Microvascular optical assessment confirms the presence of peripheral autonomic dysfunction in primary biliary cirrhosis
ABSTRACT Autonomic dysfunction (AD) is a significant problem in primary biliary cirrhosis (PBC) and is equally present in early disease stages. Currently, AD in PBC is considered to be central in origin. The aim of this study was to examine peripheral mechanisms in the pathogenesis of AD in PBC using novel microvascular optical assessments for this patient group.
Twenty-four early stage PBC patients and 24 age-matched controls attended for two microvascular optical-based measurement techniques. Firstly, the regulation of microvascular blood volume to the periphery was assessed using multisite photoplethysmography (PPG) by examining the degree of correlation between the right and left sides of the body, with reduced correlation consistent with peripheral AD. Secondly, the peripheral vasomotor reflex response to standing was dynamically tested using laser Doppler flowmetry to quantify the degree of autonomic tone in peripheral vasoconstriction.
PBC patients had a significantly reduced right to left side blood volume multisite PPG correlation compared with controls when corrected for age, body mass index, heart rate and systolic blood pressure [impaired synchronization between pulse wave amplitude between right and left fingers and right and left ears (both P<0.05)]. The veno-arteriolar reflex on standing in PBC patients was significantly lower than for the controls, consistent with poorer autonomic tone for vasoconstriction in PBC (P<0.01).
This study provides evidence for the presence of peripheral autonomic nervous system involvement in PBC. Prospective studies are now warranted to determine the full clinical potential of microvascular optical assessment in PBC.
- Liver international: official journal of the International Association for the Study of the Liver 11/2009; 29(10):1451-3. DOI:10.1111/j.1478-3231.2009.02141.x · 4.41 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Cardiovascular system dysregulation in the form of autonomic dysfunction is common at all stages of the disease process in the autoimmune liver disease primary biliary cirrhosis (PBC) and associates with the symptom of fatigue. The mechanisms underpinning autonomic dysfunction in PBC are, however, at present unclear. In this study we set out to explore, for the first time, cardiac structure and function in PBC using impedance cardiography (ICG) and magnetic resonance methodologies. ICG was assessed beat to beat in response to orthostasis (by head-up tilt) in age and sex case-matched high-fatigue and low-fatigue PBC groups (assessed by Fatigue Impact Scale), normal control subjects (n = 15 each group) and a liver disease control cohort (primary sclerosing cholangitis). Cardiac structure and bioenergetics were examined in 15 of the PBC subjects and 8 of the normal control subjects by magnetic resonance spectroscopy and cine imaging. Capacity of the left ventricle to respond to orthostasis [left ventricular ejection time (LVET)] was impaired in PBC compared with matched normal control subjects (P = 0.05). This was a PBC-specific phenomenon unrelated to fatigue status. PBC patients exhibited significantly lower cardiac muscle phosphocreatine-to-ATP ratio (PCr/ATP ratio; measure of cardiac bioenergetic integrity) compared with control subjects (P < 0.01). PCr/ATP <1.6 (indicative of increased risk of death in cardiomyopathy) was present in 6/15 (40%) PBC patients (0/8 control subjects; P < 0.05). Cardiac structure and function were similar in all measures of left ventricular morphology between control subjects and PBC. The close relationship between PCr/ATP and LVET seen in normal subjects (r(2) = 0.6; P < 0.05) was lost in PBC patients, a finding compatible with myocardial dysfunction. Significant correlation was seen between fatigue severity in PBC and fall in cardiac output on orthostasis (r(2) = 0.25; P = 0.005). Our findings suggest the presence of altered myocardial function in PBC. Autonomic "dysfunction" may, rather than being an abnormal process, represent a compensatory mechanism to increase cardiac return to mitigate these effects.AJP Gastrointestinal and Liver Physiology 05/2010; 298(5):G764-73. DOI:10.1152/ajpgi.00501.2009 · 3.74 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Improved medical management and the changing disease demographic mean that the majority of patients with chronic liver disease are living with the disease rather than dying from it. Historically, the perception has been that the impact of chronic liver disease is related entirely to the consequences of endstage liver disease; however, more recently a number of systemic symptoms have been recognised that can occur at any point in the natural history of chronic liver disease and which can be associated with functional impairment and reduced quality of life. The most characteristic of these systemic symptoms is fatigue, which frequently associates with sleep disturbance and autonomic dysfunction, particularly manifest as abnormality of blood pressure regulation. Cognitive symptoms can occur even in non-cirrhotic patients. Falls can present in patients with autonomic dysfunction, complicated by the presence of peripheral muscle strength problems. Importantly for clinicians managing chronic liver disease, the severity of these systemic symptoms is typically not related to liver disease severity, and therefore despite optimal liver disease management, patients can often continue to experience debilitating symptoms. The similarity in systemic symptoms between different chronic liver diseases (and indeed chronic inflammatory conditions affecting other organs) suggests the possibility of shared pathogenetic processes and raises the possibility of common management strategies, although further research is urgently needed to confirm this. In primary biliary cirrhosis, where our understanding of systemic symptoms is arguably most developed, structured management strategies have been shown to improve the quality of life of patients. It is highly likely that similar approaches will have comparable benefits for other chronic liver disease groups. Here, we review the current understanding of systemic symptoms in chronic liver disease and offer recommendations regarding the successful management of these symptoms. Critical for successful treatment is use of a structured and systematic approach to management in which all contributing factors are addressed in an organised fashion. We believe that such a systematic approach, when applied to research as well as to clinical management, will allow us to reduce the overall burden of chronic liver disease, improve quality of life and enhance functional ability.Journal of Hepatology 01/2012; 56 Suppl 1:S46-55. DOI:10.1016/S0168-8278(12)60006-3 · 10.40 Impact Factor