Influence of exercise-induced pulmonary hypertension on exercise capacity in asymptomatic degenerative mitral regurgitation

Mitral regurgitation assessment by cardiovascular magnetic resonance imaging during continuous in-scanner exercise: a feasibility study

PURPOSE

Exercise imaging using current modalities can be challenging. This was patient focused study to establish the feasibility and reproducibility of exercise-cardiovascular magnetic resonance imaging (EX-CMR) acquired during continuous in-scanner exercise in asymptomatic patients with primary mitral regurgitation (MR).

METHODS

This was a prospective, feasibility study. Biventricular volumes/function, aortic flow volume, MR volume (MR-Rvol) and regurgitant fraction (MR-RF) were assessed at rest and during low- (Low-EX) and moderate-intensity exercise (Mod-EX) in asymptomatic patients with primary MR.

RESULTS

Twenty-five patients completed EX-CMR without complications. Whilst there were no significant changes in the left ventricular (LV) volumes, there was a significant increase in the LVEF (rest 63 ± 5% vs. Mod-EX 68 ± 6%;p = 0.01). There was a significant reduction in the right ventricular (RV) end-systolic volume (rest 68 ml(60-75) vs. Mod-EX 46 ml(39-59);p < 0.001) and a significant increase in the RV ejection fraction (rest 55 ± 5% vs. Mod-EX 65 ± 8%;p < 0.001). Whilst overall, there were no significant group changes in the MR-Rvol and MR-RF, individual responses were variable, with MR-Rvol increasing by ≥ 15 ml in 4(16%) patients and decreasing by ≥ 15 ml in 9(36%) of patients. The intra- and inter-observer reproducibility of LV volumes and aortic flow measurements were excellent, including at Mod-EX.

CONCLUSION

EX-CMR is feasible and reproducible in patients with primary MR. During exercise, there is an increase in the LV and RV ejection fraction, reduction in the RV end-systolic volume and a variable response of MR-Rvol and MR-RF. Understanding the individual variability in MR-Rvol and MR-RF during physiological exercise may be clinically important.

Pulmonary Hypertension in Left Ventricular Valvular Diseases: A Comprehensive Review on Pathophysiology and Prognostic Value

Left ventricular (LV) valvular diseases, make up one of the most common etiologies for pulmonary hypertension (PH), and it is not well understood how and at which degree it affects prognosis. The aim of the present study was a comprehensive review of the pathophysiologic mechanism of PH in patients with LV valvular diseases and the prognostic value of baseline and post-intervention PH in patients undergoing interventional treatment. The pathophysiology of PH in patients with LV valvular diseases involves gradual elevation of left ventricular filling pressure and left atrial pressure, which are passively transmitted to the pulmonary circulation and raise pulmonary artery systolic pressure (PASP). A long-lasting exposure to elevated PASP progressively leads to initially functional and thereafter irreversible structural changes in the pulmonary vasculature, leading up to high pulmonary vascular resistance. Surgical treatment of severe LV valvular diseases is highly effective in patients without resting PH or those with exercise-induced PH (EIPH) before intervention. In the case of pre-operative PH, successful interventional therapy decreases PASP, but the post-operative cardiac and all-cause mortality remain higher compared to patients without pre-operative PH. Hence, it is of paramount importance to detect patients with severe LV valvulopathies before the development of PH, since they will get greater benefits from early intervention.

Exercise-Induced Pulmonary Hypertension: A Valid Entity or Another Factor of Confusion?

Exercise-induced pulmonary hypertension EIPH has been defined as an increase in mean pulmonary arterial pressure (mPAP) during exercise in otherwise normal values at rest. EIPH reflects heart and/or lung dysfunction and may precede the development of manifest pulmonary hypertension (PH) in a proportion of patients. It is also associated with decreased life expectancy in patients with heart failure with reduced ejection fraction (HFrEF) or left ventricle (LV) valvular diseases. Diastolic dysfunction exacerbated during exercise relates to increased LV filling pressure and left atrial pressure (LAP). In this context backward, transmitted pressure alone or accompanied with backward blood flow promotes EIPH. The gold standard of EIPH assessment remains the right heart catheterization during exercise, which is an accurate but invasive method. Alternatively, non-invasive diagnostic modalities include exercise stress echocardiography (ESE) and cardiopulmonary exercise testing (CPET). Both diagnostic tests are performed under gradually increasing physical stress using treadmill and ergo-cycling protocols. Escalating workload during the exercise is analogous to the physiological response to real exercise. The results of the latter techniques show good correlation with invasive measurements, but they suffer from lack of validation and cut-off value determination. Although it is not officially recommended, there are accumulated data supporting the importance of EIPH diagnosis in the assessment of other mild/subclinical or probably fatal diseases in patients with latent PH or heart failure or LV valvular disease, respectively. Nevertheless, larger, prospective studies are required to ensure its role in clinical practice.

Watchful surgery in asymptomatic mitral valve prolapse

The most common organic etiology of mitral regurgitation is degenerative and consists of mitral valve prolapse (MVP). Volume overload because of mitral regurgitation is the most common complication of MVP. Advocating surgery before the consequences of volume overload become irreparable restores life expectancy, but carries a risk of mortality in patients who are often asymptomatic. On the other hand, the post-surgical outcome of symptomatic patients is dismal and life expectancy is impaired. In the present article, we aim to bridge the gap between these two therapeutic approaches, unifying the concepts of watchful waiting and early surgery in a "watchful surgery approach".

Substitute parameters of exercise-induced pulmonary hypertension and usefulness of low workload exercise stress echocardiography in mitral regurgitation

In asymptomatic patients with mitral regurgitation (MR), data of exercise-induced pulmonary hypertension (EIPH) are limited, and feasibility of evaluating EIPH is not high. We aimed to investigate prognostic impact of EIPH and its substitute parameters. Exercise stress echocardiography (ESE) were performed in 123 consecutive patients with moderate to severe degenerative MR. The endpoint was a composite of death, hospitalization for heart failure, and worsening of symptoms. EIPH [tricuspid regurgitation peak gradient (TRPG) at peak workload ≥ 50 mmHg] was shown in 57 patients (46%). TRPG at low workload was independently associated with TRPG at peak workload (β = 0.67, p < 0.001). Early surgical intervention (within 6 months after ESE) was performed in 65 patients. Of the remaining 58 patients with the watchful waiting strategy, the event free survival was lower in patients with EIPH than in patients without EIPH (48.1 vs. 97.0% at 1-year, p < 0.001). TRPG at low workload ≥ 35.0 mmHg as well as EIPH were associated with poor prognosis in patients with the watchful waiting strategy. In conclusion, the importance of ESE and evaluating EIPH in patients with MR was re-acknowledged. TRPG at peak workload can be predicted by TRPG at low workload, and TRPG at low workload may be useful in real-world clinical settings.

Prognostic values of exercise echocardiography and cardiopulmonary exercise testing in patients with primary mitral regurgitation

AIMS

To compare the clinical significance of exercise echocardiography (ExE) and cardiopulmonary exercise testing (CPX) in patients with ≥moderate primary mitral regurgitation (MR) and discrepancy between symptoms and MR severity.

METHODS AND RESULTS

Patients consulting for ≥moderate discordant primary MR prospectively underwent low (25 W) ExE, peak ExE, and CPX within 2 months in Lille and Rennes University Hospital. Patients with Class I recommendation for surgical MR correction were excluded. Changes in MR severity, systolic pulmonary artery pressure (SPAP), left ventricular ejection fraction (LVEF), and tricuspid annular plane systolic excursion were evaluated during ExE. Patients were followed for major events (ME): cardiovascular death, acute heart failure, or mitral valve surgery. Among 128 patients included, 22 presented mild-to-moderate, 61 moderate-to-severe, and 45 severe MR. Unlike MR variation, SPAP and LVEF were successfully assessed during ExE in most patients. Forty-one patients (32%) displayed reduced aerobic capacity (peak VO2 < 80% of predicted value) with cardiac limitation in 28 (68%) and muscular or respiratory limitation in the 13 others (32%). ME occurred in 61 patients (47.7%) during a mean follow-up of 27 ± 21 months. Twenty-five Watts SPAP [hazard ratio (HR) (95% confidence interval, CI) = 1.03 (1.01-1.06), P = 0.003] and reduced aerobic capacity [HR (95% CI) = 1.74 (1.03-2.95), P = 0.04] were independently predictive of ME, even after adjustment for MR severity. The cut-off of 55 mmHg for 25 W SPAP showed the best accuracy to predict ME (area under the curve = 0.60, P = 0.05).

CONCLUSION

In patients with ≥moderate primary MR and discordant symptoms, 25 W exercise pulmonary hypertension, defined as an SPAP ≥55 mmHg, and poor aerobic capacity during CPX are independently associated with adverse events.

The prognostic value of exercise-induced pulmonary hypertension in asymptomatic patients with primary mitral regurgitation

BACKGROUND

We examined whether the early development of exercise-induced pulmonary hypertension (EIPH) and right ventricular dysfunction during exercise stress echocardiography (ESE) may predict clinical deterioration in so-called "asymptomatic" patients with primary, at least moderate mitral regurgitation (MR).

METHODS

79 consecutive patients underwent a symptom-limited, graded ESE protocol on semi-supine bicycle at the beginning of the study. During the test, we assessed symptom development, test duration, and the following echocardiographic parameters: MR severity, maximum velocity of the tricuspid regurgitation jet (TR Vmax), pulmonary artery systolic pressure (PASP), and tricuspid annulus systolic excursion (TAPSE). All patients were then followed-up for at least 12 months for clinical end-points (heart failure-related symptoms requiring pharmaceutical therapy, heart failure hospitalization, and/or mitral valve surgery in case of refractory symptoms).

RESULTS

After 16 ± 4 months of follow-up, 75 patients completed the study; 26 of them achieved any clinical end-point and were classified as 'high-risk', while the rest (49 patients) were assigned to the 'low-risk' group. High-risk group showed significantly higher exercise-induced TR Vmax and PASP levels at maximum workload of ESE than low-risk counterparts (p<0.001). Based on receiver operating characteristic analysis, the early (within the first two stages of ESE or up to 50 W) steep rise of calculated PASP ≥51 mmHg (TR Vmax ≥3.4 m/s) had a 92.3% sensitivity and 100% specificity to predict clinical deterioration within the following year. That cut-off value seemed superior predictor than peak value of PASP at the end of ESE. TAPSE levels during ESE did not add prognostic value in our sample.

CONCLUSION

This is the first study demonstrating that the early development of EIPH has prognostic value in asymptomatic patients with primary at least moderate MR and may become a new valid determinant of mitral valve surgery. Additional larger prospective studies are needed to validate our findings.

Manual zur Indikation und Durchführung spezieller echokardiographischer Anwendungen

Das zweite Manual zur Indikation und Durchführung der Echokardiographie bezieht sich auf spezifische Anwendungen der Echokardiographie und besondere Fragestellungen bei speziellen Patientengruppen. Dabei stehen v. a. praktische Aspekte im Vordergrund. Methodisch etabliert sind die transösophageale Echokardiographie, die Stressechokardiographie und die Kontrastechokardiographie. Bei nahezu allen echokardiographischen Untersuchungen spielen aktuell 3‑D-Echokardiographie und Deformationsbildgebung eine Rolle. Das gesamte Spektrum der echokardiographischen Möglichkeiten wird derzeit in Notfall- und Intensivmedizin, bei der Überwachung und Führung von Katheterinterventionen, bei strukturellen Herzerkrankungen, bei herzchirurgischen Operationen, bei der Nachsorge von kardialen Unterstützungssystemen, bei kongenitalen Vitien im Erwachsenenalter und bei der Versorgung von hochinfektiösen Patienten in Pandemiezeiten angewandt. Die diagnostischen Fortschritte der konventionellen und modernen echokardiographischen Anwendungen stehen im Fokus dieses Manuals. Die 3‑D-Echokardiographie zur Charakterisierung der kardialen Morphologie und die Deformationsbildgebung zur Objektivierung der kardialen Funktion sind bei vielen Indikationen im klinischen Alltag etabliert. Die Stressechokardiographie zur Ischämie‑, Vitalitäts- und Vitiendiagnostik, die Bestimmung der koronaren Flussreserve und die Kontrastechokardiographie bei der linksventrikulären Wandbewegungsanalyse und kardialen Tumordetektion finden zunehmend klinische Anwendung. Wie für die konventionelle Echokardiographie im ersten Manual der Echokardiographie 2009 beschrieben, erfordert der Einsatz moderner echokardiographischer Verfahren die standardisierte Dokumentation und Akquisition bestimmter Bildsequenzen bei optimierter Geräteeinstellung, da korrekte und reproduzierbare Auswertungen nur bei guter Bildqualität möglich sind.

Prognostic impact of invasive exercise haemodynamics in patients with severe mitral regurgitation

OBJECTIVES

Abnormal invasive exercise haemodynamics in asymptomatic patients with severe mitral regurgitation were associated with higher regurgitation burden. We analysed the association between parameters of invasive exercise testing with mortality and valve surgery compared to guideline defined non-invasive criteria.

METHODS

This single centre, retrospective cohort study assesses the association of invasive exercise haemodynamics and mortality with and without surgery in patients with severe mitral regurgitation and normal ejection fraction (≥55%) as primary outcome. The secondary outcome was the need for mitral valve surgery in 113 asymptomatic patients primarily managed conservatively.

RESULTS

We identified 314 patients [age 59 years (standard deviation 13), 27% female] with available exercise haemodynamics with a median follow-up of 8.2 (interquartile range 5.2-11.2) years. Five-year survival rate was 93.0%. Pulmonary capillary wedge pressure at maximum exercise >30 mmHg was the only parameter independently associated with mortality after adjustment for age and guideline criteria [hazard ratio (HR) 2.7 (1.3-5.6), P = 0.007]. In the 113 patients primarily managed conservatively, maximum pulmonary capillary wedge pressure was independently associated with mitral valve surgery during follow-up in multivariable analysis (HR 2.10 (1.32-3.34), P = 0.002; after adjustment for workload and weight: HR 1.31 (1.14-1.52), P < 0.001], whereas systolic pulmonary artery pressure and current guideline criteria were not. Adding maximum pulmonary capillary wedge pressure >25 mmHg improved the predictive power of current guideline criteria for surgery (area under the curve 0.61-0.68, P = 0.02).

CONCLUSIONS

Invasive exercise haemodynamics predict mortality and improve prognostic information about surgery during follow-up derived from current guideline criteria in asymptomatic patients with severe mitral regurgitation.

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.

Physiological and prognostic differences between types of exercise stress echocardiography for functional mitral regurgitation

Objective

Secondary mitral regurgitation (MR) demonstrates dynamic change during exercise. This prospective observational study aimed to compare exercise stress echocardiography (ESE) where handgrip exercise (handgrip-ESE) or semisupine ergometer exercise was performed (ergometer-ESE) for patients with secondary MR.

Methods

Handgrip-ESE and symptom-limited ergometer-ESE were performed for 53 patients (median age (IQR): 68 (58–78) years; 70% male) on the same day. Baseline global longitudinal strain (GLS) was 9.2% (6.0%–14.0%) and MR volume was 20 (14–26) mL. All-cause death and cardiac hospitalisation were tracked for median 439 (101–507) days.

Results

Handgrip-ESE induced slightly but significantly greater degrees of MR increase (median one grade increase; p<0.001) than ergometer-ESE, although the changes in other parameters, including GLS (+1.1% vs −0.6%, p<0.001), were significantly smaller. Correlations between the two examinations with respect to the changes in the echocardiographic parameters were weak. Kaplan-Meier analyses revealed poor improvement in GLS during ergometer-ESE, but not the change in MR, was associated with adverse events (p=0.0065). No echocardiographic change observed during handgrip-ESE was prognostic. After adjusting for a clinical risk score, GLS changes during ergometer-ESE remained significant in predicting the adverse events (HR 0.39, p=0.03) A subgroup analysis in patients with moderate or greater MR at baseline (n=27) showed the same results as in the entire cohort.

Conclusions

The physiological and prognostic implications of handgrip-ESE and ergometer-ESE findings significantly differ in patients with left ventricular dysfunction and secondary MR. The type of exercise to be performed in ESE should be carefully selected.

Prognostic Value of Peak Exercise Systolic Pulmonary Arterial Pressure in Asymptomatic Primary Mitral Valve Regurgitation

BACKGROUND

The contribution of exercise echocardiography in primary asymptomatic mitral regurgitation (MR) remains debated. The aim of this study was to gain evidence regarding its usefulness in this setting and to investigate the prognostic value of peak exercise systolic pulmonary artery pressure (SPAP).

METHODS

One hundred seventy-seven patients (mean age, 56 ± 13 years; 69% men) with moderate to severe (grade 3+) or severe (grade 4+) degenerative MR and preserved left ventricular ejection fraction, in sinus rhythm, referred for clinically indicated exercise echocardiography were identified. The end point, MR-related events, was a composite of all-cause death or occurrence of symptoms, heart failure, atrial fibrillation, left ventricular ejection fraction < 60%, left ventricular end-systolic diameter ≥ 45 mm, or resting SPAP > 50 mm Hg.

RESULTS

At rest, effective regurgitant orifice area was 48 ± 16 mm², regurgitant volume 74 ± 26 mL, and SPAP 32 ± 7 mm Hg, and MR was severe in 138 patients (78%). Peak exercise SPAP was 55 ± 10 mm Hg. Positive results on exercise testing motivated surgery in 26 patients, 11 underwent prophylactic surgery, 10 were lost to follow-up, and 130 were included in the outcome analysis. During a follow-up period of 19 ± 7 months, 31 MR-related events (24%) were reported. Peak exercise SPAP was predictive of outcomes in univariate analysis (P = .01) and after adjustment for age, gender, MR severity, and resting SPAP (P < .05). Peak exercise SPAP ≥ 50 mm Hg was associated with worse event-free survival (hazard ratio, 5.24; 95% CI, 1.77-15.53; P = .003), but not the threshold of ≥60 mm Hg proposed in previous guidelines (hazard ratio, 1.70; 95% CI, 0.71-4.03; P = .24).

CONCLUSIONS

The present findings support the use of exercise echocardiography for risk stratification in patients with asymptomatic primary MR and suggest a lower peak exercise SPAP threshold (50 mm Hg) than previously recommended to define the timing of intervention. Prospective studies are needed to confirm these findings.

Exercise capacity in asymptomatic patients with significant primary mitral regurgitation: independent effect of global longitudinal left ventricular strain

Background

Despite preserved left ventricular ejection fraction (LVEF), patients with significant primary mitral regurgitation (MR) often have reduced exercise capacity. In asymptomatic patients with ≥3+ primary MR undergoing rest-stress echocardiography (RSE), we sought to evaluate the incremental impact of left ventricular global longitudinal strain (LV-GLS) on exercise capacity.

Methods

A total of 660 asymptomatic patients with ≥3+ primary MR, non-dilated LV and LVEF ≥60% (mean age, 57±14 years, 66% men, body mass index or BMI 25±4 kg/m²) who underwent RSE at our center between 2001 and 2013 were included. Standard RSE data were obtained. Average resting LV-GLS was measured using Velocity Vector Imaging.

Results

Mean mitral effective regurgitant orifice, resting right ventricular systolic pressure (RVSP) and LV-GLS were 0.45±0.2 cm², 31±12 mmHg and -21.7%±2%, respectively; 28% had flail mitral leaflet. Mean metabolic equivalents (METs) and post-stress RVSP were 9.9±3, and 46±15 mmHg; 28% achieved <100% age-gender predicted METs. No patient had ischemia or significant arrhythmias. On logistic regression, resting LV-GLS [odds ratio (OR), 1.40, 95% confidence interval (CI): 1.21-1.55, BMI (OR, 1.11, 95% CI: 1.06-1.17)] and resting RVSP 1.22 (1.02-1.49) were independent predictors of exercise capacity. Area under the curve for association between 100% age-gender predicted METs and various factors were as follows: (I) BMI (0.60, 95% CI: 0.55-0.65, P<0.001); (II) resting RVSP (0.57, 95% CI: 0.52-0.62, P=0.006) and LV-GLS (0.66, 95% CI: 0.61-0.70, P<0.001).

Conclusions

In asymptomatic patients with ≥3+ primary MR, non-dilated LV and preserved LVEF, LV-GLS is independently associated with exercise capacity, beyond known predictors.

Exercise Testing in Mitral Regurgitation

Mitral regurgitation (MR) is the second most common valvular heart disease referred for corrective surgery. Diagnostic and management dilemmas are not uncommon when dealing with MR patients. Exercise testing plays an important role in sorting out some of these clinical challenges. In primary asymptomatic MR, exercise testing allows symptom assessment, confident link of symptoms to valve disease severity, safe deferral of surgery for the next 1-year in patients with preserved exercise capacity, insights into the mechanism of exercise-induced dyspnea and helps in individual risk stratification. Moreover, exercise testing in the form of exercise stress echocardiography is also useful in the evaluation of patients with secondary ischemic MR for risk stratification as well as for the detection of patients with moderate ischemic MR in whom mitral valve repair at the time of surgical revascularization may add benefit.

Accuracy of Echocardiography to Estimate Pulmonary Artery Pressures With Exercise: A Simultaneous Invasive-Noninvasive Comparison

BACKGROUND

Exercise echocardiography is often applied as a noninvasive strategy to screen for abnormal pulmonary hemodynamic response, but it is technically challenging, and limited data exist regarding its accuracy to estimate pulmonary arterial pressure during exercise.

METHODS AND RESULTS

Among 65 patients with exertional intolerance undergoing upright invasive exercise testing, tricuspid regurgitation (TR) Doppler estimates and invasive measurement of pulmonary arterial pressure at rest and peak exercise were simultaneously obtained. TR Doppler envelopes were assessed for quality. Correlation, Bland-Altman, and receiver-operating characteristic curve analyses were performed to evaluate agreement and diagnostic accuracy. Mean age was 62±13 years, and 31% were male. High-quality (grade A) TR Doppler was present in 68% at rest and 34% at peak exercise. For grade A TR signals, echocardiographic measures of systolic pulmonary arterial pressure correlated reasonably well with invasive measurement at rest (r=0.72, P<0.001; bias, -2.9±8.0 mm Hg) and peak exercise (r=0.75, P<0.001; bias, -1.9±15.6 mm Hg). Lower quality TR signals (grade B and C) correlated poorly with invasive measurements overall. In patients with grade A TR signals, mean pulmonary arterial pressure-to-workload ratio at a threshold of 1.4 mm Hg/10 W was able to identify abnormal pulmonary hemodynamic response during exercise (>3.0 mm Hg/L per minute increase), with 91% sensitivity and 82% specificity (area under the curve, 0.90; 95% confidence interval, 0.77-1.0; P=0.001).

CONCLUSIONS

Agreement between echocardiographic and invasive measures of pulmonary pressures during upright exercise is good among the subset of patients with high-quality TR Doppler signal. While the limits of agreement are broad, our results suggest that in those patients, sensitivity is adequate to screen for abnormal pulmonary hemodynamic response during exercise.

Exercise echocardiography for structural heart disease

Since the introduction of transcatheter structural heart intervention, the term "structural heart disease" has been widely used in the field of cardiology. Structural heart disease refers to congenital heart disease, valvular heart disease, and cardiomyopathy. In structural heart disease, valvular heart disease is frequently identified in the elderly. Of note, the number of patients who suffer from aortic stenosis (AS) and mitral regurgitation (MR) is increasing in developed countries because of the aging of the populations. Transcatheter aortic valve replacement and percutaneous mitral valve repair has been widely used for AS and MR, individually. Echocardiography is the gold standard modality for initial diagnosis and subsequent evaluation of AS and MR, although the difficulties in assessing patients with these diseases still remain. Here, we review the clinical usefulness and prognostic impact of exercise echocardiography on structural heart disease, particularly on AS and MR.