OCT-guided PCI as accurate as intravascular ultrasound, with comparable minimum stent areas

By Liz Meszaros, MDLinx
Published October 31, 2016

Key Takeaways

In patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI), optical coherence tomography (OCT) may offer improved guidance and safety, according to data from the ILLUMIEN III: OPTIMIZE PCI trial, which was published in the latest issue of The Lancet. Researchers found that when tested against intravascular ultrasound (IVUS)-guided PCI, OCT guidance provided similar minimum stent areas.  

“The trial shows that OCT-guided stent implantation provides equally large luminal dimensions as other techniques with enhanced accuracy and precision,” said study chairman, Gregg W. Stone, MD, director of Cardiovascular Research and Education at the Center for Interventional Vascular Therapy, NewYork-Presbyterian/Columbia University Irving Medical Center, and professor of medicine at Columbia University Medical Center, New York, NY. “Specifically, OCT allowed stenting to be performed with fewer dissections and malapposition, findings that have been associated with poor long-term results.”

Traditionally, angiography has been used for PCI, but angiograms do not accurately depict atherosclerotic details, and residual dissections, thrombus, and plaque protrusion often go undetected. IVUS is more precise in comparison, by allowing for cross-sectional imaging of the vessel walls via tomography. OCT is the newest imaging modality, which may provide even higher resolution images than IVUS.

Dr. Stone and colleagues conducted this randomized, controlled study to determine whether a new OCT-based stent sizing strategy would result in a minimum stent area similar to or superior to that achieved with IVUS guidance, and compared this OCT-based approach with angiography guidance alone.

They included 450 patients from 29 hospitals in 8 countries who were scheduled to undergo PCI, and aged 18 years or older. Inclusion criteria included the presence of one or more target lesions located in a native coronary artery, with a visually estimated reference vessel diameter of 2.25-3.50 mm, and a length of less than 40 mm. Researchers excluded any patient with left main or ostial right coronary artery stenosis, bypass graft stenoses, chronic total occlusions, planned 2-stent bifurcations, and in-stent restenosis.

They randomized subjects (1:1:1) stratified by site using an interactive, web-based system in block sizes of three, to OCT guidance (n=158), IVUS guidance (n=146), or angiography-guided (n=146) stent implantation. OCT-guided PCI was done with a specific protocol that established stent length, diameter, and expansion according to reference segment external elastic lamina measurement.

“We used a specific protocol of OCT which sized the coronary artery precisely, to see if it could provide advantages over angiography and be as good as or better than IVUS,” said principal investigator, Ziad A. Ali, MD, DPhil, associate director of translational medicine at the Center for Interventional Vascular Therapy, NewYork-Presbyterian/Columbia University Medical Center, and assistant professor of medicine and the Louis V. Gerstner Scholar at Columbia University College of Physicians and Surgeons and principal investigator of the trial.

All patients then underwent final OCT imaging, and researchers analyzed 15 final OCT acquisitions (140 OCT, 135 IVUS group, and 140 angiography) for the primary endpoint.

Drs. Stone, Ali, and colleagues found a final median minimum stent area was 5.79 mm2 with OCT guidance, 5.89 mm2 with IVUS guidance, and 5.49 mm2 with angiography guidance.

From their analysis, they concluded that OCT guidance was non-inferior to IVUS guidance (one-sided 97.5% lower CI −0.70 mm2; P=0.001), but not superior (P=0.42); neither was OCT guidance superior to angiography guidance (P=0.12). Procedural major adverse cardiovascular events were seen in 3% of OCT, 1% of IVUS, and 1% of angiography subjects (OCT vs IVUS: P=0.37; OCT vs angiography: P=0.37).

“The superior resolution of OCT identified more dissections, malapposition, and tissue protrusion compared with angiography or IVUS alone – while achieving improved stent expansion and procedural success when directly compared to angiography,” concluded Dr. Ali.

Dr. Stone added: “ILUMIEN III: OPTIMIZE PCI is an important step toward our ultimate goal of improving patient outcomes with imaging during stenting. These results have set the stage for a larger randomized trial, ILUMIEN IV, which is currently being planned to determine whether OCT-guidance results in superior clinical outcomes compared to angiography-guidance.”

This study was funded, in part, by St. Jude Medical.

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