VIDEO: Evidence mounts for pulmonary embolism benefit from catheter thrombolysis

TORONTO – Catheter-directed thrombolysis of pulmonary embolism using an ultrasound-assisted device led to significantly better outcomes in patients hospitalized for pulmonary embolism, compared with conventional systemic thrombolytic treatment, in a propensity score–adjusted analysis of nearly 3,400 patients.

Catheter-directed thrombolysis (CDT) “represents an opportunity to locally treat pulmonary embolism with significant thrombus burden with lower bleeding complications,” Abhishek Mishra, MD, said at the CHEST annual meeting. “I think we are underusing CDT,” said Dr. Mishra, a cardiovascular disease physician at Guthrie Robert Packer Hospital in Sayre, Pa.

Although one CDT device, the EKOS endovascular system that uses ultrasound to facilitate pulmonary embolism (PE) thrombolysis, received Food & Drug Administration approval for U.S. marketing in 2014, the trials that have compared it with systemic thrombolysis have been small, noted Dr. Mishra, and none have looked at whether CDT improves patient survival, compared with standard treatments. The largest report on CDT treatment of PE came from a single-arm, uncontrolled study with 150 patients who received ultrasound-facilitated CDT (JACC Cardiovasc Interv. 2015 Aug;8[10]:1382-92).

To better document the incremental benefit from CDT, Dr. Mishra and his associates used data collected by the Nationwide Readmissions Database during 2013 and 2014, both before and after a CDT device became available for U.S. use. From among 4,426 patients hospitalized with a primary diagnosis of PE and treated with thrombolytic therapy, they used propensity score matching to compare 2,256 patients treated with systemic thrombolysis with 1,128 matched patients treated with CDT using tissue plasminogen activator.

The analysis showed that in-hospital death was 15% in the systemic patients and 6% in the CDT group, a relative risk reduction of 63%, and 30-day readmissions occurred in 11% of the systemic patients and in 8% of those treated with CDT, a 30% relative risk reduction. Both were statistically significant differences for the study’s two primary endpoints, Dr. Mishra reported at the meeting. Rates of intracerebral hemorrhage and gastrointestinal bleeds were both numerically lower with CDT, and significantly lower for gastrointestinal bleeds.

The researchers also ran a multivariate analysis on their data that showed CDT was linked with significant relative reductions of about 60% for both in-hospital death and 30-day readmissions, compared with patients on systemic therapy. The results Dr. Mishra reported also appeared in a published report (Am J Cardiol. 2017 Nov 1;120[9]:1653-61).

These findings help buttress the case for using CDT for at least some PE patients. “The key is which patients need it. What is the best way to stratify patients?” commented Victor F. Tapson, MD, a pulmonologist at Cedars-Sinai Medical Center in Los Angeles.

“Patients with PE and a normal right ventricle generally don’t need anything more aggressive than anticoagulation, and really sick patients with massive PE need systemic thrombolytics. Intermediate-risk patients” are best suited to CDT, but “the problem is that intermediate-risk patients are heterogeneous,” Dr. Tapson said in a video interview. Future studies should establish a more specific subgroup of intermediate-risk patients who benefit from routinely employed CDT, he suggested.

mzoler@frontlinemedcom.com

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