Catheter clot removal was tied to lower 1- and 2-year death rates in 4,268 patients with lung clots

A pooled analysis of 12 studies covering 4,268 patients with pulmonary embolism, the lung clots that block arteries feeding the lungs, found that catheter-based mechanical thrombectomy was associated with lower death rates at 30 days, one year and two years than anticoagulant drugs alone. Of those patients, 1,878, or 44%, had the procedure. Mahmoud Ismayl, an interventional cardiology fellow and assistant professor at Mayo Clinic, presented the work at TCT 2026.

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Twelve studies and 1,878 thrombectomy patients

The analysis is a systematic review and meta-analysis titled “Mechanical Thrombectomy Versus Anticoagulation Alone for Intermediate-Risk Pulmonary Embolism,” published Nov. 1 in the Journal of the Society for Cardiovascular Angiography and Interventions (DOI 10.1016/j.jscai.2026.105753). It was presented at the Transcatheter Cardiovascular Therapeutics meeting the same day. Thrombectomy means pulling or suctioning the clot out through a catheter threaded into the blood vessels, while the comparison group received blood thinners to keep clots from growing.

The Society for Cardiovascular Angiography and Interventions release reports that thrombectomy was associated with lower 30-day, 1-year and 2-year mortality in the primary analysis. It was also tied to a lower risk of chronic thromboembolic pulmonary hypertension, or CTEPH, a long-term complication in which clots leave scarring that raises pressure in the lung arteries. The release does not publish the pooled mortality rates, hazard ratios or confidence intervals, so the size of the gap is not available from the summary.

Intermediate-risk pulmonary embolism sits between the minor cases that blood thinners handle routinely and the life-threatening ones that call for emergency clot-busting treatment. Patients are stable, yet imaging or blood markers can show strain on the right side of the heart. That gray zone is where doctors disagree about whether to add a catheter procedure to medication. The abstract was assigned number TCT 1431 and presented at Station 1 on the meeting floor, and the media contact for the Society for Cardiovascular Angiography and Interventions was Gavin Stern.

The sensitivity analysis and the one-study problem

A second pass restricted to studies that enrolled only intermediate-risk patients changed the picture, as News-Medical’s account lays out. Thirty-day mortality came out similar between the two groups, so the early advantage did not hold. One-year and two-year mortality could not be pooled in that narrower analysis because each had been reported by only a single study. The reduction in CTEPH risk did remain statistically significant.

Ismayl said most of the available evidence is observational, and that larger randomized trials are needed to confirm the findings and determine which patients are most likely to benefit.

The caution matters. In observational data, doctors tend to choose thrombectomy for patients they judge fit for it, and those patients may differ from the ones kept on anticoagulants in ways a pooled analysis cannot fully remove. An association between the procedure and survival is the finding; proof that the procedure produces the survival is not.

Earlier analyses and a randomized trial

The HMP Global cath-lab posting repeats the same top-line numbers, which confirms the 44% share and the primary-analysis findings. An earlier and smaller pooled study, described by SOLACI, covered seven studies, one randomized and six observational, with 2,699 patients. It found lower 30-day mortality with thrombectomy (odds ratio 0.09, 95% confidence interval 0.02 to 0.41) but no significant difference in hospital deaths, and its authors flagged low event counts.

SOLACI’s summary adds that the devices in those studies included FlowTriever, Indigo and Lightning, and that thrombectomy was usually chosen for patients with a higher clot burden or hemodynamic risk, or where clot-dissolving drugs were undesirable, instead of by a uniform protocol. Length of stay in hospital and in intensive care showed no significant difference. In other words, the groups were often chosen for different reasons, which is the central weakness of pooled observational data and the reason the survival signal is treated as a hypothesis.

The strongest randomized evidence measures something else. STORM-PE enrolled 100 stable patients with intermediate-high-risk embolism and right heart strain. More thrombectomy patients had fully normal right heart function at 48 hours, and at 90 days they walked 472 meters in six minutes against 376 meters for the anticoagulation-only group. Death was not its endpoint.

STORM-PE used the Penumbra computer-assisted vacuum thrombectomy system and was presented at TCT 2025 and published in Circulation. Its secondary results also showed a lower average heart rate (80 against 86.4 beats a minute), less supplemental oxygen at 48 hours, and no device- or procedure-related adverse events. Robert Lookstein, M.D., of the Icahn School of Medicine at Mount Sinai and president of the Society of Interventional Radiology, was interviewed about it. A 100-patient trial cannot settle a question about death, which needs far more people.

The gap is therefore specific. Randomized work shows faster recovery of heart function, observational pooling shows fewer deaths at one and two years, and no randomized trial yet connects the two. Ismayl’s call for larger trials is the next evidence this field is waiting on.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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