Tag: anticoagulant

Bleeding from Full-dose Anticoagulants in COVID ICU Patients

Photo by Mufid Majnun on Unsplash

COVID patients in intensive care units (ICU) receiving full-dose anticoagulants are significantly more likely to experience heavy bleeding than patients prescribed a smaller yet equally effective dose, according to a recent study.

The research, which compared the safety and effectiveness of blood clot treatment strategies for more than 150 critically ill COVID patients at two hospitals, found that almost all patients who experienced significant bleeding were on mechanically ventilation and receiving full-dose anticoagulants.

The results, published last month in Hospital Pharmacy, may inform treatment guidelines for blood clots in hospitalised COVID patients, who are at an increased risk for both blood clots and severe bleeding. Previous reports have found that 17% of hospitalised COVID patients experience blood clots, said first author Maya Chilbert, PharmD, clinical assistant professor in the UB School of Pharmacy and Pharmaceutical Sciences.

“A wide variety of practice exists when it comes to approaching blood clots in hospitalized patients with COVID, and there is little data to suggest improved outcomes using one strategy versus another,” said Chilbert. “Caution should be used in mechanically ventilated patients with COVID when selecting a regimen to treat blood clots, and the decision to use full-dose blood thinners should be based on a compelling indication rather than lab markers alone.”

The study analysed the outcome of blood clot treatments and the rate of bleeding events for more than 150 patients with COVID-19 who received either of two blood thinner regimens: a full-dose based on patient levels of D-dimer, and the other a smaller but higher-than-standard dosage.

Patients’ average age was 58, and all experienced elevated levels of D-dimer, fibrinogen, and prothrombin time.

Significant bleeding events were experienced by almost 14% of patients receiving full-dose anticoagulants, compared to only 3% of patients who received a higher-than-standard dosage. All patients who experienced bleeding events were on mechanical ventilation. No difference was reported in the regimens’ effectiveness at treating blood clots.
Further investigation is needed to determine the optimal strategy for treating blood clots and bleeding in hospitalised COVID patients, said Asst Prof Chilbert.

Source: University at Buffalo

Tick Saliva Yields Powerful Anticoagulants

Source: Wikimedia CC0

A novel study has isolated powerful anticoagulants from the saliva of ticks, which may have reduced potential for bleeding.

Blood-feeding animals rely on specific molecules in their saliva to overcome defence mechanisms of their mammalian hosts for successful survival. The saliva of ticks, for example, contains molecules that can prevent blood from clotting, and which can also suppress inflammation or immune response to enable continuous feeding on the same bite site for days, sometimes undetected by the host. The harmful effects of these parasites can actually be harnessed for medical treatments.

In their paper, published in Nature Communications, the authors explain how the cardiovascular team developed a series of thrombin inhibitors to be potent anticoagulants based on sequences of inhibitors of blood coagulation enzyme thrombin found in the tropical bont tick Amblyomma variegatum.

The team developed a series of thrombin inhibitors to be powerful anticoagulants.

Anticoagulants are used in conditions where there is an increased propensity to form blood clots in our body depriving blood supplies to important tissues and organs, otherwise known as thrombosis. These drugs are needed in many diseases caused by blood clots including heart attacks, strokes, deep vein thrombosis, pulmonary embolism and even some severe complications caused by SARS-CoV-2 infection.

These next-generation anticoagulants will now need to be tested in human trials to determine if they can effectively counteract clotting without the bleeding side effects of currently available anticoagulants.

Source: EurekAlert!

Anticoagulation Improves Survival Odds of Moderately Ill COVID Patients

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If treated with therapeutic-dose anticoagulation, moderately ill patients hospitalised with COVID have better odds of survival, according to an international study published in The New England Journal of Medicine.

COVID patients frequently develop a pro-coagulative state caused by virus-induced endothelial dysfunction, cytokine storm and complement cascade hyperactivation. Thrombotic risk appears directly related to disease severity and worsens patients’ prognosis.

Moderately ill COVID patients treated with therapeutic-dose anticoagulation with unfractionated or low molecular-weight heparin were 27% less likely to need cardiovascular respiratory organ support such as intubation, said Ambarish Pandey, MD, Assistant Professor of Internal Medicine at UT Southwestern, who served as site investigator and . Moderately ill patients had a 4% increased chance of survival until discharge without requiring organ support with anticoagulants, according to the study involving 2200 patients.

“The 4% increase in survival to discharge without needing organ support represents a very meaningful clinical improvement in these patients,” said Dr Pandey, a Texas Health Resources Clinical Scholar specialising in preventive cardiology and heart failure with preserved ejection fraction. “If we treat 1,000 patients who are hospitalized with COVID with moderate illness, an additional 40 patients would have meaningful improvement in clinical status.”

Moderately ill patients were defined as those who did not need intensive care unit-level support. The participating platforms for the study, included Antithrombotic Therapy to Ameliorate Complications of COVID-19 (ATTACC); A Multicenter, Adaptive, Randomized Controlled Platform Trial of the Safety and Efficacy of Antithrombotic Strategies in Hospitalized Adults with COVID-19 (ACTIV-4a); and Randomized, Embedded, Multifactorial Adaptive Platform Trial for Community-Acquired Pneumonia (REMAP-CAP). 

A parallel study reported in The New England Journal of Medicine found however that therapeutic-dose anticoagulation did not help severely ill patients.

Source: UT Southwestern Medical Center