By Michael H. Crawford, MD, Editor

SYNOPSIS: A prospective, multicentered, observational study of patients admitted with cardiogenic shock showed that a > 20% rise in alanine aminotransferase in the first 24 hours is associated highly and independently with 90-day mortality.

SOURCE: Jäntti T, Tarvasmäki T, Harjola VP, et al. Frequency and prognostic significance of abnormal liver function tests in patients with cardiogenic shock. Am J Cardiol 2017;120:1090-1097.

Abnormal liver function tests (LFTs) are known to be of prognostic valve in acute and chronic heart failure. Cardiogenic shock (CGS) is the most profound form of acute heart failure, yet there are little data on the value of LFTs in CGS. Investigators from the European CardShock study, a multinational, prospective, observational study of 178 patients admitted for CGS between 2010 and 2012 from nine tertiary hospitals in eight European countries, assessed the prevalence of LFT abnormalities, their serial changes, and effects on outcome. CGS inclusion criteria were systolic blood pressure < 90 mmHg and signs of hypoperfusion after an adequate fluid challenge. Exclusion criteria were significant arrhythmias or shock after surgery. The evaluation and treatment were at the discretion of the local physicians. Blood samples were obtained serially at 12-hour intervals. An increase in LFT values was defined as a > 20% rise from baseline in the first 24 hours. If the highest LFT value was in the normal range, it was considered not increased. The primary endpoint was 90-day all-cause mortality. The mean age of the patients was 66 years. Seventy-four percent were men. Most exhibited an acute coronary syndrome (80%), and the 90-day mortality was 42%.

Among the LFTs, alanine aminotransferase (ALT) was abnormal most frequently, was elevated at baseline in 58% of patients, and was abnormal at all time points more commonly in non-survivors. An increase in ALT > 20% in the first 24 hours was observed in 24% of patients and was associated with an increased mortality compared to those with stable or falling levels (70% vs. 28%; P < 0.001). Multivariate regression analysis showed that an ALT increase > 20% was associated independently with 90-day mortality (hazard ratio, 3.16; 95% confidence interval, 1.72-5.82; P < 0.001). An ALT > 20% increase was associated with oliguria, left ventricular ejection fraction, and peak troponin and lactate levels, but not NT-proBNP. The authors concluded that an increase in ALT was observed in about one-quarter of patients in the first 24 hours after admission for CGS and was associated independently with 90-day mortality.

COMMENTARY

The most recent guidelines for the management of CGS recommend daily LFTs and lactate every one to four hours.1 This study suggests that among the LFTs, ALT alone should be measured at least at admission, 12 hours, and 24 hours later. How ALT would compare to lactate levels was not studied in this analysis, but it was noteworthy that in a multivariate model that included lactate, a > 20% rise in ALT was a strong, independent predictor of 90-day mortality. A > 20% rise is rather modest but is powerfully associated with other signs of persistent hypoperfusion. Other LFTs also may be abnormal but are not predictive of early mortality and need not be followed frequently. Although elevated baseline ALT levels were frequent (58%) and more common in non-survivors, they did not predict early mortality. This is probably because baseline ALT may be elevated because of other causes such as alcohol use or chronic right heart failure. There were some limitations to this study. It was rather small, and although all 178 patients underwent baseline LFTs, only 154 had samples at 12 and 24 hours. Some patients died in < 24 hours. Hemodynamic measurements of the pulmonary circulation were performed in a minority of patients since this is not a uniform recommendation in CGS patients but rather a more selected one. Since this was an observational study, it is impossible to consider all potential confounders. The main strength of the study was that it was the first to systematically evaluate early serial LFTs in CGS patients. The authors recommended that ALT should be performed serially in the first 24 hours a patient receives treatment for CGS as a rising level suggests that tissue perfusion is not adequate for survival.

REFERENCE

  1. van Diepen S, Katz JN, Albert NM, et al. Contemporary management of cardiogenic shock: A scientific statement from the American Heart Association. Circulation 2017;136:e232-e268.