Mechanical Thrombectomy Device Effectively Treats Intermediate-Risk PE Without Thrombolysis

Pulmonary Embolism
Pulmonary Embolism
Mechanical thrombectomy with the FlowTriever system appears to effectively treat intermediate-risk pulmonary embolism.

In patients with acute intermediate-risk pulmonary embolism (PE), the single-use percutaneous FlowTriever mechanical thrombectomy device system (Inari Medical, Irvine, California) is a safe and effective strategy for improving right ventricular (RV)/left ventricular (LV) ratios, according to a study published in JACC Cardiovascular Interventions. Advantages for using this system include immediate thrombus removal and decreased post-procedural critical care requirement.

The researchers enrolled 106 patients with symptomatic, computed tomography-documented proximal PE and RV/left ventricular (LV) ratios of ≥0.9 in the prospective single-arm FLARE trial ( Identifier: NCT02692586). Patients were treated with the FlowTriever System and underwent pulmonary angiographic and hemodynamic assessment.

The primary efficacy end point included the core laboratory-assessed change in RV/LV ratio. In addition, the researchers evaluated 48-hour device-related death, major bleeding, treatment-related clinical deterioration, pulmonary vascular injury, or cardiac injury in the primary safety end point.

In the overall cohort, the mean procedure time was 94 minutes and mean intensive care unit stay was 1.5 days. Approximately 41% of patients (n=43) did not require a stay in the intensive care unit.

There was a significant reduction in the average RV/LV ratio of 3.8 at 48 hours after thrombectomy (25.1%; P <.0001). Only 3.8% of patients (n=4) experienced 6 major adverse events and only 1% had major bleeding.

Mortality occurred in 1 patient; however, this was due to undiagnosed breast cancer via a 30-day follow-up.

Study limitations include the small sample size and the lack of a randomized control group.

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Due to the study’s limitations and short follow-up, the researchers concluded that additional research is needed to compare this specific therapy with other catheter-directed treatments.

“Mechanical thrombectomy using the FlowTriever system, without thrombolysis, appears safe and effective to treat intermediate-risk PE and should now be considered as a potential therapy for this condition,” the study investigators concluded.


Clinical trial NCT02692586 was sponsored by Inari Medical. Multiple study authors disclosed relationships with pharmaceutical industry.


Tu T, Toma C, Tapson VF, et al; for the FLARE Investigators. A prospective, single-arm, multicenter trial of catheter-directed mechanical thrombectomy for intermediate-risk acute pulmonary embolism: The FLARE study. JACC Cardiovasc Interv. 2019;12(9):859-869.