Pulmonary Arterial Hypertension in Portal Hypertension

Pediatric Pulmonary Hypertension: Guidelines From the American Heart Association and American Thoracic Society

Pulmonary hypertension is associated with diverse cardiac, pulmonary, and systemic diseases in neonates, infants, and older children and contributes to significant morbidity and mortality. However, current approaches to caring for pediatric patients with pulmonary hypertension have been limited by the lack of consensus guidelines from experts in the field. In a joint effort from the American Heart Association and American Thoracic Society, a panel of experienced clinicians and clinician-scientists was assembled to review the current literature and to make recommendations on the diagnosis, evaluation, and treatment of pediatric pulmonary hypertension. This publication presents the results of extensive literature reviews, discussions, and formal scoring of recommendations for the care of children with pulmonary hypertension.

Portopulmonary hypertension

Portopulmonary hypertension (POPH) is the presence of pulmonary arterial hypertension in patients with portal hypertension. Among liver transplant (LT) candidates, reported incidence rates of POPH range from 4.5% to 8.5%. In patients with LT, intraoperative death and immediate post-LT mortality are feared clinical events when transplantation is attempted in the setting of untreated, moderate to severe POPH; therefore, POPH precludes LT unless the mean pulmonary artery pressure can be reduced to a safe level and right ventricular function optimized. Specific pulmonary artery vasodilator medications seem effective in reducing pulmonary artery pressures and improving right ventricular function and survival.

Oxidative stress and pulmonary changes in experimental liver cirrhosis

The use of carbon tetrachloride (CCl₄) in rats is an experimental model of hepatic tissue damage; which leads to fibrosis, and at the long term, cirrhosis. Cirrhosis is the consequence of progressive continued liver damage, it may be reversible when the damaging noxae have been withdrawn. The aim of this study is to evaluate the changes caused by cirrhosis in lung and liver, through the experimental model of intraperitoneal CCI₄ administration. We used 18 male Wistar rats divided into three groups: control (CO) and two groups divided by the time of cirrhosis induction by CCI₄: G1 (11 weeks), G2 (16 weeks). We found significant increase of transaminase levels and lipid peroxidation (TBARS) in liver and lung tissue and also increased antioxidant enzymes SOD and CAT, as well as the expression of TNF-α and IL-1β in the lung of cirrhotic animals. We observed changes in gas exchange in both cirrhotic groups. We can conclude that our model reproduces a model of liver cirrhosis, which causes alterations in the pulmonary system that leads to changes in gas exchange and size of pulmonary vessels.

Pulmonary hypertension in patients with congenital portosystemic venous shunt: a previously unrecognized association

BACKGROUND

Pulmonary arterial hypertension has been reported to be observed in association with acquired portal hypertension. However, the contribution of congenital anomalies occurring in the portal system to the development of pulmonary arterial hypertension remains to be elucidated.

METHODS

Nine patients with congenital portosystemic venous shunt were studied from January 1990 through September 2005.

RESULTS

Patent ductus venosus was detected in 5 patients, including 3 patients with an absence of the portal vein. The presence of either a gastrorenal or splenorenal shunt was evident in another 4 patients. Six patients had a history of hypergalactosemia with normal enzyme activities, as seen during neonatal screening. Six (66.7%) of the 9 patients were identified to have clinically significant pulmonary arterial hypertension (mean pulmonary artery pressure: 34-79 mm Hg; pulmonary vascular resistances: 5.12-38.07 U). The median age at the onset of pulmonary arterial hypertension was 12 years and 3 months. Histologic studies of lung specimens, which were available in 4 of the 9 patients with congenital portosystemic venous shunt, showed small arterial microthrombotic lesions in 3 patients. This characteristic finding was recognized even in the congenital portosystemic venous shunt patients without PAH.

CONCLUSIONS

This study demonstrated thromboembolic pulmonary arterial hypertension to be a crucial complication in congenital portosystemic venous shunt, and this pathologic state may be latently present in patients with pulmonary arterial hypertension of unknown etiology.

Hypertension portopulmonaire

INTRODUCTION

Porto-pulmonary hypertension (PoPH) is the association of pulmonary artery hypertension and portal hypertension. The diagnosis of PoPH is based on pulmonary haemodynamic criteria, obtained via right heart catheterisation, including an increase in mean pulmonary arterial pressure (> 25 mmHg) and in pulmonary vascular resistance (> 240 dyn.s.cm-5).

STATE OF THE ART

The exact pathophysiological mechanisms of PoPH are unknown. However, since PoPH has been reported in patients with non-hepatic portal hypertension, the factor that determines the development must be portal hypertension rather than liver disease per se. Moreover, no simple relationship has been identified between the degree of hepatic impairment and the severity of PoPH. The clinical presentation is non-specific with haemodynamic failure occurring at the end stage. As a consequence, screening by annual transthoracic echocardiography is highly recommended in potential liver transplant candidates. Therapy with prostacyclin analogues may partially relieve pulmonary arterial hypertension (PAH). Liver transplantation has an uncertain effect in PoPH and because PoPH is associated with a high perioperative mortality, moderate to severe PoPH remains a contraindication for liver transplantation.

PERSPECTIVES AND CONCLUSIONS

Recent advances in the management of PoPH have improved the prognosis. The safety and efficacy of oral endothelin receptor antagonists and oral phosphodiesterase inhibitors is currently under evaluation. A therapeutic approach utilising combinations of drugs should provide better long-term results.

Sildenafil decreased pulmonary arterial pressure but may have exacerbated portal hypertension in a patient with cirrhosis and portopulmonary hypertension

Portopulmonary hypertension is a recognized but uncommon complication of cirrhosis. Liver transplantation may be contraindicated in patients with severe portopulmonary hypertension. In order to decrease the pulmonary arterial pressure, intravenous administration of epoprostenol has been shown to provide substantial beneficial results in these patients. Additionally, a recent case report demonstrated that long-term oral administration of sildenafil decreased pulmonary arterial pressure, but its effects on splanchnic hemodynamics were not measured. We report on a patient with cirrhosis and portopulmonary hypertension and the changes in the hemodynamic status after an oral administration of sildenafil. This case report clearly delineates that sildenafil decreases pulmonary arterial pressure but may exacerbate portal hypertension and hyperdynamic circulation in patients with cirrhosis and portopulmonary hypertension.

Pulmonary hypertension as a result of asymptomatic portosystemic shunt

This report describes a patient with severe pulmonary hypertension accompanied by a congenital intrahepatic portosystemic shunt. Primary pulmonary hypertension was suspected initially because none of the classic symptoms of a portosystemic shunt were present. Physicians should note that disorders of the portal system may cause pulmonary hypertension even in the absence of symptoms suggesting liver disease.

Pulmonary hypertension associated with postoperative biliary atresia: report of two cases

The authors report on 2 patients with biliary atresia in whom pulmonary hypertension (PH) developed in the long-term follow-up after hepatoportoenterostomy. Both had portal hypertension and had undergone distal splenorenal shunt. Dyspnea developed around 14 to 15 years of age. Cardiac catheterization showed pulmonary artery pressure (PAP) of 99/37 (58) and 67/32 (48) mm Hg, respectively, which did not respond to vasodilators. One patient suffered from respiratory tract infection followed by right heart failure and subsequent death at 20 years of age. Postmortum histological findings exhibited severe thickening of the pulmonary artery wall. PH may grow insidiously even after successful hepatoportoenterostomy. Careful monitoring of PAP and hemodynamic response of PAP to vasodilators is essential for evaluating the reversibility of PH and making treatment decisions.

Moderate primary pulmonary hypertension in patients undergoing liver transplantation

Primary pulmonary hypertension (PPH) in patients with hepatic cirrhosis is often considered an unacceptable condition for liver transplantation because of increased morbidity and mortality during the procedure. We studied the incidence, characteristics, and final outcome of patients with PPH undergoing liver transplantation in our institution. Among the 226 patients undergoing 257 liver transplantations, eight (3.5%) fulfilled the conditions of PPH and responded to vasodilator therapy. Nitroglycerin 1.5 micrograms/kg produced a decrease in pulmonary vascular resistance index (PVRI) and mean pulmonary arterial pressure (MPAP) of 20% and 15%, respectively. Patients with PPH when compared with a matched group of patients without PPH had markedly increased hemodynamic changes in PVRI (P = 0.004) and MPAP (P = 0.0001) during and after the procedure. All patients with PPH required pulmonary vasodilator therapy after reperfusion of the new liver, while none in the group of patients without PPH required this therapy. Furthermore, after graft reperfusion, patients with PPH in which venovenous bypass was not used (n = 3), had a more compromised right ventricular function with a greater increase of central venous pressure (CVP) (90%) and MPAP (140%) when compared with patients with bypass or preservation of the recipient's vena cava (n = 5) in whom the increase of CVP and MPAP was 50% and 60%, respectively. Moderate PPH without a fixed level of pulmonary hypertension in patients undergoing liver transplantation is not related to an adverse outcome.

Case report: delayed resolution of severe pulmonary hypertension after isolated liver transplantation in a patient with cirrhosis

Pulmonary hypertension is now recognized to be a rare association of liver disease and portal hypertension. This report describes the slow resolution of symptomatic pulmonary hypertension in a 33-year-old woman with cirrhosis who underwent isolated liver transplantation. The patient survived the surgery and perioperative period without significant haemodynamic compromise. After liver transplantation, the patient was monitored with regular Doppler echocardiography. By 27 months the pulmonary hypertension had almost completely resolved. This observation is important, as it suggests that patients with severe pulmonary hypertension who survive the perioperative period may have an excellent outcome, although resolution may be slow.

Pulmonary hypertension in chronic liver disease

Pulmonary hypertension develops in approximately 2% of patients with portal hypertension. Diagnosis is often difficult and requires a high degree of clinical suspicion. Treatment of patients with portal and pulmonary hypertension is limited, and mean survival following diagnosis is approximately 15 months. The effect of liver transplantation on the natural history of disease is discussed.

Unexpected lethal pulmonary hypertension in a 5-year-old girl successfully treated for biliary atresia

There appears to be a relationship between portal and pulmonary hypertension. A 5-year-old girl treated for biliary atresia developed this combination unexpectedly and died of pulmonary hypertension. Established pulmonary hypertension has a poor prognosis, which underscores the importance of early diagnosis by regular screening.

Pulmonary arteriovenous shunting in children with liver disease

Pulmonary arteriovenous shunting (PAVS) with hypoxemia is a severe complication of cirrhosis that may regress after liver transplantation. We report PAVS in 25 children with cirrhosis and in 1 with portal vein obstruction; proof of shunting was obtained by technetium Tc 99m microaggregated albumin pulmonary scanning or a high alveoloarterial O2 gradient or both. Cyanosis or dyspnea or both occurred at ages ranging from 6 months to 14 years, earlier in children with biliary atresia and polysplenia syndrome (p < 0.01). Mean arterial oxygen tension (PaO2) was 57 mm Hg (range, 42 to 81 mm Hg) during breathing of 21% O2 and 367 mm Hg (range, 179 to 535 mm Hg) in 100% O2. Cardiac index was always raised, significantly more in children with biliary atresia and polysplenia syndrome (p < 0.01). Seven untreated children died 3 months to 8 years after the diagnosis of PAVS. Eleven underwent liver transplantation: seven are alive (follow-up, 1 to 4 years) and have no signs of PAVS. The PaO2 value during breathing of 100% O2 was > 300 mm Hg in the survivors and < 200 mm Hg in the four nonsurvivors (p < 0.01). These results indicate (1) that PAVS can occur at any age in children with portal hypertension, and that the risk is highest and earliest in children with biliary atresia and polysplenia syndrome, (2) that early liver transplantation allows regression of PAVS, and (3) that the prognosis may in part be related to the level of PaO2 while the patient is breathing 100% O2. The results indicate that systematic screening for PAVS should be part of the examination of these children.

Nodular transformation of the liver associated with portal and pulmonary arterial hypertension

A case of multiple focal nodular hyperplasia (FNH) of the liver associated with noncirrhotic portal hypertension and later complicated by pulmonary arterial hypertension leading to death from right heart failure is reported. In retrospect, the portal hypertension diagnosed in early life was most likely due to a congenital hypoplasia of portal vein branches and multiple FNH, a hyperplastic response of the liver parenchyma in association with anomalies of hepatic arterial branches as found within the lesions. This case may represent a form of multiple FNH syndrome restricted to the liver, because neither extrahepatic vascular malformation nor brain tumor was identified at autopsy. The FNH lesions had considerably expanded over the years, and the severe sinusoidal congestion due to chronic right-sided heart failure with subsequent prolonged parenchymal exposure to blood-borne hepatotrophic factors is a likely explanation for both the massive enlargement of FNH lesions and the nodular regenerative hyperplasia observed in the intervening parenchyma.

Long-term outcome after surgery for biliary atresia. Study of 40 patients surviving for more than 10 years

To define long-term prognosis of children who underwent surgery for biliary atresia, a retrospective study was undertaken in 122 children who underwent one of the Kasaï procedures between 1968 and 1977. Forty of the 122 children (32.7%) were alive after 10 years. Firm hepatomegaly was present in 31 and splenomegaly in 29 children. Serum bilirubin or all liver function tests were normal in 21 and 11 children, respectively; survival rate decreased with the age at operation, but no significant difference was observed in the rate of children surviving with normal serum bilirubin whether they underwent surgery before age 2 months or between 2 and 3 months. Twenty-four had esophageal varices and 15 experienced gastrointestinal bleeding. Normal liver-function tests and absence of portal hypertension were observed in 11 of 122 children. These results indicate that Kasaï's procedures were helpful in a significant proportion of children with biliary atresia who underwent surgery during this period. However, 80% of children who initially underwent surgery with Kasaï's procedures should eventually undergo liver transplantation.

Pulmonary hypertension associated with portal hypertension in childhood. Case report of a 6-year-old child and review of the literature

Pulmonary hypertension is a rare complication of portal hypertension. Reports of childhood cases especially rare. This report describes an autopsy case of a 6-year-old boy with congenital biliary atresia followed by liver cirrhosis in whom severe hypertensive pulmonary arterial changes, including medial hypertrophy, intimal fibrosis and plexiform lesions were demonstrated. Fresh and organizing fibrin-platelet thrombi as well as probable organized thrombi with recanalization were occasionally found in the pulmonary vasculature, but it was thought that they had probably been formed locally as a late complication rather than being of thromboembolic origin. Retrospectively, the chest roentgenograms had revealed abnormalities suggestive of pulmonary hypertension since infancy, but the patient showed no apparent symptoms of it during life. Previously reported childhood cases of pulmonary hypertension associated with portal hypertension were briefly reviewed. Although the mechanism is presently not known, it is suggested that patients with portal hypertension, even in early childhood, are at risk of developing this unusual complication.

Transplantation of liver, heart, and lungs for primary biliary cirrhosis and primary pulmonary hypertension

Liver, heart, and lung replacement was performed in a woman with severe pulmonary hypertension, cardiorespiratory failure, and end-stage primary biliary cirrhosis. The main surgical considerations were the staging of the various parts of the operation in relation to cardiopulmonary bypass and performing the recipient procedures as expeditiously as possible to reduce the bypass time to a minimum. The patient was able to leave hospital on the 46th postoperative day on low doses of immunosuppressive agents, with excellent liver and cardiopulmonary function. This early satisfactory outcome shows the feasibility and potential of the procedure: such combined allografting may be a suitable treatment in carefully selected cases of advanced liver and lung disease from other causes.