Prognostic value of exercise stress echocardiography in patients with secondary mitral regurgitation: a long-term follow-up study

Prevalence, mechanisms, and prognostic impact of dynamic mitral regurgitation assessed by isometric handgrip exercise

AIMS

The extent of mitral regurgitation (MR) may vary depending on the haemodynamic situation; thus, exercise testing plays an important role in assessing the haemodynamic relevance of MR. We aim to assess prevalence, mechanisms, and prognostic impact of exercise-induced changes in MR in patients with degenerative MR (DegMR) and functional MR (FMR).

METHODS AND RESULTS

We enrolled 367 patients with at least mild MR who underwent standardized echocardiography at rest and during handgrip exercise. Handgrip exercise led to an increase in MR by one grade or more in 19% of DegMR and 28% of FMR patients. In FMR, patients with exercise-induced increases in MR, handgrip exercise led to a reduction in left ventricular stroke volume index, being maintained in DegMR patients. Exercise-induced changes in systolic pulmonary artery pressure were linked to changes in effective regurgitant orifice area (DegMR: r = 0.456; P < 0.001; FMR: r = 0.326; P < 0.001). Thus, 26% of patients with DegMR and FMR developed pulmonary hypertension during exercise. In both cohorts, a significant proportion of patients with non-severe MR at rest and exercise-induced severe MR underwent mitral valve surgery/intervention during follow-up. In FMR patients (but not in DegMR patients), early mitral valve surgery/intervention was independently associated with lower event rates during follow-up [0.177 (0.027-0.643); P = 0.025].

CONCLUSIONS

Handgrip exercise echocardiography provides important information regarding the dynamic nature of MR, exercise-induced changes in left ventricular function, and pulmonary circulation with subsequent consequences for further therapeutic decision making. Thus, it should be considered as a diagnostic tool in symptomatic patients with non-severe MR at rest.

Changes in exercise stress echocardiographic parameters before and after transcatheter mitral valve edge-to-edge repair

The safety and feasibility are still not well known for exercise-induced mitral regurgitation (MR). This study is aimed to assess and compare the hemodynamic and symptomatic changes in patients with significant secondary MR during exercise stress echocardiography (ESE) before and after transcatheter edge-to-edge repair (TEER). The study included a total of 15 patients with secondary MR who underwent ESE before and after TEER using the MitraClip system (Abbott, Abbott Park, IL, USA). Echocardiographic data of ESE were collected both before the procedure and during the follow-up visit at 3 months. During the one-year postoperative observation period, the rate of readmission due to heart failure was 13% (n = 2), with no recorded fatalities. Although no significant differences of ESE data were observed in exercise-induced pulmonary hypertension or cardiac output before and after the repair, the severity of MR was significantly improved after the procedure, both at rest (2 [2-3] vs. 1 [1-2], p = 0.0125) and during ESE (3 [3-3] vs. 1 [1-1], p < 0.0001). Furthermore, the New York Heart Association Functional Classification was improved (3 [3-3] vs. 1 [1-1], p < 0.0001) after treatment. For a supplemental analysis, MR during ESE was significantly improved not only in cases with atrial secondary MR but also in ventricular secondary MR. Transcatheter edge-to-edge repair for exercise-induced MR resulted in a significant improvement in postoperative MR severity and subjective symptoms. These results are novel, as they have not been extensively reported previously, particularly among Japanese patients.

Stress echocardiography in valvular heart disease

Valvular heart disease (VHD) has been a significant health problem, particularly in developed countries, in relation to the aging population. Recent developments in the management of VHD require a more accurate assessment of disease severity to determine the need for transcatheter interventions or open heart surgery. Stress echocardiography is a crucial imaging modality for identifying the underlying pathology of VHD. Optimal administration of exercise or intravenous drugs may reveal hemodynamic abnormalities under stress without posing an invasive risk. Therefore, the implementation of stress echocardiography is recommended for determining interventional indications and risk stratification in mitral regurgitation and aortic stenosis. In addition, recent evidence has accumulated regarding the usefulness of stress echocardiography in various conditions including mitral stenosis, aortic regurgitation, and post-interventional VHD. Here, we summarize the current evidence and future perspectives on stress echocardiography in VHD.

Practical Echocardiographic Approach of the Regurgitant Mitral Valve Assessment

Mitral regurgitation is the second-most frequent valvular heart disease in Europe after degenerative aortic stenosis. It is associated with significant morbidity and mortality, and its prevalence is expected to increase with population aging. Echocardiography is the first diagnostic approach to assess its severity, constituting a challenging process in which a multimodality evaluation, integrating quantitative, semiquantitative and qualitative methods, as well as a detailed evaluation of the morphology and function of both left ventricle and atria is the key. In this review, we would like to provide a practical diagnosis approach on the mitral valve regurgitation mechanism, severity quantification, and planning of future therapeutic options.

Dynamic Secondary Mitral Regurgitation: Current Evidence and Challenges for the Future

Heart failure (HF) is a challenging situation in healthcare worldwide. Secondary mitral regurgitation (SMR) is a common condition in HF patients with reduced ejection fraction (HFrEF) and tends to be increasingly associated with unfavorable clinical outcomes as the severity of SMR increases. It is worth noting that SMR can deteriorate dynamically under stress. Over the past three decades, the characteristics of dynamic SMR have been studied. Dynamic SMR contributes to the reduction in exercise capacity and adverse clinical outcomes. Current guidelines refer to the indication of transcatheter edge-to-edge repair (TEER) for significant SMR based on data from the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial if symptomatic despite optimal guideline-directed medical therapy (GDMT) and cardiac resynchronization therapy (CRT), but nonpharmacological treatment for dynamic SMR remains challenging. In HFrEF patients with LV dyssynchrony and dynamic SMR, CRT can improve LV dyssynchrony and subsequently attenuate SMR at rest and during exercise. Also, a recent study suggests that TEER with GDMT and CRT is more effective in symptomatic patients with HFrEF and dynamic SMR than GDMT and CRT alone. Further studies are needed to evaluate the safety and efficacy of nonpharmacological treatments for dynamic SMR. In this review, current evidence and challenges for the future of dynamic SMR are discussed.

Cardiac Imaging for the Assessment of Left Atrial Mechanics Across Heart Failure Stages

The left atrium (LA) is emerging as a key element in the pathophysiology of several cardiac diseases due to having an active role in contrasting heart failure (HF) progression. Its morphological and functional remodeling occurs progressively according to pressure or volume overload generated by the underlying disease, and its ability of adaptation contributes to avoid pulmonary circulation congestion and to postpone HF symptoms. Moreover, early signs of LA dysfunction can anticipate and predict the clinical course of HF diseases before the symptom onset which, particularly, also applies to patients with increased risk of HF with still normal cardiac structure (stage A HF). The study of LA mechanics (chamber morphology and function) is moving from a research interest to a clinical application thanks to a great clinical, prognostic, and pathophysiological significance. This process is promoted by the technological progress of cardiac imaging which increases the availability of easy-to-use tools for clinicians and HF specialists. Two-dimensional (2D) speckle tracking echocardiography and feature tracking cardiac magnetic resonance are becoming essential for daily practice. In this context, a deep understanding of LA mechanics, its prognostic significance, and the available approaches are essential to improve clinical practice. The present review will focus on LA mechanics, discussing atrial physiology and pathophysiology of main cardiac diseases across the HF stages with specific attention to the prognostic significance. Imaging techniques for LA mechanics assessment will be discussed with an overlook on the dynamic (under stress) evaluation of the chamber.

Prognostic impact of transcatheter mitral valve repair in patients with exercise-induced secondary mitral regurgitation

AIMS

Although exercise-induced secondary mitral regurgitation (MR) is known to have a poor prognosis, the therapeutic strategy towards this condition remains to be investigated. In the present study, we aimed to investigate the prognostic impact of transcatheter mitral valve repair (TMVr) using the MitraClip in patients with exercise-induced secondary MR.

METHODS AND RESULTS

Of the 200 consecutive patients with secondary MR who underwent exercise stress echocardiography, 46 (23%) that presented with exercise-induced secondary MR [i.e. increase in effective regurgitant orifice area (EROA) of ≥ 0.13 cm2] were enrolled in the present investigation. The composite endpoints of all-cause mortality and hospitalization for heart failure were evaluated. Of the 46 patients included in the current cohort, 19 (41%) underwent TMVr and 27 (59%) were medically managed (control group). Although the TMVr group tended to present with a greater EROA at rest (0.26 ± 0.10 vs. 0.20 ± 0.08 cm2, P = 0.047), there were no differences in the EROA changes during exercise between the two groups (0.18 ± 0.10 vs. 0.18 ± 0.04 cm2, P = 0.940). While the TMVr group reported a higher event-free survival rate after the 13-month follow-up period (log-rank P = 0.017), the Cox proportional-hazard analysis suggested the TMVr to be associated with clinical outcomes (hazard ratio: 0.419, P = 0.044).

CONCLUSION

As opposed to the medical management, TMVr treatment was associated with a lower risk of composite endpoints in patients with exercise-induced secondary MR. Exercise stress echocardiography is considered to have played an important role in decision-making for secondary MR.

Updated knowledge and practical implementations of stress echocardiography in ischemic and non-ischemic cardiac diseases: an expert consensus of the Working Group of Echocardiography of the Hellenic Society of Cardiology

Stress echocardiography (SE) is a well-established and valid technique, widely-used for the diagnostic evaluation of patients with ischemic and non-ischemic cardiac diseases. This statement of the Echocardiography Working Group of the Hellenic Society of Cardiology summarizes the consensus of the writing group regarding the applications of SE, based on the expertise of their members and on a critical review of current medical literature. The main objectives of the consensus document include a comprehensive review of SE methodology and training, focusing on the preparation, the protocols used and the analysis of the SE images and an updated, evidence-based knowledge about SE applications on ischemic and non-ischemic heart diseases, such as in cardiomyopathies, heart failure and valvular heart disease.

Clinical application of stress echocardiography for valvular heart disease

Stress echocardiography is widely used to assess several cardiovascular diseases, including ischemic heart disease, valvular heart disease (VHD), heart failure, congenital heart disease, and pulmonary hypertension. In valvular heart disease with asymptomatic severe or symptomatic non-severe status, stress echocardiography plays a central role in the management. As of 2017, the updated American College of Cardiology/American Heart Association and European Society of Cardiology/European Association for Cardio-Thoracic Surgery VHD guidelines recommended stress testing to (1) confirm symptoms and (2) evaluate the hemodynamic response to exercise. In patients with undetermined VHD severity in the presence of low-flow status, it can also be helpful to determine whether the VHD is severe based on flow-dependent changes in response to stress. The clinical indications of stress echocardiography in VHD have expanded with growing evidence for prognosis and being an early marker for interventions. As a result, demand has increased in major cardiology societies for the standardization of stress echocardiography in VHD. Echocardiographic centers should be aware of the clinical potential of stress echocardiography to ensure its optimal application and performance in VHD. This article reviews the clinical application of stress echocardiography, including dobutamine, semisupine bicycle, treadmill, and leg-positive pressure for VHD patient management, and focuses on the current consensus regarding the use of stress echocardiography in VHD. Stress echocardiography is safe and should be encouraged, especially in heart valve clinics, to understand the complex mechanism in asymptomatic patients.