ABSTRACT
BACKGROUND: Elevated estimated blood viscosity (EBV), derived from hematocrit and globulins, is associated with thrombotic complications, organ failure, and higher mortality in COVID-19 patients. Although informative, EBV does not account for cellular interactions or fibrinogen. OBJECTIVE: Investigate whether patients with acute and recent COVID-19 have altered whole blood viscosity (WBV) when measured at both high and low shear rates using in vitro blood samples from patients. METHODS: Cross-sectional study of 58 patients: 15 in the intensive care unit with acute COVID-19, 32 convalescent (9â<â8weeks [W] from acute infection, 23â>â8âW), and 11 controls without COVID-19. WBV was measured at high (300âs-1) and low (5âs-1) shear rates (HSR, LSR) using a scanning capillary viscometer.RESULTSAcute and convalescent patientsâ<â8âW had mean WBV at LSR (16.0 centipoise [cP] and 15.1 cP) and HSR (5.1 cP and 4.7 cP). Mean WBV of convalescentâ>â8âW and control patients were 12.3 cP and 13.0 cP at LSR, and 4.1 cP and 4.2 cP at HSR. Acute andâ<â8âW patients had significantly higher WBV at both HSR and LSR compared to patientsâ>â8âW (all p≤0.01). No significant differences in WBV were observed between acute andâ<â8âW patients, or between patientsâ>â8âW and controls. CONCLUSIONS: Hyperviscosity provides a possible explanation for thrombotic risk in acute and convalescent (<â8âW) patients. These findings have important implications for thromboprophylaxis.
Subject(s)
COVID-19 , Thrombophilia , Thrombosis , Venous Thromboembolism , Humans , Cross-Sectional Studies , Anticoagulants , Venous Thromboembolism/complications , Blood Viscosity , Thrombosis/etiologyABSTRACT
BACKGROUND: Coronavirus disease-2019 (COVID-19) is characterized by a dysfunctional immune response and abnormal blood rheology that contribute to endothelial dysfunction and thrombotic complications. Whole blood viscosity (WBV) is a clinically validated measure of blood rheology and an established predictor of cardiovascular risk. We hypothesize that increased WBV is associated with mortality among patients hospitalized with COVID-19. OBJECTIVES: This study sought to determine the association between estimated BV (eBV) and mortality among hospitalized COVID-19 patients. METHODS: The study population included 5,621 hospitalized COVID-19 patients at the Mount Sinai Health System from February 27, 2020, to November 27, 2021. eBV was calculated using the Walburn-Schneck model. Multivariate Cox proportional hazards models were used to evaluate the association between eBV and mortality. Considered covariates included age, sex, race, cardiovascular and metabolic comorbidities, in-house pharmacotherapy, and baseline inflammatory biomarkers. RESULTS: Estimated high-shear BV (eHSBV) and estimated low-shear BV were associated with increased in-hospital mortality. One-centipoise increases in eHSBV and estimated low-shear BV were associated with a 36.0% and 7.0% increase in death, respectively (P < 0.001). Compared with participants in the lowest quartile of eHSBV, those in the highest quartile of eHSBV had higher mortality (adjusted HR: 1.53; 95% CI: 1.27-1.84). The association was consistent among multiple subgroups, notably among patients without any comorbidities (adjusted HR: 1.69; 95% CI: 1.28-2.22). CONCLUSIONS: Among hospitalized COVID-19 patients, increased eBV is significantly associated with higher mortality. This suggests that eBV can prognosticate patient outcomes in earlier stages of COVID-19, and that future therapeutics aimed at reducing WBV should be evaluated.