Deferring coronary revascularization based on a nonischemic resting full-cycle ratio (RFR) may be associated with favorable 2-year cardiovascular outcomes, with similar rates of major adverse cardiovascular events across nonischemic RFR values. However, patients with lower nonischemic RFR values underwent repeat revascularization more frequently.
Researchers evaluated 773 patients with 1,012 angiographically intermediate coronary lesions whose revascularization was deferred following RFR assessment at the University Hospital Cologne between 2016 and 2022. Patients with ST-segment elevation myocardial infarction, non-ST-segment elevation myocardial infarction, cardiogenic shock, technically unsuitable lesions, or incomplete follow-up were excluded. RFR values greater than 0.89 were considered nonischemic and supported deferral of revascularization. To examine outcomes within the nonischemic range, lesions were stratified into RFR values below 0.93, 0.93 to 0.95, and greater than 0.95. The primary outcome was the 2-year incidence of major adverse cardiovascular events (MACE), defined as cardiovascular death, myocardial infarction, or stroke. Secondary outcomes included all-cause mortality, vessel-oriented composite outcomes, and repeat revascularization.
At 2 years, the lesion-based MACE rate was 8%, and the patient-based rate was 8%. Rates were similar across the three RFR groups, with no statistically significant differences in MACE, cardiovascular death, myocardial infarction, stroke, or vessel-oriented composite outcomes. Cardiovascular death occurred in 5% of patients, myocardial infarction in 2%, stroke in 2%, and all-cause mortality in 11%.
Although major cardiovascular outcomes were comparable across RFR groups, repeat revascularization occurred more frequently among patients with RFR values below 0.93. These patients had approximately three times the likelihood of target-vessel revascularization and more than twice the likelihood of ischemia-driven target-vessel revascularization compared with patients whose RFR values exceeded 0.95. The researchers noted that this difference may have been driven by worsening or new-onset angina because hard cardiovascular endpoints remained similar across groups.
In analyses examining factors associated with adverse outcomes, older age, chronic obstructive pulmonary disease, peripheral artery disease, atrial fibrillation, diffuse coronary artery disease, and heavy coronary calcification were associated with higher rates of MACE. Following multivariable adjustment, chronic obstructive pulmonary disease remained independently associated with adverse events.
The researchers concluded that the established RFR threshold for deferring revascularization appeared reliable for predicting major cardiovascular outcomes in routine clinical practice. They also suggested that patients with RFR values below 0.93, particularly those with diffuse coronary artery disease or heavy calcification, may benefit from additional physiologic or intravascular imaging assessment, including complementary fractional flow reserve assessment, before treatment decisions are finalized.
The study was limited by its single-center observational design, which cannot eliminate residual confounding. Clinical outcomes were determined through medical record review and telephone follow-up, and some deaths could not be definitively attributed to the deferred lesion. In addition, the relatively small number of patients with RFR values below 0.93, low event rates, and differences in baseline characteristics between RFR groups may have affected the precision of the findings.
"Such lesions may warrant further evaluation, particularly in the presence of additional high-risk features like severe calcification or diffuse coronary artery disease, potentially through intravascular imaging and complementary FFR assessments," wrote lead study author Stephan Nienaber, of the University Hospital Cologne, and colleagues.
Disclosures: M. Adam reported receiving personal fees from multiple medical device companies. Stephan Baldus reported research grants and lecture honoraria from several cardiovascular device manufacturers. Marcel Halbach reported lecture fees from Abbott. Hendrik Wienemann reported consultancy fees and travel grants from JenaValve Technology. The remaining authors reported no conflicts of interest.
Source: Clinical Research in Cardiology