SEATTLE II Supports Treatment of Acute PE With the Ekos EkoSonic System

March 30, 2014—Ekos Corporation (Bothell, WA), a BTG International group company, announced that the results of the SEATTLE II trial were presented at ACC.14: the 63^rd annual scientific session of the American College of Cardiology in Washington, DC. Gregory Piazza, MD, who is a staff physician in the Cardiovascular Division of Brigham and Women’s Hospital and Instructor of Medicine at Harvard Medical School in Boston, Massachusetts, presented the data.

According to Ekos, the multicenter SEATTLE II trial is a prospective, single-arm evaluation of the safety and efficacy of ultrasound-facilitated, catheter-directed, low-dose thrombolysis using the company’s EkoSonic endovascular system for treating 150 patients with acute massive (n = 31) or submassive (n = 119) pulmonary embolism (PE). Chest CT had to demonstrate proximal PE and a dilated right ventricle (RV/LV ratio ≥ 0.9) for patients to be eligible for the trial.

A dose of 24-mg tissue plasminogen activator was used in the trial, administered either as 1 mg per hour for 24 hours with a unilateral catheter or 1 mg per hour per catheter for 12 hours with bilateral catheters. The mean RV/LV ratio in the study decreased from 1.55 preprocedure to 1.13 at 48 hours postprocedure, a difference of 0.42 (P < .0001), reported Ekos.

In the SEATTLE II study, there were 31 patients presenting with massive PE manifested by syncope and hypotension. The company noted that massive PE has a mortality rate of approximately 52% at 90 days. However, no patients with massive PE died within the 30-day follow-up period. Of 150 patients in the overall study, there was one death directly attributed to PE. 

Additionally, there were no intracranial hemorrhages and no fatal bleeding events. Major bleeds occurred in 17 patients, which included one severe bleed and 16 moderate bleeds. Six of the major bleeds occurred in patients with comorbidities known to be associated with an increased risk of bleeding during thrombolytic therapy.

The SEATTLE II investigators concluded that ultrasound-facilitated, catheter-directed, low-dose fibrinolysis with the EkoSonic system for acute PE minimizes the risk of intracranial hemorrhage, improves RV function, and decreases pulmonary hypertension. 

Samuel Z. Goldhaber, MD, serves as Principal Investigator for the SEATTLE II trial. Dr. Goldhaber is Professor of Medicine at Harvard Medical School and Director of the Thrombosis Research Group at Brigham and Woman’s Hospital in Boston.

In the Ekos press release, Dr. Goldhaber commented, “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.”  

Stavros Konstantinides, MD, Principal Investigator of the PEITHO (Pulmonary Embolism Thrombolysis Study) trial, added, “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.” Dr. Konstantinides is Professor for Clinical Trials and Deputy Scientific Director of the Center for Thrombosis and Hemostasis at Johannes Gutenberg University in Mainz, Germany.

In January, Ekos announced that results of the ULTIMA (Ultrasound-Accelerated Thrombolysis of Pulmonary Embolism) trial were published by Nils Kilcher, MD, et al in Circulation (2014;129:479–486). The ULTIMA results demonstrated that treatment with the EkoSonic system was clinically superior to anticoagulation with heparin alone in reversing RV dilation at 24 hours, without an increase in bleeding complications.

The SEATTLE II and ULTIMA trial results provide compelling evidence that treatment with the Ekos EkoSonic endovascular system improves the standard of care for patient with acute pulmonary embolism, stated the company.