Studies Evaluate OCT and IVUS Guidance for PCI

August 27, 2023—The European Society of Cardiology (ESC) announced that findings from three studies of optical coherence tomography (OCT) for stent guidance in percutaneous coronary intervention (PCI) procedures were presented in a Hot Line session at the ESC Congress 2023 held August 25-28 in Amsterdam, the Netherlands.

The studies are:

• The ILUMIEN IV trial, which was presented by Ziad Ali, MD, found mixed efficacy of OCT in stent insertion in complex cases. OCT-guided PCI led to a larger minimum stent area but did not reduce the 2-year rate of target vessel failure compared with angiography-guided PCI. An additional finding was that stent thrombosis was significantly reduced with OCT-guided PCI.
• OCTOBER showed that OCT improved stent implantation outcomes in bifurcation lesions with reduced adverse cardiac events in data presented by Lene Nyhus Andreasen, PhD-student.
• In the OCTIVUS trial, principal investigator Professor Duk-Woo Park, MD, presented findings that concluded OCT was noninferior to intravascular ultrasound (IVUS) for stent guidance. This head-to-head comparison of OCT-guided and IVUS-guided PCI evaluated clinical outcomes in patients with a broad range of coronary artery lesions.

Also in the Hot Line session, Gregg Stone, MD, presented findings of a real-time updated network meta-analysis using the ILUMIEN IV and OCTOBER data integrated with findings from previous studies that showed intravascular imaging-guided PCI was associated with a lower rate of target lesion failure compared with angiography-guided PCI.

As summarized in the ESC press release, the ILUMIEN IV trial enrolled patients with medication-treated diabetes and/or complex lesions (defined as non–ST-segment elevation myocardial infarction (STEMI), late-presenting STEMI [> 24 hours], stent length ≥ 28 mm, severe calcification, two-stent bifurcation, in-stent restenosis, or chronic total occlusion) at 80 sites in 18 countries.

The investigators chose to include only complex patients and complex lesions because these patients were considered the most likely to gain the benefit of OCT guidance.

Patients were randomized (1:1) to OCT-guided PCI or angiography-guided PCI. Blinded OCT was performed after PCI in the angiography group to enable assessment of the first coprimary endpoint and other differences between the two treatment arms. Patients and post procedure research personnel were blinded to treatment assignment.

The coprimary endpoints were post-PCI minimum stent area assessed by OCT and the 2-year rate of target vessel failure, defined as a composite of cardiac death, target vessel myocardial infarction (MI), or ischemia-driven target vessel revascularization. Safety was also assessed.

The trial enrolled 2,487 patients with 1,233 receiving OCT-guided PCI and 1,254 receiving angiography-guided PCI. The mean age of participants was 65.6 years and 22.6% were women.

For efficacy, the minimum stent area achieved was larger in the OCT-guided group than in the angiography-guided group (5.72 ± 2.04 vs 5.36 ± 1.87 mm²; difference 0.36 mm²; 95% CI, 0.21 to 0.51; P < .001).

Target vessel failure within 2 years occurred in 88 OCT-guided patients and 99 angiography-guided patients (Kaplan-Meier estimated rates 7.4% vs. 8.2% respectively; hazard ratio [HR] 0.90; 95% CI, 0.67-1.19; P = .45).

Regarding safety, there were fewer angiographic complications with the OCT-guidance strategy.

In addition to the larger minimum stent area, OCT guidance resulted in fewer cases of major dissection, malapposition, tissue protrusion, and untreated reference segment disease. Stent thrombosis within 2 years occurred in six (0.5%) OCT-guided patients and in 17 (1.4%) angiography-guided patients (HR, 0.36; 95% CI, 0.14-0.91). There were fewer cardiac deaths and MIs in the OCT group, but these differences were not statistically significant, reported the ESC press release.

According to the ESC press release, OCTOBER was the first adequately powered clinical trial to examine whether routine use of OCT during PCI of complex bifurcation lesions improves clinical outcomes compared to standard practice with angiographic guidance and optional use of IVUS in left main bifurcations.

In the OCTOBER study, patients with complex bifurcation lesions requiring PCI were randomized (1:1) to OCT-guided PCI or angiography-guided PCI.

OCT-guided PCI was performed according to a detailed treatment protocol which included stepwise evaluation of (1) lesion preparation, (2) lesion length, (3) reference sizes, (4) lesion coverage, (5) stent expansion, (6) malapposition, (7) wire positions, and (8) ostial results. Investigators received training and core lab feedback on OCT-guided procedures throughout the trial.

In the angiography-guided group, the use of IVUS was allowed in patients requiring treatment of left main artery stenosis.

The OCTOBER trial included 1,201 patients from 38 heart centers in 13 countries in Europe. Of these, 600 patients were allocated to OCT-guided PCI and 601 patients were allocated to angiography-guided PCI. The average age of patients was 66 years, and women were 21% of patients in both groups.

In the OCTOBER study’s primary endpoint, major adverse cardiac events (defined as a composite of cardiac death, target lesion MI, and ischemia-driven target lesion revascularization) after 2 years occurred in 10.1% of patients in the OCT group and 14.1% of patients in the angiography group (Kaplan-Meier estimated HR, 0.70; 95% CI, 0.50-0.98; P = .035).

Secondary endpoints included all-cause mortality, cardiac death, target lesion MI, and target lesion revascularization. Differences in secondary clinical endpoints after 2 years did not reach statistical significance, but the trial was not powered for these endpoints. In the OCT group compared to the angiography group all-cause death was 2.4% versus 4.0% (HR, of 0.56; 95% CI, 0.28-1.10) and cardiac death was 1.4% versus 2.6% (HR, 0.53; 95% CI, 0.22-1.25).

In the OCT group compared to the angiography group, the incidence of target lesion MI, was 7.8% versus 8.5% (HR, 0.9; 95% CI, 0.6-1.34) the incidence of target lesion revascularization was 3.1% versus 5.0% (HR, 0.63; 95% CI, 0.35-1.15).

There were no apparent differences in procedural safety, but both the volume of contrast and the procedure time were increased with OCT-guided PCI compared with angiography-guided PCI, advised the ESC press release.

The ESC press release of the OCTIVUS trial advised that this investigator-initiated, prospective, multicenter, randomized, open-label pragmatic trial was conducted at nine sites in South Korea. It enrolled patients aged ≥ 19 years who were undergoing PCI with contemporary drug-eluting stents or drug-coated balloons (only for in-stent restenosis) for significant coronary artery lesions. As a pragmatic trial, the enrollment criteria were designed to capture a broad range of patients with various anatomical or clinical characteristics.

In OCTIVUS, a total of 2,008 patients were randomized (1:1) to undergo either OCT-guided or IVUS-guided PCI after diagnostic coronary angiography. The average age of patients in the study was 64.7 years and 21.6% were women. Overall, 33.4% of patients had diabetes, 76.6% presented with stable ischemic heart disease and 23.4% presented with an acute coronary syndrome.

The primary endpoint was a composite of death from cardiac causes, target vessel MI or ischemia-driven target vessel revascularization at 1 year, which was powered for noninferiority of the OCT group versus the IVUS group (noninferiority margin, 3.1 percentage points).

At 1 year, the primary endpoint occurred in 25 of 1,005 patients (2.5%) in the OCT-guided PCI group and in 31 of 1,003 patients (3.1%) in the IVUS-guided PCI group (risk difference, −0.6 percentage points; upper boundary of the one-sided 97.5% CI, 0.97; P < .001 for noninferiority).

In safety endpoints, the incidence of contrast-induced nephropathy was similar in the OCT and IVUS groups (1.4% vs 1.5%). The incidence of major procedural complications was lower in the OCT group (2.2% vs 3.7%; P = .048).

The amount of contrast used was higher in the OCT group (average, 238.3 vs 199.8 mL; P < .001), but the total PCI time was shorter in the OCT group (mean, 46.1 vs 48.9 minutes; P < .001), noted the ESC press release on the OCTIVUS trial.

In the meta-analysis presented by Dr. Stone, the investigators integrated the ILUMIEN IV and OCTOBER data with previous studies’ findings to examine the effects of intravascular imaging guidance versus angiography guidance.

As summarized in the ESC press release, the analysis compared (1) the overall effects of intravascular imaging (IVUS and OCT) in improving outcomes of PCI versus angiography, (2) IVUS versus angiography, (3) OCT versus angiography, and (4) IVUS versus OCT.

The analysis incorporated 20 randomized trials of intravascular imaging-guided PCI compared with angiography-guided PCI in 12,428 patients with chronic and acute coronary syndromes. Of those patients, 7,038 were randomly allocated to intravascular imaging guidance (including 3,120 patients randomized to IVUS guidance; 2,826 patients randomized to OCT guidance; and 1,092 patients randomized to IVUS or OCT guidance). The other 5,390 patients were randomly allocated to angiography guidance. Patients were followed for between 6 months and 5 years.

The primary endpoint was target lesion failure (defined as a composite of cardiac death, target vessel MI, or target lesion revascularization). Secondary endpoints included cardiac death, target vessel MI, target lesion revascularization, and stent thrombosis, as well as all-cause death, all MI, and target vessel revascularization.

Intravascular imaging (IVUS or OCT) guidance of PCI resulted in reductions in the primary composite outcome of target lesion failure by 31% compared with angiography guidance of PCI.

In secondary outcomes, intravascular imaging guidance of PCI resulted in reductions in cardiac death by 46%, target vessel MI by 20%, target lesion revascularization by 29%, and stent thrombosis by 52% compared with angiography guidance of PCI.

There were also statistically significant reductions in all-cause death, all myocardial infarction, and target vessel revascularization with intravascular imaging guidance of PCI. The outcomes were similar for OCT-guided PCI and IVUS-guided PCI when compared individually against angiography and when compared to each other.

Dr. Stone, the study’s Principal Investigator who is with the Icahn School of Medicine at Mount Sinai in New York, New York, commented in the ESC press release, “The results of this network meta-analysis emphasize the importance of physicians using intravascular imaging with either OCT or IVUS to optimize stent outcomes and improve the long-term prognosis of their patients.”