Abstract
BACKGROUND: A significant proportion of patients with coronavirus disease 19 (COVID-19) suffer from excessive coagulation activation and coagulopathy which is associated with an increased risk of venous and arterial thromboembolism and adverse outcome. Our study investigates coagulation markers and the incidence of thromboembolic events in COVID-19 patients receiving recommended anticoagulation strategies. METHODS: In a retrospective single-center analysis at the University Hospital Zurich, Switzerland, we investigated 31 adult COVID-19 patients between April 6th and May 13th, 2020 and with at least one laboratory assessment of the coagulation markers prothrombin time/Quick, thrombin time, fibrinogen and D-dimers. For antithrombotic prophylaxis low-molecular-weight-heparin or unfractionated heparin was administered and two patients with heparin-induced thrombocytopenia received argatroban. RESULTS: We analyzed 31 patients (68% male, mean age 60± SD 15 years). 22 (71%) of these required intensive care unit treatment, 5 (16%) were hospitalized in a ward, and 4 (13%) were outpatients. Mean fibrinogen levels were markedly elevated to 6.4± SD 1.8g/l, with a peak in the third week of the disease and no significant decrease over time. D-dimers were elevated to a mean value of 5.1±4.4mg/l with peak levels of 6.8±5.3mg/l in the fourth week of disease, and a subsequent decrease. Platelet count (308±136G/l) and PT/Quick (85±22%) showed no significant changes over time. Sensitivity analyses for patients treated in the ICU showed that D-dimer levels were higher in this group. The results of other sensitivity analyses were comparable. Thromboembolic events were diagnosed in 4 (13%) patients and 5 (16%) patients died during the observation period. CONCLUSION: We find coagulation alterations in COVID-19 patients indicating significant hypercoagulability. These alterations are visible despite antithrombotic treatment, and peak around week 3-4 of the disease.