COVID-19-related dynamic coagulation disturbances and anticoagulation strategies using conventional D-dimer and point-of-care Sonoclot tests: a prospective cohort study.

objectivesCoagulation changes associated with COVID-19 suggest the presence of a hypercoagulable state with pulmonary microthrombosis and thromboembolic complications. We assessed the dynamic association of COVID-19-related coagulation abnormalities with respiratory failure and mortality.

designSingle-centre, prospective cohort study with descriptive analysis and logistic regression.

settingTertiary care hospital, North India.

participantsPatients with COVID-19 pneumonia requiring intensive care unit (ICU) admission between August 2020 and November 2020. PRIMARY AND SECONDARY OUTCOME MEASURES: We compared the coagulation abnormalities using standard coagulation tests like prothrombin time, D-dimer, platelet count, etc and point-of-care global coagulation test, Sonoclot (glass beaded(gb) and heparinase-treated(h)). Incidence of thromboembolic or bleeding events and presence of endogenous heparinoids were assessed. Cox proportional Hazards test was used to assess the predictors of 28-day mortality. MEASUREMENT: All patients underwent Sonoclot (glass beaded) test at admission apart from the routine investigations. In patients at risk of thromboembolic or bleeding phenomena, paired tests were performed at day 1 and 3 with Sonoclot. Activated clotting time (ACT) <110 s and peak amplitude >75 units were used as the cut-off for hypercoagulable state. Presence of heparin-like effect (HLE) was defined by a correction of ACT ≥40 s in h-Sonoclot.

resultsOf 215 patients admitted to ICU, we included 74 treatment naive subjects. A procoagulant profile was seen in 45.5% (n=5), 32.4% (n=11) and 20.7% (n=6) in low-flow, high-flow and invasive ventilation groups. Paired Sonoclot assays in a subgroup of 33 patients demonstrated the presence of HLE in 17 (51.5%) and 20 (62.5%) at day 1 and 3, respectively. HLE (day 1) was noted in 59% of those who bled during the disease course. Mortality was observed only in the invasive ventilation group (16, 55.2%) with overall mortality of 21.6%. HLE predicted the need for mechanical ventilation (HR 1.2 CI 1.04 to 1.4 p=0.00). On multivariate analysis, the presence of HLE (HR 1.01; CI 1.006 to 1.030; p=0.025), increased C reactive protein (HR 1.040; CI 1.020 to 1.090; p=0.014), decreased platelet function (HR 0.901; CI 0.702 to 1.100 p=0.045) predicted mortality at 28days.

conclusionHLE contributed to hypocoagulable effect and associated with the need for invasive ventilation and mortality in patients with severe COVID-19 pneumonia.

trial registrationNCT04668404; ClinicalTrials.gov.in. Available from https://clinicaltrials.gov/ct2/show/NCT04668404.