Fig. 7.1
Biatrial compared to bicaval technique for cardiac transplantation (Reused with permission from Chen et al. [15])
Bicaval Technique
Operative Technique
Preparation of the recipient mediastinum is largely similar to the biatrial technique, with the major alteration being isolation of the SVC and IVC. The SVC is divided at the cavo-atrial junction, and the free wall of the right atrium is trimmed to allow for a sewing cuff just above the true IVC. The left atrial anastomosis is performed first, followed by only the posterior half of the IVC and PA anastomoses to reduce warm ischemic time. The aortic anastomosis is completed and the cross clamp is released as mentioned before. The remaining half of the PA anastomosis is completed. The donor SVC is then opened into the azygos vein to allow a large anastomosis and prevent postoperative stenosis. Care must be taken to keep the orientation of the SVC to avoid any kinking. The anterior anastomosis of the IVC is then completed. Weaning of the cardiopulmonary bypass is initiated and the operation is completed as discussed previously.
Heterotopic Heart Transplantation
Indications
Heterotopic heart transplantation is not widely utilized and is useful only for select circumstances. Accepted indications include [1] irreversible high pulmonary vascular resistance (PVR) in the recipient and [2] severe donor-recipient size mismatch. A potential third indication in the future may include xenotransplant bridging, as immuno-modulation advances may eventually make this a feasible option. As the donor graft serves to augment the native heart, it functions as a de facto bi-ventricular assist device. One advantage of the heterotopic technique is preservation of the native heart as a safety margin in case of graft dysfunction. Recognized complications include a high incidence of ventricular dysrhythmias, anatomic compression by the graft (e.g. right lung), and a high incidence of premature structural deterioration of the donor organ [11–13].
Operative Technique
Cardiopulmonary bypass is established and the right pleura is incised. An opening is made on the donor left atrium just below the interatrial groove, and this is anastomosed to a cuff of recipient right pulmonary vein. A longitudinal incision is then made on the recipient right atrium and extended to the SVC. The donor right atrium and SVC is similarly incised, and a running anastomosis is performed. The donor pulmonary artery and aorta are then anastomosed to their respective structures on the recipient in an end-to-side fashion; these connections often require prosthetic graft augmentation to provide adequate length [11]. An illustration of the technique is provided in Fig. 7.2.
Special Considerations
It is quite common for heart transplant recipients to require redo sternotomy, as many heart failure patients have undergone prior operations such as coronary artery bypass, valve replacement, mechanical circulatory support device implantation, prior heart transplant, or correction of congenital abnormality. Previous thoracic operations can significantly elevate the complexity and hazard of the surgical dissection, and may result in increased use of blood products and operative time. Any patient being considered for heart transplantation via redo sternotomy should have a preoperative CT scan of the chest performed as part of the preoperative workup, in order to better evaluate the intrathoracic anatomy (e.g. course of the inominate vein and proximity of the right ventricle to the sternum). At the time of implant surgery, the operative team must have a clearly defined strategy that should include strong consideration of alternative cannulation options, such as femoral or axillary artery cannulation. The IVC may be cannulated percutaneously via the femoral vein using a guide wire and serial dilators. Utilizing peripheral vascular access can allow for initiation of cardiopulmonary bypass prior to sternotomy.
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