LAUSR

Acute pulmonary embolism (PE) is a significant cause of cardiovascular morbidity and mortality and requires prompt diagnosis and treatment. Early diagnosis and management are paramount as most deaths from acute PE occur within the first several hours to days: 30‐day mortality rate is approximately 16% and raises up to 30% in high‐risk PE. The rationale for prompt treatment in massive PE is to avert impending hemodynamic collapse and death from progressive right‐sided heart failure. The ideal treatment for PE patients at risk for progressive decompensation is controversial because of the lack of trials of adequate size with a focus on this patient population. In patients with acute PE, regardless of its severity, parenteral anticoagulation is recommended unless contraindicated. Systemic or catheter‐directed infusion of thrombolytics is considered the cornerstone therapy in patients with massive and submassive PE who subsequently deteriorate despite anticoagulation. The recent Pulmonary Embolism Thrombolysis (PEITHO) study is the largest randomized controlled trial of systemic fibrinolysis in PE to date, enrolling 1006 patients with intermediate‐risk PE, randomly assigned to bolus tenecteplase or placebo. Patients treated early with thrombolytics had less hemodynamic deterioration compared to anticoagulation alone: systemic fibrinolysis reduced the frequency of the primary outcome, consisting of death or hemodynamic decompensation at 7 days of randomization (2.6% vs. 5.6%, p = 0.015), with most of the benefit due to a reduction in hemodynamic collapse within 7 days (1.6% vs. 5%, p = 0.002). However, the benefit of fibrinolysis came at the cost of an increased major bleeding rate (6.3% vs. 1.5%, p < 0.001), with about 2% of the tenecteplase‐treated patients suffering an intracranial hemorrhage. Therefore, concern over the risk of major and potentially fatal bleeding has sparked the development of alternative fibrinolytic strategies with lower bleeding risk. In this issue of Catheterization and Cardiovascular Interventions, Toma et al. provide interesting insights into the safety and effectiveness of percutaneous mechanical thrombectomy using the current FlowTriever System in a broader real‐world setting, including both intermediate‐risk and high‐risk PE patients. The FlowTriever system (Inari Medical) is a device that mechanically engages thrombus via self‐expanding nitinol disks and then aspirates trapped thrombus. In the FLARE, a single‐arm, multicenter study of 106 patients with intermediate‐risk PE, embolectomy with the FlowTriever system resulted in a 25% reduction in CT‐measured right ventricle (RV)‐to‐left ventricle (LV) ratio (mean difference: 0.38; p < 0.0001) and 10% decrease in mean modified Miller index (mean difference: 1.90; p < 0.001). Anyway, the FLARE study was performed using the first‐generation FlowTriever System, enrolling only intermediate‐risk PE patients, and outcome measures were limited to surrogate measures of clinical outcomes. As commendably reported by the authors, the FLASH prospective multicenter registry enrolled 250 patients with acute high‐risk massive (6.8%) or intermediate‐risk submassive (93.2%) PE treated by percutaneous thrombectomy. Safety outcomes in this real‐world population were favorable, with a low (1.2%) major adverse events (MAE) rate and no deaths through 48 h. All MAEs were major bleeds, but none were intracerebral hemorrhages and resolved without sequelae. The 4.4% of patients received adjunctive thrombolytics; all major bleedings occurred in patients who recently underwent other interventions or received thrombolytics. There were no other intraprocedural device or procedure‐related adverse events; all‐ cause mortality was 0.4% at 30 days, with a single death that was unrelated to PE. Moreover, percutaneous mechanical thrombectomy resulted in immediate hemodynamic improvements including an average reduction in mean pulmonary artery pressure of 7.1 mmHg (22.2%, p < 0.001); symptom reduction (dyspnea scores decreased significantly from 2.9 ± 1.1 pre‐procedure to 1.4 ± 1.3 at 48 h, p < 0.001), and cardiac function recovery (cardiac index significantly improved by 13.3% on‐table from 1.7 ± 0.2 to 1.9 ± 0.4 L/min/m, p = 0.005). In addition, RV systolic dysfunction grades and RV dilatation grades showed significant improvement at a median follow‐up of 32 days. In patients with paired measurements, percutaneous mechanical thrombectomy resulted in a 28% reduction in RV‐to‐LV ratio (RV/LV ratio mean difference: 0.36; p < 0.0001) and 35.8% decrease in RV systolic pressure (mean difference: 19.1mmHg, p < 0.001). Conversely, a systematic approach to PE patients at risk for hemodynamic deterioration and progressive decompensation is lacking and controversial. Heterogeneity of clinical presentation, rapidly advancing technology for device therapy, limited high‐quality comparative data regarding advanced therapies, and a number of evidence‐based clinical practice guidelines with varying recommendations for patients with intermediate‐high‐risk PE have established acute PE as one of the most challenging cardiovascular disorders in clinical practice. As proposed by Dudzinski et al. a multidisciplinary pulmonary embolism response team (PERT), which combines expertise from interventional cardiology, interventional radiology, cardiac surgery, cardiac imaging, can aid in the selection of appropriate management strategies, especially where gaps in