Post-thrombolytic coagulopathy and complications in patients with pulmonary embolism treated with fixed-dose systemic alteplase

Background Alteplase treatment can cause a systemic coagulopathy although the incidence and contributory factors are unknown in pulmonary embolism (PE). Fixed-dosing of alteplase for PE may lead to interpatient variability in drug exposure and influence post-thrombolytic coagulopathy (PTC). While changes in fibrinogen and INR have been used to describe PTC, no universal PTC definition is available. Objectives Evaluate the incidence of PTC after alteplase treatment for PE, the effect of patient weight and blood/plasma volume and the association with bleeding complications. Methods We conducted a retrospective cohort study of patients treated with alteplase for massive or high-risk submassive PE. Demographics, alteplase dosing, laboratory assessment of coagulopathy, and bleeding events were collected. The primary endpoint was incidence of PTC defined as an international normalized ratio (INR) > 1.5 or fibrinogen < 170 mg/dL. Secondary outcomes included correlation between coagulopathies and alteplase dose normalized to actual body weight (ABW), ideal body weight (IBW), plasma volume (PV), and estimated blood volume (EBV). Bleeding events in patients with and without PTC were compared. Results 125 patients met criteria for inclusion in the study. PTC occurred in 35.3% of patients, with INR >1.5 in 21.8% and fibrinogen <170 mg/dL in 26%. Alteplase dose >50 mg was associated with increased odds of PTC (OR 6.5, CI 2.1-19.9). Dose normalized to ABW and EBV correlated weakly with absolute increase in post-alteplase INR (r =0.20, p =0.06 and r =0.21, p =0.057 respectively) and to percent change in INR (r =0.20, p = 0.058 and r =0.21, p =0.048 respectively). Dose/ABW, dose/PV, and dose/EBV each correlated moderately with absolute decrease in fibrinogen (r =-0.53, -0.49, and -0.47 respectively, p <0.001 for each) and percent change in fibrinogen (r = -0.55, -0.49, and -0.49 respectively, p < 0.001 for each). Dose/IBW correlated weakly with absolute and percent decrease in fibrinogen (r = -0.32, p =0.013 and r =-0.33, p =0.011). Patients with bleeding were more likely to have PTC (58.3% vs. 28.6%, p= 0.05) and a bleeding event was predictive of PTC (OR 5.33, 1.32-23.99). Conclusions PTC is prevalent in patients with PE. PTC is influenced by alteplase dose and exposure parameters (ABW, IBW, PV, EBV) and may contribute to the bleeding risk.