Effect of Ischemic Time on Immediate Post-Transplant Heart Rate and Chronotropic Agent Use

Abstract

Background It is unclear if the ischemic time affects the heart rate and the use of vasoactive peptides in the immediate postoperative period. It is hypothesized that prolonged ischemic time can decrease the mean heart rate and increase the requirement of chronotropic and inotropic agents, in terms of dose as well as duration. Methods Retrospective review of adult patients who underwent orthotopic heart transplantation from 2011 to 2018 at Jewish Hospital, Louisville, Kentucky. Results Of the total 77 patients, 9 patients died on-average 401 days post-transplant. The cohort was divided into 2 groups based on the median ischemic time of 162 minutes. Mean heart rate was similar in both groups however, patients with longer ischemic time (≥162 minutes) required higher total epinephrine dose in the immediate postoperative period (days 3rd and 5th). On postoperative day 7 (POD#7), higher ischemic time correlated with more number of chronotropic agents (p=0.039) [figure 1]. Patients persistently on at least one catecholamine agent on POD#7 were more likely to die during prolonged post-discharge follow up (36% vs. 8%, p= 0.035). Expired patients consistently required higher doses of epinephrine in the early postoperative period (p=0.001). Discussion The study found longer ischemic time correlated with difficulty in weaning chronotropic and inotropic peptides in the immediate postoperative period needing increased intensive care unit stay and hospitalization cost. Despite the significantly longer vasoactive peptide use, the mean heart rates were similar in both groups. This could indicate an independent ability to maintain heart rate among shorter ischemic time patients.