Waitlist Outcomes in Patients with Blood Group O during Continuous Flow Left Ventricular Assist Device Support

Abstract

Continuous flow left ventricular assist device (CF LVAD) supported patients with blood group O may wait longer for heart transplantation (HT), but it remains uncertain if during this waiting period such patients have greater morbidity and mortality from major adverse events (AEs). We conducted a UNOS database analysis of all patients that were waitlisted for HT after CF LVAD implantation from January 2006 to March 2019. Major demographics, waitlist times, waitlist mortality and occurrence of major AEs were retrieved. Patients were categorized as blood group O and non-blood group O. Post-transplant survival was also retrieved. Waitlist and post HT survival were assessed by Kaplan Meier analysis and Cox proportional hazard ratios were calculated. AEs during device support were compared by logistic regression. Overall, 8,578 patients with CF LVADs were placed on the UNOS waitlist during the study period. As expected, Blood group O (n=4,115) had longer waitlist times (412 days, IQR: 102-576; non-O 250 days, IQR 39-323 days, p<0.0001) than non-blood group O (n=4,461) patients. There were no significant differences between groups in age and gender. Blood group O had a higher likelihood of driveline infections (OR: 1.40, 95% CI 1.19-1.64, p<0.001) and life-threatening ventricular arrhythmias (OR: 2.22, 95% CI 1.44-3.42, <p=0.001, figure1A). Interestingly, waitlist mortality was similar in both groups (HR: 1.01, 95% CI 0.84-1.21, p=0.95, figure1B), as well as post HT survival (HR 0.96, 95% CI 0.85-1.09, p=0.58, figure1C). Despite more major AEs during CF LVAD support, patients with blood group O experience similar wait list and post HT survival.