Ann Thorac Surg 2001;71:S249-S252
© 2001 The Society of Thoracic Surgeons
Valvular bioprostheses over 15 years
Experience with the 19-mm Carpentier-Edwards pericardial bioprosthesis in the elderly
Michel Carrier, MDa,
Michel Pellerin, MDa,
Louis P. Perrault, MD, PhDa,
Yves Hébert, MDa,
Pierre Pagé, MDa,
Raymond Cartier, MDa,
Ihor Dyrda, MDa,
L. Conrad Pelletier, MDa
a Department of Surgery and Medicine, Montreal Heart Institute, and the University of Montreal, Montreal, Quebec, Canada
Address reprint requests to Dr Carrier, Department of Surgery, Montreal Heart Institute, Research Center, 5000 Belanger St East, Montreal, PQ, Canada H1T 1C8
e-mail: carrier{at}icm.umontreal.ca
Presented at the VIII International Symposium on Cardiac Bioprostheses, Cancun, Mexico, Nov 3–5, 2000.
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Abstract
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Background. Valve replacement in small aortic root remains a surgical challenge. The objective of this study was to compare results of the 19-mm bioprosthesis with those of larger prostheses in the elderly.
Methods. The 443 patients, 70 years of age and older, who underwent aortic valve replacement with Carpentier-Edwards pericardial bioprostheses were reviewed.
Results. There were 93 patients with a mean age of 76 ± 4 years with implantation of 19-mm prostheses and 350 patients with a mean age of 75 ± 4 years with larger bioprostheses. Associated aortoplasty was performed in 10 patients (11%) with 19-mm bioprostheses and in 8 patients (2%) with larger bioprostheses (p = 0.001). There were 11 deaths (12%) within 30 days of surgery in patients with 19-mm prostheses and 22 deaths (6%) among those with larger prostheses (p = 0.1). The 7-year survival rate averaged 61% ± 7% in patients with 19-mm prostheses and 67% ± 4% in those with larger prostheses (p = 0.8). The 7-year freedom rates from all valve-related events averaged 96% ± 2% and 93% ± 2%, respectively (p = 0.6).
Conclusions. Aortic valve replacement with the 19-mm Carpentier-Edwards pericardial bioprosthesis offers excellent midterm results in the elderly.
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Introduction
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Several techniques of annular enlargement have been proposed for patients with small aortic root, but the use of a small aortic prosthesis remains an option especially in the elderly. Although the impact of prosthesis-patient mismatch has been well described [1], the use of a patch enlargement of the aortic annulus with a larger prosthesis remains controversial. Sommers and David [2] reported that aortic annulus enlargement techniques double the operative mortality of aortic valve replacement. The newer stentless bioprostheses have been proposed for valve replacement in small aortic roots, but midterm and long-term durability remain unknown [3, 4]. Moreover, implantation of a stentless bioprosthesis in a small calcified aortic root associated with coronary artery bypass grafting (CABG) in an elderly patient remains a difficult surgical challenge.
Because of the increase in operative mortality with patch enlargement techniques and because of the unknown midterm durability of stentless valves, we have used small prostheses when indicated for aortic valve replacement in the elderly. The objective of the present study was to compare results of the 19-mm Carpentier-Edwards pericardial bioprosthesis with those of larger prostheses implanted in the elderly patients at the Montreal Heart Institute.
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Material and methods
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Medical records of 443 patients of 70 years of age and older who underwent aortic valve replacement with Carpentier-Edwards bovine pericardial bioprostheses between 1981 and 1999 were reviewed. All patients were prospectively followed at the Montreal Heart Institute valve clinic with a follow-up visit at annual intervals. The follow-up was complete in all except 3 patients (99%).
Valve-related complications are reported according to the Guidelines of the Ad Hoc Liaison Committee of The Society of Thoracic Surgeons and The American Association of Thoracic Surgery [5].
The data are presented as mean and standard deviation. Differences between groups were analyzed using the Student’s t test or Fisher’s exact test. Analyses of survival and event-free survival (thromboembolism, endocarditis, valve replacement, all valve-related complication) were performed with the Kaplan-Meier method and the log-rank test. Proportional hazards regression was used to study the influence of covariates (age, sex, valve size, associated CABG, associated aortoplasty, and reoperation) and the 7-year mortality after aortic valve replacement. Statistical significance was established at p less than 0.05.
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Results
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Characteristics of patients
There were 80 women (86%) and 13 men (14%), with a mean age of 76 ± 4 years, who underwent implantation of 19-mm prostheses compared with 123 women (35%) and 227 men (65%; p = 0.001), with a mean age of 75 ± 4 years (p = 0.2), who underwent implantation of larger bioprostheses sizes 21 to 31 (Table 1). Associated polyethylene terephthalate fiber (Dacron) or pericardial patch enlargement aortoplasty and septal myectomy was performed in 10 patients (11%) with 19-mm bioprostheses compared with 8 patients (2%) in the larger bioprostheses group (p = 0.001). Associated CABG was also performed in 31 patients (33%) undergoing implantation of 19-mm bioprostheses and in 140 patients (40%) with larger prostheses (p = 0.3).
Immediate and long-term survival
Overall, there were 11 deaths (12%) within 30 days of operation in patients with 19-mm prostheses and 22 deaths (6%) among those with larger prostheses (p = 0.1). The 7-year actuarial survival rate averaged 61% ± 7% in patients with 19-mm prostheses compared with 67% ± 4% in those with larger prostheses (p = 0.8; Fig 1).
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Fig 1. Actuarial survival rates with early deaths included. (19-mm prostheses = patients who underwent implantation of 19-mm prostheses; Larger Prostheses = patients who underwent implantation of  21-mm prostheses.)
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Among patients who underwent isolated aortic valve replacement, there were 3 deaths (among 58 patients, 5%) within 30 days of operation with 19-mm prostheses compared with 11 deaths (among 203 patients, 5%) among those with larger prostheses (p = 0.9). The 7-year actuarial survival rate averaged 73% ± 9% in patients with isolated aortic valve replacement using 19-mm prostheses compared with 71% ± 5% in those with larger prostheses (p = 0.4; Fig 2).
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Fig 2. Actuarial survival rates of patients who underwent isolated aortic valve replacement. (19-mm prostheses = patients who underwent implantation of 19-mm prostheses; Larger Prostheses = patients who underwent implantation of 21-mm prostheses.)
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Long-term results
The 7-year actuarial freedom rates from thromboembolic events and from endocarditis was 100% in patients with 19-mm prostheses compared with 96% ± 2% and 97% ± 1% in those with larger prostheses, respectively (p = 0.9 and p = 0.2). The 7-year actuarial freedom rate from reoperation and from all valve-related events averaged 91% ± 9% in patients with 19-mm prostheses and 97% ± 1% and 95% ± 2% among those with larger prostheses, respectively (p = 0.6 and p = 0.6; Fig 3).
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Fig 3. Actuarial freedom rates from all-valve-related complications. (19-mm prostheses = patients who underwent implantation of 19-mm prostheses; Larger Prostheses = patients who underwent implantation of 21-mm prostheses.)
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In a multivariate analysis, patient’s age (odds ratio, 1.07; 95% confidence interval, 1.05 to 1.1), associated CABG (odds ratio, 1.6; 95% confidence interval, 1.4 to 1.8), associated enlargement aortoplasty (odds ratio, 2.4; 95% confidence interval, 2 to 2.8), and male sex (odds ratio, 1.5; 95% confidence interval, 1.2 to 1.7) were the four risk factors most correlated with the 7-year mortality after aortic valve replacement. The size of prosthesis was not associated with long-term mortality in these elderly patients (p = 0.2).
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Comment
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In the present study, we have shown that elderly patients with small aortic root who underwent implantation of 19-mm Carpentier-Edwards pericardial prostheses had similar long-term survival and event-free survival compared with those who underwent implantation of larger prostheses. Eighty-six percent of patients with 19-mm prostheses were women, and 10% underwent patch enlargement of the aortic root or myectomy associated with aortic valve replacement. The associated aortoplasty explains in part the higher 30-day mortality shown in the later groups. A multivariate analysis identifies age, male sex, associated CABG, and aortoplasty as significant risk factors for the 7-year mortality after aortic valve replacement. The use of small 19-mm prostheses was not a risk factor for mortality in this analysis. However, it must be pointed out that annulus enlargement was needed in some patients of this group to implant a 19-mm valve. This shows the extremely small annulus in these patients, which may have been responsible for the increased surgical risk of early mortality.
Sommers and David [2] reported that operative mortality was twice as high with path enlargement of the aortic annulus compared with isolated aortic valve replacement in middle-aged patients. Although hospital mortality was increased with aortic annulus enlargement, they recommend these techniques to prevent patient-prosthesis mismatch. We suggest that, except for the extremely small annulus, there is no significant advantage to the use of an annulus enlargement technique in elderly patients in whom hospital mortality could be even higher than previously reported by Sommers and David [2] without a significant benefit in midterm survival and in survival free from valve-related complications.
Contrary to Adams and colleagues [6], who suggested that operative mortality was higher in men than in women with a 19-mm prosthesis, the 30-day mortality was similar between men and women (2 of 13, 15% versus 9 of 80, 11%, respectively; p = 0.6) in the present study. Moreover, we found that associated procedures, CABG and patch enlargement of aortic annulus, are responsible for the higher operative mortality found in patients undergoing implantation of a 19-mm prosthesis. The 30-day mortality for isolated aortic valve replacement averaged 5% both in patients with 19-mm prostheses and in those with larger prostheses. Thus, small elderly male patients with an aortic annulus size of 19 mm are good candidates for 19-mm Carpentier-Edwards bioprostheses, whereas with a smaller native aortic annulus, enlargement becomes mandatory.
Excellent results have been obtained with several mechanical prostheses in small aortic root [7]. Sawant and colleagues [8] observed that 60% of patients with 19-mm St. Jude mechanical valves survived 10 years after valve replacement and that there was no relationship between survival and patient-prosthesis mismatch. Fiore and colleagues [9], in a prospective trial, did not detect a difference in the performance of the St. Jude and the Medtronic Hall small valves.
We have shown that the Carpentier-Edwards pericardial bioprosthesis offers good results 15 years after valve replacement [10]. Moreover, the hemodynamic performance of the prosthesis compares favorably with the Medtronic Freestyle aortic bioprosthesis. The 19-mm Carpentier-Edwards bioprosthesis had a gradient at rest of 24 mm Hg and an effective orifice area of 1 cm2 compared with 1.15 cm2 in a patient with a 19-mm Freestyle bioprosthesis [11]. Izzat and colleagues [12], in studying aortic prostheses using dobutamine stress echocardiography, have shown that patient-prosthesis mismatch is not a problem of clinical significance with the St. Jude and the Carbomedics prostheses. The relationship between body surface area of the patient, the level of physical activity, and valve size determines the transvalvular gradient and the effective orifice area of the prosthesis, which remains poorly correlated with the long-term survival after aortic valve replacement with newer bileaflet mechanical valves and several bioprostheses [13]. Khan and colleagues [14] studied a group of 41 elderly patients 18 months after aortic valve replacement with 19-, 21-, and 23-mm Carpentier-Edwards pericardial valves and found mean gradients from 16 to 22 mm Hg, valve orifice areas from 1.1 to 1.5 cm2 associated with significant reduction in left ventricular mass indexes when compared with preoperative values.
Although patient-prosthesis mismatch remains a constant concern in selecting a prosthesis, especially in patients with small aortic root, aortic valve replacement with the 19-mm Carpentier-Edwards pericardial bioprosthesis offers excellent midterm results and remains a valuable alternative to aortic root enlargement techniques and to small stentless valves in the elderly. With a smaller native annulus that will not admit a 19-mm valve, enlargement must be performed but at the expanse of an increased risk.
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References
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Sommers K.E., David T.E. Aortic valve replacement with patch enlargement of the aortic annulus. Ann Thorac Surg 1997;63:1608-1612.
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Hvass U., Palatianos G.M., Frassani R., Puricelli C., O’Brien M. Multicenter study of stentless valve replacement in the small aortic root. J Thorac Cardiovasc Surg 1999;117:267-272.
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Sintek C.F., Fletcher A.D., Khonsari S. Small aortic root in the elderly: use of stentless bioprosthesis. J Heart Valve Dis 1996;5(Suppl):S308-S313.
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Edmunds L.H., Jr, Clark R.E., Cohn L.H., Grunkemeier G.L., Miller D.C., Weisel R.D. Guidelines for reporting morbidity and mortality after cardiac valvular operations. Ann Thorac Surg 1996;62:932-935.
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Adams D.H., Chen R.H., Kadner A., Aranki S.F., Allred E.N., Cohn L.H. Impact of small prosthetic valve size on operative mortality in elderly patients after aortic valve replacement for aortic stenosis: does gender matter?. J Thorac Cardiovasc Surg 1999;118:815-822.
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Franzen S.F., Huljebrant I.E., Konstantinov I.E., Nylander E., Olin C.L. Aortic valve replacement for aortic stenosis in patients with small aortic root. J Heart Valve Dis 1996;5(Suppl):S284-S288.
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Sawant D., Singh A.K., Feng W.C., Bert A.A., Rotenberg F. Nineteen-millimeter aortic St. Jude Medical heart valve prosthesis: up to sixteen years’ follow-up. Ann Thorac Surg 1997;63:964-970.
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Fiore A.C., Swartz M., Grunkemeier G., et al. Valve replacement in the small aortic annulus: prospective randomized trial of St. Jude with Medtronic Hall. Eur J Cardiothorac Surg 1997;11:485-491.
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Poirier N.C., Pelletier L.C., Pellerin M., Carrier M. 15-year experience with the Carpentier-Edwards pericardial bioprosthesis. Ann Thorac Surg 1998;66:S57-S61.
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Dumesnil J.G., LeBlanc M.H., Cartier P.C., et al. Hemodynamic features of the Freestyle aortic bioprosthesis compared with stented bioprosthesis. Ann Thorac Surg 1998;66:S130-S133.
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Izzat M.B., Kadir I., Reeves B., Wilde P., Bryan A.J., Angelini G.D. Patient-prosthesis mismatch is negligible with modern small-size aortic valve prostheses. Ann Thorac Surg 1999;68:1657-1660.
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Pibarot P., Dumesnil J.G., Jobin J., Cartier P., Honos G., Durand L.G. Hemodynamic and physical performance during maximal exercise in patients with an aortic bioprosthetic valve. J Am Coll Cardiol 1999;34:1609-1617.
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Khan S.S., Siegel R.J., DeRobertis M.A., et al. Regression of hypertrophy after Carpentier-Edwards pericardial aortic valve replacement. Ann Thorac Surg 2000;69:531-535.
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Abstract
Introduction
