Influence of diabetes mellitus on the invasive assessment of myocardial ischemia in patients with coronary artery disease.

Abstract

Current guidelines recommend physiological evaluation of borderline coronary artery stenoses using hyperemic (fractional flow reserve [FFR]) and nonhyperemic (instantaneous wave‑free ratio [iFR] and resting full‑cycle ratio [RFR]) methods. However, comorbidities, such as diabetes mellitus (DM), may influence the results of the assessment. We sought to investigate the impact of DM and insulin treatment on the discordance between FFR and iFR/RFR. A total of 417 intermediate stenoses in 381 patients underwent FFR and iFR/RFR assessment. FFR lower than or equal to 0.8 and iFR/RFR lower than or equal to 0.89 indicated significant ischemia. The patients were categorized based on DM diagnosis and insulin treatment status. Of the 381 patients, 154 (40.4%) had DM. Among these, 58 patients (37.7%) received insulin treatment. Diabetic patients had higher body mass index and glycated hemoglobin levels, and lower ejection fraction. FFR and iFR/RFR analyses were conducted in 417 vessels with available measurements for both tests. A good correlation between FFR and iFR/RFR was confirmed in both diabetic (R = 0.77) and nondiabetic (R = 0.74) patients. Discordance between FFR and iFR/RFR occurred in approximately 20% of cases, and the frequency of discordance was not affected by the diabetic status. However, insulin‑treated DM was independently associated with a higher risk of negative FFR and positive iFR/RFR discordance (odds ratio, 4.61; 95% CI, 1.38-15.4; P = 0.01). Also, the optimal cutoff value for FFR identifying significant ischemia in DM patients treated with insulin was higher (0.84) than the generally recommended value. The rate of FFR and iFR/FFR discordance was similar regardless of the diabetes status, and insulin‑treated DM was associated with an increased risk of negative FFR and positive iFR/RFR discordance.