Surgical strategy to prevent cardiac injury during reoperation in infants
© Knott-Craig et al; licensee BioMed Central Ltd. 2008
Received: 24 September 2007
Accepted: 28 February 2008
Published: 28 February 2008
Simplified Aortic Cannulation (SAC), wherein the innominate artery is used as the arterial inflow site rather than the ascending aorta, has proved to be a useful technique for arterial cannulation especially for small neonates undergoing complex cardiac operations. Since few technical options are available for re-entry cardiac injuries in small infants, we postulate that this technique may be equally helpful in those situations.
We employed SAC in 4 infants undergoing reoperative cardiac surgery (prior Norwood, n = 2; prior arterial switch operation with suprasystemic pulmonary artery pressures after a Le Compte maneuver, n = 1; prior Ebstein's anomaly, n = 1). In all cases the innominate artery was exposed at the level of the supra-sternal notch, and a 3.5 mm expanded polytetrafluoroethylene (ePTFE) graft was anastomosed to the innominate artery (n = 3), and a 10 French cannula inserted into the graft for whole-body perfusion. Right atrial cannulation was obtained by dividing the anterior aspect of the diaphragm at the level of the xiphisternum, gaining easy access to the right atrial-inferior vena cava junction, without separating the sternal edges.
Discussion and Evaluation
All four infants successfully underwent their operations using SAC. In one case (2nd stage palliation for hypoplastic left heart syndrome) a cardiac injury occurred upon sternal reentry, but utilizing SAC, this was repaired without consequence.
Simplified aortic cannulation and direct right atrial cannulation may be obtained without dividing the sternum in complex reoperative infant surgeries, without making additional incisions. This may be life-saving in reoperative cardiac injuries in small infants.
Simplified Aortic Cannulation (SAC), wherein the innominate artery is used as the arterial inflow site rather than the ascending aorta, has made a significant impact on the conduct of complex operations for congenital heart disease, such as the Sano-Norwood operation, and cardiac operations in very small neonates or those with diminutive ascending aortas. [1, 2]
In young infants requiring resternotomy, the femoral vessels are too small to initiate cardiopulmonary bypass, and the neck has usually been accessed for venous lines. Consequently, few alternatives exist for the congenital cardiac surgeon, in cases at high risk for re-entry cardiac injury, or, in the event of uncontrollable re-entry injury having occurred. Some advocate more proximal, but still "peripheral" cannulation, such as iliac access via retroperitoneal exposure, but this is requires a separate incision, and is time-consuming .
In the current era, there is an increasing volume of young infants aged 2–4 months who require resternotomy, often with systemic pressures in their right ventricle, (e.g., hypoplastic left heart syndrome [HLHS], coming for 2nd stage), or with right ventricular-to-pulmonary artery conduits in close proximity to the back of the sternum (s/p Sano-Norwood operation), or in whom the ascending aorta is difficult to access expeditiously (s/p arterial switch operation [ASO] with LeCompte maneuver).
We describe a very useful technique which may be life-saving in these situations. We propose to broaden the indications for SAC to include reoperations, as the cannulation can be performed prior to even initiating the resternotomy, minimizing the effects of unintended entry into mediastinal structures.
Discussion and Evaluation
We have successfully used this technique in 4 infants between January and May, 2007. Two patients (3 months old and 4 months old) had HLHS and were undergoing 2nd stage palliation. In the first, the neoaorta was injured during reentry and CPB was initiated using this technique and the cardiac injury repaired. In the other, the Sano (right ventricle-to-pulmonary artery) conduit was embedded in the underside of the sternum, and could not be safely freed during the re-sternotomy. The third patient (1 year old) had undergone numerous previous operations elsewhere for complications of arterial switch operation with LeCompte maneuver for Taussig-Bing anomaly. The patient had been catheterized numerous times and the femoral vessels were at best tenuous. The patient had supra-systemic pressures in the pulmonary arteries which were in close proximity to the back of the sternum. This technique was utilized for this, the patient's fifth sternotomy. The last patient had a resternotomy for Ebstein's anomaly, and the huge, very thin-walled right atrium was not only adherent to the sternum, but completely obscuring the ascending aorta. This technique was successfully utilized in all four patients.
We use Simplified Aortic Cannulation routinely for complex congenital heart surgery, especially in very small neonates and those with small ascending aortas, or in whom the ascending aorta needs repair (e.g., aorto-pulmnoary window). It allows good arterial access in situations where the aorta is either too diminutive to accept a sufficiently sized cannula, or in cases where it is advantageous to avoid placing a cannula in the ascending aorta in close proximity to the area of reconstruction. Also, it provides a means for antegrade cerebral perfusion in situations where extensive aortic reconstruction would otherwise necessitate prolonged periods of circulatory arrest. Our previous experience with 86 neonates operated on at the University of Oklahoma and University of Alabama at Birmingham demonstrated no postoperative distortion or thrombotic complications with the innominate artery , underscoring the safety of this approach.
Recently, we have expanded our utilization of SAC to include reoperative cases, where the risk of sternal reentry injuries is high, or in which inadvertent sternal reentry injuries have occurred requiring the initiation of CPB in infants not suitable for femoral cannulation. We have found it to be an extremely helpful adjunct to the congenital heart surgeon in reoperative complex cardiac surgery. The technique is simple, it does not require a separate incision, and the exposure is expeditious and can be life-saving in difficult re-entry situations. The technique may be used in older patients with equal ease, and may provide the congenital cardiac surgeon with a viable alternative strategy in the operating room.
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