Asian Cardiovasc Thorac Ann 2006;14:289-293
© 2006 Asia Publishing EXchange Ltd
Mid-Term Results of Ross Procedure: Our Limited Experience
Rong Wang, MD,
Alan Farnsworth, FRCS,
Helmi Albrecht, BChemEng
Department of Cardiothoracic Surgery, St. Vincents Hospital, Sydney, Australia
For reprint information contact: Alan Farnsworth, FRCS Tel: 61 2 8382 6868 Fax: 61 2 8382 6869 Email: aefarnsworth{at}stvincents.com.au, Suite 811, St. Vincents Clinic, St. Vincents Hospital, Sydney, 438 Victoria Street, Darlinghurst, New South Wales 2010, Australia.
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ABSTRACT
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From February 1995 to February 2005, 30 patients underwent the Ross procedure with the root replacement technique. There were 20 males (66.7%) and 10 females (33.3%), aged 13 to 49 years. The diagnosis was aortic stenosis in 12 patients (40%), aortic regurgitation in 10 (33%), mixed stenosis and regurgitation in 6 (20%), prosthetic endocarditis with an aortic root abscess in 1 (3.3%), and a perivalvular leak in 1 (3.3%). There was no early or late death. Six patients (20%) suffered 7 significant operative complications. Over a median follow-up of 65 months (range, 4–114 months), there were 3 re-operations for autograft failure and 2 for homograft failure. No patient experienced a cerebrovascular accident, and all but one were free from endocarditis. Freedom from autograft failure was 94.1% ± 5.7% at 5 years and 79.5% ± 10.7% at 8 years, while freedom from homograft failure was 96.6% ± 3.4% at 5 years and 88.5% ± 8.3% at 8 years. Our midterm results show that good early and late survival can be obtained in young patients with aortic valve disease. Re-exploration for bleeding and late autograft failure are the main concerns of this challenging operation, especially early in the surgeon’s learning-curve.
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INTRODUCTION
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Replacement of aortic and mitral valves with a pulmonary autograft was pioneered by Donald Ross1 in 1967, but the procedure was not widely applied because of the technical challenge and uncertainty about its short- and long-term results until the 1990s when additional experience was reported by a few other cardiac surgeons. Theoretically, this operation offers many advantages including: long-term durability, absence of anticoagulation, potential growth ability, and excellent hemodynamic performance.2 Recently, several reports of mid- and long-term results of the Ross procedure have confirmed that this operation is promising for a selected patient population.3–6 The purpose of this study was to review our limited experience of the Ross procedure.
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PATIENTS AND METHODS
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From February 1995 to February 2005, 30 patients underwent aortic valve and root replacement with a pulmonary autograft under a single responsible surgeon (AF) in St. Vincents Hospital, Sydney. The Ross procedure was offered to patients under 50 years old on their cardiologist’s referral or their surgeon’s suggestion, after careful evaluation of their status. There were 20 males (66.7%) and 10 females (33.3%). Age ranged from 13 to 49 years, with a median age of 23 years. Sixteen patients were in New York Heart Association class I and 14 were in class II. The predominant preoperative diagnoses are listed in Table 1
. Of the 30 patients, 16 (53.3%) were found to have a bicuspid aortic valve, 2 (6.7%) had a history of endocarditis, and 1 (3.3%) had a history of rheumatic fever. One patient had a severely calcified aortic valve complicated with a calcified embolus to his left eye preoperatively, and 7 had previously undergone 12 interventions (Table 2). Transthoracic echocardiography was carried out in all patients preoperatively to measure the diameter of the aortic and pulmonary annuli and to assess heart function and the competency of the pulmonary valve. Patients with a pulmonary valve deformity or even trivial pulmonary regurgitation were excluded. In all patients, the diameter of the aortic annulus did not exceed that of the pulmonary annulus by more than 3 to 4 mm.
Intraoperative transesophageal echocardiography was performed to confirm the preoperative evaluation. All autografts were implanted by the root replacement technique, as described by others.3 Briefly, using a standard technique of cardiopulmonary bypass and retrograde perfusion of cold blood cardioplegia, the aorta was crossclamped and transected just above the sinotubular junction. The aortic valve was excised and the pulmonary artery was opened below the bifurcation. After confirming that the anatomy was suitable for a Ross procedure, the pulmonary trunk was isolated and removed with a 5 mm muscle cuff on the proximal end. The muscle cuff was attached to the aortic annulus using continuous 4/0 polypropylene sutures, and the coronary buttons were re-implanted with continuous 5/0 polypropylene sutures. Aortic continuity was restored and the right ventricular outflow tract was reconstructed with insertion of a cryopreserved pulmonary homograft conduit. Neither suture line of the pulmonary autograft was reinforced.
Patients and/or their cardiologists were contacted for clinical outcomes every two years. Transthoracic echocardiography was carried out before discharge in our clinic and thereafter every 2 years by the referring cardiologist. The follow-up rate was 96.7%; one patient was lost to follow-up. No anticoagulants were administered to any patient after the operation.
Kaplan-Meier analysis was used to determine freedom from re-operation caused by autograft or homograft failure. Data were analyzed with SPSS version 12.0 software (SPSS Inc., Chicago, IL, USA).
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RESULTS
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There was no operative or early death in this patient group. The crossclamp time ranged from 80 to 161 min, with a median of 105 min. One patient who needed a long crossclamp time (161 min) underwent concomitant repair of a fistula between the aorta and right atrium during his Ross procedure. Before that, he had undergone aortic valvotomy, aortic valve replacement with a homograft, and aortic valve replacement with a mechanical valve for his primary aortic stenosis; he was also complicated by prosthetic endocarditis and an aortic root abscess. The technical difficulty and concomitant procedure necessitated a long crossclamp time in this case. The median length of stay in the intensive care unit was 1 day (1–8 days). The median time to discharge was 7 days (4–17 days). There were 7 significant complications in 6 patients (20%; Table 3). All patients recovered well and were discharged uneventfully. Transthoracic echocardiography demonstrated that two patients had mild autograft regurgitation and the others had trivial or no regurgitation before discharge.
Over a median follow-up of 65 months (range, 4–114 months), there was no late death. Four patients (13.8%) underwent re-operation for autograft and/or homograft failure (Table 4). Of 29 patients with complete follow-up data, none experienced a cerebrovascular accident, and all but one were free from endocarditis. Freedom from autograft failure was 94.1% ± 5.7% at 5 years and 79.5% ± 10.7% at 8 years, while freedom from homograft failure was 96.6% ± 3.4% at 5 years and 88.5% ± 8.3% at 8 years (Figures 1 and 2). All patients were in New York Heart Association class I at their last follow-up. Late transthoracic echocardiography results were available in 20 patients and demonstrated greater than mild autograft regurgitation in one patient and mild homograft stenosis in another after a median follow-up period of 45.5 months (range, 4–88 months). Postoperative echocardiographic assessments of the pulmonary autografts and homografts are shown in Tables 5 and 6.
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DISCUSSION
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This was a small patient cohort consisting of adolescents and young adults. It reflects on the one hand, the reality of a small population in Australia and an adult cardiac center, and on the other hand, our strict selection policy. We are prudent and conservative in offering this difficult operation to a patient unless he/she is a really appropriate candidate. Like others, we choose candidates for the Ross procedure after a comprehensive evaluation including age, life expectancy, contraindication to anticoagulation, pathology of the aortic valve, left ventricular function, and the patient’s wishes.7 Among these factors, age, life expectancy, and aortic valve pathology are the most important. The benefits of a pulmonary autograft for pediatric patients have been well documented, especially its potential growth ability and long-term durability.8,9,10 This encouraged many surgeons to extend this operation to young adults and even middle-aged patients (45–65 years old) with a life expectancy of 20 years or more. Elkins suggested that the Ross operation might be suitable for all patients with aortic valve disease and a life expectancy of more than 20 years.11 We set 50 years as the upper limit of age in this series, and most (93.3%) of the patients were under 40 years old. The benefits provided by the Ross procedure for patients aged 40 to 50 years are not as distinct as those for the pediatric group. A retrospective study comparing pulmonary autografts with xenografts (stented and stentless) and homografts for patients in the middle-aged group (45–65 years) found that midterm survival or valve-related morbidity were comparable among these valve substitutes, but the pulmonary autograft gave the best hemodynamic performance.12 However, the durability of xenografts has been reported to be inversely related to age at implantation.13 Thus, it is our view that patients aged between 40 and 50 years can more reasonably expect to obtain the benefits of improved left ventricular function and longer durability from a pulmonary autograft than from a stented or stentless xenograft.
In terms of pathology, congenital bicuspid aortic valve disease was the main indication for surgery in this cohort, which was consistent with the prevalence of this abnormality in adolescents and young adults. We prefer to perform this operation for patients with aortic stenosis rather than insufficiency, despite the fact that almost half of the patients in this series had isolated aortic insufficiency or mixed stenosis and insufficiency. It is more common to see aortic root dilatation and a geometric mismatch between the aorta and the pulmonary artery in patients with aortic insufficiency than those with stenosis. Moreover, several previous studies have demonstrated that preoperative aortic insufficiency is related to a higher rate of re-operation secondary to central autograft incompetence.14,15 Bearing this in mind, we take careful steps in approving patients with aortic insufficiency for this operation. Only those with neither root dilatation nor a mismatch between the aortic and pulmonary annulus of more than 3–4 mm were included in this series.
The success of the Ross procedure depends not only on strict selection of the best candidates but also on a good operative technique. A few mid-term and long-term results have demonstrated the reliability, reproducibility, and safety of the free-standing aortic root technique since it was introduced by Stelzer and colleagues16 in 1989.3,5,10 In this series, all patients underwent the root replacement technique and there was no operative mortality or late death, even though an extremely complicated case was included. Our early and late mortality results are better than those reported in the International Registry of the Ross Procedure after 1987: 2.5% and 1.7%, respectively.17 However, compared with the encouraging survival results, postoperative morbidity was high (20%) and the re-operation rate for autograft failure is frustrating (10.3%). The morbidity was mainly due to re-exploration for bleeding, which was surgical in only one case and due to coagulopathy in the other 3, indicating the importance of antifibrinolytic agents and meticulous hemostasis during the operation.
Pulmonary autograft failure is regarded as the primary cause of re-operation after the Ross procedure. Elkins and colleagues2 categorized autograft failure into early and late dysfunction. Early failure (within 1 year) can be attributed to technical errors and the surgeon’s learning curve, such as autograft misalignment after insertion and injury to the leaflets during implantation. The advent of the root replacement technique and accumulation of surgical experience have dramatically eliminated these errors, and good early results have become achievable. Late failure (beyond 1 year) is probably caused by both patient-related and operative factors. These factors may include a preoperative diagnosis of aortic insufficiency, a dilated aortic annulus, a genetic connective tissue disorder of the aortic wall, and progressive dilatation of the pulmonary autograft with the root replacement technique. Some modifications of the root replacement technique have been devised to prevent late autograft failure, with good clinical results. Kouchoukos and colleagues6 found no aortic annular dilatation in their long-term follow-up of patients in whom the suture line between the pulmonary autograft and the aortic annulus was reinforced with a felt strip. Elkins5 reviewed 12 years of experience and proposed annular reduction and fixation as a modification of the root replacement technique, especially for patients with dilated aortic annulus. We did not use any reinforcement because we consider it time-consuming and specifically designed for cases of significant aortic-pulmonary annulus mismatch. Our selection policy excluded any patient with a geometric mismatch > 4 mm. Therefore, we believe that the standard root replacement technique was adequate for our patients. In this series, there was no early autograft failure, demonstrating the benefit of the root replacement technique. In the 3 patients with late failure, degenerative failure and a technical misjudgment were the causes of autograft dysfunction in 2, but the reason for failure in the 3rd patient is unclear. The high re-operation rate for autograft failure seems to be partly associated with the surgeon’s learning curve because 2 occurred in the first 2 patients, one of which was an extremely difficult case from a surgical viewpoint. In the next 27 patients, only one had a re-operation for autograft failure.
Pulmonary homograft failure is another potential risk for re-operation associated with the Ross procedure, although it is rare compared to autograft failure. Homograft degeneration and host immune reaction are possible reasons for dysfunction. Homograft insufficiency can be very well tolerated for many years as long as the pulmonary artery pressures are low. Most homograft stenoses result from degeneration, develop gradually, and can be palliated with balloon catheters. If homograft dysfunction eventually becomes critical enough to require a replacement, re-operation is a relatively uncomplicated procedure that can be accomplished with low mortality. We have acquired experience in this area by treating patients with restenosis of the right ventricular outflow tract after repair of tetralogy of Fallot, with good results; such experience ensured that 2 patients with homograft failure underwent re-operation uneventfully.
Stelzer and colleagues3 found preoperative active endocarditis, rather than a history of endocarditis, was a strong risk factor of poor outcome after the Ross procedure, including high rates of mortality and recurrent endocarditis. They preferred a homograft for patients with active endocarditis. One of our patients with a history of endocarditis was found to have vegetation in his pulmonary homograft postoperatively because of wound infection; this pulmonary homograft was replaced. Another patient with prosthetic endocarditis and aortic root abscess and one with a history of endocarditis underwent the Ross procedure uneventfully. We also prefer aortic homografts to treat patients with active endocarditis. However, as the patient with prosthetic endocarditis and aortic root abscess had undergone a homograft and mechanical valve replacement previously, it seemed that the Ross procedure was the only promising option.
Our midterm results of the Ross procedure agree with those reported by other groups, showing that this operation can be performed with good early and late survival for young patients with aortic valve disease and a life expectancy of more than 20 years. However, re-exploration for bleeding and late autograft failure associated with technical problems and patient-related factors are still the main concerns of this challenging operation, especially early in a surgeon’s learning-curve. Comprehensive efforts should be made to prevent these problems and improve the early and late results.
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ACKNOWLEDGMENTS
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We are grateful to Tom Hunter, Manger of the Database, Department of Cardiothoracic Surgery, St. Vincents Hospital, Sydney, and Kuet S Li, MBA, Heart Valve Bank, St. Vincents Hospital, Sydney.
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REFERENCES
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- Stelzer P, Weinrauch S, Tranbaugh RF. Ten years of experience with the modified Ross procedure. J Thorac Cardiovasc Surg 1998;115:1091–100.[Abstract/Free Full Text]
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- Hampton CR, Chong AJ, Verrier ED. Stentless aortic valve replacement: homograft/autograft. In: Cohn LH, Edmunds LH Jr, editors. Cardiac surgery in the adult. New York: McGraw-Hill, 2003:867–88.
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ABSTRACT
INTRODUCTION
