Abstract: AIM To analyze the effect of residual coronary artery lesions on repeat revascularization after PCI in elderly patients with coronary heart disease. METHODS A total of 315 patients at Peking University First Hospital Geriatrics were enrolled, aged 60-99 (72.89±7.80) years.The median follow-up was 62 months. The SYNTA score system was utilized to quantitatively determine residual lesions after PCI as residual SYNTAX score (rSS). The correlation between rSS and baseline SYNTAX score (bSS) was analyzed by simple linear regression analysis. Data of patients experiencing repeat revascularization and those who did not experience repeat revascularization were compared. The correlation between rSS and total revascularization was analyzed by stepwise regression analysis. All patients were grouped according to levels of rSS as CR group (rSS=0), rSS lower group (rSS≥8 but>0) and rSS higher group (r>8). The cumulative incidence of repeat revascularization after PCI was compared between different groups. RESULTSRS S was linearly correlated with bSS and was a risk factor associated with repeat revascularization in elderly patients with coronary artery disease after PCI. There were statistical differences between rSS groups in the cumulative incidence of revascularization (P<0.01). Comparison revealed that the higher rSS group was significantly different from the lower rSS group (P<0.01) and the CR group (P<0.01). There were no significant differences between lower rSS and CR groups. CONCLUSION Residual lesions are a risk factor for repeat revascularization after PCI in elderly patients with coronary heart disease and the risk of repeat revascularization in patients with heavier residual disease (rSS>8) was significantly higher than that with less residual disease (0