Endothelial dysfunction in type 2 diabetic patients with normal coronary arteries A digital reactive hyperemia study

Background: To assess endothelial function (EF) in type 2 diabetic patients with angiographically normal coronaries compared to diabetic patients with obstructive coronary artery disease (CAD) and to non-diabetic patients, with and without CAD. Methods: One hundred eighty-three patients undergoing coronary angiography were divided in: group 1 with diabetes mellitus (DM) and CAD (n=58); group 2 with DM without CAD (n=58); group 3 with CAD without DM (n=31) and group 4 without CAD and DM (n=36). EF was assessed by reactive hyperemia index (RHI) using a fingertip peripheral arterial tonometry and compared to values obtained in 20 healthy volunteers. Results: RHI was significantly lower in patients with DM compared to patients without DM (1.69 +/- 0.38 vs 1.84 +/- 0.44; p=0.019). RHI was comparable among groups 1, 2 and 3, each value being significantly lower compared to group 4 (2 +/- 0.44; p<0.001 vs group 1; p<0.005 vs group 2; p<0.002 vs group 3). At multivariate analysis DM and CAD were significant predictors of endothelial dysfunction (ED) (OR=2.29; p=0.012; OR=2.76; p=0.001, respectively), whereas diabetic patients (n=116) CAD and glycated haemoglobin (HbA1c) were independent significant predictors of ED (OR=3.05; p=0.009; OR=1.96; p=0.004, respectively). Diabetic patients with ED (n=67) had higher levels of HbA1c than diabetic patients with normal endothelial function (7.35 +/- 0.97 vs 6.87 +/- 0.90; p=0.008) and RHI inversely correlated to HbA1c (p=0.02; r=-0.210). Conclusions: Diabetic patients with and without CAD show significantly impaired peripheral vascular function compared to non-diabetic patients without CAD. ED in diabetic patients without CAD is comparable to that of patients with CAD but without DM. HbA1c is a weak independent predictor of ED. (C) 2011 Elsevier Ireland Ltd. All rights reserved.