Prognostic Impact of Diabetes Mellitus and Index of Microcirculatory Resistance in Patients Undergoing Fractional Flow Reserve-Guided Revascularization

Abstract

Background: The prognostic impact of diabetes mellitus (DM) with or without coronary microvascular dysfunction (CMD) in patients undergoing fractional flow reserve (FFR)-guided revascularization has not been clarified. We sought to investigate the clinical outcomes of patients undergoing FFR-guided revascularization according to the existence of DM and CMD.

Methods: A total of 283 patients with available FFR data as well as index of microcirculatory resistance (IMR) were selected from the 3 V FFR-FRIENDS study. CMD was defined as an IMR ≥25U. Patients were grouped according to the presence of DM and CMD into group A (DM-, CMD-), group B (DM-, CMD+), group C (DM+, CMD-), and group D (DM+, CMD+). The primary outcome was a major adverse cardiac event (MACE, a composite of myocardial infarction, ischemia-driven revascularization, and cardiac death) at 2 years.

Results: DM patients displayed a notably higher risk of MACEs in comparison with non-DM patients (HR 4.88, 95% CI 1.54–15.48, p = 0.003). MACEs at 2 years among the four groups were 2.2%, 2.0%, 7.0%, and 18.5%, respectively. Group D exhibited a significantly higher risk of MACEs as compared to group A (HR 8.98, 95% CI 2.15–37.41, p = 0.003). Multivariable regression analysis showed that the presence of DM and CMD was an independent predictor of a 2-year MACE (HR 11.24, 95% CI 2.53–49.88, p = 0.002), and integrating CMD into a model with DM increased discriminant ability (C-index 0.683 vs. 0.710, p = 0.010, integrated discrimination improvement 0.015, p = 0.040).

Conclusion: Among the patients undergoing FFR-guided revascularization, those with DM and CMD were correlated with an augmented risk of MACEs. Integration of CMD improved risk stratification in predicting the occurrence of a MACE.