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Significance of Mitral Regurgitation in Acute Heart Failure
Quick Takes
- Moderate or severe mitral regurgitation (MR) is common in patients hospitalized with acute heart failure.
- Women were more likely than men to have at least moderate MR, regardless of LVEF.
- Moderate or severe MR was independently associated with 1-year mortality in patients with LVEF <50%, but not in those with LVEF >50%.
Study Questions:
In patients with acute decompensated heart failure (ADHF), what is the prevalence and prognostic significance of mitral regurgitation (MR), and what are possible sex and racial differences?
Methods:
The Heart Failure Community Surveillance component of the ARIC (Atherosclerosis Risk in Communities) study performed continuous surveillance of HF hospitalizations for a biracial (white and black) patient population aged >55 years in four different US communities (in NC, MS, MN, and MD) from 2005-2014. Exclusion criteria included those without echocardiographic/left ventricular ejection fraction (LVEF)/MR data, or prior history of valve surgery. Demographics and patient characteristics were stratified by LVEF (<50% or ≥50%) and MR severity (none/mild MR vs. moderate/severe MR). The primary outcome was all-cause mortality at 1 year.
Results:
Between 2005 and 2014, there were 17,931 ADHF hospitalizations in patients ≥55 years old, of whom 49.2% had an LVEF <50% (44.7% female, 34.1% black) and 50.8% had an LVEF ≥50% (65.7% female, 26.8% black). In those with LVEF <50%, moderate or severe MR was present in 44.5% versus 27.5% in those with LVEF ≥50%. Women were more likely than men to have moderate or severe MR regardless of LVEF (LVEF <50%: odds ratio [OR], 1.21; 95% confidence interval [CI] 1.1-1.3; LVEF >50%: OR, 1.52; 95% CI, 1.36-1.69). In both the LVEF <50% and ≥50% groups, those with moderate or severe MR were older and more likely to have a history of atrial fibrillation (p < 0.0001 for all). In those hospitalized with LVEF ≥50%, whites were less likely than blacks to have moderate or severe MR (OR, 0.72; 95% CI, 0.64-0.82). MR severity was independently associated with higher 1-year mortality in those with LVEF <50% (OR, 1.3; 95% CI, 1.16-1.45), while higher mortality was not observed in the LVEF ≥50% cohort (OR, 0.99; 95% CI, 0.88-1.11).
Conclusions:
1) In patients with ADHF, there is a high prevalence of MR, notably 44% in those with LVEF <50%, and 27% in those with LVEF ≥50%. 2) Women are more likely than men to have a higher degree of MR severity, irrespective of their LVEF. 3) In ADHF patients with LVEF ≥50%, moderate or severe MR is more likely in white patients than black patients. 4) In patients with LVEF <50%, moderate or severe MR is independently associated with 1-year all-cause mortality.
Perspective:
ADHF is one of the leading causes of hospitalizations in this country for patients >65 years old, while MR is one of the most commonly diagnosed valvular impairments. This study set out to understand possible factors that could be contributing to poor outcomes in ADHF patients. The study looked at a biracial population with relatively equal distribution of both sexes across four different centers in the United States, making these results more generalizable to the US population. This is also one of the first large investigations to stratify results by LVEF, thereby including a previously understudied population of those with low-normal and normal EF. However, a limitation in this study is the lack of differentiation between the underlying etiology of the MR (primary vs. secondary/functional), though the authors suggest that a substantial portion of MR must have been functional. Given this assumption, it is not surprising that the degree of MR is merely a marker of HF severity and corresponds to a greater 1-year mortality in the LVEF <50% group. The study also looked at MR at one time-point only, thereby not accounting for its dynamic nature that can vary over time with volume status. The gender and race findings were interesting, and future work is needed to better characterize the HF population at risk for MR, with the aim of improving timely diagnosis and management of these high-risk patients.
Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Valvular Heart Disease, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Echocardiography/Ultrasound, Mitral Regurgitation
Keywords: Atrial Fibrillation, Diagnostic Imaging, Echocardiography, Heart Failure, Heart Valve Diseases, Mitral Valve Insufficiency, Risk Factors, Stroke Volume, Ventricular Function, Left
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