Macrophage-inhibitory cytokine-1 (mic-1) in differential diagnosis of dyspnea-A pilot study

Background: Macrophage inhibitory cytokine-1 (MIC-1) has recently been associated with markers of heart function. Aim: This study sought to verify the relationship between markers of heart function (New York Heart Association classification (NYHA)): left ventricle ejection fraction (LVEF), N terminal prohormone of natriuretic peptide B type (NT-proBNP) and MIC-1. Furthermore, the assessment of the usefulness of these markers for differential diagnosis of the myocardial form of dyspnea was explored. Methods: 124 patients (65 women and 59 men) were examined for dyspnea without signs of acute coronary syndrome. All patients underwent echocardiography (calculation of left ventricle ejection fraction-LVEF), and serum NT-proBNP, proguanylin as well as MIC-1 were determined. 21 healthy individuals were defined as the control group. Results and discussion: Patients were divided into two groups: A-individuals with non-cardiogenic form of dyspnea, n = 77 and B individuals with cardiogenic ethiology of dyspnea, n = 47. Significant differences between MIC-1 values in individuals with cardiogenic dyspnea (median 2189.6 ng/L) and non-cardiogenic dyspnea (median 232.1 ng/L) were shown. MIC-1 correlated with age, proguanylin, NT-proBNP and negatively with LVEF (P<0.05). The median values of MIC-1 were closely associated with the NYHA classification (P<0.05). Division of the group under study according to the cause of dyspnea revealed a significant difference in MIC-1 (P<0.01). The cut-off of MIC-1>444.5 ng/L showed 100% sensitivity and 89.3% specificity for diagnosing cardiogenic dyspnea. After adjustment for age, gender and NT-proBNP, MIC-1 levels were significantly associated with the cardiogenic type of dyspnea (P<0.05). We also tested the difference in MIC-1 level among the subgroup with the cardiac form of dyspnea (10 individuals suffered from hypertension and 37 patients had no sign of hypertension). Individuals with and without hypertension had no significant difference in MIC-1 level. Conclusion: MIC-1 is a new diagnostic marker in the differential diagnosis of dyspnea. (C) 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.