LAUSR

Objectives: To assess the frequency and implications of mitral valve (MV) surgery at the time of septal myectomy (SM) for hypertrophic cardiomyopathy (HCM) in a national cohort. Patients and Methods: The National Inpatient Sample (NIS) was used to analyze surgical outcomes in patients with HCM undergoing SM from January 1, 2003, through December 31, 2014. Univariate analyses were used to compare patients undergoing SM with vs without concomitant procedures, and logistic regression was used to determine factors associated with prolonged length of stay (LOS) and in‐hospital mortality. Numeric values of 10 or less were not reported per NIS data use agreements. Results: The national cohort included 1174 adults with a primary diagnosis of HCM undergoing SM. Overall mean ± SD age was 54.4±14.5 years, and 45% of patients (n=529) were male. Isolated SM was performed in 67% (n=786), and the remainder had concomitant cardiac procedures, most frequently MV repair/replacement (22%, n=257). Median LOS was increased in those with concomitant MV surgery, 7 days, compared with isolated SM, 6 days (P<.001). Overall hospital mortality was 2.9% (n=34) and was lowest in those undergoing isolated SM (<1%; P<.001). In otherwise isolated SM, MV replacement increased likelihood of in‐hospital death (odds ratio, 12.0; 95% CI, 3.9‐36.5; P<.001) on a univariate basis. Conclusion: Intervention on the MV is more common nationally than in specialized centers, and the addition of MV replacement and other concomitant cardiac procedures was associated with increased rates of hospital mortality and LOS compared with patients undergoing isolated SM. These results suggest that concomitant MV intervention is associated with increased risk.