Hepatopulmonary syndrome: what are we learning from interventional radiology, liver transplantation, and other disorders?

Pulmonary Hypertension that Developed During Treatment for Hepatopulmonary Syndrome and Pulmonary Arteriovenous Malformation

Hepatopulmonary syndrome (HPS) and pulmonary arteriovenous malformation (PAVM) are hypoxemic diseases caused by right-to-left shunting but are rarely concomitant with pulmonary hypertension (PH). A 66-year-old woman with chronic hepatitis C was scheduled to undergo liver transplantation. She was referred to our department for hypoxia and an abnormal shadow in the right lung found on a preoperative examination. She was diagnosed with HPS and a PAVM in the right middle lobe. After liver transplantation, PH temporarily developed, but the pulmonary arterial pressure normalized after coil embolization. Combined HPS and PAVM may cause unique changes in pulmonary hemodynamics during treatment.

Cryptogenic Cirrhosis and Hepatopulmonary Syndrome in a Boy with Hepatic Hemangioma in Botswana: A Case Report and Review of the Literature

Hepatic hemangiomas are considered to be the most common benign tumors of the liver. They are often found incidentally while investigating for other causes of liver disease. Hemangiomas that are less than 10 cm are not expected to cause any problems. Typically, they do not enlarge and, apart from regular follow-up, no definitive treatment is indicated. This is a posthumous case report of a male child with a medium-sized hemangioma from infancy, complicated by cryptogenic cirrhosis and hepatopulmonary syndrome. It demonstrates the challenges of managing a child with such complicated conditions in a resource-limited setting.

Hepatopulmonary syndrome: update on recent advances in pathophysiology, investigation, and treatment

Hepatopulmonary syndrome (HPS) is an important cause of dyspnea and hypoxia in the setting of liver disease, occurring in 10-30% of patients with cirrhosis. It is due to vasodilation and angiogenesis in the pulmonary vascular bed, which leads to ventilation-perfusion mismatching, diffusion limitation to oxygen exchange, and arteriovenous shunting. There is evidence, primarily from animal studies, that vasodilation is mediated by a number of endogenous vasoactive molecules, including endothelin-1 and nitric oxide (NO). In experimental HPS, liver injury stimulates release of endothelin-1 and results in increased expression of ET(B) receptors on pulmonary endothelial cells, leading to upregulation of endothelial NO synthase (eNOS) and subsequent increased production of NO, which causes vasodilation. In addition, increased phagocytosis of bacterial endotoxin in the lung not only promotes stimulation of inducible NO synthase, which increases NO production, but also contributes to intrapulmonary accumulation of monocytes, which may stimulate angiogenesis via vascular endothelial growth factor pathway. Despite these insights into the pathogenesis of experimental HPS, there is no established medical therapy, and liver transplantation remains the main treatment for symptomatic HPS, although selected patients may benefit from other surgical or radiological interventions. In this review, we focus on recent advances in our understanding of the pathophysiology of HPS, and discuss current approaches to the investigation and treatment of this condition.

Transjugular intrahepatic portosystemic shunt

The transjugular intrahepatic portosystemic shunt (TIPS) is an interventional treatment resulting in decompression of the portal system by creation of a side-to-side portosystemic anastomosis. Since its introduction 16 years ago, more than 1,000 publications have appeared demonstrating broad acceptance and increasing clinical use. This review summarizes our present knowledge about technical aspects and complications, follow-up of patients and indications. A technical success rate near 100% and a low occurrence of complications clearly depend on the skills of the operator. The follow-up of the TIPS patient has to assess shunt patency, liver function, hepatic encephalopathy and the possible development of hepatocellular carcinoma. Shunt patency can best be monitored by duplex sonography and can avoid routine radiological revision. Short-term patency may be improved by anticoagulation, while such a treatment does not influence long-term patency. Stent grafts covered with expanded polytetrafluoroethylene show promising long-term patency comparable with that of surgical shunts. With respect to the indications of TIPS, much is known about treatment of variceal bleeding and refractory ascites. The thirteen randomized studies that are available to date show that survival is comparable in patients receiving TIPS or endoscopic treatment for acute or recurrent variceal bleeding. Another group comprises patients with refractory ascites and related complications, such as hepatorenal syndrome and hepatic hydrothorax. It has been demonstrated that TIPS improves these complications. Five randomized studies comparing TIPS with paracentesis and one study comparing TIPS with the peritoneo-venous shunt showed good response of ascites but controversial results on survival. In addition, TIPS has been successfully applied to patients with Budd-Chiari syndrome, portal vein thrombosis, before liver transplantation, and for the treatment of ectopic variceal bleeding.

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

RACIONAL: A síndrome hepatopulmonar é caracterizada por tríade clínica que consiste em: 1) doença hepática e/ou hipertensão portal, 2) dilatações vasculares intra-pulmonares, e 3) anormalidades da oxigenação arterial (pressão parcial de oxigênio <70 mm Hg ou gradiente alvéolo-arterial de oxigênio >20 mm Hg). Sua freqüência varia de acordo com os métodos diagnósticos utilizados. OBJETIVOS: Fazer revisão da literatura sobre patogenia, diagnóstico e tratamento da síndrome hepatopulmonar. MÉTODOS: Levantamento no MEDLINE das publicações nacionais e internacionais mais relevantes sobre a síndrome hepatopulmonar. RESULTADOS: A prevalência da síndrome hepatopulmonar varia de 4% a 17,5%, a depender dos critérios diagnósticos utilizados. A doença hepática associada mais comum é a cirrose. O gradiente alvéolo-arterial de oxigênio parece ser o melhor parâmetro para avaliação das anormalidades da oxigenação arterial. Em relação à detecção das dilatações vasculares intra-pulmonares, a ecocardiografia com contraste é o método de escolha, pois é de fácil realização e pode diferenciar as comunicações intra-pulmonares das intra-cardíacas. No tratamento da síndrome hepatopulmonar, poucos relatos bem sucedidos puderam ser reproduzidos e confirmados utilizando terapia farmacológica e/ou radiologia intervencionista. Atualmente, o transplante de fígado é considerado a principal opção terapêutica desses pacientes, com resultados animadores. CONCLUSÕES: A síndrome hepatopulmonar é uma enfermidade freqüente. Exames gasométricos são necessários para o seu diagnóstico. O transplante de fígado é o tratamento de escolha para os portadores da síndrome.

The first decade of the transjugular intrahepatic portosystemic shunt (TIPS): state of the art

The transjugular intrahepatic portosystemic shunt (TIPS) is an interventional treatment resulting in decompression of the portal system by creation of a side-to-side portosystemic anastomosis. Since its introduction 10 years ago, more than 500 publications have appeared demonstrating rapid acceptance and increasing clinical use. This review summarizes the present knowledge of technical aspects and complications, follow-up of patients, and indications. With respect to the technique, the TIPS procedure is probably one of the most difficult interventions and, therefore, technical success and complications clearly depend on the skills of the operator. Thus, the number and kind of complications reported in this review do not necessarily relate to the procedural complications of an experienced center. The follow-up of the TIPS patient has to assess shunt patency, liver function and hepatic encephalopathy. Shunt patency can best be monitored by duplex-sonography. Routine radiological revision seems not to be helpful and does not improve results, i.e., rebleeding and survival. Short term patency may be improved by anticoagulation, while such a treatment does not influence long-term patency. With respect to the indications of TIPS, much is known about treatment of variceal bleeding. The nine randomized studies that are available to date show that survival is comparable between patients receiving TIPS or endoscopic treatment. The second group of patients is the group with refractory ascites and related complications, such as hepatorenal syndrome and hepatic hydrothorax. It has been demonstrated that TIPS improves these complications, but randomized studies are still lacking. In addition, TIPS has been applied successfully to patients with Budd-Chiari syndrome, portal vein thrombosis, before liver transplantation, and for the treatment of ectopic portal hypertensive bleeding.

Early liver transplantation is crucial in children with liver disease and pulmonary artery hypertension

BACKGROUND/AIMS

Early liver transplantation is crucial in children with liver disease and pulmonary artery hypertension. Some severe pulmonary vascular anomalies associated with portal hypertension disappear after isolated liver transplantation. Evolution of pulmonary artery hypertension due to plexogenic arteriopathy is controversial, as this association is still considered a contraindication to isolated liver transplantation. Outcome of pulmonary hypertension after isolated liver transplantation is reported in three patients with portal hypertension.

METHODS

After echocardiographic diagnosis, the patients had a complete hemodynamic exploration, and two had a lung biopsy. After liver transplantation, the survivors had echocardiographic follow up and a second hemodynamic exploration.

RESULTS

In two children, pulmonary pressures and resistances returned to near-normal values 1 and 6 years after successful isolated liver transplantation. The third patient, with the most severe arteriopathy, had to wait 1 year for a donor, and the attempted transplantation was complicated by ventricular tachycardia; death occurred 2 days after surgery.

CONCLUSIONS

Liver transplantation can reverse pulmonary artery hypertension due to high pulmonary resistances complicating liver disease with portal hypertension, provided it is carried out at an early stage. Early detection of pulmonary hypertension by systematic echocardiography may thus be crucial in these children with portal hypertension.

Indications for and timing of liver transplantation

The tremendous success of OLT as a highly effective treatment for patients with end-stage liver disease has resulted in a rapid increase in the number of candidates for the procedure. Refinements in organ preservation, improvements in surgical technique and immunosuppression, and better postoperative management have contributed to improved survival rates. The discrepancy between the paucity of organs and the increasing numbers of potential recipients will continue to worsen until there are extraordinary breakthroughs in providing alternatives to human whole-organ livers, such as xenografts or cultured hepatocyte infusions. For now, the vast majority of patients with life-threatening liver disease are not likely to receive a liver graft. Thus, the issues of patient selection and timing of OLT have become even more relevant. Prompt referral to a transplant center is not only in the patient's best interest, but also it has been shown to be cost-effective. Over the last 30 years, it has become clear that hepatic malignancy, initially a common reason for OLT, should be an indication for transplantation only in highly selected individuals. The role of adjuvant chemotherapy needs to be defined, and proven treatment alternatives need to be developed. New antiviral agents may enable a large group of patients with chronic hepatitis B to be successfully transplanted, placing even greater demands on the already limited supply of donor livers. Hepatitis B appears to be species specific, and it is conceivable that xenotransplantation from a nonsusceptible donor species may confer protection to HBV reinfection, eliminating the problems of an inadequate donor supply. Until novel approaches, including xenotransplantation, gene therapy, or replacement of hepatic function by cultured hepatocyte infusions, become a widespread reality, future allocation policies may highlight outcome as well as urgency as a fundamental variable to determine if transplantation is reasonable. Survival rates have been shown to fall with advancing levels of urgency, resulting in a conflict between equity and efficacy in organ allocation. As waiting lists for liver transplantation continue to grow, it is becoming increasingly apparent that patients must be referred to a transplant center earlier in the course of liver disease.