ILUMIEN IV Trial of OCT in Stent Implantation Initiates Enrollment

Charles Simonton, MD

Abbott has announced the launch and first patient enrollment of the largest randomized clinical trial to evaluate the use of optical coherence tomography (OCT) to guide stent implantation compared with the standard of care, X-ray guided angiography, in patients with high-risk, complex coronary artery disease.

Dubbed ILUMIEN IV, the trial will randomize a minimum of 2500 patients (target enrollment, 3650) 1:1 to either X-ray guided or OCT-guided implantation of a XIENCE stent. Ziad A. Ali, MD, the director of Intravascular Imaging and Physiology at Columbia University Medical Center's Center for Interventional Vascular Therapy and co-principal investigator of the study, said in a statement that “most of the world uses angiography for stent implantation using a 2-dimensional view of the coronary artery to assess a complex 3-dimensional structure. Physicians need new technology to help optimize percutaneous coronary intervention.”

“You do have to introduce another catheter, but OCT can take a 3-dimensional picture and give you almost a topographic map of the area” Charles Simonton, MD, the chief medical officer and divisional vice president of Medical Affairs for Abbott's vascular business, told MD Magazine. “It gives you the ability to see much more.”

The primary outcome of the trial is a composite of cardiac-related death, myocardial infarction, and restenosis after 2 years of follow-up. Secondary endpoints will be the individual outcomes that make up the primary composite, as well as post-procedure minimal stent area (MSA).

Previously, the ILUMIEN III trial of 450 patients revealed that OCT was comparable in MSA and stent expansion as intravascular ultrasound (IUVS)-guided PCI; that it resulted in significantly greater stent expansion than angiography-guided percutaneous coronary intervention—with greater rates of procedural success; and that it was superior to IVUS-guided PCI at detecting predictors of major adverse events, such as major stent malapposition and dissection.

The ILUMIEN IV trial’s focus on high-risk patients is in an effort to collect data on patients with complex, and both multiple or total blockages, which accounts for the increasing number of cases, according to Abbott.

“What a lot of people think is that if you have the extra precision of OCT, where you can get the stent size right, it would improve patient outcomes—less re-blockage, heart attack,” Simonton said. “This is a big high order sort of academic trial.”

"I'm confident this technology will have a positive impact on clinical practice around the world and we hope to provide evidence for leading medical organizations to update clinical guidelines for stent implantation based on the results of this study," Ali said in a statement.

In addition to the benefits in precision that OCT provides, the procedure also has benefits for the physicians utilizing it, as it is suggested that it reduces the amount of radiation that interventional cardiologists, patients, and operators have to be exposed to. The technology is light-based, rather than radiation based, and “it’s not hard to train people to do it,” Simonton said.

“You can use OCT to make decisions without having to do as many X-rays. You save the operator and patient from extra radiation, and there is less dye/contrast injection, which is bad for patients with kidney failure—a common occurrence with heart failure patients,” Simonton added.

Simonton told MD Magazine that Abbott plans to conduct a study to determine the differences in radiation exposure, by comparing laboratories that utilize OCT with those that do not. At the American College of Cardiology’s 67^th Annual Scientific Session and Expo, multiple poster presentations revealed up to a 6-fold increase in left-sided tumors for interventional cardiologists.

“Radiation is a big concern. We work in radiation all day,” Puneet Gandotra, MD, the director of the Cardiac Catheterization Lab at Southside Hospital, told MD Magazine. “Interventional cardiologists are at a high risk for having cataracts because of the radiation to the eyes. Interventional cardiologists are at a high risk for having tumors in the left side of their head because we work with the radiation that directly effects the left side of our heads.”