Impact of Incomplete Revascularization on Long-Term Outcomes Following Chronic Total Occlusion Percutaneous Coronary Intervention

We aimed to evaluate the impact of incomplete revascularization (ICR) on long-term outcomes of patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Consecutive patients undergoing CTO PCI at 4 centers were included. Baseline SYNTAX score (bSS: low [≤ 22], intermediate [>22 and <33], high [≥33]), residual SYNTAX score (rSS: 0, >0 and ≤8, >8), and SYNTAX revascularization index (SRI: 100 × (bSS-rSS)/bSS: 100%, 50% to 99%, <50%) were calculated. The primary end point was major adverse cardiac events (MACEs; cardiac death, any myocardial infarction, any revascularization) on follow-up. Multivariable Cox regression analysis was conducted to identify predictors of MACEs. Overall, 686 patients were included (low bSS: n = 437; intermediate bSS: n = 187; high bSS: n = 62). Occlusion complexity, crossing strategies, and procedural success rates were similar across groups. The degree of ICR increased with higher bSS categories (rSS was 2.5 ± 4.7 in low vs 6.2 ± 9.3 in intermediate vs 9.1 ± 12.2 in high bSS, p <0.001). The SRI followed a similar pattern. Median follow-up was 781 (369 to 1,217) days. Three-year MACE rates increased with higher bSS and rSS, and decreasing SRI categories (bSS: low 19.4% vs intermediate 25.9% vs high 33.3%, p = 0.02), which was driven by a higher incidence of repeat revascularization. Compared with an rSS = 0, both an rSS >0 and ≤8 (hazard ratio 2.06, p = 0.004) and an rSS >8 (hazard ratio 3.19, p <0.001) were independent predictors of MACEs. Similar findings were observed when the SRI was entered in a separate model. In conclusion, even a mild degree of ICR is associated with a higher incidence of MACEs on long-term follow-up after CTO PCI.