Septal Ablation and Hypertrophic Obstructive Cardiomyopathy: 7 Years US Experience

BACKGROUND: Septal ablation (SA) is a key modality for left ventricular outflow tract gradient reduction in hypertrophic obstructive cardiomyopathy (HOCM) patients with refractory symptoms. The primary objective of our study was to evaluate post-procedural mortality, complications, length of stay (LOS), and cost of hospitalization following SA. METHODS: We queried the Nationwide Inpatient Sample (NIS) between 2005 and 2011 using the ICD9 procedure code of 37.34 for ablation of heart tissue. Only adult patients with HOCM (ICD-9-CM: 425.1) were included. Patients with any arrhythmia diagnosis or open surgical ablation procedure code were excluded. Hierarchical mixed effects models were generated in order to identify the independent multivariate predictors of outcomes. RESULTS: A total of 358 SAs were available for analysis. There was no reported mortality during the study period; permanent pacemaker implantation rate was 8.7%. Highest hospital volume tertile (OR, 95%CI, P- value) predicted significantly lower post-procedural complications (0.51, 0.26-0.98, P = 0.04). Univariate analysis of highest versus lowest tertile of hospital volume showed significant decrease in LOS (2.6 days vs. 3.8 days, P<0.01) and non-significant decrease hospitalization costs (16,800$ vs. 19,500$, P = 0.29). CONCLUSIONS: SA is a safe procedure and associated with low peri- procedural mortality rate. A higher burden of baseline comorbidities is associated with worse outcomes while higher annual hospital volume is associated with lower rate of post-procedural complications, length of stay, and cost of care following SA.