Peripheral microvascular function and long-term cardiovascular outcomes after percutaneous coronary intervention in patients with obstructive coronary artery disease

Background Coronary artery disease (CAD) patients remain at substantial risk of recurrent ischemic symptoms and adverse cardiovascular events even after successful percutaneous coronary intervention (PCI), partly due to persistent endothelial and microvascular dysfunction. Although flow-mediated dilation evaluates conduit artery endothelial function, skin post-occlusive reactive hyperemia (PORH) provides a complementary assessment of systemic microvascular reactivity through multiple vascular pathways. Purpose The purpose of this study was to determine whether impaired skin PORH response is associated with long-term composite cardiovascular outcomes in patients with chronic CAD undergoing PCI. Methods This retrospective cohort study included patients with obstructive coronary artery disease who underwent percutaneous coronary intervention and baseline assessment of skin microvascular function using post-occlusive reactive hyperemia (PORH). Clinical characteristics, laboratory data, and angiographic findings were collected, and participants were followed for long-term cardiovascular outcomes, including cardiac death, non-fatal myocardial infarction, stroke, and ischemia-driven revascularization. Patients were stratified according to the median PORH index, and propensity score matching was performed to reduce baseline imbalance. Time-to-event outcomes were evaluated using Kaplan–Meier analysis and multivariable Cox proportional hazards models with adjustment for relevant clinical covariates. Results Patients with a lower PORH index had a higher burden of cardiovascular risk factors and experienced a significantly greater incidence of long-term composite cardiovascular events compared with those with a higher PORH response. A higher PORH index was independently associated with a reduced risk of composite cardiovascular outcomes in both the overall cohort (adjusted HR 0.422) and the propensity score–matched cohort (adjusted HR 0.331), which was also supported by Kaplan–Meier analyses. Although individual event components and ischemia-driven revascularization showed similar trends, these differences did not reach statistical significance. Conclusions In the present study, a higher PORH index was independently associated with a lower risk of long-term composite CV events in patients with obstructive CAD undergoing PCI, and this inverse association remained robust after PSM. Notably, the composite endpoint incorporated both hard clinical events and ischemic-driven TLR or TVR, reflecting clinically relevant residual ischemic risk after PCI. Patients with a lower PORH index exhibited a higher burden of traditional cardiovascular risk factors, including hypertension, diabetes mellitus, chronic kidney disease, prior stroke, and microalbuminuria, consistent with the concept that impaired skin microvascular reactivity reflects a more adverse systemic vascular risk profile.