Aortic valve-sparing operations in patients with aneurysms of the aortic root or ascending aorta: preliminary results
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《血管的通路杂志》
Department of Cardiac Surgery, Istituto Clinico Humanitas, Via Manzoni 56, cap: 20089, Rozzano (MI), Italy
Presented at the 53rd International Congress of the European Society for the Cardiovascular Surgery, Ljubjana, Slovenia, June 2–5, 2004.
Abstract
Objective: Aortic valve-sparing operations were developed to preserve the native aortic valve in patients with aneurysms of the aortic root or ascending aorta and normal aortic valve leaflets. This paper describes our initial experience with valve-sparing operations and early clinical and echocardiographic results obtained. Methods: From October 2002 to March 2004, 32 consecutive patients underwent aortic valve-sparing operations at the Istituto Clinico Humanitas, Rozzano, Italy. Preoperative transesophageal echocardiography showed moderate or severe aortic incompetence (AI) in 15 patients (47%). Twenty-nine patients underwent reimplantation of the aortic valve and 3 patients remodeling of one sinus. In 2 cases prolapsing cusp repair was carried out. Results: There were no intraoperative deaths. At discharge, two-dimensional echocardiogram showed no or trivial aortic incompetence (AI) in 17 (52%) patients and mild AI in 13 (42%); 2 (6%) patients had severe AI requiring reoperation, respectively 4 and 6 weeks later. Conclusions: The valve-sparing procedures showed good preliminary results, thus encouraging further use of this type of repair. However, further larger studies and long-term results are needed in order to define the durability of these techniques.
Key Words: Aortic valve leaflets; Valve-sparing operations; Aortic root
1. Introduction
Aortic valve-sparing operations were developed to preserve the native aortic valve in patients with aneurysms of the aortic root or ascending aorta and normal aortic valve leaflets [1]; in recent years indications have been extended also to valves having cusps without gross structural defects [2,3]. These kind of aneurysms are frequently associated with aortic incompetence (AI) which is caused by loss of the sino-tubular junction, dilatation or distortion of one or more sinuses of Valsalva, annuloaortic ectasia or a combination of these problems [4]. The conventional treatment consists of composite replacement of the aortic valve and the ascending aorta [5]; though it’s considered ‘safe’, it is not free from complications including thromboembolism, endocarditis, and long-term anticoagulation related problems [6]. Then, from October 2002, we have adopted valve-sparing operations to treat patients with root dilatation and aortic cusps without gross structural defects.
This paper describes our initial experience with valve-sparing operations and early clinical and echocardiographic results obtained.
2. Material and methods
From October 2002 to March 2004, 32 consecutive patients underwent aortic valve-sparing operations at the Istituto Clinico Humanitas, Rozzano, Italy. Our standard indications have been aneurysms of the aortic root and/or ascending aorta and aortic cusps without gross structural defects. The final decision to preserve the valve was made intraoperatively by the surgeon after inspection of valve cusps and root geometry. When the structural defects of the cusps were considered unsuitable for repair the Bentall procedure was performed. Demographic data are listed in Table 1. Patients were predominantly male and mean age was 58 ±13 (range 28–83). The mean ascending aorta diameter was 5.1±1.1 cm. Among the patients with no, trivial or mild AI the mean ascending aorta diameter was 5.0±1.0 cm and of these 33.3% had a bicuspid aortic valve.
2.1. Operative techniques
A median sternotomy was performed and hypothermic cardiopulmonary bypass (32 °C) was instituted with femoral artery and right atrium cannulation. Femoral artery cannulation was preferred in order to achieve a more distal cross-clamping site on the ascending aorta. Myocardial protection was achieved by combination of antegrade and retrograde Custodiol cardioplegic solution and topical cooling with 4 °C saline solution.
All patients but three, underwent the reimplantation of the aortic valve according to the technique described by David [1]. The sinuses and the ascending aorta were excised so that only 3 to 4 mm of the aortic wall were left attached to the annulus. The coronary ostia were prepared for a button reimplantation as for a conventional root-replacement procedure [5]. In the presence of a bicuspid valve, radial tension was placed on the 2 commissures by means of two sutures in order to assess leaflet prolapse. The free margin of congenital fusion of the left and right coronary leaflets was found to be elongated in 2 cases. Shortening of the free margin was achieved by a plication of the margin itself with a Gore-Tex 6-0 running suture. Shortening of the leaflet margin was considered adequate if both leaflets were at identical heights after applying radial tension on the two commissures. Then, 4-0 polypropylene sutures were placed from the inside to the outside around the aortic annulus along a horizontal plane below the valve leaflets level. Prosthesis diameters were calculated from the diameter of the left ventricular outflow tract and the height of the aortic cusps. In all the 29 reimplantation procedures the Gelweave Valsalva prosthesis (Sulzer Vascutek, Renfrewshire, Scotland) [7,8] was implanted. The diameter of the graft was equal or slightly smaller than the average length of the free margins of the aortic cusps [1]. The coronary arteries were then implanted and the graft was anastomosed to the distal aorta in a conventional way.
Three patients with ascending aorta aneurysms and isolated non-coronary aortic sinus dilatation underwent the remodeling procedure [4]. The non-coronary sinus and the ascending aorta were replaced by a scalloped shape dacron tubular graft (Sulzer Vascutek, Renfrewshire, Scotland).
The graft size was 28 millimetres (mm) in 4 (13%) patients, 30 mm in 13 (40%) and 32 mm in 15 (47%).
A transesophageal echocardiogram (TEE) was carried out intraoperatively in all the patients after the cardiopulmonary bypass weaning in order to evaluate the competence of the aortic valve. None of the patients showed AI grater than mild.
Table 2 shows the operative data.
3. Results
All patients underwent the operation during a recent 18-month period.
There were no intraoperative deaths. One patient showed ischemia at the electrocardiogram soon after the cardiopulmonary bypass weaning; an intraoperative TEE showed a hypokinetic left ventricular posterior wall. A kinking at the right coronary ostium site was noted. After a venous graft on the right coronary was performed, the patient recovered completely and did not develop myocardial infarction (creatinine phosphokinase <300 IU/l, myocardial band <5%). Three patients required early reoperation (<24 h) for bleeding. Two patients underwent pacemaker implantation because of permanent atrioventricular block.
3.1. Aortic valve function
All the patients underwent two-dimensional echocardiogram at discharge. Colour flow Doppler was used to detect AI, and severity was subjectively graded as trivial (1+), mild (2+), moderate (3+) and severe (4+).
There was no or trivial (1+) AI in 17 (52%) patients; 13 (42%) had a mild (2+) AI and 2 (6%) had severe (4+) AI requiring mechanical aortic valve replacement respectively 4 and 6 weeks after the aortic valve reimplantation procedure. The first patient was a 28-year-old man with Marfan syndrome, the second, with a bicuspid aortic valve, had during the first operation a prolapsing cusp repair by shortening of the free margin.
Two more patients required reoperation for non-valve related complications. One patient developed a pseudoaneurysm for a leak at the left coronary anastomosis 1 month after the first operation; the second developed a constrictive pericarditis three months after the first procedure. Both of them recovered completely after the reoperation.
4. Discussion
The mechanisms that lead to AI in patients with aortic root and/or ascending aorta aneurysms are nowadays well known [9–11]. The conventional treatment of these patients consists of aortic root replacement with a composite graft. Many series [12,13] showed that this operation is safe and has a low mortality and morbidity rate. However, most of these patients arrive for the operation with intact or minimally stretched aortic cusps. Why should one remove an anatomically normal aortic valve This is the question that Sarsam, Yacoub and David asked themselves approximately a decade ago. Sarsam and Yacoub [14] proposed the remodeling technique of the aortic root to achieve cusps coaptation by reduction of the sinotubular junction. This approach preserves the anatomy and the function of the sinuses of Valsalva; this step is considered essential in order to avoid cusps trauma and degeneration, but does not provide stabilization of the annulus with a tendency towards progressive AI [15]. We did not use this technique in our series. This aspect was addressed by David and Feindel [1]; they found that in many patients with sinotubular dilatation, it also co-exists annulus dilatation. This is particularly evident in patients with connective tissues disorders, such as the Marfan syndrome [16]. They proposed the reimplantation technique to provide stabilization of the aortic annulus, better support of the aortic wall and less chance of suture bleeding.
Nevertheless, we have to admit that one of the two patients of our series, a young man with Marfan syndrome, who underwent reoperation for severe AI, had originally a reimplantation procedure and did not benefit from it. This technique, however, does not preserve the anatomy and the function of the sinuses of Valsalva. This issue was addressed by De Paulis [7,8], introducing modified Dacron conduit (Gelweave Valsalva, Sulzer Vascutek, Renfrewshire, Scotland) that on implantation recreates sinuses of Valsalva of normal shape and dimension, providing a sufficient gap that should avoid any contact between the open leaflet and the Dacron wall. Longer follow-up is needed in order to assess the cusps preservation. We used this prosthesis in all the patients who underwent aortic valve reimplantation in our series.
Langer and colleagues [17] showed that the addition of leaflet prolapse repair to root replacement does not result in increased morbidity or hospital mortality. Our experience in cusp repair is very limited; we used the free margin shortening technique just in two patients, but one of them, with a bicuspid aortic valve, rapidly developed severe AI and underwent reoperation. The TEE carried out before reoperation showed a central jet through the valve. The valve, in fact, turned out to have a central gap caused by the retraction of the cusp presenting a raphe. Was the raphe fibrosis the cause of the cusp retraction Was our approach in shortening the free margin too aggressive We are still not able to answer these questions, but since our approach consists of triangular resection of the raphe [18] in case of prolapsing bicuspid aortic valve. It has been shown that reconstruction of the regurgitant bicuspid valve by means of triangular resection of a median raphe, in combination with proximal aortic replacement provides good midterm results [2]. Although the current results are promising, further follow-up will be required in order to determine the reliability of this technique in the long term.
In our series there were no deaths and the freedom from moderate or severe AI at discharge was 94%; we thus conclude that the valve-sparing operations have, in our short experience, a low morbidity rate especially in patients with tricuspid aortic valve. We moreover think that the optimal technique of leaflet repair is still open to controversy.
References
David TE and Feindel CM. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovasc Surg 1992;103:617–621.
Schafers H, Aicher D, Langer F. Correction of leaflet prolapse in valve-preserving aortic replacement: Pushing the limits Ann Thorac Surg 2002;74:S1762–S1764.
El Koury 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.
David TE, Feindel CM, Bos J. Repair of the aortic valve in patients with aortic insufficiency and aortic root aneurysm. J Thorac Cardiovasc Surg 1995;109:345–351.
Bentall H and De Bono A. A technique for complete replacement of the ascending aorta. Thorax 1968;23:338–339.
Gott VL, Laschinger JC, Cameron DE, Dietz HC, Greene PS, Gillinov AM, Pyeritz RE, Alejo DE, Fleischer KJ, Anhalt GJ, Stone CD, McKusick VA. The Marfan syndrome and the cardiovascular surgeon. Eur J Cardiothorac Surg 1996;10:149–158.
De Paulis R, De Matteis GM, Nardi P, Scaffa R, Buratta MM, Chiariello L. Opening and closing characteristics of the aortic valve after valve-sparing procedures using a new aortic root conduit. Ann Thorac Surg 2001;72:487–494.
De Paulis R, De Matteis GM, Nardi P, Scaffa R, Colella DF, Chiarello L. A new aortic Dacron conduit for surgical treatment of aortic root pathology. Ital Heart J 2000;1:457–463.
Bellhouse BJ, Bellhouse F, Abbott JA, Talbot L. Mechanism of valvular incompetence in aortic sinus dilatation. Cardiovasc Res 1973;7:490–494.
Kunzelman KS, Grande KJ, David TE, Cochran RP, Verrier ED. Aortic root and valve relationships. Impact on surgical repair. J Thorac Cardiovasc Surg 1994;107:162–170.
Reid K. The anatomy of the sinus of Valsalva. Thorax 1970;25:79–85.
Dossche KM, Schepens MA, Morshuis WJ, de la Riviere AB, Knaepen PJ, Vermeulen FE. A 23-year experience with composite valve graft replacement of the aortic root. Ann Thorac Surg 1999;67:1070–1077.
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.
Sarsam MA and Yacoub M. Remodeling of the aortic valve anulus. J Thorac Cardiovasc Surg 1993;105:435–438.
Yacoub M, Gehle P, Chandrasekaran V, Birks EJ, Child A, Radley-Smith R. Late results of a valve preserving operation in patients with aneurysms of the ascending aorta and root. J Thorac Cardiovasc Surg 1998;115:1080–1090.
Roman MJ, Rosen SE, Kramer-Fox R, Devereux RB. Prognostic significance of the pattern of aortic root dilation in the Marfan syndrome. J Am Coll Cardiol 1993;22:1470–1476.
Langer F, Graeter T, Nikoloudakis N, Aicher D, Wendler O, Schafers HJ. Valve-preserving aortic replacement: does the additional repair of leaflet prolapse adversely affect the results J Thorac Cardiovasc Surg 2001;122:270–277.
Cosgrove DM, Rosenkranz ER, Hendren WG, Bartlett JC, Stewart WJ. Valvuloplasty for aortic insufficiency. J Thorac Cardiovasc Surg 1991;102:571–576.(Fabrizio Settepani, Diego)
Presented at the 53rd International Congress of the European Society for the Cardiovascular Surgery, Ljubjana, Slovenia, June 2–5, 2004.
Abstract
Objective: Aortic valve-sparing operations were developed to preserve the native aortic valve in patients with aneurysms of the aortic root or ascending aorta and normal aortic valve leaflets. This paper describes our initial experience with valve-sparing operations and early clinical and echocardiographic results obtained. Methods: From October 2002 to March 2004, 32 consecutive patients underwent aortic valve-sparing operations at the Istituto Clinico Humanitas, Rozzano, Italy. Preoperative transesophageal echocardiography showed moderate or severe aortic incompetence (AI) in 15 patients (47%). Twenty-nine patients underwent reimplantation of the aortic valve and 3 patients remodeling of one sinus. In 2 cases prolapsing cusp repair was carried out. Results: There were no intraoperative deaths. At discharge, two-dimensional echocardiogram showed no or trivial aortic incompetence (AI) in 17 (52%) patients and mild AI in 13 (42%); 2 (6%) patients had severe AI requiring reoperation, respectively 4 and 6 weeks later. Conclusions: The valve-sparing procedures showed good preliminary results, thus encouraging further use of this type of repair. However, further larger studies and long-term results are needed in order to define the durability of these techniques.
Key Words: Aortic valve leaflets; Valve-sparing operations; Aortic root
1. Introduction
Aortic valve-sparing operations were developed to preserve the native aortic valve in patients with aneurysms of the aortic root or ascending aorta and normal aortic valve leaflets [1]; in recent years indications have been extended also to valves having cusps without gross structural defects [2,3]. These kind of aneurysms are frequently associated with aortic incompetence (AI) which is caused by loss of the sino-tubular junction, dilatation or distortion of one or more sinuses of Valsalva, annuloaortic ectasia or a combination of these problems [4]. The conventional treatment consists of composite replacement of the aortic valve and the ascending aorta [5]; though it’s considered ‘safe’, it is not free from complications including thromboembolism, endocarditis, and long-term anticoagulation related problems [6]. Then, from October 2002, we have adopted valve-sparing operations to treat patients with root dilatation and aortic cusps without gross structural defects.
This paper describes our initial experience with valve-sparing operations and early clinical and echocardiographic results obtained.
2. Material and methods
From October 2002 to March 2004, 32 consecutive patients underwent aortic valve-sparing operations at the Istituto Clinico Humanitas, Rozzano, Italy. Our standard indications have been aneurysms of the aortic root and/or ascending aorta and aortic cusps without gross structural defects. The final decision to preserve the valve was made intraoperatively by the surgeon after inspection of valve cusps and root geometry. When the structural defects of the cusps were considered unsuitable for repair the Bentall procedure was performed. Demographic data are listed in Table 1. Patients were predominantly male and mean age was 58 ±13 (range 28–83). The mean ascending aorta diameter was 5.1±1.1 cm. Among the patients with no, trivial or mild AI the mean ascending aorta diameter was 5.0±1.0 cm and of these 33.3% had a bicuspid aortic valve.
2.1. Operative techniques
A median sternotomy was performed and hypothermic cardiopulmonary bypass (32 °C) was instituted with femoral artery and right atrium cannulation. Femoral artery cannulation was preferred in order to achieve a more distal cross-clamping site on the ascending aorta. Myocardial protection was achieved by combination of antegrade and retrograde Custodiol cardioplegic solution and topical cooling with 4 °C saline solution.
All patients but three, underwent the reimplantation of the aortic valve according to the technique described by David [1]. The sinuses and the ascending aorta were excised so that only 3 to 4 mm of the aortic wall were left attached to the annulus. The coronary ostia were prepared for a button reimplantation as for a conventional root-replacement procedure [5]. In the presence of a bicuspid valve, radial tension was placed on the 2 commissures by means of two sutures in order to assess leaflet prolapse. The free margin of congenital fusion of the left and right coronary leaflets was found to be elongated in 2 cases. Shortening of the free margin was achieved by a plication of the margin itself with a Gore-Tex 6-0 running suture. Shortening of the leaflet margin was considered adequate if both leaflets were at identical heights after applying radial tension on the two commissures. Then, 4-0 polypropylene sutures were placed from the inside to the outside around the aortic annulus along a horizontal plane below the valve leaflets level. Prosthesis diameters were calculated from the diameter of the left ventricular outflow tract and the height of the aortic cusps. In all the 29 reimplantation procedures the Gelweave Valsalva prosthesis (Sulzer Vascutek, Renfrewshire, Scotland) [7,8] was implanted. The diameter of the graft was equal or slightly smaller than the average length of the free margins of the aortic cusps [1]. The coronary arteries were then implanted and the graft was anastomosed to the distal aorta in a conventional way.
Three patients with ascending aorta aneurysms and isolated non-coronary aortic sinus dilatation underwent the remodeling procedure [4]. The non-coronary sinus and the ascending aorta were replaced by a scalloped shape dacron tubular graft (Sulzer Vascutek, Renfrewshire, Scotland).
The graft size was 28 millimetres (mm) in 4 (13%) patients, 30 mm in 13 (40%) and 32 mm in 15 (47%).
A transesophageal echocardiogram (TEE) was carried out intraoperatively in all the patients after the cardiopulmonary bypass weaning in order to evaluate the competence of the aortic valve. None of the patients showed AI grater than mild.
Table 2 shows the operative data.
3. Results
All patients underwent the operation during a recent 18-month period.
There were no intraoperative deaths. One patient showed ischemia at the electrocardiogram soon after the cardiopulmonary bypass weaning; an intraoperative TEE showed a hypokinetic left ventricular posterior wall. A kinking at the right coronary ostium site was noted. After a venous graft on the right coronary was performed, the patient recovered completely and did not develop myocardial infarction (creatinine phosphokinase <300 IU/l, myocardial band <5%). Three patients required early reoperation (<24 h) for bleeding. Two patients underwent pacemaker implantation because of permanent atrioventricular block.
3.1. Aortic valve function
All the patients underwent two-dimensional echocardiogram at discharge. Colour flow Doppler was used to detect AI, and severity was subjectively graded as trivial (1+), mild (2+), moderate (3+) and severe (4+).
There was no or trivial (1+) AI in 17 (52%) patients; 13 (42%) had a mild (2+) AI and 2 (6%) had severe (4+) AI requiring mechanical aortic valve replacement respectively 4 and 6 weeks after the aortic valve reimplantation procedure. The first patient was a 28-year-old man with Marfan syndrome, the second, with a bicuspid aortic valve, had during the first operation a prolapsing cusp repair by shortening of the free margin.
Two more patients required reoperation for non-valve related complications. One patient developed a pseudoaneurysm for a leak at the left coronary anastomosis 1 month after the first operation; the second developed a constrictive pericarditis three months after the first procedure. Both of them recovered completely after the reoperation.
4. Discussion
The mechanisms that lead to AI in patients with aortic root and/or ascending aorta aneurysms are nowadays well known [9–11]. The conventional treatment of these patients consists of aortic root replacement with a composite graft. Many series [12,13] showed that this operation is safe and has a low mortality and morbidity rate. However, most of these patients arrive for the operation with intact or minimally stretched aortic cusps. Why should one remove an anatomically normal aortic valve This is the question that Sarsam, Yacoub and David asked themselves approximately a decade ago. Sarsam and Yacoub [14] proposed the remodeling technique of the aortic root to achieve cusps coaptation by reduction of the sinotubular junction. This approach preserves the anatomy and the function of the sinuses of Valsalva; this step is considered essential in order to avoid cusps trauma and degeneration, but does not provide stabilization of the annulus with a tendency towards progressive AI [15]. We did not use this technique in our series. This aspect was addressed by David and Feindel [1]; they found that in many patients with sinotubular dilatation, it also co-exists annulus dilatation. This is particularly evident in patients with connective tissues disorders, such as the Marfan syndrome [16]. They proposed the reimplantation technique to provide stabilization of the aortic annulus, better support of the aortic wall and less chance of suture bleeding.
Nevertheless, we have to admit that one of the two patients of our series, a young man with Marfan syndrome, who underwent reoperation for severe AI, had originally a reimplantation procedure and did not benefit from it. This technique, however, does not preserve the anatomy and the function of the sinuses of Valsalva. This issue was addressed by De Paulis [7,8], introducing modified Dacron conduit (Gelweave Valsalva, Sulzer Vascutek, Renfrewshire, Scotland) that on implantation recreates sinuses of Valsalva of normal shape and dimension, providing a sufficient gap that should avoid any contact between the open leaflet and the Dacron wall. Longer follow-up is needed in order to assess the cusps preservation. We used this prosthesis in all the patients who underwent aortic valve reimplantation in our series.
Langer and colleagues [17] showed that the addition of leaflet prolapse repair to root replacement does not result in increased morbidity or hospital mortality. Our experience in cusp repair is very limited; we used the free margin shortening technique just in two patients, but one of them, with a bicuspid aortic valve, rapidly developed severe AI and underwent reoperation. The TEE carried out before reoperation showed a central jet through the valve. The valve, in fact, turned out to have a central gap caused by the retraction of the cusp presenting a raphe. Was the raphe fibrosis the cause of the cusp retraction Was our approach in shortening the free margin too aggressive We are still not able to answer these questions, but since our approach consists of triangular resection of the raphe [18] in case of prolapsing bicuspid aortic valve. It has been shown that reconstruction of the regurgitant bicuspid valve by means of triangular resection of a median raphe, in combination with proximal aortic replacement provides good midterm results [2]. Although the current results are promising, further follow-up will be required in order to determine the reliability of this technique in the long term.
In our series there were no deaths and the freedom from moderate or severe AI at discharge was 94%; we thus conclude that the valve-sparing operations have, in our short experience, a low morbidity rate especially in patients with tricuspid aortic valve. We moreover think that the optimal technique of leaflet repair is still open to controversy.
References
David TE and Feindel CM. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovasc Surg 1992;103:617–621.
Schafers H, Aicher D, Langer F. Correction of leaflet prolapse in valve-preserving aortic replacement: Pushing the limits Ann Thorac Surg 2002;74:S1762–S1764.
El Koury 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.
David TE, Feindel CM, Bos J. Repair of the aortic valve in patients with aortic insufficiency and aortic root aneurysm. J Thorac Cardiovasc Surg 1995;109:345–351.
Bentall H and De Bono A. A technique for complete replacement of the ascending aorta. Thorax 1968;23:338–339.
Gott VL, Laschinger JC, Cameron DE, Dietz HC, Greene PS, Gillinov AM, Pyeritz RE, Alejo DE, Fleischer KJ, Anhalt GJ, Stone CD, McKusick VA. The Marfan syndrome and the cardiovascular surgeon. Eur J Cardiothorac Surg 1996;10:149–158.
De Paulis R, De Matteis GM, Nardi P, Scaffa R, Buratta MM, Chiariello L. Opening and closing characteristics of the aortic valve after valve-sparing procedures using a new aortic root conduit. Ann Thorac Surg 2001;72:487–494.
De Paulis R, De Matteis GM, Nardi P, Scaffa R, Colella DF, Chiarello L. A new aortic Dacron conduit for surgical treatment of aortic root pathology. Ital Heart J 2000;1:457–463.
Bellhouse BJ, Bellhouse F, Abbott JA, Talbot L. Mechanism of valvular incompetence in aortic sinus dilatation. Cardiovasc Res 1973;7:490–494.
Kunzelman KS, Grande KJ, David TE, Cochran RP, Verrier ED. Aortic root and valve relationships. Impact on surgical repair. J Thorac Cardiovasc Surg 1994;107:162–170.
Reid K. The anatomy of the sinus of Valsalva. Thorax 1970;25:79–85.
Dossche KM, Schepens MA, Morshuis WJ, de la Riviere AB, Knaepen PJ, Vermeulen FE. A 23-year experience with composite valve graft replacement of the aortic root. Ann Thorac Surg 1999;67:1070–1077.
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.
Sarsam MA and Yacoub M. Remodeling of the aortic valve anulus. J Thorac Cardiovasc Surg 1993;105:435–438.
Yacoub M, Gehle P, Chandrasekaran V, Birks EJ, Child A, Radley-Smith R. Late results of a valve preserving operation in patients with aneurysms of the ascending aorta and root. J Thorac Cardiovasc Surg 1998;115:1080–1090.
Roman MJ, Rosen SE, Kramer-Fox R, Devereux RB. Prognostic significance of the pattern of aortic root dilation in the Marfan syndrome. J Am Coll Cardiol 1993;22:1470–1476.
Langer F, Graeter T, Nikoloudakis N, Aicher D, Wendler O, Schafers HJ. Valve-preserving aortic replacement: does the additional repair of leaflet prolapse adversely affect the results J Thorac Cardiovasc Surg 2001;122:270–277.
Cosgrove DM, Rosenkranz ER, Hendren WG, Bartlett JC, Stewart WJ. Valvuloplasty for aortic insufficiency. J Thorac Cardiovasc Surg 1991;102:571–576.(Fabrizio Settepani, Diego)