Acute chest syndrome (ACS), characterized by dyspnea, chest pain, and opacities on chest radiograph, is a poorly understood complication of sickle cell disease, and its pathology is thought to result from microvascular occlusion as well as fat embolization. French researchers assessed the incidence of macrovascular pulmonary artery thrombosis ”“”“ previously ill-defined ”“”“ in this setting. One hundred three patients who suffered 121 ACS episodes underwent multidetector computed tomography (MDCT). Seventeen percent of studies were positive for thrombosis, and most (75%) involved segmental clots. Interestingly, all patients with positive MDCT scans also underwent Doppler ultrasound of the lower extremities, and none of these tests were positive. Magnetic resonance imaging was negative for fat in the clots. Traditional screening tests for venous thromboembolism, including D-dimer concentrations and Geneva score, were not predictive of thrombosis. Patients with positive scans did have higher platelet counts as well as lower levels of hemolysis markers (i.e., lactate dehydrogenase, total bilirubin) than other patients. Comment: Whether pulmonary artery thrombosis is a cause or a complication of ACS remains unclear, but these patients have a substantial incidence of macrovascular clots, which appear to be more likely in situ than embolic. We don't have enough data to warrant routine CT in patients with ACS, because we don't know whether anticoagulation or antiplatelet agents would improve outcomes, and they could potentially lead to more complications. However, clinicians might consider selective CT in patients with ACS who are not responding to conventional management. source : How Prevalent Is Pulmonary Thrombosis During Acute Chest Syndrome? - Journal Watch (General)
