Abstract
Unilateral paralysis of the right hemidiaphragm after liver transplantation has a reported incidence of 30% to 40%.1, 2 The mechanism of injury is most often a crush injury to the phrenic nerve due to the application of a suprahepatic inferior vena cava clamp.1, 3 Most patients who suffer diaphragmatic paralysis at the time of transplantation never develop symptoms. Eventration of the right hemidiaphragm after liver transplantation causing right atrial compression and hemodynamic changes, to our knowledge, has not previously been reported. A 55-year-old man underwent combined liver and kidney transplantation for symptomatic polycystic liver and kidney disease. Liver transplantation was performed in the standard fashion with the piggyback technique, and the kidney was placed in the right iliac fossa at the same time. The explanted liver weighed 7.5 kg. The initial postoperative recovery was unremarkable aside from a slightly longer than usual time to extubation. He was discharged on postoperative day 14 with a normal laboratory workup and no complaints. He re-presented 10 days later and complained of shortness of breath that was relieved in the sitting position. He was worked up for a pulmonary embolism and myocardial infarction but was found to be negative for both. Over the course of his admission for the evaluation of these complaints, he experienced multiple episodes of supraventricular tachycardia (SVT) that required adenosine for cardioversion. A computed tomography scan of his chest revealed extrinsic compression of the right atrium by the liver (Fig. 1). A transthoracic echocardiogram confirmed the computed tomography finding and demonstrated mildly reduced flow in the right atrium while he was supine. Right heart catheterization was also performed and confirmed that the right atrium was significantly narrowed by extrinsic compression. Pulmonary function testing was consistent with a restrictive pattern of disease, and the sniff test confirmed diminished movement of the right hemidiaphragm. The imaging findings along with the patient’s complaints and his episodic SVT suggested a diagnosis of extrinsic compression of the right atrium by the liver as a result of diaphragmatic eventration. The patient subsequently underwent plication of the right hemidiaphragm through a right thoracotomy performed through the seventh intercostal space (Fig. 2). The procedure was performed in the supine position after attempts at left lateral decubitus induced SVT. Adenosine was again required to convert the patient to a normal sinus rhythm. Intraoperative transesophageal echocardiography was used to evaluate the patient’s heart in this dynamic period. All images were captured in the supine position because of the previously described instability. Figure 3 demonstrates the compression of the right atrium at the outset of the case and the hepatic tissue visualized in the thoracic cavity immediately adjacent to the compressed right atrium. The patient recovered well from the thoracotomy and had no subsequent episodes of SVT or subjective reports of significant shortness of breath. Follow-up transthoracic echocardiography demonstrated a normal right atrium size and no evidence of thoracic invasion of the liver. Diaphragmatic paralysis occurs in 30% to 40% of patients after liver transplantation. This is usually caused by the application of a suprahepatic caval clamp and the resulting crush injury to the phrenic nerve. Excessive electrocautery on the diaphragm while the liver is being separated from the diaphragm is another potential etiology.1, 3 Diaphragmatic eventration can also result from excessive chronic stretching of the diaphragm.4 In our patient, the cardiac irritability (SVT) was the result of his liver being displaced into the right hemithorax and compressing the right side of the heart. This was due to the extensive stretching of the right hemidiaphragm from his large polycystic native liver and its pliability; this allowed the new, relatively small graft to move into the thoracic space, usually with changes in position. Compromise of the phrenic nerve due to the stretching itself, the application of clamps during surgery, or indeed both could also have contributed by ensuring poor functioning of an already stretched and thin hemidiaphragm. McAlister et al.1 found phrenic nerve paralysis in 79% and right diaphragmatic paralysis in 38% of patients after liver transplantation. They also found that the left phrenic nerve was intact in all patients. None of the patients in their review were symptomatic. Smyrniotis et al.5 reported a case series of infants with diaphragmatic paralysis after liver transplantation who required prolonged ventilation and were treated with diaphragmatic plication. Diaphragmatic eventration or paralysis causing right atrial compression has rarely been described. Tayyareci et al.6 reported a case of asymptomatic right atrial compression seen incidentally on an echocardiogram. Oh et al.7 reported a case of central eventration causing left ventricular compression and arrhythmias. There are case reports in the literature describing enlarged polycystic kidneys causing right atrial compression and hemodynamic compromise.8, 9 Diaphragmatic paralysis is diagnosed by an elevated hemidiaphragm on a chest X-ray. The sniff test under fluoroscopy or ultrasound can confirm the diagnosis. Pulmonary function tests will show a restrictive pattern.10 Diaphragmatic plication abolishes the paradoxical movement of the diaphragm and increases lung volumes. Although thoracoscopic and abdominal approaches have been used with acceptable results, in our case, we used the standard right thoracotomy approach because it allowed us to visualize the right atrium and manually relieve the hepatic compression if the patient became unstable. With the help of intraoperative transesophageal echocardiography, we were able to confirm that the pressure on the right atrium was relieved after the plication. Vinayak Rohan, M.D.1 Eric Bolin, M.D.2 William Hand, M.D.2 William David Stoll, M.D.2 John McGillicuddy, M.D.1 Kenneth D. Chavin, M.D., Ph.D.1 1Division of Transplant Surgery, Department of Surgery 2Department of Anesthesia, Medical University of South Carolina, Charleston, SC