To determine whether primary percutaneous coronary intervention (PPCI) is associated with adverse outcomes following coronary artery bypass graft (CABG) among patients with ST-elevation myocardial infarction (STEMI).

Patients presenting with acute STEMI who underwent CABG between September 2015 and November 2020 were included. Among 354 patients, 222 (62.7%) underwent PPCI prior to CABG (PPCI+CABG group) and were compared with the rest of the patients (CABG only group). The effects of PPCI on primary endpoints---including in-hospital mortality, length of stay (LOS), and bleeding events---were investigated using the stabilised inverse probability weighting method (S-IPW). Further, in-hospital mortality in various PPCI subgroups was analysed using univariable regression.

Patients with and without PPCI were comparable regarding their baseline and surgical characteristics, except that those without PPCI were more likely to have left-main disease (29.5% vs 16.2%, p-value=0.003). Among the PPCI+CABG group, 3.6% mortality and 55.9% bleeding events occurred, and the LOS was 7 [5–10] days. The respective figures for the CABG only group were 4.5%, 50.8%, and 7 [6–10.5] days. Primary percutaneous coronary intervention, as a whole, was not significantly associated with either morality (S-IPW odds ratio (S-IPW OR) 0.61; p=0.393), LOS logarithm (S-IPW β –0.050; p=0.403), or bleeding events (S-IPW OR 1.06; p=0.821). Nevertheless, the unadjusted mortality risk was significantly higher in complicated PPCIs compared with the CABG only group (OR 7.50, 95% CI 2.03–27.77); it was also higher among some other PPCI subgroups, albeit non-significantly.

This study found that PPCI did not confer additional risk regarding in-hospital mortality, LOS, or bleeding among patients with acute STEMI who underwent CABG. However, some PPCI subgroups, especially those with complicated PPCI, were at increased risk.