The main finding of the present study is to show significant quantitative reduction of mitral regurgitation in patients treated due to ADHF. In 40% of patients, the reduction led to a change in mitral regurgitation severity class, which may be the most important factor in the decision-making process concerning surgical treatment of such patients.
The results of our current study demonstrate the dynamic nature of mitral regurgitation in patients with ADHF. Until now, studies describing mitral regurgitation severity during the treatment of acute cardiovascular decompensation, as assessed by echocardiography, were mainly based on semi-quantitative measurements. In our work, apart from semi-quantitative measurements, results from quantitative assessment of the mitral regurgitation are also presented. The reduction in mitral regurgitation severity during ADHF treatment is associated with a combination of many different factors such as a reduction in afterload, pressure gradient change between the left ventricle and left atrium, and a reduction in left ventricular and mitral annular dimensions, which are associated with a reduction in EROA [7]. In line with previous observations involving groups of patients treated for acute heart failure [7], our study also showed a significant reduction in the dimensions of the left atrium, mitral annular diameter, and EROA, assessed using the PISA method, when comparing baseline measurements with discharge measurements. On the other hand, no significant reduction was recorded in the LVEDV when assessed by the biplanar method. This could be related to the baseline characteristics of the study population, which was affected by advanced left ventricular remodeling at baseline.
The presence of significant ischemic mitral regurgitation in patients with a history of myocardial infarction and heart failure with reduced ejection fraction significantly worsens the long-term prognosis, regardless of the LVEF, age, and NYHA functional class [11–12]. In contrast to primary mitral regurgitation, there is still no clear evidence whether a reduction in secondary mitral regurgitation is associated with improved survival [13]. Nevertheless, minimally invasive procedures such as the percutaneous edge-to-edge repair system (MitraClip) are commonly used, which can provide a reduction in the severity of heart failure symptoms and are associated with a reduction in unfavorable remodeling of the left ventricular myocardium [14]. As shown in the COAPT trial, the appropriate selection of heart failure patients for the MitraClip procedure leads to a reduction in the number of hospitalizations and decreased mortality in the 24-month follow-up [15].
Our study illustrates the importance of a solid understanding of mitral regurgitation dynamics in heart failure patients in everyday clinical practice. Importantly, our study showed a significant reduction in mitral regurgitation severity (8 patients with severe regurgitation at baseline vs. 2 patients at discharge) as a result of standard treatment for cardiovascular decompensation. This may have a significant impact on the selection of management strategies in patients, including the decision to perform surgical treatment for valvular disease. It is also worth mentioning that in the group of patients with initially severe mitral regurgitation admitted to the hospital due to symptoms of ADHF, mitral regurgitation reduction to moderate or mild classes do not necessarily imply an improved prognosis. This was demonstrated in the group of patients with ADHF and dynamic mitral regurgitation initially meeting the criteria of a severe wave, which then significantly reduces during treatment process, where the prognosis is much worse than in the patients with insignificant regurgitation, but at a similar level as in the group of patients with persistent severe mitral regurgitation [3]. Therefore, patients with dynamic and severe mitral regurgitation also require greater attention and further follow-up to introduce a suitable treatment, including surgical management if needed.
A limitation of our study is the fact that it is a single-center analysis with a relatively small study group, involving patients diagnosed with ischemic (48%) and non-ischemic (52%) heart dysfunction. However, we believe that due to the high statistical significance of the observed changes, this does not interfere with our quantitative, qualitative, and clinical analyses of mitral regurgitation associated with ADHF.