[Intraoperative aortic injury caused by arterial perfusion cannula during extended aortoplasty in a patient with Williams syndrome].

An 8-year-old girl with Williams syndrome underwent repair of supravalvular aortic stenosis by extended aortoplasty (Doty technique). Although she was weaned from bypass successfully, direct epiaortic ultrasound scanning disclosed the acute luminal narrowing of the ascending aorta at the level of aortic cannulation. The perfusion was restarted through the tube graft anastomosed to the left carotid artery and the ascending aorta was cross-clamped. The longitudinal incision at the site of prior aortic cannulation disclosed the intramural hematoma at the posterior wall of the ascending aorta. The stenosis was repaired with the patch enlargement of the anterior wall. As the dysplastic wall of the ascending aorta in patients with this syndrome may be injured by arterial cannula, an appropriate positioning of the cannula is mandatory to lessen the risk of intimal injury.