Importance of Myocardial Fibrosis in Functional Mitral Regurgitation: From Outcomes to Decision-Making

Role of Ferroptosis in Fibrosis Diseases

Ferroptosis is a pervasive non-apoptotic mode of cell death that is different from autophagy or necrosis. It is mainly caused by an imbalance between the production and degradation of lipid reactive oxygen species in cells. Several metabolic pathways and biochemical processes, such as amino acid and lipid metabolism, iron handling, and mitochondrial respiration, affect and regulate cell sensitivity to peroxidation and ferroptosis. Organ fibrosis, a pathological manifestation of several etiological conditions, leads to chronic tissue injury and is characterized by excessive deposition of extracellular matrix components. Excessive tissue fibrosis can have diverse pathophysiological effects on several organ systems, eventually causing organ dysfunction and failure. The current manuscript provides a review that illustrates the link between ferroptosis and organ fibrosis and to better understand the underlying mechanisms. It provides novel potential therapeutic approaches and targets for fibrosis diseases.

Echocardiography vs. CMR in the Quantification of Chronic Mitral Regurgitation: A Happy Marriage or Stormy Divorce?

Quantification of chronic mitral regurgitation (MR) is essential to guide patients’ clinical management and define the need and appropriate timing for mitral valve surgery. Echocardiography represents the first-line imaging modality to assess MR and requires an integrative approach based on qualitative, semiquantitative, and quantitative parameters. Of note, quantitative parameters, such as the echocardiographic effective regurgitant orifice area, regurgitant volume (RegV), and regurgitant fraction (RegF), are considered the most reliable indicators of MR severity. In contrast, cardiac magnetic resonance (CMR) has demonstrated high accuracy and good reproducibility in quantifying MR, especially in cases with secondary MR; nonholosystolic, eccentric, and multiple jets; or noncircular regurgitant orifices, where quantification with echocardiography is an issue. No gold standard for MR quantification by noninvasive cardiac imaging has been defined so far. Only a moderate agreement has been shown between echocardiography, either with transthoracic or transesophageal approaches, and CMR in MR quantification, as supported by numerous comparative studies. A higher agreement is evidenced when echocardiographic 3D techniques are used. CMR is superior to echocardiography in the calculation of the RegV, RegF, and ventricular volumes and can provide myocardial tissue characterization. However, echocardiography remains fundamental in the pre-operative anatomical evaluation of the mitral valve and of the subvalvular apparatus. The aim of this review is to explore the accuracy of MR quantification provided by echocardiography and CMR in a head-to-head comparison between the two techniques, with insight into the technical aspects of each imaging modality.