Introduction: Mortality in high-risk pulmonary embolism (PE) patients remains high. Systemic thrombolysis (ST) is the guideline-recommended treatment, but high bleeding risks limit its use, and comparative studies of alternative treatments such as mechanical thrombectomy (MT) are lacking. This study combined data from 2 high-risk PE studies to evaluate treatment-specific outcomes in patients eligible for either ST or MT.
Methods: The FLAME study (NCT04795167) and the FLASH registry (NCT03761173) are prospective, observational studies that enrolled high-risk PE patients. The US cohort of FLASH enrolled 63 high-risk PE patients treated with MT using the FlowTriever System. FLAME enrolled 53 high-risk PE patients treated with MT using the same device and 61 high-risk PE patients treated with other non-MT therapies. Outcomes were pooled across the studies and assessed in the subset of patients who were medically and anatomically eligible to receive thrombolysis and MT. This dual eligibility was defined as the absence of absolute or relative contraindications to lytic agents and the presence of central and/or lobar PE.
Results: Of the 177 patients with high-risk PE from the 2 studies, 69.5% (n=123) were eligible for both thrombolysis and MT. Of these, MT was used in 63.4% (n=78), while ST was used in 26.8% (n=33). The remaining 9.8% (n=12) received anticoagulation alone or other therapies. Baseline heart rates were 107.1±22.0 bpm (MT) and 108.5±28.8 bpm (ST). Lowest systolic blood pressures were 93.9±20.5 mmHg (MT) and 93.8±32.1 mmHg (ST). Right ventricle/left ventricle ratios were 1.7±0.4 (MT) and 1.6±0.5 (ST). Adverse outcomes were less frequent in patients receiving MT treatment. Acute mortality was 1.3% (MT, n=1) and 27.3% (ST, n=9). Major bleeding occurred in 6.4% (MT, n=5) and 24.2% (ST, n=8). Clinical deterioration occurred in 5.1% (MT, n=4) and 12.1% (ST, n=4). Finally, bailout or adjunctive therapy use occurred in 5.1% (MT, n=4) and 27.3% (ST, n=9).
Conclusions: Pooled data from 2 prospective studies of high-risk PE show favorable outcomes in patients who were treated with MT despite being eligible for ST, with low rates of mortality, clinical deterioration, major bleeding, and therapy escalation. These data support MT as frontline therapy in high-risk PE patients.
