Initial Experiences with Endovascular Management of Submassive Pulmonary Embolism: Is It Safe?

Background: Interventional strategies for massive and submassive pulmonary embolism (smPE) have historically included either systematic intravenous thrombolytic alteplase or surgical embolectomy, both of which are associated with significant morbidity and mortality. However, with the advent of endovascular techniques, recent studies have suggested that an endovascular approach to the treatment of acute smPE may be both safe and effective with excellent outcomes. The purpose of this study was to evaluate the outcomes of patients who have undergone catheter-directed thrombolysis (CDT) for smPE at our institution in an effort to determine the safety of the procedure.

Methods: A retrospective review was conducted from December 2012 to June 2015 to identify patients whom underwent CDT in the treatment of a smPE at our institution. Primary measure was safety of the procedure. Outcome variables were classified as serious or minor adverse events. Serious events included death, stroke, myocardial infarction, and bleeding complications requiring surgical intervention or transfusion. Minor events included groin hematoma, development of arteriovenous fistula, and bleeding requiring interruption or cessation of CDT. In addition, a secondary measure included effectiveness of CDT based on preinterventional and postinterventional clinical examination and radiographic findings.

Results: A total of 27 patients undergoing CDT for smPE at our institution were evaluated. The standard procedure included access via bilateral femoral veins and placement of bilateral EKOS catheters for ultrasound-assisted thrombolysis (USAT), with Activase (alteplase) at 1 mg per hour in each catheter for a total of 12 hr. There were no serious adverse events and only 4 patients (14.8%) had minor events, of which only 1 patient required premature termination of therapy due to bleeding resulting in a 3.7% clinically relevant bleeding rate. In addition, a reduction in a right-to-left ventricular end-diastolic diameter ratio (RV/LV ratio) on follow-up imaging was observed in each of the 18 patients where preinterventional and postinterventional imaging was available. Likewise, via chart review, all patients reported significant cessation of shortness-of-breath and resolution of chest pain with associated decrease in supplemental oxygen requirement.

Conclusions: Current evidence, the majority of which has been industry funded, suggests that CDT should be considered as the first-line therapy for smPE. Our experience, in this single-institution retrospective review, demonstrates that CDT with USAT in the treatment of smPE is safe, while providing immediate resolution of both RV strain and clinical symptoms such as shortness-of-breath and chest pain. We hope that these data will allow other institutions to consider CDT as a plausible option in the treatment of smPE.