The Role of Left Atrial Fibrosis in Mitral Valve Repair Surgery (ALIVE Trial)

Overview

Rationale: Patients with mitral valve insufficiency suffer from left atrial remodeling. Atrial fibrosis is part of this remodeling process. The presence of atrial fibrosis is associated with adverse events. Currently, mitral valve repair surgery is the ultimate treatment for severe primary mitral valve insufficiency. The main indications and timing for surgery are severe mitral valve insufficiency with symptoms or left ventricular dysfunction. However, the role of atrial fibrosis in this process remains undetermined despite its well-recognized clinical implications. Characterization of atrial fibrosis patterns in mitral valve insufficiency patients might be potentially valuable for the indication and timing of mitral valve repair surgery in order to improve clinical outcomes. To date, however, mitral valve insufficiency patients suffering from left atrial remodeling have hardly been studied using these new imaging techniques. Therefore, the investigators intend to combine advanced cardiac MRI and post-processing techniques prior to and after mitral valve repair surgery to gain more insight in the clinical implications of atrial fibrosis in this patient population. It is hypothesized that the atrial fibrosis surface area paradoxically will increase after mitral valve surgery because of global shrinkage of the left atrium caused by the reversed remodeling process. As a consequence, more frequently atrial fibrosis related events including (paroxysmal) atrial fibrillation, may be observed in these patients. Objective: To assess the effects of (reduced) volume overload on the left atrial wall texture (presence, amount and location of atrial fibrosis) and associated geometry and function in patients with mitral valve insufficiency, prior to and after mitral valve repair surgery. Study design: Single center pilot study. Study population: The research population consists of mitral valve insufficiency patients scheduled for elective surgical mitral valve repair (N=20) according to the current European guideline criteria.

Patients with mitral valve insufficiency frequently suffer from left atrial remodeling, caused by volume overload and subsequent atrial dilatation. The associated myocardial stretch and increased wall tension, trigger a cascade of pathways leading to the occurrence of atrial fibrosis as part of the remodeling process. The clinical relevance of this atrial fibrosis, is that its presence is associated with an increased risk of atrial fibrillation, heart failure, pulmonary hypertension, a reduced quality of life and eventually a shorter life expectancy. In addition, in patients suffering from atrial fibrillation, the presence and amount of left atrial fibrosis was found to be a strong predictor for ablation efficacy and long-term outcome. In daily clinical practice, mitral valve insufficiency is managed either by medical or surgical therapy. However, since medical therapy is often not sufficient for patients with severe primary mitral valve insufficiency, surgical intervention remains the ultimate treatment option for these patients. In general, valve repair is the preferred type of surgery, since it has better clinical results compared to valve replacement. Currently, the indication and timing for valve surgery is mainly based on the severity of mitral valve insufficiency and the presence of symptoms and/or severity of left ventricular dysfunction. For clinical decision making and patient stratification for mitral valve surgery, the presence of atrial fibrosis is currently not taken in account, despite its well-recognized clinical implications. Detection of atrial fibrosis patterns in patients with severe mitral valve insufficiency, however, may be potentially valuable for the indication and timing of mitral valve repair surgery to improve clinical outcomes. Improved insight into atrial fibrosis patterns and changes after mitral valve repair due to reverse remodeling, may help clinicians in their clinical decision making and timing for surgery. Today, quantification of atrial fibrosis can be routinely performed using cardiac Magnetic Resonance Imaging (MRI) techniques and advanced post-processing tools, offering non-invasive tissue characterization in thin-walled structures. To date, mitral valve insufficiency patients suffering from left atrial remodeling have hardly been studied using these new imaging techniques. Therefore, in this study, the investigators want to combine advanced cardiac MRI and post-processing techniques prior to and after mitral valve repair surgery to gain insight on the clinical role and predictive value of atrial fibrosis in this patient population. In addition, the investigators aim to assess the effects of (reduced) volume overload on atrial wall texture, geometry and function. It is hypothesized that the atrial fibrosis surface area paradoxically will increase after mitral valve surgery because of global shrinkage of the left atrium caused by the reversed remodeling process. As a consequence, more frequently atrial fibrosis related events including (paroxysmal) atrial fibrillation, may be observed in these patients. With this insight, cardiac MRI can become clinical valuable for the indication and timing of surgical intervention in these patients. Surgical therapy might be renounced for example when a substantial increase of fibrosis surface is expected post-surgically causing a higher risk for atrial fibrillation, heart failure, pulmonary hypertension and a reduced quality of life. On the contrary, surgical therapy might be considered in an earlier stage of disease when the amount of fibrosis is still limited regarding its expected post-surgical development.