The coronary angiography-derived index of microcirculatory resistance predicts perioperative myocardial injury in stable coronary artery disease patients undergoing PCI.

Background: Coronary microvascular dysfunction (CMD) assessed by the index of microcirculatory resistance (IMR) is associated with perioperative myocardial injury (PMI).The angiographically derived index of microcirculatory resistance (caIMR) represents a novel and accurate alternative to IMR.

Objective: This study aims to evaluate the predictive ability of caIMR for PMI in patients with stable coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI).

Methods: Consecutive patients with stable CAD undergoing elective PCI of a single lesion were recruited. caIMR was measured before and after revascularisation, and total creatine kinase-MB (CK-MB) and high-sensitivity troponin T (hsTnT) levels were measured before and within 24 h after PCI.

Results: A total of 65 patients were enrolled and 26 patients fulfilled the diagnostic criteria for PMI. Post-PCI caIMR values were significantly higher in the PMI group than in the control group (27.02 ± 3.70 vs. 15.91 ± 3.43U,  < 0.001). Pearson correlation analysis showed that increased post-PCI caIMR values had a significant positive correlation with peak hsTnT (r = 0.803,  < 0.001) and peak CK-MB (r = 0.512, P = 0.001). Multivariate logistic regression analysis showed that post-PCI caIMR was an independent predictor of PMI (OR,1.731; 95 % CI:1.348-2.023;  < 0.001).ROC analysis suggested that the best cut-off value of post-PCI caIMR was 25.17U to diagnose PMI (AUC = 0.951, sensitivity 88.5 %, specificity 97.1 %). During a median follow-up 16 months, patients with PMI had a higher incidence of major adverse cardiovascular events (MACE) (42.31 % vs 5.13 %,  = 0.04).

Conclusions: Post-PCI caIMR can accurately predict PMI and clinical outcomes in stable CAD patients undergoing elective PCI, which supports the use of caIMR in clinical practice.