Hospital Volume Outcomes After Septal Myectomy and Alcohol Septal Ablation for Treatment of Obstructive Hypertrophic Cardiomyopathy: US Nationwide Inpatient Database, 2003-2011.

Abstract

Previous data on septal myectomy (SM) and alcohol septal ablation (ASA) in obstructive hypertrophic cardiomyopathy have been limited to small, nonrandomized, single-center studies. Use of septal reduction therapy and the effect of institutional experience on procedural outcomes nationally are unknown. To examine in-hospital outcomes after SM and ASA stratified by hospital volume within a large, national inpatient database. This study analyzed all patients who were hospitalized for SM or ASA in a nationwide inpatient database from January 1, 2003, through December 31, 2011. Rates of adverse in-hospital events (death, stroke, bleeding, acute renal failure, and need for permanent pacemaker) were examined. Multivariate logistic regression analysis was performed to compare overall outcomes after each procedure based on tertiles of hospital volume of SM and ASA. Of 71 888 761 discharge records reviewed, a total of 11 248 patients underwent septal reduction procedures, of whom 6386 (56.8%) underwent SM and 4862 (43.2%) underwent ASA. A total of 59.9% of institutions performed 10 SM procedures or fewer, whereas 66.9% of institutions performed 10 ASA procedures or fewer during the study period. Incidence of in-hospital death (15.6%, 9.6%, and 3.8%; P < .001), need for permanent pacemaker (10.0%, 13.8%, and 8.9%; P < .001), and bleeding complications (3.3%, 3.8%, and 1.7%; P < .001) after SM was lower in higher-volume centers when stratified by first, second, and third tertiles of hospital volume, respectively. Similarly, there was a lower incidence of death (2.3%, 0.8%, and 0.6%; P = .02) and acute renal failure (6.2%, 7.6%, and 2.4%; P < .001) after ASA in higher-volume centers. The lowest tertile of SM volume among hospitals was an independent predictor of in-hospital all-cause mortality (adjusted odds ratio, 3.11; 95% CI, 1.98-4.89) and bleeding (adjusted odds ratio, 3.77; 95% CI, 2.12-6.70), whereas being in the lowest tertile of ASA by volume was not independently associated with an increased risk of adverse postprocedural events. In US hospitals from 2003 through 2011, most centers that provide septal reduction therapy performed few SM and ASA procedures, which is below the threshold recommended by the 2011 American College of Cardiology Foundation/American Heart Association Task Force Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy. Low SM volume was associated with worse outcomes, including higher mortality, longer length of stay, and higher costs. More efforts are needed to encourage referral of patients to centers of excellence for septal reduction therapy.