Methodological Issues and Controversies in COVID-19 Coagulopathy: A Tale of Two Storms

Coagulopathy during COVID-19 infection: a brief review

The COVID-19 pandemic caused by SARS-CoV-2 continues to spread rapidly due to its virulence and ability to be transmitted by asymptomatic infected persons. If they are present, the symptoms of COVID-19 may include rhinorrhea (runny nose), headache, cough, and fever. Up to 5% of affected persons may experience more severe COVID-19 illness, including severe coagulopathy, acute respiratory distress syndrome (ARDS) characterized by respiratory failure that requires supplementary oxygen and mechanical ventilation, and multi-organ failure. Interestingly, clinical evidence has highlighted the distinction between COVID-19-associated coagulopathy (CAC) and disseminated intravascular coagulation (DIC). Patients with CAC exhibit different laboratory values than DIC patients for activated partial thromboplastin time (aPTT) and prothrombin time (PT) which may be normal or shortened, varying platelet counts, altered red blood cell morphology, unique bleeding complications, a lack of schistocytes in the peripheral blood, and no decrease in fibrinogen levels. In this review, we consider the search for 1) laboratory results that can diagnose or predict development of CAC, including serum levels of D-dimers, fibrinogen, interleukin-6 (IL-6) and the growth factor angiopoietin-2 (Ang-2), 2) mechanisms of CAC induction, and 3) novel therapeutic regimens that will successfully treat COVID-19 before development of CAC.

Incidence of Venous Thromboembolism and Effect of Anticoagulant Dosing in Hospitalized COVID-19 Patients

Background

Coronavirus disease 2019 (COVID-19) is characterized by coagulopathy and thrombotic events. We examined factors associated with development of venous thromboembolism (VTE) in COVID-19 and to discern if higher dose of anticoagulation was beneficial in these patients.

Methods

This study involves an observational study of prospectively collected data in the setting of a large community hospital in a rural setting in Northeast Georgia with COVID-19 between March 1, 2020 and February 5, 2021. Anticoagulation dose (none, standard, intermediate, and therapeutic dosages) was studied in adult patients (≥ 18 years). We constructed multivariable logistic regression model to examine the association of clinical characteristics with VTE. To examine the effect of dose of anticoagulation in preventing VTE, we used inverse probability weighted regression adjustment.

Results

Of the 4,645 patients with COVID-19, 251 (5.4%) patients were found to have VTE. Of these, 91 had pulmonary embolism, 148 had deep venous thrombosis (DVT) and 12 had both. A total of 129 of VTE cases were diagnosed at admission. Of all admissions, 12.9% did not receive any DVT prophylaxis, 70.4% received prophylactic dose, 1.3% received intermediate dose and 15.5% received therapeutic dose. Male gender (odds ratio (OR): 1.55, 95% confidence interval (CI): 1.0 - 2.4, P = 0.04) and Black race (OR: 2.0, 95% CI: 1.2 - 3.4, P = 0.01), along with higher levels of lactate dehydrogenase (LDH) and D-dimer were associated with higher odds of developing VTE. Patients receiving steroids had lower rates of VTE (3.9% vs. 8.3%, P < 0.001). Use of intermediate or therapeutic anticoagulation was not associated with lower odds of developing VTE. However, patients on therapeutic anticoagulation had lower odds of in hospital mortality when compared to standard dose (OR: 0.47, 95% CI: 0.27 - 0.80, P = 0.006).

Conclusions

In COVID-19, D-dimer and LDH can be useful in predicting VTE. Steroids appear to have some protective role in development of VTE. Therapeutic anticoagulation did not result in lower rates of VTE but was associated with in-hospital mortality.

Prophylaxis and treatment of COVID-19 related venous thromboembolism

COVID-19 pneumonia has been associated with high rates of thrombo-embolic complications, mostly venous thromboembolism (VTE), which is thought to be a combination of conventional VTE and in situ immunothrombosis in the pulmonary vascular tree. The incidence of thrombotic complications is dependent on setting (intensive care unit (ICU) versus general ward) and the threshold for performing diagnostic tests (screening versus diagnostic algorithms triggered by symptoms). Since these thrombotic complications are associated with in-hospital mortality, all current guidelines and consensus papers propose pharmacological thromboprophylaxis in all hospitalized patients with COVID-19. Several trials are ongoing to study the optimal intensity of anticoagulation for this purpose. As for the management of thrombotic complications, treatment regimens from non-COVID-19 guidelines can be adapted, with choice of anticoagulant drug class dependent on the situation. Parenteral anticoagulation is preferred for patients on ICUs or with impending clinical deterioration, while oral treatment can be started in stable patients. This review describes current knowledge on incidence and pathophysiology of COVID-19 associated VTE and provides an overview of guideline recommendations on thromboprophylaxis and treatment of established VTE in COVID-19 patients.