Valsalva prosthesis in aortic valve-sparing operations
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《血管的通路杂志》
a Department of Cardiac Surgery, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
b Department of Cardiology, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
c Cardiac Surgery Intensive Care Unit, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
Presented at the joint 19th Annual Meeting of the European Association for Cardio-thoracic Surgery and the 13th Annual Meeting of the European Society of Thoracic Surgeons, Barcelona, Spain, September 25–28, 2005.
Abstract
Aortic valve-sparing operations have provided very good clinical outcomes. However, the absence of the sinuses of Valsalva might limit valve durability. The Gelweave ValsalvaTM prosthesis, which presents pre-fashioned neo-sinuses, has been designed in order to avoid early leaflets deterioration. We report our results in 63 patients who underwent valve-sparing operations (reimplantation technique) using the Gelweave ValsalvaTM graft. The main indication was ascending aorta aneurysm or annuloaortic ectasia, with or without aortic insufficiency. The operation was performed also in cases of Marfan syndrome, Bicuspid Aortic Valve (BAV), and acute Type A dissection. In-hospital mortality was of 4.7%, and two thirds were acute Type A dissection patients (P=0.01). There were no late deaths. Three years freedom from grade 3–4 AI and freedom from late aortic valve replacement were 91.7±4.3% and 93.8±5.1%, respectively. Aortic valve-sparing operations show good results in patients electively operated for aortic root ectasia. Aortic cusps repair may lead to late failure. Even if the Gelweave ValsalvaTM prosthesis is easy to implant and it also reproduces pseudosinuses, a long-term follow up is necessary to determine if this graft may reduce leaflets deterioration.
Key Words: Aortic valve insufficiency; Ascending aorta aneurysm; Aortic valve repair
1. Introduction
The use of aortic valve-sparing operations has increased in the last years due to a better understanding of the aortic root anatomy and physiology. The two main surgical procedures adopted are the remodelling and the reimplantation techniques. The remodelling technique allows the reconstruction of the sinuses, but it does not stabilize the annulus, while the classical reimplantation prevents annular dilatation but completely abolishes the sinuses.
Actually, the cylindrical shape of the tube has been demonstrated to be a cause of increased stress motion of the leaflets and leading to sudden cusps deterioration [1,2]. The sinuses of Valsalva are of paramount importance in ensuring normal function of the aortic valve and they modulate the coronary flow pattern [3]. Then, many surgical changes in the original procedure have been suggested in order to recreate the sinuses [4,5]. In 2000, De Paulis [6] introduced a modified Dacron tube (Gelwave Valsalva Terumo-Vascutek, Renfrewshire, Scotland, UK) which mimics the Valsalva sinuses. In the current paper we describe our technique using this conduit and we analyze the clinical results in 63 patients.
2. Materials and methods
2.1. Patient population
From March 2002 to March 2005, 265 patients underwent aortic root surgery and in 63 of them (23.8%), the aortic valve reimplantation with the Valsalva conduit was performed. All procedures were performed by the same surgeon (RDB).
Demographic and clinical data are reported in Table 1. Preoperative evaluation included transthoracic and/or transesophageal echocardiography (TEE), CT scan and coro- narography. Preoperative echocardiographic data are shown in Table 2. Intraoperative TEE was always performed.
2.2. Surgical technique
Cardiopulmonary bypass (CPB) was instituted in the conventional way, at 32 °C of systemic temperature. In cases of aortic arch aneurysms or acute type A dissection, a peripheral cannulation, as the right femoral or axillary arteries, was preferred. In these cases, a moderate hypothermia (nasopharyngeal temperature of 26 °C) and Antegrade Selective Cerebral Perfusion (ASCP) were used. Our technique of brain protection has been described in detail elsewhere [7].
Myocardial protection was achieved by antegrade infusion of cold (5–10 °C) crystalloid HTK solution (Custodiol).
The surgical procedure followed the steps described by David and Feindel in their original article [8]. Once the aortic wall has been excised, U stitches of Ethibon 3/0 are passed below the aortic valve, at the ventriculo-arterial junction, in a circular fashion. The aortic annulus is measured with a standard valve sizer, and then the prosthetic tube is chosen by an oversize of 5 mm. In the case of dilated annulus, the ST junction is sized instead: once a proper leaflet coaptation is obtained by pulling on the three commissures, the sino-tubular (ST) junction can be easily measured and the 5-mm oversize Valsalva graft is chosen. Besides, a subcommissural annuloplasty is performed using plegeted Ethibond 2/0 at the level of the interleaflet triangle, as described by El Khoury et al. [9].
The key point of the surgical technique is the correct placement of the commissures at the level of the conjunction between the skirted section and the standard graft, which represents the new ST junction. The height of the commissures from the annulus to the top of the commissure are sized and the sub-annular U stitches are then passed through the tubular prosthesis, at the level which allows the top of the commissures to reach the new STJ (usually at the base of the skirt or a little higher). In the uncommon instance when the commissures are taller than the skirt of the graft, part of the collar can be used to adapt the graft to the patient anatomy. The height of the three commissures is usually different, and the one between the right and the left cusp is shorter. Therefore, the base of the skirt can be scalloped to make up for this different length.
Once these stitches have been tied, the commissures are retrieved from inside and pulled at the level of the neo-ST junction. Next, the valve remnants are secured to the Dacron wall and the coronary buttons reimplanted.
In 13 (20.6%) cases, a leaflet repair was necessary and consisted of: shortening of the free margin either by central plication or by weaving a double layer of 6/0 polytetrafluoroethylene suture along the free edge in 8 patients; raphe resection with annular plication in 7 patients (in 2 of these, shortening of the free margin by a double layer suture was also performed and, in another one, an autologous pericardium patch was utilized to reconstruct the leaflet where the raphe was present); and cusp fenestration closure with 6/0 polypropylene in 3 patients. Aortic arch surgery was associated in 11 patients (17.5%), and in two of such cases the Elephant trunk technique was utilized. ASCP was used in all those cases. Other operative data are summarized in Table 3.
The result of the procedure was checked with TEE after weaning from CPB.
Antiplatelet therapy was started from the second postoperative day and prescribed as long-term therapy thereafter.
2.3. Follow-up
Before hospital discharge, valve function was re-evaluated using transthoracic echocardiography. Mean time follow-up ranged from 6 to 36 months (16.6±9.1).
After discharge, echocardiography was performed at 3 and 9 months following the operation and then once per year. The degree of residual AI was assessed semiquantitatively as follows: 0 none, 1 minimal, 2 mild, 3 moderate, 4 severe. In the case of grade 3 AI or greater, echocardiography was repeated at shorter intervals.
2.4. Statistical analysis
Statistical analysis was performed with SPSS 11.0 statistical software (SPSS, Chicago, IL). Continuous variables were expressed as the mean±S.D. and were compared with an unpaired two-tailed t-test. Categorical variables were analyzed with a 2 or Fisher's exact tests. Survival analyses were calculated using the Kaplan–Meier actuarial technique; in addition, freedom from grade 3 or 4 aortic regurgitation and freedom from aortic valve replacement (AVR) were calculated.
3. Results
3.1. Early outcome
There were three in-hospital deaths (4.7%). The first patient, operated on because of acute Type A dissection, was in critical circumstances with signs of peripheral ischemia and tamponade. Surgery was uneventful but the patient died after 10 days because of MOF. Another patient, affected by acute aortic dissection, developed a severe AI on the 2nd postoperative day. At reoperation the left and the non-coronary cusps prolapsed because of commissural tearing. The patient underwent aortic valve replacement (AVR) with a mechanical device. Three days later a TEE exam showed the prosthesis malfunctioning due to a mechanical leaflet blockage. This was caused by a portion of native tissue which went down inside the prosthesis. The patient underwent a Bentall procedure (3rd operation). Weaning from cardiopulmonary bypass was unfeasible. A biventricular assist device was implanted but the patient died 2 days later. The last non-surviving patient was operated on for annuloaortic ectasia complicated by aortic distal thoracic aorta dissection. The patient developed renal insufficiency and died because of MOF on the 12th postoperative day.
At the discharge echocardiography, grade 3 of AI was found in three patients.
3.2. Follow-up results
There were no deaths in the follow-up time. The 3-year survival for patients with aortic root aneurysm was 94.7±2.9% (Fig. 1).
Echocardiography showed a good reconstruction of the sinuses of Valsalva in all patients (Fig. 2A). The CT scan and the angiography (Fig. 2B) confirmed the good anatomical reconstruction.
Four patients had 3 to 4+ AI: 3 patients required late AVR (all had an associated cusp repair procedure) and the other one is still asymptomatic with normal left ventricular size and function and is being followed closely with serial echocardiograms.
The incidence of grade 3 to 4 AI was significantly higher in patients who had undergone cusp valve repair (23.1 vs. 2%; P=0.005), and AI was already present very soon in the immediate postoperative period.
The three-years freedom from grade 3–4 AI and the 3-years freedom from late AVR was 91.7±4.3% and 93.8±5.1%, respectively (Fig. 3A, B). Grade of AI early postop and at last visit are plotted in Fig. 4. During follow-up, neither bleeding complications nor thrombobolic events, nor endocarditis occurred.
4. Conclusions
The last three decades have witnessed major progress in the management of aortic root aneurysms. The introduction of the composite graft procedure, as described in 1968 by Bentall, has been one of the most significant developments in this field [10], achieving a significant prolongation of life expectancy for patients affected by a variety of conditions involving the ascending aorta and the aortic root [11].
However, despite refinements in the design of cardiac prostheses and anticoagulation management, mechanical valves are still associated with a variety of complications, often leading to serious disability or death [12].
In order to avoid the drawbacks of valve prosthesis, aortic valve sparing operations have recently gained popularity. Based on a clear understanding of aortic root structure and function [13,14] new surgical techniques have been introduced to preserve the aortic valve [8–15]. Although attention is given to create neosinuses [4,5], the operation is carried out using a non-compliant tube (Dacron) which may result in leaflet damage [1,2].
This study reports our experience in the aortic valve reimplantation procedure using the Valsalva conduit. This graft has pre-fashioned neosinuses and no additional modification of the implantation technique is required [6]. The key point is the correct placement of the commissures at the level of the distal ridge of the prosthesis (the neo-STJ), avoiding their lateral displacement and consequent AI. The presence of neosinuses also makes coronary ostial reimplantation easier and tension-free.
Regarding our results, no complications have been associated with the prosthesis and in all cases sinuses of proper shape and dimension were obtained (Fig. 2). We report a negative experience in patients with acute aortic dissection: 2 deaths out of 4 patients with Type A dissection. We believe that reimplanting 3–4 mm of a pathological aortic wall inside the prosthesis, even if it is not involved in the dissection, may predispose to a secondary rupture, with consequent AI. After these disappointing results, we abandoned this technique in acute aortic dissection.
At the beginning of our experience, the procedure was applied only when leaflets were unspoiled. Later, we started to perform the reimplantation procedure also in patients with BAV, or slightly damaged leaflets. The repair of the leaflets has been performed in 13 cases, and 5 of them were BAV. Nonetheless, our results indicate that associated procedures on valve leaflet significantly increase the probability of residual AI.
The optimal timing of the procedure is still controversial. When the aortic root dilates, aortic leaflets' stress increases and the leaflets start to deteriorate, this being the major cause of an unsuccessful valve-sparing procedure. We operate on the aortic root when the diameter reaches 50 mm (even less if severe aortic regurgitation is present) or 45 mm in cases of chronic aortic dissection, family history of aortic dissection or aneurysm, and in a context of aortic wall disease, such as Marfan or other connective tissue disorders and in the bicuspid aortic valve cases. In the present population, the average preoperative diameter of the ascending aorta was 49 mm. In some patients the indication for surgery was the size of the aortic root and ascending aorta. In other cases, the major indication was the presence of AI.
The present study has many limitations. The examined period was only 16.6 months of mean and a longer follow-up is required, to determine the success of this procedure, and to compare it with other more consolidated techniques such as the Bentall procedure. Another drawback is the lack of a more sophisticated postoperative assessment, as measurement of coronary flow rates, aortic leaflets opening and closure velocities, distance of leaflets edges to the graft etc.
The reimplantation technique with the Gelweave ValsalvaTM graft is currently our procedure of choice for patients operated on for aortic root aneurysms with the absence or mild deterioration of aortic leaflets, even in cases of BAV. The results obtained are gratifying but, limited by the time frame and the incidence of residual AI, urges caution appropriate. The anatomy of the aortic root is extremely complex and difficult to reproduce but the use of this graft may provide an almost normal anatomy.
Indeed, since life-long anticoagulation is not needed, the use of this conduit for the aortic valve reimplantation may represent a clear benefit for the patients, if the long-term will demonstrate such good results as that of the Bentall procedure.
Appendix. Conference discussion
Dr T. Aybek (Frankfurt, Germany): I see two theoretical problems using this prosthesis. One of them is in native aortic valve, the commissural line is straight, and in this prosthesis there is a concavity.
And second, we know in aortic root aneurysms, the length of the commissural line is a little bit longer, maybe longer than this concavity of this prosthesis. Do you have any problems using this prosthesis in practice
Dr Pacini: I'll answer your last question first.
The key point using this prosthesis is the correct placement of the commissure at the level of the sinotubular junction of the prosthesis. So you have to measure the height of the root from the annular suture line, up to the top of the commissure. Usually, you have to take out the whole collar of the prosthesis and then match the measured length of the root with the height of the skirt. In this way you are sure that your commissures will be at the right level.
And for the first question, it is not really true that there is a concavity, because as shown by echocardiography, the short axis view of our patients, has a normal tri-foliate aspect. And this is because when you suture the annulus up to the top of the sinotubular junction, you create a fixed and straight line, a column, so it is not really true that the commissures are bulging.
Dr Aybek: Another question. You show that there are 4 patients with aortic regurgitation, in III and IV. How many patients do you have with aortic regurgitation in I and II in follow-up
Dr Pacini: As you can see in this slide, we discharged 3 patients with Grade III aortic insufficiency, and all of these 3 patients developed a severe aortic insufficiency during follow-up and all of them were reoperated. And only 1 patient, at the last visit, had Grade III aortic insufficiency and no Grade IV.
Dr R. Dion (Leiden, The Netherlands): In some of the patients you keep a part of the skirt plus the commissure height to match the height of the commissure of the prosthesis to that of the patient
Dr Pacini: Yes.
Dr Dion: And you have no anatomic discrepancy between the skirt, which is perfectly cylindric, and the Valsalva sinus which is not
Dr Pacini: No, because the commissures are straightened out. With the suture line the commissures become straight and only the sinuses bulge out.
References
Leyh RG, Schmidtke C, Sievers HH, Yacoub MH. Opening and closing characteristics of the aortic valve after different types of valve-preserving surgery. Circulation 1999; 100:2153–2160.
Grande-Allen KJ, Cochran RP, Reinhall PG, Kunzelmann KS. Re-creation of sinuses is important for sparing the aortic valve: a finite element study. J Thorac Cardiovasc Surg 2000; 119:753–763.
Bellhouse BJ, Bellhouse F, Abbot JA, Talbot L. Mechanism of valvular incompetence in aortic sinus dilatation. Cardiovasc Res 1973; 7:490–494.
David TE, Armstrong S, Ivanov J, Feindel CM, Omran A, Webb G. Results of aortic valve-sparing operations. J Thorac Cardiovasc Surg 2001; 122:39–46.
Demers P, Craig Miller D. Simple modification of ‘T. David-V’ valve-sparing aortic root replacement to create graft pseudosinuses. Ann Thorac Surg 2004; 78:1479–1481.
De Paulis R, De Matteis GM, Nardi P, Scaffa R, Colella D, Chiariello L. A new aortic Dacron conduit for surgical treatment of aortic root pathology. Ital Heart J 2000; 1:457–463.
Di Bartolomeo R, Pacini D, Di Eusanio M, Pierangeli A. Antegrade selective cerebral perfusion during operations on the thoracic aorta: our experience. Ann Thorac Surg 2000; 70:10–6.
David TE, Feindel M. An aortic valve sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovas Surg 1992; 103:617–622.
El Khoury G, Vanoverschelde JL, Glineur D, Poncelet A, Verhelst R, Astarci P, Underwood MJ, Noirhomme P. Repair of aortic valve prolapse: experience with 44 patients. Eur J Cardiothorac Surg 2004; 26:628–633.
Bentall HH, De Bono A. A technique for complete replacement of the ascending aorta. Thorax 1968; 23:338–339.
Gott VL, Cameron DE, Alejo DE, Greene PS, Shake JG, Caparrelli DJ, Dietz HC. Aortic root replacement in 271 Marfan patients: a 24-year experience. Ann Thorac Surg 2002; 73:438–443.
Pacini D, Ranocchi F, Angeli E, Settepani F, Pagliaro M, Martin-Suarez S, Di Bartolomeo R, Pierangeli A. Aortic root replacement with composite valve graft. Ann Thorac Surg 2003; 76:90–98.
David TE. An anatomic and physiologic approach to acquired heart disease. Eur J Cardiothorac Surg 1995; 9:175–180.
83:Underwood MJ, El Khoury G, Deronck D, Glineur D, Dion R. The aortic root: structure, function, and surgical reconstruction. Heart 2000;376–380.
Yacoub MH, Fagan A, Stassano P, Radley-Smith R. Results of valve conserving operations for aortic regurgitation. Circulation 1983; 68:311–321.(Roberto Di Bartolomeo, Da)
b Department of Cardiology, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
c Cardiac Surgery Intensive Care Unit, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
Presented at the joint 19th Annual Meeting of the European Association for Cardio-thoracic Surgery and the 13th Annual Meeting of the European Society of Thoracic Surgeons, Barcelona, Spain, September 25–28, 2005.
Abstract
Aortic valve-sparing operations have provided very good clinical outcomes. However, the absence of the sinuses of Valsalva might limit valve durability. The Gelweave ValsalvaTM prosthesis, which presents pre-fashioned neo-sinuses, has been designed in order to avoid early leaflets deterioration. We report our results in 63 patients who underwent valve-sparing operations (reimplantation technique) using the Gelweave ValsalvaTM graft. The main indication was ascending aorta aneurysm or annuloaortic ectasia, with or without aortic insufficiency. The operation was performed also in cases of Marfan syndrome, Bicuspid Aortic Valve (BAV), and acute Type A dissection. In-hospital mortality was of 4.7%, and two thirds were acute Type A dissection patients (P=0.01). There were no late deaths. Three years freedom from grade 3–4 AI and freedom from late aortic valve replacement were 91.7±4.3% and 93.8±5.1%, respectively. Aortic valve-sparing operations show good results in patients electively operated for aortic root ectasia. Aortic cusps repair may lead to late failure. Even if the Gelweave ValsalvaTM prosthesis is easy to implant and it also reproduces pseudosinuses, a long-term follow up is necessary to determine if this graft may reduce leaflets deterioration.
Key Words: Aortic valve insufficiency; Ascending aorta aneurysm; Aortic valve repair
1. Introduction
The use of aortic valve-sparing operations has increased in the last years due to a better understanding of the aortic root anatomy and physiology. The two main surgical procedures adopted are the remodelling and the reimplantation techniques. The remodelling technique allows the reconstruction of the sinuses, but it does not stabilize the annulus, while the classical reimplantation prevents annular dilatation but completely abolishes the sinuses.
Actually, the cylindrical shape of the tube has been demonstrated to be a cause of increased stress motion of the leaflets and leading to sudden cusps deterioration [1,2]. The sinuses of Valsalva are of paramount importance in ensuring normal function of the aortic valve and they modulate the coronary flow pattern [3]. Then, many surgical changes in the original procedure have been suggested in order to recreate the sinuses [4,5]. In 2000, De Paulis [6] introduced a modified Dacron tube (Gelwave Valsalva Terumo-Vascutek, Renfrewshire, Scotland, UK) which mimics the Valsalva sinuses. In the current paper we describe our technique using this conduit and we analyze the clinical results in 63 patients.
2. Materials and methods
2.1. Patient population
From March 2002 to March 2005, 265 patients underwent aortic root surgery and in 63 of them (23.8%), the aortic valve reimplantation with the Valsalva conduit was performed. All procedures were performed by the same surgeon (RDB).
Demographic and clinical data are reported in Table 1. Preoperative evaluation included transthoracic and/or transesophageal echocardiography (TEE), CT scan and coro- narography. Preoperative echocardiographic data are shown in Table 2. Intraoperative TEE was always performed.
2.2. Surgical technique
Cardiopulmonary bypass (CPB) was instituted in the conventional way, at 32 °C of systemic temperature. In cases of aortic arch aneurysms or acute type A dissection, a peripheral cannulation, as the right femoral or axillary arteries, was preferred. In these cases, a moderate hypothermia (nasopharyngeal temperature of 26 °C) and Antegrade Selective Cerebral Perfusion (ASCP) were used. Our technique of brain protection has been described in detail elsewhere [7].
Myocardial protection was achieved by antegrade infusion of cold (5–10 °C) crystalloid HTK solution (Custodiol).
The surgical procedure followed the steps described by David and Feindel in their original article [8]. Once the aortic wall has been excised, U stitches of Ethibon 3/0 are passed below the aortic valve, at the ventriculo-arterial junction, in a circular fashion. The aortic annulus is measured with a standard valve sizer, and then the prosthetic tube is chosen by an oversize of 5 mm. In the case of dilated annulus, the ST junction is sized instead: once a proper leaflet coaptation is obtained by pulling on the three commissures, the sino-tubular (ST) junction can be easily measured and the 5-mm oversize Valsalva graft is chosen. Besides, a subcommissural annuloplasty is performed using plegeted Ethibond 2/0 at the level of the interleaflet triangle, as described by El Khoury et al. [9].
The key point of the surgical technique is the correct placement of the commissures at the level of the conjunction between the skirted section and the standard graft, which represents the new ST junction. The height of the commissures from the annulus to the top of the commissure are sized and the sub-annular U stitches are then passed through the tubular prosthesis, at the level which allows the top of the commissures to reach the new STJ (usually at the base of the skirt or a little higher). In the uncommon instance when the commissures are taller than the skirt of the graft, part of the collar can be used to adapt the graft to the patient anatomy. The height of the three commissures is usually different, and the one between the right and the left cusp is shorter. Therefore, the base of the skirt can be scalloped to make up for this different length.
Once these stitches have been tied, the commissures are retrieved from inside and pulled at the level of the neo-ST junction. Next, the valve remnants are secured to the Dacron wall and the coronary buttons reimplanted.
In 13 (20.6%) cases, a leaflet repair was necessary and consisted of: shortening of the free margin either by central plication or by weaving a double layer of 6/0 polytetrafluoroethylene suture along the free edge in 8 patients; raphe resection with annular plication in 7 patients (in 2 of these, shortening of the free margin by a double layer suture was also performed and, in another one, an autologous pericardium patch was utilized to reconstruct the leaflet where the raphe was present); and cusp fenestration closure with 6/0 polypropylene in 3 patients. Aortic arch surgery was associated in 11 patients (17.5%), and in two of such cases the Elephant trunk technique was utilized. ASCP was used in all those cases. Other operative data are summarized in Table 3.
The result of the procedure was checked with TEE after weaning from CPB.
Antiplatelet therapy was started from the second postoperative day and prescribed as long-term therapy thereafter.
2.3. Follow-up
Before hospital discharge, valve function was re-evaluated using transthoracic echocardiography. Mean time follow-up ranged from 6 to 36 months (16.6±9.1).
After discharge, echocardiography was performed at 3 and 9 months following the operation and then once per year. The degree of residual AI was assessed semiquantitatively as follows: 0 none, 1 minimal, 2 mild, 3 moderate, 4 severe. In the case of grade 3 AI or greater, echocardiography was repeated at shorter intervals.
2.4. Statistical analysis
Statistical analysis was performed with SPSS 11.0 statistical software (SPSS, Chicago, IL). Continuous variables were expressed as the mean±S.D. and were compared with an unpaired two-tailed t-test. Categorical variables were analyzed with a 2 or Fisher's exact tests. Survival analyses were calculated using the Kaplan–Meier actuarial technique; in addition, freedom from grade 3 or 4 aortic regurgitation and freedom from aortic valve replacement (AVR) were calculated.
3. Results
3.1. Early outcome
There were three in-hospital deaths (4.7%). The first patient, operated on because of acute Type A dissection, was in critical circumstances with signs of peripheral ischemia and tamponade. Surgery was uneventful but the patient died after 10 days because of MOF. Another patient, affected by acute aortic dissection, developed a severe AI on the 2nd postoperative day. At reoperation the left and the non-coronary cusps prolapsed because of commissural tearing. The patient underwent aortic valve replacement (AVR) with a mechanical device. Three days later a TEE exam showed the prosthesis malfunctioning due to a mechanical leaflet blockage. This was caused by a portion of native tissue which went down inside the prosthesis. The patient underwent a Bentall procedure (3rd operation). Weaning from cardiopulmonary bypass was unfeasible. A biventricular assist device was implanted but the patient died 2 days later. The last non-surviving patient was operated on for annuloaortic ectasia complicated by aortic distal thoracic aorta dissection. The patient developed renal insufficiency and died because of MOF on the 12th postoperative day.
At the discharge echocardiography, grade 3 of AI was found in three patients.
3.2. Follow-up results
There were no deaths in the follow-up time. The 3-year survival for patients with aortic root aneurysm was 94.7±2.9% (Fig. 1).
Echocardiography showed a good reconstruction of the sinuses of Valsalva in all patients (Fig. 2A). The CT scan and the angiography (Fig. 2B) confirmed the good anatomical reconstruction.
Four patients had 3 to 4+ AI: 3 patients required late AVR (all had an associated cusp repair procedure) and the other one is still asymptomatic with normal left ventricular size and function and is being followed closely with serial echocardiograms.
The incidence of grade 3 to 4 AI was significantly higher in patients who had undergone cusp valve repair (23.1 vs. 2%; P=0.005), and AI was already present very soon in the immediate postoperative period.
The three-years freedom from grade 3–4 AI and the 3-years freedom from late AVR was 91.7±4.3% and 93.8±5.1%, respectively (Fig. 3A, B). Grade of AI early postop and at last visit are plotted in Fig. 4. During follow-up, neither bleeding complications nor thrombobolic events, nor endocarditis occurred.
4. Conclusions
The last three decades have witnessed major progress in the management of aortic root aneurysms. The introduction of the composite graft procedure, as described in 1968 by Bentall, has been one of the most significant developments in this field [10], achieving a significant prolongation of life expectancy for patients affected by a variety of conditions involving the ascending aorta and the aortic root [11].
However, despite refinements in the design of cardiac prostheses and anticoagulation management, mechanical valves are still associated with a variety of complications, often leading to serious disability or death [12].
In order to avoid the drawbacks of valve prosthesis, aortic valve sparing operations have recently gained popularity. Based on a clear understanding of aortic root structure and function [13,14] new surgical techniques have been introduced to preserve the aortic valve [8–15]. Although attention is given to create neosinuses [4,5], the operation is carried out using a non-compliant tube (Dacron) which may result in leaflet damage [1,2].
This study reports our experience in the aortic valve reimplantation procedure using the Valsalva conduit. This graft has pre-fashioned neosinuses and no additional modification of the implantation technique is required [6]. The key point is the correct placement of the commissures at the level of the distal ridge of the prosthesis (the neo-STJ), avoiding their lateral displacement and consequent AI. The presence of neosinuses also makes coronary ostial reimplantation easier and tension-free.
Regarding our results, no complications have been associated with the prosthesis and in all cases sinuses of proper shape and dimension were obtained (Fig. 2). We report a negative experience in patients with acute aortic dissection: 2 deaths out of 4 patients with Type A dissection. We believe that reimplanting 3–4 mm of a pathological aortic wall inside the prosthesis, even if it is not involved in the dissection, may predispose to a secondary rupture, with consequent AI. After these disappointing results, we abandoned this technique in acute aortic dissection.
At the beginning of our experience, the procedure was applied only when leaflets were unspoiled. Later, we started to perform the reimplantation procedure also in patients with BAV, or slightly damaged leaflets. The repair of the leaflets has been performed in 13 cases, and 5 of them were BAV. Nonetheless, our results indicate that associated procedures on valve leaflet significantly increase the probability of residual AI.
The optimal timing of the procedure is still controversial. When the aortic root dilates, aortic leaflets' stress increases and the leaflets start to deteriorate, this being the major cause of an unsuccessful valve-sparing procedure. We operate on the aortic root when the diameter reaches 50 mm (even less if severe aortic regurgitation is present) or 45 mm in cases of chronic aortic dissection, family history of aortic dissection or aneurysm, and in a context of aortic wall disease, such as Marfan or other connective tissue disorders and in the bicuspid aortic valve cases. In the present population, the average preoperative diameter of the ascending aorta was 49 mm. In some patients the indication for surgery was the size of the aortic root and ascending aorta. In other cases, the major indication was the presence of AI.
The present study has many limitations. The examined period was only 16.6 months of mean and a longer follow-up is required, to determine the success of this procedure, and to compare it with other more consolidated techniques such as the Bentall procedure. Another drawback is the lack of a more sophisticated postoperative assessment, as measurement of coronary flow rates, aortic leaflets opening and closure velocities, distance of leaflets edges to the graft etc.
The reimplantation technique with the Gelweave ValsalvaTM graft is currently our procedure of choice for patients operated on for aortic root aneurysms with the absence or mild deterioration of aortic leaflets, even in cases of BAV. The results obtained are gratifying but, limited by the time frame and the incidence of residual AI, urges caution appropriate. The anatomy of the aortic root is extremely complex and difficult to reproduce but the use of this graft may provide an almost normal anatomy.
Indeed, since life-long anticoagulation is not needed, the use of this conduit for the aortic valve reimplantation may represent a clear benefit for the patients, if the long-term will demonstrate such good results as that of the Bentall procedure.
Appendix. Conference discussion
Dr T. Aybek (Frankfurt, Germany): I see two theoretical problems using this prosthesis. One of them is in native aortic valve, the commissural line is straight, and in this prosthesis there is a concavity.
And second, we know in aortic root aneurysms, the length of the commissural line is a little bit longer, maybe longer than this concavity of this prosthesis. Do you have any problems using this prosthesis in practice
Dr Pacini: I'll answer your last question first.
The key point using this prosthesis is the correct placement of the commissure at the level of the sinotubular junction of the prosthesis. So you have to measure the height of the root from the annular suture line, up to the top of the commissure. Usually, you have to take out the whole collar of the prosthesis and then match the measured length of the root with the height of the skirt. In this way you are sure that your commissures will be at the right level.
And for the first question, it is not really true that there is a concavity, because as shown by echocardiography, the short axis view of our patients, has a normal tri-foliate aspect. And this is because when you suture the annulus up to the top of the sinotubular junction, you create a fixed and straight line, a column, so it is not really true that the commissures are bulging.
Dr Aybek: Another question. You show that there are 4 patients with aortic regurgitation, in III and IV. How many patients do you have with aortic regurgitation in I and II in follow-up
Dr Pacini: As you can see in this slide, we discharged 3 patients with Grade III aortic insufficiency, and all of these 3 patients developed a severe aortic insufficiency during follow-up and all of them were reoperated. And only 1 patient, at the last visit, had Grade III aortic insufficiency and no Grade IV.
Dr R. Dion (Leiden, The Netherlands): In some of the patients you keep a part of the skirt plus the commissure height to match the height of the commissure of the prosthesis to that of the patient
Dr Pacini: Yes.
Dr Dion: And you have no anatomic discrepancy between the skirt, which is perfectly cylindric, and the Valsalva sinus which is not
Dr Pacini: No, because the commissures are straightened out. With the suture line the commissures become straight and only the sinuses bulge out.
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