Predictive Efficacy of the Index of Microcirculatory Resistance for Acute Allograft Rejection and Cardiac Events After Heart Transplantation: A Systematic Review and Meta-Analysis

Abstract

Background: In patients treated by heart transplantation, the index of microcirculatory resistance (IMR) has been found to have predictive potential for subsequent acute allograft rejection (AAR) and long-time cardiac events. When consulting related literature, the studies mostly were single-center with small sample sizes. The question of whether IMR can be utilized as a predictive biomarker is becoming increasingly contentious. To confirm the predictive efficacy of IMR, researchers did a systematic review and meta-analysis. Method: From inception to April 2022, PubMed, EMBASE, Cochrane Library, Web of Science, Ovid, ProQuest, and Scopus systematically were searched. The results were presented as pooled ratio rate (RR) with 95% confidence intervals (CI). Assessment of the quality, heterogeneity analyses, and publication bias analysis also were performed. Results: A total of 616 patients were studied in five trials. There were significant differences in subsequent AAR (RR = 4.08; 95% CI: 2.69~6.17; P = 0.000) or long-time cardiac events (RR=2.14; 95% CI: 1.44~3.19; P = 0.000) between IMR-high and IMR-low patients in the forest plots. Patients treated with heart transplantation in the high IMR group had better predictive efficacy than the low IMR group. Conclusions: High IMR could predict the events of subsequent AAR and cardiac events after heart transplantation. This will help reduce the occurrence of adverse events and personalize treatment for patients.

Heart Transplantation

“…The clinical picture varies from asymptomatic with findings on endomyocardial biopsy to cardiogenic shock. Studies show that patients with microcirculatory resistance index [65], donors with macrophages with activated C-C chemokine receptor 2 (CCR2) and myeloid differentiation primary response protein 88 (MYDD8) [66], increased left ventricle posterior wall thickness (1 mm increases 66%) and increased left ventricle mass index (1 g/m 2 , the chance increases 2.7%) [66,67], have an increased chance of rejection. Three types of rejection have been identified, which are described below.…”

Microcirculatory Disease in Patients after Heart Transplantation

“…In the multivariate analysis, only baseline IMR ≥ 16.0 was independently associated with AAR during the first year, demonstrating a high negative predictive value (96.7%). Moreover, in the meta-analysis, including 616 patients from five trials, the authors assessed the predictive potential of IMR for subsequent AAR and long-time cardiac events [35]. Both the risk of AAR (RR: 4.08; 95% CI: 2.69-6.17; p < 0.001) and long-term cardiac events (RR: 2.14; 95% CI: 1.44-3.19; p < 0.001) was significantly higher in IMR-high compared to IMR-low group.…”