Fractional flow reserve (FFR) makes a different impact on treatment decisions if diabetes is involved, registry data showed.
The proportion for which FFR would reclassify the treatment strategy was similar between those with and without diabetes (41.2% vs 37.5%, P=0.13) in two merged registries. Compared with controls, however, diabetic patients were more likely to be reclassified from medical therapy to revascularization than the other way around.
Among diabetic patients, FFR-based deferral of stenting or surgery resulted in an 8.4% 1-year rate of major adverse cardiovascular events (MACE: all-cause death, MI, or unplanned revascularization) compared to 13.1% for those who proceeded with revascularization (P=0.04).
This was in line with the rate among non-diabetic patients who had revascularization deferred due to FFR (7.9%, P=0.87), “despite patients with diabetes having a higher CAD burden and complexity” in the PRIME-FFR analysis led by Eric Van Belle, MD, PhD, of Centre Hospitalier Universitaire de Lille, France, reported online in JAMA Cardiology.
People in whom FFR was disregarded had the highest 1-year MACE rates regardless of diabetes status. These events were similarly likely between reclassified and non-reclassified patients (9.7% vs 12.0%, P=0.37).
Patients included in the study came from the Portuguese POST-IT and French R3F registry studies (n=1,983). These were all-comers who had routine FFR at the time of coronary angiography showing at least one intermediate stenosis. FFR was performed in 1.4 lesions per patient.
Roughly three-quarters of the participants were men, and mean age was 65 years. Approximately one-third of the patients had diabetes.
The diabetic group had a unique clinical profile and different lesion characteristics, notably a lower FFR and more complex B2/C lesions despite their mean percentage of angiographic stenosis being similar to that of controls.
“Diabetes has the potential to impair microvascular responsiveness to hyperemia. As such, FFR could theoretically underestimate lesion severity. However, in our study within each stratum of stenosis severity, FFR was lower in patients with diabetes,” Van Belle and colleagues noted.
Given the patients included in the study, the results may not extend to people with angiographically severe multivessel disease or tight lesions, according to the authors.
“In addition, our data cannot speak to the relative safety of a strict FFR vs angiography-based approach because there was no formal control group in which patients were managed according to angiography findings alone,” they cautioned, adding that future randomized trials are needed to study FFR-based strategies for the clinical management of individuals with diabetes.
For now, the available literature on this subject is scarce, conflicting, and mainly derived from retrospective small cohorts, Van Belle’s team said.
R3F was supported by grants from Abbott (St. Jude Medical) and Biotronik
POST-IT was supported by grants from Abbott (St. Jude Medical).
Van Belle reported receiving personal fees from Abbott (St. Jude Medical) and Philips Volcano.