Quantification of primary mitral regurgitation by echocardiography: A practical appraisal

Point-of-care ultrasound diagnosis of acute valvular emergencies

INTRODUCTION

Acute valvular emergencies, a time-sensitive diagnosis, are nearly impossible to diagnose without ultrasound, and missing the diagnosis can significantly impact patient outcomes. Many emergency physicians lack access to echo technicians and may be uncomfortable performing the ultrasound themselves. Approaching the paucity of review articles, none of which are focused for the emergency physician, can be quite daunting, even for those with extensive ultrasound training.

OBJECTIVE

Our goal is to provide a simple resource for emergency physicians to utilize ultrasound to diagnose acute valvular emergencies. We created a concise review that includes relevance and approach to the diagnosis, complete with live ultrasound images, reference cards, and focused figures for in-the-moment reference.

METHODS

A team of ultrasound fellowship-trained emergency medicine physicians determined the highest yield emergent conditions and oversaw the project. Each team member reviewed the etiology, incidence, and level of evidentiary support for each condition and then provided a guide to the appropriate procedure and evaluation with relevant additional guidance. An in-house graphics team was consulted to prepare original, concise figures for easy reference. All sections of the manuscript and figures were reviewed for accuracy and ease of use.

DISCUSSION

Critical aortic stenosis, infective endocarditis, left ventricular outflow tract obstruction, mitral stenosis, and mitral regurgitation were identified diagnoses for which ultrasound can provide immediate diagnostic information for emergency physicians.

CONCLUSION

The use of ultrasound in the emergency department setting is a critical adjunct to care for patients with acute valvular emergencies. One should always consider a comprehensive, cardiology-performed echocardiogram in these scenarios.

Impact of Sex on Severity Assessment and Cardiac Remodeling in Primary Mitral Regurgitation

Background

Women with severe primary mitral regurgitation (MR) have lower surgery rates than men and could suffer from delayed referral for mitral valve (MV) intervention, exposing them to an increased risk of postoperative adverse outcomes.

Objectives

The purpose of this study was to assess the sex-based differences in patients with primary MR.

Methods

The study sample consisted of 420 patients (median age: 62 years, 26% women) with primary MR due to valve prolapse referred for preoperative assessment who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging. Multiple endpoints (abnormally increased left ventricular size, NYHA functional class III/IV, severe left atrial [LA] dilatation, pulmonary hypertension) were studied using areas under the curves and logistic regression models.

Results

Women were older than men, had higher NYHA functional class and larger indexed LA volumes (all P ≤ 0.031), despite displaying lower MR effective regurgitant orifice area, regurgitant volumes (RegVol), and ventricular volumes than men (all P ≤ 0.002). The optimal cut-off values of RegVol associated with abnormally increased left ventricular size according to reference normal values were lower in women (TTE: 67 ml, CMR: 50 ml) than in men (TTE: 77 ml, CMR: 65 ml). MR regurgitant fraction, but not RegVol, was associated in women and men with NYHA functional class III/IV, severe LA dilatation, and pulmonary hypertension (all areas under the curves, P ≤ 0.024).

Conclusions

Despite having hallmarks of more advanced valvular heart disease, women with significant primary MR demonstrate lower mitral RegVol and ventricular volumes than men. In contrast, the systematic calculation of MR regurgitant fraction could standardize MR quantification irrespective of sex.

Exercise pulmonary hypertension by the mPAP/CO slope in primary mitral regurgitation

AIMS

Exercise-induced pulmonary hypertension (PH), defined by a mean pulmonary arterial pressure over cardiac output (mPAP/CO) slope >3 mmHg/L/min, has important diagnostic and prognostic implications. The aim of this study is to investigate the value of the mPAP/CO slope in patients with more than moderate primary mitral regurgitation (MR) with preserved ejection fraction and no or discordant symptoms.

METHODS AND RESULTS

A total of 128 consecutive patients were evaluated with exercise echocardiography and cardiopulmonary testing. Clinical outcome was defined as the composite of mitral valve intervention, new-onset atrial fibrillation, cardiovascular hospitalization, and all-cause mortality. The mean age was 63 years, 61% were male, and the mean LVEF was 66 ± 6%. The mPAP/CO slope correlated with peak VO2 (r = -0.52, P < 0.001), while the peak systolic pulmonary artery pressure (sPAP) did not (r = -0.06, P = 0.584). Forty-six per cent (n = 59) had peak exercise sPAP ≥60 mmHg, and 37% (n = 47) had mPAP/CO slope >3 mmHg/L/min. Event-free survival was 55% at 1 year and 46% at 2 years, with reduced survival in patients with mPAP/CO slope >3 mmHg/L/min (hazard ratio, 4.9; 95% confidence interval, 2.9-8.2; P < 0.001). In 53 cases (41%), mPAP/CO slope and peak sPAP were discordant: patients with slope >3 mmHg/L/mmHg and sPAP <60 mmHg (n = 21) had worse outcome vs. peak sPAP ≥60 mmHg and normal slope (n = 32, log-rank P = 0.003). The mPAP/CO slope improved predictive models for outcome, incremental to resting and exercise sPAP, and peak VO2.

CONCLUSION

Exercise PH defined by the mPAP/CO slope >3 mmHg/L/min is associated with decreased exercise capacity and a higher risk of adverse events in significant primary MR and no or discordant symptoms. The slope provides a greater prognostic value than single sPAP measures and peak VO2.

Chronic mild to moderate mitral regurgitation will not have an impact on left atrial strain parameters in the pediatric population

BACKGROUND

Left atrial strain (LAS) analysis represents a newer non-invasive, sensitive and specific technique for assessing left atrial (LA) function and early detection of its deformation and dysfunction. However, its applicability in mitral regurgitation (MR) in pediatric population remains unexplored, raising pertinent questions regarding its potential role in evaluating the severity and progression of the disease.

OBJECTIVE

To investigate the impact of chronic MR in children and adolescents on LA remodeling and function.

METHODS

The study included 100 participants. Patients with primary and secondary chronic MR lasting at least 5 years fit our inclusion criteria. The exclusion criteria from the study were: patients with functional mitral regurgitation due to primary cardiomyopathies, patients with artificial mitral valve, patients with MR who had previously undergone surgery due to obstructive lesions of the left heart (aortic stenosis, coarctation of the aorta), patients with significant atrial rhythm disorders (atrial fibrillation, atrial flutter). The echocardiographic recordings were conducted by two different cardiologists. Outcome data was reported as mean and standard deviation (SD) or median and interquartile range (Q1-Q3).

RESULTS

The study included 100 participants, of whom 50 had MR and the remaining 50 were without MR. The average age of all participants was 15.8 ± 1.2 years, with a gender distribution of 37 males and 63 females. There was a significant difference in the values of LA volume index (LAVI), which were higher in patients with MR (p= 0.0001), S/D ratio (and parameters S and D; p= 0.001, p= 0.0001, p= 0.013), mitral annulus radius (p= 0.0001), E/A ratio (p= 0.0001), as well as septal e' (m/s), lateral e' (m/s), and average E/e' ratio, along with the values of TV peak gradient and LV global longitudinal strain (%). There was no significant difference in LA strain parameters, nor in LA stiffness index (LASI).

CONCLUSION

Our findings revealed significant differences in several echocardiographic parameters in pediatric patients with MR relative to those without MR, providing insight into the multifaceted cardiac structural and functional effects of MR in this vulnerable population.