Orthotopic organ transplantation for end-stage heart and lung failure is a modality of treatment that is increasingly applied. With experience spanning multiple decades, we have now expanded thoracic transplantation to include higher-risk recipients and donors. Currently, over 4000 heart transplants, over 3000 lung transplants, and between 60 and 100 combined heart-lung transplants are performed annually worldwide.1,2
Transesophageal echocardiography (TEE) plays an essential role in the perioperative care of patients presenting for thoracic organ transplantation. In heart transplantation, TEE assists in the donor organ selection process, perioperative management, and post-transplant evaluation of recipients. Patients undergoing lung transplantation may demonstrate sequelae of respiratory failure, most commonly pulmonary hypertension and right ventricular dysfunction. TEE is utilized during lung transplantation to assess pre-procedure cardiac function, assess intraoperative hemodynamic changes, and evaluate the anastomotic sites.
As a result of continued organ shortages, the rate of heart transplantation has remained relatively constant over the past decade.3 The most common indications for heart transplantation include nonischemic (54%) and ischemic cardiomyopathy (37%).1 Transplantation in high-risk recipients with comorbid diseases such as diabetes with end-organ dysfunction, renal dysfunction, and advanced age (>65 years old) is common. Median survival after heart transplantation is 11 years, although recipients that survive the first year post-transplant have a median survival of 13 years.1
In order to accurately assess cardiac allograft anatomy and physiology, the echocardiographer needs to understand the surgical procedure and appreciate the changes that normally occur in the transplanted heart. Two techniques are typically used for heart transplantation, biatrial or bicaval, named according to the location of the anastomoses. The standard, or biatrial, technique, originally described by Lower and Shumway,4 was the primary method for nearly 30 years. In this technique, the recipient's right atrium (RA) is divided through the body, leaving its posterior aspect in situ. Additionally, most of the native left atrium (LA) and interatrial septum are left in situ. The inferior vena cava (IVC), superior vena cava (SVC), and pulmonary venous inflow tracts are left undisturbed. In the donor heart, an LA cuff is created by incising around the pulmonary vein orifices, whereas the RA cuff is created by incising through the IVC orifice and extending the incision up toward the base of the RA appendage. The donor RA and LA cuffs are then attached to the recipient's RA and LA, respectively.
In the bicaval technique, the recipient's entire RA is removed by dividing both the IVC and SVC proximal to the RA, creating IVC and SVC cuffs. The posterior aspect of the LA is left in situ, leaving the native pulmonary vein inflow sites intact. The donor heart is then attached via the IVC and SVC cuffs and LA suture line. For both biatrial and bicaval techniques, the donor's pulmonary artery and ascending aorta are anastomosed similarly.