Endothelial dysfunction in diabetic patients with abnormal myocardial perfusion in the absence of epicardial obstructive coronary artery disease.
In patients with diabetes mellitus, myocardial perfusion defects are often observed in the absence of obstructive epicardial coronary artery disease (CAD), thereby presenting a diagnostic problem. We hypothesized that these perfusion abnormalities may be explained by endothelial dysfunction or occult coronary atherosclerosis.


METHODS
Prospectively, 130 asymptomatic patients with diabetes mellitus underwent cardiovascular screening by coronary artery calcium (CAC) scoring, multislice CT coronary angiography, and myocardial perfusion imaging by SPECT. Multislice CT images were evaluated for the presence of obstructive epicardial CAD (>or=50% luminal narrowing). To quantify abnormal myocardial perfusion on SPECT images, we determined the summed stress score for each patient. The presence of abnormal myocardial perfusion was defined as a summed stress score of 3 or more. In addition, flow-mediated dilatation of the brachial artery, a marker of endothelial function, was determined using ultrasonography.


RESULTS
In 35 patients (27%), obstructive epicardial CAD was observed on multislice CT, and these patients were excluded from further analysis. In the remaining 95 patients, abnormal myocardial perfusion was observed in 30 (32%) of patients. Flow-mediated dilatation was significantly lower in patients with abnormal myocardial perfusion (3.6% +/- 2.4%) than in those with normal myocardial perfusion (6.4% +/- 2.6%) (P < 0.001). Importantly, flow-mediated dilatation remained a significant predictor of the extent of abnormal myocardial perfusion after correction for cardiovascular risk factors and CAC score (P < 0.001). In contrast, no association was observed between nonobstructive plaque burden as reflected by CAC scores and extent of abnormal myocardial perfusion.


CONCLUSIONS
In patients with diabetes mellitus, myocardial perfusion abnormalities in the absence of obstructive epicardial CAD are associated with endothelial dysfunction.
Djaberi
Roxana
R
Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
Roodt
Jos op 't
Jo
Schuijf
Joanne D
JD
Rabelink
Ton J
TJ
de Koning
Eelco J
EJ
Pereira
Alberto M
AM
Stokkel
Marcel P
MP
Smit
Jan W
JW
Bax
Jeroen J
JJ
Jukema
J Wouter
JW
D002118:Calcium / Q000378:metabolism; D017023:Coronary Angiography; D003324:Coronary Artery Disease; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D048909:Diabetes Complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon
D002118:Calcium