High-risk pe patients eligible for both large-bore mechanical thrombectomy and systemic thrombolysis: insights from the FLASH and FLAME Studies
L Hobohm, C TomaAbstract
Background
High-risk pulmonary embolism (PE) is characterized by hemodynamic instability, and early mortality remains high under current guidelines that recommend first-line systemic thrombolysis (ST). Large-bore mechanical thrombectomy (LBMT) might improve outcomes of high-risk PE, but comparative data are scarce.
Purpose
In this combined analysis of two studies that enrolled patients with high-risk PE, the results of LBMT and ST are evaluated in a population that was medically and anatomically eligible to receive either thrombectomy or a lytic-based treatment.
Methods
The analysis included subjects with high-risk PE from the FLAME study (NCT04795167) and the FLASH study (NCT03761173), including both the US and European cohorts. These prospective, observational studies defined high-risk PE according to European Society of Cardiology guidelines. In this analysis, subjects eligible for LBMT are defined as those with central and/or lobar PE, and subjects eligible for ST are defined as those with no absolute or relative contraindication to lytic agents. In extremis indicates cardiopulmonary resuscitation on arrival for FLASH subjects and SCAI SHOCK Stage E for FLAME subjects.
Results
In a cohort of 257 high-risk PE subjects, 181 were eligible for both ST and LBMT. Of these, 136 (75.1%) subjects received primary LBMT, and 33 (18.2%) received primary ST. The primary treatment groups demonstrated similar baseline characteristics: The LBMT group was a mean age of 61.0±13.6 years and 50.7% female, and the ST group was a mean age of 59.1±14.4 years and 60.6% female. Body mass index was 33.7±8.2 kg/m2 and 34.6±9.0 kg/m2 in the LBMT and ST groups, respectively. Also, baseline vitals and imaging evidence were clinically similar: heart rates at presentation were 104.9±21.1 bpm (LBMT) and 108.5±28.8 bpm (ST), lowest systolic blood pressures, including subjects on vasopressors, were 100.3±25.7 mmHg (LBMT) and 93.8±32.1 mmHg (ST), and right ventricle/left ventricle ratios were 1.7±0.5 (LBMT) and 1.6±0.5 (ST). After reperfusion therapy, the in-hospital mortality rate was 2.2% (n=3) in the LBMT group and 27.3% (n=9) in the ST group. Comparing LBMT with ST, LBMT was associated with numerically lower rates of major bleeding (6.7% [n=9] vs. 24.2% [n=8]), clinical deterioration (5.9% [n=8] vs. 12.1% [n=4]), and bailout or adjunctive therapy use (3.7% [n=5] vs. 27.3% [n=9]). When excluding the 15 FLASH subjects and 14 FLAME subjects in extremis at baseline, the outcomes remained similar (Figure).
Conclusions
In this pooled high-risk PE cohort, favorable clinical trends were observed among patients who received LBMT as an alternative to ST. The observed data point toward the potential utility of LBMT as a primary intervention in patients with high-risk PE who can be safely transitioned to the interventional setting.For image description, please refer to the figure legend and surrounding text.