Abstract
Thrombolytic therapy alleviates pulmonary embolism (PE) symptoms rapidly but increases bleeding risk, with no consistent consensus on acute intermediate-high risk PE. This study evaluated the efficacy and safety of low-dose prolonged infusion thrombolysis for acute intermediate-high risk PE to provide a safer clinical option. A total of 120 patients were collected and divided into anticoagulant (Group A, n = 58) and thrombolytic (Group B, n = 62) groups. Efficacy outcomes included pulmonary artery thrombus clearance rate, 30-day all-cause mortality, and 3-6 month pulmonary hypertension incidence; the primary safety outcome was treatment-related bleeding. Both groups showed improved SBP, DBP, SpO₂, and RV/LV ratio (all p < 0.05) with no inter-group differences, but Group B had higher thrombus clearance rate ([64.85 ± 17.47]% vs. [41.65 ± 16.19]%, p < 0.001), with similar 30-day mortality (1.61% vs. 5.17%, p = 0.278). At 1 day, post-treatment, Group B had higher D-dimer (26.78 ± 16.57 μg/mL vs. 7.60 ± 7.23 μg/mL) and FDP (91.45 ± 97.37 μg/mL vs. 18.60 ± 26.34 μg/mL, all p < 0.001) but comparable FIB (p = 0.091); these differences persisted until discharge (all p < 0.05 for D-dimer/FDP). Although the incidence of bleeding events in group B was numerically higher than that in group A (17.74% vs. 6.90%, p = 0.073), the difference between the two groups was not statistically significant. No fatal bleeding, intracranial hemorrhage, or recurrent pulmonary embolism occurred in either group. Group B had lower 3-6 month pulmonary artery systolic pressure (PASP) (30.70 ± 9.70 vs. 34.44 ± 10.04 mmHg, p = 0.045) and pulmonary hypertension incidence (27.87% vs. 54.55%, p = 0.004). Thrombus clearance rate correlated with treatment group (r = 0.57, p < 0.001), and D-dimer (r = 0.42) and FDP (r = 0.32) levels at 1 day post-treatment (both p < 0.001). Low-dose prolonged infusion can effectively clear pulmonary artery thrombi in patients with acute intermediate-high-risk PE, which may be associated with a reduced incidence of pulmonary hypertension. Patients in the thrombolysis group showed significant dynamic changes in D-dimer and FDP levels, which were significantly correlated with a higher thrombus clearance rate.