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Clinical Trial Demonstrates Positive Results for St. Jude Medical Device Treating Coronary Bypass Graft Blockages

Posted on: Tuesday, 18 October 2005, 12:00 CDT

Data from a key clinical trial show that a new embolic protection device from St. Jude Medical, Inc. (NYSE:STJ) has demonstrated positive results for treating patients with saphenous vein coronary bypass grafts. The trial results were presented today during a Late Breaking Clinical session at the Cardiovascular Research Foundation's Seventeenth Annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium in Washington, D.C.

The Proxis(TM) Embolic Protection System, currently under review by the U.S. Food and Drug Administration (FDA) as an embolic protection system, would give cardiologists an alternative means of treating approximately 87,000 patients annually in the U.S. (160,000 worldwide), including 29,000 in the U.S. (54,000 worldwide), who currently have no treatment options because their blockages, called lesions, are located too far distally, or "downstream" in the vessel.

Currently, Proxis is available in Europe for embolic protection during PCI for saphenous vein grafts. In the U.S., Proxis is cleared for Flow Control use, where a cardiologist can temporarily stop blood flow to a vessel and inject or aspirate fluid as needed.

Patients with saphenous vein coronary bypass grafts have undergone bypass surgery during which the saphenous vein from the leg was sutured to the aorta and the coronary artery to create a new passage for blood flow. If the saphenous vein graft (SVG) develops a lesion, a percutaneous coronary intervention (PCI) procedure is often performed (such as delivering a stent to open a blocked or clogged artery) to open the blocked SVG. Embolic protection systems are used to catch debris that can be dislodged during a PCI. If debris escapes and flows downstream, it increases the risk of heart attack even if the coronary intervention is successful. Due to this fact, PCIs involving patients with saphenous vein grafts have been associated with significant complication rates.

The Proxis Embolic Protection System places a sealing balloon proximally, or upstream, to the lesion. The inflated balloon temporarily suspends blood flow so a guidewire can cross the lesion without sending debris into the bloodstream. An interventional device (such as a stent) is then delivered and the embolic debris is removed (aspirated) from the vessel. Once the intervention is complete, the balloon is deflated, blood flow is restored and Proxis is removed.

While several distal embolic protection devices are available (where the protection is placed distal, or "downstream" to the lesion), Proxis is the first-of-its-kind designed to treat a majority of the nearly 148,000 saphenous vein graft interventions in the U.S. each year (270,000 worldwide), including the nearly 20 percent of cases where current distal embolic protection devices cannot be used.

"Many vein graft lesions have challenged interventional cardiologists because their location has made it difficult, if not impossible, to position current embolic protection devices so as to protect the downstream bed," said Campbell Rogers, M.D., Brigham and Women's Hospital, Boston, Mass., and Principal Investigator of the PROXIMAL Embolic Protection Trial who presented the study results at TCT. "The Proxis device not only allows protection for most vein graft lesions (and our results suggest it may offer better protection from post-procedural complications than current devices), but it also can be deployed 'upstream' of lesions not suitable to protection with current distal protection devices."

The PROMIXAL trial assessed whether Proxis was substantially equivalent to previously-cleared devices as determined by the rate of major adverse cardiac events (MACE) at 30 days, the primary endpoint of the trial. Proxis proved equivalent to previously-cleared devices. In the as-treated population, meaning that patients were grouped depending on what type of embolic protection device they received, the MACE rate of the 241 patients treated with Proxis was 7.1 percent, compared to an 11.7 percent MACE rate in the 282 patients treated with the distal protection devices. In that same population, the study demonstrated that patients treated with Proxis were 60 percent less likely to experience a MACE than those treated with a distal embolic protection device. Moreover, when comparing device to device in the middle section of the vessel, where either a proximal or distal system could be used, the MACE rate for Proxis was 6.2 percent compared to 11.2 percent for the distal devices.

The trial began in June 2003 and involved 600 patients in a prospective, randomized, two-arm trial at 67 research sites nationwide. Patients scheduled to undergo a PCI on a saphenous vein graft lesion were randomized to a test arm or to a control arm. The MACE rate was defined as the composite of death, Q-wave or non-Q-wave myocardial infarction, emergent coronary artery bypass surgery (CABG), or target vessel revascularization (TVR).

"The PROXIMAL trial has shown that Proxis is as effective as systems already cleared by the FDA, offering promise to tens of thousands of patients whose medical needs have previously gone unmet," said Paul R. Buckman, president of St. Jude Medical's Cardiology Division. "Proxis gives clinicians an additional tool for protecting these patients when it's not suitable to deploy a device below the lesion."

St. Jude Medical, Inc. (www.sjm.com) is dedicated to the design, manufacture and distribution of innovative medical devices of the highest quality, offering physicians, patients and payers outstanding clinical performance and demonstrated economic value.

Any statements made regarding St. Jude Medical's anticipated future product launches, regulatory approvals, revenues, earnings, market shares, and potential clinical success are forward-looking statements which are subject to risks and uncertainties, such as those described in the Company's 8-K filed October 17, 2005. Actual results may differ materially from anticipated results.

Source: Business Wire

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