Plasma Indoleamine 2,3-dioxygenase is predictive of left ventricular remodeling after myocardial infarction.

Acute myocardial infarction (MI) is associated with an inflammatory response that may lead and/or worsen adverse left ventricular (LV) remodeling. Among inflammation markers is Indoleamine 2,3-dioxygenase (IDO), which production is induced upon inflammation. IDO catalyzes the transformation of tryptophane into kynurenine. We tested plasma IDO activity as a predictor of LV remodeling post-MI. The PREGICA cohort recruited prospectively patients with first MI. Blood samples, 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 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%. Among the 292 patients studied (mean age 57 y, mean necrosis size 26% on MRI), the median increase in EDLVV was 16.7% and 137 (47%) were classified as remodelers. 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 (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, plasma levels of NT-proBNP, ST2, Galectin 3 or CRP at day 4 were poorly predictive. In multivariate analysis including other predictive variables at day 4 (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]). IDO activity appears as a promising biomarker for the prediction of LV remodeling after MI. Its specific role in post-MI remodeling pathways requires further investigation. [ABSTRACT FROM AUTHOR]