Recipients of lung transplantation are surviving longer. As a consequence, complications secondary to the procedure (surgical) or resulting from mandatory lifelong immunosuppression (medical) are becoming increasingly evident. These events can lead to significant morbidity and potential mortality if not managed appropriately and in a timely fashion. This chapter focuses on the common surgical complications of lung transplantation.
Transplant operations of all types require at minimum two separate surgical procedures: retrieval of the organ from the donor and implantation of the organ into the recipient. Thus technical complications can occur during any phase of either operation. Pitfalls of donor procurement include inadequate harvest of the atrial cuff or iatrogenic injury to the pulmonary artery, pulmonary veins, bronchus, and lung parenchyma. Complications secondary to lung implantation include phrenic nerve injury, hemorrhage, and pulmonary hypertension/hypoxemia.
Donor procurement is always performed on an emergent basis. Consequently, despite the best efforts of both the heart and lung procurement teams to equitably divide the left atrial cuff and preserve the pulmonary vein orifices, the donor lungs occasionally arrive at the recipient OR in less than optimal condition, with either insufficient left atrial cuff or lacerated pulmonary vein orifices (in particular, the right inferior pulmonary vein). These injuries usually occur as a result of poor visibility or undue haste during division of the left atrial cuff. Laceration of the pulmonary vein orifice is repaired simply by dividing the pericardium overlying the vein and exposing the vessel to the point where it disappears into the lung parenchyma. Small branches of the vein also may require repair if the vein orifice was entered during procurement. These branches should be identified and oversewn to prevent troublesome bleeding after reperfusion.
Casula et al.1 have described a useful technique for augmenting the pulmonary veins with donor pericardium when the left atrial cuff is found to be inadequate. This method can be used to create a cuff even when the superior and inferior pulmonary veins are completely separated. A running 5-0 polypropylene suture is placed around each vein orifice to tack the intima to the pericardium, thereby creating a “neoatrial cuff.” Scissors are used to trim the newly created pericardial cuff and separate it from the other hilar structures. This pericardial cuff substitutes for donor atrium in the atrial anastomosis. Alternatively, donor superior vena cava or redundant donor pulmonary artery can be used for the reconstruction if there is inadequate pericardial tissue.
The bifurcation of the pulmonary artery always should be taken with the lung graft at the time of procurement. Even when a heart transplant is planned from the same donor, dividing the pulmonary artery at the distal extent of the main trunk proximal to the bifurcation leaves a sufficient and safe length of artery for the heart transplant. Common sites of pulmonary artery injury during donor procurement include the right pulmonary artery as it travels behind the aorta or posterior to the superior vena cava. Because the right pulmonary artery is substantially longer than the left, when injury to this vessel occurs behind the aorta, it rarely requires repair, and the artery simply can be trimmed distal to the laceration. However, when the first branch of the right pulmonary artery is lacerated deep to the superior vena cava, it must be repaired. Usually, the laceration can be repaired with suture, but when reconstruction of the truncus anterior is required, a patch or complete reimplantation may be needed to prevent loss of diameter in the repaired vessel. This sort of repair can be performed with a segment of donor vena cava, azygos vein, or redundant donor pulmonary artery.
Traumatic injury to the lung parenchyma or main bronchi during procurement is rarely significant. The worst result is a prolonged air leak after implantation, which eventually resolves. Special care should be taken when the implantation is performed with cardiopulmonary bypass because even small parenchymal injuries may lead to endobronchial bleeding under circumstances of profound anticoagulation for bypass.
On the other hand, atraumatic injury to the lung parenchyma in the form of inadequate cooling and preservation can have grave consequences. For example, technical problems may occur in the delivery of the flush solution used to cool and preserve the lungs during extracorporeal ischemia. Inadequate flushing of the lungs during procurement can lead to profound ischemia–reperfusion injury and poor initial graft function after implantation. We experienced an extreme example of ischemia–reperfusion injury in a bilateral lung transplant performed in a patient with cystic fibrosis. On a routine postoperative ventilation/perfusion scan, no flow was observed perfusing the left lung (Fig. 112-1). A pulmonary arteriogram demonstrated a patent anastomosis without evidence of technical flaws to account for the absent blood flow (Fig. 112-2). Reexploration revealed an edematous ischemic lung with severe reperfusion injury that necessitated removal of the graft. Analysis of this case revealed that the flush of preservative solution had been preferentially and exclusively directed down the right pulmonary artery, thus exposing the left lung to a no-reflow phenomenon as a consequence of severe ischemic injury. Our procurement protocol has been developed to minimize this occurrence. When the pulmonary artery cannula used to administer the lung preservation solution is inserted in proximity to the pulmonary artery bifurcation (as required when the heart is also suitable for procurement) and also directed towards the bifurcation, the tip may inadvertently slip into either the left or right pulmonary artery resulting in asymmetric perfusion. We have found that inserting the pulmonary artery cannula near the bifurcation with the tip directed towards the heart provides an adequate and uniform distribution to the bilateral lungs and avoids differential flow. In addition, we look for equal “blanching” of both lungs during the administration of the preservation solution. Finally, after cardiac excision, the remaining perfusion solution is infused into each individual pulmonary vein orifice as a retrograde flush.2
Figure 112-2
Pulmonary artery angiogram performed after postoperative perfusion scan showed no perfusion to newly implanted left lung. A patent left-sided anastomosis is seen without evidence of technical flaws to account for the absent blood flow in the lung. It was concluded in this case that the no-reflow phenomenon secondary to severe ischemic injury was the likely cause for lack of blood flow to the left graft.
Dense adhesions present at the time of explantation can increase the risk of bleeding as well as the risk of injury to the phrenic and left recurrent nerves. These adhesions are most common in patients with septic lung diseases (e.g., cystic fibrosis and bronchiectasis) and patients who have had previous thoracic surgery. While once rare, it is increasingly common to consider reoperative lung transplantation and the adhesions can be formidable. Particularly dense adhesions have been seen in emphysema patients who have undergone previous lung-volume–reduction surgery. In a multicenter experience of 35 lung transplant patients who had previously undergone lung-volume–reduction surgery, phrenic nerve injury was recorded in two patients (5.7%).3 We have noted that the phrenic nerve often adheres to the lung-volume–reduction surgery staple line, making dissection of the phrenic nerve both tedious and dangerous. To avoid injury to the phrenic nerve in these patients, we leave the staple line, along with a small amount of residual lung tissue, attached to the phrenic nerve and use a lung stapler to divide the densely attached tissue. Electrocautery to take down mediastinal adhesions should be avoided because it greatly increases the risk of phrenic nerve injury.
If one of the phrenic nerves is injured, little can be done to remedy the situation acutely. The consequences are not as dire with a bilateral transplant, which mitigates the impact of unilateral phrenic injury. The redundant lung ensures an overall acceptable outcome, and consequently, this complication is often underreported. When the phrenic nerve is injured during a unilateral transplant, the benefit of the transplant is greatly diminished. It has been exceedingly rare in our experience or in the reported literature for a patient to require diaphragmatic plication after lung transplantation.
Hemorrhage was once a common complication after lung transplantation. Indeed, in the early experience of some programs undertaking heart–lung and en bloc double-lung transplants, approximately 25% of patients required reoperation for postoperative bleeding. However, improved technique and perioperative care have reduced the incidence of life-threatening hemorrhage. While the use of strategic incisions (posterolateral thoracotomy for single-lung transplantation and the clamshell and sternal-sparing clamshell incisions for bilateral lung replacement) has improved surgical exposure and contributed to the prevention of hemorrhage, the availability of a variety of hemostatic agents has played an important role in the control of hemorrhage.4,5 The use of aprotinin has largely been abandoned due to concerns about toxicity. In contrast, the role of factor concentrates – such as recombinant Factor VII and activated prothrombin complex concentrates – is not as clear. Although small case studies suggest that the use of recombinant Factor VII in lung transplantation is associated with reduced blood loss and decreased need for blood transfusions without the development of thromboembolic complications, further studies are needed to establish the safety and efficacy of such products.6 At our institution, we consider using factor concentrates when the following occur: (1) bleeding exceeds 500 to 1000 mL/h, (2) hemorrhage is diffuse and cannot be surgically addressed, and (3) bleeding is refractory to pharmacologic agents (DDAVP, aminocaproic acid) and aggressive transfusion of hemostatic components (platelets, fresh frozen plasma, cryoprecipitate).7
Persistent pulmonary hypertension and unexplained hypoxemia after lung implantation can occur as a result of stenosis at the pulmonary artery anastomosis. A nuclear perfusion scan that demonstrates less than anticipated flow to a single-lung graft or unequal distribution of flow in a bilateral lung recipient can suggest this problem. Occasionally, transesophageal echocardiography can visualize a stenotic vascular anastomosis. Contrast angiography should be performed in any patient for whom there is such a concern. At the time of angiography, the pressure gradient across the pulmonary artery anastomosis should be determined. A gradient of 15 to 20 mm Hg is commonly encountered, especially in single-lung recipients, in whom most of the cardiac output may be directed to the transplanted lung, or in bilateral recipients, who have a high cardiac output. The need for anastomotic revision is dictated by the clinical situation, but this intervention is quite uncommon. Treatment options include observation, reoperation, or angioplasty with or without stent placement if surgical revision is considered too high a risk.8 Dramatic reduction in flow should not be accepted because the donor bronchus is totally dependent on pulmonary arterial collateral flow.
Compromised flow across the atrial anastomosis also can occur as a result of unsatisfactory anastomotic technique. Impaired venous outflow results in elevated venous pressure and ipsilateral pulmonary edema. Pulmonary artery pressures remain unexpectedly high in this situation, and flow through the graft is less than expected. Transesophageal echocardiography is often used to assess patency and flow through the atrial anastomoses. Contrast studies may be helpful in demonstrating a reduced level of flow through the anastomoses. Open exploration occasionally is necessary to confirm the diagnosis and conduct appropriate repair.
The bilateral transsternal thoracotomy provides excellent exposure to the hila and pleural spaces, but problems have been reported with poor sternal healing. Brown and colleagues9 report an institutional prevalence of 36% for sternal disruption in transverse bilateral thoracosternotomy for lung transplantation, and they cited disruption rates of 20% to 60% at centers worldwide. Lung transplant recipients are particularly prone to poor sternal healing (Fig. 112-3) owing to their debilitated state and the routine use of postoperative corticosteroids.4 Sternal override is a common complication that results from a tendency of the distal sternum to angulate and displace anteriorly, a translational movement that is not prevented by the sternal wires. The addition of coaxial stabilization, either with long, thin Kirschner wires or with short, stout Steinmann pins placed within the cancellous bone of the sternum, reduces the incidence of sternal override and translational movement at the bony closure. However, these wires have a tendency to migrate, causing other problems (Fig. 112-4). We have removed numerous wires that have migrated from the sternum to various locations in the body. Such retrievals require interventions of various complexity, ranging from the administration of local anesthetic to liberate a wire that has eroded through the anterior chest wall to a laparoscopic procedure under general anesthesia to remove a Kirschner wire from the pouch of Douglas. Case reports suggest that the use of longitudinal titanium plates for sternal fixation may provide improved results for high risk patients or those requiring reclosure after sternal dehiscence. The Synthes Titanium Sternal Fixation System (Synthes, Westchester, PA) involves titanium plates that can be molded to the contour of the sternum, and includes a drill/titanium screw gauging system to ensure that the screws pierce both the anterior and posterior tables of the sternum, without protruding beyond the posterior border.9 As a prophylactic maneuver, the procedure does add time and cost to the operation, and further studies are needed to define which patients would benefit from such precautions.10,11
Figure 112-4
Chest radiograph of a lung transplant recipient who had required a clamshell incision for adequate exposure. He presented several months later with a Steinmann pin eroding through his sternum and projecting anteriorly toward his skin. The area was prepped, and the Steinmann pin was simply removed with a small cutdown incision.
Deep sternal wound infection is an additional serious complication of transverse sternotomy. We have encountered this problem in several patients, and it has required operative and bedside wound debridement with additional antibiotics and a prolonged hospital stay. The estimated prevalence for all sternal closure complications in our historical control group is 34%. With this in mind, we routinely avoid sternal division and have found that adequate exposure in many circumstances can be provided by bilateral anterior thoracotomies alone. Additionally, in rare selected patients, we also advocate modified approaches such as a combined left posterolateral and right anterior thoracotomy to optimize the left hilar exposure without the need for sternal division or separate positioning, preparation, or draping. We have found that the use of a cardiac positioning device designed for off-pump cardiac stabilization (apical suction cup) can be useful to expose the left hilum and avoid sternal division and cardiopulmonary bypass.
Primary graft dysfunction is one of the most important complications of lung transplantation and represents a common cause of early mortality and prolonged ICU stay. The frequency of primary graft dysfunction at our institution is 23%.12 The impact of primary graft dysfunction is enormous. Patients experiencing initial graft dysfunction at our institution had a mortality of 28.8% compared with 4.2% in patients without the condition.
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