Hand exercise test for the assessment of endothelium-dependent vasodilatation in subjects with type 1 diabetes

At present, endothelial dysfunction is best assessed in vivo with measurement of flow-mediated dilatation (FMD) with Doppler ultrasound scanning. This test, however, does not account for the subject's age and is uncomfortable for patients. The aim of the study was to compare a new test for endothelium function assessment using hand exercise load.

The study group comprised 31 male patients with type 1 diabetes and 72 healthy men as controls. The subjects in both groups were subdivided into three age groups: 18-30 (subgroup A), 31-45 (subgroup B), and 46-60 (subgroup C) years. FMD of the brachial artery with induction of hand ischemia was conducted in all the subjects. Afterwards, an originally designed test using standardized hand exercise with the use of a training device was performed.

In the youngest group of type 1 diabetes patients the effect of hand ischemia on brachial artery diameter was greater than in the two older age subgroups: baseline artery diameter increased by 0.23 +/- 0.11 mm (5.7%), 0.19 +/- 0.09 mm (4.3%), and 0.13 +/- 0.02 mm (2.8%), respectively (P < 0.01). In the hand exercise test, artery diameter increased in the youngest subjects by 0.39 +/- 0.11 mm (9.5%) and in the two older groups by 0.26 +/- 0.07 mm (5.6%) and 0.18 +/- 0.09 mm (4.5%) (P < 0.05), respectively. In subgroups A, B and C, vasodilation after hand exercise test was greater by 67%, 30%, and 32% (P < 0.01), respectively, compared with the effect of the ischemic test. In the controls similar effects and relationship between ischemic and hand exercise tests were noted, however, with a smaller difference between the two tests.

The hand exercise test results in a greater difference in vessel diameter before and after the test stimulus, which might substantially improve its feasibility. The hand exercise test could be a useful alternative tool for endothelial function assessment, especially in type 1 diabetes subjects.