Associazione Nazionale Medici Cardiologi Ospedalieri



Effectiveness and safety of half-dose thrombolysis in intermediate-high risk pulmonary embolism: a retrospective, single center experience

Zagarese Giorgia Verona(Verona) – Ospedale Civile Maggiore Borgo Trento | Santori Valentino Firenze(Firenze) – DiSIA Università degli Studi di Firenze | Giatti Sara Rovigo(Rovigo) – Ospedale Santa Maria della Misericordia

BACKGROUND: Current guidelines recommend full-dose systemic thrombolysis for acute

pulmonary embolism (PE) in high-risk or hemodynamically unstable intermediate-high risk (IHR-

PE) patients. Recent trials suggest that a low, half dose (50 mg) of tissue plasminogen activator

(HDrtPA) could be a safe, effective alternative with low bleeding risk. We aimed to evaluate

whether HDrtPA in IHR-PE could improve right heart function echocardiographic parameters and

NT-proBNP levels at discharge, in comparison to unfractionated heparin (UFH) alone.

METHODS: We retrospectively analyzed ninety IHR-PE consecutively admitted to our Intensive

Cardiac Care Unit between January 2016 and May 2023. HDrtPA patients (Group A, n=28) received

low-dose thrombolytic therapy (0,6 mg/kg, max. 50 mg in 1 hour) plus UFH. Group B included

patients were treated with UFH alone. Primary endpoint was an improvement between admission

and discharge of tricuspid annular plane systolic excursion (TAPSE), tricuspid velocity (TV), RV-

arterial coupling (TAPSE/PASP or pulmonary artery systolic pressure), basal right ventricle

diameter (RVD), and NT-proBNP levels. Secondary endpoint involved assessing the occurrence of

mortality and bleeding events. Linear regression models were used with Inverse Probability

Weighting propensity scores. Due to the low occurrence of death events, this endpoint was

investigated only through descriptive statistics.

RESULTS: Mean age was 73.48 ± 12.49 (mean ± Sd) and n=43 (47.8%) were males (table 1). Group A

had improvement of TAPSE/PASP (+0.16, p=0.006, CI 95%: 0.06; 0.27), RVD (-6 mm, p=0.001, CI

95%: -8.61; -3.58), TAPSE (+2.6 mm, p=0.003, CI 95%: 0.77; 4.49) and TV values (-0.46 m/s,

p=0.018, CI 95%: -0.8; 0.09), while the decrease in NT-proBNP values (-2048 pg/ml) did not achieve

statistical significance (p=0.382, CI 95%: -7101.17; 2413.45). No significant increase in major

bleedings was observed between groups (Group A: 3.5%, Group B: 0%) with an acceptable number

of minor bleedings (Group A: 25%, Group B: 1.6%). Death occurred in 3 patients in group A (10%)

and 1 patient in group B (1.6% – table 2).

CONCLUSIONS: In selected IHR-PE patients, administration of HDrtPA seems to improve right

ventricular function, dimensions and RV-arterial coupling in comparison to UFH alone, with an

acceptable bleeding and mortality risk. These results should be confirmed in randomized,

prospective trials to allow HDrtPA to be fully included in future guidelines.