OCT has been shown to be noninferior to IVUS. OCT, with its superior resolution, can detect malapposition and major dissection that can be missed by IVUS. The ILUMIEN III trial randomized patients undergoing PCI to OCT, IVUS or angiographic guidance.

In terms of the primary endpoint of final median minimum stent area, OCT guidance was shown to be noninferior to IVUS. Minimum and mean stent expansion were significantly greater with OCT-guided PCI as compared to angiography-guided PCI, but were similar to IVUS-guided PCI. Procedural success was higher with OCT than with angiography.

OCT detected approximately 2.5 times more major dissections, 45% more major malposition & approximately 3 times more major plaque or thrombus protrusions than detected by IVUS.

OCT could be of most benefit in complex PCI cases. OCT-guided PCI using a specific reference segment external elastic lamina-based stent optimization strategy seems safe and results in similar minimum stent area to that of IVUS-guided PCI.

ILUMIEN IV trial has been initiated to evaluate long-term outcomes of patients who undergo stent implantation guided by OCT compared to angiography. The trial will enroll up to 3,650 patients with high-risk, complex disease at 125 centers in North America, Europe and Asia. It will determine if OCT-guided stent procedures result in larger vessel diameters, thus allowing increased blood flow and whether this will improve clinical outcomes for patients compared to stent procedures guided by angiography.