"Using this tissue-engineered valve overcomes many of the problems with mechanical or donor valves because it is a living structure from the patient's own tissue, and so it does not cause an immunological reaction," said Pascal M. Dohmen, M.D., head of tissue engineering research and staff surgeon of the department of cardiovascular surgery at Charit Hospital in Berlin, Germany.
Dohmen and colleagues presented data on the first 23 patients to receive tissue-engineered pulmonary valves in the heart.
The patients, whose average age was 44, had aortic valve disease. The aortic valve connects the heart's left ventricle with the aorta, the main artery that distributes blood throughout the body. A diseased valve may either open or close improperly, and pressure can build in the ventricle, injuring the heart.
Doctors can treat the condition with drugs or by surgically replacing the patient's aortic valve with a donor valve, a mechanical valve or the patient's pulmonary valve. The pulmonary valve is between the right ventricle and the pulmonary artery. In a surgical "swap" called the Ross procedure, the abnormal aortic valve is replaced with the pulmonary valve, and the pulmonary valve is replaced with a donor valve.
Dohmen and colleagues engineered a new pulmonary valve from the patients' own cells. They implanted the patients' healthy pulmonary valve into the aortic position. Then they implanted the tissue-engineered valve in the right ventricular outflow tract, where the pulmonary valve originally was.
With up to three years of follow-up, the engineered valve's performance was "excellent," Dohmen reported. Echocardiography showed that the valves were functioning normally; the valve leaflets or flaps appeared smooth and
Contact: Carole Bullock
American Heart Association