Comparison of half-dose alteplase and LMWH in intermediate-high risk pulmonary embolism: a single-center observational study.

Background And Aim: The use of thrombolytics in intermediate-high risk pulmonary embolism (PE) remains controversial. This study evaluated the efficacy and safety of half-dose alteplase compared to anticoagulation with LMWH in this group.

Material And Methods: Patients treated with thrombolytics (50 mg alteplase) after the establishment of EGEPET (2.10.2018) formed the prospective group, while the retrospective group included patients treated with LMWH (enoxaparin) before EGEPET. Primary outcomes were one-month and one-year mortality. Secondary outcomes were vital sign changes after thrombolysis, hemorrhagic events, recurrence of embolism, chronic pulmonary thromboembolism (CPTE), and chronic thromboembolic pulmonary hypertension (CTEPH).

Results: Thrombolytic group (n = 59) and anticoagulation group (n = 38) were similar in age, comorbidities, and vital signs, except for higher pulse rates in the thrombolytic group. In the thrombolytic group, PaO₂/FiO₂ ratio significantly improved [330 (270-380) to 417 (351-447), p < 0.001], and pulse rate decreased [116 (105-127) to 91 (80-104), p < 0.001]. In the anticoagulation group, oxygenation showed no significant change, but pulse rate improved. No major bleeding occurred in either group. One-month mortality was 6.7% in the thrombolytic group and 15.8% in the anticoagulation group (p = 0.18). One-year mortality was 13.7% and 26.3%, respectively (p = 0.17). Advanced age (> 67) (OR: 8.82, %95 CI 1.54 - 50.53 p = 0.014) and elevated second-day pulse > 94/min (OR 7.61, 95% CI 1.33-43.49, p = 0.022) were independent predictors of one-month mortality in the multivariate analysis.

Conclusion: Thrombolytic therapy significantly improved oxygenation and clinical findings without major complications. Although mortality rates were lower in the thrombolytic group, the difference was not statistically significant. These results should be interpreted with caution, and larger prospective studies are needed to confirm the clinical efficacy and safety of thrombolytic therapy in this patient population.