Carbon Monoxide Diffusing Capacity Predicts Cardiac Readmission in Patients Undergoing Left Ventricular Assist Device Implantation

Abstract

The use of a left ventricular assist device (LVAD) is an effective therapeutic option for advanced heart failure. Patients with heart failure have impaired carbon monoxide diffusing capacity (DLco), which has not been well investigated in the LVAD population. Thus, we explored the predictive value of preoperative DLco in the survival and cardiac readmission rates in patients undergoing LVAD implantations in Japan. Patients who (i) received continuous-flow LVAD as bridge-to-transplant therapy from November 2007 to September 2018 at our institution, (ii) were more than 16 years old, (iii) were not converted from extracorporeal LVAD (iv) survived until discharge, and (v) underwent pulmonary function tests before LVAD implantation were included. The eligible patients were divided into 2 groups according to preoperative percent of predicted DLco (%DLco).The primary endpoints were all-cause death and hospital readmission for heart failure or arrhythmia (cardiac readmission). We retrospectively examined the records of 76 patients, resulting in 45 patients in the low DLco group (%DLco <80%) and 31 patients in the high DLco group (%DLco ≥80%). The 2-year cardiac readmission rate was 33.5% of the patients in the low DLco group and 8.7% in the high DLco group (p = 0.028). However, the mortality rate was not different between the two groups. %DLco was found to be associated with cardiac readmission in the univariate and multivariate analyses (hazard ratio 4.32, 95% confidence interval 1.50-15.9, p = 0.005). Low %DLco is a risk factor of cardiac readmission in patients undergoing LVAD implantation.