Early impairment of large artery structure and function in Type I diabetesmellitus

Aims/hypothesis. Diabetes mellitus is associated with an increased incidenc e of atherosclerosis. How early functional and structural alterations of la rge arteries that may preceed atherosclerosis occur in the course of this d isease has, however, never been conclusively documented. Methods. We evaluated arterial wall distensibility in the radial artery, co mmon carotid artery and abdominal aorta in 133 patients (aged 35.4 +/- 0.9 years, means +/- SEM) with Type I (insulin-dependent) diabetes mellitus and no macrovascular complications. Arterial distensibility was derived from c ontinuous measurements of arterial diameter through echotracking techniques and use of either the Langewouters (radial artery) or the Reneman (carotid artery and aorta) formula. The same echotracking techniques enabled us to obtain radial artery and carotid artery wall thickness. Data were compared with those from 70 age-matched normotensive control subjects. Results. In diabetic patients arterial distensibility was consistently less (p < 0.01) than in control subjects, the reduction averaging 26%, 14% and 25% for the radial artery, carotid artery and aorta, respectively. This was accompanied by an increase (p < 0.01) in both radial and carotid artery wa ll thickness. The changes were more pronounced in patients with microalbumi nuria, retinopathy or neuropathy or both. They were evident also in those w ithout microvascular complications. This was the case also when subjects in whom diabetes was associated with hypertension (n = 30) were excluded from data analysis. Carotid and aortic wall abnormalities showed a relation wit h the duration of disease and blood pressure whereas radial artery abnormal ities showed a relation with glycated haemoglobin. Conclusion/interpretation. Type I diabetes is characterised by diffuse arte rial wall stiffening and thickening which progress with the severity of the disease but can clearly be seen also in the absence of any diabetic-relate d complication. This suggests that in diabetes stiffening and thickening ar e an early marker of vascular damage.