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Study supports routine physiologic assessment to guide revascularization

Reuters Health - 16/11/2020 - In patients with coronary-artery disease (CAD), having percutaneous coronary intervention (PCI) according to evidence-based fractional flow reserve (FFR) thresholds is associated with improved clinical outcomes compared to not having PCI, a large retrospective study shows.

The study also suggests potential harm from performing PCI outside of FFR thresholds.

Based on clinical-trial data, PCI is generally recommended for lesions with ischemic FFR values (FFR <=0.80) but not for lesions with nonischemic FFR values (FFR >0.80) because it has not been demonstrated to be beneficial and may be harmful, the study team explains in JAMA.

"There has been a paucity of data in the real world to see whether FFR is used appropriately or whether what we see in the randomized trials are translated to practice," Dr. Dennis Ko of the University of Toronto and the Institute for Clinical Evaluative Sciences (ICES), in Canada, told Reuters Health by email.

"One of important findings is that following the FFR threshold works in the real world," said Dr. Ko. "We were also surprised to find about 12% of patients who had negative FFR got PCI. And those patients actually had worse outcome (we were expecting nil impact)."

The researchers took a look back at more than 9,000 adults with CAD (mean age, 65 years; 35.3% women) who underwent single-vessel FFR measurement, including 2,693 with an ischemic FFR and 6,413 with a nonischemic FFR.

In the ischemic-FFR cohort, 75.3% received PCI and 24.7% received medical therapy only. In this cohort, at five years, PCI was associated with a significantly lower rate of major adverse cardiac events (MACE) compared with no PCI (31.5% vs. 39.1%; hazard ratio, 0.77). Rates of MACE were also significantly lower with PCI at 30 days and one year.

In the nonischemic-FFR cohort, 12.6% received PCI and 87.4% were treated with medical therapy only. In this cohort, PCI was associated with a significantly higher rate of MACE at five years compared with no PCI (33.3% vs. 24.4%; HR, 1.37). MACE rates were also significantly higher with PCI than without at 30 days and one year.

The fact that roughly 25% of patients with ischemic FFR did not undergo PCI is in keeping with a prior study showing that revascularization is underutilized in about 30% of patients with appropriate indications, the authors note in their paper.

They say the reasons why clinicians may opt to perform PCI for nonischemic lesions is not clear. "Regardless of the reason, this study suggests that deviating from accepted FFR thresholds is more common in routine clinical practice than previously reported from registries," they write.

Summing up, they say their findings "support current class III recommendations against revascularization in the absence of ischemia and suggest clinicians avoid performing PCI for nonischemic lesions."

The author of a linked editorial says the findings "confirm a significant early and sustained benefit of revascularization for lesions found by invasive physiologic assessment to have an FFR of 0.80 or less, and significant harm associated with PCI of lesions found nonischemic by an FFR of greater than 0.80."

"This study serves as an affirmation that the application of invasive physiologic testing into routine clinical practice accompanied by adherence to recommended thresholds for deciding to proceed with or defer revascularization is associated with improved outcomes," writes Dr. Richard Bach of Washington University Medical Center in St. Louis, Missouri.

It follows, he adds, that "failure to incorporate such physiologic assessment into the routine practice of diagnostic cardiac catheterization and clinical decision-making for managing coronary artery disease represents a missed opportunity to provide better outcomes for patients with coronary artery disease."

Dr. Bach notes the results should be "welcome news to clinicians who were awaiting further evidence that in everyday practice physiologic guidance can help optimize the outcomes of revascularization by objectively selecting patients who will benefit from PCI and to avoid the risks of revascularization by better identifying those who will not."

The study had no commercial funding.

By Megan Brooks

SOURCE: https://bit.ly/3nniAB8 and https://bit.ly/38HwoTc JAMA, online November 13, 2020.

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