Purpose  

To demonstrate the presence of endothelial dysfunction (ED) in asymptomatic patients with type 2 diabetes mellitus (DM) by using ¹³N-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 (%ΔMBF) 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 ¹³N-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 %ΔMBF was 20 ± 34% vs. 55 ± 37% (p = 0.002). Rest MBF and CPT MBF were normalized to the rate pressure product (RPP). EDVI′ and %ΔMBF′ 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 %ΔMBF′ 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 ¹³N-ammonia–PET.