CORRESPONDENCE: RESEARCH CORRESPONDENCE
Unoperated Patients With Severe Aortic Stenosis
David S. Bach, MD, FACC*,
Nina Cimino and
G. Michael Deeb, MD, FACC
* CVC Room 2147, SPC 5853, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (Email: dbach{at}umich.edu).
To the Editor: Aortic valve replacement (AVR) is an accepted standard for the treatment of aortic stenosis (AS) (1,2). Patients with symptoms exhibit superior survival after AVR, making symptomatic severe AS a well-accepted indication for AVR. In asymptomatic patients, stress testing is now accepted to help estimate risk and guide AVR (2). Advanced age and comorbidities that increase operative risk may result in failure to intervene (3–5). One large, multicenter European survey suggested that only 47% of patients with AS underwent AVR, and that 32% of patients with severe single-valve disease and class III or IV symptoms did not undergo intervention (6). Reasons included patient age and perception of surgical risk. No data are available for similar patients in the U.S. This survey examines the reasons why adult patients in the U.S. with severe AS did not undergo AVR.
The University of Michigan echocardiography database was reviewed to identify adult patients with evidence of severe AS documented during calendar year 2005. Severe AS was defined as a mean gradient  40 mm Hg, calculated valve area <1.0 cm2, or overall echocardiographic assessment of severe AS. Medical records were reviewed to determine whether there were symptoms referable to AS. If AVR was not performed, records were reviewed to determine why. For patients who did not undergo AVR, anticipated operative risk of AVR was calculated using the logistic EuroScore (7) using clinical data at the time of echocardiography. The study protocol was approved by the institutional review board.
During 2005, 159 patients had an echocardiogram interpreted to show severe AS. Four patients were excluded, 1 because of insufficient medical information and 3 because AS was felt not to be severe based on other data. Of the remaining 155 patients, 80 (52%) underwent AVR and 75 (48%) did not. The 75 unoperated patients included 31 women and 44 men; mean age 68.1 ± 15.0 years (range 34 to 91 years). Left ventricular ejection fraction was normal in 60 of 75 (80%) patients and abnormal in 15 (20%). In patients with systolic dysfunction, mean ejection fraction was 31 ± 15% (range 10% to 50%). Of 75 unoperated patients, 66 (88%) had comorbidities and 49 (74%) had multiple comorbidities; 30 patients had undergone previous open-heart surgery. Symptoms of AS were present in 53 (71%) of 75 patients. In descending order were symptoms of heart failure in 29 patients, symptoms of heart failure and angina in 12, syncope or presyncope in 7, and angina alone in 5. Although there were more elderly symptomatic than asymptomatic patients (28% vs. 18% 80 years), mean age did not differ between groups (68.0 ± 15.5 years vs. 68.3 ± 14.1 years). The number of comorbidities in symptomatic and asymptomatic patients was not significantly different (2.6 ± 1.9 vs. 2.1 ± 1.6, p = 0.28). Of 22 asymptomatic patients, exercise testing was performed in only 1. Of 75 patients with unoperated severe AS, 69 (92%) were evaluated by a cardiologist and 32 (43%) by a cardiothoracic surgeon.
For 75 unoperated patients, calculated operative risk was 9.6 ± 11.8%. Operative risk was significantly lower among asymptomatic patients (5.1 ± 4.2%, range 0.9% to 14.8%) than among symptomatic patients (11.5 ± 13.4%, range 0.9% to 52.2%, p = 0.03). Operative risk was <5% in 25 (47%) of 53 symptomatic patients and <10% in 34 patients (64%), and was 20% in 11 patients (21%) and 40% in 5 patients (9%). Among 30 symptomatic patients for whom prohibitive operative risk was cited as the major rationale against AVR, calculated operative risk was <5% in 11 (37%) and <10% in 17 (57%); only 6 (35%) of these 17 were evaluated by a surgeon.
Reasons that AVR was not performed are shown (Table 1). Among 22 asymptomatic patients, the most common reason was asymptomatic status. One of these patients was documented to have no significant physical activity, and one is a paraplegic. Medical contraindications included cancer and past history of stroke. Exercise testing was performed in only 2 of 11 patients in whom symptoms were attributed to another etiology.
Follow-up was available at 8.7 ± 7.7 (range 0 to 23.5) months after the echocardiogram. Survival is shown (Fig. 1). Eighteen patients died (average interval 4.3 ± 4.8 months after the echocardiogram, range 0 to 14.2 months). Only 1 death was in a patient who was asymptomatic. One patient died of cancer; the remaining 17 died of complications related to AS.
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Figure 1 Survival of Patients With Unoperated AS
Kaplan-Meier survival for patients with unoperated severe aortic stenosis (AS). Survival estimates ± 1 standard error; log-rank difference in survival p = 0.01.
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In this survey, approximately half of patients with severe AS underwent AVR; this ratio is similar to the EuroHeart survey (6). Almost three-quarters of unoperated patients were symptomatic. Although the absence of symptoms was the most common reason that AVR was not performed in asymptomatic patients, inactivity was documented in several cases, and provocative stress testing was rarely used. Among symptomatic patients, comorbidities were felt to preclude AVR in over half. Calculated operative risk was very high in some patients, but did not appear prohibitive in many others. Operative risk was <10% in more than half of symptomatic patients in whom prohibitive risk was cited as precluding AVR, and fewer than one-third of these were referred to a surgeon. Lack of familiarity with current operative risks may have led nonsurgeons to overestimate risk, potentially denying patients access to surgery that was feasible. The prognosis for unoperated severe symptomatic AS was very poor, reinforcing the role of intervention. Although testing is still preliminary, less invasive delivery of devices for the treatment of severe AS may find a role in patients with truly prohibitive operative risk.
It could be attractive to assume that these data are unique to a single institution. However, the surveyed institution has an active program in the treatment of valvular heart disease. The authors believe that these findings are likely reflective of general practice.
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Footnotes
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Please note: supported by a grant from Edwards Lifesciences, LLC, Irvine, California.
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References
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1. Bonow RO, Carabello B, De Leon AC, et al. ACC/AHA guidelines for the management of patients with valvular heart disease J Am Coll Cardiol 1998;32:1486-1582.[Free Full Text]2. Bonow RO, Carabello B, Chatterjee K, et al. ACC/AHA 2006 guidelines for the management of valvular heart disease J Am Coll Cardiol 2006;48:e1-e148.[Free Full Text] 3. Charlson E, Legedza AT, Hamel MB. Decision-making and outcomes in severe symptomatic aortic stenosis J Heart Valve Dis 2006;15:312-321.[Web of Science][Medline] 4. Varadarajan P, Kapoor N, Bansal RC, Pai RG. Survival in elderly patients with severe aortic stenosis is dramatically improved by aortic valve replacement: results from a cohort of 277 patients aged 80 years Eur J Cardiothorac Surg 2006;30:722-727.[Abstract/Free Full Text] 5. Iung B, Cachier A, Baron G, et al. Decision-making in elderly patients with severe aortic stenosis: why are so many denied surgery? Eur Heart J 2005;26:2714-2720.[Abstract/Free Full Text] 6. Iung B, Baron G, Butchart E, et al. A prospective survey of patients with valvular heart disease in Europe: the Euro Heart Survey on Valvular Heart Disease Eur Heart J 2003;24:1231-1243.[Abstract/Free Full Text] 7. Roques F, Michel P, Gladstone AR, Nashef SAM. The logistic EuroSCORE (letter) Eur Heart J 2003;24:1-2.[Free Full Text]
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