麻豆传媒

To guide implantation of newer-generation drug-eluting stents (DES) in complex lesions, intravascular ultrasound (IVUS) beat angiography for reduced rates of subsequent MI, according to a meta-analysis.

One year after stenting, major adverse cardiovascular events -- the composite of cardiac death, MI, and stent thrombosis -- had occurred in and 1.2% of their peers who underwent angiography-guided DES placement (HR 0.36, 95% CI 0.13-0.99), according to , of Korea's Yonsei University College of Medicine, and colleagues.

"These findings were consistent across the clinical (lesion/patient) subgroups and were stronger according to the per-protocol analysis," they wrote in their study published in JACC: Cardiovascular Interventions.

On closer inspection, however, while the IVUS-guided group had substantially lower rates of MI (0% versus 0.4%, HR 0.09, P=0.026), cardiac and death and stent thrombosis rates were no different between groups, Hong's group suggested.

Without an advantage for the hard outcomes of death and stent thrombosis, , of University of Vermont Medical Center in Burlington, suggested in an that it was no wonder that IVUS has not been widely adopted to guide percutaneous coronary intervention (PCI).

"The lack of adoption of routine IVUS is not borne purely of laziness; excellent outcomes achieved without IVUS guidance damper enthusiasm for technology and pharmacology that may be seen as expensive or time consuming," he wrote.

"The key to broader adoption of IVUS-guided PCI may be twofold: 1) convincing clinicians that they are saving lives (or at least preventing stent thrombosis) and 2) demonstrating benefit in the context of an angiographic control group that has a truly high event rate," according to Dauerman. "Unfortunately, the meta-analysis of Shin et al. may not meet this clinical challenge."

The editorialist deemed it unlikely that guidelines will recommend IVUS guidance more strongly based on the current data. "On the other hand, intracoronary imaging -- both IVUS and optical coherence tomography -- remain vital in selected situations."

Hong's group included 2,345 patients who had complex coronary lesions -- chronic total occlusions and diffuse long lesions -- and were enrolled in three randomized trials (RESET IVUS, CTO-IVUS, and IVUS-XPL). Participants received either a zotarolimus- or everolimus-eluting device.

Their findings cannot be generalized to lesions that aren't complex coronary lesions, they acknowledged, adding that 1 year may have been too short of a follow-up period.

"By grouping together three similar trials, the authors drive the discussion towards a patient oriented benefit that goes beyond repeat PCI: death, heart attack, and stent clotting are clearly bad enough to warrant the time required for intracoronary imaging," the editorialist wrote. "But the interventional cardiology community has a long history of limited adoption of all decision aids that are additional to angiography -- coronary physiology, intracoronary imaging and risk scoring systems are easily available and infrequently utilized."

"Thus, resorting to meta-analysis to make a strong point may not sway physicians the way a single, adequately powered randomized trial would."

"These results emphasize an unintended conclusion ... long lesions do not drive up event rates, and long lesions no longer define high-risk PCI," Dauerman added.

"Given advances in stent technology, a truly high-risk PCI group with an excessive stent thrombosis or target lesion revascularization event rate may no longer exist. But, the suggestion of potential improvement in hard outcomes combined with decades of clinical experience in difficult situations may be enough to rewrite the PCI guidelines strongly in favor of selected use of intracoronary imaging.

"Maybe the following fits the spirit of the meta-analysis and the long, hard road of convincing clinicians of the important role of intracoronary imaging: Class I, Level of Evidence A -- Intracoronary imaging, either IVUS or optical coherence tomography, is a vital tool that should be available in all interventional cardiology programs, with operators who are proficient in application of these technologies in selected situations where diagnosis or treatment strategy are unclear."