Safety, efficacy, and long-term outcomes of patients with severe pulmonary hypertension who undergo mechanical thrombectomy for pulmonary embolism: results from the FLASH registry
Purpose: Longer-term outcomes following mechanical thrombectomy (MT) in PE patients with severe pulmonary hypertension (PH) are poorly characterized. It is unknown if these patients receive equal benefit or are at higher risk of adverse events. We report 6-month outcomes following MT in PE patients with severe PH from the FLASH registry.
Materials and Methods: FLASH (NCT03761173) is a prospective, multicenter registry evaluating the safety and effectiveness of the FlowTriever System (Inari Medical, Irvine, CA) for treating intermediate- and high-risk PE patients. Severe PH was defined as systolic pulmonary artery pressure (sPAP) ≥70 mmHg measured by invasive hemodynamics prior to intervention. The primary endpoint was a composite of major adverse events (MAE) occurring within 48 hours. Patients were followed for 6 months post-thrombectomy.
Results: Of the 99 (12.6%) patients with severe PH, 83 completed the study with a mean follow-up time of 203.9 days. Disease severity included 92.9% (92/99) intermediate-risk and 7.1% (7/99) high-risk PE. Immediately following MT, average sPAP decreased from 78.9 to 60.9 mmHg (-22.4%, p< 0.0001) and 74.2% (72/97, p < 0.0001) of patients saw resolution of PH or a reduction in PH severity. Roughly one-third of patients (35.1%, 33/94) had a post-procedure overnight ICU stay for a median of 1.0 night [IQR: 1.0 – 2.0]. The MAE rate was 3.1% (3/97) through 48 hours. Important outcomes measured at follow-up are included in Table 1. Longer-term improvements in RV/LV ratio, RV systolic pressure (RVSP), and RV function were noted, indicative of sustained resolution of severe PH. Reductions in dyspnea, improvements in quality of life, and low rates of all-cause mortality, CTEPH, and CTED were also reported.
Conclusion: Results suggest a low MAE rate and lasting benefit for PE patients with severe PH treated with the FlowTriever System, similar to results from the broader FLASH population. Patients experienced improved hemodynamics, reduced functional limitations, and low rates of chronic complications at the 6-month visit.