Pulmonary embolism with clot in transit: An analysis of risk factors and outcomes

Clot in transit (CIT) represents a rare and life-threatening manifestation of venous thromboembolism of which we have limited understanding. This study describes the risk factors, clinical characteristics, and outcomes associated with the development of CIT as well as death following CIT diagnosis.

We analyzed patients enrolled in our institutional Pulmonary Embolism Response Team (PERT) registry and compared 57 patients who had a CIT to 608 pulmonary embolism (PE) patients who did not have a CIT. We performed univariate and multivariate logistic regression to identify factors associated with CIT (vs PE without CIT) among patients who had an echocardiogram, as well as factors associated with 7-day death after CIT diagnosis.

CIT was present in (57) 8.6% of patients who had an echocardiogram. Multivariate analysis showed heart failure (OR 2.8, 95% CI 1.2-6.5, P = 0.01), a pre-existing central venous catheter (OR 2.5, 95% CI 1.1-5.7, P = 0.03), and hypotension (OR 2.1, 95% CI 1.1-3.7, P = 0.02) to be independently associated with CIT. All-cause mortality by 7 days was higher in CIT patients (12.5% vs 5.1%, P = 0.02). CIT patients who died were more likely to have presented with hemodynamic collapse (57.1% vs 14.0%, P = 0.02), mental status change (100% vs 22.0%, P < 0.001), and to be intubated (100% vs 36.0%, P = 0.001).

The presence of heart failure, a central venous catheter, and hypotension should alert physicians to patients who may require an echocardiogram to diagnose CIT. The mortality of CIT is high, even relative to a population with severe PE.