- Email: [email protected]
Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt
CASE REPORT
Case Report
Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt Budhaditya Chakraborty, MS, Sachin Talwar, MCh, Shiv Kumar Choudhary, MCh, Shyam Sunder Kothari, DM and Balram Airan, MCh ∗ Cardiothoracic Sciences Center, All India Institute of Medical Sciences, New Delhi, India
We present our experience with a patient in whom a homograft conduit was used to connect the superior vena cava (SVC) to the right pulmonary artery (RPA) in a functionally univentricular heart where corrective repair was impossible. (Heart, Lung and Circulation 2007;16:52–54) © 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved. Keywords. Univentricular heart; Aortic homograft; Superior vena vava
Introduction
U
se of homograft conduits has been described in patients undergoing the extracardiac Fontan operation to route the inferior vena cava to the pulmonary artery.1,2 However, we were forced to use a homograft conduit to connect the superior vena cava (SVC) to the right pulmonary artery (RPA) in a patient with a functionally univentricular heart where corrective repair was impossible.
Case Report A 14-year-old boy presented with progressively increasing dyspnoea and cyanosis since childhood. In addition, he had two episodes of haemoptysis six months prior to presentation. The patient’s oxygen saturation on pulse oximetry ranged from 58 to 62% on room air. On investigation he was found to have double outlet right ventricle with a large non committed ventricular septal defect (VSD), severe pulmonary stenosis with confluent good sized pulmonary arteries with the right pulmonary larger (RPA) than the left pulmonary artery (LPA). There was evidence of total anomalous pulmonary venous return through a dilated azygous vein draining into the SVC and through it into the right atrium. A bidirectional Glenn shunt was planned as the VSD was unroutable. At operation, the azygous vein was opening into the SVC anterolaterally. The common chamber where all the pulmonary veins opened was lying posterior to the right Received 29 March 2006; received in revised form 10 July 2006; accepted 13 July 2006; available online 22 December 2006 ∗ Correspondence to: Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi 110029, India. Tel.: +91 11 26588500; fax: +91 11 26588663. E-mail address: iactscon [email protected] (B. Airan).
pulmonary artery and draining into the azygous vein (Fig. 1a). Cardiopulmonary bypass (CPB) was established by cannulation of the right atrial appendage and innominate vein. Despite maximal mobilisation of the SVC and the pulmonary arteries, the length of the SVC was inadequate to reach the RPA to enable the Glenn shunt. The SVC was therefore transected obliquely just above the attachment of the azygous vein and the cardiac end was oversewn thus directing all the pulmonary drainage into the right atrium. In order to enable the SVC flow to be directed to the RPA, a cryopreserved, non-valved aortic homograft conduit (1.2 cm radius and 5.8 cm long) was interposed. Superiorly the homograft was sutured end to end to the SVC using continuous polypropylene suture and inferiorly it was sutured end to side to the RPA using a continuous suture. The antergrade flow through the main pulmonary artery was preserved (Fig. 1b). The patient was weaned off CPB with satisfactory haemodynamics. The post operative course was uneventful and the patient was discharged on the seventh day. The oxygen saturation on pulse oximetry improved to 80–84% on room air. The course remained uneventful for the next year. However, after one year the patient had recurrence of the dyspnoea and cyanosis with systemic saturation of 68% on pulse oximetry. A repeat echocardiogram was unremarkable. However, cardiac catheterisation showed thrombosis of the right axillary and subclavian vein and SVC obstruction with formation of multiple collaterals. CT angiography was confirmatory and showed thrombosis in the homograft conduit with a blocked Glenn circuit (Fig. 2). At re-operation, CPB was established by elective cannulation of the femoral artery and vein prior to sternotomy. The entire pericardial cavity was covered by dense vascular adhesions which made dissection and delineation of the cardiac structures virtually impossible. With meticulous dissection, the tissue overlying the homograft conduit
© 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved.
1443-9506/04/$30.00 doi:10.1016/j.hlc.2006.07.004
Chakraborty et al. Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt
53 CASE REPORT
Heart, Lung and Circulation 2007;16:52–54
Figure 1. (a) The anatomy at operation. Note that the pulmonary venous confluence (PV) drains into the superior vena cava (SVC) through the azygous vein opening (arrow) behind the right pulmonary artery (RPA). (b) The anatomy after operation. The homograft conduit (H) is interposed between the SVC and RPA. LPA, left pulmonary artery; Ao, aorta.
was exposed. After placing stay sutures, the homograft was incised longitudinally on its anterior surface. Under low flow bypass, thrombectomy of the conduit was performed. The thrombus was completely evacuated successfully along with the remnant tissue debris and good retrograde bleed from the pulmonary arteries was seen. There were no kinks or anastomotic problems to account for the clot. The incision was then primarily closed using single
layered 6’0 polypropylene suture. Post operative course was uneventful with improvement of oxygen saturations and relief of symptoms. Post operative echocardiogram revealed good function of the Glenn circuit with good flow into the pulmonary arteries. Systemic saturation on pulse oximetry improved to above 80% consistently on room air. The patient was started on oral antiplatelets (aspirin) and anticoagulant therapy with warfarin; the international
Figure 2. CT angiogram after operation demonstrating the right (R) and left (L) pulmonary arteries and the homograft (arrow). The homograft is filled with thrombus.
54
Chakraborty et al. Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt
CASE REPORT
normalised ratio (INR) was maintained between 2.0 and 3.0. Ten months later, he continues to have a systemic saturation of over 85% and there is no evidence of thrombosis of the homograft.
Discussion A bidirectional Glenn shunt is carried out by a direct suture anastomosis between the SVC and the RPA in an end to side manner. The lie of the azygous vein and the anomalous pulmonary drainage into it presented a difficult problem. Initially we considered repair of the anomalous pulmonary venous connection with anastomosis of the confluence to the left atrium, and division of the draining vein, with Glenn in the usual fashion as it is a better alternative. However, because of the unusual anatomy and the location of the pulmonary venous chamber behind the right pulmonary artery with a very high drainage into the SVC, we were not able to gain an adequate length of the SVC to reach the RPA. We tried extensive mobilisation of the pulmonary arteries also to enable this, but were not successful. Therefore, it was considered that homograft interposition between the SVC and the RPA would be a safer option. The use of homograft conduits in the extracardiac Fontan operation has been described earlier,1,2 but these have been used primarily between the inferior vena cava and the right pulmonary artery. An extensive search of the English medical literature failed to reveal a similar instance of the use of homograft for SVC replacement in patients with a functionally univentricular heart. However, the use of aortic homograft as a replacement for SVC following its resection for superior vena cava syndrome has been reported earlier.3 Also, there are reports of use of other conduits for SVC replacement in patients with superior vena cava syndrome and lung cancer.4–7 The conduits used have consisted of aortic homograft, spiral vein grafts, custom-made pericardial tube, double velour polytetrafluoroethylene prosthesis, expanded polytetrafluoroethylene prosthesis and heterologous bovine prosthesis. The results obtained with the use of these prostheses are unclear and primarily dictated by the primary pathology (malignancy versus tuberculosis), rather than the graft itself.4–7 As in other parts of the vascular system, thrombosis of the grafts may be multifactorial and related to alterations in the lining of the graft, hypercoagulability and stasis. In our patient, the long length of the graft and failure to prescribe anticoagulants after the initial operation may have contributed to the thrombosis. Cryo-preserved homografts have the advantages of low immunogenecity and low risk of thrombosis as compared to prosthetic material. Spiral vein grafts may also be a suitable alternative and better than prosthesis because of a
Heart, Lung and Circulation 2007;16:52–54
smooth endothelial lining. Freedom from thrombosis with the use of spiral vein grafts has been observed for up to seven years. However, the disadvantages of using homografts (aortic/vein) are limited availability, requirements for facilities for banking and preservation and less size range.5,6 The advantages of the polytetrafluoroethylene graft are ready availability in all sizes, ease of implantation and less likelihood of compression. Up to five year followup of these patients is advisable and has demonstrated acceptable results.7 There have been reports of treatment of homograft thrombosis by anticoagulation, thrombolysis and percutaneous angioplasty.7 The results of any of these are variable and surgery with thrombectomy or conduit replacement has been the preferred option. We initially contemplated thrombolysis in our patient. However, reoperation was preferred because we thought we would perform thrombectomy of the homograft and also perform the completion total cavopulmonary connection by routing the inferior vena cava return into the right pulmonary artery. This was, however, rendered impossible by the dense adhesions. Therefore, only thrombectomy of the homograft conduit was carried out as a salvage procedure with a satisfactory outcome. As indicated earlier, no precedent of a similar case has been found in the literature search. We hope that with proper anticoagulation we should not encounter re-thrombosis of the homograft although the concern for its calcification in the long-term necessitating another re-operation persists.
References 1. Amodeo A, Galletti L, Marianeschi S, Picardo S, Giannico S, Di Renzi P, et al. Extracardiac Fontan operation for complex cardiac anomalies: seven years’ experience. J Thorac Cardiovasc Surg 1997;114:1020–30. 2. Laschinger JC, Redmond JM, Cameron DE, Kan JS, Ringel RE. Intermediate results of the extracardiac Fontan procedure. Ann Thorac Surg 1996;62:1261–7. 3. Ohri SK, Lawrence DR, Townsend ER. Homograft as a conduit for superior vena cava syndrome. Ann Thorac Surg 1997;64:531–3. 4. Spaggiari L, Galetta D, Veronesi G, Leo F, Gasparri R, Petrella F, et al. Superior vena cava replacement for lung cancer using a heterologous (bovine) prosthesis: preliminary results. J Thorac Cardiovasc Surg 2006;131:490–1. 5. Oyarzun JR, McCormick JR. Homograft and the superior vena cava syndrome. Ann Thorac Surg 1998;65:1836–7. 6. Billing JS, Sudarshan CD, Schofield PM, Murgatryod F, Wells FC. Aortic arch homograft as bypass conduit for superior vena cava obstruction. Ann Thorac Surg 2003;76:1296–7. 7. Magnan PE, Thomas P, Giudicelli R, Fuentes P, Branchereau A. Surgical reconstruction of the superior vena cava. Cardiovasc Surg 1994;2:598–604.
Case Report
Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt Budhaditya Chakraborty, MS, Sachin Talwar, MCh, Shiv Kumar Choudhary, MCh, Shyam Sunder Kothari, DM and Balram Airan, MCh ∗ Cardiothoracic Sciences Center, All India Institute of Medical Sciences, New Delhi, India
We present our experience with a patient in whom a homograft conduit was used to connect the superior vena cava (SVC) to the right pulmonary artery (RPA) in a functionally univentricular heart where corrective repair was impossible. (Heart, Lung and Circulation 2007;16:52–54) © 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved. Keywords. Univentricular heart; Aortic homograft; Superior vena vava
Introduction
U
se of homograft conduits has been described in patients undergoing the extracardiac Fontan operation to route the inferior vena cava to the pulmonary artery.1,2 However, we were forced to use a homograft conduit to connect the superior vena cava (SVC) to the right pulmonary artery (RPA) in a patient with a functionally univentricular heart where corrective repair was impossible.
Case Report A 14-year-old boy presented with progressively increasing dyspnoea and cyanosis since childhood. In addition, he had two episodes of haemoptysis six months prior to presentation. The patient’s oxygen saturation on pulse oximetry ranged from 58 to 62% on room air. On investigation he was found to have double outlet right ventricle with a large non committed ventricular septal defect (VSD), severe pulmonary stenosis with confluent good sized pulmonary arteries with the right pulmonary larger (RPA) than the left pulmonary artery (LPA). There was evidence of total anomalous pulmonary venous return through a dilated azygous vein draining into the SVC and through it into the right atrium. A bidirectional Glenn shunt was planned as the VSD was unroutable. At operation, the azygous vein was opening into the SVC anterolaterally. The common chamber where all the pulmonary veins opened was lying posterior to the right Received 29 March 2006; received in revised form 10 July 2006; accepted 13 July 2006; available online 22 December 2006 ∗ Correspondence to: Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi 110029, India. Tel.: +91 11 26588500; fax: +91 11 26588663. E-mail address: iactscon [email protected] (B. Airan).
pulmonary artery and draining into the azygous vein (Fig. 1a). Cardiopulmonary bypass (CPB) was established by cannulation of the right atrial appendage and innominate vein. Despite maximal mobilisation of the SVC and the pulmonary arteries, the length of the SVC was inadequate to reach the RPA to enable the Glenn shunt. The SVC was therefore transected obliquely just above the attachment of the azygous vein and the cardiac end was oversewn thus directing all the pulmonary drainage into the right atrium. In order to enable the SVC flow to be directed to the RPA, a cryopreserved, non-valved aortic homograft conduit (1.2 cm radius and 5.8 cm long) was interposed. Superiorly the homograft was sutured end to end to the SVC using continuous polypropylene suture and inferiorly it was sutured end to side to the RPA using a continuous suture. The antergrade flow through the main pulmonary artery was preserved (Fig. 1b). The patient was weaned off CPB with satisfactory haemodynamics. The post operative course was uneventful and the patient was discharged on the seventh day. The oxygen saturation on pulse oximetry improved to 80–84% on room air. The course remained uneventful for the next year. However, after one year the patient had recurrence of the dyspnoea and cyanosis with systemic saturation of 68% on pulse oximetry. A repeat echocardiogram was unremarkable. However, cardiac catheterisation showed thrombosis of the right axillary and subclavian vein and SVC obstruction with formation of multiple collaterals. CT angiography was confirmatory and showed thrombosis in the homograft conduit with a blocked Glenn circuit (Fig. 2). At re-operation, CPB was established by elective cannulation of the femoral artery and vein prior to sternotomy. The entire pericardial cavity was covered by dense vascular adhesions which made dissection and delineation of the cardiac structures virtually impossible. With meticulous dissection, the tissue overlying the homograft conduit
© 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved.
1443-9506/04/$30.00 doi:10.1016/j.hlc.2006.07.004
Chakraborty et al. Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt
53 CASE REPORT
Heart, Lung and Circulation 2007;16:52–54
Figure 1. (a) The anatomy at operation. Note that the pulmonary venous confluence (PV) drains into the superior vena cava (SVC) through the azygous vein opening (arrow) behind the right pulmonary artery (RPA). (b) The anatomy after operation. The homograft conduit (H) is interposed between the SVC and RPA. LPA, left pulmonary artery; Ao, aorta.
was exposed. After placing stay sutures, the homograft was incised longitudinally on its anterior surface. Under low flow bypass, thrombectomy of the conduit was performed. The thrombus was completely evacuated successfully along with the remnant tissue debris and good retrograde bleed from the pulmonary arteries was seen. There were no kinks or anastomotic problems to account for the clot. The incision was then primarily closed using single
layered 6’0 polypropylene suture. Post operative course was uneventful with improvement of oxygen saturations and relief of symptoms. Post operative echocardiogram revealed good function of the Glenn circuit with good flow into the pulmonary arteries. Systemic saturation on pulse oximetry improved to above 80% consistently on room air. The patient was started on oral antiplatelets (aspirin) and anticoagulant therapy with warfarin; the international
Figure 2. CT angiogram after operation demonstrating the right (R) and left (L) pulmonary arteries and the homograft (arrow). The homograft is filled with thrombus.
54
Chakraborty et al. Use of Aortic Homograft Conduit in Bidirectional Glenn Shunt
CASE REPORT
normalised ratio (INR) was maintained between 2.0 and 3.0. Ten months later, he continues to have a systemic saturation of over 85% and there is no evidence of thrombosis of the homograft.
Discussion A bidirectional Glenn shunt is carried out by a direct suture anastomosis between the SVC and the RPA in an end to side manner. The lie of the azygous vein and the anomalous pulmonary drainage into it presented a difficult problem. Initially we considered repair of the anomalous pulmonary venous connection with anastomosis of the confluence to the left atrium, and division of the draining vein, with Glenn in the usual fashion as it is a better alternative. However, because of the unusual anatomy and the location of the pulmonary venous chamber behind the right pulmonary artery with a very high drainage into the SVC, we were not able to gain an adequate length of the SVC to reach the RPA. We tried extensive mobilisation of the pulmonary arteries also to enable this, but were not successful. Therefore, it was considered that homograft interposition between the SVC and the RPA would be a safer option. The use of homograft conduits in the extracardiac Fontan operation has been described earlier,1,2 but these have been used primarily between the inferior vena cava and the right pulmonary artery. An extensive search of the English medical literature failed to reveal a similar instance of the use of homograft for SVC replacement in patients with a functionally univentricular heart. However, the use of aortic homograft as a replacement for SVC following its resection for superior vena cava syndrome has been reported earlier.3 Also, there are reports of use of other conduits for SVC replacement in patients with superior vena cava syndrome and lung cancer.4–7 The conduits used have consisted of aortic homograft, spiral vein grafts, custom-made pericardial tube, double velour polytetrafluoroethylene prosthesis, expanded polytetrafluoroethylene prosthesis and heterologous bovine prosthesis. The results obtained with the use of these prostheses are unclear and primarily dictated by the primary pathology (malignancy versus tuberculosis), rather than the graft itself.4–7 As in other parts of the vascular system, thrombosis of the grafts may be multifactorial and related to alterations in the lining of the graft, hypercoagulability and stasis. In our patient, the long length of the graft and failure to prescribe anticoagulants after the initial operation may have contributed to the thrombosis. Cryo-preserved homografts have the advantages of low immunogenecity and low risk of thrombosis as compared to prosthetic material. Spiral vein grafts may also be a suitable alternative and better than prosthesis because of a
Heart, Lung and Circulation 2007;16:52–54
smooth endothelial lining. Freedom from thrombosis with the use of spiral vein grafts has been observed for up to seven years. However, the disadvantages of using homografts (aortic/vein) are limited availability, requirements for facilities for banking and preservation and less size range.5,6 The advantages of the polytetrafluoroethylene graft are ready availability in all sizes, ease of implantation and less likelihood of compression. Up to five year followup of these patients is advisable and has demonstrated acceptable results.7 There have been reports of treatment of homograft thrombosis by anticoagulation, thrombolysis and percutaneous angioplasty.7 The results of any of these are variable and surgery with thrombectomy or conduit replacement has been the preferred option. We initially contemplated thrombolysis in our patient. However, reoperation was preferred because we thought we would perform thrombectomy of the homograft and also perform the completion total cavopulmonary connection by routing the inferior vena cava return into the right pulmonary artery. This was, however, rendered impossible by the dense adhesions. Therefore, only thrombectomy of the homograft conduit was carried out as a salvage procedure with a satisfactory outcome. As indicated earlier, no precedent of a similar case has been found in the literature search. We hope that with proper anticoagulation we should not encounter re-thrombosis of the homograft although the concern for its calcification in the long-term necessitating another re-operation persists.
References 1. Amodeo A, Galletti L, Marianeschi S, Picardo S, Giannico S, Di Renzi P, et al. Extracardiac Fontan operation for complex cardiac anomalies: seven years’ experience. J Thorac Cardiovasc Surg 1997;114:1020–30. 2. Laschinger JC, Redmond JM, Cameron DE, Kan JS, Ringel RE. Intermediate results of the extracardiac Fontan procedure. Ann Thorac Surg 1996;62:1261–7. 3. Ohri SK, Lawrence DR, Townsend ER. Homograft as a conduit for superior vena cava syndrome. Ann Thorac Surg 1997;64:531–3. 4. Spaggiari L, Galetta D, Veronesi G, Leo F, Gasparri R, Petrella F, et al. Superior vena cava replacement for lung cancer using a heterologous (bovine) prosthesis: preliminary results. J Thorac Cardiovasc Surg 2006;131:490–1. 5. Oyarzun JR, McCormick JR. Homograft and the superior vena cava syndrome. Ann Thorac Surg 1998;65:1836–7. 6. Billing JS, Sudarshan CD, Schofield PM, Murgatryod F, Wells FC. Aortic arch homograft as bypass conduit for superior vena cava obstruction. Ann Thorac Surg 2003;76:1296–7. 7. Magnan PE, Thomas P, Giudicelli R, Fuentes P, Branchereau A. Surgical reconstruction of the superior vena cava. Cardiovasc Surg 1994;2:598–604.