Clinical question: Does therapeutic-dose anticoagulation, compared to prophylactic dosing, improve clinical outcomes in adults with sickle cell disease hospitalized for acute chest syndrome (ACS)?
Background: ACS is a leading cause of morbidity and mortality in sickle cell disease, with pulmonary microthrombosis implicated in its pathogenesis; current practice typically uses prophylactic anticoagulation, but the benefit of therapeutic dosing has not been established.
Study design: Double-blinded, multi-center, prospective, randomized, controlled trial
Setting: 12 hospitals in France
Synopsis: The TASC trial randomized 172 adults with sickle cell disease and ACS (without initial thrombosis on CT pulmonary angiogram) to receive either prophylactic or therapeutic doses of low-molecular-weight heparin tinzaparin for seven days, or until hospital discharge. The primary outcome of time to ACS resolution was significantly lower in the therapeutic group (hazard ratio [HR] 0.71; 95% confidence interval [CI], 0.51 to 0.99; P=0.044), with a mean reduction of 1.3 days. No major bleeding events occurred in either group. The therapeutic group also had lower cumulative parenteral opioid use. Other secondary outcomes, including transfusion rates, mortality at discharge, and six-month readmissions, were similar. Limitations include the trial’s restriction to adults and its single-country setting, which may affect generalizability. The sample size (172 patients) may limit its power to detect rare adverse events, particularly major bleeding, which did not occur in either group. Finally, the trial used a specific low-molecular-weight heparin (tinzaparin), so results may not be directly applicable to other anticoagulants or dosing strategies.
Bottom line: Therapeutic-dose anticoagulation with tinzaparin shortens ACS duration and reduces opioid use in adults with sickle cell disease hospitalized for ACS, without increasing major bleeding risk.
Citation: Dessap AM, et al. Comparison of prophylactic and therapeutic doses of anticoagulation for acute chest syndrome in sickle cell disease: the TASC randomized clinical trial. Am J Respir Crit Care Med. 2025;211(5). doi:10.1164/rccm.202409-1727OC.
Dr. Morris is a hospitalist at Yale New Haven Hospital in New Haven, Conn. She directs the Smilow Hospitalist service, a hospital medicine group dedicated to the care of oncology patients.