Prognostic value of systemic blood pressure response during exercise in a community-based patient population with hypertrophic cardiomyopathy

OBJECTIVES The present study was designed to prospectively evaluate the pro gnostic relevance of abnormal blood pressure response to exercise (ABPR), d efined as hypotension or failed blood pressure increase (<20 mm Hg) with ex ercise, in a community-based hypertrophic cardiomyopathy (HCM) population r epresentative of the overall disease spectrum. BACKGROUND Abnormal blood pressure response to exercise has been proposed a s a marker for hemodynamic instability and increased risk for disease-relat ed mortality in highly selected patient populations with HCM. MEHTODS The study population comprised 126 patients (aged 42 +/- 14 years) who underwent maximal symptom-limited cycloergometer exercise testing as pa rt of the standard evaluation at our institution, and who were followed sys tematically for 4.7 +/- 3.7 years after testing. RESULTS Of the 126 study patients, 98 (78%) had a normal blood pressure res ponse during exercise, whereas the other 28 (22%) had ABPR, including nine with hypotension and 19 with failed blood pressure rise. During the follow- up period, nine patients (7%) died of HCM-related causes (three suddenly an d six heart failure-related), of whom four had ABPR. In those patients aged less than or equal to 50 years, survival analysis after exercise testing s howed a significantly increased risk for cardiovascular mortality associate d with ABPR compared with a normal exercise response (p = 0.04), with an od ds ratio of 4.5 (95% confidence interval: 1.1, 20.1). However, ABPR showed low positive predictive accuracy for cardiovascular mortality (i.e., 14%), whereas negative predictive accuracy was high (i.e., 95%). CONCLUSIONS A hypotensive blood pressure response during exercise occurred in over 20% of a community-based patient cohort with HCM, and was associate d with adverse long-term prognosis in patients <50 years old. However, the positive predictive accuracy of this blood pressure response is too low to justify modifications of clinical management or to allow identification of the high-risk patient based solely on an abnormal test result. By virtue of its high negative predictive accuracy for HCM-related mortality, the blood pressure response to exercise appears to be most valuable (in conjunction with the absence of other well recognized risk factors) as a screening test for the identification of low-risk subsets of patients. (C) 1999 by the Am erican College of Cardiology.