Abstract 18841: Outcomes of Septal Myomectomy in the United States: A 13-year perspective

Abstract

Background: Septal Myomectomy (MM) is the primary modality for left ventricular outflow tract (LVOT) gradient reduction in hypertrophic obstructive cardiomyopathy (HOCM) patients with refractory symptoms. Extended follow-up data for MM from a large multi-center registry is sparse. METHODS: We queried the Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample (NIS) between 1998 and 2010 using ICD9 procedure code 37.33 for MM. Only adult patients with HOCM (ICD-9-CM code 425.1) were included. Out of these, patients with any arrhythmia diagnosis were excluded. The NIS represents 20% of all hospitals in the US. We defined severity of co-morbidities using Deyo modification of Charlson co-morbidity index (CCI), where higher scores (0-33) represent increasing burden. Three level hierarchical mixed models were created to identify independent multivariate predictors of complications and mortality for MM. Hierarchical mixed effects linear regression models were used to evaluate cost of hospitalization and length of stay (LOS). RESULTS: The overall mortality was 5.9%. 5.4% of the patients had significant post-operative bleeding necessitating transfusion while 8.7% had complete heart block requiring a pacemaker. Increasing CCI was associated with a higher rate of complications and mortality (OR 2.42, 95% CI (1.17-4.98), p-value 0.02). The mean cost of hospitalization was $40,444 +/- 1,786 while the average LOS was 8.69 +/- 0.35 days. Occurrence of any post-operative complications was associated with an increased cost of hospitalization (+$33,870, p<.01) and LOS (+6.1 days, p<.01). Conclusions: We observed a relatively higher mortality rate for surgical MM than published literature with cardiac complications being most common specifically complete heart block. Increasing severity of co-morbidities was predictive of poorer outcomes while a higher burden of post-operative complications was associated with a higher cost of hospitalization and LOS.