Traumatic primary pulmonary thrombosis: injury and treatment patterns of a distinct clinical entity

Traditionally, pulmonary thrombi following trauma were believed to occur secondary to embolization from deep vein thrombosis (DVT). However, computed tomography (CT) during initial trauma resuscitation has identified pulmonary thrombi, which raises the possibility of primary pulmonary thrombosis as a distinct clinical entity. This study identifies cases of pulmonary thrombosis identified immediately after trauma and describes associated injury patterns and treatments.

We conducted a retrospective review of the trauma and radiology registries at a Canadian level-1 trauma centre from January 2010 to April 2021. A chart review identified patients with pulmonary thrombi on initial CT. We extracted and analyzed patient demographic characteristics, mechanism of injury, summary of injuries, treatments, and outcomes.

A total of 24 patients (15 male, 9 female; mean age 54, standard deviation [SD] 18.6, yr) met the inclusion criteria. All patients experienced blunt trauma (mean Injury Severity Score 23.5, SD 9.5). Rib fractures (n = 11, 46%), pneumohemothorax (n = 7, 29%), and spinal fractures (n = 8, 33%) were common. Four patients had a concomitant DVT, and 10 patients did not undergo assessment for DVT; 10 patients were identified as having primary pulmonary thrombosis. Treatment was started in 18 patients (75%): 9 patients were treated with dalteparin, 2 with dalteparin and inferior vena cava (IVC) filter, 6 with IVC filter in isolation, and 1 with IVC filter and intravenous heparin. Five patients (21%) died from their injuries.

Early pulmonary thrombosis was associated with chest injuries, often without DVT. These findings challenge the traditionally held view of DVT embolization as the cause of pulmonary thrombosis immediately following trauma and suggest that primary pulmonary thrombosis is a distinct clinical entity.