Residual SYNTAX score after PCI for triple vessel coronary artery disease: quantifying the adverse effect of incomplete revascularisation

AIMS: There is some evidence to suggest that incompleteness of coronary artery revascularisation after PCI is associated with inferior outcomes. The SYNTAX score was developed as a tool to quantify the extent of coronary artery disease in the SYNTAX study. We aimed to use this score to quantify the completeness of revascularisation after PCI (the "residual SYNTAX score") and to determine its impact upon mortality. METHODS AND RESULTS: We studied 240 consecutive patients with native three-vessel disease who underwent PCI between 2003 and 2008. SYNTAX scores prior to, and after, PCI were calculated, the difference (ΔSYNTAX) being a measure of the relative completeness of revascularisation. Median follow-up was 2.6 (1.2-3.2) years; 21% of patients were surgical turndowns, and 38% were non-elective. A residual (rSYNTAX) score of zero (full revascularisation) was achieved in 40% and median rSYNTAX was 3.5 (0-10.9). At final follow-up reduced mortality was found in patients with rSYNTAX 0 vs. others (2.5 vs. 12%, respectively, p=0.003) and for those with rSYNTAX<median vs.>median (3 vs. 11%, p=0.003). rSYNTAX was an independent predictor of mortality in a multivariate analysis, whereas baseline SYNTAX score was not. CONCLUSIONS: The residual SYNTAX score is a useful method to quantify incomplete revascularisation in patients undergoing PCI for 3VD. Complete revascularisation (rSYNTAX=0) is achieved in only a minority and, for them, the mortality rate is low.