Predictors of Outcomes After Thoracic Surgery in Orthotopic Liver Transplant Recipients With Pleural Disease

Implications of Pleural Fluid Composition in Persistent Pleural Effusion following Orthotopic Liver Transplant

Persistent pleural effusions (PPEf) represent a known complication of orthotopic liver transplant (OLT). However, their clinical relevance is not well described. We evaluated the clinical, biochemical, and cellular characteristics of post-OLT PPEf and assessed their relationship with longitudinal outcomes. We performed a retrospective cohort study of OLT recipients between 2006 and 2015. Included patients had post-OLT PPEf, defined by effusion persisting >30 days after OLT and available pleural fluid analysis. PPEf were classified as transudates or exudates (Exud^Light) by Light's criteria. Exudates were subclassified as those with elevated lactate dehydrogenase (Exud^LDH) or elevated protein (Exud^Prot). Cellular composition was classified as neutrophil- or lymphocyte-predominant. Of 1602 OLT patients, 124 (7.7%) had PPEf, of which 90.2% were Exud^Light. Compared to all OLT recipients, PPEf patients had lower two-year survival (HR 1.63; p = 0.002). Among PPEf patients, one-year mortality was associated with pleural fluid RBC count (p = 0.03). While Exud^Light and Exud^Prot showed no association with outcomes, Exud^LDH were associated with increased ventilator dependence (p = 0.03) and postoperative length of stay (p = 0.03). Neutrophil-predominant effusions were associated with increased postoperative ventilator dependence (p = 0.03), vasopressor dependence (p = 0.02), and surgical pleural intervention (p = 0.02). In summary, post-OLT PPEf were associated with increased mortality. Ninety percent of these effusions were exudates by Light's criteria. Defining exudates using LDH only and incorporating cellular analysis, including neutrophils and RBCs, was useful in predicting morbidity.

Surgical chest complications after liver transplantation

Liver transplantation is a major abdominal operation and the intimate anatomic relation of the liver with the right hemidiaphragm predisposes the patient to various manifestations in the chest cavity. Furthermore, chronic liver disease affects pulmonary function before and after liver transplantation resulting in a considerable percentage of patients presenting with morbidity related to chest complications. This review aims to identify the potential chest complications of surgical interest during or after liver transplantation. Complications of surgical interest are defined as those conditions that necessitate an invasive procedure (such as thoracocentesis or a chest tube placement) in the chest or a surgical intervention performed by a thoracic surgeon. These complications will be classified as perioperative and postoperative; the latter will be categorized as early and late. Although thoracocentesis or a chest tube placement is usually sufficient when invasive measures are deemed necessary, in some patients, thoracic surgical interventions are warranted. A high index of suspicion is needed to recognize and treat these conditions promptly. A close collaboration between abdominal surgeons, intensive care unit physicians and thoracic surgeons is of paramount importance.

Postoperative Trapped Lung After Orthotopic Liver Transplantation is a Predictor of Increased Mortality

Pleural effusions are a common complication of orthotopic liver transplantation (OLT), and chronic post-OLT pleural effusions have been associated with worse outcomes. Furthermore, “trapped lung” (TL), defined as a restrictive fibrous visceral pleural peel preventing lung re-expansion, may have prognostic significance. We performed a retrospective analysis of adult OLT recipients over a 9-year period at UCLA Medical Center. Post-OLT patients with persistent pleural effusions, defined by the presence of pleural fluid requiring drainage one to 12 months after OLT, were included for analysis. Outcomes for patients with and without TL were compared using univariate and multivariate analysis. Of the 1722 patients who underwent OLT, 117 (7%) patients met our criteria for persistent postoperative pleural effusion, and the incidence of TL was 21.4% (25/117). Compared to patients without TL, those with TL required more surgical pleural procedures (OR 59.8, 95%CI 19.7–181.4, p < 0.001), spent more days in the hospital (IRR 1.56, 95%CI 1.09–2.23, p = 0.015), and had a higher risk of mortality (HR 2.47, 95%CI 1.59–3.82, p < 0.001) following transplant. In sum, we found that post-OLT TL was associated with higher morbidity, mortality, and healthcare utilization. Future prospective investigation is warranted to further clarify the risk factors for developing postoperative pleural effusions and TL.

Preoperative Trapped Lung Is Associated With Increased Mortality After Orthotopic Liver Transplantation

INTRODUCTION

Trapped lung, characterized by atelectatic lung unable to reexpand and fill the thoracic cavity due to a restricting fibrous visceral pleural peel, is occasionally seen in patients with end-stage liver disease complicated by hepatic hydrothorax. Limited data suggest that trapped lung prior to orthotopic liver transplantation may be associated with poor outcomes.

RESEARCH QUESTION

What is the clinical significance of trapped lung in patients receiving orthotopic liver transplantation?

DESIGN

We performed a retrospective analysis of patients who underwent liver transplantation over an 8-year period. Baseline clinical characteristics and postoperative outcomes of adult patients with trapped lung were analyzed and compared to the overall cohort of liver transplant recipients and controls matched 3:1 based on age, sex, Model for End-Stage Liver Disease (MELD) score, and presence of pleural effusion.

RESULTS

Of the 1193 patients who underwent liver transplantation, we identified 20 patients (1.68%) with trapped lung. The probability of 1 and 2-year survival were 75.0% and 57.1%, compared to 85.6% and 80.4% (p = 0.02) in all liver transplant recipients and 87.9% and 81.1% (p = 0.03) in matched controls respectively. Patients with trapped lung had a longer hospital length of stay compared to the total liver transplant population (geometric mean 54.9 ± 8.4 vs. 27.2 ± 0.7 days, p ≤ 0.001), when adjusted for age and MELD score.

DISCUSSION

Patients with trapped prior to orthotopic liver transplantation have increased probability of mortality as well as increased health care utilization. This is a small retrospective analysis, and further prospective investigation is warranted.

Pulmonary Complications of Portal Hypertension

The most common pulmonary complications of chronic liver disease are hepatic hydrothorax, hepatopulmonary syndrome, and portopulmonary hypertension. Hepatic hydrothorax is a transudative pleural effusion in a patient with cirrhosis and no evidence of underlying cardiopulmonary disease. Hepatic hydrothorax develops owing to the movement of ascitic fluid into the pleural space. Hepatopulmonary syndrome and portopulmonary hypertension are pathologically linked by the presence of portal hypertension; however, their pathophysiologic mechanisms are significantly different. Hepatopulmonary syndrome is characterized by low pulmonary vascular resistance secondary to intrapulmonary vascular dilatations and hypoxemia; portopulmonary hypertension features elevated pulmonary vascular resistance and constriction/obstruction within the pulmonary vasculature.