Functional complete revascularization (CR) after percutaneous coronary intervention (PCI) as determined by classic residual functional SYNTAX score (c-rFSS) has been associated with improved prognosis. In this study, the c-rFSS algorithm is optimized for a novel modified rFSS (m-rFSS) and prognostic implications of this novel scoring is determined. The m-rFSS algorithm is updated for 2 clinical scenarios, i.e., 1) lesions with suboptimal functional results, and 2) angiographic diameter stenosis <
50% but functionally significant stenoses, which are not scored by c-rFSS. The major outcome is a 2-year major adverse cardiac event (MACE). A total of 1,555 patients analyzable for both c-rFSS and m-rFSS are included. After calculating m-rFSS, 12.0% (187/1,555) of patients with c-rFSS-based functional CR (c-rFSS = 0) are reclassified as having m-rFSS-based incomplete revascularization (IR, m-rFSS>
0)
thus, 377 (21.7%) patients have c-rFSS-based functional IR whereas 524 (33.7%) has m-rFSS-based IR. Patients with m-rFSS-based functional IR (m-rFSS>
0) show a significantly higher risk for major MACE outcome (20.8% vs 5.9%
adjusted hazard ratio 3.32, 95% confidence interval: 2.34-4.71) than patients with functional CR (m-rFSS = 0). The m-rFSS is more predictive of 2-year MACE than c-rFSS (difference in C-index 0.07, p <
0.001). In this study, we optimized the classic scoring algorithm to develop a novel scoring system (m-rFSS), and revascularization completeness determined by m-rFSS is markedly associated with a 2-year prognosis.