Functional residual ischemia and ventricular function drive symptomatic outcomes after PCI

Background/Introduction Incomplete revascularization after percutaneous coronary intervention (PCI) is commonly assessed using the residual Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score (rSS), an anatomical measure of residual coronary artery disease. The residual Functional SYNTAX score (rFSS), incorporating ischemia-producing lesions, may better reflect clinically relevant residual disease. The comparative impact of anatomical versus functional residual disease on symptom improvement remains unclear. Purpose To compare the association of anatomical residual disease (rSS) and functional residual disease (rFSS) with symptomatic improvement after PCI. Methods Consecutive patients with at least Canadian Cardiovascular Society (CCS) angina class II undergoing PCI between October 2018 and December 2019 at a general hospital were evaluated (n=236). Offline Quantitative Flow Ratio (QFR) analysis was estimated for each patient. rSS was calculated according to the standard SYNTAX methodology to quantify the anatomical burden of residual coronary disease after PCI. The rFSS was derived by summing the individual SYNTAX scores only for residual lesions associated with ischemia, defined as vessel QFR ≤0.89. CCS improvement was defined as a reduction in CCS class at follow-up. Multivariable logistic regression models adjusted for age, sex, diabetes mellitus, left ventricular ejection fraction (EF), and glomerular filtration rate were constructed to assess the independent association of rSS and rFSS with symptomatic improvement. Results In the anatomical model, rSS was not independently associated with CCS improvement (OR 0.52, 95% CI 0.24–1.13; p=0.098), whereas EF was independently associated with symptomatic improvement (OR 1.07 per 1% increase, 95% CI 1.02–1.11; p=0.002). In the functional model, rFSS was independently associated with a reduced likelihood of CCS improvement (OR 0.29, 95% CI 0.09–0.88; p=0.028), while EF was no longer statistically significant. Conclusions Functional residual ischemia, but not anatomical residual disease, independently predicts reduced symptomatic improvement after PCI. These findings indicate that functional assessment of residual disease may provide additional information regarding symptomatic recovery beyond anatomical evaluation alone.