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DENVER – When stenting unprotected left main bifurcation lesions, a double kissing (DK) crush technique yields better outcomes than the typical provisional approach, the DKCRUSH-V trial showed.

For the primary endpoint of 1-year target lesion failure (cardiac death, target vessel myocardial infarction, or clinically-driven target lesion revascularization), DK crush reduced relative risk by 58% versus stenting the main vessel and "jailing" the side branch (rate 5.0% versus 10.7%, P=0.02).

The overall number needed to treat was 20, and just nine in patients with longer and more severely stenosed and otherwise more complex lesions. Shao-Liang Chen, MD, PhD, of China's Nanjing Medical University, reported the findings here at the Transcatheter Cardiovascular Therapeutics meeting and online in the .

DK crush also reduced the "soft" endpoint of target vessel myocardial infarction I (0.4% versus 2.9%, P=0.03) and the "hard" one of definite or probable stent thrombosis (0.4% versus 3.3%, P=0.02), with favorable trends for clinically driven target lesion revascularization and angiographic restenosis within the left main complex.

The trial "provides the best evidence to date on treatment of unprotected left main bifurcation lesions, showing that DK crush is superior to provisional stenting," Emmanouil Brilakis, MD, PhD, of the Minneapolis Heart Institute, and colleagues wrote in an accompanying editorial.

"It is our strong belief that coronary interventionalists will demonstrate an evidence-based 'growth mindset' and will adopt DK crush as their standard strategy for treating unprotected left main bifurcations," they added.

But it wasn't an unqualified win.

Brilakis's group cautioned about the learning curve for the "challenging" technique, even among seasoned, high-volume operators. The trial required operators to show proficiency in three to five cases before being allowed to enroll patients as well as an annual PCI volume of at least 300 cases for 5 years, including at least 20 left main cases per year.

"These numbers are unrealistic for many U.S. operators, because the median annual PCI volume in the United States is 59 cases, and 44% of U.S. operators perform <50 PCIs per year," the editorialists wrote. "Although there is ongoing controversy about the impact of PCI volume on outcomes, concentrating unprotected left main PCI cases to centers experienced in performing complex PCI would likely improve outcomes, regardless of technique used."

Mitchell Krucoff, MD, of the Duke Clinical Research Institute in Durham, North Carolina, commented at a press conference for the late-breaking clinical trial that the way to learn this technique is not in the left main, but in other bifurcation settings. "Once you have experience then the left main is the next step."

And there are lots of U.S. operators with experience in the DK crush approach outside of the left main, David Cohen, MD, of Saint Luke's Mid-America Heart Center in America Heart Institute in Kansas City, Missouri, and a study discussant at the press conference, told 木瓜直播. "The technique is identical."

The researchers acknowledged the challenge presented by the technique as well as the longer procedures (16 min on average, 19% more time overall).

But they pointed, too, to the challenge of rescue stenting required in about 47% of the provisional stenting cases, "a relatively high rate reflecting the fact that we enrolled true bifurcation lesions of the distal left main ... "

"By contrast, although DK crush stenting is a more complex technique that entails more upfront procedural time and contrast, it offers a more controlled strategy to treat the entire left main complex, and affords more reliable lesion coverage and greater stent expansion of the ostial left circumflex coronary artery, which in the present study resulted in improved clinical and angiographic outcomes compared with a provisional stenting approach."

Press conference moderator Roxana Mehran, MD, of the Icahn School of Medicine at Mount Sinai in New York City, agreed it could be argued these should only be done in top centers. "It's important to note there are lots of other techniques that haven't been tested against this, so yes, if you go after provisional versus this, it looks like it's better."

The randomized trial included 482 patients from 26 centers in five countries (one center in the U.S.) with true distal left main bifurcation lesions (Medina 1,1,1 or 0,1,1). The mean angle of the distal left main bifurcation was about 78 degrees, "which should have been favorable for provisional stenting," the researchers noted.

The 30-day results also showed less target lesion failure with the DK crush approach (0.4% versus 2.9%, P=0.03) and a trend for less stent thrombosis in particular (0.4% versus 2.5%, P=0.09). There were fewer cardiac deaths at 30 days (0% versus 1.7%, P=0.046), but not 1 year (1.2% versus 2.1%, P=0.48).

Routine angiography at 13 months showed half as many patients with restenosis at any location within the left main bifurcation complex in the DK crush group as with provisional stenting but without reaching statistical significance (7.1% versus 14.6%, P=0.10).