SAN FRANCISCO – The double-kissing crush approach to stenting an unprotected left main coronary artery at the distal bifurcation produced clearly better 1-year clinical outcomes than did an alternative way to stent at the bifurcation, the culotte approach, in a multicenter, randomized trial in China with 419 patients.
The survival rate of patients free of major adverse coronary events 1 year after treatment was 94% for the double kissing (DK) crush technique and 84% for the culotte technique, a statistically significant benefit for DK crush for the study’s primary endpoint, Dr. Jun-Jie Zhang reported at the American College of Cardiology/Cardiovascular Research Foundation Innovation in Intervention Summit.
Mitchel L. Zoler/IMNG Medical Media
Dr. Jun-Jie Zhang
This definitive clinical comparison, DKCRUSH-III (DK Crush Versus Culotte Stenting for the Treatment of Unprotected Left Main Bifurcation Lesions), is the third in a series of large randomized trials led by Dr. Zhang and his associates to compare the DK crush method of coronary bifurcation stenting with other stenting approaches. In DKCRUSH-1 they found that DK crush worked better than classical crush for treating coronary bifurcations of all types, not just in unprotected left main coronaries (Eur. J. Clin. Invest. 2008;38:361-71). In DKCRUSH-II they compared DK crush with provisional side-branch stenting in a variety of coronary artery types, and found that while DK crush was associated with significantly less restenosis it produced no significant difference in 1-year major adverse coronary events compared with provisional stenting (J. Amer. Coll. Cardiol. 2011;57:914-20).
Dr. Zhang, in collaboration with Dr. Shao-Liang Chen and their associates at Nanjing First Hospital in China, pioneered the DK crush technique, reporting results from their first 20 patients in 2005 (Chinese Med. J. 2005;118:1746-50).
Their new trial notably focused exclusively on distal bifurcations in the unprotected left main coronary artery.
"We know that left main midshaft lesions respond very well to PCI [percutaneous coronary intervention], but distal left main lesions, which represent the majority of left main lesions, have a higher 1-year event rate, mostly related to the ostium circumflex," commented Dr. Gary S. Mintz, chief medical officer of the Cardiovascular Research Foundation in Washington. "There is growing interest in stenting left main lesions among U.S. interventionalists. It is the last frontier for U.S. interventionalists but is routinely done in Asia. The goal is to get the largest cross-sectional area throughout the bifurcation, but the question is how to do that, and what produces the least amount of restenosis at the circumflex ostium? That is the Achilles heel of using two stents at the bifurcation."
While the new results seem to clearly establish the superiority of DK crush over the culotte method, the trial did not address whether stenting of the side branch is better than leaving it unstented or using a different PCI approach.
"When the bifurcation angle is more than 70 degrees, most would do neither DK crush nor culotte; if they felt they had to stent [the side branch] they would use a T stent technique," commented Dr. Gregg W. Stone, professor of medicine and director of cardiovascular research and education at Columbia University in New York.
Mitchel L. Zoler/IMNG Medical Media
Dr. Gary S. Mintz
The DKCRUSH-III trial enrolled patients between March 2009 and October 2011 at 18 Chinese centers. The patients averaged about 64 years old, and nearly four-fifths were men. Their average SYNTAX score was about 31, and their New Risk Stratification Score averaged 26. Almost two-thirds of the patients received everolimus-eluting coronary stents (J. Amer. Coll. Cardiol. Intv. 2010;3:632-41).
Quantitative coronary angiography done about 7 months after PCI in about 84% of the patients in both arms showed no significant differences in patency of the left main coronary, but the side-branch patients in the culotte group had a significantly higher rate of late lumen loss. The overall rate of side-branch restenosis at 7 months was 7% in the DK crush group and 13% in the culotte group.
The 1-year combined rate of cardiac death, myocardial infarction, or clinically driven need for target-lesion or target-vessel revascularization – the primary endpoint – was 6% in the DK crush group and 16% in the culotte group, a significant difference, reported Dr. Zhang, an interventional cardiologist at Nanjing First Hospital. The difference in the rates between the two treatment arms was primarily driven by a difference in the need for revascularization.
A set of four prespecified subgroup analyses showed that the DK crush method was significantly better than the culotte method in three of the high-risk subgroups: patients with a bifurcation angle of 70 degrees or greater, patients with a SYNTAX score of 23 or greater, and patients with a New Risk Stratification score of 20 or greater. In the fourth high-risk subgroup – patients with diabetes – DK crush was also superior, but the difference just missed statistical significance.