ABSTRACT
Vascular dysfunction and inflammation are precursors to cardiovascular disease (CVD). Notably, young adults who were symptomatic from COVID-19 during the acute phase of illness (within 4 weeks from diagnosis) have shown to exhibit peripheral vascular dysfunction. Importantly, many young adults report persistent symptoms from COVID-19 for several months, including cognitive difficulties. However, it remains unknown whether vascular dysfunction persists beyond the acute phase of COVID-19 in symptomatic young adults. We tested the hypothesis that peripheral and cerebral vascular function would be blunted in symptomatic (SYM) young adults who are beyond 4 weeks from a COVID-19 diagnosis, compared to asymptomatic adults (ASYM). Since COVID-19 causes inflammation that may negatively impact vascular function, we also hypothesized that serum hsCRP would be elevated in SYM compared to ASYM. We studied 15 otherwise healthy adults (age = 23 ± 1 years;mean ± SE) with a positive lab diagnosis of COVID-19. Eight were SYM (14 ± 1 weeks from diagnosis) while seven were ASYM (13 ± 2 weeks from diagnosis) at time of testing. Brachial artery flow-mediated dilation (FMD;duplex Doppler ultrasound) was performed, and macroand microvascular function were quantified as FMD% and peak blood velocity after cuff release, respectively. Cerebral vasomotor reactivity (CVMR) was quantified as percent increase in middle cerebral artery blood velocity (transcranial Doppler ultrasound) to rebreathing induced hypercapnia. Serum hsCRP level was measured. FMD was lower in SYM (3.81 ± 0.60%) compared to ASYM (7.10 ± 0.94%, P = 0.010). Likewise, peak blood velocity after cuff release was lower in SYM (47 ± 3 cm/s vs. ASYM: 65 ± 8 cm/s, P = 0.037). However, CVMR was not different between the two groups (P = 0.91). Serum hsCRP was higher in SYM (3.4 ± 1.0 mg/L vs. ASYM: 0.7 ± 0.1 mg/L, P = 0.036). These preliminary results indicate that peripheral macro-and microvascular function remain blunted beyond the acute phase in young adults with persistent symptoms from COVID-19, whereas cerebral vascular function appears unaffected. The extent to which this sustained vascular impairment and elevated hsCRP contributes to increased CVD risk in these otherwise healthy young adults remains to be determined.