Aortic valve preservation surgery in elderly patients with aortic stenosis

Objective: The aim of the present study was to investigate early and late results of the aortic valve preservation surgery (AVPS) through rough-hewing, demineralization and commissurotomy of the aortic valve (AV) in aortic stenosis (AS) at elderly people. Methods: Thirty-two patients operated for pure AS, older than 65 years-old were studied at InCor FMUSP. Early and late results, clinical (ambulatory and phone interview) and echocardiographic follow-up were investigated. Actuarial and event-free survival analysis was done using the KaplanMeier method. Results: Four patients (15.4%) had presented de novo AV stenosis. Five patients had progressed to moderate and two to serious aortic regurgitation. Demineralization, commissurotomy and rough-hewing were realized in 28, 20 and 16 patients, respectively. Nine patients had presented serious postoperative complications (28.1%). Two hospitalacquired pneumonia sepsis and five late deaths had occurred. Postoperative NYHA functional status were 70.5%, 17.6%, 5.8% and 5.8% for functional classes I, II, III and IV, da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brasil. Endereço para correspondência: Rodrigo Coelho Segalote. Rua dois de dezembro, 66, apto 1004. – Flamengo Rio de Janeiro, RJ – Brasil CEP 22220-040. E-mail: segalote@yahoo.com.br Artigo recebido em 4 de julho de 2008 Artigo aprovado em 3 de novembro de 2008


INTRODUCTION
Aortic stenosis (AS) is a disease that is relatively prevalent in the elderly (2.9%) [1].According to the IBGE 1991/2000, the frequency has been increasing year after year.The number of people over 75 years old has reached 1.6% in a country with more than 146 million inhabitants [2].Thus, the interest in this pathology in this age group has also increased.
There is currently a strong tendency of surgeons to try their best to preserve the valve apparatus, because there is still no ideal valve replacement.In Brazil, Neves et al. and, more recently, Mendonça et al., published their experiences with reconstructive surgery of the aortic valve, particularly for aortic insufficiency, with good results in both studies [3][4].
Although durable, mechanical prostheses have problems with anticoagulation, such as thromboembolism, bleeding, and infection [5].Along with the mechanical prostheses, the bioprostheses also have limitations, largely because of their deterioration after the seventh year after the implant [6].
Among the procedures for the preservation of the aortic valve (AV), percutaneous aortic valvuloplasty is the least invasive, but it failed to reproduce the results of actual valve replacement [7].
Finally, there is AV preservation surgery using cardiopulmonary bypass, which can be performed using ultrasonic decalcification, though this method is not recommended because of its limiting side effects, including postoperative aortic insufficiency and early restenosis [8][9].Another method of performing this preservation surgery is manual valve repair using decalcification, reshaping and AV commissurotomy.This method is the focus of this study.
This procedure has been recommended for the elderly, for patients with a small aortic annulus and/or contraindication to anticoagulation; due to the higher surgical risk for the former group, and increased mortality in surgery for aortic annulus enlargement in the latter group [10][11][12][13].
The aim of this study is to present immediate and longterm results of AV preservation surgery using reshaping and decalcification, as well as the results of AV commissurotomy in the elderly.

METHODS
From November 1987 to November 2007 in the Heart Institute of the Faculty of Medicine at the University of São Paulo, 526 patients with isolated AS underwent surgery.Thirty-two patients (6%) underwent AV repair.All patients were over 65 years old, and the decision to go through with AV repair was decided by the surgeon.
The patients were selected from electronic medical records and then retrospectively analyzed by a systematic review of medical records.We analyzed the immediate and long-term results, the echocardiographic follow-up performed by the cardiologist, and the clinical follow-up.The clinical follow-ups were performed through outpatient consultations and phone interviews.
The morbidity and mortality related to valve surgery were defined according to the Guidelines for Reporting Morbidity and Mortality After Cardiac Valvular Operations [14].Survival curves were calculated using the Kaplan-Meier method.The linear rates of the events are expressed by percentage per patient/year.The study was approved by the Scientific Committee of the Heart Institute and by the Ethics Committee of the Clinics Hospital of the College of Medicine at the University of São Paulo.
The patients with coronary artery disease (in which coronary artery bypass grafting were needed) were excluded from the study in order to not affect results, because there are studies that show an increased mortality associated with coronary artery bypass grafting and AV preservation [5,[15][16].

RESULTS
The mean age was 73.3 +/-4.7 years.The majority of the patients were women, with 23 female patients (71.8%).The demographic data and the preoperative characteristics are shown in Table 1.
In the preoperative echocardiogram, we noted that the average peak gradient of left ventricle/aorta (PG LV/Ao) was 76 +/-28.3mmHg, and that the mean left ventricular ejection fraction (LVEF) was 0.64 +/-0.1, with eight patients with left ventricular dysfunction.The preoperative functional class according to the New York Heart Association (NYHA) in descending order was 53.1%, 21.8%, 15.6% and 0%, for the III, II, IV and I functional classes, respectively (Figure 1).Four patients (15.4%) presented AV restenosis, with the postoperative echocardiogram showing a mean of PG LV/ Ao 90.2 +/-24.7 mmHg.Among the patients who presented no restenosis, the mean PG LV/Ao was 31.7 +/-9.6 mmHg.The mean postoperative LVEF was 0.59 +/-0.1, with six patients with left ventricular dysfunction.Five patients developed mild aortic insufficiency and two developed severe aortic insufficiency; from these two patients, the first was reoperated at eight months and the second at 26 months, with a bioprostheses implant.Echocardiographic follow-up was performed in 27 patients (84.7%) with a mean of 15.9 +/-20.4months.
There were two (6.2%) hospital deaths due to sepsis caused by hospital-acquired pneumonia and five (15.6%) deaths from late-onset pneumonia.Two (6.2%) patients died from infections and three (9.3%)from complications related to the valve.

DISCUSSION
Decalcification surgery, reshaping, and AV commissurotomy are rarely used by most surgeons, because the results of aortic valve replacement are well established.But when comparing our results with the results of valve replacement, we note similarities.Hospital mortality in some studies ranged from 3.8% to 15% [5,[12][13][15][16][17][18][19]21,22].The mean of these results was no different from what we found in our study, which was a mortality rate of 6.2%.However, regarding late mortality related to the valve, Tseng et al. showed 21.6%, whereas we obtained 9.3%.
The survival curve in eight years of this study showed better results than that presented by Bottio et al. in their study with Biocor biological prostheses in a general population: 66.9 +/-12.1% versus 48 +/-5%.Our results were similar to De Bacco et al.'s study, which showed a survival of 66.5 +/-8.6.However, the study performed by Aksoyek et al. with mechanical prostheses in the elderly showed better results: 66.9 +/-12.1% versus 84.7 +/-6% [5,[20][21].
In a study with a 12-year follow-up analysis, Braile et al. presented excellent results with the BIOPRO bovine pericardium bioprostheses, regarding both overall survival rate (91.7 +/-2.2%) and survival rate in patients over 70 years (58.1 +/-17.2%)[22].Studies on aortic valve repair with a larger follow-up should be performed so we can compare the long-term actuarial survival.
Regarding the curve without thromboembolism and endocarditis in eight years, we found similar results to these authors' studies [5,[20][21].Analyzing the postoperative PG LV/Ao, we found no differences when compared to the results of Bottio et al. [20].The postoperative quality of life can also be compared in studies of Sundt et al.Kolh and et al., in which over 80% of patients presented in NYHA I and II functional class [15,23].
Shapira et al. retrospectively studied AV repair due to AS in adults and divided the patients into three groups: patients with congenital AS, rheumatic patients, and elderly patients, and found similar results -but with a higher rate of restenosis (24%) and an actuarial curve free of symptoms at 87% [24].In another study, Weinschelbaum et al. prospectively analyzed the elderly and noted similar results, but with a high occurrence of restenosis and reoperation, because most patients recommended for this procedure are the elderly, those with a small aortic annulus, and those with contraindication to anticoagulation [10].

CONCLUSION
AV preservation surgery in elderly patients with AS in this series of patients has been shown to be safe, with low morbidity and mortality rates, a satisfactory survival rate at eight years, and an improvement in functional class in the follow-ups of the presented patients.

ACKNOWLEDGMENTS
My sincere thanks to Ph.D Professor Pablo Pomerantzeff and Carlos Manuel Brandão, PhD, for supporting this study with the Surgical Unit of Valve Diseases -InCor, FMUSP.

Table 1 .
Demographic and preoperative data Variable SAH= Systemic Arterial Hypertension; ARF= Acute Renal Failure COPD= Chronic obstructive pulmonary disease; PVF= Peripheral vascular failure; Stroke