Dr. Glenn Barnhart explains both valve replacements. There are tissue valves and mechanical valves. The good thing about tissue valves is that they do not require long-term anti-coagulation. The downside about tissue valves is that they can fail and will fail especially if implanted in a younger patient. Mechanical valves last forever. However, the patient has to be anti-coagulated for life. For more information about heart surgery at Swedish, please visit www.swedish.org/heartsurgery