Terlipressin-induced ventricular arrhythmia

Terlipressin in the management of adults with hepatorenal syndrome-acute kidney injury (HRS-AKI)

INTRODUCTION

Kidney is the most common extra-hepatic organ involved in patients with advanced liver cirrhosis and acute-on-chronic liver failure. Hepatorenal syndrome-acute kidney injury (HRS-AKI) accounts for most hospitalizations, and liver transplantation (LT) remains the ultimate and long-term treatment in such patients. However, HRS-AKI, being a functional renal failure, has a fair chance of reversal, and as such, patients who achieve reversal of HRS-AKI have better outcomes post-LT.

AREAS COVERED

In this review, we discuss the pharmacokinetics, pharmacodynamics and evidence to support the use of terlipressin in HRS-AKI while we also address predictors of response and the associated adverse events. Further, we discuss the role of terlipressin in the context of LT.

EXPERT OPINION

The recommended treatment for HRS-AKI reversal includes a vasoconstrictor in addition to volume expansion with albumin. The three vasoconstrictor regimens generally used to treat HRS-AKI include octreotide plus midodrine, noradrenaline, and terlipressin. Of these, terlipressin is a widely used drug and has been recently approved by US Food and Drug Administration (USFDA) for HRS-AKI. Terlipressin is the most effective drug for HRS-AKI reversal and is associated with a decreased need for renal replacement therapy pre- and post-transplant. Furthermore, terlipressin responders have improved transplant-free and post-transplant survival.

The Heart as a Target of Vasopressin and Other Cardiovascular Peptides in Health and Cardiovascular Diseases

The automatism of cardiac pacemaker cells, which is tuned, is regulated by the autonomic nervous system (ANS) and multiple endocrine and paracrine factors, including cardiovascular peptides. The cardiovascular peptides (CPs) form a group of essential paracrine factors affecting the function of the heart and vessels. They may also be produced in other organs and penetrate to the heart via systemic circulation. The present review draws attention to the role of vasopressin (AVP) and some other cardiovascular peptides (angiotensins, oxytocin, cytokines) in the regulation of the cardiovascular system in health and cardiovascular diseases, especially in post-infarct heart failure, hypertension and cerebrovascular strokes. Vasopressin is synthesized mostly by the neuroendocrine cells of the hypothalamus. There is also evidence that it may be produced in the heart and lungs. The secretion of AVP and other CPs is markedly influenced by changes in blood volume and pressure, as well as by other disturbances, frequently occurring in cardiovascular diseases (hypoxia, pain, stress, inflammation). Myocardial infarction, hypertension and cardiovascular shock are associated with an increased secretion of AVP and altered responsiveness of the cardiovascular system to its action. The majority of experimental studies show that the administration of vasopressin during ventricular fibrillation and cardiac arrest improves resuscitation, however, the clinical studies do not present consisting results. Vasopressin cooperates with the autonomic nervous system (ANS), angiotensins, oxytocin and cytokines in the regulation of the cardiovascular system and its interaction with these regulators is altered during heart failure and hypertension. It is likely that the differences in interactions of AVP with ANS and other CPs have a significant impact on the responsiveness of the cardiovascular system to vasopressin in specific cardiovascular disorders.

QT interval prolongation in liver cirrhosis: innocent bystander or serious threat?

The ECG QT interval measures the length of ventricular systole. Its prolongation is essentially caused by a delayed repolarization phase, and is associated with an increased risk of ventricular arrhythmias and sudden death in several congenital and acquired conditions. Abnormalities in cardiac electrophysiology are well documented in patients with liver cirrhosis, and the prolonged QT interval has emerged as the electrophysiological hallmark of cirrhotic cardiomyopathy. This article will focus on: first, the epidemiology of QT interval prolongation in cirrhosis; second, the potential molecular mechanisms responsible for the pathogenesis of this electrophysiological abnormality and the putative role of circulating cardiotoxins; third, its prognostic meaning; and fourth, its clinical relevance, in terms of the association between the presence of a long QT interval and the occurrence of ventricular arrhythmias in cirrhotic patients treated with drugs known to increase the QT length or exposed to stressful conditions, such as liver transplantation, gastrointestinal bleeding and shock.

[54-year-old male with hepatic cirrhosis and therapy-associated torsade de pointes tachycardia]

We present a case of a patient with newly diagnosed cirrhosis and kidney failure who underwent cardiopulmonary resuscitation twice after treatment with terlipressin. After the second application a QT interval prolongation and torsade de pointes were documented. Since other causes were excluded, we interpret both events as terlipressin-induced ventricular arrhythmia. Therefore, it seems important to consider this rare but potentially lethal side effect when administering this drug to patients.

Bench-to-bedside review: Vasopressin in the management of septic shock

This review of vasopressin in septic shock differs from previous reviews by providing more information on the physiology and pathophysiology of vasopressin and vasopressin receptors, particularly because of recent interest in more specific AVPR1a agonists and new information from the Vasopressin and Septic Shock Trial (VASST), a randomized trial of vasopressin versus norepinephrine in septic shock. Relevant literature regarding vasopressin and other AVPR1a agonists was reviewed and synthesized. Vasopressin, a key stress hormone in response to hypotension, stimulates a family of receptors: AVPR1a, AVPR1b, AVPR2, oxytocin receptors and purinergic receptors. Rationales for use of vasopressin in septic shock are as follows: first, a deficiency of vasopressin in septic shock; second, low-dose vasopressin infusion improves blood pressure, decreases requirements for norepinephrine and improves renal function; and third, a recent randomized, controlled, concealed trial of vasopressin versus norepinephrine (VASST) suggests low-dose vasopressin may decrease mortality of less severe septic shock. Previous clinical studies of vasopressin in septic shock were small or not controlled. There was no difference in 28-day mortality between vasopressin-treated versus norepinephrine-treated patients (35% versus 39%, respectively) in VASST. There was potential benefit in the prospectively defined stratum of patients with less severe septic shock (5 to 14 μg/minute norepinephrine at randomization): vasopressin may have lowered mortality compared with norepinephrine (26% versus 36%, respectively, P = 0.04 within stratum). The result was robust: vasopressin also decreased mortality (compared with norepinephrine) if less severe septic shock was defined by the lowest quartile of arterial lactate or by use of one (versus more than one) vasopressor at baseline. Other investigators found greater hemodynamic effects of higher dose of vasopressin (0.06 units/minute) but also unique adverse effects (elevated liver enzymes and serum bilirubin). Use of higher dose vasopressin requires further evaluation of efficacy and safety. There are very few studies of interactions of therapies in critical care - or septic shock - and effects on mortality. Therefore, the interaction of vasopressin infusion, corticosteroid treatment and mortality of septic shock was evaluated in VASST. Low-dose vasopressin infusion plus corticosteroids significantly decreased 28-day mortality compared with corticosteroids plus norepinephrine (44% versus 35%, respectively, P = 0.03; P = 0.008 interaction statistic). Prospective randomized controlled trials would be necessary to confirm this interesting interaction. In conclusion, low-dose vasopressin may be effective in patients who have less severe septic shock already receiving norepinephrine (such as patients with modest norepinephrine infusion (5 to 15 μg/minute) or low serum lactate levels). The interaction of vasopressin infusion and corticosteroid treatment in septic shock requires further study.

Low-dose vasopressin infusion results in increased mortality and cardiac dysfunction following ischemia-reperfusion injury in mice

Introduction

Arginine vasopressin is a vasoactive drug commonly used in distributive shock states including mixed shock with a cardiac component. However, the direct effect of arginine vasopressin on the function of the ischemia/reperfusion injured heart has not been clearly elucidated.

Methods

We measured left ventricular ejection fraction using trans-thoracic echocardiography in C57B6 mice, both in normal controls and following ischemia/reperfusion injury induced by a one hour ligation of the left anterior descending coronary artery. Mice were treated with one of normal saline, dobutamine (8.33 μg/kg/min), or arginine vasopressin (0.00057 Units/kg/min, equivalent to 0.04 Units/min in a 70 kg human) delivered by an intraperitoneal micro-osmotic pump. Arterial blood pressure was measured using a micromanometer catheter. In addition, mortality was recorded and cardiac tissues processed for RNA and protein.

Results

Baseline left ventricular ejection fraction was 65.6% (60 to 72). In normal control mice, there was no difference in left ventricular ejection fraction according to infusion group. Following ischemia/reperfusion injury, AVP treatment significantly reduced day 1 left ventricular ejection fraction 46.2% (34.4 to 52.0), both in comparison with baseline and day 1 saline treated controls 56.9% (42.4 to 60.2). There were no significant differences in preload (left ventricular end diastolic volume), afterload (blood pressure) or heart rate to account for the effect of AVP on left ventricular ejection fraction. The seven-day mortality rate was highest in the arginine vasopressin group. Following ischemia/reperfusion injury, we found no change in cardiac V1 Receptor expression but a 40% decrease in Oxytocin Receptor expression.

Conclusions

Arginine vasopressin infusion significantly depressed the myocardial function in an ischemia/reperfusion model and increased mortality in comparison with both saline and dobutamine treated animals. The use of vasopressin may be contraindicated in non-vasodilatory shock states associated with significant cardiac injury.

Efficacy and safety of terlipressin in cirrhotic patients with variceal bleeding or hepatorenal syndrome

Terlipressin is an analog of the natural hormone arginine-vasopressin. It is used in the treatment of patients with cirrhosis and bleeding esophageal varices (BEV) and in patients with hepatorenal syndrome (HRS): two of the most dramatic and feared complications of cirrhosis. Terlipressin exerts its main pharmacological effect through stimulation of vasopressin-1 receptors. These receptors are located in vascular smooth muscle and mediate vasoconstriction. In patients with cirrhosis and portal hypertension, treatment with terlipressin increases mean arterial pressure and decreases portal flow and pressure within minutes of administration. Furthermore, in patients with ascites terlipressin improves glomerular filtration and excretion of sodium. Terlipressin decreases failure of initial hemostasis by 34%, decreases mortality by 34%, and is considered a first-line treatment for BEV, when available. Terlipressin in combination with albumin reverses type 1 HRS in 33%-60% of cases and is the only treatment with proven efficacy in randomized trials. The safety profile is favorable when considering the clinical efficacy and the high mortality of these clinical entities. Adverse events are mostly cardiovascular and related to vasoconstriction. Mortality and withdrawal of terlipressin due to adverse events occurs in less than 1% of cases. Mild adverse events related to terlipressin treatment occur in 10%-20% of patients. The benefit, however, of terlipressin on long-term survival in HRS remains to be determined. At present, treatment with terlipressin and albumin is considered the most efficient therapy and should therefore be recommended for the treatment of type 1 HRS-1.