Efficacy and Safety of Low Dose rt-PA for the Treatment of Acute Pulmonary Thromboembolism: A Randomized, Multi-Center, Controlled Trial.

Author(s): Wang C, Zhai Z, Yang Y, Wu Q, Cheng Z, Liang L, Dai H, Huang K, Lu W, Zhang Z, Cheng X, Shen YH, For China Venous Thromboembolism(VTE) Study Group

Affiliation(s): 1 Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.

Publication date & source: 2009-09-09, Chest., [Epub ahead of print]

Publication type:

BACKGROUND: Optimal dosing of the recombinant tissue-type plasminogen activator (rt-PA) is important in treating pulmonary thromboembolism (PTE). The aim of this study was to compare the efficacy and safety of rt-PA 50mg/2h regimen with 100mg/2h regimen in acute PTE patients. METHODS: A prospective, randomized, multicenter trial was conducted. 118 acute PTE patients with either hemodynamic instability or massive pulmonary artery obstruction were randomly assigned to receive either rt-PA 50mg/2h (n=65) or 100mg/2h (n=53) treatment. The efficacy was determined by the improvements of right ventricular (RV) dysfunctions on echocardiogram, the lung perfusion defects on V/Q scan and pulmonary artery obstructions on CT angiograph. The adverse events including death, bleeding and PTE recurrence were also evaluated. RESULTS: Progressive improvements in RV dysfunctions, lung perfusion defects and pulmonary artery obstructions were found to be similarly significant in both treatment groups. This is true for patients with either hemodynamic instability or massive pulmonary artery obstruction. Three (6%) patients in the rt-PA 100mg/2h group and one (2%) in the rt-PA 50mg/2h group died due to either PTE or bleeding. Importantly, 50mg/2h rt-PA regimen had less bleeding tendency than the 100mg/2h regimen (3% vs.10%), especially in patients with body weight less than 65 kg (14.8% vs. 41.2%, P=0.049). No fatal recurrent PTE was found in either group. CONCLUSIONS: Compared with the 100mg/2h regimen, 50mg/2h rt-PA regimen exhibits similar efficacy and perhaps better safety in acute PTE. These findings support the notion that optimizing rt-PA dosing is worthwhile when treating the PTE patients.