BIOMEDICAL JOURNAL OF PIROGOV RNRMU (MOSCOW, RUSSIA)
Evaluation of cardiac MRI efficacy in the diagnosis of hibernating myocardium
The efficacy of cardiac MRI in the diagnosis of hibernating myocardium remains understudied. The existing body of evidence on this matter comes mainly from observational studies carried out in heterogenous (in terms of cardiac pathology) cohorts of patients, which complicates the interpretation of the results. The aim of our study was to evaluate the efficacy of cardiac imaging techniques in 144 patients with a history of myocardial infarction, multivessel coronary artery disease and a low ejection fraction of the left ventricle. All participants underwent stress echocardiography and cardiac MRI examinations. The following parameters were factored into: a) the number of identified segments with abnormal myocardial contractility; b) the transmurality index (scar thickness); c) the volume of the viable myocardium relative to its total mass. The study revealed that on average there were 2.72 ± 0.82 segments with contractile dysfunction per patient. Cardiac MRI was able to detect significantly more hibernating segments than stress echocardiography. On average, the difference in the number of detected segments was 36 (56; 86) at 95% CI and р < 0.01. We established that as the transmurality index increases, the number of hypokinetic segments decreases (r = –0.78; р = 0.0314) while the number of akinetic segments (r = –0.84; р = 0.0282) goes up. This needs to be accounted for when selecting a treatment strategy for such patients. We conclude that cardiac MRI is a more effective and sensitive diagnostic technique in patients with hibernating myocardium that allows detecting significantly more cardiac segments with contractile dysfunction than stress echocardiography. Delayed contrast enhancement is instrumental in estimating the thickness and extent of cardiac fibrosis, the parameters that should be accounted for when deciding on the treatment strategy in such patients.
Keywords: hibernating myocardium, cardiac MRI, dobutamine stress echocardiography