Aortic valve sclerosis as a marker of atherosclerosis: Novel insights from hepatic steatosis

MASLD: a systemic metabolic disorder with cardiovascular and malignant complications

Non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common chronic liver disease globally and is currently estimated to affect up to 38% of the global adult population. NAFLD is a multisystem disease where systemic insulin resistance and related metabolic dysfunction play a pathogenic role in the development of NAFLD and its most relevant liver-related morbidities (cirrhosis, liver failure and hepatocellular carcinoma) and extrahepatic complications, such as cardiovascular disease (CVD), type 2 diabetes mellitus, chronic kidney disease, and certain types of extrahepatic cancers. In 2023, three large multinational liver associations proposed that metabolic dysfunction-associated steatotic liver disease (MASLD) should replace the term NAFLD; the name chosen to replace non-alcoholic steatohepatitis was metabolic dysfunction-associated steatohepatitis (MASH). Emerging epidemiological evidence suggests an excellent concordance rate between NAFLD and MASLD definitions-that is, ~99% of individuals with NAFLD meet MASLD criteria. In this narrative review, we provide an overview of the literature on (a) the recent epidemiological data on MASLD and the risk of developing CVD and malignant complications, (b) the underlying mechanisms by which MASLD (and factors strongly linked with MASLD) may increase the risk of these extrahepatic complications and (c) the diagnosis and assessment of CVD risk and potential treatments to reduce CVD risk in people with MASLD or MASH.

Liver stiffness as a cornerstone in heart disease risk assessment

Metabolic dysfunction-associated steatotic liver disease (MASLD) typically presents with hepatic fibrosis in advanced disease, resulting in increased liver stiffness. A subset of patients further develops liver cirrhosis and hepatocellular carcinoma. Cardiovascular disease is a common comorbidity in patients with MASLD and its prevalence is increasing in parallel. Recent evidence suggests that especially liver stiffness, whether or not existing against a background of MASLD, is associated with heart diseases. We conducted a narrative review on the role of liver stiffness in the prediction of highly prevalent heart diseases including heart failure, cardiac arrhythmias (in particular atrial fibrillation), coronary heart disease, and aortic valve sclerosis. Research papers were retrieved from major scientific databases (PubMed, Web of Science) until September 2023 using 'liver stiffness' and 'liver fibrosis' as keywords along with the latter cardiac conditions. Increased liver stiffness, determined by vibration-controlled transient elastography or hepatic fibrosis as predicted by biomarker panels, are associated with a variety of cardiovascular diseases, including heart failure, atrial fibrillation, and coronary heart disease. Elevated liver stiffness in patients with metabolic liver disease should lead to considerations of cardiac workup including N-terminal pro-B-type natriuretic peptide/B-type natriuretic peptide determination, electrocardiography, and coronary computed tomography angiography. In addition, patients with MASLD would benefit from heart disease case-finding strategies in which liver stiffness measurements can play a key role. In conclusion, increased liver stiffness should be a trigger to consider a cardiac workup in metabolically compromised patients.

FIB-4 liver fibrosis index correlates with aortic valve sclerosis in non-alcoholic population

AIM

Hepatic fibrosis, a progressive scarring of liver tissue, is commonly caused by non-alcoholic fatty liver disease (NAFLD), which increases the risk of cardiovascular disease. The Fibrosis-4 (FIB-4) index is a non-invasive tool used to assess liver fibrosis in patients with NAFLD. Aortic valve sclerosis (AVS), a degenerative disorder characterized by thickening and calcification of valve leaflets, is prevalent in the elderly and associated with increased cardiovascular morbidity and mortality. Recent studies have suggested that AVS may also be linked to other systemic diseases such as liver fibrosis. This study aimed to investigate the relationship between the FIB-4 index and AVS in a non-alcoholic population, with the hypothesis that the FIB-4 index could serve as a potential marker for AVS.

METHOD

A total of 92 patients were included in this study. AVS was detected using transthoracic echocardiography, and patients were divided into groups according to the presence of AVS. The FIB-4 index was calculated for all patients and compared between the groups.

RESULTS

A total of 17 (18.4%) patients were diagnosed AVS. Patients with AVS had higher rates of diabetes mellitus, older age, hypertension, angiotensin-converting enzyme inhibitor use, higher systolic blood pressure (BP) and diastolic BP in the office, coronary artery disease prevalence, left atrial volume index (LAVI), left ventricular mass index (LVMI), and late diastolic peak flow velocity (A) compared to those without AVS. Moreover, AVS patients had significantly higher creatinine levels and lower estimated glomerular filtration rate. Remarkably, the FIB-4 index was significantly higher in patients with AVS. In univariate and multivariate analyses, higher systolic BP in the office (OR, 1.044; 95% CI 1.002-1.080, p = .024) and higher FIB-4 index (1.46 ± .6 vs. .91 ± .46, p < .001) were independently associated with AVS.

CONCLUSION

Our findings suggest that the FIB-4 index is associated with AVS in non-alcoholic individuals. Our results highlight the potential utility of the FIB-4 index as a non-invasive tool for identifying individuals at an increased risk of developing AVS.

Clinical Implications of Cardiac Symptoms and Electrocardiographic Abnormalities for Advanced Liver Fibrosis in Patients with Nonalcoholic Fatty Liver Disease

Background and Objectives: Advanced liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) can be a major predictor of cardiovascular disease (CVD) events and cardiac complications. However, the clinical significance of cardiac symptoms and abnormal electrocardiography (ECG) findings in patients with NAFLD associated with advanced liver fibrosis is unclear. Therefore, our study was aimed to evaluate the clinical implications based on the association between cardiac symptoms with ECG abnormalities for advanced liver fibrosis in patients with NAFLD. Materials and Methods: Of 31,795 participants who underwent health checkups, 6293 were diagnosed with NAFLD using ultrasound and inclusion criteria in a retrospective cross-sectional study. Advanced liver fibrosis was assessed based on a low NAFLD fibrosis score (NFS) and fibrosis-4 index (Fib-4) cut-off values (COVs). Cardiac data were assessed using a cardiac symptom questionnaire and 12-lead electrocardiography (ECG). Results: Among 6293 NAFLD patients with NAFLD, 304 (4.8%) experienced cardiac symptoms. NFS and Fib-4 indicated higher rates of advanced fibrosis in the cardiac-symptomatic group than in the non-symptomatic group (NFS: 7.3 vs. 4.1%; Fib-4: 7.8 vs. 3.7%; both p < 0.001). Cardiac symptoms were independently associated with advanced liver fibrosis using a step-wise-adjusted model and NFS and Fib-4 (final adjusted odds ratio (aOR), 1.40; 95% CI, 1.06-1.85; p = 0.018 for NFS; aOR, 1.67; 95%, 1.30-2.15; p < 0.001 for Fib-4). Cardiac symptoms with abnormal ECG findings independently predicted advanced liver fibrosis (aOR, 2.43; 95% CI, 1.72-3.39; p < 0.001 for NFS; aOR, 3.02; 95% CI, 2.19-4.15; p < 0.001 for Fib-4). Conclusions: Patients who have had cardiac symptoms and some ECG abnormalities may have a higher association with advanced liver fibrosis.

NAFLD in Cardiovascular Diseases: A Contributor or Comorbidity?

Nonalcoholic fatty liver disease (NAFLD) and cardiovascular diseases are both highly prevalent conditions around the world, and emerging data have shown an association between them. This review found several longitudinal and cross-sectional studies showing that NAFLD was associated with coronary artery disease, cardiac remodeling, aortic valve remodeling, mitral annulus valve calcifications, diabetic cardiomyopathy, diastolic cardiac dysfunction, arrhythmias, and stroke. Although the specific underlying mechanisms are not clear, many hypotheses have been suggested, including that metabolic syndrome might act as an upstream metabolic defect, leading to end-organ manifestations in both the heart and liver. Management of NAFLD includes weight loss through lifestyle interventions or bariatric surgery, and pharmacological interventions, often targeting comorbidities. Although there are no Food and Drug Administration-approved nonalcoholic steatohepatitis-specific therapies, several drug candidates have demonstrated effect in the improvement in fibrosis or nonalcoholic steatohepatitis resolution. Further studies are needed to assess the effect of those interventions on cardiovascular outcomes, the major cause of mortality in patients with NAFLD. In conclusion, a more comprehensive, multidisciplinary approach to diagnosis and management of patients with NAFLD and cardiovascular diseases is needed to optimize clinical outcomes.

Nonalcoholic Fatty Liver Disease and Cardiovascular Disease: a Review of Shared Cardiometabolic Risk Factors

The prevalence of nonalcoholic fatty liver disease (NAFLD) is rising. NAFLD/nonalcoholic steatohepatitis (NASH) is associated not only with hepatic morbidity and mortality but also with an increased cardiovascular risk. NAFLD and cardiovascular disease (CVD) share several risk factors, such as obesity, metabolic syndrome, hypertension, dyslipidemia, type 2 diabetes, and chronic kidney disease. This review summarizes the evidence linking cardiometabolic risk factors and NAFLD in the context of risk for CVD. The cause of NAFLD/NASH is complex, involving a range of factors from genetics to lifestyle and energy balance. Genetically driven high liver fat content does not appear to be causally associated with increased CVD risk. In contrast, metabolic dysfunction not only predisposes to liver pathology but also leads to a significantly higher CVD risk. Given that NAFLD pathophysiology is influenced by multiple factors, each patient is unique as to their risk of developing CVD and liver pathology. At the same time, the rising burden of NAFLD/NASH is closely linked with the global increase in metabolic disorders, including obesity and type 2 diabetes. Therefore, both personalized therapeutic approaches that recognize individual pathophysiology, as well as public health policies that address the root causes of cardiometabolic risk factors for NAFLD may be needed to effectively address the NAFLD/NASH epidemic.

Non-alcoholic fatty liver disease-related risk of cardiovascular disease and other cardiac complications

BACKGROUND/AIM

Non-alcoholic fatty liver disease (NAFLD) affects approximately 25% of the global adult population. The aim of this narrative review is to describe the associations between NAFLD and cardiovascular disease (CVD), arrhythmias, cardiac conduction defects, myocardial remodelling and heart failure. We also discuss the potential mechanisms that mediate or attenuate the strength of these associations, and briefly summarize the effect of treatments that both ameliorate NAFLD and decrease risk of CVD.

METHODS

Searches of PubMed were performed by the two authors using the terms listed in Appendix. We limited the timeframe to the last decade due to the vast amount of research in the field (up to April 2021) for meta-analyses, reviews and original papers. Only articles published in English were considered.

RESULTS

NAFLD is associated with an increased risk of fatal/non-fatal CVD events and other cardiac and arrhythmic complications (left ventricular hypertrophy, aortic-valve sclerosis and certain arrhythmias), independently of common CVD risk factors. There are probably several underlying mechanisms, including hepatic/systemic insulin resistance, atherogenic dyslipidaemia, hypertension and pro-atherogenic, pro-coagulant and pro-inflammatory mediators released from the steatotic/inflamed liver that may be involved. Some genetic polymorphisms, such as PNPLA3 (rs738409 C>G) and TM6SF2 (rs58542926 C>T), may worsen the liver disease, but also attenuate the strength of the association between NAFLD and CVD, possibly via their effects on lipoprotein metabolism. Of the currently tested drugs for treating NAFLD that also benefit the vasculature, pioglitazone and GLP-1 receptor agonists are the most promising.

CONCLUSIONS

The complex interplay between the liver and cardiometabolic risk factors contributes to CVD, arrhythmias and cardiac disease in NAFLD. There is an urgent need for a multidisciplinary approach to manage both liver disease and cardiometabolic risk, and to test the cardiovascular and cardiac effects of new drugs for NAFLD.

A clinical overview of non-alcoholic fatty liver disease: A guide to diagnosis, the clinical features, and complications-What the non-specialist needs to know

Non-alcoholic fatty liver disease (NAFLD) has a rapidly rising prevalence worldwide and is the most common cause of liver disease in developed countries. In this article, we discuss the spectrum of disease of NAFLD with a focus on the earlier spectrum of the disease that is commonly encountered by non-specialists, as well as the hepatic and extra-hepatic associations of the disease. We discuss in detail the two common presentations of NAFLD, incidentally detected hepatic steatosis and asymptomatic raised liver enzymes, and provide an algorithm for management and continued to follow up for these patients. Considerations for the management of cardiovascular comorbidities in these patients are also discussed. Finally, we cover the topic of screening for NAFLD in high-risk populations.

Review article: non-alcoholic fatty liver disease and cardiovascular diseases: associations and treatment considerations

BACKGROUND

There are increasing data on the association between non-alcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVD).

AIM

To summarise evidence on the association between NAFLD and CVD in the clinical setting and provide potential therapeutic implications.

METHODS

We searched PubMed. Evidence was primarily derived from meta-analyses. and then, if data were insufficient, from clinical trials, and then from observational studies.

RESULTS

NAFLD has been linked to arterial hypertension, arterial stiffness, atherosclerosis, coronary artery disease, atrial fibrillation and aortic valvular sclerosis. Advanced liver fibrosis is a crucial prognostic factor for end-stage liver disease and for cardiovascular and overall mortality. Weight loss through lifestyle modifications (diet and exercise) remains the cornerstone of the management of both NAFLD and CVD, but is difficult to achieve and possibly more difficult to sustain long term. Therefore, pharmacological management of NAFLD seems to be important, although no licenced medication currently exists. Pioglitazone, proposed for non-alcoholic steatohepatitis (NASH) by most guidelines, increases weight and should be avoided in congestive heart failure. Statins should not be avoided in NAFLD patients at risk for CVD. Glucagon-like peptide 1 receptor agonists and sodium-glucose cotransporter-2 inhibitors, two classes of anti-diabetic drugs, have shown promising results in NAFLD and CVD, but more studies with hard end points are needed. Obeticholic acid, a promising medication for NASH under investigation, should be carefully considered, owing to its adverse effect on lipid profile.

CONCLUSIONS

NAFLD is associated with CVD, which may have certain clinical and therapeutic implications.

Urantide decreases hepatic steatosis in rats with experimental atherosclerosis via the MAPK/Erk/JNK pathway

Hepatic steatosis, an indicator of atherosclerosis (AS), is always accompanied by inflammatory responses and disturbances in lipid metabolism. The present study investigated the protective effect of urantide, a urotensin II (UII) receptor antagonist, on the liver of rats with AS with hepatic steatosis by regulating the MAPK pathway. AS was induced in rats via an intraperitoneal injection of vitamin D3 and the administration of a high‑fat diet. Urantide treatment was then administered to the rats. Pathology, liver index, lipid levels and liver function were measured to determine liver injury. The expression levels of UII and G protein‑coupled receptor 14 (GPR14) were determined using immunohistochemistry, reverse transcription‑quantitative PCR and western blotting. The expression levels of MAPK‑related proteins in hepatocytes from each group were quantified using western blotting and immunofluorescence staining. Rats with AS had typical pathological changes associated with AS and hepatic steatosis, which were significantly improved by urantide treatment. Blood lipid levels, body weight, liver index and liver function were recovered in rats with AS after urantide treatment. Urantide downregulated the expression levels of UII and GPR14 in the livers of rats with AS; concurrently, the phosphorylation of Erk1/2 and JNK was significantly decreased. Moreover, no significant changes were observed in the phosphorylation of p38 MAPK in AS rat livers. In conclusion, urantide inhibits the activation of Erk1/2 and JNK by blocking the binding of UII and GPR14, thereby alleviating hepatic steatosis in rats with AS, ultimately restoring lipid metabolism in the liver and alleviating AS lesions.

NAFLD, and cardiovascular and cardiac diseases: Factors influencing risk, prediction and treatment

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD), affecting up to around 30% of the world's adult population, causes considerable liver-related and extrahepatic morbidity and mortality. Strong evidence indicates that NAFLD (especially its more severe forms) is associated with a greater risk of all-cause mortality, and the predominant cause of mortality in this patient population is cardiovascular disease (CVD). This narrative review aims to discuss the strong association between NAFLD and increased risk of cardiovascular, cardiac and arrhythmic complications. Also discussed are the putative mechanisms linking NAFLD to CVD and other cardiac/arrhythmic complications, with a brief summary of CVD risk prediction/stratification and management of the increased CVD risk observed in patients with NAFLD.

RESULTS

NAFLD is associated with an increased risk of CVD events and other cardiac complications (left ventricular hypertrophy, valvular calcification, certain arrhythmias) independently of traditional CVD risk factors. The magnitude of risk of CVD and other cardiac/arrhythmic complications parallels the severity of NAFLD (especially liver fibrosis severity). There are most likely multiple underlying mechanisms through which NAFLD may increase risk of CVD and cardiac/arrhythmic complications. Indeed, NAFLD exacerbates hepatic and systemic insulin resistance, promotes atherogenic dyslipidaemia, induces hypertension, and triggers synthesis of proatherogenic, procoagulant and proinflammatory mediators that may contribute to the development of CVD and other cardiac/arrhythmic complications.

CONCLUSION

Careful assessment of CVD risk is mandatory in patients with NAFLD for primary prevention of CVD, together with pharmacological treatment for coexisting CVD risk factors.

Plasma phospholipid dysregulation in patients with cystathionine-β synthase deficiency

BACKGROUND & AIMS

Patients with cystathionine β-synthase deficiency (CBSD) exhibit high circulating levels of homocysteine and enhanced lipid peroxidation. We have characterized the plasma lipidome in CBSD patients and related lipid abnormalities with reactions underlying enhanced homocysteine levels.

METHODS AND RESULTS

Using an ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry method, plasma lipids were determined with an untargeted lipidomics approach in 11 CBSD patients and 11 matched healthy subjects (CTRL). Compared to CTRL, CBSD patients had a higher medium and long-chain polyunsaturated fatty acids (PUFA) content in phosphatidylethanolamine (PE) and lysophosphatidylethanolamine (LPE) species (p < 0.02), and depletion of phosphatidylcholine (PC; p = 0.02) and of lysophosphatidylcholine (LPC; p = 0.003) species containing docosahexaenoic acid (DHA), suggesting impaired phosphatidylethanolamine-N-methyltransferase (PEMT) activity. PEMT converts PE into PC using methyl group by S-adenosylmethionine (SAM) thus converted in S-adenosylhomocysteine (SAH). Whole blood SAM and SAH concentrations by liquid chromatography tandem mass spectrometry were 1.4-fold (p = 0.015) and 5.3-fold (p = 0.003) higher in CBSD patients than in CTRL. A positive correlation between SAM/SAH and PC/PE ratios (r = 0.520; p = 0.019) was found.

CONCLUSIONS

A novel biochemical abnormality in CBSD patients consisting in depletion of PC and LPC species containing DHA and accumulation of PUFA in PE and LPE species is revealed by this lipidomic approach. Changes in plasma SAM and SAH concentrations are associated with such phospholipid dysregulation. Given the key role of DHA in thrombosis prevention, depletion of PC species containing DHA in CBSD patients provides a new direction to understand the poor cardiovascular outcome of patients with homocystinuria.

Nonalcoholic fatty liver disease and cardiovascular disease phenotypes

Nonalcoholic fatty liver disease is increasingly recognized as a major global health problem. Intertwined with diabetes, metabolic syndrome, and obesity, nonalcoholic fatty liver disease embraces a spectrum of liver conditions spanning from steatosis to inflammation, fibrosis, and liver failure. Compared with the general population, the prevalence of cardiovascular disease is higher among nonalcoholic fatty liver disease patients, in whom comprehensive cardiovascular risk assessment is highly desirable. Preclinical effects of nonalcoholic fatty liver disease on the heart include both metabolic and structural changes eventually preceding overt myocardial dysfunction. Particularly, nonalcoholic fatty liver disease is associated with enhanced atherosclerosis, heart muscle disease, valvular heart disease, and arrhythmias, with endothelial dysfunction, inflammation, metabolic dysregulation, and oxidative stress playing in the background. In this topical review, we aimed to summarize current evidence on the epidemiology of nonalcoholic fatty liver disease, discuss the pathophysiological links between nonalcoholic fatty liver disease and cardiovascular disease, illustrate nonalcoholic fatty liver disease-related cardiovascular phenotypes, and finally provide a glimpse on the relationship between nonalcoholic fatty liver disease and cardiac steatosis, mitochondrial (dys)function, and cardiovascular autonomic dysfunction.

Cardiovascular morbidity and mortality in patients with aortic valve sclerosis: A systematic review and meta-analysis

AIMS

The association between aortic valve sclerosis (AVSc) and cardiovascular (CV) events is not consistent among different studies. We have performed a meta-analysis evaluating the association between AVSc and fatal and/or non-fatal CV and cerebrovascular events.

METHODS AND RESULTS

A systematic search was performed in the electronic databases (PubMed, Web of Science, Scopus, EMBASE). Studies evaluating coronary artery disease (CAD), stroke and CV mortality in AVSc patients and controls were included. Differences among cases and controls were expressed as Odds Ratio (OR) with pertinent 95% Confidence Intervals (CI). Thirty-one studies on 10,537 AVSc patients and 25,005 controls were included in the final analysis. The absolute risk of CAD was 45.8% (95% CI: 32.9-59.3) in AVSc patients and 29.4% (95% CI: 21.8-38.5) in controls with an OR of 2.02 (95% CI: 1.67-2.44) and an attributable risk of 35.8%. Moreover, stroke was reported in 11.8% (95% CI: 4.4-27.7) of AVSc patients and 7.9% (95% CI: 2.5-22.7) of controls (OR: 1.41, 95% CI: 1.16-1.71) with an attributable risk of 33.0%. CV mortality was 6.2% (95% CI: 2.7-13.5) in AVSc patients and 2.0% (95% CI: 0.5-7.9) in controls (OR: 2.70, 95% CI: 1.45-5.01), with an attributable risk of 67.7%. Results were confirmed when pooling together ORs for CAD, stroke and CV mortality obtained by means of multivariate analysis.

CONCLUSIONS

AVSc is associated with CAD, stroke and CV mortality. Taken together, these data suggest that patients with AVSc may benefit from a stricter CV risk monitoring and that AVSc screening may be included in the frame of CV risk stratification protocols.

Markers of subclinical atherosclerosis in patients with aortic valve sclerosis: A meta-analysis of literature studies

OBJECTIVE

Growing evidence suggested an association between aortic valve sclerosis (AVSc) and cardiovascular (CV) events. However, little is known about the association of AVSc with major markers of subclinical atherosclerosis. We performed a meta-analysis of literature studies to address this issue.

METHODS

Studies on the relationship between AVSc and common carotid artery intima-media thickness (IMT), prevalence of carotid plaques (CPs), flow-mediated dilation (FMD), aortic pulse wave velocity (PWV) and augmentation index (AIx) were systematically searched in electronic databases. Thirteen studies enrolling 1086 AVSc patients and 2124 controls were included.

RESULTS

Compared to controls, AVSc patients showed higher IMT (MD: 0.32mm; 95%CI: 0.07, 0.58; p=0.014), and higher prevalence of CPs (OR: 4.06; 95%CI: 2.38, 6.93; p<0.001). Moreover, lower FMD (MD: -4.48%; 95%CI: -7.23, -1.74; p=0.001) and higher PWV (MD: 0.96%; 95%CI: 0.11, 1.81; p=0.027) were found in AVSc subjects than in controls, with no differences in AIx (MD: 0.76%; 95%CI: -0.97, 2.49; p=0.389). In meta-regression analyses, body mass index and triglyceride levels have an impact on the difference in IMT between cases and controls, while male gender and smoking habit were associated with the difference in the prevalence of CPs between the two groups.

CONCLUSIONS

AVSc is significantly associated with altered markers of subclinical atherosclerosis, thus supporting the concept that AVSc and atherosclerosis share common etiopathological mechanism and/or risk factors.