Non-culprit lesions detected during primary PCI: treat invasively or follow the guidelines?

Aims: Evidence regarding the optimal treatment of non-culprit lesions detected during primary PCI is lacking. Our aim was to investigate whether early invasive treatment improves left ventricular ejection fraction (EF) and prevents major adverse cardiac events (MACE). Methods and results: Of 121 patients with at least one non-culprit lesion, 80 were randomised to early FFR-guided PCI (invasive group), and 41 to medical treatment (conservative group). Primary endpoint was EF at six months, secondary endpoints included MACE. In the invasive group, early angiography was performed 7.5 days (5-20) after primary PCI. Forty percent of the non-culprit lesions did not show haemodynamic significance (FFR > 0.75). Subsequent PCI of at least one non-culprit lesion was performed in 52%, PCI without preceding FFR was performed in 8% and elective CABG was done in 4%. No in-hospital events occurred in the conservative group. After six months, EF was comparable (59 +/- 9% vs. 57 +/- 9%, p=0.362), and there was no difference in MACE between invasively and conservatively treated patients (21 vs. 22%, p=0.929). Conclusions: An invasive strategy towards non-culprit lesions does not lead to an increase in EF or a reduction in MACE. The functional stenosis severity of non-culprit lesions is frequently overestimated.