Managed Care - January 2008 - (Page 54) TOMORROW’S MEDICINE Linx Technology Avoids Heart Valve Complication Heart valves made from new composite materials minimize calcification, a common problem that can lead to a second valve replacement Thomas Morrow, MD ne of the hardest working muscles in the body is heart muscle: In a normal lifetime, the human heart beats about 3.5 billion times, give or take a few million. So it shouldn’t be a surprise that some parts of the heart wear out, and in particular, the heart valves take a pounding — from disease, structural defects, calcification, and normal wear and tear. Each year, about 300,000 people need new valves. Valvular heart disease can be divided into two main types: stenosis, which means the outflow track diameter is smaller and makes the pumping of blood more difficult for the heart, and regurgitation, which is when the valve does not close tightly and allows for the backflow of blood during diastole. Many people with valvular disease require surgery, either to repair or to replace the diseased valve once stenosis or regurgitation begins to be a threat to life. The ultimate treatment is a heart valve replacement, first performed in 1952. O tor is that they tend to wear out and need to be replaced about every 10 years. In 1998 the American Heart Association issued guidelines that recommended that most patients age 65 and older be given a bioprosthetic valve because the risk that clotting carries (strokes and pulmonary emboli) is greater than the risk from having a second valve replacement. Despite this recommendation, a study using Medicare data found that overall, only about 50 percent of patients undergoing a heart valve replacement received a bioprosthetic valve. Further analysis showed that the top high volume valve replacement facilities were 2.3 times as likely to implant a bioprosthetic valve than were the lowest volume hospitals. Calcification Calcification is a risk associated with bioprosthetic valves, but advances in medical technology are leading to improvements. In early December 2007, the United States Food and Drug Administration approved the sale of a new heart valve that fights calcification. The St. Jude Medical Epic heart valve combines an anticalcification technology with a valve design that has been around for more than 15 years. The Epic boasts a triple composite construction devoid of the septal muscle bar. Lacking the septum allows this heart valve to maximize blood flow and removes a potential calcification site. It also has a low-profile design that facilitates implantation and enhances blood flow in both aortic and mitral positions. Replacement valves There are two broad categories of replacement heart valves: mechanical and bioprosthetic. Mechanical valves, also called artificial valves, are made of metal and other materials. They are also subject to clotting complications that require long-term anticoagulation treatment. Bioprosthetic valves also come in two types: human valves and modified valves from animal donors. These valves are less likely to cause blood clotting than are mechanical replacements, and also are designed to function like natural heart valves. Their greatest limiting facThomas Morrow, MD, is the immediate past president of the National Association of Managed Care Physicians. He has 23 years of managed care experience at the payer or health plan level. Linx technology First of all, glutaraldehyde treatment fixes the bioprosthetic valve by performing three tasks: It sterilizes the valve tissue, renders the tis- 54 MANAGED CARE / JANUARY 2008
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