Impact of Annual Hospital Volume on Outcomes after Left Ventricular Assist Device (LVAD) Implantation in the Contemporary Era

Abstract

Introduction: There are few data in the literature regarding impact of annual hospital volume on outcomes such as mortality and length of stay (LOS) post-LVAD implantation.

Methods: We queried the nationwide inpatient sample from 2008 to 2011 using International Classification of Diseases, 9th Revision procedure code 37.66. We included patients ≥18 years without primary diagnosis of orthotopic heart transplant. Annual volume of LVAD implantation was computed for each hospital. Multivariable hierarchical mixed effect logistic regression models were used to determine predictors of in-hospital mortality and LOS.

Results: There were 1749 LVAD implants from 2008 to 2011; patients had a mean age of 55.4 years, and 23% were female. In-hospital mortality decreased from 20.9% in the first tertile (1-22 LVADs/y) to 13.7% in the third tertile (≥35 LVADs/y) of hospital volume. Median LOS decreased from 34 days in the first tertile to 28 days in third tertile of hospital volume. The adjusted odds ratios of the highest tertile of hospital volume in predicting in-hospital mortality and LOS were 0.41 (0.26-0.64, P < .001) and 0.41 (0.23-0.73, P = .003), respectively. Restricted cubic spline analysis showed that a volume threshold of >20 LVADs/year was associated with favorable mortality rates of <10%.

Conclusions: High annual LVAD volume is associated with significantly decreased in-hospital mortality and LOS after LVAD implantation. Center experience is an important determinant of optimal patient outcomes.

Keywords: Left ventricular assist device (LVAD); annual hospital volume; continuous flow devices.