IVUS Tops Angiography for Guiding DES Implantation in Long Lesions

ORLANDO, FL—Patients with long coronary lesions have better clinical outcomes 1 year after second-generation DES implantation when the procedure is guided by IVUS instead of angiography, the randomized IVUS-XPL trial shows. The benefit is attributed to a lower rate of ischemia-driven TLR.

“To our knowledge, the current study is the first demonstration of the clinical benefit of IVUS guidance in second-generation DES implantation in an adequately powered randomized clinical trial,” write Myeong-Ki Hong, MD, PhD, of Yonsei University (Seoul, South Korea), and colleagues. The findings were presented at the American Heart Association 2015 Scientific Sessions and published simultaneously online in the Journal of the American Medical Association.

Marco Costa, MD, PhD, of University Hospitals Case Medical Center (Cleveland, OH), who gave a commentary following Hong’s presentation, called the results “very impressive” but questioned whether the relatively low use of balloon postdilatation in the trial (76% and 57% in the IVUS and angiography groups, respectively) could have influenced the findings.

The trial “may actually impact our practice, but it certainly would need to be replicated [in the United States] because that’s not how we use balloon postdilatation,” Costa said.

For the trial, conducted at 20 Korean centers, the researchers enrolled 1,400 patients (mean age 64 years; 69% men) who had typical chest pain or evidence of myocardial ischemia and indications for everolimus-eluting stent implantation for diffuse long coronary lesions (stent length of at least 28 mm based on visual estimate). All patients received Xience Prime stents (Abbott Vascular) and dual antiplatelet therapy with aspirin and clopidogrel for at least 6 months.

Patients randomized to IVUS guidance had stent size and length selected by online IVUS measurements, with adjunct high-pressure dilation used according to physician discretion based on IVUS, which was allowed at any time during PCI but mandatory after the procedure.

In the angiography-guided arm, stent size and length were chosen by visual estimation, with adjunct high-pressure postdilation used if the procedure did not yield an optimal result, defined as residual diameter stenosis of less than 30% by visual estimation and absence of dissection.

The average stent length overall was 39.3 mm. During the procedure, patients in the IVUS arm more frequently received adjunct postdilation (76% vs 57%) and had a larger mean final balloon size (3.14 vs 3.04 mm; P < .001 for both). As a result, the patients who underwent an IVUS-guided procedure had a higher minimum lumen diameter (2.64 vs 2.56 mm; P < .001) and lower diameter stenosis (12.79% vs 13.74%; P = .04) on post-intervention quantitative coronary angiography.

The primary endpoint of the trial—12-month MACE (cardiac death, target lesion-related MI, or ischemia-driven TLR)—occurred less frequently in the IVUS-guided arm (2.9% vs 5.8%; log-rank P = 0.007) due to a reduction in ischemia-driven TLR.

Two patients in each group developed stent thrombosis (HR 1.00; 95% CI 0.14-7.10).

In the IVUS-guided arm, about half of patients (54%) met IVUS criteria for stent optimization, defined as a minimal lumen cross-sectional area greater than the lumen cross-sectional area at the distal reference segments. Compared with patients not meeting those criteria, those who did had a lower rate of the primary endpoint in a post hoc analysis (1.5% vs 4.6%; HR 0.31; 95% CI 0.11-0.86).

Costa said the 1.5% MACE rate at 1 year of follow-up is unprecedented and should be investigated further.

Results Consistent With Earlier, Smaller Trials

PCI of diffuse long coronary lesions vs shorter lesions is associated with higher rates of in-stent restenosis and stent thrombosis, according to the authors, who say that IVUS guidance may help improve outcomes.

During PCI, IVUS “may be a useful tool for providing information on preintervention lesion characteristics, including vulnerable plaques, lesion severity, length, and morphology; on postintervention optimal stent implantation for stent expansion, extension, and apposition; and on possible complications after stent implantation,” Hong et al write.

Although prior meta-analyses have shown that IVUS guidance is associated with reductions in MACE, stent thrombosis, and TLR, there have been no RCTs up to this point with adequate power to prove that using IVUS improves clinical outcomes, they say.

In the current trial, “this large number of patients with lesions longer than in previous randomized trials leads to a sufficiently powered study able to prove the clinical usefulness of guidance with IVUS for second-generation DES implantation,” they write. “The clinical benefit of IVUS-guided DES implantation may be attributed to the larger minimal lumen diameter followed by the more frequent adjunct postdilation with a large-sized balloon in the IVUS-guided group.”

They note that a larger minimal lumen diameter is believed to be factor in preventing restenosis after DES implantation.

In terms of limitations, the researchers acknowledge that the criteria for stent optimization used in the trial were arbitrarily defined.

Costa noted that the criteria are not standard in the United States. However, he said, “sometimes we’re making things too complicated for the operator, and maybe [those] simple criteria [are] actually better than the complex, multiple variable criteria that we use in the US.”
 

Source: 
Hong S-J, Kim B-K, Shin D-H, et al. Effect of intravascular ultrasound-guided vs angiography-guided everolimus-eluting stent implantation: the IVUS-XPL randomized clinical trial. JAMA. 2015;Epub ahead of print.

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