Clinical Characteristics and Outcome of Alcohol Septal Ablation With Confirmation by Nitroglycerin Test for Drug-Refractory Hypertrophic Obstructive Cardiomyopathy With Labile Left Ventricular Outflow Obstruction

摘要

Careful evaluation, including provocation tests, is needed to specify an indication for septal reduction therapy in patients with drug-refractory hypertrophic obstructive cardiomyopathy. This study aimed to evaluate the outcome of alcohol septal ablation (ASA) using an intravenous nitroglycerin test (IV-NTG). Of consecutive 156 patients, after excluding cases of severe valvular disease and repeat septal reduction therapy, we investigated the clinical characteristics of patients with labile obstruction (n = 32) and the outcomes after ASA using the IV-NTG test; comparisons were made with those exhibiting basal obstruction (a resting gradient of 30 mm Hg). The patients with labile obstruction had less left ventricular mass (141 +/- 47 vs 182 +/- 59 g, p = 0.003) and less brain natriuretic peptide values (414 +/- 576 vs 744 +/- 625 pg/ml, p <0.001) than those with basal obstruction. Immediately after ASA, the gradients improved from 15 +/- 7 to 5 +/- 5 mm Hg and the IV-NTG-provoked gradients improved from 74 +/- 25 to 13 +/- 9 mm Hg, respectively. At 1-year follow-up, the New York Heart Association functional class had improved from 2.7 +/- 0.5 to 1.3 +/- 0.5. There was no sudden cardiac death during the follow-up period (5.1 +/- 3.0 years), and 8-year survival free from cardiovascular death was 94%. In conclusion, patients with labile obstruction had less-severe left ventricular hypertrophy but exhibited symptoms comparable to those with basal obstruction. The IV-NTG test is a useful method for rapidly confirming acute reduction of the latent gradient after the ASA procedure, and the outcome of ASA for labile obstruction was favorable. (C) 2015 The Authors. Published by Elsevier Inc.