A mathematical model that explains the scientific basis of the Batista procedure -- a radical heart surgery -- has been developed by Charles R. Bridges, MD, ScD, a cardiothoracic surgeon at the University of Pennsylvania Medical Center.
This theory could help to better select appropriate candidates for the controversial procedure -- which involves the therapeutic removal of a large portion of heart muscle. It may also provide insights into the mechanics of heart failure in general, says Bridges. He will present his theory today at the American Heart Association's 24th Health and Science Journalists' Forum, in Portland, Oregon.
The Batista procedure was developed in the early 1980s by Randas J.V. Batista, a Brazilian surgeon, for patients with enlarged hearts due to severe cardiac disease. Batista has completed over 500 of these surgeries.
Also called cardioreduction or partial left ventriculectomy, the operation is based on the idea that if part of the enlarged heart-muscle wall is removed, the ratio of heart diameter to mass could be returned to a near-normal level. In patients with severe heart failure the overall mass of the heart is markedly increased, with a disproportionate enlargement of its diameter and thickening of the heart wall.
Batista reasoned that because the normal heart diameter-to-mass ratio is constant across vastly different-sized species--from snakes to humans to buffalo--perhaps removing part of an enlarged heart could improve cardiac function.
"Although this hypothesis sounds plausible, the concept of removing heart muscle from an already diseased heart with marginal function is nothing short of revolutionary," says Bridges, who is an assistant professor of surgery at Penn and also holds a doctorate in engineering.
"But plausibility alone is not an adequate theory. My model will allow us to predict exactly how dilated the heart muscles must be, and how much muscle needs to be removed for the procedure to be helpful to the patient."
But in what cases is less heart actually more beneficial? Bridges's model predicts that the cardiac output of patients whose ventricles are sufficiently enlarged can be significantly increased with removal of as much as 50 percent of the hearts' mass. German colleagues of Bridges recently confirmed that the model correctly predicted a substantial decrease in heart-wall stress in five Brazilian patients.
The Batista procedure has shown promising early results for patients who have few surgical alternatives, specifically situations where transplantation is not an option or where heart donors are limited.
"The model may accelerate the development of a rational strategy for patient selection for this procedure and may lead to improved results," remarks Bridges.
Editor's Note: Until Wednesday morning, Dr. Bridges may be reached directly at (503) 226-7600. After that, he may be reached at his Penn office: (215) 349-8285.