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Arterial switch operation has lasting effects on artery function

NEW YORK (Reuters Health) – Children who have had open heart surgery to switch their great arteries have significantly altered function of these arteries later in life, according to a new study from Hong Kong.

The arterial switch operation is done to correct a congenital defect known as complete transposition of the great arteries, in which the aorta and the pulmonary artery are transposed at birth.

More than a decade after the procedure, these patients had significantly different levels of arterial strain and stiffness, the study found, which may affect heart function.

Senior author Dr. Yiu-fai Cheung, a pediatric cardiologist at the University of Hong Kong, said the results suggest that these patients may require exercise restrictions or medical treatment.

The study compared 30 patients age 12 to 21 who had had an arterial switch operation at birth with 22 controls matched by body characteristics like weight and height.

All of the arterial switch patients had had their operation at least 10 years prior, a median of 14 days after birth, the researchers report in the American Journal of Cardiology, online November 27.

Both at rest and during exercise, the arterial switch patients had significantly lower aortic strain and distensibility, greater aortic and carotid stiffness, and higher systolic blood pressure than control subjects.

And 76.7% of the arterial switch patients had a dilated aortic sinus, while 20% had significant aortic regurgitation.

The arterial switch operation was first done in the 1970s and has since become the surgery of choice for complete transposition of the great arteries, the authors note. As patients get older, problems with the transposed aorta, including dilation of the neo-aortic root and incompetence of the neo-aortic valve, are becoming concerns.

Dr. Cheung said that there is no standard approach to managing these problems, but that his findings suggest that either medical or physical interventions may be warranted.

“Management of congenital heart disease-related aortopathy with aortic root dilation has remained controversial,” Dr. Cheung told Reuters Health by email. “Our findings provide a basis for consideration of drugs such as angiotensin-converting enzyme inhibitors, which has been shown to reduce arterial stiffness and arterial afterload, and hence may slow the progress of neoaortic dilation and regurgitation.”

Exercise restriction is not required for these patients according to current guidelines, but Dr. Cheung said this may need to be reexamined “in light of the persistently altered arterial mechanics during exercise” found in the study, he added.

SOURCE: http://bit.ly/1bCmDjv

Am J Cardiol 2013.