With respect to prevention of important clinical events, including cardiac death, percutaneous coronary intervention (PCI) under optical coherence tomography (OCT) guidance performs similarly to PCI guided by intravascular ultrasound (IVUS), a pair of new studies suggest.
In one of the studies, a randomized comparison of the two imaging catheter technologies in conjunction with PCI, OCT was found noninferior to IVUS with respect to the trial's primary composite clinical endpoint.
The other study, a network meta-analysis of randomized trials, compared standard angiography, OCT, and IVUS for their relative success at guiding PCI. It too found OCT and IVUS to be comparable. But its more clinically important message, the researchers and expert observers agree, was that both forms of intravascular imaging (IVI) are superior to guidance by standard angiography alone.
"Both OCT and IVUS can be used safely and effectively in the vast majority of procedures, as they are associated with comparable acute and long-term outcomes," principal investigator Duk-Woo Park, MD, PhD, said when presenting the OCTIVUS trial August 27 in Amsterdam, the Netherlands, at the European Society of Cardiology (ESC) Congress 2023. Park is also senior author on the study's same-day publication in Circulation.
The noninferiority comparison was conducted on the background of growing evidence that both imaging modalities are superior to angiography alone, the latter always the standard in practice for assessing coronary disease severity and choosing stent targets, observed Park, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
Low Event Rates Limit Conclusions
In OCTIVUS, 2008 patients (mean age, 65 years) slated for PCI, of significant, often complex coronary artery lesions, were randomized to have their procedures guided by either OCT (1005 patients) or IVUS (1003 patients).
About 22% were women, one-third had diabetes, and 76.6% and 23.4% had presented with stable coronary disease or an acute coronary syndrome, respectively. Patients presenting with acute ST-segment elevation myocardial infarction (MI), however, had been excluded from the study.
The primary endpoint (cardiac death, target-vessel-related MI, or target-vessel revascularization) at 1 year was met by 2.5% in the OCT group and 3.1% in the IVUS group (P < .001 for OCT noninferiority).
Major procedural complications were significantly less frequent with OCT (2.2% vs 3.7% for the IVUS group; P = .047), and the incidence of contrast-induced nephropathy was similar in both groups (1.4% and 1.5%, respectively).
Outcomes at 2 years were similar to the 1-year results, Park noted. However, he warned, event rates in both arms were unexpectedly low, which limited statistical power to discriminate the imaging technologies for outcomes. Still, the comparable acute and long-term outcomes suggest that "both can be used safely and effectively in the majority of procedures."
Are Guideline Changes Called For?
Guidelines in the United States and Europe currently give a Class IIa ("should be considered") recommendation supporting IVUS or OCT over angiography alone in selected cases, such as patients with complex lesions.
But the meta-analysis finding superiority of IVI over angiography alone across different types of coronary lesions, presented at the ESC sessions back to back with OCTIVUS, was said to support a recommendation upgrade to Class I ("is indicated").
As presented by Gregg Stone, MD, Mount Sinai Heart Health System, New York City, the network meta-analysis included 20 trials conducted from 2010 to 2023 encompassing 12,428 patients.
They included nine trials comparing IVUS with angiography only, six comparing OCT with angiography only, two comparing OCT vs IVUS vs angiography only, two comparing OCT with IVUS, and one comparing either OCT or IVUS with angiography only.
Two of the six OCT vs angiography-only trials in the network meta-analysis, ILUMIEN-4 and OCTOBER, were presented at ESC 2023 during the same August 27 session and were featured in a separate story from the theheart.org | Medscape Cardiology, along with further coverage of the meta-analysis. Those two trials were published the same day in the New England Journal of Medicine.
In the meta-analysis, and consistent with OCTIVUS, clinical outcomes were similar after OCT-guided and IVUS-guided procedures, Stone said. However, either form of IVI-guided PCI was followed by greatly reduced risk for major events compared with PCI with angiography only.
Overall, target-lesion failure (a composite of cardiac death, target-vessel MI, and target-lesion revascularization) was reduced by 31% when IVI-guided techniques were used instead of standard angiography. The benefit "was driven by 46%, 20%, and 29% reductions in cardiac death, target-lesion MI, and target-lesion revascularization, respectively," Stone said.
There was also a 52% reduction with IVI-guided PCI relative to angiography for the endpoint of stent thrombosis, and a 25% drop in all-cause mortality.
This "real-time" network meta-analysis, which was prompted by a collaboration of ILUMIEN-4 and OCTOBER investigators, provides the basis for a change in guidelines, said the study's ESC-invited discussant, Davide Capodanno, MD, PhD, University of Catania, Italy.
Evidence May Now Support a Class I Recommendation
The current evidence supporting OCT compared with IVUS is "less persuasive" due to fewer large comparisons, Capodanno said. But there is no longer any doubt that IVUS-guided PCI reduces risk for cardiac events relative to angiography. "This foundation supports the elevation of IVUS to a Class I [level of evidence A] recommendation, at least in cases involving complex lesions."
Capodanno, who did not discount OCT as a viable IVUS alternative, said that the two modalities "should be seen as complementary rather than mutually exclusive." He is awaiting more data, he said, on whether OCT or IVUS may be preferable in specific circumstances. But he singled out IVUS as deserving an immediate upgrade to standard-of-care status.
"I definitely would agree, especially now that we've seen a reduction in all-cause mortality" in the meta-analysis, Stone said. He also used the term "standard of care" to describe what should be the role of IVUS over angiography, "if not in all patients, then in most patients."
Deepak L. Bhatt, MD, director of Mount Sinai Heart, Icahn School of Medicine, New York City, moderator of the ESC session featuring the IVI studies, expanded on Stone's take on IVI-guided PCI. Reductions in all-cause mortality are in general rare and persuasive, he observed. Therefore, when any intervention provides an all-cause mortality benefit, "it generally means that you ought to do that thing." Bhatt added that "we will see" how guidelines respond to these data.
The investigator-initiated OCTIVUS trial was supported by the Cardiovascular Research Foundation, Abbott Vascular, and Medtronic. Park reports financial relationships with Abbott Vascular, Medtronic, Daiichi-Sanyo, Daewoong Pharma, and Chong Kun Dang Pharma. Stone discloses receiving research contracts from Abbott, Abiomed, BioVentrix, Cardiovascular Systems, Phillips, Biosense Webster, Shockwave, Vascular Dynamics, Pulnovo, and V-wave; consulting for, receiving royalties from, or being employed by or holding equity interest in Abbott, Daiichi-Sankyo, Ablative Solutions, Robocath, Miracor, Vectorious, Valfix, TherOx, HeartFlow, Neovasc, Ancora, Elucid Bio, Occlutech, Impulse Dynamics, Adona Medical, Millennia Biopharma, Oxitope, Cardiac Success, HighLife, Cagent, Applied Therapeutics, Biostar family of funds, SpectraWAVE, Orchestra Biomed, Aria, and Xenter; and receiving honoraria for speaking from Medtronic, Abiomed, Amgen, and Boehringer Ingelheim. Capodanno reports no potential conflicts of interest. Bhatt discloses a relationship with Medscape Cardiology; his other disclosures can be found at mountsinai.org.
Circulation. 2023. Published online August 27. Full Text
European Society of Cardiology (ESC) Congress 2023, Hot Line 4, presented August 27.
Lead Image: Pitchayanan Kongkaew/Dreamstime
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Cite this: Parity for OCT, IVUS in Intravascular Imaging-Guided PCI: OCTIVUS - Medscape - Sep 12, 2023.