Mri characterIzation of Troponin Elevation After Cardiac Surgery

Characterization of Postoperative Myocardial Lesions by Cardiac MRI and Anatomo-biological Correlations With Serum Troponin in Cardiac Surgery.

Cardiac surgery under cardiopulmonary bypass (CPB) induces myocardial ischemia-reperfusion injury. This myocardial attack is a well-identified independent prognostic factor of postoperative morbidity and mortality. The quantification of these myocardial lesions by the postoperative plasma release of troponin has proven its diagnostic and prognostic value.

Cardiac magnetic resonance imaging (MRI) can accurately measure and characterize the size of myocardial lesions. These lesions are associated with a poor prognosis. MRI can also characterize myocardial edema secondary to ischemia-reperfusion which has not yet been studied in the context of CPB. It is therefore necessary, in a mechanistic approach, to quantify the respective share of necrosis, edema and reperfusion lesions during cardiac surgery under CPB in order to better understand these phenomena and to propose effective strategies for the prevention of these myocardial lesions.the relationship between the postoperative release of troponin and the amount of myocardial necrosis and edema measured by cardiac MRI will be assessed.The hypothesis is to demonstrate a positive correlation between imaging and biology in order to better understand the perioperative myocardial lesion processes.

This is an interventional study prospective, exploratory, in cardiac imaging, non-comparative and single-center, including 30 patients.

Inclusion Criteria:

• Age ≥ 18 years old
• Aortic valve surgery with CEC: aortic valve replacement, Bentall, Tirone-David, Wheat with foreseeable clamping time of at least 40 minutes.
• Informed consent signed

Exclusion Criteria:

• Emergency surgery
• Other unconventional heart surgery
• Aorto-coronary bypass associated with surgery
• History of myocardial infarction or severe coronary artery disease, non-valvular hypertrophic cardiomyopathy (MHC) (primary MHC type, Amyloidosis) and myocarditis
• Preoperative alteration of systolic function of the left ventricle (LVEF <40%)
• Presence of a contraindication to cardiac MRI (claustrophobia, pacemaker or cardiac defibrillator, metallic body, hypersensitivity to gadolinium)
• Patients with a glomerular filtration rate (GFR) <30 ml / min
• Patients with permanent atrial fibrillation (ACFA) cardiac arrhythmia
• Patients treated with anthracyclines
• Pregnant and / or lactating woman
• Patient under legal protection
• Patient not benefiting from a social security system
• Patient participating in another clinical study that may interfere with the results of this study.