Lung and heart–lung transplantation has emerged over the past several decades as an acceptable therapy for end-stage lung disease. Despite significant progress, lung transplantation remains a complex therapy that requires a multidisciplinary approach for successful outcomes. Moreover, it is increasingly clear that early postoperative events are associated with long-term complications. There are currently approximately 1800 and 70 patients awaiting lung and heart–lung transplant, respectively. In 2009, 1599 adult lung transplants were performed in the United States. In 2005, a new allocation policy was adopted in the United States. Patients are now assigned a Lung Allocation Score (LAS) based on clinical parameters. The score emphasizes transplant utility rather than wait-list time. It allows rapid allocation of organs to critically ill patients and decreasing allocation to less sick patients. As a result, patients are no longer listed just to accrue time. This has led to a significant reduction in the size of the active wait list (Fig. 11-1). The number of heart–lung transplant procedures has also declined.¹ Bilateral lung transplant has supplanted many of the indications. Nonetheless, a small group of patients remain excellent candidates for this unique procedure.

In 1963, James Hardy performed the first human lung transplant.² This right single-lung transplant recipient died in 18 days with a functioning allograft. After the introduction of cyclosporine, Reitz and colleagues at Stanford performed the first combined heart–lung transplant.³ In 1983, Joel Cooper successfully performed single-lung transplants in three patients.⁴ By 1992, bilateral sequential lung transplantation supplanted en bloc double lung transplant, marking the modern era of lung transplantation.

Simply stated, lung transplant is indicated in patients with end-stage lung disease, with the purpose of increasing survival and improving quality of life. Recipient selection is critically important and may be complex, given the range of pathologies in candidates.

There are a number of absolute contraindications to lung transplantation as defined by the International Society of Heart and Lung Transplantation (ISHLT).⁵ Patients should not have had a malignancy in the last 2 years, except for certain skin cancers. In patients with a history of cancer, a disease-free interval of at least 5 years is recommended. Candidates should not have untreatable end-organ dysfunction. This would include uncorrectable coronary artery disease, significant left-ventricular dysfunction, and end-stage liver disease. Patients with renal failure or significant insufficiency should not be considered unless combined with kidney transplant. Active viral infections are a contraindication and include hepatitis B, C, and HIV. Patients who are actively using tobacco or abusing other drugs or alcohol should not be considered for transplant and should be abstinent for at least 6 months. Finally, significant psychosocial problems preclude transplantation.

With improving results, several centers have been emboldened to offer lung transplantation to a wider spectrum of patients. As a result, there are several relative contraindications to lung transplantation, and each center must decide the importance of each. Initially, an age cutoff for lung transplant had been proposed; however, several centers have transplanted patients over the age of 70 years with reasonable results. The national experience in this age group, however, is poor. Nonetheless, the ISHLT guidelines have set 65 years as the upper limit, and advanced age as a relative contraindication. Severely limited functional status and obesity lead to poor outcomes, and patients should actively participate in rehabilitation programs if possible, maintaining a body mass index (BMI) <30. Long-term steroids after transplant make severe osteoporosis a relative contraindication.⁵

The ISHLT has established disease-specific guidelines summarized in Table 11-1. Controversy exists in transplantation for bronchoalveolar cell carcinoma. Since the disease recurs locally, lung transplantation has been used to treat these patients. Limited series have demonstrated acceptable short-term survival.⁶ Primary, diseases do not recur except in sarcoid.

There has been a significant liberalization of donor criteria over the past decade. The original criteria for what is considered a standard donor have given way to a more realistic set of criteria (Table 11-2). Ultimately, centers can accept or decline any organ for various reasons, but it is increasingly clear that donor characteristics have less to do with outcome than previously thought. Large database studies have found only donor tobacco use greater than 20 pack-years and age to be important risk factors.^7,8 Nonetheless, there are special considerations in lung transplantation. First, matching donor and recipient size is important. Oversized lungs can compromise hemodynamics early after transplant and have a long-term propensity of atelectasis. Height is clearly more important than weight, and gender is relevant when considering female recipients with fibrotic lung diseases. There are many ways to judge size matching ranging from simple height and weight ranges to estimating total lung capacity.⁹ A simple rule is to use donors who are no more than 4 inches in recipient height for most lung diseases. However, cystic fibrosis and chronic obstructive pulmonary disease (COPD) can usually accommodate much larger donor sizes (as much as 12 inches in difference). Moreover, oversized donors may be trimmed with multiple wedge resections or even anatomic resection ex vivo to allow transplantation in small recipients.

There has been growing interest in using non-heart beating donors (DCD) for lung transplant. Lungs remain metabolically stable without circulation for up to an hour when ventilated. As a result, DCD donors may yield functional lungs without brain death-related injury. The initial experience is acceptable but the number of actual donors added to the pool may be limited.¹⁰ Similarly, there is a growing experience with ex vivo perfusion of potential donors to rehabilitate unacceptable lungs.^11,12

When the recovery team arrives at the donor hospital, review of the imaging and documentation should be performed as well as the mechanics on the ventilator. Bronchoscopy should be performed by the recovery team to assess for intraluminal masses and secretion quality. Purulent secretions that cannot be cleared bronchoscopically represent a relative contraindication to donation.

After median sternotomy and opening of the pleural spaces, the lungs should be palpated for masses and the compliance assessed by simple observation. Frequently, obese donors will have much better mechanics when the chest is opened. The pericardium is then opened. The superior vena cava (SVC) should be mobilized completely to prevent injury to the right pulmonary artery. We prefer separation of the aorta and main PA as well. In donors with small atria, modest dissection of Sondergaard’s groove can help the right-sided left atrial cuff. A final arterial blood gas is obtained under these ideal conditions. If single-lung transplantation is planned, then blood gases may be obtained from individual pulmonary veins to asses each lung.

The main pulmonary artery should be cannulated with an angled 20-F aortic cannula. Some institutions strongly feel to direct the cannula toward the pulmonary valve to evenly distribute preservation solution, but we have not found this to be clinically important. Prior to cross-clamping, the teams should decide where venting of the left atrium should occur. If the heart is to be recovered, then the left atrial appendage is preferable. To preserve left atrial appendage function, some centers will rather incise along Sondergaard’s groove. The SVC is ligated. Prostaglandin is injected into the main pulmonary artery. The inferior vena cava (IVC) and left atrium are then vented. The aorta is cross-clamped, and the preservation solution is delivered. When a heart–lung bloc is recovered, both cardioplegia and pulmonary preservation solution are used.

During infusion of the preservation solution, we continue gentle ventilation with inspired oxygen and monitor the effluent from the left atrial venting site. We infuse 4 L antegrade in all donors. The donor heart is then removed. Special attention should be made to the left atrial cuffs. These may be taken as two discrete cuffs or one single. The right-sided cuff can be compromised, and dissecting Sondergaard’s groove prior to recovery can help prevent this problem.

Once the heart is out, we proceed with retrograde perfusion of the donor lungs via the pulmonary vein orifices (500 cm³ in each). Low-potassium dextran has emerged as the most common and currently best preservation solution. This is particularly true for high-risk lung transplant recipients.¹³ The maximal acceptable ischemic time for lungs is between 6 and 8 hours.

The dissection then proceeds outside the pericardium and anterior or ventral to the esophagus. The left and right pleura are then incised along the esophagus as far cephalad as possible. On the right, the azygous vein is transected, and on the left, the aorta is transected. The airway is then isolated between the aorta and SVC and tissue cleared laterally. The final attachments are usually at the level of the carina, and the airway is stapled with a modest level of inflation. We have never found it necessary to take the esophagus with the bloc but some centers work in this plane to prevent injury to the allograft.

The lungs are then inspected for damage and packed in iced saline and preservation solution. In the case of single-lung transplantation, the bloc should be divided prior to packaging.

Single Versus Bilateral Lung Transplant

Bilateral lung transplant is necessary in suppurative lung diseases and in pulmonary hypertension. Single-lung transplantation can be used in patients with interstitial or fibrotic lung disease and emphysema. However, there is some evidence that bilateral lung transplant may have advantages in COPD and IPF. Although patients with IPF have similar outcomes with single or bilateral lungs, high-risk IPF patients may benefit from bilateral lung transplant.^14–16 For COPD, there is a modest survival and potential immunologic advantage. Certainly, bilateral lung transplant in emphysema eliminates complications of the native lung including hyperinflation, pneumothorax, differential compliance, and long-term risk of malignancy.

Heart–Lung Transplant

Patients with end-stage heart and lung disease are candidates for combined heart–lung transplant. Although primary or secondary pulmonary hypertension is no longer an exclusive indication for heart–lung transplant, patients with biventricular failure or unreconstructable heart disease are reasonable candidates. Occasionally, cystic fibrosis, primary pulmonary hypertension, and sarcoid patients will have biventricular failure.

Bilateral Sequential Lung Transplantation

After the induction of anesthesia, the recipient is intubated with a double-lumen endotracheal tube whenever possible. Even when cardiopulmonary bypass (CPB) is planned, double-lumen tubes allow for flexibility in dissection and reperfusion management. Pulmonary artery catheters are routinely as well as radial and femoral arterial lines. The femoral arterial line allows more consistent blood pressure measurement. It also allows access to place intra-aortic balloon pumps and extracorporeal circulation cannulae. The arms are placed over the head in arm stirrups (Fig. 11-2). Bilateral anterolateral thoractomies are performed through the fourth or fifth interspace and across the sternum (Fig. 11-3). Some centers have used sternal-sparing techniques or bilateral posterolateral thoractomies. Median sternotomy may also be used; however, access to pleural adhesions may be limited.

Once the retrosternal mediastinal adhesions are cleared cephalad and caudad, the intercostals muscles are incised with cautery generously. Two retractors are placed and the exposure is excellent. Attention is turned to the right lung first to isolate the inferior and superior veins, and then the pulmonary artery. The left lung is similarly dissected. In the presence of dense adhesions or severe bleeding, an intrapericardial dissection may allow safer isolation, and an extrapleural dissection may cause less bleeding. When the donor lungs have arrived, the less perfused lung (based on preoperative ventilation/perfusion scan) is removed first using vascular staplers. The bronchus is finally stapled. The hilar structures are further dissected into the pericardium to allow for maximal length and minimal cardiac manipulation.

The donor lung is placed in the chest, wrapped in an iced sponge. The airway is then anastomosed with running prolene or PDS. This may be done with a telescoping or end-to-end technique. The membranous trachea may be approximated with a continuous suture and the cartilaginous with an interrupted technique. We use a simple running, end-to-end technique with satisfactory results.