Unusual complication of the Hancock porcine heterograft: strut compression in the aortic root

A 65-year-old man underwent aortic valve replacement and triple coronary artery bypass grafting which were followed by gradual late postoperative thrombosis of his 25 mm. Hancock porcine aortic heterograft. At reoperation, the valve struts were noted to be angled centrally into the aortic lumen and dense thrombus completely filled all three sinuses. After valve removal and extensive debridement of the aortic anulus, including relaxing incisions, a diameter of only 23 mm. was obtained. A 23 mm. Björk-Shiley aortic prosthesis was inserted and the patient's recovery was uneventful. This previously unreported complication resulted from the insertion of a too-large Hancock porcine heterograft into a relatively small aortic root, resulting in circumferential strut compression, impedance of central flow, and subsequent valve thrombosis.