The ULTIMA study is intended to prove that in patients with pulmonary embolism and a right ventricular end diastolic diameter to left ventricular end diastolic diameter ratio ≥1 (RV/LV ratio) will benefit from treatment with ultrasound accelerated thrombolysis (rt-PA) as compared to unfractionated heparin anticoagulation. Specifically, at 24 hours the RV/LV ratio will be significantly reduced in the treatment arm compared to the control arm.
BACKGROUND: In patients with acute pulmonary embolism, systemic thrombolysis improves right ventricular (RV) dilatation, is associated with major bleeding, and is withheld in many patients at risk. This multicenter randomized, controlled trial investigated whether ultrasound-assisted catheter-directed thrombolysis (USAT) is superior to anticoagulation alone in the reversal of RV dilatation in intermediate-risk patients.
METHODS AND RESULTS: Fifty-nine patients (63±14 years) with acute main or lower lobe pulmonary embolism and echocardiographic RV to left ventricular dimension (RV/LV) ratio ≥1.0 were randomized to receive unfractionated heparin and an USAT regimen of 10 to 20 mg recombinant tissue plasminogen activator over 15 hours (n=30; USAT group) or unfractionated heparin alone (n=29; heparin group). Primary outcome was the difference in the RV/LV ratio from baseline to 24 hours. Safety outcomes included death, major and minor bleeding, and recurrent venous thromboembolism at 90 days. In the USAT group, the mean RV/LV ratio was reduced from 1.28±0.19 at baseline to 0.99±0.17 at 24 hours (P<0.001); in the heparin group, mean RV/LV ratios were 1.20±0.14 and 1.17±0.20, respectively (P=0.31). The mean decrease in RV/LV ratio from baseline to 24 hours was 0.30±0.20 versus 0.03±0.16 (P<0.001), respectively. At 90 days, there was 1 death (in the heparin group), no major bleeding, 4 minor bleeding episodes (3 in the USAT group and 1 in the heparin group; P=0.61), and no recurrent venous thromboembolism.
CONCLUSIONS: In patients with pulmonary embolism at intermediate risk, a standardized USAT regimen was superior to anticoagulation with heparin alone in reversing RV dilatation at 24 hours, without an increase in bleeding complications.
CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01166997.
The ULTIMA study is intended to prove that in patients with pulmonary embolism and a right ventricular end diastolic diameter to left ventricular end diastolic diameter ratio ≥1 (RV/LV ratio) will benefit from treatment with ultrasound accelerated thrombolysis (rt-PA) as compared to unfractionated heparin anticoagulation. Specifically, at 24 hours the RV/LV ratio will be significantly reduced in the treatment arm compared to the control arm.
