The Impact Of Years Since Transplant On The Clinical Course After SARS-CoV-2 Infection In Heart Transplant Recipients

INTRODUCTION: The risk of Severe Acute Respiratory Syndrome - Coronavirus-2 (SARS-CoV-2) infection and mortality is higher in heart transplant (HT) recipients compared to immunocompetent individuals. The impact of years since transplant on clinical course risk is unknown. We evaluated the differences in clinical phenotypes and outcomes according to years since transplant in HT recipients with active SARS-CoV-2 infection. METHODS: Consecutive HT recipients from our National Transplant Centre with confirmed SARS-CoV-2 between April 2020 and March 2022 were enrolled in this retrospective observational study. Patients were stratified into 2 groups: <5 years after HT (Group A) and >/= 5 years after HT (Group B). RESULTS: A total of 63 HT recipients were enrolled [median age 56 (41,66) years, 32% female] with 33% of patients (n=21) assigned to Group A, and 67% (n=42) to Group B. In Group B patients, the prevalence of diabetes mellitus and cardiac allograft vasculopathy was significantly higher compared to those in Group A. Meanwhile, Group A patients were more likely to have a history of neutropenia prior to SARS-CoV-2 infection and were more frequently taking maintenance steroids and antimetabolite immunosuppressants (Table 1). Those recipients less than 5 years since HT were also significantly more likely than those >5 years out to develop the infection despite a 3(rd) dose of COVID vaccine (60% vs 31%, p 0.03).During the active infection, Group A recipients more frequently developed neutropenia (73% vs 27%, p 0.01), and trended towards higher rates of hospitalizations (57% vs 32%, p 0.06). Notably, none of the patients in Group A required mechanical ventilation compared to just under 10 % (n=4) of those in Group B. Further, no Group A patients died during the active infection hospitalization compared to 14% (n=6) of those in Group B. CONCLUSION: In HT recipients, years since transplant is a simple, clinically useful parameter stratifying outcomes after SARS-CoV-2 infection. While patients with less than 5 years since transplant are more likely to develop infection despite booster vaccination and require hospitalization, greater number of years since transplant was associated with more severe consequences during hospitalization.