Relationship between cardiac microvascular dysfunction measured with 82Rubidium-PET and albuminuria in patients with diabetes mellitus

Background: Albuminuria is of one the strongest predictors of cardiovascular disease (CVD) in diabetes. Diabetes is associated with cardiac microvascular dysfunction (CMD), a powerful, independent prognostic factor for cardiac mortality. The aim of this study was to evaluate the relationship between CMD and microvascular complications in patients without known CVD. I Methods: In this monocentric study, myocardial flow reserve (MFR) was measured with cardiac (82)Rubidium positron emission tomography (Rb-PET) in 311 patients referred to nuclear medicine department of Bichat University Hospital I for screening of coronary artery disease from 2012 to 2014. Patients with hemodynamically relevant stenosis on coro-nary angiography or myocardial ischemia on Rb-PET were excluded. Among patients with diabetes, MFR values were [compared according to the presence of retinopathy and albuminuria. Results: Overall, 175 patients (118 with type 2 diabetes) were included. MFR was significantly lower in patients with diabetes compared with those without diabetes (2.6 +/- 1.1 vs. 3.3 +/- 1.7; p < 0.005). In patients with diabetes, MFR I decreased progressively in relation to albumin urinary excretion (normoalbuminuria: 2.9 +/- 1.1, microalbuminuria: 2.3 +/- 1.0, macroalbuminuria: 1.8 +/- 0.7; p < 0.0001). MFR was not significantly different in patients with vs. without retinopathy (2.4 +/- 1.0 vs. 2.7 +/- 1.1, p = 0.07). Microalbuminuria and macroalbuminuria remained strongly associated with impaired MFR after multiple adjustments [odds ratio 2.6 (95% CI 1.1-8.4) and 5.3 (95% CI 1.2-44.7), respectively]. This association was confirmed when analyses were restricted to patients with low levels of coronary calcifications on computed tomography. Conclusions: Impaired MFR was more frequent in patients with diabetes and was strongly associated with the degree of albuminuria suggesting that CMD and albuminuria might share common mechanisms.