Intravascular Ultrasound-Guided Versus Angiography-Guided PCI in Acute Coronary Syndromes (IVUS-ACS)

The IVUS-ACS trial randomized 3,505 patients presenting with acute coronary syndrome to intravascular ultrasound-guided versus angiography-guided percutaneous coronary intervention — asking whether the imaging benefit established for stable, complex lesions extends to the emergent setting.

IVUS-guided PCI reduced the composite of cardiac death, target-vessel MI, or ischemia-driven revascularization from 7.3 percent to 4.0 percent at one year — a 45 percent relative risk reduction (HR 0.55, p<0.0001). The benefit was consistent across ACS presentations including STEMI, NSTEMI, and unstable angina.

The finding is significant because ACS lesions are particularly challenging: they typically involve plaque rupture, superimposed thrombus, and hazardous coronary segments with ambiguous anatomy on angiography. The additional anatomical information from IVUS — stent expansion, landing zone characterization, edge dissection detection — is directly actionable in these high-stakes cases.

We rate the evidence strong. A large, well-powered contemporary RCT establishing IVUS-guided PCI as superior to angiography guidance in ACS — expanding the indication for intracoronary imaging from elective complex procedures to emergent intervention.