Cardiomyopathy
Results of Ventricular Septal Myectomy and Hypertrophic Cardiomyopathy (from Nationwide Inpatient Sample [1998–2010])

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Highlights

  • Higher postoperative mortality was found after VSM than reported in recent studies.

  • Age was predictive of higher postoperative mortality and complications.

  • Higher burden of co-morbidities predicted higher postoperative mortality and complications.

  • More postoperative complications were associated with longer LOS.

Ventricular septal myomectomy (VSM) is the primary modality for left ventricular outflow tract gradient reduction in patients with obstructive hypertrophic cardiomyopathy with refractory symptoms. Comprehensive postprocedural data for VSM from a large multicenter registry are sparse. The primary objective of this study was to evaluate postprocedural mortality, complications, length of stay (LOS), and cost of hospitalization after VSM and to further appraise the multivariate predictors of these outcomes. The Healthcare Cost and Utilization Project's Nationwide Inpatient Sample was queried from 1998 through 2010 using International Classification of Diseases, Ninth Revision, procedure codes 37.33 for VSM and 425.1 for hypertrophic cardiomyopathy. The severity of co-morbidities was defined using the Charlson co-morbidity index. Hierarchical mixed-effects models were generated to identify independent multivariate predictors of in-hospital mortality, procedural complications, LOS, and cost of hospitalization. The overall mortality was 5.9%. Almost 9% (8.7%) of patients had postprocedural complete heart block requiring pacemakers. Increasing Charlson co-morbidity index was associated with a higher rate of complications and mortality (odds ratio 2.41, 95% confidence interval 1.17 to 4.98, p = 0.02). The mean cost of hospitalization was $41,715 ± $1,611, while the average LOS was 8.89 ± 0.35 days. Occurrence of any postoperative complication was associated with increased cost of hospitalization (+$33,870, p <0.001) and LOS (+6.08 days, p <0.001). In conclusion, the postoperative mortality rate for VSM was 5.9%; cardiac complications were most common, specifically complete heart block. Age and increasing severity of co-morbidities were predictive of poorer outcomes, while a higher burden of postoperative complications was associated with a higher cost of hospitalization and LOS.

Section snippets

Methods

The study cohort was derived from the Nationwide Inpatient Sample (NIS) database from 1998 through 2010, a subset of the Healthcare Cost and Utilization Project sponsored by the Agency for Healthcare Research and Quality. The NIS is the largest publicly available all-payer inpatient care database in the United States, including data on approximately 7 million to 8 million discharges per year, and is a stratified sample designed to approximate a 20% sample of US community (nonfederal,

Results

Table 1 shows baseline characteristics of the study population. A total of 665 VSM procedures were available for analysis from 1998 to 2010. The mean age of the study cohort was 56.9 ± 0.6 years. Men constituted 40% of the cohort, with 52.8% being white. The mean CCI score for the cohort was calculated as 0.87 ± 0.04, with hypertension being the most common co-morbidity, present in 45.1% of the patients, while diabetes was present in 12.2% of those who underwent VSM. Most procedures were done

Discussion

Our study presents valuable real-world postprocedural data regarding VSM from the largest available inpatient care database. Postoperative mortality after VSM was noted to be high at 5.9% in our study on the basis a wide spectrum of real-world VSM experience from multiple community hospitals across the nation. Although earlier publications have reported similar13 and higher14 mortality rates, improving surgical experience has resulted in reductions in postoperative mortality and complication

Disclosures

The authors have no conflicts of interest to disclose.

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Drs. Panaich, Badheka, Chothani, and Mehta contributed equally to this report.

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