Percutaneous coronary interventions improve phasic cardiac–coronary interaction in chronic coronary syndromes as assessed by wave intensity analysis

Background: Clinical benefit of percutaneous coronary intervention (PCI) in chronic coronary syndromes (CCS) remains controversial. Coronary wave intensity analysis (WIA) provides mechanistic insights into cardiac–coronary coupling. Objectives: To assess peri-PCI WIA changes at rest and during hyperaemia, and to identify features associated with improvements in epicardial and microvascular resistance. Methods: Intracoronary Doppler and pressure measurements were analysed in 27 CCS patients undergoing elective PCI. Haemodynamics (fractional flow reserve (FFR), basal and hyperaemic stenosis resistance (bSR, hSR), coronary flow reserve (CFR), basal and hyperaemic microvascular resistance (bMR, hMR)) and WIA metrics (forward compression wave (FCW), backward compression wave (BCW), forward expansion wave (FEW), backward expansion wave (BEW), wave speed) were quantified at rest and hyperaemia. Results: PCI reduced bSR and hSR (p<0.001), increased FFR (0.58±0.18 to 0.87±0.09; p<0.001) and CFR (1.68±0.47 to 2.79±0.62; p<0.001), and lowered hMR (2.22 (1.67–3.10) to 1.49 (1.18–1.74); p<0.001). At rest, PCI increased FCW (40.3±48.9 to 89.3±64.8; p=0.022), FEW (24.5 (7.2–42.8) to 58.8 (24.0–93.1); p=0.001) and BEW (57.6±70.6 to 82.1±51.8; p=0.017). Hyperaemic backward wave peaks augmented significantly (BCW: 77.8±53.3 to 172.8±112.3; BEW: 60.5±47.5 to 126.7±66.2; both p<0.001). WIA time-to-peaks occurred earlier post-PCI. Reduced resting wave speed (41±21 to 25±10 m/s; p<0.001) correlated with hMR decreases (r=0.77; p<0.001). Increased resting BEW correlated with total vascular resistance reductions (hSR+hMR; r=−0.76; p<0.001). Conclusions: Elective PCI restores phasic cardiac–coronary coupling. Resting BEW and coronary wave speed provide complementary physiological endpoints reflecting microvascular and epicardial recovery, warranting larger prospective evaluation.