Is there an optimal "door to cath time" in the treatment of acute pulmonary embolism with catheter-directed thrombolysis?

Ultrasound assisted catheter-directed thrombolysis (UACT) is a relatively novel approach to treating acute pulmonary embolism (PE). It is an alternative to systemic thrombolysis with good success rates and low reported in-hospital mortality, and low rates of procedure-related major and minor bleeding. Since UACT received FDA approval for the treatment of PE in 2014, there is paucity of data regarding the optimal timing of initiation of the procedure after the initial diagnosis is made. We reviewed the available literature regarding UACT for acute PE and found six studies that included time to procedure. Based on our review, patients may benefit from early (<24-48 h after presentation) rather than delayed (>48 h) initiation. Early initiation of therapy has shown to improve pulmonary arterial pressures, right ventricular (RV) to left ventricular (LV) ratios, with low rates of bleeding and low post procedural and in hospital mortality. However, further studies are required to confirm these findings and establish the appropriate timeline for initiation of UACT.