Endothelial Dysfunction in Recently Diagnosed Type 2 Diabetic Patients Evaluated by PET

Purpose: To demonstrate the presence of endothelial dysfunction (ED) in asymptomatic patients with type 2 diabetes mellitus (DM) by using N-13-ammonia-positron emission tomography (PET). PET can identify ED by quantifying myocardial blood flow (MBF) during rest, cold pressor test (CPT), and pharmacologic stress. The endothelial-dependent vasodilation index (EDVI), myocardial flow reserve (MFR), and the percentage of the change between rest and CPT (%Delta MBF) are markers of endothelial function. Procedures: Thirty-nine subjects were studied (19 women and 20 men); 22 recently diagnosed type 2 diabetic patients and 17 healthy controls (HC). A three-phase N-13-ammonia-PET was performed. Results: Mean EDVI was 1.208 +/- 0.34 vs. 1.55 +/- 0.37 (diabetic vs. HC group, respectively) (p=0.002), MFR was 2.803 +/- 1.39 vs. 3.27 +/- 0.72 (p=NS), and the %Delta MBF was 20 +/- 34% vs. 55 +/- 37% (p=0.002). Rest MBF and CPT MBF were normalized to the rate pressure product (RPP). EDVI' and %Delta MBF' were calculated using the corrected values for the RPP. Mean EDVI' was (0.864 +/- 0.250 vs. 1.110 +/- 0.238, p=0.004) and mean %Delta MBF' was (-8.2 +/- 14.7% vs. 4.5 +/- 12.1%, p=0.005). Conclusions: Asymptomatic, recently diagnosed type 2 diabetes patients present ED that can be quantified by N-13-ammonia-PET.