Association of serum transaminases with short- and long-term outcomes in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Liver function tests usually comprise ALT, AST, ALP, GGT, other nonenzymatic proteins (e.g., albumin), and heme metabolites, such as bilirubin. Among these markers, AST and ALT are often elevated in patients with STEMI [17]. Serum ALT is predominantly found in the liver. AST is mainly derived from liver and, hence, also considered as a marker of liver function; however, a significant portion of AST is derived from the heart and other tissues. Nevertheless, it remains unclear whether ALT or AST provide any long- or short-term independent prognostic value in STEMI patients who underwent PCI and whether ALT and AST levels are associated with any other risk factors.

To our knowledge, this is the first prospective study evaluating the association between ALT and AST and short- and long-term all-cause mortality in STEMI patients who underwent PCI. We demonstrated in the Chinese Han ethnic group that AST and ALT levels on admission were significant correlated with Killip classification, pre-TIMI flow, infarct-related coronary artery, and cardiac troponin I. Serum transaminases ?95th percentage were associated with a significantly increased incidence of short- and long-term all-cause mortality.

Recent studies investigating the relationship between ALT and AST with mortality have yielded conflicting results. A large national population-based cohort study conducted in the United States showed a lack of association between overall or cardiovascular-disease (CVD) mortality with ALT [18]. However, a similar study of a population-based cohort of Caucasian persons aged 55 years or older found AST and ALT are associated with all-cause mortality [19]. Furthermore, a recent meta-analysis study with aggregate data on over 9.24 million participants and 242,953 instances of all-cause mortality found a comparatively moderate association of AST with all-cause mortality and geographical variations in the association of ALT with all-cause mortality risk in general populations [7]. Interestingly, other studies have found elevation of common markers, including ALT and AST, in patients with heart failure and CVD with liver injury resulting from ischemia or congestion [20–23]. These results further confirm the association between ALT/AST and mortality risk. Considering that liver enzymes are routine parameters of liver function assessed in STEMI patients before PCI, we investigated the association between ALT/AST and all-cause mortality in the Chinese Han ethnic group.

Notably, increased ALT levels are found in STEMI patients with acute liver injury [24–26]. Cardiac disorders contribute to the liver injury [2, 4, 27, 28]. We excluded patients with chronic hepatitis to exclude liver injury derived from hepatic disorders. The infarct-related artery only strategy for patients with multivessel arteries disease presenting with STEMI in our center minimize potential impact of different strategies of complete vs. culprit-only revascularization [29]. The primary infarct-related coronary artery in patients with ALT???95th percentage was LAD. Our findings support LAD occlusion as the factor most closely associated with left ventricular ejection fraction and with measures of left ventricular regional hypofunction, especially caused by proximal LAD [30, 31].

The liver has high metabolic activity and perfusion rate, and acute circulatory changes, such as cardiogenic shock resulting from an acute myocardial infarction, directly influence hepatic blood flow [32–34]. Every 10 mmHg drop in arterial pressure decreases the hepatic blood flow by approximately 10% [33, 35]. Circulatory failure triggers compensatory mechanisms in the liver by increasing oxygen extraction from the blood up to 95%, which results in hepatocellular dysfunction and elevation of AST/ALT [36]. The assessment for the presence and severity of circulatory failure were assessed by the Killip classification through physical examination, which showed the serum level of ALT and AST were high along with the increasing of the grade of Killip classification. Because hypoxic injury to the liver is a reversible subclinical condition accounting for over 50% of dramatic serum aminotransferase activity identified in hospital admissions [37], our results demonstrating the predictive value of ALT and AST for short-term, but not long-term, all-cause mortality were not surprising. The influences of genetics on the ethnic and environmental factors, the dosage of prescription drugs, adherence to therapy and cardiac rehabilitation all had important roles on the long-term overall cardiovascular risk. Unless for ALT and AST levels ?95th percentage, the all-cause mortality at 1 month and 2 years post-procedure both significantly increased.