Assessment of coronary microvascular dysfunction by angiography-based index of microcirculatory resistance: an indirect meta-analysis.

Introduction: There is a lack of consensus on diagnosing coronary microvascular dysfunction (CMD) using the angiography-based index of microcirculatory resistance (Angio-IMR) due to the absence of evidence. This study aims to explore the efficacy of Angio-IMR in diagnosing CMD.

Methods: A systematic search was conducted in PubMed, Embase, Scopus, and Cochrane Library for studies primarily focusing on Angio-IMR diagnosing CMD, using IMR as the gold standard. The primary results were pooled sensitivity, specificity, and the area under curve (AUC).

Results: A total of 15 studies involving 2202 individuals and 2330 vessels were included in our study, Angio-IMR demonstrated high performance in predicting IMR with overall pooled sensitivity and specificity of 0.84 (95% confidence interval (CI): 0.81 to 0.87) and 0.87 (95%CI: 0.83 to 0.99), respectively, and AUC=0.91 (95%CI: 0.89 to 0.94). This indicates that Angio-IMR has good diagnostic characteristics. Subgroup analysis by indirect meta-analysis showed higher sensitivity in the rest state. However, there is no significant difference in sensitivity and specificity between the hyperemic and rest states when using the AccuIMR system. Furthermore, sensitivity and specificity were more pronounced in the group without coronary pressure monitoring compared to the group with monitoring.

Conclusion: Angio-IMR is an alternative tool to identify CMD.