Background: Management of coronary lesions with fractional flow reserve values in the gray zone (0.75-0.80) remains controversial due to conflicting data on the performance versus deferral of revascularization.
Methods: We performed a systematic review and meta-analysis of 7 observational studies including 2683 patients that compared the outcomes of deferred versus performed revascularization of coronary lesions with gray-zone fractional flow reserve values.
Results: During a mean follow-up of 31±9 months, the incidence of major adverse cardiovascular events (12.54 % versus 11.25%; odds ratio [OR], 1.64 [95% CI, 0.78-3.44]; P=0.19, I2=84%), cardiac mortality (1.25% versus 0.72%; OR, 1.78 [95% CI, 0.58-5.46]; P=0.31, I2=18%), and myocardial infarction (1.28% versus 2.66%; OR, 0.79 [95% CI, 0.22-2.79]; P=0.71, I2=65%) was similar with deferral versus performance of revascularization in coronary lesions with gray-zone fractional flow reserve. Deferral of revascularization was associated with a higher incidence of target vessel revascularization (9.12% versus 5.78%; OR, 1.85 [95% CI, 1.03-3.33]; P=0.04, I2=62%). When the analysis was limited only to studies that used percutaneous coronary intervention for revascularization, deferred revascularization remained associated with a higher risk of target vessel revascularization (18% versus 7.3%; OR, 3.04 [95% CI, 1.53-6.02]; P<0.001) and was associated with a higher risk of major adverse cardiovascular event (23.2% versus 13.4%; OR, 3.38 [95% CI, 1.92-5.95]; P<0.001).
Conclusions: In lesions with gray-zone fractional flow reserve, revascularization was associated with a similar incidence of major adverse cardiovascular event but a lower incidence of target vessel revascularization over a mean follow-up of approximately 2.5 years.
Clinical trial registration: URL: https://www.crd.york.ac.uk/prospero/. Unique identifier: CRD42019128076.
Keywords: fractional flow reserve; percutaneous coronary intervention; physiological assessment of coronary lesions.