autograft: subcoronary versus intraluminal cylinder or root

Aortic Valve Subcoronary

Replacement With Versus Intraluminal

Allograft/Autograft: Cylinder or Root

Jean E. Rubay, MD, Daniel Raphael, Thierry Sluysmans, MD, Jean-Louis J. Vanoverschelde, MD, Annie Robert, PhD, Jean-Claude Schoevaerdts, MD, Baudouin Marchandise, MD, and Robert A. Dion, MD Divisions

of Cardiothoracic

Surgery,

Cardiology

and

Cardiologic

Pediatry,

University

of Louvain,

Brussels,

Belgium

From April 1990 to May 1994,89 patients (median age, 42 years; range, 10 days to 66 years) underwent aortic valve or root replacement with allografts or autografts. Thirteen patients were less than 18 years old at the time of operation. Indication for aortic valve replacement was aortic stenosis (50 patients, 56%), small stenotic prosthesis (2 patients, 2%), aortic valve endocarditis (19 patients, 21%), isolated aortic regurgitation (17 patients, 19%), and type II truncus arteriosus (1 patient, 1%). The subcoronary implantation was used in 45 patients (group A), and implantation of an intraluminal cylinder (16 patients) or complete root replacement (28 patients) was performed in the remaining 44 patients (group B). The Ross procedure was performed in 22 patients. Intraoperative transesophageal echocardiography was used routinely. Five patients died in the early postoperative period (60/c), 2 in group A and 3 in group B. Three other patients required immediate replacement of a failing graft by a mechanical prosthesis (1 in group A and 2 in group 9). There has been no late death. All survivors remained in New York Heart Association functional class I and were free of thromboembolic complications. Endocarditis occurred in

2 patients, 1 year after operation. Both were successfully treated medically. Echocardiographic studies were obtained serially in every patient. Four patients, 2 in group A and 2 in group B underwent reoperation because of mild-to-moderate aortic regurgitation (rate of reoperation, 5%). Two valves were repaired and two were replaced by an allograft. At late echocardiographic follow-up (up to 4 years postoperatively), 22 of 42 patients in group A and 6 of 39 patients in group B showed some degree of aortic regurgitation by color Doppler (p c 0.001). The mean postoperative transvalvular gradient was 12 mm Hg in group A and 6 mm Hg in group B (p < 0.001). It is concluded that aortic valve replacement with either an allograft or an autograft can be performed in both children and adults with a low morbidity and mortality, yielding excellent hemodynamic results. It is suggested that the implantation of an intraluminal cylinder and the complete root replacement might be superior to the subcoronary technique as they result in lower transvalvular gradients and less valvular regurgitation.

T

improving graft durability. The purpose of this study was to review our experience with the use of several different techniques of implantation of these grafts [5].

poor long-term results of the glutaraldehydepreserved xenografts in children and young adults and the risk of systemic anticoagulation after mechanical valve implantation have resulted in a renewed interest in the use of allografts. Allograft replacement of the aortic valve in the subcoronary position was first performed by Ross [l] in 1962 and Barratt-Boyes [2] in 1965. Although initial results were generally good, lacking the complications of thromboembolism, hemorrhage, and sudden death associated with mechanical prostheses, the limited availability, as well as problems related to the preservation and storage of these allografts, have delayed their widespread acceptance. Development of cryopreservation techniques in the early 1970s by Angel1 and colleagues [3] has extended the duration for which allografts can be stored safely in liquid nitrogen. More recently, O’Brien and co-workers [4] emphasized the importance of adequate harvesting and preservation techniques in he

Presented Vancouver,

at the VI International Symposium BC, Canada, July 29-31, 1994.

Address reprint requests UCL, avenue HippOCrate,

0 1995 by The

Society

for Cardiac

Bioprosthesis,

to Dr Rubay, Cliniques Universitaires 10, 1200 Brussels, Belgium.

of Thoracic

Surgeons

St-Luc-

(Ann Thorac Surg 1995;6O:S78-82)

Patients

and Methods

Eighty-nine patients (68 men; median age, 42 years; range, 10 days to 66 years) underwent aortic valve replacement by use of an aortic allograft (n = 65), a pulmonary allograft (n = 2), or a pulmonary autograft (n = 22) between April 1990 and May 1994 at the Cliniques Universitaires Saint-Luc, UCL, Brussels, Belgium. The indication for aortic valve replacement was aortic stenosis in 50 patients (56%), small stenotic prosthesis in 2 patients (2X), aortic valve endocarditis in 19 patients (21%), isolated aortic regurgitation in 17 patients (19%), and type II truncus arteriosus in 1 patient (1%). A total of 91 valves were inserted. In 2 patients, both the aortic and the pulmonary valves were replaced. Most allografts (97%) were cryopreserved and processed by the European Homograft Bank in Brussels (Belgium) by use of standard techniques. When cryopreserved valves were unavailable, fresh antibiotic sterilized valves were 0003-4975/95/$9.50 0003-4975(95)00304-4

Ann Thorac Surg 1995;6o:S78-82

ALLOGRAFT

CARDIAC BIOPROSTHESIS ROOT VERSUS SUBCORONARY

RUBAY ET AL IMPLANTATION

s79

used to measure peak and mean aortic valve gradients and to calculate valve areas. Doppler color flow mapping was used to assess the presence and extent of aortic regurgitation. The severity of regurgitation was evaluated qualitatively on a 4-point scale from 0 (absent) to 4 (severe).

Statistical Analysis Results are expressed as mean t one standard deviation. Differences between groups were evaluated by use of the Fisher’s exact test for categorical variables and by use of the Student’s f test for unpaired data for continuous variables. All tests were two-tailed and p values less than 0.05 were considered indicative of a statistically significant difference. Survival were analyzed by the nonparametric actuarial method of Kaplan-Meier 181. Fig 1. The three diflerent surgical plantation (top left), intraluminal

placement

techniques cylinder

used:

subcoronary imroot re-

(bottom), and

(top right).

used (n = 13). The diameter of aortic allografts ranged between 12 and 27 mm (mean, 23 mm) and between 17 and 27 mm (mean, 23 mm) for the pulmonary allografts in the Ross procedures [6]. The operation was performed through a median sternotomy and cardiopulmonary bypass using a single venous cannula under moderate hypothermia. Myocardial protection was achieved by antegrade or retrograde delivery of a cold crystalloid (St. Thomas II) cardioplegic solution. The aortic grafts were implanted in the subcoronary position in 45 patients (group A) by using the technique proposed by O’Brien and colleagues [5]. Allografts were used as an intraluminal cylinder with reimplantation of the recipient coronary arteries into the valved allograft [7] in 16 patients or for complete aortic root replacement in 28 patients (group B) (Fig 1). The Ross procedure was performed in 22 patients, the autograft being used for either subcoronary implantation (n = 9), as an intraluminal cylinder (n = 8), or for complete root replacement (n = 5). Associated procedures were closure of a ventricular septal defect (2 patients), including one truncus repair, replacement of an heterologous conduit in pulmonary position (1 patient), mitral valve annuloplasty (1 patient), mitral valve commissurotomy (1 patient), and coronary artery bypass grafting by use of the left internal mammary artery (2 patients).

Two-Dimensional

and Doppler Echocardiography

Intraoperative transesophageal echocardiography (TEE) was obtained in all but 3 patients to assess valve morphology and the presence of residual aortic regurgitation. Serial follow-up transthoracic echocardiograms were also obtained at 1 week, 1, 3, 6 months, 1 year, and every year thereafter in every patient for assessment of residual valve stenosis and regurgitation. All examinations were performed by use of the Toshiba SSH-140 echocardiographic system and a 2.5-MHz (TTE) or a ~-MHZ (TEE) transducers. Pulsed- and continuous-wave Doppler was

Results Operative Mortality Five patients died during the early postoperative period (6%). The first patient was a lo-day-old neonate who required emergency balloon valvuloplasty for critical aortic stenosis, resulting in severe aortic regurgitation. He was operated on in critical condition and despite the implantation of a 13-mm aortic allograft (aortoventriculoplasty procedure [9] with reimplantation of the coronary arteries), he died of ventricular failure. The second patient was a 2-month-old baby with a type II truncus and mild aortic regurgitation. The operation consisted of the implantation of an aortic and a pulmonary allograft and closure of the ventricular septal defect. The patient died of right ventricular failure. The third patient was a 13-year-old girl with Turner syndrome associated with aortic coarctation, dilation of the ascending aorta, and mild aortic regurgitation. The aortic valve and ascending aorta were replaced under profound hypothermia and circulatory arrest by use of a 23-mm aortic allograft. During a bronchoscopy aimed at restoring upper airway patency, she sustained a prolonged cardiac arrest and died from cerebral complications. The fourth patient was a 50-year-old man with aortic valve endocarditis and neurologic complications. Despite an uneventful operation, his neurologic status deteriorated rapidly and he died of multiple organ failure. The last patient was a 41-year-old man on immunosuppressive therapy for 11 years for kidney transplantation. He underwent an uneventful allograft replacement of a stenotic aortic valve. One month after operation, acute aortic regurgitation developed, and he died of left ventricular failure. Autopsy could not be obtained.

Immediate lntraoperative

Results

Duration of aortic cross-clamping averaged 125 minutes (range, 62 to 180 minutes) in group A and 123 minutes (range, 87 to 180 minutes) in group B. Intraoperative TEE was performed in all but 3 patients (2 very young and 1 adult). The graft function was normal and no valvular leakage was found in 78 patients. Mild (grade 1) aortic regurgitation was present in 5 group A patients and in 1

S80

CARDIAC BIOPROSTHESIS ALLOGRAFT ROOT VERSUS

RUBAY ET AL SUBCORONARY

Ann Thorac Surg 1995;6O:S78-82

IMPLANTATION

:IL--

25

t 04

0

I 0

2

1

3

Years

Fig 2. The ac-tuuriul

putirllt

sunGill

4

2

1

5

survival

3

4

5

YearS.!WAd Fig 4. The nttuarial

freedom

from

reoperation

at 4 years

was 94%

17t 4 yerlus was 94’%1.

group B patient. Moderate (grade 2) aortic regurgitation was found in 2 patients (one in each group). In one patient with Marfan syndrome, it was attributable to partial dehiscence of the lower suture line, whereas in the other patient, it was related to a distortion of the aortic root resulting in malalignment of the commissures. In both patients, mechanical valves were implanted. A third patient had implantation of a mechanical prosthesis because of the poor quality of a fresh allograft, which resulted in multiple tears and uncontrolled bleeding.

Late Postoperative Results The patients were followed up for a mean of 22 months (range, 1 to 49 months). There has been no late death. The 4-year actuarial survival was 94% (Fig 2) and was similar in both groups. All the 81 survivors were in New York Heart Association functional class 1 and remained free of thromboembolic complications. Endocarditis occurred in 2 patients, 1 year after operation. Both were successfully treated medically. The actuarial freedom from endocarditis was 96”ill (Fig 3). Four patients, 2 in group A and 2 in group B underwent reoperation because of mild-tomoderate aortic regurgitation related to partial dehiscence of the lower suture line in 3 patients, and cusps malalignment in 1 patient. In 2 patients with paravalvular leaks, the valve grafts were repaired 1 month after the

first operation. In the remaining 2 patients, the aortic allografts were replaced with new allografts, 1 year after the first operation. The actuarial freedom from reoperation was 94% (Fig 4). Late follow-up TTE were obtained in all survivors. The peak transvalvular pressure gradient averaged 12 + 6 mm Hg in group A and 6 i 5 mm Hg in group B (p < 0.001; Fig 5). Significant valvular regurgitation (grade 1 or more) was present in 22 of 42 patients in group A (52%) and in 6 of 39 patients in group B (15%, p < 0.001 versus group A). The freedom from aortic regurgitation after 4 years was 26% in group A and 76% in group B (Fig 6). Comment Aortic valve replacement with human aortic allografts has become more prevalent because of the obvious benefits of these materials. Allografts provide superior hemodynamic performance, infrequent thromboembolic and infectious complications, and do not require systemic anticoagulation [lo-121, which makes them particularly attractive for use in children and young adults. In these patients, the Ross procedure may provide a definitive and perhaps ideal solution 113, 141. In the hands of

Pressure Gradient in mmHg

4. 35 30 25 LO 15 10 5

FfEE3mlfran50 bxlazdbs -I 25

..

t

Fig 5. Jhhp mlerugc peak gradient at late folloul-trp group A and 6 mm Hg for group B.

for

was 12 mm Hg

Ann Thorac

Surg ALLOGRAFT

1995;60:S78-82

,._,

PERCENT FREEDOM FROM AORTlC INCOMPETENCE

-m-

GROUP

A

50

the implantation results in relatively In the present study,

of an aortic allow morbidity four of the five

early deaths were not related procedure but rather resulted underlying no late

death

directly to the surgical from the severity of the importance, there has been

disease. and

Of equal the incidence

of

late

complications,

such as thromboembolic events or endocarditis low, consistent with the results of most follow-up published allografts

so far [4,15,161.

on

the use Both early

of fresh and late

studies or cryopreserved graft failures were

infrequently observed and always resulted cal imperfections. Intraoperative graft failure 3 patients,

requiring

aortic

regurgitation

was

from techni-

occurred in of a mechanical pros-

implantation

thesis. Late graft failure occurred who also required reoperation. onset

was quite

in 4 additional

patients,

In each patient, new discovered at echocardiog-

raphy and was not associated with deterioration of the clinical status. It should be pointed out that criteria for patient selection, preservation techniques, tissue compatibility, and other variables known to influence the long-term durability of allografts were not analyzed in this retrospective study, which focused on technical aspects of allograft and autograft implantation. Optimization of these surgical parameters is mandatory to minimize the incidence of valvular leakage and to provide the patient with the best long-term results and the lowest morbidity. In this respect, it is worth mentioning the critical importance of obtaining reliable echocardiograms for accurate preoperative sizing of the host annulus and sinotubular junction and for analysis of the geometry of the aortic ring, which is often grossly disorganized in patients with congenital diseases, redo operations, and endocarditis. Three different techniques were used for allografts and autografts implantation in our study: (1) the subcoronary technique with 120-degree rotation and scalloping of the sinuses;

(2) implantation

(3) complete

aortic

of an intraluminal

root replacement.

cylinder;

and

The last two tech-

niques were compared with the first one. Subcoronarv implantation and implantation of an intraluminal cylinder were favored initially in patients with symmetrical

S81

RUBAY ET AL IMPLANTATION

aortic root, whereas complete aortic root replacement was used in children and in patients with distorted aortic roots, a large annulus, or aortic regurgitation. We started to implant aortic valve allografts in 1990 and autografts in 1991. Our initial results with the subcoronary implantation technique were quite disappointing, as all patients progressively developed some degree of aortic regurgitation. Surprisingly, this did not happen in patients with implantation of an intraluminal cylinder or with complete root replacement. As suggested by McGiffin and O’Brien [17], the subcoronary implantation is far more technically demanding and results more frequently in graft failure because of malalignment of the commissures. Accordingly, we started to favor the two other techniques (ie, the implantation of an intraluminal cylinder whenever the aortic root was symmetrical, and the complete

experienced surgeons, lograft or autograft and mortality rates.

CARDIAC BIOPROSTHESIS ROOT VERSUS SUBCORONARY

aortic

root

replacement

in patients

with

annu-

loectasia, Valsalva aneurysms, or aneurysms or dissection of the ascending aorta). This approach immediately resulted in a reduced incidence of aortic regurgitation at early echocardiographic follow-up and led to the belief that these techniques could prevent the development of regurgitation, although we realize that these encouraging results could have been biased by a short follow-up. In addition to the reduced rates of regurgitation, these techniques were also associated with lower transvalvular gradients (6 mm Hg versus 12 mm Hg with the subcoronary technique). This benefit was mainly seen in the subgroup of patients who had complete aortic root replacement. These results are consistent with those of Daicoff and colleagues [18] and favor the use of the intraluminal cylinder technique or the complete root replacement instead of the subcoronary implantation as initially recommended with these techniques calcification of the

by O’Brien [19]. The only concern is the possibility of progressive graft wall, which could subject the

otherwise well-preserved aortic cusps to additional stress and hence, lead to late graft failure. As this concerns mainly the pediatric patients [20], we would tend to recommend the use of the Ross procedure in these patients as in young adults with a symmetric aortic root.

We are grateful preparation of illustrations.

to Colette Flamand the manuscript and

and Eliane Debecker MichPle Lemaire for

for the

References Ross DN. Homograft replacement of the aortic valve. Lancet 1962;2:487. Barratt-Boyes BG. A method for preparing and inserting a homograft aortic valve. Br J Surg 1965;52:847-56. Angel1 JD, Christopher BS, Hawtrey CO, Angel1 WM. A fresh viable human heart valve bank: sterilization, sterility testing and cryogenic preservation. Transplant Proc 1976; R(Supp1 1):127-U. O’Brien MF, Stafford EG, Gardner MA, Pohlner PG, McGiffin DC. A comparison of aortic valve replacement with viable cryopreserved and fresh allograft valves with a note on chromosomal studies. J Thorac Cardiovasc Surg 1987;94: 812-23.

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Ann Thorac Surg 1995;60:578-82

IMPLANTATION

5. O’Brien MF, McGiffin DC, Stafford EC. Allograft aortic valve implantation: techniques for all types of aortic valve and root pathology. Ann Thorac Surg 1989;48:600-9. Ross DN. Replacement of aortic and mitral valves with a pulmonary autograft. Lancet 1967;2:956-8. Ross DN. Application of homografts in clinical surgery. J Cardiac Surg 1987;2(Suppl):175-82. Kaplan EL, Meier P. Non parametric estimation from incomplete observations. J Am Stat Assoc 1958;53:457-81. Konno S, Imai Y, Lida Y, et al. New method for prosthetic valve replacement in congenital aortic stenosis associated with hypoplasia of the aortic valve ring. J Thorac Cardiovasc Surg 1975;70:909-17. 10. Vesely I, Gonzalez-Lavin L, Graf D, Boughner D. Mechanical testing of cryopreserved aortic allografts comparison with xenografts and fresh tissue. J Thorac Cardiovasc Surg 1990; 99:119-23. 11. McGiffin DC, Galbraith AJ, McLachlan GJ, et al. Aortic valve infection. Risk factors for death and recurrent endocarditis after aortic valve replacement. J Thorac Cardiovasc Surg 1992;104:511-20. 12. Haydock D, Barratt-Boyes B, Macedo T, Kirklin JW, Blackstone E. Aortic valve replacement for active endocarditis in 108 patients. J Thorac Cardiovasc Surg 1992;103:130-9. 13. Elkins RC, Santangelo KL, Randolph JD, et al. Pulmonary

14.

15.

16.

17.

18.

19.

20.

autograft replacement in children: the ideal solution? Ann Surg 1992;216:363-71. Ross DN, Jackson M, Davies J. The pulmonary autograft-A permanent aortic valve. Eur J Cardio Thorac Surg 1992;6: 113-7. O’Brien MF, McGiffin D, Stafford EG, et al. Allograft aortic valve replacement. Analysis of the viable cryopreserved and antibiotic 4°C stored valves. J Cardiac Surg 1991;6(Suppl): 534-43. Kirklin JK, Smith D, Novick W, et al. Long term function of cryopreserved aortic homografts. A lo-year study. J Thoracic Cardiovasc Surg 1993;106:154-66. McGiffin DC, O’Brien MF. A technique for aortic root replacement by an aortic allograft. Ann Thorac Surg 1989;47: 625-7. Daicoff GR, Botero LM, Quintessenza JA. Allograft replacement of the aortic valve versus the miniroot and valve. Ann Thorac Surg 1993;55:855-9. O’Brien MF. Aortic valve implantation techniques. Should thev be any different for the pulmonary autograft and the aortic homograft? J Heart Valve Dis 1993;4:385-7. Clarke DR. Extended aortic root replacement with cryopreserved allografts: do they hold up? Ann Thorac Surg 1991; 52~669-73.

DISCUSSION SIR MAGDI H. YACOUB (Moderator) (London, England): I have a question to you with regard to selection criteria for these patients. What factors influence your decision making? DR RUBAY: The decision-making process is dependent on the geometry of the annulus and the geometry of the ascending aorta. If the diameter of the aortic annulus is similar to the ascending aorta with no dilatation we prefer a subcoronary implantation or intraluminal cylinder. If there is any dilatation of the aortic root or dilatation of the ascending aorta we would prefer root replacement. SIR MAGDI H. YACOUB: ent, would that influence groups over the long-term? DR

RUBAY:

I have

As the selection your comparison

no answer

to that

SIR BRIAN G. BARRATT-BOYES Zealand): In the case of pulmonary

criteria were differbetween the three

DR RUBAY: When we started to use autografts we started using subcoronary implantation and were disappointed to have grade 2 aortic regurgitation in 1 patient, so we now prefer to do intraluminal cylinder or root replacement with autograft, and in the pediatric age group we definitely use root replacement. SIR BRIAN G. BARRATT-BOYES: Would you now consider using the subcoronary technique because you have more experience? Do you think that you can achieve better results as time goes on with the learning curve?

question.

(Moderator) autograft,

replacement in all cases or did you use freehand subcoronary placement? We would like to know more about the factors that influenced your results. Also, do you think now that because you have obtained more experience and technical expertise you may have fewer problems with freehand subcoronary placement?

(Auckland, New did you use root

DR

RUBAY:

Yes,

I do.