Non-alcoholic fatty liver disease: a new challenge for cardiologists

Abstract: The prevalence of non-alcoholic fatty liver disease (NAFLD) ranges from 17% to 33% in the general population. It is frequently associated with obesity (60-90%), dyslipidemia (27-92%), diabetes (28-55%) and arterial hypertension (22%); in the presence of the metabolic syndrome, its incidence is 2-fold higher. NAFLD can be considered as an early mediator of the atherosclerotic process with which it shares some pathogenetic mechanisms (insulin resistance, oxidative stress, endothelial dysfunction, inflammatory activation). Patients with NAFLD are usually asymptomatic, high values of liver enzyme tests being the most common finding. Although liver biopsy is the current gold standard for diagnosis of NAFLD, it is not a practical screening tool given the cost, time-consuming nature and potential morbidity of this procedure. Ultrasound is a relatively inexpensive technique of liver imaging. Patients with NAFLD exhibit a higher mortality rate than the general population. The most frequent causes of death are represented by liver-related diseases, malignant neoplasms and cardiovascular disease, the latter being as frequent as malignant neoplasms. Data on cardiac abnormalities in patients with NAFLD are scarce. Abnormalities in left ventricular geometry and diastolic function have been described in patients with NAFLD as well as a more severe coronary artery disease characterized by vulnerable plaques, though observed in small cohort studies. According to the available evidence, NAFLD should be taken into consideration by cardiologists because its identification allows a better risk stratification in both primary and secondary prevention. Its correlation with coronary artery disease strongly suggests that NAFLD plays a proatherogenic role per se, in addition to the well known atherosclerotic risk factors. The finding of increased fatty liver content should prompt to assess the coexistence of other risk factors as well as to tailor the appropriate therapeutic regimen in order to reduce fatty liver content.