Effect of Hyperglycemia on Myocardial Perfusion in Diabetic Porcine Models and Humans.

BACKGROUND: Diabetes mellitus (DM) causes macro- and microvasculopathy, but data on cardiac microvascular changes in large animals are scarce. We sought to determine the effect of DM on macro- and microvascular changes in diabetic pigs and humans.

METHODS: Eight domestic pigs (4 with type I diabetes and 4 controls) underwent coronary angiography with optical coherence tomography (OCT; at baseline and 1 and 2 months), coronary computed tomography angiography, cardiac magnet resonance (CMR) imaging, and histologic examination.

RESULTS: The diabetic pigs had more irregular capillaries with acellular capillaries and a smaller capillary diameter (11.7 ± 0.33 μm vs. 13.5 ± 0.53 μm; P < 0.001) than those of the control pigs. The OCT showed no significant epicardial stenosis in either group; however diabetic pigs had a greater intima-media thickness. CMR results showed that diabetic pigs had a lower relative upslope at rest (31.3 ± 5.9 vs. 37.9 ± 8.1; P = 0.011) and during stress (18.0 ± 3.0 vs. 21.6 ± 2.8; P = 0.007) than the control pigs, implying decreased myocardial perfusion. Among the 79 patients with ST elevation myocardial infarction, 25 had diabetes and they had lower myocardial perfusion on CMR as well.

CONCLUSION: DM causes microvascular remodeling and a decrease in myocardial perfusion in large animals at a very early stage of the disease course. Early and effective interventions are necessary to interrupt the progression of vascular complications in diabetic patients.