According to data from the United Network for Organ Sharing (UNOS), 3,552 orthotopic heart transplants (OHT) were performed in 2019. That’s up slightly from 3,408 the year before. After these transplants, one of the biggest concerns is acute rejection of the allograft. As a cardiac anesthesiologist, I’m tasked with ensuring that patients receive their induction dose of anti-rejection medications (usually a combination of steroids and antithymocyte globulin) in a timely manner. As an intensivist, I always have to keep acute rejection in the differential when patients become hemodynamically unstable following OHT.
These patients will also have endomyocardial biopsies looking for signs of acute cellular rejection (ACR) or antibody mediated rejection (AMR). These biopsies are initially frequent (weekly at most institutions) but spaced apart if the patient is clinically stable and the allograft’s histology is reassuring.
Here’s a table I created that summarizes some of the important grading criteria for ACR and AMR. 🙂