ILUMIEN I Published: OCT Can Affect PCI Strategy

Use of OCT both before and after PCI can have substantial impact on how operators treat patients with stable angina or ACS, according to a study published online August 4, 2015, ahead of print in the European Heart Journal.  

Findings from the ILUMIEN I trial were previously presented in May 2015 at the EuroPCR meeting in Paris, France.   

William Wijns, MD, PhD, of Cardiovascular Center Aalst (Aalst, Belgium), and colleagues enrolled 418 patients (mean age 64.6 years; 24.5% women) undergoing PCI at 35 international centers. Patients presented with:

• Stable angina (63%) 
• Unstable angina (22%) 
• NSTEMI (11%) 
• Silent ischemia (4%) 

The target vessel was the LAD in 59% of cases, the RCA in 22%, and the circumflex in 19%, with 90% of patients having a single lesion treated. At baseline, mean diameter stenosis was 73% on angiography and mean FFR value was 0.72. Per protocol, PCI was indicated when FFR values were ≤ 0.80.   

After the initial angiography, FFR was performed. Investigators were requested to describe the planned PCI strategy based on available angiographic data. OCT was then performed. Operators recorded any planned changes in strategy and performed PCI, which was followed by OCT and FFR. Operators were not given any specific recommendations on whether to intervene or not based on the post-PCI angiographic and/or OCT findings.   

Changes to Plans Both Before, After PCI

Pre-PCI OCT resulted in alterations to the treatment plan in 55% of patients. Additional unplanned stent implantation and postdilatation were performed in 40 cases until the PCI result was seen as satisfactory by angiographic standards, as determined by the operator. Pre-PCI OCT led to shorter stents than initially planned in 25% of lesions and longer stents in 43%. In addition, stent diameter decreased in 31% and increased in 8%. The total number of stents remained the same in 87% of cases, and the number of implanted stents per patient did not change.   

Post-PCI OCT not uncommonly revealed abnormal findings—eg, malapposition (14.5%), underexpansion (7.6%), and edge dissection (2.7%)—that led operators to decide on further optimization in 25% of patients. In 81%, additional postdilation was performed. However, a new stent was placed in 13% and both postdilation and a new stent were deemed necessary in 3%.    

FFR values after PCI differed between optimization groups (lower in cases with pre- and post-PCI changes based on OCT) but converged after post-PCI stent optimization using OCT.   

Device-oriented MACE (cardiac death, MI, and TLR) and patient-oriented MACE (all-cause death, MI, and any repeat revascularization), both in hospital and at 30 days, were rare overall. Importantly, rates of clinically significant periprocedural MI differed depending on whether procedural changes were made based on pre- and post-PCI OCT (table 1).  

“In-hospital findings of ILUMIEN I do raise the intriguing hypothesis that safety of PCI could be further improved by reducing the rates of periprocedural MI,” Dr. Wijns and colleagues write. “Severe stent underexpansion and malapposition are known to induce turbulences and pressure loss. Platelet aggregation and distal emboli may occur, especially with high residual platelet reactivity.

This hypothesis should inform the design of prospective, randomized trials aiming at establishing the clinical superiority of OCT-guided PCI vs sole angiographic guidance,” they say.

ILUMIEN III Coming   

One such trial, ILUMIEN III, is under way. In a telephone interview with TCTMD, Ziad A. Ali, MD, DPhil, of Columbia University Medical Center (New York, NY), said that this randomized controlled study, with a planned enrollment of 420 patients at 35 centers, will compare OCT, IVUS, and angiography with the goal of determining whether PCI changes applied under OCT guidance affect hard outcomes.

“One of the problems has been that there are no standards as to how you should stent according to intravascular imaging results,” noted Dr. Ali, who is the trial’s global primary investigator. “ILUMIEN III is a nice scientific progression from where we started [with ILUMIEN I] to a systematic methodology in ILUMIEN III that is testing how much we can improve overall outcomes with OCT.”  

According to Dr. Ali, use of OCT is no more burdensome for operators than IVUS, which he reported is used in 15% to 20% of all PCI procedures in the United States.

“As with anything, once it becomes a part of the workflow, it becomes less noticeable and less time consuming,” Dr. Ali said. “Personally, my OCT cases are no any longer than my non-OCT cases. But it’s providing me with information that I wouldn’t otherwise get from angiography.”

Clinical Justification Still Needed

In a telephone interview with TCTMD, William F. Fearon, MD, of Stanford University Medical Center (Stanford, CA), said the percentage of cases that were changed in ILUMIEN I is “eye opening and shows us what we may be missing by just evaluating the angiogram alone.”   

However, while OCT detects malapposition and dissection to a greater degree than does IVUS, Dr. Fearon said, it will be important eventually to show that the changes made with OCT are worth the added time and expense by demonstrating that they either facilitate PCI or improve outcomes.    

Dr. Ali agreed, noting that no studies to date have shown that treating acute stent malapposition changes outcomes. ILUMIEN III, he added, has “dedicated and defined criteria” to pinpoint whether any changes based on OCT findings are likely to alter flow.

 

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Source: 
Wijns W, Shite J, Jones MR, et al. Optical coherence tomography imaging during percutaneous coronary intervention impacts physician decision-making: ILUMIEN I study. Eur Heart J. 2015;Epub ahead of print. 

Disclosures:

• Dr. Wijns reports receiving research grants from Boston Scientific and Volcano. 
• Dr. Ali reports receiving grant support and consulting fees from St Jude Medical. 
• Dr. Fearon reports receiving research support from St Jude Medical. 

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