Evidence of intact resting but exercise-induced vascular impairment in congenital heart disease

Abstract

Young patients with congenital heart disease (CHD) often display impaired peripheral vascular function, yet evidence of the effects of exercise is limited. This study tested the hypothesis that 1) brachial artery reactivity and forearm microvascular function would be impaired in young patients with CHD and 2) acute isometric handgrip (IHG) exercise would improve brachial artery reactivity and forearm microvascular function in young patients with CHD. Brachial artery flow-mediated dilation (FMD) and the reactive hyperemic response [mean brachial artery blood flow area under the curve (AUC)] were tested in young patients with CHD (n = 19; 13 (4) yr; 12 male, 7 female) and healthy age-matched controls (n = 21; 13 (4) yr, 12 male, 9 female) pre- and postacute IHG exercise. Pre-IHG exercise brachial artery FMD [4.0 (3.1) vs. 5.8 (3.9)%, P = 0.348] and reactive hyperemia [139 (69) vs. 167 (82) AUC, P = 0.449] were not different between controls and young patients with CHD, respectively. In controls, acute IHG exercise increased FMD [4.0 (3.1) to 5.9 (2.5)%, P = 0.016] and reactive hyperemia [139 (69) to 175 (75) AUC, P = 0.017]. However, in young patients with CHD, acute IHG exercise only increased reactive hyperemia [167 (82) to 187 (65) AUC, P = 0.017], but not FMD [5.8 (3.9) vs. 4.9 (2.9)%, P = 0.426]. Endothelial-dependent vasodilation is intact in young patients with CHD, but acute exercise may alter local regulatory mechanisms such that endothelial-dependent vasodilation fails to augment. Microvascular function is unaltered with CHD.NEW & NOTEWORTHY Although young healthy control participants realize augmented brachial artery flow-mediated dilation following acute isometric handgrip exercise, young patients with congenital heart disease (CHD) fail to do so. Forearm microvascular function remains intact in congenital heart disease and is enhanced similarly to control participants following acute isometric handgrip exercise. Acute exercise may alter local regulatory mechanisms such that conduit artery endothelial-dependent vasodilation is not augmented, providing evidence of stress-induced vascular impairment in young patients with CHD.

Keywords: blood flow; brachial artery endothelial function; children; flow mediated dilation; young adults.