The FlowTriever System shows positive longer-term safety profiles and low mortality rates in a large, geographically diverse cohort of patients with acute intermediate- and high-risk pulmonary embolism (PE), according to new 6-month study results.

Sameer Khandhar, MD, of the Penn Presbyterian Medical Center, Philadelphia, presented these results during a late-breaking trial session Friday at the Society for Cardiovascular Angiography & Interventions (SCAI) 2023 Scientific Sessions in Phoenix.

Decreased quality of life (QoL) and reduced exercise capacity are long-term effects in patients who experience PE, which is already associated with short- and long-term morbidity and mortality. The typical short-term treatment for PE is mechanical thrombectomy, but the long-term outcomes of this management plan are unknown.

This prospective, single-arm study—FLASH (FlowTriever All-Comer Registry for Patient Safety and Hemodynamics)—evaluated patients (initial n=800, 75.0% completed the study) treated with the FlowTriever mechanical thrombectomy from follow-up to 6-months post-treatment. All-cause mortality was observed at 48-hour visit (0.3%), 30-day visit (0.8%) and 6-month study exit (4.6%). The FlowTriever system was unrelated to all-cause mortality, pulmonary injuries or cardiac injures.

There was a significant decrease in mean right ventricular (RV)/left ventricular ratio from baseline (1.23) to 48 hours (0.98), to 30 days (0.78), to 6 months ( 0.80, p<0.001 compared to baseline for all three follow-up timepoints). There was also significant improvement observed in RV function from baseline (15% with normal RV function) to 48 hours (39.5%), to 30 days (89.6%), to 6 months (95.1%; p<0.001 compared to baseline for all three timepoints).

Patient-reported functional outcomes—no or mild dyspnea (baseline: 21.9%, 48 hours: 67.4%, 30 days: 83.1%, 6 months: 90.1%, p<0.001 compared to baseline for all three timepoints), walking distance (median 6-minute walk test: 48 hours, 180 m; 30 days, 375.6 m; 6 months, 398.1 m; p<0.001 trend over time) and quality-of-life score (30 days: 9.38, 6 months: 4.85 [lower score is better]; p<0.001 both timepoints)—all demonstrated early, significant improvements, as well as progress out to 6 months.

Overall, RV recovery, as well as favorable long-term safety and low mortality was observed in patients who received treatment via the FlowTriever System. The investigators noted that large-bore mechanical thrombectomy can give short- and long-term benefits for intermediate- and high-risk patients with PE.

Khandhar concluded that the majority of right heart recovery was achieved within the first 30 days. He added that the study suggests that “large-bore mechanical thrombectomy can offer not only acute but longer-term benefits for intermediate- and high-risk PE patients.”

More follow-up studies on this topic are necessary, too, Khandhar emphasized during a press conference  Friday.

“We owe it to the patients to not only focus on their survival of the PE, but also [long term symptom improvement] and quality of life,” he said.

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