Original title: Residual SYNTAX score after PCI for triple vessel coronary artery disease: quantifying the adverse effect of incomplete revascularisation. Reference: Christopher J. Malkin et al. EuroIntervention 2013;8:1286-1295.

In the angioplasty branch of the SYNTAX study, complete revascularization was reached in 56.7% of the population. On the other hand, in the real world, around 40% of patients that present acute coronary syndrome has multi-vessel disease but only a third of theses receive complete revascularization. Given the significant number of patients with incomplete revascularization, it is important to determine how it affects prognosis and what an acceptable revascularization degree (if existent) is.

Complete or incomplete revascularization used to be a binary variable, but this study introduces the concept of residual SYNTAX score (rSYNTAX) that quantifies revascularization degree post PCI. A retrospective analysis was carried out of all patients with three vessels disease in one center between 2003 and 2008. It included both stable patients and those with acute coronary symptoms in an attempt to get the most complete revascularization possible in a procedure. The rSYNTAX was calculated by subtracting the basal score of each successfully treated lesion and the delta SYNTAX to the difference between the basal and the residual score.

240 patients with three vessels disease and a median basal SYNTAX of 29 (22-38) were included. A basal score >32 was significantly associated with diabetes, ventricular dysfunction, peripheral disease, surgical turndown and emergency presentation (all p<0.01). Complete revascularization (rSYNTAX =0) was achieved in 40% and median rSYNTAX was 3.5. At the end of follow up (2.6 years) only residual SYNTAX was a predictor of mortality, compared to basal SYNTAX or delta SYNTAX that after the adjustment did not come out as predictors.

Conclusion: 

Residual score SYNTAX resulted an independent predictor of mortality in non selected patients ongoing PCI for multi-vessel disease. Complete revascularization (residual SYNTAX =0) seems to be the goal in patients with multi-vessel disease as long as it can be reached safely..

Editorial Comment: 

It does not analyze the residual SYNTAX score from which the curves separate and the difference in mortality start to be significant. Analyzing a residual zero SYNTAX vs. non zero, as did this study, for practical reasons, is exactly the same as comparing complete revascularization vs. incomplete. There will certainly be some work on the SYNTAX concept to give us the number we have been searching for, a safe degree of incomplete revascularization. 

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