Correlation between carotid artery distensibility and serum vascular endothelial growth factor concentrations in type 1 diabetic subjects and nondiabetic subjects

Abstract

The relationships between serum vascular endothelial growth factor (VEGF) concentrations and vessel wall ultrasonic characteristics in type 1 diabetic and nondiabetic subjects were assessed. Serum VEGF concentration was measured, and ultrasound imaging and blood pressure recordings were performed in 41 type 1 diabetic subjects (hemoglobin A 1c [HbA 1c], 7.63 [1.17%]; duration of diabetes, 12 (0 to 23) years), and 50 nondiabetic subjects. Change in carotid artery luminal diameter during the cardiac cycle was measured using M-mode ultrasound, from which percentage increase in carotid artery luminal diameter was calculated; the carotid artery distensibility index was calculated as the ratio of percentage increase in carotid artery luminal diameter and pulse pressure. Serum VEGF concentration was higher in the diabetic subjects (217 [135 to 336] v 137 [80 to 237] pg/mL; P = .009). The percentage increase in carotid luminal diameter during the cardiac cycle was not significantly different between the 2 groups (12.9 [10.2 to 15.7] v 13.0 [10.6 to 15.0%]; P = .270) despite significantly greater pulse pressure in the type 1 diabetic group (55 [45 to 71] v 46 [41 to 51] mm Hg; P = .0003). The distensibility index was therefore lower in the diabetic subjects (0.24 [0.10] v 0.28 [0.08%]/mm Hg; P = .031). There was a significant negative correlation between serum VEGF concentrations and mean percentage increase in carotid luminal diameter during the cardiac cycle in the diabetic group ( r = [minus ].36, P = .021) and in the nondiabetic group ( r = [minus ].28, P = .047). This negative correlation could be strengthened by relating mean percentage increase in luminal diameter to pulse pressure to give the distensibility index. Therefore, serum VEGF concentrations correlated strongly and inversely with the distensibility index in the diabetic group ( r = [minus ].49, P = .001), in the nondiabetic group ( r = [minus ].29, P = .041), and in both groups analyzed together ( r = [minus ].42, P [lt ] .0001). Vessel wall distensibility may be an important determinant of serum VEGF concentrations in both diabetic and nondiabetic populations and may underlie the previously observed association between blood pressure and serum VEGF concentrations. The pathophysiologic relevance of these findings remains to be elucidated.