FLASH All-Comers Registry Evaluates Inari’s FlowTriever Mechanical Thrombectomy Device for PE

May 19, 2023—The Society for Cardiovascular Angiography & Interventions (SCAI) announced that 6-month outcomes from FLASH showed that patients with pulmonary embolism (PE) who were treated with mechanical thrombectomy showed significant improvement in symptoms, quality of life, and cardiac functions. FLASH is a prospective, single-arm, multicenter registry of acute PE patients treated with the FlowTriever system (Inari Medical, Inc.).

The FLASH data were presented as late-breaking clinical research at the SCAI 2023 Scientific Sessions held May 18-20 in Phoenix, Arizona.

According to SCAI, the assessed 6-month clinical outcomes included Modified Medical Research Council (mMRC) dyspnea score, right ventricular (RV) function, 6-minute walk test (6MWT) distances, and PEmb-QoL scores.

The trial enrolled 800 patients across 50 sites in the United States; 54.1% of patients were male, and the mean age was 61.2 years. Thrombolytic contraindications were reported in 32.1% of patients; 77.1% of patients were classified as intermediate-high risk and 8% as high risk. Most patients (74.8%) completed all study visits through 6-month follow-up.

In 599 patients who completed 6-month follow-up, multiple statistically significant functional and clinical improvements were reported during the study period.

As summarized in the SCAI press release, the FLASH outcomes included the following:

• The proportion of patients with normal echocardiographic RV function increased from 15.1% prethrombectomy to 95.1%; 94% had normal pulmonary artery pressures.
• All-cause mortality was 0.3% at the 48-hour visit, 0.8% at the 30-day visit, and 4.6% at study exit (median = 199 days posttreatment).
• Patient exercise tolerance and symptoms improved significantly after treatment. 6MWT distances increased from 180 meters at 48 hours posttreatment to 398 meters.
• The median mMRC dyspnea score improved from 3.0 at baseline to 0.0 (P < .0001).
• The percentage of patients with normal RV function on echocardiography increased from 15.1% at baseline to 95.1% (P < .0001), and RV systolic pressure ≤ 40 mm Hg improved from 28.4% at baseline to 93.9%.
• The 6-month prevalence of site-reported chronic thromboembolic pulmonary hypertension was 1.0% and chronic thromboembolic disease was 1.9%.

“It’s encouraging to see the dramatic and rapid improvement in both clinical outcomes and daily activities of our patients, like taking a walk without running out of breath,” commented study investigator Sameer Khandhar, MD. “We’re hopeful these FLASH data serve as a next step in understanding the importance of thrombectomy as a treatment option for patients that shows in their recovery and improvements in day-to-day quality of life.” Dr. Khandhar is Assistant Professor of Clinical Medicine at the Perelman School of Medicine at the University of Pennsylvania Penn Presbyterian Medical Center in Philadelphia, Pennsylvania.

In addition to significant improvement in patient symptoms, cardiac function, and quality of life, long-term low mortality was reported after treatment with the FlowTriever system. These data suggest that rapid extraction of thrombus may prevent long-term impact in PE patients, although comparative data relative to conservative management are needed, advised the SCAI press release.