Assessment of acute pulmonary vascular reactivity in portopulmonary hypertension

Cardiology Assessment of Patients Undergoing Evaluation for Orthotopic Liver Transplantation

Orthotopic liver transplantation (OLT) is a viable treatment option for end-stage liver disease. Significant perioperative stress is placed on the cardiovascular system because of hemodynamic changes and the length of the operation. Diagnosis and treatment of cardiovascular disease before OLT are imperative to ensure favorable outcomes. Considerable variability exists among practitioners caring for these patients. Institutions tailor their protocols on the basis of local and historical practices, the preferences of the cardiologists, and the OLT team, and algorithms are not often revised or updated on the basis of the available evidence. In collaboration with cardiology and hepatology experts from leading OLT centers, we sought to examine the diagnostic cardiovascular workup of OLT candidates, including a review of the available literature on the diagnostic modalities used to screen cardiovascular disease before OLT. We advocate an emphasis on noninvasive methods to assess cardiovascular risk with reserved use of invasive risk stratification in select patients.

International Liver Transplant Society Practice Guidelines: Diagnosis and Management of Hepatopulmonary Syndrome and Portopulmonary Hypertension

Two distinct pulmonary vascular disorders, hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) may occur as a consequence of hepatic parenchymal or vascular abnormalities. HPS and POPH have major clinical implications for liver transplantation. A European Respiratory Society Task Force on Pulmonary-Hepatic Disorders convened in 2002 to standardize the diagnosis and guide management of these disorders. These International Liver Transplant Society diagnostic and management guidelines are based on that task force consensus and should continue to evolve as clinical experience dictates. Based on a review of over 1000 published HPS and POPH articles identified via a MEDLINE search (1985-2015), clinical guidelines were based on, selected single care reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Guidelines are presented in 5 parts; I. Definitions/Diagnostic criteria; II. Hepatopulmonary syndrome; III. Portopulmonary hypertension; IV. Implications for liver transplantation; and V. Suggestions for future clinical research.

Hemodynamic profile of portopulmonary hypertension

Portopulmonary hypertension (PPHTN) refers to the development of pulmonary arterial hypertension in the setting of portal hypertension with or without chronic hepatic failure. This syndrome is characterized by marked alternations of pulmonary vascular tone and obstruction of pulmonary arterial blood flow. An increased pulmonary blood flow, which is a hallmark of the hyperdynamic circulation of cirrhotic patients, seems to be present in almost all patients who develop PPHTN. The elevations of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) along with the transpulmonary gradient (TPG) have been considered in diagnosing PPHTN. Only a high TPG reflects the severity of obstruction to pulmonary blood flow and differentiates an elevated PAP with concomitant elevated PVR from the situation where the increase in PAP is due only to the hyperdynamic flow and elevated volume. A considerable risk for cardiovascular death arises when PAP increases significantly; this may occur in rapidly evolving syndromes, in very advanced disease, or during a complicated liver transplantation. The distinction between PPHTN and elevated PAP in the context of a hyperdynamic state is of great importance; a PAP increase of hyperkinetic origin, as opposed to PPHTN, is apparently not associated with a high risk for adverse effects during and following liver transplantation.

Variability in hemodynamic evaluation of pulmonary hypertension at large referral centers

Despite consensus guidelines for right heart catheterization (RHC) in the diagnosis of pulmonary arterial hypertension (PAH), considerable differences exist in the performance of RHC, interpretation of hemodynamic data, and frequency of RHC performance in patients with established disease. These differences may lead to variability in diagnosis or treatment of PAH. We sought to gather information on the standard practice of RHC for the diagnosis and management of PAH from experienced pulmonary vascular disease specialists. We developed a semiquantitative online survey of diagnosis and treatment patterns of pulmonary hypertension and distributed it to physicians at pulmonary hypertension centers in the United States. Thirty of 50 physicians completed the survey: 20 pulmonologists and 10 cardiologists, all of whom reported treating >100 patients with PAH in the past year. All respondents perform RHC in ≥90% of patients with suspected PAH. All physicians determine the pulmonary wedge pressure at end expiration; however, only half of respondents personally review tracings. Physicians differed in frequency of vasodilator testing (8 of 24 performed testing in >90% of patients with PAH), fluid challenge and exercise (19 of 30 performed testing in <25% of patients with PAH for both). Most physicians (70%) report repeating RHC between 6 months and 1 year after PAH treatment initiation. Variability exists in the interpretation of hemodynamic tracings and performance of vasodilator, fluid, and exercise challenges in the management of PAH by experienced physicians in the United States. Additional consensus guidelines delineating appropriate adjunctive testing to standardize the diagnosis of PAH are needed.

Living-donor liver transplantation for congenital biliary atresia with porto-pulmonary hypertension and moderate or severe pulmonary arterial hypertension: Kyoto University experience

Porto-pulmonary hypertension with moderate or severe pulmonary arterial hypertension (PAH) is viewed as a contraindication to liver transplantation (LT) because of associated poor outcomes; however, patients with biliary atresia (BA) are generally good candidates for LT. Ten patients with moderate/severe PAH underwent living-donor liver transplantation (LDLT) at our institution; eight of these patients had BA and were the focus of this study. Preoperative therapies, including prostaglandin (PG)I2 , were introduced. When mean pulmonary arterial pressure (mPAP) after treatment was <40 mmHg or initial mPAP without therapy was <35 mmHg, we performed an acute volume challenge test to evaluate right ventricular function. LDLT was performed when mPAP after anesthetic induction was confirmed at ≤35 mmHg. Six patients had favorable responses to preoperative treatment and catheter testing, but two patients showed poor responses. The two patients with poor responses had poor clinical courses with unstable mPAP after LDLT. The other six patients had successful courses with well-controlled mPAP, and PGI2 was withdrawn or weaned following LDLT. Survival did not significantly differ between the eight BA recipients with moderate/severe PAH and 77 age-matched BA recipients without PAH from the same time period. LDLT has major benefits for BA patients with well-controlled PAH.

Pulmonary contraindications, indications and MELD exceptions for liver transplantation: a contemporary view and look forward

Pulmonary concerns in liver transplant candidates have intraoperative and outcome implications. Evolving MELD exception policies address transplant priority for problems such as hepatopulmonary syndrome, portopulmonary hypertension, and hemorrhagic hereditary telangiectasia. Other pulmonary issues such as refractory hepatic hydrothorax, advanced chronic obstructive lung disease (including alpha-1 antitrypsin deficiency) and indeterminate pulmonary nodules may affect liver transplant consideration. Herein, we discuss current pulmonary-related contraindications, indications and MELD exception policies for liver transplantation, suggesting future considerations.

Living-donor liver transplantation for moderate or severe porto-pulmonary hypertension accompanied by pulmonary arterial hypertension: a single-centre experience over 2 decades in Japan

BACKGROUND

Candidates for orthotopic liver transplantation (OLT) often have porto-pulmonary hypertension (PPHTN) with pulmonary arterial hypertension (PAH). Poor outcomes of PPHTN contraindicate OLT. There are no guidelines for living-donor liver transplantation (LDLT) in PPHTN patients.

METHODS

We present our experiences of LDLT in six patients with moderate or severe PPHTN, along with our institutional guidelines. Three had liver cirrhosis and three were non-cirrhotic. Catheterization studies were undertaken before, during and after LDLT, and the mean pulmonary arterial pressure (mPAP), cardiac output (CO), pulmonary vascular resistance and total peripheral resistance (TPR) were monitored.

RESULTS

The results showed significant differences in CO and TPR between cirrhotic and non-cirrhotic patients before, during and after LDLT. Cirrhotic patients showed systemic hyperdynamic state. Two cirrhotic patients showed poor responses to pre-transplant treatment, and continued to have increased PAH and poor clinical courses after LDLT. LDLT has an advantage of flexible timing of LT. Currently in our institution, PPHTN patients with mPAP <40 mmHg are registered for LDLT after treatment and catheterization. However, LDLT is performed when mPAP is ≤35 mmHg, leading to improved outcomes.

CONCLUSION

PPHTN patients with well-controlled PAH, or secondary PAH resulting from porto-systemic shunts, may be appropriate candidates for LDLT after careful considerations.

Portopulmonary hypertension: an update

Portopulmonary hypertension (POPH) is a serious complication of cirrhosis that is associated with mortality beyond that predicted by the Model for End-Stage Liver Disease (MELD) score. Increased pulmonary vascular resistance (PVR) may be initiated by pulmonary vasoconstriction, altered levels of circulating mediators, or shear stress, and can eventually lead to the classic vascular remodeling (plexiform lesion) that characterizes POPH. Portal hypertension is a prerequisite for the diagnosis of POPH, although the severity of pulmonary hypertension is unrelated to the severity of portal hypertension or the nature or severity of liver disease. POPH precludes liver transplantation (LT) unless the mean pulmonary artery pressure (MPAP) can be reduced to a safe level. The concept of an acceptable pressure has changed: we now consider both MPAP and PVR in the diagnosis, and we include the transpulmonary pressure gradient so that we can factor in fluid overload and left ventricular failure. Pulmonary vasodilator therapy includes oral, inhaled, and parenteral agents, and one or more of these agents may significantly lower pulmonary artery pressures to the point that LT becomes possible. The United Network for Organ Sharing recommends MELD exception points for patients with medically controlled POPH, but this varies by region. Patients who undergo LT need specialized intraoperative and postoperative management, which includes the availability of intraoperative transesophageal echocardiography for assessing right ventricular function, and rapidly acting vasodilators (eg, inhaled nitric oxide and/or epoprostenol). Published case series suggest excellent outcomes after LT for patients who respond to medical therapy.

Portopulmonary hypertension: from diagnosis to treatment

Portopulmonary hypertension is a form of pulmonary arterial hypertension that has gained interest in recent years with the development of liver transplantation techniques and new pulmonary vasodilator therapies. Portopulmonary hypertension is defined as pulmonary artery hypertension associated with portal hypertension with or without advanced hepatic disease. Echocardiography plays a major role in screening for portopulmonary hypertension but right heart catheterization remains the gold standard for diagnosis. The treatment of patients with portopulmonary hypertension consists of general measures that apply to all patients that carry the diagnosis of pulmonary hypertension and specific vasodilator therapies. These new therapies showed encouraging results in patients who would otherwise have a contraindication for liver transplantation. The review presents a summary of the current knowledge on the epidemiology, diagnosis, treatment and prognosis of patients with portopulmonary hypertension.

Portopulmonary hypertension

Portopulmoanry hypertension (POPH) is a form of pulmonary arterial hypertension (PAH) associated with portal hypertension with or without underlying chronic liver disease. POPH is increasingly recognized and recent evidence suggests that it is one of the leading causes of PAH. The pathophysiology of POPH is poorly understood although the pathological changes in pulmonary vasculature in advanced POPH are similar to those seen in idiopathic pulmonary hypertension. The prognosis in patients with liver disease who also suffer from significant POPH is considered to be poor. Higher degree of pulmonary artery pressure (PAP) may preclude a patient from liver transplant as mortality in these patients is high. The treatment with vasodilator therapy has shown to improve both hemodynamics and clinical outcome in POPH in retrospective studies and in some case series. The aim of medical management is to bring PAP <35 mmHg that may make a patient with POPH and advanced liver disease eligible for liver transplant, which otherwise would have been denied because of high PAP.

The heart in liver transplantation

The heart and liver are organs that are closely related in both health and disease. Patients who undergo liver transplantation may suffer from heart disease that is: (a) related to the original cause of the liver disease such as hemochromatosis, (b) related to the liver disease itself, or (c) related to other associated conditions. Furthermore, liver transplantation is one of the most cardiovascular stressful events that a patient with cirrhosis may undergo. After liver transplantation, the progression of pre-existing or the development of new-onset cardiac disease may occur. This article reviews the relationship between the heart and liver transplantation in the pre-transplant, intra-operative, and post-transplant periods.

Portopulmonary hypertension and right heart failure in patients with cirrhosis

PURPOSE OF REVIEW

In 5-6% of patients with portal hypertension a pathological state exists in which changes in the pulmonary vasculature cause an increase in pulmonary vascular resistance. The resultant increased work of the right ventricle may cause right heart failure and liver congestion. Patients with cirrhosis are at increased risk of mortality and transplant graft failure. The present review examines the latest advances in diagnosis, treatment and management of portopulmonary hypertension.

RECENT FINDINGS

Portopulmonary hypertension may be screened with transthoracic echocardiography and following up with a right heart catheterization in patients in whom the right ventricular systolic pressure is calculated to be 50 mmHg or greater. Therapy with prostanoids, endothelin-1 inhibitors and phosphodiesterase-5 inhibitors, or a combination of therapies, may be very effective in moderating pulmonary artery hypertension and, in selected patients, allowing liver transplantation to proceed safely. The model for end-stage liver disease (MELD) score is being weighted to accelerate responders on the waiting list for a transplant.

SUMMARY

Advances in diagnosis and therapy of portopulmonary hypertension allow patients with cirrhosis who respond to vasodilators to undergo liver transplantation safely. Unfortunately liver transplantation does not always result in reversal of pulmonary hypertension. There are now reports of de-novo pulmonary hypertension after liver transplantation.

Pulmonary complications in liver disease

Pulmonary complications of liver disease are poorly understood and often identified late. Abnormalities of the pulmonary vasculature lead to two distinct complications, hepatopulmonary syndrome and portopulmonary hypertension, which differ in their clinical features and management. This article focuses on these two entities.

Acute and long-term effects of inhaled iloprost in portopulmonary hypertension

Portopulmonary hypertension (PoPH) is a serious condition without an established treatment. Drugs used to treat pulmonary hypertension may have detrimental effects on portal hypertension. This study was designed to assess in patients with PoPH the acute effects of inhaled iloprost (iILO) on pulmonary and hepatic hemodynamics and to evaluate the clinical outcome after 12 months of treatment. We conducted 2 separate studies. In the first one, 21 patients with PoPH were acutely tested with 2.8 microg of iILO. Pulmonary and hepatic hemodynamics were assessed at the baseline and through 60 minutes after iILO. In the second one, we retrospectively evaluated 12 patients treated with iILO (30 microg/day) for more than 1 year. The 6-minute walk distance (6MWD), functional class (FC), and echocardiogram were analyzed at the baseline and after 12 months of treatment. In the acute study, iILO rapidly reduced pulmonary artery pressure (PAP; -16% + or - 8%, P < 0.001) and pulmonary vascular resistance (-18% + or - 14%, P < 0.001). The cardiac output did not change initially but decreased after 30 minutes. The hepatic venous pressure gradient (HVPG) and hepatic blood flow did not vary through the study. Pulmonary vasodilation induced by iILO was inversely related to HVPG. In the long-term evaluation, iILO improved FC by 1 or more in 7 patients (P = 0.04) and increased 6MWD by 67 + or - 59 m at 12 months (P < 0.001). No change in systolic PAP was observed. Two patients died because of hepatic complications, and 4 additional patients presented clinically significant events that were related to hepatic disease in 2 and worsening of pulmonary hypertension in 2. We conclude that in patients with PoPH, iILO produces rapid and selective pulmonary vasodilation without altering the hepatic hemodynamics. Its long-term use may provide sustained improvements in symptoms and exercise tolerance in some patients with PoPH. A randomized, controlled trial is warranted to establish its clinical role in this serious condition.

Intraoperative pulmonary hypertension occurred in an asymptomatic patient with pre-existent liver cirrhotic and portal hypertension

Portopulmonary hypertension (PPH) is clinically defined as the development of pulmonary arterial hypertension complicated by portal hypertension, with or without advanced hepatic disease. Physical signs may be absent in mild to moderate PPH and only appear in a hyperdynamic circulatory state. Similar signs of advanced liver disease can be observed in severe PPH, with ascites and lower extremity edema. Pulmonary hypertension is usually diagnosed after anesthetic induction during liver transplantation (LT). We present intraoperative pulmonary hypertension in a 41-year-old male patient with hepatic cirrhosis. Since this patient had no preoperation laboratory data supporting the diagnosises of pulmonary hypertension and was asymptomatic for a number of years, it was necessary to send him to the intensive care unit after operation. Further study should be focued on the diagnosis and treatment of pulmonary arterial hypertension in order to reduce its mortality.

Anesthetic management of hepatic transplantation

PURPOSE OF REVIEW

The present review describes new trends and ongoing controversies in the anesthetic care of liver transplant recipients.

RECENT FINDINGS

Recent studies have improved our knowledge of conditions increasing perioperative risk, such as portopulmonary hypertension and renal failure. Improved surgical and anesthetic management has reduced intraoperative blood loss, as more studies identify an independent association between blood transfusion and poor outcome. New concepts in the coagulopathy of liver failure are emerging, with clear implications for clinical practice, including greater awareness of the risks of intraoperative thromboembolism. Less invasive intraoperative hemodynamic monitoring has been advocated, as has wider use of transoesophageal echocardiography. Early extubation is becoming more routinized.

SUMMARY

Anesthetic management still varies widely between liver transplant centers with little data to indicate best practice. Future research should focus on fluid replacement, prevention and treatment of coagulopathy, care of the acutely ill patient and the safety and benefits of early extubation.

Initial experience using continuous intravenous treprostinil to manage pulmonary arterial hypertension in patients with end-stage liver disease

Treprostinil is a prostacyclin analog and has been used on idiopathic pulmonary arterial hypertension (PAH). There is only limited clinical experience using treprostinil to manage PAH in patients with end-stage liver disease (ESLD). We report three ESLD patients with PAH, who were treated with continuous intravenous treprostinil. A 59-year-old woman with ESLD secondary to alcoholic hepatitis had portopulmonary hypertension with mean pulmonary arterial pressure (mPAP) of 44 mmHg and transpulmonary gradient (TPG) of 23 mmHg. Treprostinil at 45 ng/kg/min for 6 months decreased mPAP to 23 (TPG to 8). A 53-year-old man had ESLD secondary to alcoholic hepatitis with PAH caused by multiple pulmonary embolisms (mPAP of 32 and TPG of 23). Treprostinil at 36 ng/kg/min for 3 months decreased mPAP to 23 and TPG to 14. Both patients underwent uneventful liver transplantation. A 48-year-old man had ESLD secondary to hepatitis C and portopulmonary hypertension with mPAP of 60 and TPG of 44. Two years after intravenous treprostinil at 106 ng/kg/min, his mPAP decreased to 44 and TPG to 30. These results demonstrate that for a selected group of ESLD patients with PAH, a continuous intravenous infusion of treprostinil appears to be safe and effective.