Prevalence, determinants, and prognostic significance of exercise-induced pulmonary hypertension in patients with hypertrophic cardiomyopathy.

Exercise-induced pulmonary hypertension (EIPH) is associated with worse outcomes in patients with heart failure or valvular heart disease. However, little is known regarding the implications of EIPH in hypertrophic cardiomyopathy (HCM) patients. We retrospectively reviewed data of consecutive HCM patients who underwent clinically indicated exercise echocardiography using a semi-supine bicycle ergometer at our hospital. EIPH was defined as pulmonary artery systolic pressure ≥ 60 mmHg during exercise. The incidences of HCM-related mortality and HCM-related morbidity during follow-up period were evaluated. Of 42 patients (mean age 59 ± 21 years; 4 with resting obstruction, 19 with provoked obstruction, and 19 without obstruction), 16 (38%) developed EIPH. Patients with EIPH had significantly longer resting E wave deceleration time (271 ± 116 vs. 213 ± 66 ms; P = 0.04), higher resting pulmonary artery systolic pressure (35 ± 6 vs. 31 ± 5 mmHg; P = 0.04), and higher B-type natriuretic peptide level (283 [222, 465] vs. 142 [54, 423] pg/ml; P = 0.04) than those without EIPH. Kaplan-Meier curve analysis demonstrated that EIPH was significantly associated with HCM-related morbidity (log-rank; P = 0.01). In Cox regression analysis, EIPH was a significant predictor of HCM-related morbidity (hazard ratio: 5.98, 95% confidence interval 1.36-41.07; P = 0.02). In conclusion, EIPH was documented in about one-third of HCM patients. EIPH was a significant predictor of HCM-related morbidity in patients with HCM.