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Updated: Oct 10, 2025
Mouse Model of Alloimmune-induced Vascular Rejection and Transplant Arteriosclerosis
Published on: May 17, 2015
Microcirculatory Resistance Predicts Allograft Rejection and Cardiac Events After Heart Transplantation
Jung-Min Ahn1, Frederik M Zimmermann2, Lars Gullestad3
1Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford Cardiovascular Institute, Stanford, California, USA.
Background:
Single-center data suggest that the index of microcirculatory resistance (IMR) measured early after heart transplantation predicts subsequent acute rejection.
Objectives:
The goal of this study was to validate whether IMR measured early after transplantation can predict subsequent acute rejection and long-term outcome in a large multicenter cohort.
Methods:
From 5 international cohorts, 237 patients who underwent IMR measurement early after transplantation were enrolled. The primary outcome was acute allograft rejection (AAR) within 1 year after transplantation. A key secondary outcome was major adverse cardiac events (MACE) (the composite of death, re-transplantation, myocardial infarction, stroke, graft dysfunction, and readmission) at 10 years.
Results:
IMR was measured at a median of 7 weeks (interquartile range: 3-10 weeks) post-transplantation. At 1 year, the incidence of AAR was 14.4%. IMR was associated proportionally with the risk of AAR (per increase of 1-U IMR; adjusted hazard ratio [aHR]: 1.04; 95% confidence interval [CI]: 1.02-1.06; p < 0.001). The incidence of AAR in patients with an IMR ≥18 was 23.8%, whereas the incidence of AAR in those with an IMR <18 was 6.3% (aHR: 3.93; 95% CI: 1.77-8.73; P = 0.001). At 10 years, MACE occurred in 86 (36.3%) patients. IMR was significantly associated with the risk of MACE (per increase of 1-U IMR; aHR: 1.02; 95% CI: 1.01-1.04; P = 0.005).
Conclusions:
IMR measured early after heart transplantation is associated with subsequent AAR at 1 year and clinical events at 10 years. Early IMR measurement after transplantation identifies patients at higher risk and may guide personalized posttransplantation management.
