Intravascular imaging for PCI beneficial in several studies, meta-analysis
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Key takeaways:
- Intravascular imaging-guided PCI was tied to better vessel-related and clinical outcomes compared with angiography-guided PCI.
- OCT and IVUS were equally effective for clinical outcomes.
The use of intravascular imaging — OCT or IVUS — during PCI appears to reduce complications and produce overall better clinical outcomes than using angiography guidance, according to three studies and a meta-analysis.
At the European Society of Cardiology Congress, researchers presented results of ILUMIEN IV, in which for patients with various complex characteristics, OCT-guided PCI was associated with larger minimum stent area than angiography-guided PCI and reduced risk for stent thrombosis, but target vessel failure did not differ between the groups; OCTOBER, in which for patients with complex bifurcation lesions, OCT-guided PCI reduced MACE compared with angiography-guided PCI; OCTIVUS, in which for patients with obstructive CAD, OCT was noninferior to IVUS for TVF; and a network meta-analysis of intravascular imaging compared with angiography, in which use of OCT or IVUS during PCI was associated with significant reductions in various clinical outcomes compared with angiography-guided PCI, improving survival.
Image: Adobe Stock
“I am not recommending that intravascular imaging be used in every single case, but I do think it should be used in the majority of patients,” Gregg W. Stone, MD, director of academic affairs for the Mount Sinai Health System and professor of medicine (cardiology), and population health science and policy at the Icahn School of Medicine at Mount Sinai, who presented the meta-analysis and chaired the ILUMIEN IV study, said during a press conference.
Rates of intravascular imaging use vary around the world, from 5% in Europe to 20% in the United States to more than 95% in Japan, Stone said.
ILUMIEN IV
For ILUMIEN IV, which was simultaneously published in The New England Journal of Medicine, the researchers randomly assigned 2,487 patients with diabetes or complex coronary artery lesions (mean age, 66 years; 77% men) to OCT-guided PCI or angiography-guided PCI.
The primary efficacy endpoint of minimum stent area after PCI was 5.72 mm2 in the OCT group and 5.36 mm2 in the angiography group (mean difference, 0.36 mm2; 95% CI, 0.21-0.51; P < .001), according to the researchers.
The primary clinical endpoint of TVF, defined as cardiac death, target vessel MI or ischemia-driven target vessel revascularization, at 2 years occurred in 7.4% of the OCT group and 8.2% of the angiography group (HR = 0.9; 95% CI, 0.67-1.19; P = .45), Ziad A. Ali, MD, DPhil, director of the DeMatteis Cardiovascular Institute at St. Francis Hospital and Heart Center in New York, and colleagues found.
The rate of definite or probable stent thrombosis was 0.5% in the OCT group and 1.4% in the angiography group (HR = 0.36; 95% CI, 0.14-0.91; P = .02). The researchers found 96% of patients with stent thrombosis subsequently died or had an MI.
Ali told Healio that the COVID-19 pandemic likely played a role in the results, as ischemia-driven target vessel revascularization rates dropped during the pandemic but the other events did not.
“Our analysis showed very clearly that prior to COVID, with patients who had at least 1 year follow-up, our hazard ratio of 0.7 was exactly where we anticipated when we powered the study,” he told Healio. “In addition, the hazard ratios for every component of the endpoints favored OCT except for target lesion revascularization. Cardiac death and stent thrombosis … continued to accrue because they cannot be changed by choice. These are some of the interesting nuances that we are putting together.”
OCTOBER
For OCTOBER, simultaneously published in NEJM, researchers randomly assigned 1,201 patients (mean age, 66 years; 21% women) indicated for PCI who had a complex bifurcation lesion to OCT-guided PCI or angiography-guided PCI.
At 2 years, the primary endpoint of MACE, defined as cardiac death, target lesion MI or ischemia-driven target lesion revascularization, occurred in 10.1% of the OCT group and 14.1% of the angiography group (HR = 0.7; 95% CI, 0.5-0.98; P = .035), according to the researchers.
Procedure-related complications occurred in 6.8% of the OCT group and 5.7% of the angiography group.
“Multiple studies have shown that OCT allows for optimization of bifurcation PCI, and our results confirm that such optimization may improve the patient’s prognosis,” Niels R. Holm, MD, from the department of cardiology at Aarhus University Hospital in Denmark, said during the press conference. “The OCTOBER trial results indicate that implementing routine OCT guiding for complicated bifurcation PCI may lead to improved clinical outcomes for a group of patients with increased risk of major cardiac events after PCI.”
OCTIVUS
The OCTIVIUS trial, simultaneously published in Circulation, compared OCT-guided PCI with IVUS-guided PCI in 2,000 patients with obstructive CAD indicated for PCI.
The primary endpoint of TVF, defined as cardiac death, target vessel MI or ischemia-driven TVR at 1 year, occurred in 2.5% of the OCT group and 3.1% of the IVUS group (HR = 0.8; 95% CI, 0.47-1.36; P for noninferiority < .001), the researchers found. There were no differences between the groups in any secondary outcomes.
“The primary results of OCTIVUS provide valuable insights into the comparative effectiveness of OCT-guided and IVUS-guided PCI,” Duk-Woo Park, MD, PhD, interventional cardiologist at Asan Medical Center, University of Ulsan College of Medicine in Seoul, South Korea, said during the press conference. “Both OCT and IVUS can be used safely and effectively in the vast majority of PCI procedures, demonstrating comparable acute and long-term outcomes.”
Meta-analysis
The network meta-analysis presented by Stone covered 12,428 patients from 20 trials: nine comparing IVUS vs. angiography, six comparing OCT vs. angiography, two comparing OCT vs. IVUS vs. angiography, two comparing OCT vs. IVUS and one comparing OCT or IVUS vs. angiography. It included ILUMIEN IV and OCTOBER but not OCTIVUS.
In 18 trials that compared intravascular imaging (OCT or IVUS)-guided PCI to angiography-guided PCI, imaging guidance reduced TLF by 31% (network estimate, 0.69; 95% CI, 0.61-0.78), and also reduced cardiac death, target vessel MI, TLR, stent thrombosis, all-cause mortality, all MI and TVR, Stone said during the press conference.
In four trials that directly compared OCT-guided PCI with IVUS-guided PCI, there were no significant differences in any outcomes, he said, noting that when the OCTIVUS results are added, it will push the numbers even more toward neutrality.
Cost-effectiveness analyses have not yet been performed, but the data suggest that intravascular imaging should be used in most patients and that work should be done to remove barriers to use, Stone said.
“This study has for the first time shown a reduction in all-cause mortality and all-MI with intravascular imaging. These findings should impact the guidelines, and if intravascular imaging is provided a class I recommendation in the guidelines, that will make a difference in imaging adoption. We but we also need to work on removing the impediments to widespread use of intravascular imaging guidance for most patients with PCI, and that requires focusing on reimbursement and on training issues,” he said. “We have to train our attendings better and the attendings have to train the fellows better. Intravascular imaging just needs to become a standard part of the PCI procedure.”
Ali told Healio that “The guidelines committees are finally going to be put on the spot. How much more evidence do you need before you make [intravascular imaging] a class Ia [recommendation]? I hope the totality of the data and the contribution of ILUMIEN IV push the field forward to do safer procedures for patients.”
References:
- Andreasen LN, et al. Hot line 4. Presented at: European Society of Cardiology Congress; Aug. 25-28, 2023; Amsterdam (hybrid meeting).
- Park DW, et al. Hot line 4. Presented at: European Society of Cardiology Congress; Aug. 25-28, 2023; Amsterdam (hybrid meeting).
- Stone GW, et al. Hot line 4. Presented at: European Society of Cardiology Congress; Aug. 25-28, 2023; Amsterdam (hybrid meeting).
- Ali ZA, et al. N Engl J Med. 2023;doi:10.1056/NEJMoa2305861.
- Holm NR, et al. N Engl J Med. 2023;doi:10.1056/NEJMoa2307770.
- Kang DY, et al. Circulation. 2023;doi:10.1161/CIRCULATIONAHA.123.066429.
Perspective
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PCI is being offered to more complex and difficult patients. Enhancing and optimizing our acute result should have an important impact on the long-term outcomes and the durability of the results, especially in terms of restenosis, recurrence or TVF.
Over the years, we have learned that intravascular imaging, particularly IVUS, has improved outcomes, especially as related to improving the stent area at the end of the procedure. This has been reflected in several meta-analyses, and U.S. and European clinical guidelines have supported the use of IVUS as a IIa recommendation.
There is more evidence for IVUS because it has been around longer than OCT. There have been interesting, smaller-scale OCT studies done to date, and ILUMIEN IV is now the largest study of OCT vs. angiography. There has been a lot of talk about how with OCT, you see better, you can figure out if there are issues with stent expansion, strut coverage, etc, and maybe it can help us do better in terms of improving clinical outcomes.
ILUMIEN IV, based on the premise established in ILUMIEN III that OCT would improve minimal stent area, showed OCT improved complications such malappositions and dissections. But in terms of clinical outcomes (TVF), it was a negative study. Improvement of those complications did not correlate with better outcomes at 2 years, except for an important endpoint of stent thrombosis which was reduced significantly with OCT and this is clinically plausible and important. Event rates were lower than expected, especially in the angio-guided arm. Furthermore, the kinds of patients in the study were perhaps not as complex as might have been imagined, although the protocol was focused on complex PCI.
However, the OCTOBER trial showed that OCT improved and enhanced outcomes in patients with bifurcation lesions, where the stakes are higher, the complication rate is higher and the evaluation of stent expansion is much more important.
The OCTIVUS study showed no difference between OCT and IVUS in clinical outcomes. So if IVUS and OCT are the same, why didn’t OCT translate into improvement of TVF? It remains to be seen why ILUMIEN IV was negative. But we cannot take away that we have enough data to show that OCT improves clinical outcomes, even with the meta-analysis that was done. That showed that intravascular imaging including IVUS and OCT improved outcomes, but it is hard to say anything about OCT by itself, especially in all-comers, except that in 1,200 patients with complex lesions from OCTOBER, there was a statistically significant benefit with OCT.
The totality of the data, even before this meeting, shows that imaging does enhance the acute results. Especially if the patient has a complex lesion morphology such as bifurcation lesions or left main artery lesions, it is best to perform imaging to put your best foot forward up front. That will continue to be a theme: There should be more imaging than what we currently have, and I am convinced that we will continue to show that imaging improved the outcomes of PCI. But I do not think that at this time, we have evidence that every single PCI should have imaging. We do not have the kind of data to support that at the moment, but I am convinced that we will get there.
We have to congratulate the investigators for working on how to better understand the impact of imaging on outcomes in PCI. I am proud of how the field of interventional cardiology tries to always use clinical evidence and data to enhance what we are trying to do for our patients.
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Ali ZA, et al. Hot line 4. Presented at: European Society of Cardiology Congress; Aug. 25-28, 2023; Amsterdam (hybrid meeting).
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