Asian Cardiovasc Thorac Ann 2006;14:e55-e57
© 2006 Asia Publishing EXchange Ltd
Intraoperative Aortic Dissection in Pediatric Heart Surgery
Narutoshi Hibino, MD,
Yorikazu Harada, MD,
Takeshi Hiramatsu, MD,
Satoshi Yasukochi, MD,
Gengi Satomi, MD
Department of Cardiovascular Surgery, Nagano Children’s Hospital, Nagano, Japan
For reprint information contact: Narutoshi Hibino, MD Tel: 81 26 373 6700 Fax: 81 26 373 5432 Email: nhhibino{at}uranus.dti.ne.jp, Department of Cardiovascular Surgery, Nagano Children’s Hospital, 3100 Toyoshina, Toyoshina-cho, Minamiazumi-gun, Nagano, Japan.
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ABSTRACT
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Intraoperative aortic dissection occurred in a 3-year-old-boy undergoing repair of an atrial septal defect. Transesophageal echocardiography was useful for the diagnosis, and conservative medical treatment under close observation was feasible in this case which involved a limited intimal tear.
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INTRODUCTION
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A 3-year-old-boy was referred to our hospital for repair of an atrial septal defect. On admission, a systolic ejection murmur and fixed splitting of the second sound were identified on cardiac auscultation. Preoperative chest radiography indicated cardiomegaly, and electrocardiography showed incomplete right bundle branch block. Echocardiography revealed an ostium secundum defect. An operation for closure of the atrial septal defect was undertaken. Under general anesthesia, a full median sternotomy was carried out. Pursestring sutures were placed on both venae cavae and the ascending aorta for cannulation. Aortic cannulation was performed after making a small incision in the ascending aorta with confirmation of bleeding from the aorta. The cannula was connected to the cardiopulmonary bypass (CPB) circuit, backflow into the tube from the ascending aorta was checked, and CPB was started with ascending aortic perfusion and bicaval drainage. Nine minutes later, CPB was established with total flow. However, the pressure in the circuit increased suddenly and left radial arterial pressure dropped with bradycardia. After stopping CPB, the aortic cannula was removed immediately and placed in the left femoral artery. The CPB was started again with stable perfusion. Transesophageal echocardiography showed an intimal flap in the ascending aorta that reached to the base of ascending aorta. As coronary flow was detected from the true lumen of the dissected aorta, conservative medical treatment for the aortic dissection was decided, and direct closure of the atrial septal defect was performed under mechanical ventricular fibrillation. Weaning from CPB was uneventful.
After the operation, meticulous control of blood pressure was continued with medication. Computed tomography showed dissection of the ascending aorta from the level of the bifurcation of the pulmonary artery to the proximal aortic arch (Figure 1
). Ten days after the operation, echocardiography detected a thrombus in the false lumen at the base of the ascending aorta. Although follow-up computed tomography showed a false lumen with a small amount of blood flow, the diameter of the aorta and the false lumen were unchanged. Therefore, the boy was discharged 1 month after the operation and underwent follow-up at our outpatient clinic.
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Figure 1. Computed tomography 10 days postoperatively showing dissection of the ascending aorta from the level of the bifurcation of the pulmonary artery to the proximal aortic arch.
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DISCUSSION
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Intraoperative aortic dissection is a rare but catastrophic complication of cardiac surgery. Iatrogenic aortic dissection occurs in 0.16% to 0.35% of adult cardiac surgery cases.1,2 The operative mortality for patients with intraoperative ascending aortic dissection is 20% 33%.1,2 There are no other reports of intraoperative aortic dissection in pediatric cardiac surgery as far as we know. Atherosclerosis and congenital connective tissue disorders are known to be predisposing factors for the development of aortic dissection.1 However, nearly half of the aortic dissections in one study occurred in patients with clinically normal aortas.2 This suggests that pediatric patients without connective tissue disorders might possibly suffer aortic dissection in spite of normal aortas.
Preventative measures including control of systolic blood pressure during cannulation, careful placement of the aortic cannula, deep pursestring sutures for cannulation, and careful control of the aortic clamp are generally important and may reduce the incidence of injury to the aorta. Once aortic dissection is suspected, prompt use of transesophageal echocardiography to confirm the diagnosis, and rapid and appropriate management are necessary to achieve a good outcome. Transesophageal echocardiography has been found to be very helpful in diagnosing and deciding the management in suspected acute dissection of the aorta during CPB.3,4 Mortality rate increases with a delay in diagnosis. Still and colleagues1 reported mortality rates of 20% for detections discovered intraoperatively, and 50% for those discovered postoperatively.
Conservative medical treatment is a possible choice of treatment if the intimal tear is extremely localized. In congenital heart disease, surgical repair is sometimes difficult due to the size of the aorta. In addition, as the aortic tissue of young children is soft and pliable, dilation of a false lumen might develop less extensively compared to adults. In this patient, the diameter of the aorta and false lumen remained unchanged 3 months after the operation (Figure 2).
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Figure 2. Computed tomography 3 months after the operation; although there was a false lumen with some blood flow, the diameter of the aorta and the false lumen were unchanged.
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There are two types of repair: primary repair and graft replacement. The extent and location of the intimal tear determine the type of repair. Primary repair with the shortest possible CPB time is the procedure of choice in patients with localized intimal disruption. Interposition of a graft may be necessary for more extensive lesions. We suggest that conservative medical treatment under close observation may be the optimal procedure in the case of intraoperative aortic dissection due to a limited tear in children.
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REFERENCES
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- Still RJ, Hilgenberg AD, Akins CW, Daggett WM, Buckley MJ. Intraoperative aortic dissection. Ann Thorac Surg 1992;53:374–80.[Abstract/Free Full Text]
- Murphy DA, Craver JM, Jones EL, Bone DK, Guyton RA, Hatcher CR Jr. Recognition and management of ascending aortic dissection complicating cardiac surgical operations. J Thorac Cardiovasc Surg 1983;85:247–56.[Abstract]
- Varghese D, Riedel BJ, Fletcher SN, Al-Momatten MI, Khaghani A. Successful repair of intraoperative aortic dissection detected by transesophageal echocardiography. Ann Thorac Surg 2002;73:953–5.[Abstract/Free Full Text]
- Shen CH, Wu CC, Hung CM, Ho WM. Intraoperative aortic dissection—a case report. Acta Anaesthesiol Sin 2002;40:85–9.[Medline]
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ABSTRACT
INTRODUCTION
