Paradigm has already shifted to ischemia-guided functional approach.

T he anatomic Synergy Between Percutaneous Coronary Intervention With TAXUS and Cardiac Surgery (SYNTAX) score is a stratification score illustrating the complexity of angiographic stenosis. It was considered a sur-rogate for poor prognosis after percutaneous coronary intervention (PCI). 1 Accordingly, in patients with a high baseline SYNTAX score (bSS) requiring coronary revascularization, coronary artery bypass graft surgery was chosen over PCI in the current guidelines. The mechanism by which bSS is a good surrogate for long-term prognosis is evident. Patients with a high bSS compared with those with a low bSS have more complex comorbidities such as old age, diabetes mel-litus, multiple stenoses, and low left ventricular function. Subsequently, they receive more complex procedures using multiple stents and devices. Since the SYNTAX score II was revised by taking into consideration clinical risk factors, the function of the scoring model in choosing between PCI and coronary artery bypass graft surgery and prognosis prediction has improved. The residual SYNTAX score (rSS), which is a variant of the SYNTAX score, was recently constructed to represent the extent of untreated coronary lesions after revascular-ization treatment. In the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) study, comprising patients with acute coronary syndrome, there was a stepwise increase in the rate of major adverse cardiac events, including death, myocardial infarction, and unplanned revasculariza-tion, in patients with an rSS of 0 5 In particular, for patients with an rSS >8, indicating incomplete revascularization (ICR) of multiple lesions after PCI, the mortality rate was significantly higher than in patients with an rSS ≤8. It is worth noting that subjects in the ACUITY study were not suitable to validate the predictive ability of rSS. Acute coronary syndrome patients enrolled in the ACUITY study may have been intentionally treated with a culprit angioplasty, without the goal of complete revascularization (CR). A retrospective angiographic analysis of the SYNTAX study by Farooq et al 6 in this issue of Circulation provides important information on whether the rSS has a good discriminatory power for predicting outcomes in patients presenting with relatively stable symptoms. Patients with an rSS of >8 had a higher risk of 5-year mortality (35.3%) than those with an rSS of 0 (8.5%), >0 to 4 (8.7%), and >4 to 8 (11.4%). Given these findings, rSS appears to be a validated angiographic score to represent the degree of ICR and to predict outcomes after PCI. Combined with the pre-dictive role …