Catheter Directed Mechanical Thrombectomy for Intermediate-Risk Acute Pulmonary Embolism: Clinical Outcomes From a Single Center Experience

BackgroundFew single center studies with small sample size have been published showing clinical benefits of endovascular intervention specifically using mechanical suction thrombectomy for P.E. without systemic/catheter lytic therapy. This study will analyze our initial experience and clinical outcomes in the treatment of P.E. using Inari FlowTriever thrombectomy device.Patient Population/MethodsA single center retrospective study of 50 consecutive patients with acute P.E. were treated with the INARI FlowTriever device between January 2019 to June 2023. All patients were submassive P.E. with right ventricular strain (RV/LV ratio >0.9) and requiring oxygen therapy or having increase in oxygen therapy from baseline. Procedural and clinical success (Improvement in intraoperative pulmonary artery pressures and oxygen therapy) were evaluated along with in hospital procedural related complications with a mean follow up of 8 months (range 1-22.5 months).ResultsAll patients were stratified as intermediate high-risk PE with a mean age of 68 years. Right ventricular dilation was present in 100% of patients with a mean RV/LV ratio of 1.55 (range 0.9-2.7). Mean pre-op Troponin was 434 (median 318, range 6-2332) and mean BNP was 352 (median 154, range 60-1787). Procedural success as defined by SIR guidelines was achieved in 100% of patients. There was 0% hospital mortality, device related mortality, or complications including bleeding, and acute kidney injury (AKI). Significant improvement in FiO2 was noted when comparing the mean pre-procedural FiO2 of 40.6% (range of 21%-100%) to a mean of FiO2 of 28.3% (range of 21%-52%) at 24 h post procedure (<i>P</i> < .0001). Proportion of patients on room air increased from 0% pre procedure to 94% at 48 h. The mean pre-op pulmonary artery pressure improved from 47 mm Hg (range 20-74) to mean post pulmonary artery pressure of 34 mm Hg (range 19-65) <i>P</i> < .0001. 97% of patients had a decrease in their pre-op pulmonary pressures intraoperatively.In late follow-up when evaluating pre to post intervention 36/38 (94.4%) of our patients were back to baseline with regards to oxygen requirement. Proportion of patients on room air increased from 0% pre procedure to 94.4% post procedure. 34/38 (89%) of patients reported they were back to baseline in regard to physical activity and 37/38 (97%) of patients reported their breathing status was back to baseline from prior to procedure. Using the modified Medical Research Council Dyspnea Score, 93% of patients reported a pre-op score of four (highest) while 70% reported scores of zero (normal) and or score of one post intervention with 100% showing improvement at 8 month follow up.ConclusionOur study demonstrates both safety and effectiveness in using the INARI FlowTriever for patients with submassive acute pulmonary embolism.