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Homograft Saphenous Vein for Facilitating Arterial Cannulation in a Neonate
Homograft Saphenous Vein for Facilitating Arterial Cannulation in a Neonate Sachin Talwar, MCh, Anand Mishra, MCh, Shiv Kumar Choudhary, MCh, and Balram Airan, MCh Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi, India
I
n small neonates, a small ascending aorta can render arterial cannulation difficult and produce significant gradients at the site of cannulation after the aortic cannula is removed and the pursestring suture is tied. At the same time, the cannula itself may obstruct the aorta before, during, and after cardiopulmonary bypass contributing to unstable hemodynamics, or preferential and unequal flow of blood. Ultimately, this complicates the process of weaning the patient from cardiopulmonary bypass at the conclusion of the procedure. To overcome these difficulties, in patients with extremely small aorta, we have used an alternative means of aortic cannulation, which is simple and reproducible.
Technique A standard median sternotomy is performed. Thymus gland is partially or completely excised. The innominate artery is dissected out cephalad and looped with vessel loop. Systemic heparinization is achieved by administration of heparin (3 mg/Kg). A side-biting curved vascular clamp is applied to the innominate artery and a longitudinal arteriotomy is made in between stay sutures. A homograft saphaneous vein is anastomosed end-to-side to the innominate artery using a continuous 7-0 polypropylene suture. The innominate artery is unclamped and the vein graft is flushed and a small bull-dog vascular clamp is applied to it. The vein graft is typically left as long as 3 to 5 cm. An 8-French or10-French arterial cannula (Biomedicus; Medtronic Inc, Minneapolis, MN) is inserted into the end of vein graft and a ligature is tied around the vein to secure the cannula. This cannula is now connected to the arterial side of the bypass circuit,
Accepted for publication July 11, 2008. Address correspondence to Dr Airan, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, 110029, India; e-mail: [email protected].
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
and the air was removed in the usual fashion. Venous cannulation was performed in the usual manner and cardiopulmonary bypass was established. The remainder of the operation proceeds in the usual manner. At the completion of the procedure, after the heparin has been reversed, the graft is clipped close to and parallel with the innominate artery, thus avoiding placing sutures on the innominate artery. Extra length of the homograft vein is trimmed.
Comment The technique of innominate artery cannulation was first reported by Pigula and colleagues [1] in their report on the use of low-flow cerebral perfusion during neonatal aortic arch reconstruction. Subsequently, Tweddell and colleagues [2] used it for initial arterial cannulation and retrograde cerebral perfusion with later conversion to the innominate artery to right pulmonary shunt in neonates undergoing the Norwood procedure. Knott-Craig and colleagues [3], labeled it simplified aortic cannulation. In all three of these reports, a polytetrafluoroethylene graft was used. The advantages are the ease of cannulation, avoiding residual gradients at the cannulation site, and a more accessible length of the aorta. As described by Pigula and colleagues [1] Tweddell [2], regional cerebral perfusion can be performed safely with this technique and total circulatory arrest can be avoided. The advantage of using the homograft saphenous vein for this purpose is the ease of suturing and lack of needlehole bleeding from the vein, which may be cumbersome when a prosthetic graft is used. In addition, we procure this vein segment from our own homograft valve bank, so that it is inexpensive. We deliberately keep a long length of the vein to perform complex surgeries expeditiously without cumbersome cannula obstructing the field. The only disadvantage of a homograft vein as compared with polytetrafluoroethylene is limited availability. However, we have overcome this largely by preserving any extra segments of saphenous veins remaining at the end of coronary artery bypass grafting and by preserving veins from live brain-dead donors who are candidates for organ donation. The details of homograft preservation and banking have been described in detail in our prior publication [4]. Although we have the facility for cryopreservation of heart valves, we use antibiotic preservation for homograft veins. After rinsing the veins with 500 mL 0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2008.07.032
FEATURE ARTICLES
A simplified technique of arterial cannulation in neonates with diminutive aorta is presented. The technique is simple, inexpensive, and reproducible. (Ann Thorac Surg 2009;87:969 –70) © 2009 by The Society of Thoracic Surgeons
970
HOW TO DO IT TALWAR ET AL NEONATAL AORTIC CANNULATION
cold saline to remove any blood, these veins are stored in sterile filtered nutrient tissue culture medium (Hank’s solution). To every 1 L of this solution, the following antibiotics are added: cefoxitin (250 mg), lincomycin (120 mg), polymyxin B (100 mg), vancomycin (50 mg), and nystatin (1 million units). The N-2-hydroxyethylpiperazine-N=-2-ethanesulfonic acid (HEPES) buffer is added to maintain pH between 6.6 and 7.0. Sterile solution (100 mL) is added to each homograft for storage at 4° C. These antibiotic preserved homograft veins are used within 45 days. Because we harvest and preserve the vein ourselves, without involving any commercial firms, we are able to minimize the cost of this procedure.
Ann Thorac Surg 2009;87:969 –70
References 1. Pigula FA, Nemoto EM, Griffith BP, Siewers RD. Regional low-flow perfusion provides cerebral circulatory support during neonatal aortic arch reconstruction. J Thorac Cardiovasc Surg 2000;119:331–9. 2. Tweddell JS. The Norwood procedure with an innominate to right pulmonary artery shunt. Oper Tech Thorac Cardiovasc Surg 2005;10:123– 40. 3. Knott-Craig CG, Pastuszko P, Overholt ED. Simplified aortic cannulation (SAC)—a useful technique for neonates with small aortas. J Cardiothorac Surg 2006;1:13. 4. Choudhary SK, Srivastava S, Chander H, et al. Early experience with homograft valve banking. Asian Cardiovasc Thorac Ann 1997;5:137– 40.
FEATURE ARTICLES
I
n small neonates, a small ascending aorta can render arterial cannulation difficult and produce significant gradients at the site of cannulation after the aortic cannula is removed and the pursestring suture is tied. At the same time, the cannula itself may obstruct the aorta before, during, and after cardiopulmonary bypass contributing to unstable hemodynamics, or preferential and unequal flow of blood. Ultimately, this complicates the process of weaning the patient from cardiopulmonary bypass at the conclusion of the procedure. To overcome these difficulties, in patients with extremely small aorta, we have used an alternative means of aortic cannulation, which is simple and reproducible.
Technique A standard median sternotomy is performed. Thymus gland is partially or completely excised. The innominate artery is dissected out cephalad and looped with vessel loop. Systemic heparinization is achieved by administration of heparin (3 mg/Kg). A side-biting curved vascular clamp is applied to the innominate artery and a longitudinal arteriotomy is made in between stay sutures. A homograft saphaneous vein is anastomosed end-to-side to the innominate artery using a continuous 7-0 polypropylene suture. The innominate artery is unclamped and the vein graft is flushed and a small bull-dog vascular clamp is applied to it. The vein graft is typically left as long as 3 to 5 cm. An 8-French or10-French arterial cannula (Biomedicus; Medtronic Inc, Minneapolis, MN) is inserted into the end of vein graft and a ligature is tied around the vein to secure the cannula. This cannula is now connected to the arterial side of the bypass circuit,
Accepted for publication July 11, 2008. Address correspondence to Dr Airan, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, 110029, India; e-mail: [email protected].
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
and the air was removed in the usual fashion. Venous cannulation was performed in the usual manner and cardiopulmonary bypass was established. The remainder of the operation proceeds in the usual manner. At the completion of the procedure, after the heparin has been reversed, the graft is clipped close to and parallel with the innominate artery, thus avoiding placing sutures on the innominate artery. Extra length of the homograft vein is trimmed.
Comment The technique of innominate artery cannulation was first reported by Pigula and colleagues [1] in their report on the use of low-flow cerebral perfusion during neonatal aortic arch reconstruction. Subsequently, Tweddell and colleagues [2] used it for initial arterial cannulation and retrograde cerebral perfusion with later conversion to the innominate artery to right pulmonary shunt in neonates undergoing the Norwood procedure. Knott-Craig and colleagues [3], labeled it simplified aortic cannulation. In all three of these reports, a polytetrafluoroethylene graft was used. The advantages are the ease of cannulation, avoiding residual gradients at the cannulation site, and a more accessible length of the aorta. As described by Pigula and colleagues [1] Tweddell [2], regional cerebral perfusion can be performed safely with this technique and total circulatory arrest can be avoided. The advantage of using the homograft saphenous vein for this purpose is the ease of suturing and lack of needlehole bleeding from the vein, which may be cumbersome when a prosthetic graft is used. In addition, we procure this vein segment from our own homograft valve bank, so that it is inexpensive. We deliberately keep a long length of the vein to perform complex surgeries expeditiously without cumbersome cannula obstructing the field. The only disadvantage of a homograft vein as compared with polytetrafluoroethylene is limited availability. However, we have overcome this largely by preserving any extra segments of saphenous veins remaining at the end of coronary artery bypass grafting and by preserving veins from live brain-dead donors who are candidates for organ donation. The details of homograft preservation and banking have been described in detail in our prior publication [4]. Although we have the facility for cryopreservation of heart valves, we use antibiotic preservation for homograft veins. After rinsing the veins with 500 mL 0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2008.07.032
FEATURE ARTICLES
A simplified technique of arterial cannulation in neonates with diminutive aorta is presented. The technique is simple, inexpensive, and reproducible. (Ann Thorac Surg 2009;87:969 –70) © 2009 by The Society of Thoracic Surgeons
970
HOW TO DO IT TALWAR ET AL NEONATAL AORTIC CANNULATION
cold saline to remove any blood, these veins are stored in sterile filtered nutrient tissue culture medium (Hank’s solution). To every 1 L of this solution, the following antibiotics are added: cefoxitin (250 mg), lincomycin (120 mg), polymyxin B (100 mg), vancomycin (50 mg), and nystatin (1 million units). The N-2-hydroxyethylpiperazine-N=-2-ethanesulfonic acid (HEPES) buffer is added to maintain pH between 6.6 and 7.0. Sterile solution (100 mL) is added to each homograft for storage at 4° C. These antibiotic preserved homograft veins are used within 45 days. Because we harvest and preserve the vein ourselves, without involving any commercial firms, we are able to minimize the cost of this procedure.
Ann Thorac Surg 2009;87:969 –70
References 1. Pigula FA, Nemoto EM, Griffith BP, Siewers RD. Regional low-flow perfusion provides cerebral circulatory support during neonatal aortic arch reconstruction. J Thorac Cardiovasc Surg 2000;119:331–9. 2. Tweddell JS. The Norwood procedure with an innominate to right pulmonary artery shunt. Oper Tech Thorac Cardiovasc Surg 2005;10:123– 40. 3. Knott-Craig CG, Pastuszko P, Overholt ED. Simplified aortic cannulation (SAC)—a useful technique for neonates with small aortas. J Cardiothorac Surg 2006;1:13. 4. Choudhary SK, Srivastava S, Chander H, et al. Early experience with homograft valve banking. Asian Cardiovasc Thorac Ann 1997;5:137– 40.
FEATURE ARTICLES