Abstract 15799: Frequency and Etiology of Post-Operative Leukocytosis After Heart Transplantation

Abstract

Introduction: Many factors contribute to post-operative leukocytosis after heart transplantation; it may be challenging to determine whether post-operative leukocytosis is caused by infection. Objective: To describe the frequency and causes of leukocytosis after heart transplantation. Methods: A representative sample of 207 of 308 patients who underwent heart transplant at our institution between 1/1/17 and 12/31/22 was examined. Leukocytosis was defined as a white blood cell (WBC) count peak >11 th/μL or a 30% increase in WBC if pre-transplant baseline was >11 th/μL. Leukocytosis was classified as early (post operative day [POD] 0-3), delayed (POD 4-7), or late (POD 8-60). Culture, biopsy, and other clinical data were used to adjudicate etiology. Groups were compared using χ 2 , Fisher’s, or t-test as indicated. Results: The sample was 27% female with a mean age of 51.2 (±12.6) years. A total of 404 leukocytosis episodes were identified affecting 204 patients. Common etiologies included: post-transplant surgery (47.0%), true infection (27.2%), corticosteroid bolus (4.0%), subsequent surgery (3.5%), rejection (3.0%), and thrombus (3.0%). Delayed (24/47) and late (59/146) leukocytosis were more likely to be associated with infection than early leukocytosis (27/211, p<0.0001 for both comparisons). Common causes of infection were: pneumonia (33%), bloodstream infection (20%), skin and soft tissue (12%), unknown (9%), urinary (5%), and colitis (3%). Post-operative infection was associated with increased hospital length of stay after transplantation (17 vs 46 days, p<0.0001), and increased in-hospital mortality (9.6% vs 2.7%, p=0.040). ECMO (p=0.08), non-ECMO temporary mechanical circulatory support (p=0.70), prior cardiac surgery (p=0.08), and donor bloodstream infection (p=0.40) were not associated with post-operative infection. There was no significant difference in cross clamp time (p=0.42), ischemic time (p=0.27), or age (p=0.07) in patients with vs without infection. Conclusion: Leukocytosis after transplant is nearly universal. Patients developing leukocytosis on POD ≥4 have a high rate of concurrent infection compared to those with early leukocytosis, which is in turn associated with increased LOS and in-hospital mortality.