Predictors and differential prognostic impact of post-PCI coronary microvascular dysfunction endotypes in chronic coronary syndrome
T Watanabe, Y Kanaji, E Usui, H Ueno, K Sayama, T Watanabe, R Murakami, S Hiroi, K Hosokawa, T KakutaAbstract
Background
Coronary microvascular dysfunction (CMD) immediate post-percutaneous coronary intervention (PCI) is a heterogeneous condition comprising distinct "endogenous" and "classical" endotypes1. However, the specific determinants and long-term prognostic implications of these endotypes in chronic coronary syndrome (CCS) remain under-investigated.
Purpose
This study sought to identify the predictors of post-PCI CMD endotypes and evaluate their respective impacts on clinical outcomes.
Methods
We retrospectively analyzed 591 patients with CCS undergoing elective PCI with post-PCI comprehensive microvascular assessment. Post-PCI CMD (coronary flow reserve [CFR] < 2.0) was subclassified into endogenous (resting 1/transit-time > 1.85) and classical (resting 1/transit-time < 1.85) endotypes. The 1.85 cutoff was derived from the 29.3rd percentile of resting 1/transit-time values, corresponding to the distribution of impaired CFR. The primary endpoint was major adverse cardiac events (MACE), a composite of all-cause death, heart failure, and nonfatal myocardial infarction. The secondary endpoint was vessel-oriented composite outcomes (VOCO), a composite of target vessel related cardiac death, target vascular myocardial infarction and target vascular revascularization.
Results
Post-PCI CMD was present in 29.3% of patients (endogenous: 17.1%; classical: 12.2%). The endogenous endotype was associated with advanced age, female sex, and higher comorbidity, whereas classical CMD was characterized by an elevated index of microcirculatory resistance (IMR). Pre-PCI microvascular resistance reserve (MRR) was a robust independent predictor of post-PCI CMD. Over a median 4.75-year follow-up, classical CMD was independently associated with a significantly higher risk of MACE (Hazard Ratio [HR]: 1.84; 95% CI: 1.04–3.24; P=0.035), whereas endogenous CMD was not. In contrast, VOCO was independent of CMD status but was significantly predicted by post-PCI fractional flow reserve (HR: 0.0014; P=0.027).
Conclusions
Post-PCI CMD in CCS is a phenotypic mosaic. While pre-PCI MRR effectively predicts overall post-PCI microvascular impairment, only the classical endotype serves as a driver of long-term patient-oriented adverse events. These findings underscore the necessity of endotype-specific risk stratification to refine post-PCI management strategies.Distribution of post-PCI CMD endotypesKaplan-Meier curve for MACE