22-05-2025
Quick Turn to Mechanical Thrombectomy Improves PE Outcomes
Patients with pulmonary embolism (PE) who were treated with mechanical thrombectomy (MT) within 12 hours of hospital admission had significantly better pulmonary outcomes than patients treated with mechanical thrombectomy more than 12 hours after admission, based on new data from the FLASH registry.
The benefits of prompt treatment with MT for patients with high-risk PE are evident, but data on the impact of MT timing on outcomes in patients with intermediate-risk PE are limited, wrote Krunal Patel, MD, and Parth M. Rali, MD, of the Lewis Katz School of Medicine, Temple University Hospital, Philadelphia, in a study presented at the American Thoracic Society (ATS) 2025 International Conference in San Francisco.
The FLASH registry is a prospective, multicenter registry of patients with acute intermediate-risk and high-risk PE who were followed for 6 months after treatment with a large-bore aspiration MT system, the authors wrote.
'The safety of mechanical thrombectomy has been established through the FLASH study, but as more centers adopt advanced interventions such as MT and catheter-directed thrombectomy, it is critical to determine the optimal timing for these procedures,' Patel said in an interview. 'Understanding when to intervene could significantly impact outcomes for patients with pulmonary embolism,' he said.
The researchers classified 726 patients with intermediate-risk PE into two groups: Short time to MT (short TtMT, defined as 12 hours or less) and long time to MT (long TtMT, defined as more than 12 hours).
The short TtMT group included 215 patients with a median time of 6.12 hours to treatment, and the long TtMT group included 511 patients with a median of 24.78 hours to treatment. Patients were assessed for outcomes including mean pulmonary artery pressure (mPAP) and systolic pulmonary artery pressure (sPAP), as well as right ventricle to left ventricle (RV/LV) ratio, distance on the 6-minute walk test, and Pulmonary Embolism Quality of Life score.
At baseline, patients in the short TtMT group had a higher lactate and higher RV/LV ratio than those in the long TtMT group.
Both mPAP and sPAP reductions were significantly greater in the short TtMT group vs the long TtMT group (9.0 mm Hg vs 7.0 mm Hg and 14.0 mm Hg vs 12.0 mm Hg, respectively; P < .0001 for both).
Patients in the short TtMT group also had greater reductions in RV/LV ratios from baseline to follow-ups of 48 hours, 30 days, and 6 months than those in the long TtMT group. The short TtMT group also had a significantly longer median distance on the 6-minute walk test at the 6-month follow-up visit than the long TtMT group (450.5 m vs 390.0 m; P = .0260). No differences in safety events including major bleeding through 48 hours and mortality at 30 days were observed between the groups.
Revised Guidance Needed
'We suspected, much like with [ST-elevation myocardial infarction] STEMI and stroke, that the principle of 'time is tissue' would apply, meaning that earlier intervention would lead to better outcomes,' Patel told Medscape Medical News . 'We focused solely on intermediate-risk PE patients to limit confounding from illness severity, and we observed meaningful clinical improvements in the early group,' he said.
One major barrier to the rapid initiation of MT following hospital admission is that current guidelines haven't kept pace with emerging interventional strategies, Patel told Medscape Medical News . 'Broad adoption requires consensus and updated protocols,' he said. 'Implementing a Pulmonary Embolism Response Team (PERT) can also be pivotal in streamlining patient evaluation and ensuring timely access to advanced therapies,' he noted.
'A prospective trial would provide the strongest evidence but may be challenging in high-risk patients, where most clinicians already agree on the need for rapid intervention, and in the meantime, we rely on retrospective data,' said Patel. 'More importantly, we need to revise how we classify PE patients,' he said. A modern classification system should integrate multiple therapies including MT into the risk stratification framework, Patel said.
'Globally, a patient dies of a PE every minute, and with advanced interventions this will hopefully become a thing of the past, but more focus needs to be taken on timing and developing a new way of classifying patients so interventions can take an algorithmic approach incorporating these new treatment modalities,' he said.
Data May Drive Increased Use of Technology
'The treatment of intermediate-risk pulmonary embolism is one of the clinical areas where there is wide variability because the data we have leaves room for interpretation,' said Anthony Faugno, MD, a pulmonologist at Tufts Medicine, Boston, in an interview.
Not every center has advanced invasive capabilities for MT, he noted. 'More clarity on the benefits of these invasive therapies will help individual centers identify the need to adopt these technologies and build systems for their best use,' Faugno said.
Regarding the current study, 'Being that this was a registry and not a randomized controlled trial, it is likely that the patients in the early intervention group were recognized as being clinically sicker, resulting in faster treatment,' Faugno told Medscape Medical News . The baseline differences in RV/LV ratio and lactate support that a sicker group received earlier intervention, and one would expect their hemodynamics to benefit more, he said. 'It is surprising that the sicker initial group had enhanced quality of life at follow-up, but it is hard to draw conclusions about this without an understanding of the different comorbidities in each group,' he noted.
Because the current study did not adjust for factors such as chronic medical illness that might affect patient function at 6 months, the results should be interpreted with some caution, Faugno noted. However, more data such as these may prompt more centers to rapidly mobilize the resources needed for invasive procedures in cases of intermediate-risk PE, he said.
As for additional research, 'I think the most important clinical question in the intermediate-risk pulmonary embolism group is deciding who can be treated with systemic anticoagulation alone and who benefits from the invasive, and sometimes costly, procedures,' Faugno told Medscape Medical News . 'There are some centers, specifically small and rural hospitals, that will be unable to provide advanced invasive treatments at all hours,' he noted. 'I think there is still a benefit to noninvasive treatment of intermediate-risk pulmonary embolism in the properly selected patient; research to understand who these patients are will help us develop future clinical trials on treatments,' he said.
The study received no outside funding.
