UPMC Physicians Studying New Blood Filtering Device Used During Angioplasty
PITTSBURGH, January 7, 2002 — Physicians at the University of Pittsburgh Medical Center Cardiovascular Institute are beginning a research study to test the effectiveness of a small basket-like filtering device to capture particles in the blood that may be released during angioplasty.
The device allows blood to flow through it while at the same time capturing any particles that may become loose during balloon angioplasty and stent placement. The filter is removed once the procedure is completed. The effectiveness of the filter will be tested against another currently used device, which uses a balloon to stop debris movement. In this device, blood flow is stopped.
The device is for use in patients who have had prior heart bypass surgery and whose bypass grafts have subsequently narrowed. Many of these patients had bypass surgery ten years ago or longer. Over time, arterial pressures degrade the vein grafts, which then fill up and become clogged with a cheese-like plaque.
"One of the potential risks of reopening narrowed bypass grafts is that some of the material causing the narrowing may come loose and be carried downstream plugging up the small blood vessels resulting in significant heart damage" said Peter J. Counihan, M.D., interventional cardiologist, assistant professor of medicine at the University of Pittsburgh School of Medicine and principal investigator in the study. "This debris causes a heart attack in up to 25 percent of patients undergoing angioplasty following bypass surgery."
An earlier study found that eight percent of patients undergoing angioplasty with balloon protection had a cardiac event (death, heart attack, stent closure), while those without balloon protection had an event rate of 15 percent.
During the procedure, a catheter is used to thread the basket filter through an artery and position it in the vein graft just beyond the blockage. The basket filter collapses within the catheter for positioning and then resumes its basket-like shape when placed in the vein graft. The interventional cardiologist then opens the narrowing with a balloon angioplasty and places a stent in the narrowing to keep it open. The basket and contents are removed by collapsing the basket and contents into a retrieval catheter. Following the procedure a pathologist analyzes the atherosclerotic plaque debris from the basket.
The multi-center study will enroll 800 patients nationwide with about 50 patients participating in the study at UPMC Presbyterian. The study is randomized so that half of the patients will be treated with the basket filter device and half will be treated with the balloon filter device.
The CAPTIVE study (CardioShield Application Protects during Transluminal Intervention of Vein Grafts by reducing Emboli) is sponsored by MedNova, the manufacturer of the device, which is called the CardioShield™ Bare Wire Myocardial Protection system.