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

MIAMI BEACH, FLA.—Second-generation everolimus- and zotarolimus- eluting stents are safe and effective in patients with unprotected left main coronary artery lesions, according to late-breaking results from the ISAR-LEFT MAIN 2 randomized controlled trial presented at TCT 2012.

“Both Endeavor Resolute and Xience stents provide similar clinical and angiographic outcomes at 1-year follow-up in this high-risk patient population,” said Julinda Mehilli, MD, of Klinikum der Universitaet Munich in Germany, who presented the study’s results.

In the first trial of second-generation stents in unprotected left main coronary artery disease, Mehilli and colleagues randomized 650 patients with such lesions to either a ZES (Endeavor Resolute, Medtronic; n=324) or EES (Xience, Abbott; n=326); all patients either refused or could not 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 outcomes

At 1 year, a slightly  higher percentage of  ZES patients met the primary endpoint of MACE (death, MI, TLR), but the difference was not significant (see Figure) Overall, the ZES met the criteria for noninferiority compared with the EES. There was also no difference with regard to death or MI, death MI or stroke, all-cause mortality, TLR, and left main coronary artery restenosis.

Rates of stent thrombosis were low, at 0.6% definite and 0.3% probable stent thrombosis in the ZES group and 0.6% and none in the EES group. A subgroup analysis showed no significant differences in MACE rates based on diabetes status, Parsonnet score, or EuroSCORE. The two stents were also similar with regard to restenosis rates; angiographic restenosis was found in 21.5% of ZES and 16.8% of EES patients (P=.20).

“This is reassuring, because it shows that with what are probably the most advanced second-generation stents we have available, the results in terms of safety are quite good in the left main,” said Antonio Colombo, MD, of San Raffaele Hospital in Milan, Italy, during the discussion period. He pointed out, though, that revascularization rates are still high, and that bypass would still perform better in that regard; TLR rates were 11.7% in the ZES patients and 9.4% in the EES group. “So these advanced stents are not yet perfect if we want to beat bypass in terms of revascularization,” he said.

The study 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 a history of MI. Most patients in both groups had lesions in the distal area of the left main coronary artery.