Bentall Operation with Valved Homograft Conduit

Abstract

Lesions of the ascending aorta associated with aortic valve disease are usually treated by implanting a prosthetic valved conduit (Bentall procedure). In this report, we present our experience in which a valved homograft conduit was used for the procedure.

Six patients underwent a Bentall procedure with the use of a cryopreserved valved homograft conduit. Two of the patients had annuloaortic ectasia, 2 had Marfan syndrome, and 1 had an atherosclerotic aneurysm of the aorta. One patient had severe aortic stenosis due to a bicuspid aortic valve, along with an aneurysm and localized dissection of the ascending aorta. In all of the patients, the aortic annulus was substantially dilated, with accompanying moderate-to-severe aortic regurgitation. A standard procedure was performed with moderate hypothermia, cardiopulmonary bypass, and aortic and bicaval cannulation. The ascending aorta and the aortic valve were replaced with a cryopreserved valved homograft conduit (aortic in 5 patients and pulmonary in 1). The native coronary ostia were anastomosed directly to the homograft.

Echocardiography, which was performed intraoperatively, before discharge from the hospital, and at follow-up visits (1 to 36 months), revealed good valve function without dilatation of the homograft conduits. There was 1 late death due to Aspergillus fumigatus endocarditis, 6 months postoperatively. In 1 patient, magnetic resonance imaging performed at 24 months revealed normal caliber of the homograft conduit.

We conclude that the Bentall procedure can be performed, safely and with excellent results, using cryopreserved homograft conduits.

Lesions of the ascending aorta with associated aortic valve disease are usually treated by implanting a prosthetic valved conduit (Bentall procedure). ¹ This conduit, however, has the attendant hazards of anticoagulation and an increased risk of infective endocarditis. Few authors ^2–4 have reported the use of a homograft conduit for the Bentall procedure, and others have expressed doubts about its suitability. ^5,6 We present herein our experience using a valved homograft conduit for the Bentall procedure in 6 patients.

Patients and Methods

At our center, 6 male patients (aged 11 to 65 years) underwent Bentall procedures with cryopreserved valved homograft conduits from June 1996 through July 1999. The patient profiles are presented in Table I. Two of the patients had annuloaortic ectasia, 2 had Marfan syndrome, and 1 had an atherosclerotic aneurysm of the aorta. Another patient had severe aortic stenosis due to a bicuspid aortic valve, along with an aneurysm and localized dissection of the ascending aorta. In all 6 patients, the aortic annulus was substantially dilated, with accompanying moderate-to-severe aortic regurgitation (Fig. 1). Cardiac catheterization, transthoracic echocardiography, and intraoperative transesophageal echocardiography were performed in all patients.

TABLE I. Profile of 6 Male Patients Undergoing the Bentall Operation with a Cryopreserved Homograft

Fig. 1 Aortic root angiogram of Patient 1 in left anterior oblique view. The ascending aorta (AA) and the aortic root are dilated, with severe aortic regurgitation (annuloaortic ectasia).

LV = left ventricle

A standard operation was performed, with the patient under moderate hypothermia, cardiopulmonary bypass, and aortic and bicaval cannulation. After the aortic cross-clamp was applied, the ascending aorta was opened longitudinally, and hyperkalemic, blood cryocardioplegic solution was infused directly into the coronary ostia. The aortic cusps were either partially excised or not excised at all. An appropriately sized homograft conduit (aortic in 5 patients and pulmonary in 1) was selected and thawed. The proximal end of the graft was sutured to the native aortic annulus with interrupted 4-0 polypropylene sutures. The native valve cusps were used to buttress the suture line. After the row of interrupted sutures was completed, another continuous suture was passed between the native aortic annulus and the adventitia of the homograft in order to ensure hemostasis. The aortic homografts were placed in their natural position without rotation. Anastomosis was performed from the native left and right coronary artery ostia to the corresponding coronary ostia of the aortic homograft, or to the newly created openings in the case of the pulmonary homograft. Distally, the homograft was sutured to the aorta, proximal to the origin of the innominate artery. The native aortic wall was wrapped around the homograft. A Cabrol fistula ⁷ was made in all patients, between the right atrium and the native aortic wall.

At the completion of the procedure, intraoperative transesophageal echocardiography was performed to evaluate homograft function. Echocardiography was also performed before the patients' discharge from the hospital and at follow-up visits.

Results

All patients survived the operation. The early postoperative period was uneventful, and all 6 patients were discharged from the hospital after a stay of 7 to 9 days. Pre-discharge echocardiography showed good valve function. Transesophageal echocardiography, performed after 1 to 36 months, showed no aortic regurgitation and no dilatation of the homograft. The Cabrol fistula was observed to have closed in all patients after an interval varying from 5 days to 1 month. In Patient 1 (Table I) magnetic resonance imaging at 24 months revealed normal caliber of the homograft conduit (Fig. 2).

Fig. 2 Postoperative magnetic resonance image (spin-echo image in the coronal plane) of Patient 1, showing the homograft in the aortic root. The homograft is normal in diameter without evidence of dilatation.

Patient 5 (see Table I), who received a pulmonary homograft conduit at the initial operation, developed fungal endocarditis (Aspergillus fumigatus) after 6 months and underwent reoperation. After extensive débridement, the old homograft conduit was replaced with a cryopreserved aortic homograft conduit. Postoperatively, the patient developed overwhelming fungal septicemia and died 15 days later.

Discussion

Excellent long-term results have been reported in terms of survival, freedom from reoperation, and other valve-related events with aortic valve replacement using a cryopreserved homograft. ⁸ However, the use of a valved homograft conduit to replace the aortic valve and the ascending aorta remains controversial, especially in patients with Marfan syndrome, annuloaortic ectasia, and ascending aortic aneurysm with aortic regurgitation. There has been concern regarding postoperative valve failure due to progressive dilatation of the native annulus. ^5,6 Although experimental studies ^9,10 have shown significant dilatation of the pulmonary homograft conduit when it is inserted into the systemic circulation, clinical reports have shown no such dilatation with the use of aortic homografts. ^2–4 Indeed, in our patients, we observed no deterioration of valve function up to our maximum follow-up of 36 months. Late function of the pulmonary homograft conduit could not be evaluated because of the patient's death 6 months postoperatively.

In our opinion, the Bentall procedure with a valved homograft conduit, similar to aortic valve replacement with a homograft, is a safe procedure and should yield excellent long-term results. There is no threat of annular dilatation and progressive aortic regurgitation unless the native aortic root is grossly dilated preoperatively. Our technique of using the native cusps to reinforce the proximal suture line is likely to reduce this threat even further.

The major advantages of this technique are the ease of suturing and the lack of bleeding problems. Moreover, there is no kinking of the coronary arteries when the homograft is oriented in the anatomic position. Postoperative benefits include normal hemodynamic function and no anticoagulation requirement.