FLAME Massive PE Study – FlowTriever for Intravascular Thrombectomy
December 8, 2023
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Written by Chris Thom
Spoon Feed
In this non-randomized prospective study, patients with massive pulmonary embolism who were treated with the intravascular FlowTriever thrombectomy device had improved outcomes compared to those treated with other therapies.
Should we remove the clot via intravascular thrombectomy?
This prospective, observational study enrolled patients at 11 institutions presenting with severe pulmonary embolism, as defined by hypotension < 90 mmHg, need for vasopressor support, or cardiac arrest < 30 minutes. Patients received the FlowTriever mechanical thrombectomy device (53 patients) or other therapies (61 patients). Discretion for the choice of therapy was left up to the treatment team. Patients in the non-FlowTriever group received other therapies including systemic thrombolysis (42/61), anti-coagulation alone (14/61), catheter-directed lysis (4/61), and surgical embolectomy (1/61).
The primary end point was a composite score of all-cause mortality, need for alternate thrombus removal strategy, clinical deterioration, and major bleeding. A performance goal of 32% was used based on data available for similar patients in prior studies. 9/53 (17%, 95 CI 8.1%-29.8%) patients in the FlowTriever arm had the primary endpoint, which was significantly lower than the aforementioned 32% goal (p<0.01). In the non-FlowTriever arm, 39/61 patients (63.9%, 95 CI 0.5%-13.0%) experienced the primary endpoint. Mortality was 1.9% in the FlowTriever group and 29.5% in the non-FlowTriever group.
Importantly, there were several key differences in the two patient cohorts. The Society for Cardiovascular Angiography and Intervention shock stage indicated a higher severity of illness in the non-FlowTriever group, and the rate of cardiac arrest was also higher (32.8% in non-FlowTriever and 20.8% in FlowTriever).
How will this change my practice?
While the results of this study show promise, there is reason to hesitate in considering widespread adoption of this particular thrombectomy device based on this single study. The groups had important differences in severity of illness, and the study was non-randomized and likely suffers from selection bias. The study was also industry funded. Evidence directly comparing intravascular thrombectomy, catheter directed thrombolysis, surgical embolectomy, and systemic thrombolysis remains limited.
Another spoonful: AHA Statement – Surgical Embolectomy and ECMO for High-Risk PE
Post amended 12/8/24 11:45AM CST – We used the word “trial” in the original version of this summary. This should have read “study,” as this was not a trial. It was a prospective observational study. ~Clay Smith
Source
Outcomes in High-Risk Pulmonary Embolism Patients Undergoing FlowTriever Mechanical Thrombectomy or Other Contemporary Therapies: Results From the FLAME Study. Circ Cardiovasc Interv. 2023;16(10):e013406.