Fractional Flow Reserve Derived from Computer Tomography in Asymptomatic Patients with Type 2 Diabetes and Albuminuria without Significant Coronary Artery Stenosis—A Surrogate for Coronary Microvascular Dysfunction?

Background: Type 2 diabetes mellitus (T2D) patients with albuminuria have coronary microvascular dysfunction (CMD). Fractional flow reserve assessed by coronary computed tomography angiography (FFRct) is dependent on the structure and function of the microcirculation and is likely influenced by CMD. We aimed to evaluate if asymptomatic patients with T2D who had no significant coronary artery stenosis but had been diagnosed with albuminuria had lower value of nadir FFRct compared to asymptomatic patients with T2D and no albuminuria. Methods and results: This was a cross-sectional study which compared the mean nadir FFRct values in coronary arteries in patients with T2D who had no symptoms of angina. The T2D patients were divided into two groups (albuminuria and no albuminuria) with albuminuria being defined as albumin–creatinine-ratio (ACR) ≥30 milligram per gram. The nadir FFRct values were compared between the two groups for left anterior descendent artery (FFRct-LAD), circumflex artery (FFRct-CX), and right coronary artery (FFRct-RCA) by using a two-sample Wilcoxon rank-sum (Mann–Whitney) test. Ninety-eight patients without albuminuria and 26 patients with albuminuria were included. No significant differences in mean values were detected for FFRct-CX 0.86 ± 0.07 and 0.88 ± 0.0, FFRct-RCA 0.88 ± 0.05 and 0.88 ± 0.07, or for FFRct-LAD 0.82 ± 0.07 and 0.82 ± 0.07 in patients with albuminuria and without albuminuria, respectively. Conclusion: In this observational study, we did not find that FFRct was affected by CMD. Therefore, it is not a surrogate for microvascular dysfunction in asymptomatic T2D patients with albuminuria.