A systematic two-stent approach to complex coronary bifurcation lesions led to significantly improved clinical outcomes at 1 year, compared with the long-popular provisional stenting technique, in the first randomized trial to prospectively validate a standardized definition of what constitutes a complex bifurcation.
Since the double-kissing (DK) crush technique was employed in 78% of the systematic two-stent procedures, and the two-stent approach provided superior outcomes, it’s reasonable to infer that the DK crush is the preferred technique in patients with truly complex coronary bifurcation lesions (CBLs), Shao-Liang Chen, MD, reported at the virtual annual meeting of the European Association of Percutaneous Cardiovascular Interventions.
He presented the results of the DEFINITION II trial, a multinational trial in which 653 patients at 49 medical centers who fulfilled the criteria for complex CBLs were randomized to a systematic two-stent approach or provisional stenting, with a second stent deployed by interventionalists as needed. Dr. Chen, director of the cardiology department and deputy president of Nanjing (China) Medical University, and coworkers had previously published their standardized criteria for CBLs (JACC Cardiovasc Interv. 2014 Nov;7:1266-76), which they developed by analysis of a large bifurcation cohort; however, until the DEFINITION II trial, the criteria had never been used in a prospective randomized trial.
According to the standardized definition developed by Dr. Chen and associates, complex coronary bifurcation lesions must meet one major and two minor criteria.
- A side branch lesion length of at least 10 mm with a diameter stenosis of 70% or more for distal left main bifurcation lesions.
- For non–left main bifurcation lesions, a side branch diameter stenosis of at least 90% along with a side branch lesion length of at least 10 mm.
- Moderate to severe calcification multiple lesions
- Bifurcation angle of <45 degrees or >70 degrees
- Thrombus-containing lesions
- Main vessel residual diameter <2.5 mm
- Main vessel lesion length of at least 25 mm
Interventionalists were strongly encouraged to utilize the DK crush or culotte stenting techniques in patients randomized to the systematic two-stent approach. In contrast, in the provisional stenting group, where 23% of patients received a second stent, that stent was placed using the T and small protrusion technique 64% of the time.
The primary endpoint was the target lesion failure rate at 1-year of follow-up. Target lesion failure was a composite comprising cardiac death, target vessel MI, and clinically driven target vessel revascularization. The rate was 6.1% in the systematic two-stent group and 11.4% with provisional stenting, for a highly significant 48% relative risk reduction. The difference was driven largely by the systematic two-stent group’s lower rates of target vessel MI – 3.0% versus 7.1% with provisional stenting – and target lesion revascularization, with rates of 2.4% and 5.5%, respectively.
“The underlying mechanisms for the increased target vessel MI rate after the provisional stenting technique are unclear, and further study is urgently warranted,” Dr. Chen said.
There were no significant between-group differences in all-cause mortality or cardiac death, although both endpoints were numerically less frequent in the two-stent group.
The primary safety outcome was the 12-month rate of definite or probable stent thrombosis. This occurred in 1.2% of the systematic two-stent group and 2.5% of the provisional stent patients, a nonsignificant difference.
Discussant Davide Capodanno, MD, PhD, declared the DEFINITE II trial to be “another success for this DK crush technique everyone is talking about recently.”
He noted that, in a recent meta-analysis of 21 randomized, controlled trials including 5,711 patients with bifurcation lesions treated using five different percutaneous coronary intervention techniques, DK crush stood out from the pack. Particularly impressive was the finding that the target lesion revascularization rate in patients treated using the DK crush technique was 64% lower than with provisional stenting (JACC Cardiovasc Interv. 2020 Jun 22;13:1432-44).
Dr. Capodanno said that, although the DEFINITE II results were strongly positive in favor of the systematic two-stent approach and DK crush technique, he’s not convinced of the generalizability of the study results.
“These investigators are very expert in this technique. They invented it. They’ve been using it for 10 years. So of course you may expect excellent results when you have masters of this technique,” observed Dr. Capodanno, a cardiologist at the University of Catania (Italy).
Independent replication of the DEFINITE II findings is needed. Fortunately, two ongoing randomized trials are addressing the issue of how to best treat bifurcation lesions. The EBC-MAIN trial is comparing the provisional approach with the systematic two-stent strategy in patients with left main bifurcation lesions; the study will include the DK crush as well as culotte and TAP PCI techniques, with a primary endpoint consisting of the 12-month rate of death, MI, and target lesion revascularization. And the BBK-3 trial will compare systematic two-stent strategies pitting the culotte against the DK crush, with the primary endpoint being the 9-month rate of angiographic restenosis by quantitative coronary angiography.
“After these trials are complete, we’ll probably know much more about the tailoring of bifurcation techniques for particular patients,” according to Dr. Capodanno.
Simultaneous with Dr. Chen’s presentation, the results of the DEFINITION II trial were published online (Eur Heart J. 2020 Jun 26.doi: 10.1093/eurheartj/ehaa543).
Dr. Chen and Dr. Capodanno reported having no financial conflicts of interest regarding the study, which was funded mainly by the National Science Foundation of China.