Evaluation of systemic microvascular reactivity in adults with congenital heart disease

Objective Adults with congenital heart disease share some features with those with chronic heart failure. Although microvascular endothelial dysfunction has been described in chronic heart failure, evaluation of the microcirculation in adults with congenital heart disease is lacking. The present study aimed to investigate systemic microvascular reactivity in adults with congenital heart disease. Interventions The patients initially underwent cardiopulmonary exercise testing. Then, the cutaneous microvascular reactivity was evaluated in these patients using a laser speckle contrast imaging system coupled with skin iontophoresis of endothelial-dependent (acetylcholine) or -independent (sodium nitroprusside) vasodilators and postocclusive reactive hyperemia (PORH) and compared with healthy controls matched for age and sex. Results Thirty-one patients and 29 healthy controls were evaluated. The basal microvascular flow (P < .0001) and area under the curve in response to acetylcholine (P < .0001) were higher in the patients than in the healthy volunteers. The increase in cutaneous vascular conductance in response to sodium nitroprusside was reduced in the patients compared to the healthy volunteers (P = .0031). No difference in the microvascular response was observed during postocclusive reactive hyperemia. The basal microvascular flow of patients with peak oxygen consumption below 16.0 mL kg-1 min-1 was superior to that of patients with values greater than 16.0 mL kg-1 min-1 (P = .0046). Conclusions Adults with congenital heart disease present a higher baseline cutaneous microvascular blood flow than healthy controls and do not present systemic microvascular endothelial dysfunction. Nevertheless, endothelium-independent microvascular reactivity is blunted, suggesting an altered vascular smooth muscle response or vascular structural alterations. Finally, patients with a lower functional capacity presented a greater microvascular basal blood flow than subjects with a higher functional capacity.