Focus Issue on Bifurcation Intervention
Peripheral
A Prospective, Single-Arm, Multicenter Trial of Ultrasound-Facilitated, Catheter-Directed, Low-Dose Fibrinolysis for Acute Massive and Submassive Pulmonary Embolism: The SEATTLE II Study

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Abstract

Objectives

This study conducted a prospective, single-arm, multicenter trial to evaluate the safety and efficacy of ultrasound-facilitated, catheter-directed, low-dose fibrinolysis, using the EkoSonic Endovascular System (EKOS, Bothell, Washington).

Background

Systemic fibrinolysis for acute pulmonary embolism (PE) reduces cardiovascular collapse but causes hemorrhagic stroke at a rate exceeding 2%.

Methods

Eligible patients had a proximal PE and a right ventricular (RV)-to-left ventricular (LV) diameter ratio ≥0.9 on chest computed tomography (CT). We included 150 patients with acute massive (n = 31) or submassive (n = 119) PE. We used 24 mg of tissue-plasminogen activator (t-PA) administered either as 1 mg/h for 24 h with a unilateral catheter or 1 mg/h/catheter for 12 h with bilateral catheters. The primary safety outcome was major bleeding within 72 h of procedure initiation. The primary efficacy outcome was the change in the chest CT–measured RV/LV diameter ratio within 48 h of procedure initiation.

Results

Mean RV/LV diameter ratio decreased from baseline to 48 h post-procedure (1.55 vs. 1.13; mean difference, −0.42; p < 0.0001). Mean pulmonary artery systolic pressure (51.4 mm Hg vs. 36.9 mm Hg; p < 0.0001) and modified Miller Index score (22.5 vs. 15.8; p < 0.0001) also decreased post-procedure. One GUSTO (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries)–defined severe bleed (groin hematoma with transient hypotension) and 16 GUSTO-defined moderate bleeding events occurred in 15 patients (10%). No patient experienced intracranial hemorrhage.

Conclusions

Ultrasound-facilitated, catheter-directed, low-dose fibrinolysis decreased RV dilation, reduced pulmonary hypertension, decreased anatomic thrombus burden, and minimized intracranial hemorrhage in patients with acute massive and submassive PE. (A Prospective, Single-arm, Multi-center Trial of EkoSonic® Endovascular System and Activase for Treatment of Acute Pulmonary Embolism (PE) [SEATTLE II]; NCT01513759)

Key Words

catheter embolectomy
catheter thrombolysis
fibrinolysis
pulmonary embolism
right ventricular failure
thrombolysis

Abbreviations and Acronyms

CT
computed tomography
DVT
deep vein thrombosis
PE
pulmonary embolism
RV
right ventricular
RV/LV
right ventricular-to-left ventricular
t-PA
tissue-plasminogen activator

Cited by (0)

This study was funded by a research grant from EKOS, a BTG International group company. Dr. Piazza receives research support from EKOS, Bristol-Myers Squibb, Daiichi-Sankyo, and Janssen. Dr. Jaff is a noncompensated member of the Data Safety and Monitoring Board of EKOS and a Board member of VIVA Physicians, a 501(c)(3) not-for-profit education and research organization. Dr. Ouriel holds equity in and is an employee of Syntactx, which receives fees for core laboratory activities from EKOS. Dr. Jones receives honoraria for serving on the Speaker Bureau of Medtronic and EKOS; and receives consulting fees from Cordis. Drs. Engelhardt, Sterling, Gurley, Bhatheja, Kennedy, Goswami, Natarajan, Rundback, Sadiq, S.K. Liu, Bhalla, Raja, Weinstock, Cynamon, Elmasri, Garcia, Kumar, Ayerdi, Soukas, Kuo, and Goldhaber has received research support from EKOS, a BTG International Group company. Dr. P.-Y. Liu receives consulting fees from EKOS. Dr. Bhatheja is a speaker for St. Jude Medical and Cardiovascular Systems Inc. Dr. Goswami is a consultant for Boston Scientific. Dr. Gurley is a speaker for EKOS. Dr. Weinstock is a consultant for W.L. Gore. Dr. Hohfelder has reported that he has no relationships relevant to the contents of this paper to disclose.

The results of this prospective, single-arm, multicenter trial were presented in abstract form on March 30, 2014 at the American College of Cardiology Annual Scientific Sessions in Washington, DC.