Author + information
- Published online November 20, 2017.
- aMinneapolis Heart Institute, Minneapolis, Minnesota
- bVA North Texas Healthcare System and University of Texas Southwestern Medical School, Dallas, Texas
- ↵∗Address for correspondence:
Dr. Emmanouil S. Brilakis, Minneapolis Heart Institute, 920 East 28th Street, #300, Minneapolis, Minnesota 55407.
Percutaneous coronary intervention (PCI) is an established treatment for unprotected (i.e., no bypass grafts to the left anterior descending artery and/or the circumflex) left main (ULM) lesions (1). Provisional stenting (i.e., stenting the main vessel and “jailing” the side branch, which is only treated if it becomes severely stenotic or occluded) is currently favored in most non-left main bifurcation lesions, because it is simple and easy to perform and often provides satisfactory results (1). Several 2-stent techniques have been developed for bifurcations involving both the main and the side branch, such as the T-stent, the culotte, and the double kissing crush (DK crush) technique. T-stent is usually used when the side branch originates at an approximately 70° to 90° angle from the main vessel, whereas culotte and DK crush are the currently preferred 2-stent techniques for <70° angle bifurcations. In this issue of the Journal, the DKCRUSH-V trial reports novel and important data demonstrating both incremental “gain” and some “pain” with DK crush over provisional stenting for ULM bifurcation lesions (2).
The DKCRUSH-V trial randomized 482 patients with true ULM bifurcation lesions to DK crush or provisional stenting at 26 centers around the world (2). At 12 months, use of DK crush resulted in lower rates of target lesion failure, driven by lower rates of definite/probable stent thrombosis and periprocedural myocardial infarction early after PCI (in the first 30 days). The number needed to treat to prevent target lesion failure was 20 overall, and 9 in patients with more complex ULM lesions (longer lesions, with more severe angiographic stenosis, and at least 2 other high-risk features, such as severe calcification, intracoronary thrombus, multiple bifurcations, and acute or obtuse angulation).
The DKCRUSH-V trial provides the best evidence to date on treatment of ULM bifurcation lesions, showing that DK crush is superior to provisional stenting. Whether some may consider periprocedural myocardial infarction a “soft” endpoint, stent thrombosis, which was lower in the DK crush group, is definitely a “hard” endpoint, with high mortality. Hence, it is likely that with higher use of DK crush, the results of both the EXCEL (Evaluation of XIENCE Everolimus Eluting Stent Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) and NOBLE (Nordic-Baltic-British Left Main Revascularization Study) trials (which both used mainly provisional stenting) would have been significantly more favorable for the PCI arm.
DK crush is the exception to the empiric rule “simpler is better,” likely because it provides better stent expansion and because it ensures coverage of the ostium of the side branch. During ULM stenting, the most common location for in-stent restenosis is the circumflex ostium, which may be harder to treat after it has been jailed by a crossover stent into the left anterior descending artery. In the DKCRUSH-V trial, although a second stent was placed in nearly one-half of the provisional group patients, restenosis was numerically lower in the DK crush group. The complication rates were the highest among the provisional stenting patients who needed an additional stent in the side branch, hence trying to “keep it simple” and failing is worse (and likely more “painful” for the operator as well).
The DKCRUSH-V trial establishes DK crush as the third standard strategy for ULM stenting, with the other 2 being use of drug-eluting stents and intravascular ultrasound (IVUS) (1). In the DKCRUSH-V trial, second-generation drug-eluting stents, mainly the Xience everolimus-eluting stent (Abbott Vascular, Santa Clara, California), were used in most study patients; however, overall use of IVUS was relatively low (approximately 42%). Higher IVUS use might further improve outcomes in both groups, although the relative benefit of the DK crush technique was similar in the IVUS and no-IVUS subgroups of the study.
Another ongoing trial is comparing provisional stenting with a planned dual stent technique in ULM lesions, the EBC MAIN study (European Bifurcation Club Left Main Study; NCT02497014). In contrast to the DKCRUSH-V trial, the EBC MAIN study leaves the choice of technique to the discretion of the operator, recommending use of culotte, DK minicrush, and T or T and protrusion. The primary endpoint of the EBC-MAIN study is the composite of death, myocardial infarction, and target lesion revascularization at 12 months, and the primary results are anticipated in late 2018.
DK crush has many steps and can be challenging to perform. First, it may be difficult to rewire the side branch after each stent implantation. Use of a dual lumen or angulated microcatheter may assist with this task and also minimize the possibility of the wire crossing under a stent strut, hindering subsequent equipment advancement. Second, advancing a balloon to the side branch can be tedious: use of low profile balloons, the Threader (balloon/microcatheter, Boston Scientific, Natick, Massachusetts), or the Glider balloon (Trireme Medical, Pleasanton, California) may help, but occasionally, another wire may need to be advanced into the side branch through a different pathway to allow balloon passage. Third, delivery of the main branch stent after the first kissing balloon inflation can be challenging, requiring additional pre-dilation and/or use of techniques to increase guide catheter support, such as use of side branch anchoring and guide catheter extensions. These challenges are more likely to arise with more extreme angulation and in the presence of calcification, and may require significant operator expertise and technical dexterity to overcome. It is, therefore, not surprising that DK crush required more time (16 more minutes or 19% more time) than provisional stenting in the DKCRUSH-V trial.
Who should perform ULM PCI? The DKCRUSH-V trial required the primary operators to have performed ≥300 PCIs per year for 5 years, including at least 20 left main PCIs 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 (3). Although there is ongoing controversy about the impact of PCI volume on outcomes (3), concentrating ULM PCI cases to centers experienced in performing complex PCI would likely improve outcomes, regardless of technique used.
Not all seasoned, high-volume operators are proficient in the DK crush technique. In the DKCRUSH-V trial, operators had to demonstrate proficiency in the DK crush technique in 3 to 5 cases before being allowed to enroll patients. Similar to chronic total occlusion interventions (4), there is likely a learning curve before optimal outcomes are achieved with DK crush, requiring teaching, adequate practice, and ideally, confirmation that adequate results are achieved using intravascular imaging.
The Growth Mindset
DK crush is a perfect illustration of the “no pain, no gain” concept: doing DK crush in ULM bifurcation lesions will be more challenging than provisional stenting, but will benefit the patients, which is what matters the most. It is our strong belief that coronary interventionalists will demonstrate an evidence-based “growth mindset” (5) and will adopt DK crush as their standard strategy for treating ULM bifurcations (Figure 1).
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Brilakis has received consulting/speaker honoraria from Abbott Vascular, Asahi, Amgen, Elsevier, GE Healthcare, and Medicure; has received research support from Osprey and Boston Scientific; and his spouse was an employee of Medtronic. Dr. Burke has received consulting and speaking honoraria from Abbott Vascular and Boston Scientific. Dr. Banerjee has received research grants from Boston Scientific (institutional), Merck (institutional), Gilead, and the Medicines Company; has received consultant/speaker honoraria from Covidien and Medtronic; has received honoraria from Gore, CSI, AstraZeneca, and Janssen; has intellectual property in HygeiaTel; and his spouse has ownership in MDCARE Global.
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