Outcomes With Catheter-Directed vs Systemic Thrombolysis in Intermediate-Risk Pulmonary Emboli

Right-sided heart pressures, mortality rate, subsequent chronic thromboembolic pulmonary hypertension (CTPH), bleeding risk, and procedural complication rates may not differ in patients with an intermediate-risk pulmonary embolism (PE) treated with catheter-directed thrombolysis (CDT), systemic thrombolysis (ST), or therapeutic anticoagulation (AC), according to a study published in the Annals of the American Thoracic Society.

A systematic review of published data examining the treatment of patients with intermediate-risk PE utilizing CDT was performed to determine the efficacy and safety of CDT compared with ST and AC. 

Only one of the studies reviewed (ULTrasound Accelerated ThrombolysIs of PulMonAry Embolism [ULTIMA]; ClinicalTrials.gov Identifier: NCT01166997) was a prospective randomized control trial. 

Patients enrolled in ULTIMA were randomly assigned to receive either heparin and CDT or heparin alone. Results demonstrate right ventricle/left ventricle (RV/LV) ratio improvement with CDT compared with AC. However, there were no differences found between the 2 treatment modalities in 90-day mortality, hemodynamic compensation, or mean hospital stay. 

Overall, no differences were found in the RV/LV ratio in patients who underwent CDT compared with AC alone. The mortality rate was also low, with no differences seen between treatment groups in studies of patients with intermediate-risk PE alone.  Mortality rates were higher in both high- and intermediate-risk PE patient populations combined, but it is suspected the rate would be lower if only intermediate-risk PE patient mortality rates were analyzed.

Major bleeding rates in patients treated with ultrasound antithrombolysis therapy (USAT) were 2.3% and 3.6%, while CDT rates in all CDT trials were 2.8% to 11.1%, with the highest rates reported in a small trial study. Of note, the minor bleeding rates were approximately 10% to 13% for both interventions, with a slightly higher frequency in patients treated with CDT.

No statistical difference in mortality was found in a meta-analysis of patients with high and intermediate-risk PE treated with USAT compared to CDT.

Investigators concluded from the review of literature that current evidence does not show a significant difference in right-sided heart pressures, mortality rates, or subsequent CTEPH in patients treated with either CDT or AC alone. 

Further, no benefit was noted using USAT compared with CDT. A lower rate of procedural complications was associated with CDT, but possibly a higher major bleeding risk when compared with AC alone. Further research is needed before CDT can be adopted as routine treatment in patients who present with an intermediate-risk PE.

Reference

Furfaro D, Stephens RS, Streiff MB, Brower R. Catheter directed thrombolysis for intermediate-risk pulmonary embolism [published online October 26, 2017]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201706-467FR