Double Superior Vena Cava Cannulation for Venous Drainage in Minimally Invasive Aortic Valve Surgery

Introduction

There are two main approaches to venous cannulation for cardiopulmonary bypass in minimally invasive aortic valve surgery. The first is cannulation of the right atrial appendage with a two stage venous cannula, as in full a sternotomy, which enables the best venous drainage. All surgeons are familiar with this approach; however, the large cannula occupies space, lifts the right atrial appendage, and limits access to the aortic root. Furthermore, the right atrium may not be visible when the access is a right mini-thoracotomy through the second right intercostal space or upper partial sternotomy through the third intercostal space. Some surgeons tunnel the cannula below the xiphoid, which enhances the access to the aortic root (1). The second approach is percutaneous femoral venous cannulation. This approach is the best in terms of space available to the surgeon. Femoral venous cannulation is applicable to both mini-sternotomy and mini-thoracotomy approaches. However, it adds a wound in the groin, percutaneous cannulas are more expensive, and in some patients the passage of the wire to the right atrium may not be possible. The authors present a technique of double superior venous cannulation, which is applicable to both mini-sternotomy and thoracotomy, provides adequate venous drainage, and does not restrict the access to the ascending aorta and the aortic root.

Figure 1: Double SVC cannulation technique.

Technique

After opening the pericardium, the superior vena cava (SVC) is mobilized cranially to gain adequate length. Heparin is given, and the aorta is cannulated in the standard fashion. Two 4-0 Prolene purse string sutures are placed on the anterior surface of the SVC, high enough to avoid damage to the sinoatrial node. The SVC is then cannulated with two 22 French cannulas (Medtronic, Inc., Minneapolis, MN, USA). First, a right angle cannula is placed through the cranial purse string and directed toward the head of the patient. Then a straight cannula is placed through the caudal purse string into the right atrium (Figs. 1 and 2). Usually, the assistant needs to move the ascending aorta to allow cannulation of the SVC. The cardiopulmonary bypass is then started and when on full flow, the perfusionist is asked to empty the heart by adding vacuum assist (-40 to -60 mmHg). With adequate venous drainage, the right atrium, right ventricle, and pulmonary artery collapse, and the aortic cross-clamp can be applied. Sometimes the venous drainage is not optimal and the straight venous cannula needs to be repositioned. Typically, the 7-8 cm depth of insertion of the straight SVC cannula into the right atrium provides adequate venous drainage. The two thin and pliable venous cannulas are then positioned at the right upper corner of the mini sternotomy (Fig. 2), or in the lateral corner of the thoracotomy, allowing unrestricted access to the aortic root and the ascending aorta.

Figure 2: Operative setup. 

Conclusion

This technique has been used successfully in over 300 cases of minimally invasive aortic valve and ascending aortic surgery in the authors' center. None of the patients experienced damage to the sinoatrial node or needed conversion to a different type of venous drainage. The technique is quick and simple, uses standard surgical instrumentation, and can be applied in all cases of minimally invasive surgery of the ascending aorta and the aortic valve.

References

1. Borger MA. Minimally invasive rapid deployment Edwards Intuity aortic valve implantation. Annals of Cardiothoracic Surgery 2014;4:193-195.