71.   We can replace heart valves that are worn out.

72.   Wallace needed the second operation last Friday to bypass clogged coronary arteries and fix two leaking heart valves.

73.   A heart valve regulates the flow of blood from the heart.

74.   After successful surgery to repair the damaged heart valve, the Inter Milan star has returned to competitive action this season but so far played few matches.

75.   Another study by Dr. George W. Petty of the Mayo Clinic shows the importance of leaky and deformed heart valves in triggering strokes.

76.   Another risk is that laser could accidentally fire into the heart valves.

77.   Another study by Dr. George Petty of the Mayo Clinic shows the importance of leaky and deformed heart valves in triggering strokes.

78.   Bioengineering involves the development of new materials to help solve medical problems, such as artificial heart valves, new materials for replacement hip joints and artificial skin.

79.   Cleveland Clinic surgeon Dr. Bruce Lytle repaired the heart valve in a four-hour surgery on Monday.

80.   During the surgery doctors determined that repair to the damaged heart valve was too difficult and decided to repair the leaking valve with pig tissue.