were patients whose PCI was unsuccessful. It was also recommended that patients with 3-vessel disease who had successful PCI of the infarct-related stenosis should be evaluated for CABG of their remaining stenoses before hospital discharge. The 7 patients who had both PCI and CABG were included in the PCI group for all analyses reported here.
Selection of Revascularization Procedures
Selection of revascularization procedures was individualized for each patient by site investigators. No data on how often the investigator’s choice matched the protocol recommendations were collected. Each site had designated and approved interventional and surgical investigators.
Statistical Analysis
Patients who were initially revascularized by PCI were compared with those initially revascularized by CABG through the use of Fisher’s exact test for categorical variables, the t test for normally distributed continuous variables, and the Wilcoxon rank-sum test for ordinal or skewed continuous variables. Logistic regression was used to generate adjusted comparisons of mortality and to assess interactions between the revascularization modality and other patient characteristics. Baseline characteristics included in the adjusted models were those that differed between treatment groups at the 0.25 significance level, ie, characteristics that were at least moderately imbalanced between the PCI and CABG groups. These included left main coronary disease, diabetes, previous AMI, infarct location, time from AMI to shock, and intra-aortic balloon pumping. Because of the high correlation between different measures of disease severity, only 1 severity measure was included at a time in each model. The Hosmer-Lemeshow test was used to assess whether any of the logistic regression models poorly fitted the data. Values of P<0.05 were considered statistically significant. SAS software (SAS Institute Inc) was used for all computations.
Results
Of the 152 patients with cardiogenic shock who were randomized to emergency revascularization, 5 did not have predominant left ventricular failure, and 5 died before cardiac catheterization. Of the remaining patients, 14 had no revascularization procedure for various reasons (Figure 1). Two of these patients died before revascularization could be attempted. Six had no significant stenoses, had TIMI grade 3 flow, or improved without revascularization; their survival rate was 83.3% at both 30 days and 1 year. Six patients had stenoses unsuitable for PCI or distal coronary arteries unsuitable for grafting; their survival rates were 33.3% at 30 days and 16.7% at 1 year.
The subsequent analyses included the 128 patients with predominant left ventricular failure who had emergency revascularization. The initial revascularization procedure was PCI in 81 patients and CABG in 47 patients (Figure 1). Ten patients (7.8%) had their revascularization procedures (1 PCI and 9 CABG) beyond the 6-hour time limit stipulated in the protocol: 5 at 6 to 8 hours and 5 at 22 hours after randomization.
The mean ages of the patients were 64.8±10.2 years in the PCI group and 65.3±9.8 years in the CABG group (P=0.75; Table 1). The other baseline demographics were also similar, except diabetes was more prevalent in the CABG group (48.9% versus 26.9% in the PCI group; P=0.02) and the infarct location differed between the 2 groups (P<0.01) in that patients in the CABG group were more likely to have AMIs that were nonanterior or noninferior.
The median time from the onset of AMI to revascularization was shorter in patients treated with PCI (11.0 hours; interquartile range [IQR], 6.1 to 21.4 hours) than in those treated with CABG (19.1 hours; IQR, 10.4 to 30.5 hours; P<0.001; Table 2). The median time from randomization to PCI was 0.9 hours (IQR, 0.3 to 2.2 hours), and the median time to CABG was 2.7 hours (IQR, 1.3 to 5.5 hours; P<0.0001). Hemodynamics at the time of randomization, which were often measured while the patients were on inotropes and/or intra-aortic balloon pumps, were similar in the 2 groups.
Seven patients in the PCI group had CABG after their initial PCI (6 after successful PCI and 1 after unsuccessful PCI). In 6 of the 7, CABG was performed within 24 hours of the onset of shock (within 18 hours in 5 and at 19 hours in 1). In 3 of the 6 PCI patients who subsequently had emergency CABG, it was done as a planned, staged procedure after successful PCI on the infarct-related stenosis. The remaining patient had delayed CABG 15 days after the onset of shock.
Coronary Anatomy and Details of Revascularization Procedures
In the PCI group, 69 patients (85.2%) had PCI only on the infarct-related stenosis (Table 4). PCI was successful in 77.2% of patients, and complete revascularization was achieved in 23.1%. Stents were used in 30 patients (37.0%), and their use increased over time from 0% at the start of the trial to 74.3% in 1997 to 1998. Overall, the use of adjunctive glycoprotein IIb/IIIa inhibitors was low, with 0 being used at the start of the trial and abciximab being used in 71.9% of patients treated in the last 2 years of the trial. Of the 36 patients with 3-vessel disease who had successful PCI on the infarct-related stenosis, 3 patients subsequently had CABG within 24 hours.
The details of CABG are shown in Table 5. Cardioplegia was used in 86.1% of the 36 patients who had CABG after institution of a cardiac surgery data collection form partway through the trial. The mean number of grafts inserted during CABG was 2.7±1.1. Left internal mammary arterial grafts were used in 15.2% of patients. Complete revascularization was achieved in 87.2% of patients, and concomitant valve procedures were performed in 5.6%. CABG was performed in similar percentages of patients randomized between midnight and 7:59 AM (31%), between 8 AM and 3:59 PM (38%), and between 4 PM and 11:59 PM (37%; P=0.90).
Survival
The vital status of all patients was ascertained at 1 year. The 96-hour survival rates were 65.4% in the PCI group and 80.9% in the CABG group (P=0.07; Table 6 and Figure 2). Both groups had similar survival rates at 30 days (55.6% with PCI versus 57.4% with CABG; P=0.86) and at 1 year (51.9% versus 46.8%, respectively; P=0.71; Figure 2), and there were no differences in 30-day or 1-year survival in any subgroup (Table 7). There was no indication that the association between the revascularization modality and 1-year mortality changed over the duration of the study (1993 to 1994, 1995 to 1996, 1997 to 1998; P=0.69).
Severity of Coronary Disease, Revascularization Modality, and Survival
There was no association between the revascularization modality and survival in any category of disease severity (Table 7). Of 29 patients with left main coronary disease, 10 had PCI and 19 had CABG; their 1-year survival rates were 30.0% and 47.4%, respectively (P=0.45). Of 56 patients with 3-vessel disease but no left main coronary disease, 37 had PCI and 19 had CABG; their 1-year survival rates were 51.4% and 47.4%, respectively (P=1.00). Of 39 patients with 1- or 2-vessel disease but no left main coronary disease, 31 had PCI and 8 had CABG; their 1-year survival rates were 61.3% and 50.0%, respectively (P=0.69).
Three patients had PCI for a left main coronary stenosis. Two died within 96 hours, and 1 was still alive at 1 year.
Success of PCI and Survival
Patients who had successful PCI had higher survival rates at 30 days (63.9% versus 22.2%; P<0.01) and at 1 year (60.7% versus 22.2%; P<0.01) than those who had unsuccessful PCI. The 30-day survival rates were 60.0% in patients who had any stenosis stented versus 52.9% in patients receiving no stents (P=0.64), and the 1-year survival rates were 56.7% versus 49.0%, respectively (P=0.65). Patients with complete revascularization had survival rates of 66.7% at 30 days and 61.1% at 1 year versus 51.7% at 30 days (P=0.29) and 50.0% at 1 year (P=0.43) in patients with incomplete revascularization.
Success of CABG and Survival
CABG achieved complete revascularization in 41 patients (87.2%) and incomplete revascularization in 6 patients (12.8%). The survival rates were 63.4% versus 16.7%, respectively, at 30 days (P=0.07) and 51.2% versus 16.7%, respectively, at 1 year (P=0.19).
Age, Revascularization Modality, and Survival
Among patients <75 years of age, there was no difference in 1-year survival between those treated with PCI and those treated with CABG (56.3% versus 46.3%, respectively; P=0.33; Table 7). Sixteen patients 75 years of age had emergency revascularization, 10 by PCI and 6 by CABG; their 1-year survival rates were 20.0% and 50.0%, respectively (P=0.30).
Multipredictor Model for Survival
Adjusted mortality models showed that there was no difference in 30-day or 1-year survival between patients treated with PCI and those treated with CABG (Table 8). There was no significant interaction between the revascularization modality (PCI versus CABG) and the presence of left main coronary disease. Results were similar when other measures of disease severity (3-vessel disease, left main and/or 3-vessel disease, or coronary jeopardy score) were substituted for left main disease in these models (data not shown). In the adjusted 30-day mortality model, the area under the curve was 0.675, and the likelihood ratio probability value for the whole model was 0.096. In the adjusted 1-year mortality model, the area under the curve was 0.645, and the likelihood ratio probability value for the whole model was 0.242.
Discussion
The findings of this study suggest that PCI and CABG are complementary treatment options for emergency revascularization in patients with cardiogenic shock. Although patients treated with CABG had more extensive and more severe coronary disease than patients treated with PCI, they had similar survival rates at 30 days and 1 year, perhaps because CABG achieved complete revascularization in a greater proportion of patients than PCI did. It is interesting that there was a trend for 96-hour survival to be higher with CABG. This may have been related to the level of care provided in a surgical intensive care unit.
Despite the protocol recommendations with regard to selection of revascularization procedures, this analysis was not limited by those recommendations because many patients with 3-vessel disease had PCI. However, the analysis was probably confounded because patients with 3-vessel disease who were treated with PCI had less severe coronary disease than those who were treated with CABG. In an emergency situation such as cardiogenic shock, investigators may have opted for emergency PCI on stenoses not ideally suited to PCI, knowing that although CABG might achieve more complete revascularization, PCI could be performed more promptly. PCI may also have been performed on patients with poor distal vessels. In addition, the further delay in reperfusion by CABG may suggest that more stable patients were referred for CABG and that very unstable patients were referred for PCI. However, this concept is not supported by the hemodynamic data, which were similar in PCI and CABG patients at baseline.
Diabetes was more prevalent in patients treated with CABG than in those treated with PCI. The investigators’ preference for CABG in diabetic patients may have been influenced by the findings of the Bypass Angioplasty Revascularization Investigation (BARI),15 in which diabetic patients with multivessel disease fared better after CABG than after PCI. However, BARI predated the widespread use of stenting and glycoprotein IIb/IIIa inhibitors, and a 7-year follow-up of the BARI registry, in which the revascularization modality was selected by the attending clinician, showed that diabetic patients had similar survival rates regardless of whether they were treated with PCI or CABG.16 In the present study, the outcome of diabetic patients was not predicted by the revascularization modality. Restenosis has been shown to be a powerful predictor of long-term mortality in diabetics,17 and new stenting technologies such as drug-eluting stents are likely to improve the outcome of diabetic patients by reducing restenosis.18
In the current European Society of Cardiology/American College of Cardiology guidelines,19 AMI with cardiogenic shock is listed as a class IA indication (ie, a condition for which there is evidence for and/or general agreement that a given procedure/treatment is useful and effective) for PCI and a class IA indication for CABG if the patient has suitable coronary anatomy. However, emergency CABG is not widely considered an integral part of contemporary management of patients with cardiogenic shock. In the SHOCK trial,4 which provided the evidence base for the guideline recommendations, 36.7% of patients with left ventricular failure who were assigned to emergency revascularization had CABG as their initial revascularization procedure. Recent data from the National Registry of Myocardial Infarction indicate that CABG is underused in patients with cardiogenic shock, with only 4.9% having early CABG in 2001.20 This underuse may reflect the logistical difficulties of arranging emergency CABG for patients with cardiogenic shock, especially at night or during weekends.
Findings from the SHOCK trial registry showed that revascularization was associated with lower in-hospital mortality in patients with cardiogenic shock.21 In this registry of 884 patients with predominant left ventricular pump failure, 276 (31.2%) had PCI and 109 (12.3%) had CABG. The in-hospital mortality rates were 78.0% in patients treated medically, 46.4% in those treated with PCI, and 23.9% in those treated with CABG (P<0.001). Patients with single-vessel disease had similar in-hospital mortality rates regardless of whether they were treated with PCI or CABG (32.9% versus 33.3%). Patients with 2-vessel disease had higher in-hospital mortality with PCI than with CABG (42.2% versus 17.7%; P=0.025), as did patients with 3-vessel disease (59.35% versus 29.6%; P<0.0001).
Unlike the SHOCK trial, the SHOCK trial registry was nonrandomized, and patients who had diagnostic angiography had more favorable hemodynamic findings than those who did not have angiography, resulting in a selected population.22 No other randomized trials comparing revascularization with medical treatment in patients with cardiogenic shock have included CABG as part of the initial revascularization strategy. The Swiss Multicenter Trial of Angioplasty for Shock (SMASH)23 was terminated early for logistical reasons after 55 patients had been randomized to receive either PCI or medical treatment, and CABG was performed in only 1 patient.
The SHOCK trial protocol recommended PCI only for the infarct-related stenosis, and only 13.6% of patients had emergency PCI on >1 vessel. Given concerns about the possibility of continuing ischemia in other territories and the higher procedural success rates now achieved with more frequent use of stenting and glycoprotein IIb/IIIa inhibitors, it may be appropriate to also treat additional stenoses during the index procedure.24 However, PCI of non–infarct-related stenoses may cause deterioration in coronary flow as a result of embolization of plaque or compromise of side branches in both the infarct and noninfarct zones, thereby impairing collateral blood supply to the infarct zone. In the SHOCK trial, multivessel PCI was associated with a worse outcome than single-vessel PCI.12 This finding may have been confounded by a treatment selection bias in that some patients had PCI rather than CABG because they were considered poor surgical candidates for various reasons.
The procedural success rate of 77.2% in patients who had emergency PCI12 is similar to rates observed in other studies of patients with cardiogenic shock.8,11 Although there have been many advances in PCI (including stenting,12 which reduces reintervention rates, and adjunctive use of glycoprotein IIb/IIIa inhibitors),25–28 patients with cardiogenic shock still have a lower likelihood of successful PCI than patients without shock.4,8–11 For example, a recent German registry study of 1333 patients with cardiogenic shock reported that PCI achieved TIMI 3 flow in only 75.2% of patients.29 In another study of 369 patients with ST-elevation AMI (including 23 patients with cardiogenic shock), drug-eluting stents were compared with bare metal stents and resulted in similar postprocedural vessel patency rates and 30-day complication rates. Patients receiving drug-eluting stents had no increase in stent thrombosis and were less likely to require reintervention within 300 days of follow-up.30
In the SHOCK trial, only 37% of patients received stents, and only 69% received abciximab. A prospective registry study of patients having PCI for cardiogenic shock at the Cleveland Clinic27 showed that stenting increased the likelihood of TIMI grade 3 flow and that adjunctive use of abciximab with stenting increased the survival rate at 1 year.27 In the Abciximab Before Direct Angioplasty and Stenting in Myocardial Infarction Regarding Acute and Long-Term Follow-Up (ADMIRAL) study,31 25 patients presented with cardiogenic shock. Those given adjunctive abciximab before stenting tended to have a lower 6-month event rate (death, AMI, or urgent target-vessel revascularization) than those given a placebo (9.1% versus 28.6%; P=0.23). In the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial of eptifibatide in patients with non–ST-segment elevation acute coronary syndromes, 237 patients developed cardiogenic shock after enrollment. Those given eptifibatide had a lower 30-day mortality rate than those given a placebo (adjusted odds ratio, 0.51; 95% CI, 0.28 to 0.94).28
In the SHOCK trial, 84.8% of patients treated with CABG received >1 graft. Left internal mammary arterial grafts were used in 15.2% of patients. In 87.2% of patients, the surgeons judged that complete revascularization had been achieved. Greater use of arterial grafts and advances in cardioplegia and anesthesia might produce even better results than those observed in this trial.
This analysis had a number of limitations, including the nonrandomized nature of the study and the small number of patients in each treatment group. The treatment strategies used and the time to treatment (particularly in the CABG group) may not be representative of contemporary practice. In addition, multivessel PCI was performed infrequently, and the degree of revascularization achieved was less than that currently recommended.24,32 It is not yet known whether a strategy of acute stenting of the culprit vessel in AMI with subsequent elective treatment of nonculprit stenoses is preferable to complete revascularization in the acute phase. The next logical step would be to perform a randomized comparison of emergency CABG and emergency PCI in patients with cardiogenic shock, including liberal use of drug-eluting stents and glycoprotein IIb/IIIa inhibitors.
Conclusions
Among patients randomized to emergency revascularization in the SHOCK trial, those selected for CABG were more likely to have diabetes and to have more severe coronary disease than those selected for PCI. Despite this disparity in risk factors between the 2 groups, the survival rates at 30 days and 1 year were similar. In cases in which PCI is unlikely to achieve complete revascularization or there are associated mechanical complications or left main or severe 3-vessel coronary disease, CABG should be performed. Emergency CABG is an important component of an early invasive strategy in patients with cardiogenic shock.
Acknowledgments
This work was supported by grants R01-HL-0020-018Z and HL-49970 from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md. Professor White received partial salary funding from the Green Lane Research and Educational Fund Board (Auckland, New Zealand). We gratefully acknowledge the patients and investigators who participated in the SHOCK trial. We also thank Charlene Nell and Barbara Semb for secretarial assistance and Anna Breckon, ELS, for editorial assistance.
Footnotes
Guest Editor for this article was Robert O. Bonow, MD.
References
Hands ME, Rutherford JD, Muller JE, Davies G, Stone PH, Parker C, Braunwald E. The in-hospital development of cardiogenic shock after myocardial infarction: incidence, predictors of occurrence, outcome and prognostic factors. J Am Coll Cardiol. 1989; 14: 40–46.
Holmes DR Jr, Bates ER, Kleiman NS, Sadowski Z, Horgan JH, Morris DC, Califf RM, Berger PB, Topol EJ. Contemporary reperfusion therapy for cardiogenic shock: the GUSTO-I trial experience: the GUSTO-I Investigators: Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries. J Am Coll Cardiol. 1995; 26: 668–674.
Goldberg RJ, Samad NA, Yarzebski J, Gurwitz J, Bigelow C, Gore JM. Temporal trends in cardiogenic shock complicating acute myocardial infarction. N Engl J Med. 1999; 340: 1162–1168.
Hochman JS, Sleeper LA, Webb JG, Sanborn TA, White HD, Talley JD, Buller CE, Jacobs AK, Slater JN, Col J, McKinlay SM, LeJemtel TH, Picard MH, Menegus MA, Boland J, Dzavik V, Thompson CR, Wong SC, Steingart R, Forman R, Aylward PE, Godfrey E, Desvigne-Nickens P, for the SHOCK Investigators. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. N Engl J Med. 1999; 341: 625–634.
Hochman JS, Sleeper LA, White HD, Dzavik V, Wong SC, Menon V, Webb JG, Steingart R, Picard MH, Menegus MA, Boland J, Sanborn T, Buller CE, Modur S, Forman R, Desvigne-Nickens P, Jacobs AK, Slater JN, LeJemtel TH. One-year survival following early revascularization for cardiogenic shock. JAMA. 2001; 285: 190–192.
Sleeper LA, Ramanathan K, Picard MH, LeJerntel TH, White HD, Dzavik V, Tormey D, Avis NE, Hochman JS. Functional status and quality of life after emergency revascularization for cardiogenic shock complicating acute myocardial infarction. J Am Coll Cardiol. 2005; 46: 266–273.
White HD. Angioplasty versus bypass surgery. Lancet. 1995; 346: 1174–1175.Commentary.
Antoniucci D, Valenti R, Santoro GM, Bolognese L, Trapani M, Moschi G, Fazzini PF. Systematic direct angioplasty and stent-supported direct angioplasty therapy for cardiogenic shock complicating acute myocardial infarction: in-hospital and long-term survival. J Am Coll Cardiol. 1998; 31: 294–300.
Moosvi AR, Khaja F, Villanueva L, Gheorghiade M, Douthat L, Goldstein S. Early revascularization improves survival in cardiogenic shock complicating acute myocardial infarction. J Am Coll Cardiol. 1992; 19: 907–914.
Hibbard MD, Holmes DR Jr, Bailey KR, Reeder GS, Bresnahan JF, Gersh BJ. Percutaneous transluminal coronary angioplasty in patients with cardiogenic shock. J Am Coll Cardiol. 1992; 19: 639–646.
Gacioch GM, Ellis SG, Lee L, Bates ER, Kirsh M, Walton JA, Topol EJ. Cardiogenic shock complicating acute myocardial infarction: the use of coronary angioplasty and the integration of the new support devices into patient management. J Am Coll Cardiol. 1992; 19: 647–653.
Webb JG, Lowe AM, Sanborn TA, White HD, Sleeper LA, Carere RG, Buller CE, Wong SC, Boland J, Dzavik V, Porway M, Pate G, Bergman G, Hochman JS, for the SHOCK Investigators. Percutaneous coronary intervention for cardiogenic shock in the SHOCK trial. J Am Coll Cardiol. 2003; 42: 1380–1386.
TIMI Study Group. Comparison of invasive and conservative strategies after treatment with intravenous tissue plasminogen activator in acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) Phase II trial. N Engl J Med. 1989; 320: 618–627.
Califf RM, Phillips HRI, Hindman MC, Mark DB, Lee KL, Behar VS, Johnson RA, Pryor DB, Rosati RA, Wagner GS. Prognostic value of a coronary artery jeopardy score. J Am Coll Cardiol. 1985; 5: 1055–1063.
Bypass Angioplasty Revascularization Investigation (BARI) Investigators. Comparison of coronary bypass surgery with angioplasty in patients with multivessel disease. N Engl J Med. 1996; 335: 217–225.
Feit F, Brooks MM, Sopko G, Keller NM, Rosen A, Krone R, Berger PB, Shemin R, Attubato MJ, Williams DO, Frye R, Detre KM. Long-term clinical outcome in the Bypass Angioplasty Revascularization Investigation Registry: comparison with the randomized trial: BARI Investigators. Circulation. 2000; 101: 2795–2802.
Van Belle E, Ketelers R, Bauters C, Perie M, Abolmaali K, Richard F, LaBlanche JM, McFadden EP, Bertrand ME. Patency of percutaneous transluminal coronary angioplasty sites at 6-month angiographic follow-up: a key determinant of survival in diabetics after coronary balloon angioplasty. Circulation. 2001; 103: 1218–1224.
Morice MC, Serruys PW, Sousa JE, Fajadet J, Ban Hayashi E, Perin M, Colombo A, Schuler G, Barragan P, Guagliumi G, Molnar F, Falotico R. A randomized comparison of a sirolimus-eluting stent with a standard stent for coronary revascularization. N Engl J Med. 2002; 346: 1773–1780.
Antman EM, Anbe DT, Armstrong PW, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr, Alpert JS, Anderson JL, Faxon DP, Fuster V, Gibbons RJ, Gregoratos G, Halperin JL, Hiratzka LF, Hunt SA, Jacobs AK. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1999 Guidelines for the Management of Patients With Acute Myocardial Infarction). Circulation. 2004; 110: 588–636.
Babaev A, Every N, Frederick P, Sichrovsky T, Hochman JS. Trends in revascularization and mortality in patients with cardiogenic shock complicating acute myocardial infarction: observations from the National Registry of Myocardial Infarction. Circulation. 2002; 106 (suppl II): II-364.Abstract.
Webb JG, Sanborn TA, Sleeper LA, Carere RG, Buller CE, Slater JN, Baran KW, Koller PT, Talley JD, Porway M, Hochman JS. Percutaneous coronary intervention for cardiogenic shock in the SHOCK trial registry. Am Heart J. 2001; 141: 964–970.
Wong SC, Sleeper LA, Monrad ES, Menegus MA, Palazzo A, Dzavik V, Jacobs A, Jiang X, Hochman JS. Absence of gender differences in clinical outcomes in patients with cardiogenic shock complicating acute myocardial infarction: a report from the SHOCK trial registry. J Am Coll Cardiol. 2001; 38: 1395–1401.
Urban P, Stauffer JC, Bleed D, Khatchatrian N, Amann W, Bertel O, van den Brand M, Danchin N, Kauffmann U, Meier B, Machecourt J, Pfisterer M, for the (S)MASH Investigators. A randomized evaluation of early revascularization to treat shock complicating acute myocardial infarction: the (Swiss) Multicenter Trial of Angioplasty for Shock—(S)MASH. Eur Heart J. 1999; 20: 1030–1038.
Montalescot G, Andersen HR, Antoniucci D, Betriu A, de Boer MJ, Grip L, Neumann FJ, Rothman MT. Recommendations on percutaneous coronary intervention for the reperfusion of acute ST elevation myocardial infarction. Heart. 2004; 90: e37.
Stone GW, Grines CL, Cox DA, Garcia E, Tcheng JE, Griffin JJ, Guagliumi G, Stuckey T, Turco M, Carroll JD, Rutherford BD, Lansky AJ, for the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) Investigators. Comparison of angioplasty with stenting, with or without abciximab, in acute myocardial infarction. N Engl J Med. 2002; 346: 957–966.
Giri S, Mitchel J, Azar RR, Kiernan FJ, Fram DB, McKay RG, Mennett R, Clive J, Hirst JA. Results of primary percutaneous transluminal coronary angioplasty plus abciximab with or without stenting for acute myocardial infarction complicated by cardiogenic shock. Am J Cardiol. 2002; 89: 126–131.
Chan AW, Chew DP, Bhatt DL, Moliterno DJ, Topol EJ, Ellis SG. Long-term mortality benefit with the combination of stents and abciximab for cardiogenic shock complicating acute myocardial infarction. Am J Cardiol. 2002; 89: 132–136.
Hasdai D, Harrington RA, Hochman JS, Califf RM, Battler A, Box JW, Simoons ML, Deckers J, Topol EJ, Holmes DR Jr. Platelet glycoprotein IIb/IIIa blockade and outcome of cardiogenic shock complicating acute coronary syndromes without persistent ST-segment elevation. J Am Coll Cardiol. 2000; 36: 685–692.
Zeymer U, Vogt A, Zahn R, Weber MA, Tebbe U, Gottwik M, Bonzel T, Senges J, Neuhaus KL, for the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausrtze (ALKK). Predictors of in-hospital mortality in 1333 patients with acute myocardial infarction complicated by cardiogenic shock treated with primary percutaneous coronary intervention (PCI): results of the primary PCI registry of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausrtze (ALKK). Eur Heart J. 2004; 25: 322–328.
Lemos PA, Saia F, Hofma SH, Daemen J, Ong AT, Arampatzis CA, Hoye A, McFadden E, Sianos G, Smits PC, van der Giessen WJ, de Feyter P, van Domburg RT, Serruys PW. Short- and long-term clinical benefit of sirolimus-eluting stents compared to conventional bare stents for patients with acute myocardial infarction. J Am Coll Cardiol. 2004; 43: 704–708.
Montalescot G, Barragan P, Wittenberg O, Elhadad S, Lefevre T, Loubeyre C, Lafont A, Zupan M, Paganelli F, Pinton P. Primary stenting with abciximab in acute myocardial infarction complicated by cardiogenic shock (the ADMIRAL trial). J Am Coll Cardiol. 2002; 39 (suppl A): 43A.Abstract.
Silber S, Albertsson P, Aviles FF, Camici PG, Colombo A, Hamm C, Jorgensen E, Marco J, Nordrehaug JE, Ruzyllo W, Urban P, Stone GW, Wijns W. Guidelines for percutaneous coronary interventions: the Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology. Eur Heart J. 2005; 26: 804–847.(Harvey D. White, DSc, FCS)