Reduced thoracic fluid content in early-stage primary biliary cirrhosis that associates with impaired cardiac inotropy

Risk of Cardiovascular Events in Patients with Primary Biliary Cholangitis - Systematic Review

Background and Aims: Hypercholesterolemia is a common finding in patients with primary biliary cholangitis (PBC) and is a well-defined risk factor for cardiovascular disease. However, studies have been mixed on whether PBC patients do, in fact, have higher cardiovascular risk. The aim of this study is to review the current literature and provide an evidence-based assessment of cardiovascular risk in PBC patients. Methods: We performed a systematic literature search on PubMed regarding patients with PBC and cardiovascular events from the database inception to July 1, 2017. A total of 33 articles fulfilling our inclusion criteria were found. Results: The majority of the studies evaluated yielded no statistically significant difference in cardiovascular disease in the PBC population compared to the general public. However, some reports found a statistically significantly increase in coronary artery disease. Several studies have looked at the specific lipid profile of patients with PBC with hypocholesteremia. While these lipid abnormalities differ by stage of disease, there is evidence to suggest that the specific lipid profile in PBC may have lower atherogenicity than in patients with hypercholesterolemia without PBC. Studies looking at patients with PBC with other risk factors for cardiovascular disease, such as hypertension and metabolic syndrome, have consistently found a higher risk for cardiovascular disease in these patients. Statin treatment is effective in reducing lipid levels and possibly improving endothelial inflammation in patients with PBC with hypercholesterolemia. Conclusions: There is not enough evidence to suggest an increased risk of cardiovascular disease in patients with PBC with hypercholesterolemia, except for those individuals with concomitant features of metabolic syndrome. In patients with PBC with no additional cardiovascular risk factors, individual risk/benefit discussion on lipid-lowering treatment should be considered.

Heart and bile acids - Clinical consequences of altered bile acid metabolism

Cardiac dysfunction has an increased prevalence in diseases complicated by liver cirrhosis such as primary biliary cholangitis and primary sclerosing cholangitis. This observation has led to research into the association between abnormalities in bile acid metabolism and cardiac pathology. Approximately 50% of liver cirrhosis cases develop cirrhotic cardiomyopathy. Bile acids are directly implicated in this, causing QT interval prolongation, cardiac hypertrophy, cardiomyocyte apoptosis and abnormal haemodynamics of the heart. Elevated maternal serum bile acids in intrahepatic cholestasis of pregnancy, a disorder which causes an impaired feto-maternal bile acid gradient, have been associated with fatal fetal arrhythmias. The hydrophobicity of individual bile acids in the serum bile acid pool is of relevance, with relatively lipophilic bile acids having a more harmful effect on the heart. Ursodeoxycholic acid can reverse or protect against these detrimental cardiac effects of elevated bile acids.

Preejection Period as a Sympathetic Activity Index: a Role of Confounding Factors

In previous studies, one of the systolic time intervals – preejection period (PEP) – was used as an index of sympathetic activity reflecting the cardiac contractility. However, PEP could be also influenced by several other cardiovascular variables including preload, afterload and diastolic blood pressure (DBP). The aim of this study was to assess the behavior of the PEP together with other potentially confounding cardiovascular system characteristics in healthy humans during mental and orthostatic stress (head-up tilt test – HUT). Forty-nine healthy volunteers (28 females, 21 males, mean age 18.6 years (SD=1.8 years)) participated in the study. We recorded finger arterial blood pressure by volume-clamp method (Finometer Pro, FMS, Netherlands), PEP, thoracic fluid content (TFC) – a measure of preload, and cardiac output (CO) by impedance cardiography (CardioScreen® 2000, Medis, Germany). Systemic vascular resistance (SVR) – a measure of afterload – was calculated as a ratio of mean arterial pressure and CO. We observed that during HUT, an expected decrease in TFC was accompanied by an increase of PEP, an increase of SVR and no significant change in DBP. During mental stress, we observed a decrease of PEP and an increase of TFC, SVR and DBP. Correlating a change in assessed measures (delta values) between mental stress and previous supine rest, we found that ΔPEP correlated negatively with ΔCO and positively with ΔSVR. In orthostasis, no significant correlation between ΔPEP and ΔDBP, ΔTFC, ΔCO, ΔMBP or ΔSVR was found. We conclude that despite an expected increase of sympathetic activity during both challenges, PEP behaved differently indicating an effect of other confounding factors. To interpret PEP values properly, we recommend simultaneously to measure other variables influencing this cardiovascular measure.

Risk of incident coronary artery disease in patients with primary biliary cirrhosis

BACKGROUND

Patients with primary biliary cirrhosis (PBC) often present hyperlipidemia, which is a risk factor of incident coronary artery disease (CAD). However, few studies have examined CAD in PBC.

METHODS

We identified 41 patients who developed CAD amongst 2,675 PBC cases across seven years and selected the PBC patients without CAD as controls according to sex and age.

RESULTS

Females dominated in these patients with CAD. The median time from the diagnosis of PBC to the onset of CAD was 44 months. The patient group with CAD had higher median levels of low-density lipoprotein cholesterol (4.68 mmol/L versus 3.52 mmol/L, P=0.036) and higher proportion of cases with hypertension (63.4% versus 19.5%, P<0.001) compared to that without CAD. In the logistic regression, only hypertension (with versus without, P<0.001; OR, 1.597; 95% CI, 1.139-2.053) was selected.

CONCLUSION

PBC patients with hypertension should be monitored carefully due to the risk of incident CAD.