Effect of Pharmacomechanical Catheter-Directed Thrombolysis on Segmental Artery Occlusions: Insights From the RESCUE Trial

Background: Reduction in distal vascular volume in acute pulmonary embolism (PE) is a significant predictor of 30- and 90-day mortality. The likely cause of this is pulmonary arterial obstruction. The effect of pharmacomechanical catheter-directed thrombolysis (PM-CDT) on the occlusions of these pulmonary artery (PA) branches is not known. Objectives: The RESCUE study evaluated PM-CDT with the Bashir endovascular catheter in patients with acute intermediate-risk PE. This analysis assessed PA occlusions using core laboratory data before and after PM-CDT therapy. Methods: The baseline and 48-hour post-treatment contrast-enhanced chest computed tomography angiography of PE patients with right ventricular dilatation enrolled in the RESCUE trial were used. The primary analysis was the change in the number of segmental and proximal PA branches with total or subtotal (>65%) occlusions after 48 hours compared to baseline using McNemar's test. Results: A total of 107 patients enrolled across 18 United States sites comprised this analysis. At 48 hours post-PM-CDT, the number of segmental PA branches with total or subtotal occlusions decreased from 40.5% to 11.7% (P < 0.0001). Proximal PA branch total or subtotal occlusions decreased from 28.7% to 11.0% (P < 0.0001). The reduction in segmental artery occlusions correlated significantly with the magnitude of reduction in right ventricular/left ventricular ratio (correlation coefficient of 0.287 [95% CI: 0.102-0.452]; P = 0.0026), whereas that in the proximal PA arteries did not (correlation coefficient of 0.132 [95% CI: 0.059-0.314] P = 0.173). Conclusions: PM-CDT with the Bashir catheter was associated with a significant reduction in total and subtotal occlusion of segmental and proximal PAs.