Background Factors affecting prognosis after primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) include age at presentation, the presence of diabetes mellitus, left ventricular function and/or cardiogenic shock. Although the debate continues over a strategy of complete revascularisation (immediate or staged) vs culprit-only, little is known about the impact of the extent of coronary disease at presentation on prognosis after PPCI. The SYNTAX score, designed to stratify outcomes in multivessel PCI and CABG, has been validated in unselected populations undergoing elective PCI; to date, no studies have assessed its utility in PPCI.
Methods Consecutive patients attending a single UK tertiary centre for PPCI between September 2008 and June 2010 (n=695) were included. SYNTAX scoring was performed by a single trained operator blinded to patient details and outcome. Scoring was validated by analysis of 3 separate cohorts by 2 other experienced operators. Patients were split into 3 subgroups as in the SYNTAX trial (score ≤22 (low, L), 22.5–32 (intermediate, IM) and ≥32.5 (high, H)), and patient data and outcome measures obtained by interrogation of local and national databases.
Results 671 of 695 patients were included in the analysis with 24 being excluded owing to inability to score (previous CABG, images unavailable). The ability to allocate a SYNTAX tertile was reproducible between observers (r=0.94). Median scores in the 3 groups were: L 14, IM 26, H 36 (Abstract 43 figure 1A). Although there was no correlation between SYNTAX score and patient sex or diabetic status, there was a linear relationship with patient age (r2=0.03; p<0.0001). 1-year absolute survival (Abstract 43 figure 1B) followed SYNTAX score groups: L 94.7%, IM 88.7%, H 82.1% (p=0.0002). Similar results were obtained for freedom from death or unplanned revascularisation (p<0.0001) and death or any revascularisation (p<0.0001).
Conclusions The SYNTAX score, when applied to an unselected population of patients undergoing PPCI for STEMI, provides important prognostic information regarding 1-year survival from death and revascularisation. These findings may provide supporting evidence towards routine complete revascularisation of obstructive coronary artery disease after PPCI.