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Timing of Surgery for Chronic Aortic Regurgitation
Abstract & Commentary
Synopsis: Waiting for symptom development before recommending valve replacement surgery in young patients with severe aortic regurgitation due to rheumatic disease resulted in an overall 91% survival, free of symptoms over 10 years.
Source: Tarasoutchi F, et al. J Am Coll Cardiol. 2003;41:1316-1324.
In many countries and parts of the United States, the major etiology of aortic regurgitation is rheumatic fever. Such patients are often younger and, accordingly, may not suffer irreversible myocardial damage if surgery is delayed until symptoms appear, rather than operating when certain echocardiographic measurements of left ventricular size and function appear. Thus, investigators at the University of Sao Paulo Medical School in Brazil, tested the hypothesis that waiting for symptoms before valve replacement surgery in chronic severe aortic regurgitation predominantly due to rheumatic fever is feasible and results in good long-term outcomes. They identified 75 asymptomatic patients (mean age, 28 years) with severe aortic regurgitation defined by a cardiothoracic index > 50 on chest x-ray; ECG evidence of left ventricular hypertrophy; a pulse pressure > 80 mm Hg; diastolic blood pressure < 60 mm Hg; and Doppler criteria. The patients were enrolled between 1988 and 1989, and were followed for a minimum of 10 years. Digitalis and diuretics were given to 30%, but none were on vasodilator drugs. Patients were seen regularly and studied by echocardiography and rest-exercise radionuclide angiography. Symptoms developed in 37 patients, who then underwent aortic valve surgery within 6 months, 30 of whom became asymptomatic after surgery. The remaining 38 remained asymptomatic and were managed medically. Thus, at the end of 10 years, 68, or 91%, were asymptomatic. The average time to symptoms was 4.6 years. Survival was 100% in asymptomatic patients and 82% in symptomatic patients. Left ventricular size and performance measurements did not change significantly over time unless the patients underwent surgery. Then there was positive remodeling observed in 92%. Interestingly, no change in left ventricular size or performance measures were observed at the time patients became symptomatic. There were no perioperative deaths, 3 patients died waiting for surgery, and 4 patients died of prosthetic valve complications.
Multivariate analysis showed that baseline age and left ventricular end-systolic dimension (LVESD) were independent predictors of the development of symptoms. In patients with an LVESD > 50 mm at entry, 76% became symptomatic after 10 years (odds ratio 5.6, sensitivity 51%, specificity 84%). Tarasoutchi and associates concluded that waiting for symptom development before recommending valve replacement surgery in young patients with severe aortic regurgitation due to rheumatic disease resulted in an overall 91% survival, free of symptoms over 10 years.
Comment by Michael H. Crawford, MD
In 1980, Henry and colleagues1 reported that certain echocardiographic left ventricular performance measures predicted a poor outcome after valve replacement for chronic severe aortic regurgitation. This led to the concept that if these measurement cut-off points were used as an indication for surgery in asymptomatic patients, poor surgical outcomes would be avoided. Subsequent studies by Fiorelli and associates,2 Daniel and colleagues,3 and others done in the 1980’s, using newer surgical myocardial preservation techniques, refuted this notion and suggested that one could wait for symptoms. In the 1990’s, Bonow and associates4 reported that almost all asymptomatic patients with normal initial echocardiographic values developed symptoms before they developed left ventricular dysfunction. Thus, the ACC/AHA guidelines of 1998 list symptom development as a class I indication and achieving certain echo parameters of left ventricular size and function as class IIa.5 This means that physicians confronting asymptomatic patients with abnormal echo indices should individualize their recommendations based upon characteristics of the specific patient. This study supports the concept that in younger patients with rheumatic aortic valve disease, waiting for symptoms to occur was associated with a favorable outcome and is a reasonable course of action. This is welcome news to clinicians who often find it difficult to convince an asymptomatic patient to undergo major surgery with significant long-term consequences.
This study was started over a decade ago, before long-term vasodilator therapy was shown to be of some benefit in such patients. Perhaps their patients would have even done better if on these agents. On the other hand, vasodilator therapy results have been reported in < 400 patients in the literature, and not all studies have shown clearcut benefits. Also, the best agent (nifedipine, hydralazine or ACEI) is unclear, as is the best dosage of administration. The excellent results in this study raise further doubt about the efficacy of vasodilator therapy for chronic aortic regurgitation.
Another interesting point is that the use of rest-exercise radionuclear angiography to assess the left ventricular function response to exercise was of no value in this study. This approach to the evaluation of left ventricular reserve in valve disease patients was popularized by Borer and associates in 1978.6 A subsequent study by Bonow and colleagues in 19837 showed that the rest-exercise response was not independent of the resting ejection fraction, which was the best predictor of outcome. Despite this study, the approach has died slowly and was still in use when this study started in 1988. The accompanying editorial by Gaasch and Schick8 points out that all but 2 patients in the Brazilian study had normal ejection fractions. Thus, they believe these data are not applicable to patients with ejection fractions < 50%, who they believe should have surgery even if they are asymptomatic. However, they agree that it may be prudent to wait for symptoms if only left ventricular dilatation is present.
Dr. Crawford if Professor of Medicine, Mayo Medical School; Consultant in Cardiovascular Diseases, and Director of Research, Mayo Clinic, Scottsdale, AZ.
1. Henry WL, et al. Circulation. 1980;61:471-483.
2. Fiorelli P, et al. Circulation. 1983;67:216-221.
3. Daniel WG, et al. Circulation. 1985;71:669-680.
4. Bonow RO, et al. Circulation. 1991;84:1625-1635.
5. Bonow RO, et al. Circulation. 1998;98:1949-1984.
6. Borer JS, et al. Am J Cardiol. 1978;42:351-357.
7. Bonow RO, et al. Circulation. 1983;68:509-517.
8. Gaasch WH, Schick EC. J Am Coll Cardiol. 2003;41:1325-1328.