Ann Thorac Surg 2007;84:356-357
© 2007 The Society of Thoracic Surgeons
Correspondence
Reply
Ramdas G. Pai, MD,
Padmini Varadarajan, MD
Division of Cardiology, Loma Linda University Medical Center, #4414, Loma Linda, CA 92354
(Email: ramdaspai{at}yahoo.com).
To the Editor:
We appreciate the thoughtful comments of Dr Cannata and colleagues [1] regarding our article [2]. We agree that our findings have important medical and legal implications, but more importantly, they have important clinical and ethical obligations in view of a large potential survival benefit of aortic valve replacement (AVR) in asymptomatic patients with severe aortic stenosis (AS). Because of the retrospective nature of this study, it was not possible to be certain if patients had complained of any cardiac symptoms that developed during the follow-up. However we would like to make the following important practical points:
- (1) There are no randomized trials evaluating the effect of AVR in severe AS patients, and the current guidelines and practices are based on interpretation of observational studies [3–5].
- (2) "Asymptomatic status" is an unreliable piece of history to hinge the decision of AVR. Many of the severe AS patients are elderly with limited mobility. Also because of gradual symptom onset, patients learn to live within symptoms. Das and colleagues [6] have shown that about half of the patients who claim to be asymptomatic are truly symptomatic when they are subjected to a stress test. In our own series of "asymptomatic" patients, 10% had a pulmonary artery systolic pressure > 60 mm Hg, and 12% had left ventricular ejection fraction < 0.30 [7]. It is hard to imagine that these patients were truly asymptomatic. It is clear that the presence of severe AS is the most powerful predictor of mortality when left uncorrected.
- (3) Prohibitively high event rates we observed in the patients who did not undergo an operation are not inconsistent with the observations of three of the previously reported natural history studies, although they addressed slightly different populations [4, 5, 8]. The small subset of severe AS patients (judged by transaortic velocity of > 4 m/s) reported by Otto and colleagues [4] had a 2-year event rate of 79%. The series by Rosenhek and colleagues [5] addressed younger patients, but older patients and those with severe aortic valve calcification had event rates approaching 50% at 2 years. Series by Pellikka and colleagues [8] had patients with less severe AS (mean valve area 0.9 cm2 compared with 0.72 cm2 in our series), but had a 2-year event rate of 37% [8]. Interestingly 145 of 325 patients who remained asymptomatic had AVRs with a large survival benefit [8].
- (4) Given these data, we agree that the current guidelines [9] have to be re-examined and perhaps the class III indication for AVR in asymptomatic severe AS has to be softened, given the inaccuracy of symptoms, high event rates in these individuals, and potential benefit of AVR. Only a randomized study can answer these questions for certain, and until then a class II indication for AVR in "asymptomatic" severe AS does not seem unreasonable.
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References
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- Cannata A, Fratto P, Vitali E. Asymptomatic aortic valve stenosis: to operate or not to operate?(letter) Ann Thorac Surg 2007;84:355-356.[Free Full Text]
- Pai RG, Kapoor N, Bansal RC, Varadarajan P. Malignant natural history of asymptomatic severe aortic stenosis: benefit of aortic valve replacement Ann Thorac Surg 2006;82:2116-2122.[Abstract/Free Full Text]
- Ross J, Braumwald E. Aortic stenosis Circulation 1968;38(Suppl 5):V61-V67.
- Otto CM, Burwash IG, Legget ME, et al. Prospective study of asymptomatic valvular aortic stenosis: clinical, echocardiographic and exercise predictors of outcome Circulation 1997;95:2262-2270.[Abstract/Free Full Text]
- Rosenhek R, Binder T, Porenta G, et al. Predictors of outcome in severe asymptomatic aortic stenosis N Engl J Med 2000;343:611-617.[Abstract/Free Full Text]
- Das P, Rimington H, Chambers J. Exercise testing to stratify risk in aortic stenosis Eur Heart J 2005;26:1309-1313.[Abstract/Free Full Text]
- Pai RG, Varadarajan P, Kapoor N, Bansal RC. Malignant natural history of asymptomatic severe aortic stenosis: benefit of aortic valve replacement Ann Thorac Surg 2006;82:2116-2122.[Abstract/Free Full Text]
- Pellikka PA, Sarano ME, Nishimura RA, et al. Outcome of 622 adults with asymptomatic, hemodynamically significant aortic stenosis during prolonged follow-up Circulation 2005;111:3290-3295.[Abstract/Free Full Text]
- Bonow RO, Carabello BA, Kanu C, et al. American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; Society of Thoracic Surgeons ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons Circulation 2006;114:e84-e231.[Free Full Text]
Related Article
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Asymptomatic Aortic Valve Stenosis: To Operate or Not to Operate?
- Aldo Cannata, Pasquale Fratto, and Ettore Vitali
Ann. Thorac. Surg. 2007 84: 355-356.
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