551 - Large-bore Mechanical Thrombectomy vs. Intravenous Thrombolysis for Intermediate-high Risk Pulmonary Embolism: A 5-year Retrospective Analysis

Monday, April 13, 2026

12:10 PM - 1:10 PM ET

Poster Presenter(s)

PB

Patrick Barrett

Medical Student
Larner College of Medicine at the University of Vermont, United States

Author/Co-author(s)

JB

Jessica Badlam, MD

Pulmonologist
University of Vermont Medical Center, United States
KA

Katherine Acosta, MD

Pulmonary and Critical Care Medicine Fellow
University of Vermont Medical Center, United States
MA

Mary Ellen Antkowiak, MD

Pulmonary and Critical Care Physician
University of Vermont Medical Center, United States
GS

Geoffrey Scriver, MD

Associate Professor
University of Vermont Medical Center, United States
CM

Christopher Morris, Division of Interventional Radiology, University of Vermont Medical Center

Professor of Radiology and Surgery at the Larner College of Medicine at the University of Vermont
Division of Interventional Radiology, University of Vermont Medical Center, United States
JK

Joshua Kallen, MD

Associate Professor
UVM Medical Center, United States
AM

Alan R. Massouh, MD

Resident, Interventional Radiology, Integrated
University of Utah, United States
AB

Anant Bhave, MD

Associate Professor
University of Vermont Medical Center, United States
JS

Joseph Shields, MD

Associate Professor
University of Vermont Medical Center, United States
Bill Majdalany, MD, FSIR (he/him/his)

Associate Professor
University of Vermont Medical Center, United States

Purpose: To compare safety and efficacy of large-bore mechanical thrombectomy (LBMT) with intravenous thrombolysis (IVT) in the treatment of intermediate-high risk pulmonary embolism (PE).

Materials and Methods: An IRB approved, retrospective search for patients treated with LBMT or IVT for PE at a single institution from October 2020-June 2025 was performed. Inclusion criteria were intermediate-high risk PE determined by the Pulmonary Embolism Response Team (PERT) and intervention with LBMT and/or IVT. Exclusion criteria were contraindication for LBMT or IVT and hemodynamic instability. LBMT was performed with the Flowtriever System (Inari Medical, Irvine, CA) and anticoagulation. For IVT, 50 mg of tissue plasminogen activator (tPA) was administered under protocol with anticoagulation. Demographics, clinical data, imaging and outcomes were collected. Continuous variables were summarized as mean ± SD or median, and categorical variables as counts and percentages. Binary outcomes were compared with Fisher’s exact test, continuous variables with the Wilcoxon rank-sum test, and outcomes by change scores (post – pre) using the same test.

Results: 119 patients were included. 65 (54.6%, 31M/34F) received LBMT and 54 (45.4%, 29M/25F) received IVT. The average age of LBMT patients was 68.9 (± 12.5 years) and of IVT patients was 55.8 (± 17.3 years) (p < 0.05). Five IVT patients did not improve and required LBMT. Major bleeding complications occurred in five patients (4.2%), four in the IVT and one in the LBMT cohorts (p > 0.05). One patient passed away within 30 days and a single readmission occurred within six months, neither was statistically significant (p > 0.05). Mean ICU stay was 1.44 and 1.21 days for LBMT and IVT, respectively. Median ICU stay was one day for both groups. Hospital length of stay had a median of 3 days for both groups, LBMT patients had a tighter IQR with fewer prolonged stays, while IVT patients had a wider spread and more extended hospitalizations (p < 0.05). Echocardiography pre and post treatment revealed that right ventricular (RV) dilation and systolic function improved significantly more in LBMT patients compared with IVT patients (p < 0.05).

Conclusion: LBMT had significantly shorter hospital stays and greater improvement in RV dilation and systolic function compared with IVT, despite LBMT patients being significantly older.