P5444Plasma Indoleamine 2,3-dioxygenase is highly predictive of cardiac remodeling after myocardial infarction

Background Acute myocardial infarction (MI) is associated with a strong inflammatory response resulting from the cardiac insult. On the other hand, such an inflammation may lead and/or worsen adverse left ventricular (LV) remodeling after MI. Among the markers of inflammation is Indoleamine 2,3-dioxygenase (IDO), which production is induced upon inflammation. IDO catalyzes the transformation of tryptophane into kynurenine. Purpose We tested plasma IDO activity as a predictor of LV remodeling post-MI. Methods The PREGICA cohort recruited prospectively patients who were admitted because of first acute myocardial infarction. Blood samples were collected on admission, at day 4 and at day 6. Echocardiography and cardiac MRI were obtained at day 4 and at 6 months. To be included, the number of akinetic LV wall segments had to be ≥3 on 17 at day 4. IDO activity was the ratio between kynurenine and tryptophane measured by high pressure liquid chromatography coupled with fluorimetric detection. Remodelers were identified as patients with a variation of end-diastolic left ventricular volume (EDLVV) between day 4 and 6 months post-MI >20%. Results Among the 292 patients studied (mean age 57y, mean necrosis size 26% on MRI), the median increase in EDLVV was 16.7% and 137 (47%) were classified as remodelers. On admission as well as at day 4, IDO activity was significantly higher in remodelers (8.2±4.2% vs 5.3±2.5% and 8.7±5.7% vs 5.6±4.4%, p<0.001) and remained higher at 6 months post-MI. IDO activity at day 4 was highly predictive of LV remodeling (Figure): AUC = 87% [95% CI 83–91%]; IDO threshold of 5.8% resulted in specificity = 81%, sensitivity = 89%, negative predictive value = 89%, positive predictive value = 80%. In contrast, blood levels of NTproBNP, ST2, Galectin 3 or CRP at day 4 were poorly predictive. In multivariate analysis including other predictive variables at day4 (primary angioplasty, EDLVV, LVEF, necrosis size), increase in IDO activity was significantly associated with LV remodeling (OR 1.21 [95% CI 1.11–1.33]. Conclusions IDO activity appears as a promising biomarker for the prediction of LV remodeling after MI. Its specific role in postMI remodeling pathways requires further investigation. Acknowledgement/Funding PHRC national