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SAN FRANCISCO -- Taking a more conservative approach to deciding which coronary lesions need percutaneous intervention did not harm patient outcomes, a randomized trial showed.

The 1-year rate of all-cause death, myocardial infarction, and any revascularization was 7.3% when stenosis of greater than 70% was used as the deciding threshold and 6.8% when stenosis of greater than 50% was used (HR 1.05, 95% CI 0.63-1.74), according to Hyeon-Cheol Gwon, MD, PhD, of Samsung Medical Center in Seoul, South Korea.

The difference met criteria for noninferiority (P=0.0055), Gwon reported at the Transcatheter Cardiovascular Therapeutics meeting here.

"The revascularization of [an] angiographically intermediate lesion can be deferred safely," he said.

Other cardiologists who commented on the results agreed that using an angiographic cutoff of 50% stenosis is not helpful for deciding which lesions to revascularize. But they argued for the need for more precise information about lesions in the intermediate range of 50% to 70% stenosis using fractional flow reserve (FFR).

"Revascularization of all 50% lesions [is] not necessary but I still think that there's a place for physiologic assessment of the intermediate lesion," said , of the Hopital du Sacre-Coeur de Montreal.

, of the Mayo Clinic in Rochester, Minn., agreed.

"What FFR measurements have taught us ... is if you look at the 50% to 70% stenoses, intermediate stenoses, there is a wide range of FFR in that group and it seems to correlate with clinical events," he said in an interview.

"We've gone beyond visual assessment," he added.

Gwon argued that there was a need to compare outcomes when using the more aggressive angiographic cutoff of 50% stenosis for PCI -- as indicated in U.S. guidelines -- or when using the more conservative cutoff of 70% stenosis -- as indicated in the European guidelines -- because FFR is used in only a minority of cases. Most centers, he said, still rely on angiographic assessment.

He and his colleagues explored the issue in the , an open-label, randomized study conducted at 16 centers in South Korea. The trial included 899 patients (mean age about 65) who had a target lesion resulting in 50% to 70% stenosis -- as measured by quantitative coronary angiography -- in a native coronary artery suitable for PCI. They were randomized to have only those lesions greater than 70% stenosis stented or to have lesions greater than 50% stented.

The Xience V everolimus-eluting stent was used whenever PCI was indicated. Using the more conservative 70% cutoff, nearly half (47.4%) of the patients did not receive any stents at all.

Through 1 year, clinical outcomes were comparable between the two groups. The rate of death or MI (leaving out the revascularization part of the primary endpoint) was numerically lower in the conservative group, but the difference did not reach statistical significance (1.4% versus 2.7%; HR 0.50, 95% CI 0.19-1.33).

There also was no difference in the rate of any revascularization (6.8% with conservative versus 4.8% with aggressive; HR 1.42, 95% CI 0.80-2.52), although the rate of revascularization of the target lesion only was higher in the conservative group (4.1% versus 1.7%; HR 2.47, 95% CI 1.02-5.95).

The absolute rate was still low in both groups, Gwon said.

In a subgroup analysis, there was a significant interaction with age (P=0.02), such that patients 65 and older tended to do better with the conservative strategy and younger patients tended to do better with the aggressive strategy.

Gwon acknowledged that the study was limited by the wide noninferiority margin used, the lack of statistical power for hard clinical endpoints, the short duration of follow-up, and the lack of FFR measurements.

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