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Interact CardioVasc Thorac Surg 2005;4:499-501. doi:10.1510/icvts.2004.103218 © 2005 European Association of Cardio-Thoracic Surgery
Bidirectional Glenn shunt with concomitant placement of extra-cardiac graft – preparatory procedure for the future total cavo-pulmonary connectionDepartment of Pediatric Cardiovascular Surgery, Osaka City General Hospital, 2-13-22 Miyakojimahondori, Miyakojimaku, Osaka 534-0021, Japan Received 6 December 2004; received in revised form 13 May 2005; accepted 6 July 2005
*Corresponding author. Tel.: +81-6-6929-1221; fax: +81-6-6929-1091.
We herein present bidirectional Glenn shunt and concomitant placement of extra-cardiac graft with an advantage of preparation for a later extra-cardiac total cavo-pulmonary connection, which was successfully performed for seven children with a univentricular heart.
Key Words: Bidirectional Glenn shunt; Extra-cardiac graft; Extra-cardiac total cavo-pulmonary connection; Less invasive surgery
Extra-cardiac total cavo-pulmonary connection (TCPC) has been accepted worldwide as a definitive repair for patients with a univentricular heart, and the surgical result is better since staged strategy was induced [1,2]. We have carried out bidirectional Glenn shunt with concomitant placement of extra-cardiac graft, with an ad- vantage of preparation for a later extra-cardiac TCPC operation, since February 2003 to make the extra-cardiac TCPC simpler.
Our procedure consists of bidirectional cavo-pulmonary shunting, connecting extra-cardiac graft to the right pulmonary artery, and establishing a small central shunt from the ascending aorta to the graft (Fig. 1).
Under general anesthesia, midline skin incision and median sternotomy were done. After dissection around the heart, cardio-pulmonary bypass was established. The azygos vein was ligated. The superior caval vein was divided at the level of the right pulmonary artery. The atrial end of the vein was closed directly. After clamping the right pulmonary artery, the superior caval vein was anastomosed with the right pulmonary artery. Next, a Gore Tex graft 14 or 16 mm in diameter was anastomosed with the caudal surface of the right pulmonary artery in an end-to-side fashion. The other end of the graft was closed directly. Continuity between the ascending aorta and the graft was established using a small Gore Tex shunt 3.5–4 mm in diameter, to prevent clot formation inside the graft and to supply hepatic blood flow to both the lungs. The patient was weaned from the cardiopulmonary bypass. The caudal end of the graft was fixed with the diaphragm to prevent it from coming up. Extra-cardiac TCPC was carried out approximately 6 months to 1 year after the surgery. After re-sternotomy, limited dissection around the inferior caval vein, the lower part of the atrium and the extra-cardiac graft anastomosed at the previous surgery, central shunt and the ascending aorta was done. No more dissection was needed, especially around the right pulmonary artery. The central shunt was divided. Partial cardiopulmonary bypass was established between the ascending aorta and the inferior caval vein. Arterial cannula can be directly inserted into the ascending aorta, but we could also use the central shunt divided as an arterial cannula (Fig. 2). After cutting the lower part of the extra-cardiac graft, another venous cannula was inserted into the superior caval vein through the orifice of the graft. Ventricular fibrillation was induced. The inferior caval vein was divided carefully so as not to injure the atrio-ventricular valve and the pulmonary veins. After the atrial end of the inferior caval vein was directly closed, the fibrilator was stopped. Cannulae in the superior caval vein were removed, and the caudal end of the extracardiac graft was anastomosed with the inferior caval vein in an end-to-end fashion. The patient was weaned from the bypass. In patients with hypertension of the superior caval vein, fenestration could be created using the distal part of the central shunt (Fig. 2).
Our procedure has been carried out for seven children, aged from 7 months to 3 years (median age of 16 months), with a univentricular heart, since February 2003.
There was no early or late death after our procedure. Extra-cardiac TCPC was successfully carried out without adding fenestration in all seven patients. Operative time and CPB time of our procedure with preparatory placement of extra-cardiac graft did not significantly differ from those of conventional bidirectional Glenn shunt (290±55 vs. 258±81 min, P=0.16 and 134±23 vs. 121±74 min, P=0.22). However, these values at TCPC completion after our procedure were significantly shorter than those after conventional bidirectional Glenn shunt (196±30 vs. 307±107 min, P=0.01 and 55±14 vs. 121±61 min, P=0.01). No nerve palsy, sinus node dysfunction, nor chylothorax occurred in any of the patients.
The hemi-Fontan operation is conceived as a means of anticipation of eventual completion of a modified Fontan operation with an atrio-pulmonary connection by anastomosing the right atrium with the pulmonary artery [3]. At the Fontan completion, no dissection around the pulmonary artery is required [3]. Our procedure performs a role in anticipation of eventual completion of the extra-cardiac TCPC with preparatory anastomosis between extra-cardiac graft and the pulmonary artery. No dissection around the pulmonary artery and the superior caval vein is required. Additional small shunt is provided with a small artificial tube from the ascending aorta to the graft, which might load a small volume of work to the ventricle with maintaining a good growth of pulmonary vascular bed [4]. This procedure has some limitations about graft size and patients' age. To establish the large extra-cardiac graft 16 mm in diameter, the operation should be carried out at the age of 6 months. Patients aged more than 6 months would be candidates for this procedure. Fontan operation for hypoplastic left heart syndrome has specific problems of coronary blood flow, which is sometimes impaired during surgical dissection around the right pulmonary artery. The Damus-Kaye-Stansel procedure [5], carried out with bidirectional Glenn shunt for subaortic stenosis with a univentricular heart, also provokes heavy adhesion around the aortic root and the pulmonary artery. Especially in these specific patients, dissection around the pulmonary artery is sometimes time-consuming. Our procedure might perform a role to simply establish an extra-cardiac TCPC. Our concept of this procedure would be to establish an anastomosis between extra-cardiac graft and the pulmonary artery before severe adhesion around them is provoked, rather than that much effort to dissect around them is offset from the Fontan completion to bidirectional Glenn shunt. Similarly, the phrenic nerve palsy should also be avoided especially after the Fontan operation. Chylothrax sometimes occurs after the Fontan operation, related with dissection around the superior caval vein. Sinus node dysfunction after the Fontan operation has been reported to be related with staged Fontan and dissection [6]. Furthermore, this procedure is easy to be taken down for the failed Fontan patients as well. When the fenestration is needed, we can use a central shunt established at the previous Glenn procedure, as a fenestration tube between the extra-cardiac graft and the atrium. Bidirectional Glenn shunt with preparatory concomitant placement of extra-cardiac graft might be a good option for selected patients with a univentricular heart, making the future extra-cardiac total cavo-pulmonary connection simpler.
Author: Jose Ma Caffarena (Children's Hospital San Joan de Deu, Barcelona, Spain) eComment: Kawahira et al. describe a new technique as a preparatory procedure to a future extracardiac Fontan procedure at the time of bidirectional Glenn anastomosis. Conceptually, this technique is the extracardiac version of the hemi-fontan procedure for intracardiac lateral tunnel operation. However, this preparatory procedure has several potential drawbacks related to the graft. The authors have used conduits of very small size, no bigger than 16 mm in diameter, due to the young age of the patients going to the bidirectional Glenn shunt. It supposes a conduit very small for the long-term function of the Fontan operation, being advised conduits in the range of 20–22 mm in diameter and patients weighing around 15 kg. The second area of concern is the high thrombogenic surface of a non-functioning conduit connected to a venous circuit, so anticoagulation must be necessary to try to avoid massive thrombus formation. The authors propose to make a shunt between the aorta and the graft to avoid thrombus formation, which is cumbersome, time-consuming and exposed to thrombosis at any moment. Moreover, the flow of this shunt is directed through the conduit against the Glenn shunt making cavopulmonary blood flow harder and increasing superior vein cava pressure. It is my opinion that a complete graft interposition during a third stage operation is the best choice for these patients.
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Abstract
1. Introduction
