Using optical coherence tomography (OCT) to guide stent implantation during percutaneous coronary intervention (PCI) may be safer and lead to better outcomes for heart disease patients than angiography-guided PCI alone, the most commonly used method.
These are the findings from the largest clinical trial of its kind comparing the two methods for this procedure. The “ILUMIEN IV: OPTIMAL PCI” study results were presented on Sunday, August 27, in a Hot Line session at the European Society of Cardiology Congress (ESC 2023) in Amsterdam, Netherlands, and published in The New England Journal of Medicine.
Patients with coronary artery disease—plaque buildup inside the arteries that leads to chest pain, shortness of breath, and heart attack—often undergo PCI, a non-surgical procedure in which interventional cardiologists use a catheter to place stents in the blocked coronary arteries to restore blood flow. Interventional cardiologists most commonly use angiography to guide PCI, which involves a special dye (contrast material) and X-rays to see how blood flows through the heart arteries to highlight any blockages.
Angiography has limitations, making it difficult to determine the true artery size and the makeup of the plaque, and is suboptimal in identifying whether the stent is fully expanded post-PCI and other complications that affect the safety and effectiveness of the procedure. Intravascular ultrasound (IVUS) is another technique that provides a more accurate and specific picture of the coronary arteries. Even though studies have shown that IVUS-guided PCI is superior to angiography-guided PCI and reduces cardiovascular events, it is only used in roughly 15 to 20 percent of PCI cases in the United States, since images may be difficult to interpret.
An even newer technique is OCT, which uses light instead of sound to create images of the blockages. OCT images are much higher in resolution, more accurate, and more detailed compared to IVUS, and easier to interpret. However, as a newer technique, OCT is used in only 3 percent of PCI cases, partly because of a lack of study data—something this new trial aims to change.
The ILUMIEN IV: OPTIMAL PCI trial randomized 2,487 patients to OCT-guided PCI using a device manufactured by Abbott Vascular and angiography-guided PCI between May 2018 and December 2020. The study took place at 80 centers in 18 countries and patients did not know what type of guided procedure they received. Researchers evaluated the dimensions of the stented area post-PCI since re-narrowing of the stent over time can lead to repeat revascularization procedures.
Overall, patients in the OCT group had a substantially larger stent area compared to the angiography-guided group immediately after the procedure—an increase of .36mm2. OCT guidance also led to fewer procedural complications than angiography guidance. Researchers also looked at target lesion failure (TLF)—the combination of cardiac death, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization. Two years after the procedure, 88 patients in the OCT group had TLF compared to 99 in the angiography group, a difference that did not reach statistical significance.
The study went further and analyzed rates of stent thrombosis, one of the most severe complications of PCI. Within two years of PCI, six patients in the OCT group had stent thrombosis, compared to 17 in the angiography group, meaning that OCT reduced these instances by 65 percent. Additionally, 96 percent of patients who had a stent thrombosis in the trial died or had a subsequent myocardial infarction, emphasizing the importance of preventing these events.
This study was funded by Abbott Vascular. During the same hotline session at ESC 2023, Dr. Stone presented the results of an updated meta-analysis from the 20 trials of OCT-guided PCI and IVUS-guided PCI compared with angiography-guided-PCI, including ILUMIEN IV and one other new trial presented at the ESC. In total, 12,428 patients were enrolled in these studies, and results show that IVUS and OCT guidance reduced cardiac death by 46 percent, reduced target vessel myocardial infarction by 20 percent, and reduced target lesion revascularization by 29 percent, stent thrombosis by 52 percent, and overall target lesion failure by 31 percent compared with angiography guidance. The outcomes were similar for OCT-guided PCI and IVUS-guided PCI.
“These results emphasize the importance of physicians routinely using intravascular imaging with either OCT or IVUS to optimize stent outcomes and improve the long-term prognosis of their patients,” Dr. Stone said.