Systematic review: pre- and post-operative prognostic value of cardiopulmonary exercise testing in liver transplant candidates

Impact of beta-blockers on cardiopulmonary exercise testing in patients with advanced liver disease

BACKGROUND

Patients with advanced liver disease may develop portal hypertension that can result in variceal haemorrhage. Beta-blockers reduce portal pressure and minimise haemorrhage risk. These medications may attenuate measures of cardiopulmonary performance, such as the ventilatory threshold and peak oxygen uptake measured via cardiopulmonary exercise testing.

AIM

To determine the effect of beta-blockers on cardiopulmonary exercise testing variables in patients with advanced liver disease.

METHODS

This was a cross-sectional analysis of 72 participants who completed a cardiopulmonary exercise test before liver transplantation. All participants remained on their usual beta-blocker dose and timing prior to the test. Variables measured during cardiopulmonary exercise testing included the ventilatory threshold, peak oxygen uptake, heart rate, oxygen pulse, the oxygen uptake efficiency slope and the ventilatory equivalents for carbon dioxide slope.

RESULTS

Participants taking beta-blockers (n = 28) had a lower ventilatory threshold (P <.01) and peak oxygen uptake (P = .02), compared to participants not taking beta-blockers. After adjusting for age, the model of end-stage liver-disease score, liver-disease aetiology, presence of refractory ascites and ventilatory threshold remained significantly lower in the beta-blocker group (P = .04). The oxygen uptake efficiency slope was not impacted by beta-blocker use.

CONCLUSIONS

Ventilatory threshold is reduced in patients with advanced liver disease taking beta-blockers compared to those not taking the medication. This may incorrectly risk stratify patients on beta-blockers and has implications for patient management before and after liver transplantation. The oxygen uptake efficiency slope was not influenced by beta-blockers and may therefore be a better measure of cardiopulmonary performance in this patient population.

A practical approach to nutritional screening and assessment in cirrhosis

Malnutrition is one of the most common complications of cirrhosis, associated with an increased risk of morbidity and mortality. As a potentially modifiable condition, it is of particular importance to identify malnourished patients so that nutritional therapy can be instituted. Nutrition screening and assessment are infrequently performed in patients with cirrhosis. The reasons for this are multifactorial, including the absence of a validated "rapid" screening tool, multiple definitions of what constitutes malnutrition, and challenges with interpreting body composition and laboratory results in the setting of volume overload and liver dysfunction. This article summarizes the clinically relevant evidence and presents key issues, tools, and clinical options that are applicable to patients with cirrhosis. The definition, etiology, and clinically relevant outcomes associated with malnutrition are reviewed. Rapid nutritional screening is differentiated from more detailed nutritional assessment. Nutritional assessment in special populations, including women and the obese, and the role of inflammation are discussed. Multicenter studies using a common nutritional screening/assessment strategy are the next steps to fast-track adoption and implementation of nutrition-related evaluations into routine clinical practice. (Hepatology 2017;65:1044-1057).