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First Randomized Control Trial to Determine the Role of OCT vs. Angiography

By Susan Thomas

With over 160 patients enrolled less than a year after study initiation, St. Francis Hospital – The Heart Center is the top enrolling site globally for ILUMIEN IV among 125 centers. The trial seeks to understand the clinical importance of Optical Coherence Tomography (OCT) to validate and surpass angiographic evidence for stent placement and whether they help improve long term clinical outcomes. OCT is a light-guided imaging technique which helps distinguish between the different blockages/lesions found in coronary arteries (calcium, lipid, thrombus, and fibrotic plaque). With the help of an easy to interpret 3-D images, OCT helps measure the length of the lesion and the lumen length to appropriately size stents and plan the best lesion preparation.

Patients are enrolled in the study and randomized—randomly assigned—to one of two groups: OCT guided PCI or angio-guided PCI.

OCT Guided PCI vs. Angiography Guided PCI  

Angiographic guided PCI meets the Standard of Care protocol practiced by interventional cardiologists. Stent sizing and intervention is based off of angiography. Following the completion of the intervention, a “blinded OCT-run” – an OCT image run done but not seen by the physician—is completed. This will be analyzed to determine if intravascular imaging through OCT produces superior results compared to angiography.  



In an OCT-guided PCI, the procedure starts with pre-intervention OCT imaging of the lesion. This is done prior to stenting to determine treatment plan and precise stent sizing. OCT is repeated to “optimize” after stenting to determine if the stent(s) is well expanded (> 90%) using a specified lumen dimension cutoffs.

Dr.s Richard A. Shlofmitz, Allen Jeremias, and Andrew Berke have been the investigators for this ongoing trial at St. Francis Hospital. We had a chance to sit with a few of the cardiologists for the study and asked them a few questions:


What are the implications of ILUMIEN IV on current PCI practices? 

Jeremias: “We believe that not using intravascular imaging to optimize stent implantation leads to sub-optimal procedural results, potentially impacting long-term outcomes for patients. By using OCT with the application of the ILUMIEN IV algorithm, we can be sure that the stent is optimally implanted and hopefully, will lead to better outcomes. 

Shlofmitz: “Angiography has been done since the 1960’s and has been the gold standard for assessing coronary anatomy. The problem with angiography is that it’s a 2D luminogram that doesn’t accurately represent what’s going on in the arteries. Imaging with IVUS and OCT changes what we interpret with an angiogram. The problem that we see with imaging is that it actually helps improve accuracy of what’s happening in the coronary arteries and improves outcomes and decreases complications. The problem is doctors have not embraced these technologies on a daily basis. Anywhere between 3-10% of cases worldwide use imaging and the rest of the cases are using technology from the 60s. It’s like comparing a rotary phone to an iPhone 10, except it’s more important in coronary arteries. 

Ilumien IV is trying to show that angiography is, very clearly, inferior to imaging with OCT and OCT gives better outcomes, better results, better lumen, decreased restenosis and decreased morbidity. Simply opening an imaging catheter doesn’t ensure better results. You need to follow the protocol with ILUMIEN IV. We’re optimizing angioplasty and not just imaging and looking, and looking at the angiogram to decide what we’re doing. The algorithm helps assess morphology to help pretreat to get the best results, and assessing your final results to make sure there’s no edge dissection, 90% luminal gain and well apposed stents.” 

What have you learned from being a part of the ILUMIEN IV trial that you would like to share with others? 

Jeremias: “Using intravascular imaging on routine basis completely changes ones practice and illustrates vividly how inadequate coronary angiography is for angiography guidance. It is disheartening to see that still today vast majority of the procedures are guided by angio only, potentially leading to suboptimal stenting. Optimization through imaging provides a new algorithm for future PCIs.” 

Shlofmitz: “ILUMIEN IV isn’t just a trial to prove imaging is better than angiography but a trial to show optimization of imaging. I’ve been learning how inadequate angiography alone is for stenting. When I used to stent years prior, I would look at an angiogram and stent based on what I saw on the screen. If the angio looked good, I pat myself on the back and go home. Now, I’m making sure I take the extra step to optimize to get better results by covering the entire abnormal area using normal to normal tissues, which is not seen on angio. For patient ILUMIEN IV will get precision angioplasty like they never had before, with the best possible results, which will become a routine procedure/standards.”