Alexa Provancha, University of Utah
Exercise and Sport Science
Impaired endothelium-dependent vasodilation has been associated with various cardiovascular diseases, including heart failure, is linked to oxidative stress, and persists despite heart transplantation (HTx). PURPOSE: This study aimed to determine if changes in vascular function following HTx can be assessed using incremental handgrip (HG) exercises to induce nitric oxide-dependent vasodilation of the brachial artery. Furthermore, the efficacy of an acute oral antioxidant cocktail (AOC) to reduce oxidative stress and improve vascular function in this population will be assessed. METHODS: 31 HTx recipients (14 years post-HTx) and 10 healthy age-matched controls were given either and AOC (Vitamin C, E, and alpha-lipoic acid) or placebo (PL; randomized for the subjects’ two visits. Measurements of the brachial arterial blood velocity and vessel diameter were performed during three absolute workloads (4, 8, and 12 kg) of HG exercise using ultrasound Doppler. RESULTS: Maximal vasodilation during PL HG exercise was not different between the controls (8.2 ± 1.5%), and recent (< 3 years post) HTx group (8.5 ± 1.2%), but the 5-10 years post-HTx groups had a tendency to be lower (6.5 ± 1.9%). The > 14 years post-HTx group recipients (5.2 ± 1.9%) were significantly attenuated compared to both the controls and the recent (< 3 years post) HTx recipients. CONCLUSION: The study supports the use of HG exercise as an assessment of vascular function in a patient population with known cardiovascular risk. Additionally, these results suggest that vascular function is similar between controls and early HTx recipients but declines as time passes following surgery despite normalized cardiac function.