Outcome of Large-Bore Thrombektomy versus conventional therapy in a real life Analysis of a multicentric intermediate-high- and high-risk cohort

Background:
Despite promising efficacy and safety results of catheter-directed treatment in small clinical trials, first-line treatment for patients with acute pulmonary embolism (PE) remains systemic anticoagulation and/or fibrinolysis. Real life outcome data comparing interventional with conventional (CON) treatment, especially involving high-risk PE is still scarce. Particularly in hemodynamically compromised patients, a fast reperfusion might directly impact clinical and right ventricular (RV) burden, translating into better survival. Large-bore Thrombectomy devices like Flowtriever (FT) provide such fast relief of thrombotic mass. We aimed to compare the effects of Flowtriever vs. conventional therapy on immediate clinical and echocardiographical improvement as well as mortality in a multi-center cohort of patients with intermediate-high/high-risk PE.

Methods:
We retrospectively compared data from all intermediate-high- and high-risk PE patients who underwent either conventional therapy or FT-treatment at one of 7 German centres with cases dating between 2019 and 2023. Patients in the FT group and the CON group were compared by baseline characteristics, clinical and laboratory parameters, as well as PESI-score and echocardiographic parameters.

Results:
488 patients (age 69±14 y, 60% male) were included in ouranalysis, 239 in the conventional treatment group (43 high-risk, 196 intermediate-high-risk, with 40%  vs. 4% receiving systemic thrombolysis) and 249 in the FT group (52 high-risk, 197 intermediate-high-risk).

Baseline characteristics and relevant comorbidities were matched between subgroups with few differences (Table1). In the intermediate-high risk cohort PESI score was higher for FT-group (114±32 vs. 92±28, p<0.001), RV/LV-ratio was comparable (p=0.77).

Clinical parameters and RV/LV-ratio significantly improved in both treatment arms and all subgroups (all p<0.01), while changes in TAPSE and sPAP were only significant for the FT group (resp. CON vs. FT p= 0.38 vs. p<0.001; p=0.87 vs. p=0.01).

Lactate was significantly reduced at 24 hours after FT-treatment within the high-risk group (p<0.001), while lowering for high-risk CON were not significant (p=0.44).

All-cause in-hospital mortality turned out lower for FT within all the subgroup analyses (resp. CON vs. FT; all: 15.6 vs. 3.7%, p<0.001; High: 51.2 vs. 13.5%, p<0.001; Int-High: 5.8 vs. 1.0 %, p= 0.01).

Conclusion:
Patients with high-risk PE undergoing treatment via FT demonstrated fast and significant clinical, laboratory and echocardiographic improvement, which subsequently translated into improved survival outcomes, when compared to conventional treatment. These benefits also extended to the intermediate-high-risk cohort. The results further support a beneficial effect of large-bore thrombectomy as a treatment option for acute PE but warrant confirmation in prospective trials.