More Evidence for Superiority of IVUS Over Angiography in PCI

Batya Swift Yasgur MA, LSW

December 18, 2019

Intravascular ultrasound (IVUS)-guided stent implantation yielded significantly lower rates of major adverse cardiac events up to 5 years, compared with angiographic guidance, research suggests.

The results are from the Impact of IntraVascular UltraSound Guidance on the Outcomes of Xience Prime Stents in Long Lesions (IVUS-XPL) trial, which randomized patients with long coronary lesions to receive either IVUS or angiography-guided everolimus-eluting stent implantation prior to percutaneous coronary intervention (PCI). The original trial showed promising results in reducing the incidence of major adverse cardiac events after 1 year.

The current follow-up to 5 years shows that, compared with angiography-guided stent implantation, IVUS-guided stent implantation had a significantly lower rate of major adverse cardiac events, with clinical benefits seen both within 1 year and from 1 to 5 years after implantation.

"This is just one more piece of data showing that IVUS guidance should be done more often, but what's new is that the benefit is maintained out to 5 years, and the curves diverge — meaning that the event rate in angiography-guided implantation gets worse, compared with IVUS-guided implantation, from 1 to 5 years," study coauthor Gary Mintz, MD, senior medical advisor, Cardiovascular Research Foundation and codirector of Transcatheter Cardiovascular Therapeutics (TCT), told | Medscape Cardiology.

Results of the study were presented at TCT 2019 and simultaneously published online in JACC Cardiovascular Interventions.

No Bias

The IVUS-XPL trial involved 1400 patients with chest pain or myocardial ischemia who had long coronary lesions (implanted stent length, ≥28 mm). Patients were randomized 1:1 to receive either IVUS- or angiography-guided everolimus-eluting stent implantation (n = 700 for both groups) immediately after coronary angiography but before PCI.

The primary outcome measure of the original trial was the composite of major adverse cardiac events, including cardiac death, target lesion-related (TRL) myocardial infarction, and ischemia-driven TRL, at 1 year, analyzed by intention-to-treat.

"The same stent was used in all patients, so there was no bias in terms of what type of stent was used," Mintz noted.

The original trial showed that the IVUS group had a significantly lower rate of the composite of major adverse cardiac events at 1 year compared with the angiography-guided group (2.0% vs 0.8%), with the benefits primarily due to lower risk for TLR.

The current trial extended the follow-up period to 5 years in 1183 patients who had completed the original trial, with the same composite outcome measure as the previous trial.

There was no difference in total duration of dual-antiplatelet therapy between the IVUS- and the angiography-guided groups (median, 12 months [6 − 14] vs 12 months [6 − 15]; = .484).

Optimizing Stent Implantation

At 5 years, major adverse cardiac events in the IVUS- and angiography-guided groups occurred in 36 patients (5.6%) vs 70 patients (10.7%), respectively (hazard ratio [HR], 0.50; 95% CI = 0.34 − 0.75; = .001).

Cardiac death alone was notably lower in the IVUS-guided than in the angiography-guided stent group (6 patients [0.9%] vs 14 patients [2.2%], respectively; HR, 0.43; 95% CI, 0.17 − 1.12; = .074).

However, the difference between the two groups was driven primarily by a lower risk for ischemia-driven TLR in the IVUS group, compared with the angiography-guided group (31 [4.8%] vs 55 [8.4%]; HR, 0.54; 95% CI, 0.33 − 0.89; = .007).

Between 1 and 5 years (the first landmark analysis and the follow-up period of the current study), major adverse cardiac events occurred in 17 patients (2.8%) receiving IVUS-guidance and 31 patients (5.2%) receiving angiography guidance (HR, 0.53; 95% CI, 0.29 - 0.95; = .031).

Between year 1 and year 5, no statistically significant differences were found between patients who did not meet IVUS criteria, compared with those who met criteria for stent optimization.

When the researchers conducted a subgroup analysis (by sex, age, or presence of diabetes, hypertension, smoking, number of diseased vessels, reference vessel diameter, or clinical presentation), they found that the lower 5-year rate of major adverse cardiac events in the IVUS-guidance group was consistent across all subgroups.

"Just putting an IVUS catheter into a coronary artery does not accomplish a whole lot, but putting in and using the information to optimize stent implantation is what accomplishes the improved outcome," Mintz commented.

"Suboptimal" Use

Commenting on the study for | Medscape Cardiology, Islam Elgendy, MD, research fellow in medicine, Massachusetts General Hospital and Harvard Medical School, Boston, said that, "despite being the largest randomized trial on the topic, this report is the first randomized trial that reports on the outcomes of IVUS guidance at 5 years, and a significant proportion of the patients completed the 5-year follow-up."

The trial "adds to the body of literature supporting routine use of IVUS guidance for optimization of PCI," said Elgendy, who was not involved with the study.

Elgendy noted that in this trial, "IVUS use was mandated only post-PCI, suggesting that not just using IVUS is important, but actually interpreting the findings and perhaps routing PCI use to carefully assess the lesion for the need of plaque modification, is important."

He called the low use of IVUS for PCI guidance "suboptimal among operators," adding that the "reasons for this low usage are not understood, since studies have shown that the use of IVUS is safe."

Moreover, an "abundance of studies support the benefit of IVUS guidance," he said, so the "suboptimal" use is not related to lack of data, and IVUS use is more cost-effective, especially in patients with comorbid conditions."

Mintz agreed. "IVUS has been around for almost 30 years, the first hint that IVUS improves stent implantation has been around for at least 20 years, and there are now many randomized controlled trials and meta-analyses demonstrating superiority of IVUS over angiography-guided implantation," he said.

"IVUS guidance should be done much more often," Mintz emphasized.

This work was supported by grants from the Korea Health Technology Research and Development Project through the Korea Health Industry Development Institute, funded by the Ministry of Health & Welfare, Republic of Korea; the Bio & Medical Technology Development Program of the National Research Foundation funded by the Korean government; and the Cardiovascular Research Center, Seoul, Korea. Mintz is a consultant to Boston Scientific, Philips/Volcano, and Terumo. The other authors and Elgendy report no relevant financial relationships.

JACC Cardiovasc Interv. Published online September 29, 2019. Abstract

Transcatheter Cardiovascular Therapeutics (TCT) 2019: Late-breaking trials 4. Presented September 29, 2019.

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