Continuous Aspiration Mechanical Thrombectomy for the management of intermediate- and high-risk pulmonary embolism: Data from the first cohort in Portugal

Introduction This study describes the experience of a reference center using continuous aspiration mechanical thrombectomy for acute high- and intermediate-high-risk pulmonary embolism (PE). Methods Twenty-nine consecutive patients with acute central PE (48.3% high-risk PE; 82.8% in class >III from the original Pulmonary Embolism Severity Index score; median Charlson Comorbidity Index of 4) were treated with the Indigo® Mechanical Thrombectomy System between March 2018 and March 2020. Technical success was defined as successful placement of the device and initiation of aspiration thrombectomy. Clinical success was defined as any improvement in hemodynamic and/or oxygenation parameters, pulmonary hypertension or right heart strain at 48 hours, and survival to hospital discharge. Safety was defined as freedom from severe adverse events potentially related to the procedure. Three-month follow-up results were collected. Results Technical success was 96.6%. Miller index and systolic pulmonary arterial pressure were significantly reduced after the procedure (-5.5±3.0, and -10.2±11.5 mmHg, respectively, both p<0.001). There was a significant improvement in mean paO2/FiO2 ratio (+77.1±103.2; p=0.001), shock index (-0.4±0.4; p<0.001), need for aminergic support at 48 h after the procedure (-75.0%, p=0.006) and improvement in right ventricular function in 66.6% (p=0.008). Clinical success was 75.9%. Severe adverse event rate was 10.3%: two deaths during the procedure and one pulmonary macroembolization during device progression. In-hospital and three-month survival rates were 82.8% and 72.4%, respectively. Conclusions Aspiration thrombectomy for acute high- and intermediate-high-risk PE is feasible with a high technical and clinical success rate. Nevertheless, all-cause mortality is still high, probably related to the baseline high-risk features of the studied population and associated comorbidities.