Study Examines Ultrasound Accelerated Thrombolysis in Acute PE


January 20, 2012
The Ekos drug delivery catheters deliver the lytic drug, while the non-cavitational ultrasound energy gently perfuses the drug deep into the clot, limiting the amount that escapes downstream.

January 20, 2012 - Robert J. Kennedy, M.D., interventional radiologist at Holmes Regional Medical Center in Melbourne, Fla., this week presented data on thrombus resolution and hemodynamic recovery using ultrasound accelerated thrombolysis in acute pulmonary embolism (PE) at the International Symposium on Endovascular Therapy (ISET).

“New treatment guidelines increasingly favor catheter-directed techniques for the treatment of acute PE targeting high-risk patients whose hemodynamic status is unstable, as well as intermediate-risk patients whose conditions may be stable but exhibit poor outcomes if large thrombus burdens remain,” Kennedy said. His study evaluates the safety and effectiveness of ultrasound accelerated thrombolysis when prompt treatment is warranted to rapidly resolve the thrombus and improve cardiopulmonary function.

“We retrospectively reviewed our experience in treating consecutive acute PE patients between 2009 and 2011,” Kennedy said. “Upon diagnosis of PE by pulmonary CTA or V/Q scan, all patients received anticoagulant therapy and treatment using the Ekosonic Endovascular system which was placed into the thrombus to facilitate ultrasound-accelerated thrombolytic infusion at 0.5 or 1 mg/hour/catheter.”

Kennedy reported that patient outcomes, including clinical improvement, pulmonary artery pressure, thrombus removal (Miller score) and complications, were documented to evaluate treatment success following overnight thrombolytic infusion. 

He reported that treatment of 40 patients (25 men, 15 women; aged 60±17; 35 bilateral PE) resulted in complete thrombus clearance (90 percent) in 25 and near-complete (50-90 percent) clearance in the remaining 15 patients following infusion of 34±12 mg tPA over 20.3±7.2 hours.  Mean pulmonary artery pressure decreased significantly from pre- to post-treatment (47±16 to 38±13, p<.001), as did the Miller score (25±3 to 17±5, p<.001). Clinical improvement of symptoms was observed in all 40 patients post-treatment, with no major hemorrhagic complications. All patients survived to hospital discharge with a median length of one-day ICU stay and nine days hospital stay.  

The current study demonstrates safety and effectiveness of ultrasound accelerated thrombolysis in treating a population of patients with severe thrombus burden and increased risk for poor outcomes when untreated or undertreated. Treatment success was predictable, with angiographic evidence of thrombus clearance corroborated by significant reduction of pulmonary artery pressure and Miller score using a low dose thrombolytic infusion protocol.

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