Clinical outcomes after coronary angiography in nonalcoholic fatty liver disease
Authors: Savas Sarikaya, Yasar Turan, Mehmet Celikbilek
Journal: Hepatology (2016)

We read with great interest the article recently published in Hepatology by Wong et al.,1 showing that the presence of nonalcoholic fatty liver disease (NAFLD) is associated with coronary artery stenosis and the need for coronary intervention, but not with increased mortality or cardiovascular complications, in NAFLD patients with clinical indications for coronary angiography. They suggested that the data do not support NAFLD screening in this patient group but that studies with a longer follow-up are needed. In their study, NAFLD patients had more cardiometabolic risk factors, including higher body mass index, fasting plasma glucose levels, and triglyceride levels and lower high-density lipoprotein cholesterol levels; and they were more likely to be men and to have type 2 diabetes mellitus and hypertension. NAFLD patients had more severe coronary artery disease and underwent more coronary interventions, including percutaneous coronary intervention (PCI) and coronary artery bypass grafting. Despite all of this, these patients still had fewer cardiovascular events and lower mortality than patients without NAFLD. These findings are contrary to expectations. One or more explanations might account for these unexpected results. One is that NAFLD patients had more risk factors for cardiovascular disorders; as a result, they may have been followed closely and received more aggressive therapy than patients without NAFLD, which might affect the prognosis. Second, as Wong et al. mentioned, longer follow-up is needed to observe cardiovascular events and mortality. In addition, angiography alone cannot accurately determine the hemodynamic significance of coronary lesions. A lesion may appear significant on coronary angiography but may not have functional significance. In addition to the degree of stenosis in the coronary artery, the presence of ischemia is important when considering coronary intervention, and the presence of ischemia is associated with poor cardiovascular outcomes.2-4 Previous randomized controlled trials in patients with stable coronary artery disease, comparing PCI with medical therapy without assessing the presence of ischemia, have shown no differences in composite death and myocardial infarction or in mortality alone.3, 4 Recently, Gada et al.5 reviewed three randomized controlled trials that compared optimal medical therapy and PCI in stable coronary artery patients with objective ischemia, including noninvasive stress imaging or abnormal fractional flow reserve, enrolling a total of 1,557 patients followed for an average of 3.0 years. They showed that PCI was associated with lower mortality in patients with ischemia. Gada et al. had no data on ischemia detected by noninvasive stress imaging or abnormal fractional flow reserve. Therefore, NAFLD patients may be overestimated or underestimated regarding coronary intervention, which might affect cardiovascular outcomes. The presence of ischemia should be considered when performing clinical outcome studies using coronary angiography and PCI in NAFLD patients. Savas Sarikaya, M.D.1 Yasar Turan, M.D.1 Mehmet Celikbilek, M.D.2 1Department of Cardiology 2Department of Gastroenterology Bozok University Yozgat, Turkey