Blunted peripheral but not cerebral vasodilator function in young otherwise healthy adults with persistent symptoms following COVID-19.

Recent findings suggest that COVID-19 causes vascular dysfunction during the acute phase of the illness in otherwise healthy young adults. To date, no studies have investigated the longer-term effects of COVID-19 on vascular function. Herein, we hypothesized that young, otherwise healthy adults who are past the acute phase of COVID-19 would exhibit blunted peripheral (brachial artery flow-mediated dilation (FMD) and reactive hyperemia) and cerebral vasodilator function (cerebral vasomotor reactivity to hypercapnia; CVMR) and increased central arterial stiffness. Sixteen young adults who were at least 4 weeks past a COVID-19 diagnosis and 12 controls who never had COVID-19 were studied. Eight COVID subjects were symptomatic (SYM) and 8 were asymptomatic (ASYM) at the time of testing. FMD and reactive hyperemia were not different between COVID and Control groups. However, FMD was lower in SYM (3.8 ± 0.6%) compared to ASYM (6.8 ± 0.9%; P = 0.007) and Control (6.8 ± 0.6%; P = 0.003) with no difference between ASYM and Control. Similarly, peak blood velocity following cuff release was lower in SYM (47 ± 8 cm/s) compared to ASYM (64 ± 19 cm/s; P = 0.025) and Control (61 ± 14 cm/s; P = 0.036). CVMR and arterial stiffness were not different between any groups. In summary, peripheral macro- and microvascular function, but not cerebral vascular function or central arterial stiffness were blunted in young adults symptomatic beyond the acute phase of COVID-19. In contrast, those who were asymptomatic had similar vascular function compared to controls who never had COVID.