. (1977). Thorax, 32,[743][744][745][746][747][748] Delayed non-mycotic false aneurysm of ascending aortic cannulation site. Two cases of delayed non-mycotic false aneurysm arising from the ascending aortic cannulation site, presenting one-and-a-half years and seven years after cardiopulmonary bypass, are described. These two cases represent an incidence of 0O12% of this complication. Repair using profound hypothermia and circulatory arrest with femoral artery and femoral vein cannulation for cardiopulmonary bypass is recommended. The advantages and complications of aortic cannulation are discussed and recommendations to minimise the complications of cannulation are made. The clinical presentation and diagnosis of non-mycotic false aneurysms arising from the aortic cannulation site are described. In addition one delayed and two early cases of non-mycotic cannulation site false aneurysms previously published are analysed. Surgeons should be alert to the possibility of this complication in all patients who have had aortic cannulation for cardiopulmonary bypass even in ithe distant past. Unexpected symptoms such as constant anterior chest pain, dysphagia, hoarseness, and increasing widening of the superior mediastinum on the chest radiograph warrant prompt investigation.Delayed non-mycotic false aneurysm arising from the ascending aortic cannulation site is a rare complication of this technique for arterial return in cardiopulmonary bypass, and only one case has been reported previously (Williams et al., 1976 Table). Cannulation and decannulation were carried out uneventfully and the sternotomy wound healed satisfactorily. The postoperative progress was uncomplicated and he was discharged from hospital two weeks after the operation. He was seen regularly in the outpatient department and within six months he was working a 12-hour day on his farm. However, he remained in atrial fibrillation and 10 months later he underwent an unsuccessful attempt at DC cardioversion. During this procedure a small burn was produced over one of the sternal suture wires at the level of the manubriosternal junction, possibly due to inappropriate contact with the electrode. This ultimately resulted in a sinus in which the sternal wire could be easily palpated. This sinus was excised and the sternal wire removed. Histological examination showed a foreign-body reaction with chronic inflammatory cells but culture from the area was sterile.The patient was readmitted to hospital in February 1971 with a fluctuant swelling in the upper third of the sternotomy scar at the site of the previous sinus. This produced serosanguinous fluid when incised, but no organisms were cultured from the fluid. As he had a low-grade pyrexia, 743 on 3 April 2019 by guest. Protected by copyright.