OBJECTIVES: To investigate the association between the composite shock score (CSS) and immediate outcomes of mechanical thrombectomy (MT) in acute intermediate-risk pulmonary embolism (PE).
METHODS:A retrospective review was conducted of all patients undergoing MT for intermediate risk PE in our institution between 2020 and 2022.As previously described in the literature, the CSS was calculated based on 6 parameters - central thrombus burden, concomitant deep venous thrombosis, elevated troponin and BNP levels, tachycardia and right ventricle dysfunction - with a maximum score of 6. Subjects with missing information were excluded. Our primary outcome measure was post-procedure change in pulmonary artery systolic pressure (PASP).
RESULTS: The cohort consisted of 122 subjects, with a mean age of 64±15 years. 78% presented a simplified pulmonary embolism severity index (sPESI)>=1. The mean systolic blood pressure was 122±22 mmHg with tachycardia present in 46%. Forty-two subjects (35%) presented with saddle embolism, while elevated BNP and troponin were recorded in 54% and 85% respectively. The mean RV/LV ratio was 1.5±0.5 with right ventricle dysfunction in 86%. The composite shock score was a mean of 3.6±1.2 with 57% presenting a score >=4. The median procedure duration was 67 minutes, and the technical success rate was 95%. The procedure had to be aborted in 6 (5%) patients due to intraoperative cardiovascular collapse. The systolic PA pressure measured 54±15 mmHg at baseline and dropped to 35± 11 mmHg post-procedure (p<0.001). Perioperative adverse events were recorded in 10 patients (8%) with mortality occurring in 4 (3%). The CSS of patients presenting with perioperative events was not significantly different from their counterparts (3.4±1.3 vs 3.7±1.3, p>0.05). Of note, patients with CSS>=4 tended to present greater improvement in PA pressure (PASP reduction of -19±11mmHg vs -13±11 mmHg; p =0.048).
CONCLUSIONS: Our limited series signals a trend toward greater PA pressure improvement after mechanical thrombectomy in patients presenting a composite shock score >=4. Larger studies are required to further investigate this association and determine the role of the CSS in patient selection 
