Question special

The supplementary material indicates that a strict criterion was used to mandate the use of CTPA for assessment of PE, including significant hypotension, chest pain or hypoxia. While this would likely capture most of the potentially fatal PE, it may be not be sensitive enough to identify those patients with 'asymptomatic PE', ie those with significant pulmonary vascular clot burden but not large enough to profoundly affect haemodynamics. Asymptomatic PEs and clot burden may be a relevant endpoint in the studied population as it could affect morbidity in terms of the need for therapeutic anticoagulation, length of hospital stay, duration of rehab, etc.

It would be interesting to know if the authors believe or have data to suggest that vena cava filters reduce the pulmonary clot burden and if so, would this warrant further investigation.