HI-PEITHO Analysis Studies Predictors of Major Bleeding in Acute Intermediate-Risk PE

October 16, 2026—A post hoc analysis of the randomized HI-PEITHO study examined potential predictors of major bleeding in patients with acute intermediate-risk pulmonary embolism (PE) treated with ultrasound-facilitated catheter-directed thrombolysis (USCDT) using the Ekos endovascular system (Boston Scientific Corporation) plus anticoagulation (AC) or anticoagulation (AC) alone.

The analysis identified four variables with significant main or interaction effects on major bleeding risk: cancer, right ventricular/left ventricular (RV/LV) ratio, baseline National Early Warning Score (NEWS), and sex.

The findings were presented by Michael N. Young, MD, at VIVA 2026, the Vascular InterVentional Advances conference.

According to the VIVA summary of the presentation, the HI-PEITHO study demonstrated a reduced risk of defined clinical outcomes with USCDT using Ekos plus AC compared with standard-of-care AC alone, without an excess risk of major bleeding.

The post hoc analysis assessed potential predictors of major bleeding in the entire study cohort. Major bleeding was defined according to International Society on Thrombosis and Haemostasis criteria, as determined by a blinded clinical events committee, and assessed within 30 (+7) days of randomization in the intention-to-treat cohort.

VIVA further reported that overall major bleeding was low, with no significant difference between the USCDT and AC-only groups (4% vs 3%; two-sided P = .64). No intracranial hemorrhage occurred in either group.

Investigators used univariable and multivariable logistic regression to assess predictors of major bleeding. Of the four variables identified in multivariable analysis (P < .05), NEWS < 7 was associated with reduced major bleeding risk among patients treated with USCDT, whereas cancer and RV/LV ratio ≥ 1.5 were associated with increased risk among patients treated with AC alone. The other 20 variables assessed did not independently affect major bleeding.

According to the analysis presented at VIVA, baseline factors differentially impact major bleeding risk in patients treated with USCDT or AC alone.

The HI-PEITHO data were presented in a late-breaking science session at ACC.26, the American College of Cardiology’s annual scientific session. The study findings were simultaneously published by Kenneth Rosenfield, MD, et al in The New England Journal of Medicine.