Acute Pulmonary Embolism Trial Confirms Safety and Efficacy of Ultrasound Accelerated Endovascular Thrombolysis
Results show no intracranial hemorrhage and extended survival among patients at high risk of death
Bothell, WA, US, 30 March 2014 — EKOS Corporation, a BTG International group company, notes the presentation of the results of the SEATTLE II trial at ACC.14, the 63rd Annual Scientific Session and Exposition of the American College of Cardiology in Washington, DC in the United States. The results were presented by Dr. Gregory Piazza, MD, Staff Physician, Cardiovascular Division, Brigham and Women’s Hospital and Instructor of Medicine, Harvard Medical School.
The SEATTLE II study is a prospective, single-arm, multi-center trial to evaluate the safety and efficacy of ultrasound-facilitated catheter-directed low-dose thrombolysis, using the EKOS EkoSonic Endovascular System, for treating 150 patients with acute massive (N=31) or submassive (N=119) pulmonary embolism (PE). Chest computed tomography had to demonstrate proximal PE and a dilated right ventricle (RV/LV ratio ≥ 0.9) for patients to be eligible to participate. A dose of 24 mg tPA (thrombolytic) was used in the trial, administered either as 1 mg/hour for 24 hours with a unilateral catheter or 1 mg/hour/catheter for 12 hours with bilateral catheters. The mean RV/LV ratio in the study decreased from 1.55 pre-procedure to 1.13 at 48 hours post-procedure, a difference of 0.42 (p<0.0001).
Massive PE has a mortality rate of about 52% at 90 days.(1) In the SEATTLE II study, there were 31 patients presenting with massive PE manifested by syncope and hypotension. However, no patients with massive PE died within the 30 day follow up period. Of 150 patients in the overall study, only one death was directly attributed to PE.
There were no intracranial hemorrhages and no fatal bleeding events. Major bleeds occurred in 17 patients and was comprised of one severe bleed and 16 moderate bleeds. Six of the major bleeds occurred in patients with co-morbidities known to be associated with an increased risk of bleeding during thrombolytic therapy.
The abstract concluded that ultrasound-facilitated catheter-directed low-dose fibrinolysis for acute PE minimizes the risk of intracranial hemorrhage, improves RV function, and decreases pulmonary hypertension.
Samuel Z. Goldhaber, MD, Professor of Medicine, Harvard Medical School and Director, Thrombosis Research Group, Brigham and Woman’s Hospital (Boston, MA), and Principal Investigator for SEATTLE II said, “This trial represents a breakthrough in demonstrating the safety and efficacy of thrombolytic therapy for acute PE. The reduction of the RV/LV ratio by 0.42 is substantial and clinically significant, without any intracranial hemorrhage and using a much reduced lytic dose. These findings establish a new rationale for considering thrombolysis in both massive and submassive PE.”
Dr. Stavros Konstantinides, MD, Professor for Clinical Trials and Deputy Scientific Director, Center for Thrombosis and Hemostasis, Johannes Gutenberg University of Mainz, Germany, and principal investigator of PEITHO trial explains, “Aside from the massive PE patients who are in need of emergent therapy, the submassive PE patients while hemodynamically stable exhibit an elevated risk of clinical deterioration if managed conservatively, as observed in the PEITHO trial. The SEATTLE II study presents promising data in support of a catheter-based modality to provide rapid unloading of the right heart, thus reducing the risk of further deterioration.”
Matt Stupfel, General Manager at EKOS Corporation, added, “The recently published ULTIMA trial results demonstrated that EKOS treatment was clinically superior to anticoagulation with heparin alone in reversing right ventricular dilation at 24 hours, without an increase in bleeding complications. Together, the SEATTLE II and ULTIMA trial results provide compelling evidence that treatment with the EkoSonic Endovascular System improves the standard of care for patient with acute pulmonary embolism.”
1. Acute pulmonary embolism: clinical outcomes in the International Cooperative Pulmonary Embolism Registry (ICOPER), Goldhaber et al. Lancet. 1999 Apr 24;353(9162):1386-9.