Thirty-Seven Patients Treated With Ultrasound Accelerated Catheter Direct Pharmacological Thrombolysis

Main Category: Medical Devices / Diagnostics
Also Included In: Cardiovascular / Cardiology
Article Date: 24 Nov 2008 - 2:00 PDT

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At the 35th Annual VEITHsymposium (New York, NY), Karthikeshwar Kasirajan, MD, Assistant Professor of Surgery, Emory University School of Medicine, The Emory Clinic (Atlanta, Georgia) presented data on 37 patients treated with catheter-direct pharmacological thrombolysis using recombinant tissue plasminogen activator via the EKOS infusion system.

The study was conducted from December 2006 to August 2008. The purpose of the study was to evaluate the safety and efficacy of ultrasound as an adjunct to facilitate pharmacological thrombolysis. Dr. Kasirajan reported, "All patients received an initial bolus of 2mg of tPA. The mean age of patients was 52±19 years. Mean duration of arterial occlusion was 7.8±4.5-days and deep venous thrombosis (DVT) was 3.4±3 weeks. The mean occlusion length was 29±15-cms."

Complete thrombus resolution was noted in all arterial patients. Four patients with DVT had partial thrombus (40%) resolution; two patients had no change and all others had complete thrombus resolution. Of the 37 patients, 31 (83%) had a culprit lesion that was treated with a balloon angioplasty and stent placement. Mean duration of tPA infusion was 16.4±10-hours. A single patient had a neck hematoma secondary to an inadvertent central line placement and subsequently had early graft rethrombosis as she could not be anticoagulated. No other peri-operative complications were noted. At 6 month follow up one patient with DVT had an asymptomatic occlusion of her iliac stent.

Dr. Kasirajan concluded, "Use of ultrasound may help decrease the total dose of lytic agents used.

Larger prospective randomized studies are required to prove earlier recanalization compared to standard pharmacological thrombolysis." Robert W. Hubert, President/CEO of EKOS Corporation commented that, " Dr. Kasirajan's study is consistent with the recently published article by Dr. Sanjiv Parikh, et. al. in the April publication of JVIR which reported EKOS-treated patients received half the thrombolytic drug dose or were treated in half the time, or both, when compared to recent historical experience with standard non-ultrasound catheter directed thrombolysis (CDT). Additionally, the Kasirajan and Parikh studies were generated with our first generation product. Our newest product, the EkoSonic Mach 4, which was released to the market late July 2008 promises to perform even faster; up to 4x faster than standard CDT based on extensive in-vitro data of published this month by Dr. Soltani et. al. in Physics in Medicine and Biology. Using the Mach 4, we already have case reports of complete DVT resolution in less than 6 hours. The Mach 4, like our earlier generation product, often dissolves clot out to the vessel wall including clot formed behind the valves. Unlike mechanical devices, the EKOS products have a high percentage of complete thrombus resolution, do not create hemolysis and present a low risk of distal embolization. Clearly EKOS is setting a new standard of clot removal in the peripheral vasculature".

SIDEBAR

Venous thromboembolism and chronic venous insufficiency continue to be associated with high mortality and major morbidity in the United States. Each year over 700,000 patients in the US develop blood clots (thrombus) in the arteries (peripheral arterial occlusions or PAO) and veins (deep vein thrombosis or DVT) of their arms or legs. Often the clot resolves itself or can be treated with medication, e.g., blood thinners. However, because blood thinners prevent but do not actively remove clot, many DVT patients treated with blood thinners alone develop Post Thrombotic Syndrome (PTS). This condition is thought to result from damage to the delicate venous valves when exposed to the occluding blood clot for time periods greater than a few weeks. PTS can subsequently develop over months or years into a serious irreversible debilitating condition. Thus, many physicians are now performing interventional treatments such as the EKOS procedure to remove as much of the clot as possible immediately after diagnosis of significant DVT. The recently published American College of Chest Physicians (ACCP) guidelines include sections containing suggestions for antithrombotic/thrombolytic therapy for DVT. The new Guidelines align closely with the benefits of the EKOS MicroSonic™ Accelerated Thrombolysis (MSAT), and should allow physicians to confidently refer patients with acute DVT and PAO for treatment. Guidelines can be found at http://www.chestjournal.org/cgi/reprint/133/6_suppl/71S .

The ACCP Guidelines Advise

1.8 Treatment Strategies For Thrombus Removal for Acute DVT. Treatments that actively remove thrombus in patients with acute DVT have the potential to reduce acute symptoms and the risk for PTS. Thrombus removal directly reverses venous obstruction and can restore function in valves that were immobilized by thrombus. Indirectly, early removal of thrombus obstruction can prevent late development of venous valvular incompetence secondary to venous dilation in distal venous segments that were never involved with thrombosis. Randomized trials, patient registries and studies of other designs support that successful thrombus removal, using a variety of techniques can improve patient outcomes. It is also possible that thrombus removal and relief of venous obstruction may reduce the risk of recurrent VTE. Patients with iliofemoral DVT are the subset of patients with the largest thrombus burden and highest risk for post-thrombotic morbidity, with up to 75% having chronic painful edema and 40% having venous claudication when treated with anticoagulant therapy alone.

How This Relates to EKOS MSAT

MSAT is a minimally invasive endovascular treatment that offers fast, safe and complete dissolution of clots, allowing blood flow and valvular function to be restored. In clinical studies using MSAT as a standalone therapy, complete lysis was achieved in 70% of cases and partial lysis in 21%. In comparison, only 31% of cases in the National Venous Registry achieved complete lysis, even when post-adjunctive therapy was included. MSAT offers a safe treatment alternative that significantly reduces the risk of Post-Thrombotic Syndrome compared to anti-coagulation therapy.

The ACCP Guidelines Report

1.9.1 In selected patients with extensive acute proximal DVT (eg, iliofemoral DVT, symptoms for < 14 days, good functional status, life expectancy > 1 year) who have a low risk of bleeding, we suggest that CDT may be used to reduce acute symptoms and post-thrombotic morbidity if appropriate expertise and resources are available.

How This Relates to EKOS MSAT

MSAT is a sophisticated enhancement of catheter-directed thrombolysis (CDT) developed by EKOS Corporation that enables clots to be safely dissolved, more completely and in a fraction of the time required by traditional CDT. Less time to complete dissolution means a lower lytic drug dosage and that means an even lower risk of complications.

The ACCP Guidelines Report

1.9.3 We suggest pharmacomechanical thrombolysis (e.g. with inclusion of thrombus fragmentation and/or aspiration) in preference to CDT alone to shorten treatment time if appropriate expertise and resources are available.

How This Relates to EKOS MSAT

MSAT is a safer alternative to pharmacomechanical thrombolysis which shortens treatment time without the risks associated with thrombus fragmentation, and without damaging valves or the vascular wall. The EkoSonic system has the advantages of conventional CDT but 4 times faster without evidence of thrombus breakage or hemolysis. This translates into less time, less drug, less side effects.

About VEITHsymposium

Now in its fourth decade, VEITHsymposium™ provides vascular surgeons, interventional radiologists, interventional cardiologists and other vascular specialists with a unique and exciting format to learn the most current information about what is new and important in the treatment of vascular disease. The 5-day event features over 400 rapid-fire presentations from world-renowned vascular specialists with emphasis on the latest advances, changing concepts in diagnosis and management, pressing controversies and new techniques. Press registration details can be found at http://www.VEITHpress.org. VEITHsymposium is sponsored by Cleveland Clinic (Cleveland, OH).

About EKOS Corporation

EKOS Corporation pioneered the development and clinical application of microsonic technologies in medicine, introducing its first system for the treatment of vascular thrombosis in 2005. Today, interventional radiologists, cardiologists and vascular surgeons at leading institutions across the nation use EKOS MicroSonic™ Accelerated Thrombolysis (MSAT) to provide faster, safer and more complete dissolution of thrombus. In 2008, the company introduced the 2nd generation EkoSonic™ Endovascular System with Rapid Pulse™ Modulation. The EkoSonic System is FDA-cleared for controlled and selective infusion of physician-specified fluids, including thrombolytics, into the peripheral vasculature. It is currently used to treat patients with peripheral arterial occlusions (PAO) and deep vein thrombosis (DVT) and additional applications are being investigated.

EKOS Corporation