A new observational study of delayed lesions by combined fractional flow reserve (FFR) and coronary flow reserve (CFR) assessments found that untreated vessels with abnormal FFR but intact CFR compared to vessels with FFR greater than 0.8 and no worse are a CFR greater than or equal to two when medically treated.

The results were published today at TCT Connect, the 32nd Annual Scientific Symposium of the Cardiovascular Research Foundation (CRF).

The role of invasive CFR assessment in the current era remains unclear as FFR has become a reference standard for decisions about revascularization. While observational data from invasive and non-invasive instruments have shown that lesions with intact CFR perform well, few of these studies simultaneously assessed the FFR. To address the limitations of the current literature, the researchers designed and conducted the DEFINE-FLOW study.

A total of 455 patients were enrolled at 12 sites in six countries. Of the patients included, 430 patients (533 lesions) were treated with the protocol and followed up for two years. Stable coronary lesions were measured at least in duplicate with both FFR and CFR measurements, with the records being reviewed in the central core laboratory. Treatment followed local measurements according to a unified protocol, with only lesions with FFR ≤ 0.8 and CFR 2.0 receiving initial medical therapy.

The primary endpoint was the combination of all cause death, myocardial infarction, and revascularization at two years. The study results for MACE were 5.8% for FFR- / CFR-, 10.8% for FFR + / CFR-, 12.4% for FFR- / CFR + and 14.4% for FFR + / CFR + (after PCI). The difference between FFR + / CFR- and FFR- / CFR- was 5.0% (95% CI -1.5% to + 11.5%, p-value 0.065 for non-inferiority). Therefore, the study found that vessels with abnormal FFR ≤ 0.8 but intact CFR ≥ 2.0 did not have non-inferior results when medically treated compared to FFR> 0.8 and CFR ≥ 2.0.

“Since the study was an observational study, it is not clear what results would have been achieved with FFR + / CFR- lesions if they had undergone PCI instead of medical therapy,” said Dr. Nils Johnson, Associate Professor of Medicine and Weatherhead Distinguished Chair of Heart Disease, Department of Cardiology, Department of Medicine, and Weatherhead PET Imaging Center at McGovern Medical School of UT Health, Houston and Memorial Hermann Hospital – Texas Medical Center. “This study had a number of limitations, such as few lesions with severe FFR / CFR as well as non-blind subjects and physicians. The limitations associated with the results make this study a hypothesis-generating study that helps better understand the role of invasion CFR and how to handle CFR / FFR discordances. ”

COMBINE (OCT-FFR) results were provided at TCT Connect by the Cardiovascular Research Foundation

Quote: The results of the DEFINE-FLOW study (2020, October 17) were accessed on October 17, 2020 from https://medicalxpress.com/news/2020-10-results-define-flow.html

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