Comparison of Ultrasound-Accelerated versus Pigtail Catheter-Directed Thrombolysis for the Treatment of Acute Massive and Submassive Pulmonary Embolism 

Summary

This retrospective study expounds on the use of catheter directed lytic therapy in the setting of submassive and massive pulmonary embolism. Its specific aim is to directly compare the effectiveness of ultrasound-accelerated therapy (USAT) to that of nonselective flush catheter (PCDT) thrombolytic infusions. The authors reviewed 101 treatments over a 7 year period, and after exclusion criteria, included 60 treatments in 59 patients, 24 of whom received USAT and 36 of whom received PCDT. Demographics of the two cohorts were similar. Therapy selection was at the discretion of the performing physician, as was thrombolytic dosing and duration. The results demonstrated similar effectiveness of the two techniques, as demonstrated by improved pulmonary artery pressures and Miller index scores (angiographic thrombus scoring system). Placement of the pigtail catheters compared to the USAT catheters took significantly less procedure and fluoroscopy time. There was a nonsignificant trend towards PCDT taking longer, requiring more procedural revisits, and consequently, resulting in an increase in total lytic therapy. However, when normalizing to the first revisit, these trends were no longer observed. There were a total of three 30-day mortalities, only one of which could be directly attributed to lytic therapy. The authors conclude that the clinical efficacy and safety of these two CDT techniques is similar, with the PCDT taking less time to initiate.



Table 3. Reduction in Parameters between Procedures within Groups

Commentary

There has been significant interest in the use of catheter directed therapy (CDT) in the setting of both massive and submassive pulmonary embolism. An increasing body of literature advocates for the use of CDT in both massive and submassive PE. Both patient populations have seen avoidance of hemodynamic collapse, improved PA pressures, decreased thrombus burden, and improved RV function after use of lytic therapy. However, there is little clinical evidence to guide the best technique for administration of this lytic therapy. This paper attempts to shed insight on this matter by comparing USAT to PCDT in a retrospective fashion at a single center. Prior in vivo research has suggested that flow dynamics in the setting of obstruction require infusions to be imbedded in the obstruction for appropriate medication instillation. However, the clinical applicability of this research is not well known. Certainly, USAT has demonstrated effectiveness to lyse thrombus, and some have shown it also to allow a smaller amount of lytic to be administered over a shorter period of time. However, the current study would argue against this literature when applied to routine clinical practice, especially given the similar outcome endpoints, decreases in procedural complexity, and decreased procedure times.

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Graif A, Grilli CJ, Kimbiris, G et al. Comparison of Ultrasound-Accelerated versus Pigtail Catheter-Directed Thrombolysis for the Treatment of Acute Massive and Submassive Pulmonary Embolism. J Vasc Interv Radiol. 2017; 28(10): 1339-1347.

Post Author:
Daniel P. Sheeran, MD
Assistant Professor
Department of Radiology and Medical Imaging
Division of Vascular and Interventional Radiology
University of Virginia