PURPOSE:

Few studies have examined conventional catheter directed thrombolysis (CDT) for the treatment of submassive pulmonary embolism (PE). Moreover, angiographic resolution of thrombus burden following CDT has infrequently been characterized. This study describes a single-center experience treating submassive PE with CDT while utilizing repeat angiography to determine treatment efficacy.

METHODS:

A retrospective analysis of 140 consecutive patients who underwent CDT for submassive PE from December 2012 to June 2019 was performed. Angiographic resolution of thrombus burden after CDT was reported as high (>75%), moderate (51-75%), low (26-50%), or insignificant (≤25%). All angiograms were reviewed by two interventional radiologists. Secondary endpoints included reduction in pulmonary artery pressure (PAP) and clinical outcomes. Bleeding events were classified according to the Society of Interventional Radiology (SIR) adverse event criteria.

RESULTS:

CDT was performed in 140 patients with a mean rtPA dose of 25.3 mg and a mean treatment time of 26.0 hours. Angiographic resolution of thrombus burden was high in 70.0%, moderate in 19.3%, low in 5.7%, and insignificant in 3.6%; in 2 patients (1.4%) repeat angiography was not performed. Systolic PAP was reduced (47 vs. 35 mmHg, p < 0.001), mean PAP was reduced (25 vs 21 mmHg, p < 0.001), and 129 patients (92.1%) improved clinically. Patients with high or moderate resolution of thrombus burden had a clinical improvement rate of 95.2%, while patients with low or insignificant thrombus burden resolution had a clinical improvement rate of 76.9% (p=0.011). Ten patients (7.1%) had hemodynamic or respiratory decompensation requiring mechanical ventilation, systemic thrombolysis, cardiopulmonary resuscitation, or surgical intervention. Seven patients (5.0%) experienced moderate bleeding events and one patient (0.7%) with metastatic disease developed severe gastrointestinal bleeding that resulted in death. Thirty-day mortality was 1.4%.

CONCLUSION:

In patients with submassive PE undergoing CDT, angiographic resolution of thrombus burden is a safe and directly observable metric that can be used to determine procedural success. In this study, CDT with repeat angiography was associated with a 5.7% bleeding event rate and thirty-day mortality of 1.4%.