Predictive ability of microvascular resistance reserve for periprocedural myocardial injury in patients with stable coronary artery disease undergoing percutaneous coronary intervention

Periprocedural myocardial injury (PMI) has shown an association with worse prognosis after percutaneous coronary intervention (PCI). The microvascular resistance reserve (MRR) has been introduced as an index to evaluate microvascular vasodilatory capacity, independent of epicardial disease. Given the unclear association between MRR and PMI, this study aimed to determine the relationship between PMI and coronary microvascular dysfunction, including index of microcirculatory resistance (IMR) and MRR. This study identified 68 patients with stable angina pectoris who underwent PCI after measurements of coronary circulatory physiological indices at Hiroshima University Hospital between October 2017 and October 2024. PMI was assessed by a post-PCI high-sensitivity troponin T level > 5 times the 99th percentile of the normal upper limit (> 0.07 ng/mL). In total, 57 patients were enrolled, of which 18 (31.6%) had elevation of troponin T > 0.07 ng/mL after PCI and were classified into the PMI group. Significantly worse measurements of IMR (33.7 24.0–43.8 vs. 26.0 15.9–33.0, p = 0.029) and MRR (2.95 2.28–4.00 vs. 4.29 3.01–5.74, p = 0.009) were documented in the PMI group. After multivariable logistic regression analyses, both MRR (OR 0.464; 95% CI 0.234–0.919; p = 0.028) and IMR (OR 1.060; 95% CI 1.000–1.1830; p = 0.041) were identified as predictive factors of PMI. Both MRR and IMR before PCI were independent predictors of PMI.