Biomarkers of cardiohepatic syndrome in the cardiac intensive care unit

Abstract Introduction Non-cardiovascular end-organ dysfunction is an important determinant of outcomes in cardiac intensive care unit (CICU) patients. We examined the association between in-hospital mortality with the severity and extent of admission liver function test (LFT) abnormalities in a heterogeneous CICU population. Purpose We hypothesized that a greater severity or extent of LFT abnormalities would be associated with higher in-hospital mortality. Methods We included consecutive unique adult CICU patients with available data for one or more of the admission LFT values of interest. Admission laboratory values were defined as those closest to CICU admission. We used the NIH Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 to categorize the severity of each LFT abnormality from Grade 0 (normal) to Grade 4 (life-threatening). We defined the extent of LFT abnormality as the number of individual LFTs meeting criteria for CTCAE Grade 1 or greater. The primary outcome of interest was all-cause in-hospital mortality. Odds ratio (OR) and 95% confidence interval (CI) values for in-hospital mortality were estimated using logistic regression, before and after multivariable adjustment. Results Of 12,428 unique CICU patients, 5,144 were excluded due to a lack of available data for any admission LFT values. The remaining 7,284 patients comprised the final study population. Among patients with available data for each individual LFT, abnormal values were present in: AST, 2,743/5,733 (47.8%); ALT 1,576/5,512 (28.6%); ALK 611/3,684 (16.6%); and TB 898/5,155 (17.4%). A total of 864 (11.9%) patients died during hospitalization. In-hospital mortality was higher for patients with one or more LFTs meeting criteria for CTCAE Grade 1 or greater (17.9% vs. 6.4%, adjusted OR 1.54 [1.27-1.86], p <0.001). A stepwise increase in in-hospital mortality was observed with increasing CTCAE grade, both overall (adjusted OR 1.25 per each higher CTCAE grade [1.16-1.34], p <0.001); (Figure 1A), and for each individual LFT (Figure 1B). Conclusion Cardiohepatic syndrome is an important predictor of prognosis in CICU patients, as the extent and severity of LFT abnormalities are strongly associated with in-hospital mortality. This is the first large-scale study to examine the association between the magnitude of hepatic biomarker derangement with in-hospital mortality in unselected CICU patients. Patients with markedly elevated LFT values exhibited the highest risk of in-hospital mortality. This analysis advocates for the inclusion of commonly obtained LFTs in future risk-prediction tools for enhanced prognostication.