Non-invasive assessment of vascular function: Paradoxical vascular response to glucose in coronary heart disease

Background: The vascular effects of insulin are nitric oxide-dependent, and independent of insulin's effect on glucose metabolism. Glucose, administered intravenously (iv.) as in the iv. glucose tolerance test (IVGTT), causes a physiological hyperinsulinaemia. We hypothesised that the this insulin response leads to forearm blood flow (FBF) changes in healthy individuals, and that such a response might be altered in patients with coronary heart disease (CHD). Methods: 10 healthy men and 13 men with angiographically proven CHD [aged 65.5±2.4 yrs, mean±SEM] underwent an IVGTT with simultaneous measurement of FBF (mercury-in-silastic venous occlusion plethysmography) at 28 time points over 3 hrs following iv. glucose administration. Results: In healthy controls, FBF increased to 31.7% above baseline at 7 mins and remained above baseline up to 180 mins after i.v. glucose. Significant group differences emerged in the % change in FBF from baseline at 180 mins (controls: +112.8±24.9%; CHD patients: -25.8±7.3%, p