Predictors of N-Terminal Pro-Brain Natriuretic Peptide Nonresponse and Its Impact on Outcomes in Patients After Septal Myectomy.

Abstract

Hypertrophic cardiomyopathy (HCM) often presents with elevated N-terminal pro-brain natriuretic peptide (NT-proBNP). Although septal myectomy is the gold standard for treating obstructive HCM, changes in NT-proBNP levels after surgery vary, with some patients experiencing increased levels. This study evaluated changes in NT-proBNP after myectomy, identified predictors of nonresponse, and assessed the effect of nonresponse on outcomes. We analyzed 375 patients with HCM who underwent presurgical and postsurgical myectomy NT-proBNP testing between 2011 and 2020. NT-proBNP nonresponse was defined as (1) a decrease of <30% or an increase in NT-proBNP if baseline NT-proBNP was abnormal, or (2) postmyectomy NT-proBNP becoming abnormal if baseline was normal. Clinical, echocardiographic, surgical, and follow-up data were compared between nonresponders and responders. A total of 140 patients (37.3%) were nonresponders. Compared with responders, nonresponders had a higher prevalence of diabetes mellitus (DM; P = .008). They also had a lower left ventricular outflow tract gradient, thicker interventricular septum, and more midventricular obstruction (all P ≤ .05). Nonresponders had lower preoperative but higher postmyectomy NT-proBNP levels. Predictors of nonresponse included DM, midventricular obstruction, preoperative septal thickness, left ventricular outflow tract gradient, left atrial diameter, and NT-proBNP levels. Nonresponders had more advanced follow-up heart failure (P < .001), higher midterm all-cause mortality (P = .007), and a higher incidence of the composite end point of all-cause mortality and cardiovascular rehospitalization (hazard ratio, 2.46; 95% CI, 1.17-5.17; P = .018). DM, septal thickness, and midventricular obstruction predicted nonresponse to NT-proBNP after myectomy, indicating worse outcomes and necessitating closer postoperative monitoring.