ISAR-LEFT MAIN 2 Published: Second-Generation DES Comparable in Left Main CAD

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In patients with unprotected left main coronary artery disease, second-generation zotarolimus-eluting stents (ZES) and everolimus-eluting stents (EES) provide comparable clinical and angiographic outcomes out to 1 year, according to results from ISAR-LEFT Main-2 published online August 21, 2013, ahead of print in the Journal of the American College of Cardiology.

The study was originally presented in October 2012 at the annual Transcatheter Cardiovascular Therapeutics scientific symposium in Miami Beach, FL.

For ISAR-LEFT MAIN 2, Julinda Mehilli, MD, of the Munich University Clinic (Munich, Germany), and colleagues randomized 650 patients with unprotected left main coronary artery lesions to either ZES (Endeavor Resolute, Medtronic CardioVascular, Santa Rosa, CA; n = 324) or EES (Xience, Abbott Vascular, Abbott Park, IL; n = 326) from December 2007 to September 2011 at 4 European institutions. All patients either refused or were unable to undergo surgery. Angiographic follow-up was conducted after 8 months in 73% of ZES and 69% of EES patients; clinical follow-up at 12 months included all patients.

Similar Performance

At 1 year, the cumulative incidence of the composite primary endpoint (death, MI, and TLR) was similar in both the ZES and EES groups (17.5% vs. 14.3%; RR 1.26; 95% CI 0.85-1.85; P = 0.25), nullifying the inferiority hypotheses for ZES (P < 0.001 for noninferiority). Additionally, there were no differences between the 2 groups in any other adverse outcomes (table 1).

Table 1. Clinical Outcomes at 1 Year

Three patients in the ZES group (0.9%) and 2 patients in the EES group (0.6%) experienced definite/probable stent thrombosis at 1 year (P < 0.99).

Moreover, when patients were broken into prespecified subgroups, ZES and EES treatment resulted in similar outcomes. For example, diabetic patients assigned to ZES had no greater risk for the primary endpoint at 1 year than those in the EES group (RR 1.24; 95% CI 0.69-2.24; P = 0.47).

Angiographic restenosis was 21.5% with ZES and 16.8% with EES (RR 1.28; 95% CI 0.86-1.92; P = 0.24) with a median interval to repeat coronary angiography of 203 days.

Despite Weaknesses, Study Shows Equivalence

Both “stent platforms provide comparable clinical and angiographic outcomes out to 1-year follow-up when used for treatment of [unprotected left main coronary artery] lesions in a relatively unselected population,” Dr. Mehilli and colleagues write.

However, they point out that the study would have benefited from a third cohort of patients treated with CABG or first-generation DES. Additionally, the lower-than-expected adverse event rate negatively impacts the study’s statistical strength by reducing its power and because the selected noninferiority margin “represents a larger relative proportion of the event rate in the control group than the predefined proportion for sample-size calculation,” the researchers conclude.

Study Details

Treatment groups were well matched in terms of baseline characteristics. About one-third of patients presented with ACS, more than half with prior PCI, and about 30% with history of MI. Most patients in both groups had lesions in the distal area of the left main coronary artery.

Single stenting was the preferred technique for distal bifurcation lesions, with culotte stenting being the recommended strategy if 2 stents were needed.

 

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Source:
Mehilli J, Richardt G, Valgimigli M, et al. Zotarolimus- versus everolimus-eluting stents for unprotected left main coronary artery disease. J Am Coll Cardiol. 2013;Epub ahead of print.

 

 

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