CICU Director NYU Grossman School of Medicine New York, New York, United States
Objective: Acute mortality rates for high-risk pulmonary embolism (PE) are ~30% even when treated with advanced therapies, including the current standard of care, systemic thrombolysis. Percutaneous mechanical embolectomy offers an alternative approach to PE treatment, but data regarding its use in high-risk patients are limited. This subanalysis of the FLASH registry assessed the safety and effectiveness of the FlowTriever System (Inari Medical, Irvine, CA) for treating patients with high-risk PE.
Methods: The prospective, multicenter FLASH registry (NCT03761173) has completed US enrollment of real-world PE patients, including patients with intermediate- and high-risk PE as defined by current ESC guidelines. Baseline and procedural characteristics were collected, and prespecified acute outcomes through 30d were evaluated. An independent medical monitor adjudicated adverse events (AEs), including major adverse events (MAEs) of device-related mortality, major bleeding, or intraprocedural device- or procedure-related AEs.
Results: Of 800 PE patients in the US cohort of FLASH, 63 (7.9%) were classified as high-risk. In this cohort, the mean age was 59.4±15.6 years, 34 (54.0%) patients were women, and 16 (25.4%) patients were contraindicated for thrombolysis. Among patients with baseline data available, 18 (54.5%) demonstrated elevated lactate ≥2.5 mM, 21 (42.9%) were in cardiogenic shock (cardiac index [CI] < 2 L/min/m2), 22 (34.9%) required vasopressors, and the highest heart rate was 120.5±20.8 bpm. Post embolectomy, immediate hemodynamic improvements were observed: mean pulmonary artery pressure decreased from 31.5±9.7 to 24.3±9.6 mmHg (-22.6% mean change, P < 0.0001), and CI increased from 1.5±0.2 to 1.9±0.6 L/min/m2 (26.5% mean change, P < 0.0001) for patients in cardiogenic shock at baseline. At 48h, there were no MAEs (Table 1). All patients survived to 48h, and no mortalities occurred in the 57 (90.5%) patients followed through 30d. RV function and mMRC dyspnea scores improved significantly at 48h and through 30d (Figure 1). Median PEmb-QoL Frequency of Complaints scores also improved from 15.6 [IQR 6.3–31.3] at 48h to 0.0 [IQR 0.0–6.3] at 30d (P=0.0010).
Conclusions: In high-risk PE patients, there were no mortalities through 30d or MAEs after mechanical embolectomy with the FlowTriever System. High-risk patients demonstrated significant improvement of acute hemodynamics and functional outcomes. Results from the FLASH registry suggest mechanical embolectomy is safe and effective for high-risk PE, leading to markedly lower acute mortality compared to previously reported mortality rates for this population.