Effects of exercise on left ventricular performance determined by echocardiography in chronic, severe mitral regurgitation secondary to mitral valve prolapse

2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the valvular heart disease guideline provides recommendations for clinicians to diagnose and manage valvular heart disease as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to March 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected database relevant to this guideline. Structure: Many recommendations from the earlier valvular heart disease guidelines have been updated with new evidence and provides newer options for diagnosis and treatment of valvular heart disease. This summary includes only the recommendations from the full guideline which focus on diagnostic work-up, the timing and choice of surgical and catheter interventions, and recommendations for medical therapy. The reader is referred to the full guideline for graphical flow charts, text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in developing these guidelines.

Mitral Prolapse: An Old Mysterious Entity - The Incremental Role of Multimodality Imaging in Sports Eligibility

Mitral valve prolapse is generally a benign condition characterized by fibromyxomatous changes of the mitral leaflet with displacement into the left atrium and late-systolic regurgitation. Although it is an old clinical entity, it still arouses perplexity in diagnosis and clinical management. Complications, such as mitral regurgitation (MR), atrial fibrillation, congestive heart failure, endocarditis, ventricular arrhythmias, and sudden cardiac death (SCD), have been reported. A large proportion of the overall causes of SCD in young competitive athletes is explained by mitral valve prolapse. Recent studies have shown the fibrosis of the papillary muscles and inferobasal left ventricular wall in mitral valve prolapse, suggesting a possible origin of ventricular fatal arrhythmias. Athletes with mitral valve prolapse and MR should undergo annual evaluations including physical examination, echocardiogram, and exercise stress testing to evaluate the cardiovascular risks of competitive sports and obtain the eligibility. In this setting, multimodality imaging techniques – echocardiography, cardiac magnetic resonance, and cardiac computed tomography – should provide a broad spectrum of information, from diagnosis to clinical management of the major clinical profiles of the disease.

Customized exercise echocardiography: beyond detection of coronary artery disease

Exercise echocardiography has been established as a reliable diagnostic tool for assessment of myocardial ischemia. However, more recent advances in its technique have expanded its routine clinical use to include quantification of exercise-induced diastolic dysfunction, exercise-induced pulmonary hypertension, and dynamic assessment of mitral and aortic valve function. The indications for exercise echocardiography have increased to include cardiac symptoms such as exertional dyspnea, fatigue, and limited exercise capacity. In light of its expanded capability for evaluating cardiovascular function, we believe that exercise echocardiography should be utilized in a new paradigm of personalized cardiology, in which we regularly investigate individual patient symptoms for endpoints beyond critical myocardial ischemia, for example, exercise-induced pulmonary hypertension. We refer to this refocused use of exercise echocardiography as "customized exercise echocardiography." In this review article, we present current scientific evidence to support our proposed role and discuss the logistical requirements for proper test performance of customized exercise echocardiography.

The role of cardiopulmonary exercise test in mitral and aortic regurgitation: it can predict post-operative results

BACKGROUND

We evaluated the efficacy of the cardiopulmonary exercise test as an objective indicator of functional status and as a pre-operative prognostic indicator in patients with mitral regurgitation (MR) and aortic regurgitation (AR).

METHODS

Cardiopulmonary exercise tests and echocardiography were performed in 47 patients (MR: 30, AR: 15, MR + AR: 2) before surgery and repeated one year after surgery. We compared the New York Heart Association (NYHA) functional class, peak oxygen consumption rate (VO2peak), exercise duration, left ventricular dimension and ejection fraction, before and after surgery.

RESULTS

Initial VO2peak and exercise duration were significantly different according to NYHA class. A year later, NYHA functional class improved from 2.1 +/- 0.1 to 1.4 +/- 0.1 (p < 0.001). The VO2peak was significantly increased (21.7 +/- 1.0 to 23.7 +/- 1.0 mL/kg per min, p = 0.008) and exercise duration also increased (521.7 +/- 35.9 to 623.3 +/- 35.7 seconds, p < 0.001). When patients were analysed according to their post-operative NYHA functional class, those with class I showed significantly different pre-operative VO2peak (class I: 23.7 +/- 1.1, II: 18.3 +/- 1.5 mL/kg per min, p = 0.005) and exercise durations (class I: 587.5 +/- 43.2, II: 415.6 +/- 55.7 seconds, p = 0.02). Patients with higher pre-operative VO2peak (19.0 mL/kg per min) more frequently became NYHA functional class I than those with a lower pre-operative VO2peak (76.7% vs. 35.3%, p = 0.02). But baseline left ventricular dimension and ejection fraction by echocardiography were not different between post-operative class I and II group.

CONCLUSION

VO2peak and exercise duration are excellent parameters to evaluate the subjective functional class and to predict the post-operative functional class of patients with MR and/or AR. Patients with a pre-operative VO2peak of 19.0 mL/kg per min or more will have a better functional status one year after surgery.

Progress in mitral and aortic regurgitation

Over the past 15 years there has been rapid and dramatic change in the therapy for valvular heart disease. When mitral and aortic regurgitation are severe, they inevitably cause left ventricular damage, eventually resulting in death. However, when surgical correction of these lesions is timed appropriately, longevity can approach that of a normal population after surgery. As surgical techniques have improved, surgery is now indicated earlier in the course of these diseases. It is clear that some patients with mitral and aortic regurgitation require surgery even though they are entirely asymptomatic. However, it must be emphasized that mitral and aortic regurgitation are quite different from one another. These different lesions result in different loading conditions, different pathophysiologies, and have different means for surgical correction. All of these issues impact on the proper timing of surgery and are discussed.

Assessment of left ventricular systolic function in patients with idiopathic mitral valve prolapse using dobutamine stress echocardiography

BACKGROUND

Some previous studies performed with radionuclide ventriculography and thallium scintigraphy reported that patients with idiopathic mitral valve prolapse (MVP) had some degree of left ventricular (LV) systolic dysfunction and that this dysfunction was more commonly found in symptomatic patients.

HYPOTHESIS

The aim of the present prospective study was to investigate LV systolic function and its relationship with symptoms in patients with MVP with dobutamine stress test without associated certain mitral regurgitation and coronary artery disease.

METHODS

Thirty-three patients with echocardiographically diagnosed idiopathic MVP were enrolled into the study and were divided into two groups as symptomatic (MVP-s) and asymptomatic (MVP-a). Patients underwent dobutamine stress echocardiography (DSE) to determine wall motion abnormalities and ejection fraction (EF) changes during rest state and increased heart rates. Results were compared with the DSE findings of 25 healthy individuals.

RESULTS

Symptomatic patients (MVP-s) had lower EFs during the pretest period than the control group (59.0 +/- 4.8% and 68.3 +/- 5.7%, respectively, p < 0.05). Basal wall motion abnormalities were found in one patient in the MVP-a group (6%) and in two patients in the MVP-s group (12%). During DSE, new wall motion abnormalities (inferoapical dyskinesia) occurred in two patients in the MVP-s group at submaximal heart rates. For EF values calculated when patients reached submaximal heart rate, the MVP-s group showed only a 2.7 +/- 3.1% increase from baseline values. This increase was 5.1 +/- 3.8% in the MVP-a group and 9.3 +/- 4.3% in the control group (p < 0.05 between MVP-s and control groups).

CONCLUSION

There is a close relationship between symptoms and ventricular function in patients with idiopathic MVP, and although many asymptomatic patients had nearly normal LV function, a subgroup of symptomatic patients showed diminished LV function and wall motion abnormalities.

Exercise echocardiographic assessment in severe mitral regurgitation

In chronic severe mitral regurgitation, minimum morbidity and mortality is achieved by applying surgical correction before left ventricular dysfunction becomes irreversible. This requires detection of subtle signs of early ventricular decompensation, for which isotonic stress echocardiography is more accurate than is use of resting indices of contractile function alone. We perform serial 6-monthly stress echocardiography for patients with severe mitral regurgitation, and recommend surgery when the exercise end-systolic volume index or ejection fraction reaches the cutoff values in Table 4 or if there is a clear adverse trend. Exercise echocardiography is more accurate than is exercise electrocardiography for detecting concomitant coronary disease prior to revascularization. Stress testing is also an objective measure of symptoms. Color-Doppler stress echocardiography can detect those patients whose mitral regurgitation worsens (or even develops de novo) with exercise, which can explain unexpected symptoms. Stress echocardiography, therefore, provides a comprehensive and cost-effective evaluation of patients with mitral regurgitation that combines functional, diagnostic, and prognostic information.

Stress echocardiography in valvular heart disease

Stress echocardiography has been widely accepted as an important diagnostic and prognostic tool in the assessment of known or suspected coronary artery disease. Its use in valvular heart disease, to date, has been more limited, but is continuing to grow as the technology and the understanding of valvular disorders progress. In this article, we will review the current literature regarding the use of both exercise and pharmacological stress testing in conjunction with echocardiography in the settings of native and prosthetic mitral and aortic valve disease. We will also discuss the limitations of this modality and touch upon possible future areas of investigation.

Management of mitral regurgitation. Optimal timing for surgery

Chronic mitral regurgitation is a progressive disorder that can produce myocardial dysfunction in the absence of symptoms. Improvements in surgical techniques have resulted in earlier intervention, at times in asymptomatic patients. This article discusses the factors that influence prognosis, reviews the evidence supporting earlier intervention and provides guidelines for the management of patients with this lesion.

Determinants of functional capacity in chronic mitral regurgitation unassociated with coronary artery disease or left ventricular dysfunction

Impaired functional capacity is common in patients with mitral regurgitation (MR), but the determinants of functional capacity in patients with normal left ventricular (LV) function are unclear. Forty patients with chronic, isolated, nonrheumatic MR with no coronary artery disease underwent exercise echocardiography with continuous expired gas analysis. Cardiac output and regurgitant stroke volume were measured at rest and immediately after exercise by pulsed-wave Doppler echocardiography. For controls, 17 healthy volunteers without MR were also studied. Patients achieved a significantly lower VO2max compared with controls (25.6 +/- 7.7 vs 31.7 +/- 7.7 ml/kg/min, p = 0.008). VO2max showed better correlations with exercise cardiac output than with cardiac output at rest in both patients and controls. Multiple linear regression identified exercise cardiac output (partial r = 0.65), patient age (partial r = -0.56), and gender as independent determinants of VO2max (multiple R = 0.85, p <0.001). Cardiac output at rest, LV ejection fraction, regurgitant stroke volume, and fraction were not significant determinants. With exercise, the regurgitant stroke volume increased in 13 patients and decreased in 27 patients. The former 13 patients had a significantly lower exercise cardiac output (7.4 +/- 2.5 vs 9.4 +/- 2.6 L/min, p = 0.026). Patients who stopped exercise due to dyspnea (n = 7) had a significantly lower exercise cardiac output and VO2max compared with those who stopped due to fatigue (n = 33), with no differences in resting or exercise regurgitant volume. Patients with an increase in LV end-systolic volume with exercise (n = 8) also had a significantly lower exercise cardiac output (6.9 +/- 1.9 vs 9.2 +/- 2.7 L/min, p = 0.037) and showed a trend toward a lower VO2max (21 +/- 7.5 vs 26 +/- 6.4 ml/kg/min, p = 0.07). In patients with chronic MR, exercise cardiac output is the major determinant of VO2max. Regurgitant volume and fraction are not related to functional capacity. Limitations in functional capacity in these patients may be more related to a diminished cardiac reserve than to a large regurgitant volume.