Abnormal Clotting
Charnicia Huggins, PharmD
Various researchers have noted abnormal blood clotting among patients diagnosed with COVID-19. This was first reported by scientists in Wuhan, China during the early days of the pandemic. They found that increased D-dimer levels, a marker of blood clots, may be linked to poorer prognosis among adult inpatients with COVID-19. Later studies also revealed high D-dimer levels and varying incidences of venous thromboembolism in patients with severe disease.
On the surface, health care providers saw that patients quickly progressed from feeling fine to experiencing acute respiratory arrest and subsequent death, Manouchkathe Cassagnol, PharmD, BCPS, BCCP, told Pharmacy Today, describing what occurred during the surge in New York this past spring. It was not until the pathology reports were available that clinicians realized, “people are dying of clots,” she said. Cassagnol is a clinical specialist for cardiovascular pharmacotherapy at Nassau University Medical Center and an associate clinical professor in the College of Pharmacy and Health Sciences at St. John’s University in Queens, NY.
“Sometimes there wouldn’t be evidence of clots,” but D-dimer would be increased to “incredible levels,” said Peter Marshall, MD, MPH, who is in the midst of the patient surge on the opposite side of the country in Los Angeles. Marshall is vice chief for medical critical care and clinical associate professor at the University of Southern California’s Keck School of Medicine.
Studies show abnormal clotting
In a report published in February by the Journal of Thrombosis and Haemostasis, Tang and colleagues analyzed coagulation-related data from 183 Chinese patients aged 14 to 94 years. They found that the 21 patients (11.5%) who succumbed to COVID-19–induced pneumonia had higher levels of D-dimer protein and fibrin degradation product (FDP) at admission than survivors. Both D‐dimer and FDP are formed in the bloodstream upon the dissolution of blood clots. Nonsurvivors also had longer prothrombin and activated partial thromboplastin times, which indicates increased clotting times.
In another study, researchers investigated the risk factors for death among adult inpatients with COVID-19. They found an 18-fold increased risk of death among those with a D-dimer greater than 1 mcg/mL. This study, published in Lancet by Zhou and colleagues in March, included 191 COVID-19–positive individuals aged 18 to 87 years who had either been discharged (137) or died (54) during their hospitalization.
Strategies for prevention
Based on such findings, Chinese experts published a consensus statement in the Chinese Journal of Infectious Diseases recommending routine anticoagulation with low molecular weight heparin (LMWH) or unfractionated heparin, depending on D-dimer levels.
The American Society of Hematology followed suit, recommending on their website the prophylactic use of LMWH in patients hospitalized with COVID-19 “unless the risk of bleeding outweighs the risk of thrombosis.” The organization also recommends increased intensity of prophylactic anticoagulation among patients with recurrent clotting of arterial lines or other access devices while on prophylaxis.
Marshall said he has encountered clotting on such devices (i.e. dialysis instruments and catheters) in patients with no history of clotting problems. To combat this, his hospital adopted a strategy to assign patients an anticoagulation level: level 1 for regular prophylaxis, level 2 “to more aggressively prevent clotting in patients showing a propensity towards clotting,” and level 3 for full anticoagulation.
Considering no evidence of increased bleeds, “this was an intervention that came with possible benefits and very few downsides,” he said.
Cassagnol is also concerned about patients experiencing COVID-19 symptoms outside of hospitals, however. “What do we tell people at home about how to prevent coagulopathies,” she asked. Individuals not sick enough for hospitalization during the peak of the New York crisis were sent back home, “and many of them, especially people of color, died … and many died of coagulopathies.”
When she herself experienced the disease, Cassagnol said she “made it a point to move around,” despite feeling too sick to do so. Others experiencing COVID-19 symptoms outside the hospital should do the same, she said: “Move around with appropriate social distancing.”