Prophylactic versus Therapeutic Anticoagulation for Acute Chest Syndrome in Sickle Cell Disease
TASC trial design and results
Design
Double-blind randomised controlled trial
Treatment
Therapeutic-dose anticoagulation
Control
Prophylactic-dose anticoagulation
Population
172 adults with sickle cell disease hospitalised for acute chest syndrome across 12 French hospitals, with no initial thrombosis on CT pulmonary angiogram
Follow-up
15 days or discharge
Primary endpoint
Time to resolution of acute chest syndrome
Result
Time to resolution of acute chest syndrome was shorter with therapeutic anticoagulation (hazard ratio 0.71, 95% CI 0.51 to 0.99, p=0.044). Restricted mean time to resolution over a 15-day horizon or to discharge was 4.8±0.4 versus 6.1±0.5 days. Major bleeding, the primary safety outcome, occurred in neither group. Cumulative parenteral opioid use was lower with therapeutic dosing — median 124 mg (IQR 80 to 272) versus 219 mg (IQR 65 to 378) morphine equivalent, difference -96 mg (95% CI -202 to -46, p=0.02).
Secondary endpoints
Opioid consumption, oxygen requirement, length of stay, major bleeding
In adult patients with ACS, a therapeutic anticoagulation shortened ACS duration and reduced opioid consumption compared with prophylactic doses, without increasing bleeding risk.
The trial authors, in the published abstract
How it has aged
Acute chest syndrome sits between thrombosis and infection, and this is the first randomised support for treating the thrombotic component directly. The opioid reduction is the finding patients would actually notice. With 172 patients and no major bleeding in either arm, the trial cannot exclude a bleeding risk that a larger study would detect, and the primary hazard ratio reaches significance only marginally.
Publications
Comparison of Prophylactic and Therapeutic Doses of Anticoagulation for Acute Chest Syndrome in Sickle Cell Disease: The TASC Double-Blind Controlled Randomized Clinical Trial
Mekontso Dessap A, Habibi A, Arlet JB, et al. Comparison of Prophylactic and Therapeutic Doses of Anticoagulation for Acute Chest Syndrome in Sickle Cell Disease: The TASC Double-Blind Controlled Randomized Clinical Trial. Am J Respir Crit Care Med 2025 May;211(5):832-841.