The Syndrome of Severe Mitral Regurgitation with Normal Left Atrial Pressure

Reappraisal of the Concept and Implications of Pulmonary Hypertension in Degenerative Mitral Regurgitation

BACKGROUND

European and U.S. clinical guidelines diverge regarding pulmonary hypertension (PHTN) in degenerative mitral regurgitation (DMR). Gaps in knowledge underpinning these divergences affect risk assessment and management recommendations attached to systolic pulmonary pressure (SPAP) in DMR.

OBJECTIVES

This study sought to define PHTN links to DMR severity, prognostic thresholds, and independent outcome impact in a large quantitative DMR registry.

METHODS

This study gathered a large multicentric registry of consecutive patients with isolated moderate-to-severe DMR, with DMR and SPAP quantified prospectively at diagnosis.

RESULTS

In 3,712 patients (67 ± 15 years, 36% women) with ≥ moderate-to-severe DMR, effective regurgitant orifice (ERO) was 0.42 ± 0.19 cm2, regurgitant volume 66 ± 327 mL/beat and SPAP 41 ± 16 mm Hg. Spline-curve analysis showed excess mortality under medical management emerging around SPAP 35 mm Hg and doubling around SPAP 50 mm Hg. Accordingly, severe pulmonary hypertension (sPHTN) (SPAP ≥50 mm Hg) was detected in 916 patients, moderate pulmonary hypertension (mPHTN) (SPAP 35-49 mm Hg) in 1,128, and no-PHTN (SPAP <35 mm Hg) in 1,668. Whereas SPAP was strongly associated with DMR-ERO, nevertheless excess mortality with sPHTN (adjusted HR: 1.65; 95% CI: 1.24-2.20) and mPHTN (adjusted HR: 1.44; 95% CI: 1.11-1.85; both P ≤ 0.005) was observed independently of ERO and all baseline characteristics and in all patient subsets. Nested models demonstrated incremental prognostic value of mPHTN and sPHTN (all P < 0.0001). Despite higher operative risk with mPHTN and sPHTN, DMR surgical correction was followed by higher survival in all PHTN ranges with strong survival benefit of early surgery (<3 months). Postoperatively, excess mortality was abolished (P ≥ 0.30) in mPHTN, but only abated in sPHTN.

CONCLUSIONS

This large international registry, with prospectively quantified DMR and SPAP, demonstrates a Doppler-defined PHTN impact on mortality, independent of DMR severity. Crucially, it defines objectively the new and frequent mPHTN range, independently linked to excess mortality under medical management, which is abolished by DMR correction. Thus, at DMR diagnosis, Doppler-SPAP measurement defining these new PHTN ranges, is crucial to guiding DMR management.

Left atrial and left ventricular strain dynamics with echocardiography in asymptomatic children with mitral regurgitation

Left atrial (LA) dilatation is a strong predictor of cardiovascular morbidity and mortality. Strain parameters evaluating LA functions have gained importance in assessing cardiovascular health. This study aimed to investigate the relationship between LA and left ventricular (LV) strain, using speckle-tracking echocardiography, and assess the impact of vena contracta on LV functioning in asymptomatic children with mitral regurgitation. We evaluated 45 asymptomatic mitral regurgitation patients, categorized as mild, moderate, and severe. LV strain was significantly lower in the moderate group (-17.8 ± 3.7%) and further reduced in the severe group (16 ± 2.1%) compared to the reference group (20.5 ± 6.2%). Conversely, LA reservoir strain was higher in the severe and moderate groups (38 ± 12.9% and 40.7 ± 9.5%, respectively) compared to the controls (31.3 ± 7.5%; p < 0.0001). The severe group also displayed a milder depression of contraction (12.2%) compared to the moderate group (13 ± 7.2%). In the moderate and severe groups, LV strain correlated significantly with vena contracta (r=-0.858; p = 0.04), with vena contracta emerging as the only independent predictor for LV longitudinal strain. ROC curve analysis indicated a cut-off value > 5.65 mm for vena contracta, which had a positive predictive value of 75% for predicting LV function impairment. In conclusion, this study emphasizes the significance of assessing LA and ventricular strain in asymptomatic children with mitral regurgitation. Furthermore, vena contracta with diameters greater than 5.6 mm may alert clinicians to the possibility of LV function impairment. These findings offer valuable insights for the follow-up and management of paediatric patients with mitral regurgitation, enabling early detection of potential complications and improved patient outcomes.

Timing of Surgery for Asymptomatic Primary Mitral Regurgitation: Possible Value of Early, Serial Measurements of Left Ventricular Sphericity

Asymptomatic primary mitral regurgitation due to myxomatous degeneration of the mitral valve leaflets may remain so for long periods, even as left ventricular function progresses to a decompensated stage. During the early compensated stage, the ventricle's initial response to the volume overload is an asymmetric increase in the diastolic short axis dimension, accomplished by a diastolic shift of the interventricular septum into the right ventricular cavity, creating a more spherical left ventricular diastolic shape, increasing diastolic filling and stroke volume. Early valve repair is recommended to reduce postoperative left ventricular dysfunction. Early serial measurements of left ventricular sphericity index [LV-Si]. during the compensated stage of mitral regurgitation might identify subtle changes in left ventricular shape and assist in determining the optimal earliest timing for surgical intervention.

Left atrial appendage volume is an independent predictor of atrial arrhythmia recurrence following cryoballoon pulmonary vein isolation in persistent atrial fibrillation

Purpose

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation in persistent AF (persAF), and cryoballoon PVI emerged as an initial ablation strategy. Symptomatic atrial arrhythmia recurrence following successful PVI in persAF is observed more frequently than in paroxysmal AF. Predictors for arrhythmia recurrence following cryoballoon PVI for persAF are not well described, and the role of left atrial appendage (LAA) anatomy is uncertain.

Methods

Patients with symptomatic persAF and pre-procedural cardiac computed tomography angiography (CCTA) images undergoing initial second-generation cryoballoon (CBG2) were enrolled. Left atrial (LA), pulmonary vein (PV) and LAA anatomical data were assessed. Clinical outcome and predictors for atrial arrhythmia recurrence were evaluated by univariate and multivariate regression analysis.

Results

From May 2012 to September 2016, 488 consecutive persAF patients underwent CBG2-PVI. CCTA with sufficient quality for measurements was available in 196 (60.4%) patients. Mean age was 65.7 ± 9.5 years. Freedom from arrhythmia was 58.2% after a median follow-up of 19 (13; 29) months. No major complications occurred. Independent predictors for arrhythmia recurrence were LAA volume (HR 1.082; 95% CI, 1.032 to 1.134; p = 0.001) and mitral regurgitation ≥ grade 2 (HR, 2.49; 95% CI 1.207 to 5.126; p = 0.013). LA volumes ≥110.35 ml [sensitivity: 0.81, specificity: 0.40, area under the curve (AUC) = 0.62] and LAA volumes ≥9.75 ml (sensitivity: 0.56, specificity 0.70, AUC = 0.64) were associated with recurrence. LAA-morphology, classified as chicken-wing (21.9%), windsock (52.6%), cactus (10.2%) and cauliflower (15.3%), did not predict outcome (log-rank, p = 0.832).

Conclusion

LAA volume and mitral regurgitation were independent predictors for arrhythmia recurrence following cryoballoon ablation in persAF. LA volume was less predictive and correlated with LAA volume. LAA morphology did not predict the clinical outcome. To improve outcomes in persAF ablation, further studies should focus on treatment strategies for persAF patients with large LAA and mitral regurgitation.

Left atrial disease and left atrial reverse remodelling across different stages of heart failure development and progression: a new target for prevention and treatment

The left atrium is a dynamic chamber with peculiar characteristics. Stressors and disease mechanisms may deeply modify its structure and function, leading to left atrial remodelling and disease. Left atrial disease is a predictor of poor outcomes. It may be a consequence of left ventricular systolic and diastolic dysfunction and neurohormonal and inflammatory activation and/or actively contribute to the progression and clinical course of heart failure through multiple mechanisms such as left ventricular filling and development of atrial fibrillation and subsequent embolic events. There is growing evidence that therapy may improve left atrial function and reverse left atrial remodelling. Whether this translates into changes in patient's prognosis is still unknown. In this review we report current data about changes in left atrial size and function across different stages of development and progression of heart failure. At each stage, drug therapies, lifestyle interventions and procedures have been associated with improvement in left atrial structure and function, namely a reduction in left atrial volume and/or an improvement in left atrial strain function, a process that can be defined as left atrial reverse remodelling and, in some cases, this has been associated with improvement in clinical outcomes. Further evidence is still needed mainly with respect of the possible role of left atrial reverse remodelling as an independent mechanism affecting the patient's clinical course and as regards better standardization of clinically meaningful changes in left atrial measurements. Summarizing current evidence, this review may be the basis for further studies.

Prevalence of rheumatic heart disease in adults from the Brazilian Amazon Basin

BACKGROUND

Rheumatic heart disease (RHD) continues to be a burden in low- and middle-income countries and prevalence estimates are lacking from South America. We aimed to determine the prevalence of RHD in the Brazilian Amazon Basin.

METHODS

We examined a random sample of adults (≥18 years) from the general population, who underwent echocardiographic image acquisition by a medical doctor. All images were analyzed according to (i) the 2012 World Heart Federation criteria and (ii) a simplified algorithm for RHD from a previously validated risk score (categories: low-, medium-, high-risk) which involved assessment of the mitral valve (leaflet thickening and excessive motion, regurgitation jet length) and aortic valve (thickening and any regurgitation).

RESULTS

A total of 488 adults were screened (mean age 40 ± 15 years, 38% men). The prevalence of RHD was 39/1000 adults (n = 17 definite and n = 2 borderline). Fourteen (74%) had pathological mitral regurgitation, four (21%) mitral stenosis, 0 (0%) pathological aortic regurgitation and six (32%) both mitral and aortic valve disease. None had a prior diagnosis of RHD, 10 (53%) had positive cardiac auscultation and two (11%) reported a history of rheumatic fever. The simplified algorithm identified four (21%) adults as low-risk, six (32%) as intermediate, and nine (47%) as high-risk.

CONCLUSIONS

The prevalence of RHD was 39/1000 in adults from the Brazilian Amazon Basin, indicating the need for screening programs in remote areas. A simplified model was only able to categorize every second case of RHD as high-risk. External validation of simplified screening models to increase feasibility in clinical practice are encouraged.

Invasive hemodynamics are equivocal for functional outcomes after MitraClip

Objectives

To evaluate invasive hemodynamics in assessing MC therapy success as well as evaluate its effectiveness as a predictor of functional outcomes.

Background

Mitral regurgitation grade is a poor predictor of functional outcomes after a MitraClip. There is a paucity of data on invasive hemodynamics as a predictor of outcomes.

Methods

Sixty-nine patients underwent MC between 2015 and 2018 at the University of Minnesota Medical Center and were retrospectively analyzed. Invasive hemodynamics were performed before and after device deployment with transesophageal echocardiographic guidance. Statistical analysis was performed using STATA version 16. Student's t test was used for continuous variables and Pearson's chi-squared test for categorical variables. Mann-Whitney test was performed for continuous variables where data were not normally distributed. Logistic and linear regression were used to investigate relationships between variables and outcomes.

Results

A total of 69 patients were included in the study. The mean age was 83 (75-87) years and 38 (55%) were male. Eighty-one percentage had >/= NYHA III symptoms. Eighty-seven percentage had severe MR. Pulmonary capillary wedge pressure was 20 (15-24). Overall, there was significant improvement in left atrial pressure including mean left atrial pressure index, MR, and NYHA class after MC (<.001). There was no significant association between invasive hemodynamics (including left atrial mean pressure index or its reduction rate) and functional outcomes (p = NS). MR grade was also not predictive of functional outcomes.

Conclusion

Left atrial pressure may not be a significant predictor of functional outcomes, and, in isolation, may not be an improvement over MR grade.

Mitral prolapsing volume is associated with increased cardiac dimensions in patients with mitral annular disjunction

Introduction

In patients with mitral annular disjunction (MAD), it can be difficult to assess the severity of mitral regurgitation (MR), as they present with a prolapsing volume (i.e. volume resulting from mitral valve prolapse, blood volume shift) rather than a regurgitant jet. The influence of the mitral prolapsing volume (MPV) on cardiac dimensions is unknown. We hypothesised that the severity of MR is underestimated in these patients. Our aim was to measure MPV and to investigate its influence on cardiac dimensions in patients with MAD.

Methods

We retrospectively included 131 consecutive patients with MAD from our institution’s echocardiographic database. Transthoracic echocardiography was used to assess MPV. Additionally, we established a control group of 617 consecutive patients with degenerative mitral valve disease and performed propensity score matching.

Results

Median MPV in the MAD group was 12 ml. MPV was an independent predictor for left ventricular end-diastolic (LVEDD) and end-systolic diameter (LVESD) and left atrial volume (all p < 0.001). In patients with large prolapsing volumes (> 15 ml), LVEDD (56 ± 6 mm vs 51 ± 6 mm, p < 0.001), LVESD [38 mm (34–41) vs 34 mm (31–39), p < 0.01] and left atrial volume [105 ml (86–159) vs 101 ml (66–123), p = 0.04] were significantly increased compared to matched patients with degenerative mitral valve disease and similarly assessed severity of MR.

Conclusion

Due to a volume shift based on the MPV rather than an actual regurgitant jet, MR severity cannot be assessed adequately in MAD patients. Increased MPV induces ventricular and atrial enlargement. These findings warrant future studies to focus on MPV as an additional parameter for assessment of the severity of MR in MAD patients.

Supplementary Information

The online version of this article (10.1007/s12471-021-01575-6) contains supplementary material, which is available to authorized users.

HAND1 loss-of-function within the embryonic myocardium reveals survivable congenital cardiac defects and adult heart failure

AIMS

To examine the role of the basic Helix-loop-Helix (bHLH) transcription factor HAND1 in embryonic and adult myocardium.

METHODS AND RESULTS

Hand1 is expressed within the cardiomyocytes of the left ventricle (LV) and myocardial cuff between embryonic days (E) 9.5-13.5. Hand gene dosage plays an important role in ventricular morphology and the contribution of Hand1 to congenital heart defects requires further interrogation. Conditional ablation of Hand1 was carried out using either Nkx2.5 knockin Cre (Nkx2.5Cre) or α-myosin heavy chain Cre (αMhc-Cre) driver. Interrogation of transcriptome data via ingenuity pathway analysis reveals several gene regulatory pathways disrupted including translation and cardiac hypertrophy-related pathways. Embryo and adult hearts were subjected to histological, functional, and molecular analyses. Myocardial deletion of Hand1 results in morphological defects that include cardiac conduction system defects, survivable interventricular septal defects, and abnormal LV papillary muscles (PMs). Resulting Hand1 conditional mutants are born at Mendelian frequencies; but the morphological alterations acquired during cardiac development result in, the mice developing diastolic heart failure.

CONCLUSION

Collectively, these data reveal that HAND1 contributes to the morphogenic patterning and maturation of cardiomyocytes during embryogenesis and although survivable, indicates a role for Hand1 within the developing conduction system and PM development.

Hemodynamics rounds: Hemodynamics of mitral valve interventions

Mitral valvulopathy presents as regurgitation, stenosis, or mixed disease and can occur in both native and prosthetic valves. Such disease develops in conjunction with pathophysiologic changes in the left atrium (LA) and drives changes in LA compliance, pressure, and thus clinical syndromes. With advances in the understanding and treatment of structural heart disease and in the setting of higher-risk patient populations, less-invasive transcatheter approaches have become increasingly commonplace in the treatment of mitral valve disease. Over time, transcatheter mitral valve interventions have evolved to include paravalvular leak closure, mitral valve repair, and mitral valve replacement. Parallel to this evolution, advances in invasive intracardiac pressure monitoring, particularly at the level of the LA, have also occurred. These advances emphasize the unique interplay between mitral valve disease and LA function; account for limitations of noninvasive assessment; and guide beneficial outcomes in each area of transcatheter mitral valve intervention. As a result, continuous transseptal LA pressure monitoring has developed into an indispensable instrument in successful percutaneous mitral valve intervention, complementing traditional noninvasive assessment.

Characteristics and outcomes of patients with normal left atrial pressure undergoing transcatheter mitral valve repair

Objective

A subset of patients at the time of transcatheter mitral valve repair (TMVR) will have normal left atrial pressure (LAP) (<13 mm Hg) despite having severe mitral regurgitation (MR). The goal of this study was to determine clinical characteristics and outcomes in patients with normal LAP undergoing TMVR.

Methods

A single-centre retrospective cohort of consecutive patients who underwent transcatheter edge-to-edge mitral valve clip and continuous LAP monitoring between 5/1/2014 and 5/1/2018 was analysed. One-year mortality was compared by Kaplan–Meier survival curves. Multivariable analysis was performed to identify predictors of normal LAP and 1 year mortality.

Results

Of the 204 patients undergoing TMVR, 65% were men and the mean age was 81. Of these patients, 31 (15%) had normal LAP (mean LAP 10.5 mm Hg, mean V wave 16.5 mm Hg) and 173 had elevated LAP (mean LAP 19 mm Hg, mean V wave 32.5 mm Hg). The prevalence of severe MR was not different between groups, although the normal LAP group had significantly lower effective regurgitant orifice area and regurgitant volume. Other notable baseline characteristics including prior cardiac surgery, atrial fibrillation, hypertension, diabetes, congestive heart failure, body mass index, mechanism of MR and ejection fraction were similar between groups. However, there was an increased prevalence of chronic lung disease (CLD) (45.2% vs 17.3%, p<0.001) in the normal LAP group. On multivariate analysis, the only significant predictor of normal LAP was the presence of CLD (OR 4.79 (1.83–12.36), p=0.001) and 1-year mortality was significantly higher in the normal LAP group (32.3% vs 12.7%, p=0.006). After adjustment for comorbidities, normal LAP was no longer a predictor of 1-year mortality (RR 1.62 (0.64–4.06), p=0.32); however, CLD (RR 3.44 (1.37–8.67), p=0.01) remained a statistically significant predictor.

Conclusion

Normal LAP at the time of TMVR is associated with a higher incidence of CLD which independently predicts increased 1-year mortality. In patients with CLD and apparently severe MR, measurement of LAP may help identify those with lower likelihood of benefit from TMVR.

Mitral regurgitation, left atrial structural and functional remodelling and the effect on pulmonary haemodynamics

AIMS

To assess the association between mitral regurgitation (MR) and left atrial (LA) structural and functional remodelling and their effect on pulmonary haemodynamics.

METHODS AND RESULTS

Consecutive unselected patients undergoing comprehensive echocardiography were enrolled. Parameters of cardiac structure and function were obtained as well as mitral effective regurgitant orifice area (ERO) and estimation of pulmonary artery systolic pressure (PASP). Measures of LA structure [LA volume (LAV)] and function [peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS) and conduit strain (CS)] were also calculated. The study population included 102 patients (mean age 70 ± 14 years, 42% women), with a mean ejection fraction of 52 ± 13%. MR was classified as organic due to mitral valve prolapse in 14 patients (14%) and functional in 88 patients (86%). Mean ERO was 0.12 ± 0.12 cm² and 86 patients (84%) had an ERO ≤0.2 cm² . ERO was significantly associated with worse measures of LA structure and function. Despite the low burden of MR, the association remained significant after adjusting for clinical and echocardiographic confounders (β: 3.7, P = 0.022 for LAV; β: -3.0, P = 0.003 for PALS; β: -1.8, P = 0.027 for PACS) and was significantly related with functional MR (P for interaction <0.001). ERO was also significantly associated with PASP, and measures of LA function (PALS and PACS) significantly modified this relationship (P for interaction <0.001).

CONCLUSIONS

Even a mild degree of MR contributes to LA remodelling and this relationship plays an active role in pulmonary circulation, suggesting a potential mechanism by which these parameters contribute to the development of heart failure.

Preoperative left atrial volume index is associated with postoperative outcomes in mitral valve repair for chronic mitral regurgitation

OBJECTIVE

To assess determinants of left atrial reverse remodeling after mitral valve repair and to evaluate the impact of preoperative left atrial volume on postoperative outcomes.

METHODS

We reviewed the records of 720 patients who underwent mitral valve repair from September 2008 to July 2015 and had preoperative measurement of left atrial volume index. We analyzed the association of preoperative left atrial volume index on early and late outcomes, and determined which baseline characteristics are associated with left atrial reverse remodeling, as measured by changes in left atrial volume index in 512 patients who had at least 1 postoperative measurement.

RESULTS

The median (interquartile range) preoperative left atrial volume index was 54.0 (44.0-66.0) mL/m². Preoperative left atrial volume index, age, body mass index, and atrial fibrillation were independently associated with the degree of left atrial reverse remodeling over the follow-up period. Reverse remodeling was greatest in patients with higher baseline left atrial volume index (P < .001), but less reverse remodeling was observed in patients with advanced age (P < .001), preoperative atrial fibrillation (P < .001), and extreme values of body mass index (P = .004), although these effects were moderately attenuated when limiting the analysis to 6-month follow-up. Secondary analysis demonstrated marginally significant effects of preoperative left atrial volume index on risks of early postoperative atrial fibrillation (P = .030) and late mortality (P = .077) after adjusting for age and sex.

CONCLUSIONS

In patients with degenerative mitral valve regurgitation who had mitral valve repair, preoperative left atrial volume index was associated with extent of left atrial reverse remodeling, risk of early postoperative atrial fibrillation, and late mortality. The majority of reverse remodeling occurs within the first month after operation and is greatest in younger patients.

Urgent mechanical circulatory support and transcatheter mitral valve repair for refractory hemodynamic compromise

Patients presenting with hemodynamic instability attributable to left ventricular systolic dysfunction and concomitant severe mitral regurgitation (MR) are increasingly recognized and pose complex management challenges. Surgical therapy is typically precluded owing to prohibitive mortality. The role of percutaneous mechanical circulatory support in such cases is well established; however, such interventions may be neither sufficient to achieve optimal stability nor prove definitive. The advent of novel catheter-based mitral repair modalities now offers primary decisive therapeutic intervention. Three cases of cardiogenic shock with severe MR illustrate the salutary hemodynamic and clinical responses to percutaneous mechanical support and valve repair by mitral clip.

Pathophysiology and Diagnosis of Pulmonary Hypertension Due to Left Heart Disease

Pulmonary hypertension due to left heart disease (PH-LHD) is the most common type of pulmonary hypertension, although an accurate prevalence is challenging. PH-LHD includes PH due to systolic or diastolic left ventricular dysfunction, mitral or aortic valve disease and congenital left heart disease. In recent years a new and distinct phenotype of “combined post-capillary and pre-capillary PH,” based on diastolic pulmonary gradient and pulmonary vascular resistance, has been recognized. The roles of right ventricular dysfunction and pulmonary vascular compliance in PH-LHD have also been elucidated recently and they appear to have significant clinical implications. Echocardiography continues to play a seminal role in diagnosis of PH-LHD and heart failure with preserved LV ejection fraction, as it can identify valve disease and help to distinguish PH-LHD from pre-capillary PH. Right, and occasionally left heart catheterization, remains the gold-standard for diagnosis and phenotyping of PH-LHD, although Cardiac Magnetic Resonance Imaging is emerging as a useful alternative tool in non-invasive diagnostic and prognostic assessment of PH-LHD. In this review, the latest evidence for more recent advances will be discussed, including the role of fluid challenge and exercise during cardiac catheterization to unravel occult post-capillary and the role of vasoreactivity testing. The use of many or all of these diagnostic techniques will undoubtedly provide key information about sub-groups of patients with PH-LHD that might benefit from medical therapy previously considered to be only suitable for pulmonary arterial hypertension.

Left atrial dilatation in systolic heart failure: a marker of poor prognosis, not just a buffer between the left ventricle and pulmonary circulation

BACKGROUND

The relation between systolic pulmonary pressure (sPAP) and left atrium in patients with heart failure (HF) is unclear. Diastolic dysfunction, expressed as restrictive mitral filling pattern (RMP), and functional mitral regurgitation (FMR) are associated with both LA enlargement and increased sPAP. We aimed to evaluate whether atrial dilation might modulate the consequences of RMP and FMR on the pulmonary circulation of patients with HF with reduced ejection fraction (HFrEF).

METHODS

1256 HFrEF patients were retrospectively recruited in four Italian centers. Left ventricular (LVD) and atrial (LAD) diameters were measure by m-mode, and EF were measured. RMP was defined as E-wave deceleration time lower than 140 ms. FMR was quantitatively measured. sPAP was evaluated based on maximal tricuspid regurgitant velocity and estimated right atrial pressure.

RESULTS

Final study population was formed by 1005 patients because of unavailability of sPAP in 252 patients. Mean EF was 33 ± 3, 35% had RMP, 67% had mild, and 26% moderate-to-severe FMR. 69% of patients had increased sPAP. A significant association was observed between sPAP and EF, RMP, FMR, and LAD (p < 0.0001 for all). At multivariate analysis, LAD was positively associated with sPAP (p < 0.0001) independently of EF, RMP, and FMR. Analogously, LAD (p < 0.05) was associated with more severe symptoms and worse prognosis after adjustment for LV function and FMR.

CONCLUSION

LA dilation was positively associated with sPAP independently of EF, RMP, and FMR. This highlights that LA size should be considered a marker of the severity of the disease.

Left atrial deformation: Useful index for early detection of cardiac damage in chronic mitral regurgitation

In chronic mitral regurgitation (MR) left atrium is one of the first cardiac structures that is involved in remodeling and ultrastructural changes for a progressive volume overload. Severe left atrial (LA) dilation on echocardiography and new onset of atrial fibrillation in asymptomatic patients with preserved Left Ventricular (LV) function, appeared as a Class IIb recommendation for consideration for surgical mitral valve repair in the actual guidelines. However, before atrial dilatation and dysfunction, several ultrastructural changes appear in the atrial muscle tissue that are difficult to identify with the standard echocardiography. Speckle tracking echocardiography (STE) can analyze LA function: it has been showed that it can indirectly identify structural tissue modifications from excessive atrial effort in the early stages of MR up to the full depression of atrial function in the late stages where there are advanced ultrastructural alterations. This review aims to summarize current knowledge on the role of atrial strain identifying early structural alterations of the atrial tissue in the rising stages of MR considering that Left Atrial Peak Longitudinal Strain (PALS) considered useful parameter for a more extensive evaluation of MR patients.

Left atrial volume index in patients with heart failure and severely impaired left ventricular systolic function: the role of established echocardiographic parameters, circulating cystatin C and galectin-3

Backround: Left atrial (LA) enlargement plays an important role in the development of heart failure (HF) and is a robust prognostic factor. Fibrotic processes have also been advocated to evoke HF through finite signalling proteins.

METHODS

We examined the association of two such proteins, cystatin C (CysC) and galectin-3 (Gal-3), and other clinical, echocardiographic and biochemical parameters with LA volume index (LAVi) in patients with HF with severely impaired left ventricular ejection fraction (LVEF). Severe renal, liver, autoimmune disease and cancer were exclusion criteria.

RESULTS

A total of 40 patients with HF (31 men, age 66.6 ± 1.7) with LVEF = 25.4 ± 0.9% were divided into two groups according to the mean LAVi (51.03 ± 2.9 ml/m2) calculated by two-dimensional transthoracic echocardiography. Greater LAVi was positively associated with LV end-diastolic volume ( p = 0.017), LV end-systolic volume ( p = 0.025), mitral regurgitant volume (MRV) ( p = 0.001), right ventricular systolic pressure (RVSP) ( p < 0.001), restrictive diastolic filling pattern ( p = 0.003) and atrial fibrillation ( p = 0.005). Plasma CysC was positively correlated with LAVi ( R2 = 0.135, p = 0.019) and log-transformed plasma Gal-3 ( R2 = 0.109, p = 0.042) by simple linear regression analysis. Stepwise multiple linear regression analysis showed that only MRV ( t = 2.236, p = 0.032), CysC ( t = 2.467, p = 0.019) and RVSP ( t = 2.155, p = 0.038) were significant predictors of LAVi.

CONCLUSIONS

Apart from known determinants of LAVi, circulating CysC and Gal-3 were associated with greater LA dilatation in patients with HF with reduced LVEF. Interestingly, the correlation between these two fibrotic proteins was positive.

Acute Changes in Left Atrial Pressure After MitraClip Are Associated With Improvement in 6-Minute Walk Distance

Background—

Data on the clinical use of left atrial (LA) hemodynamic monitoring during MitraClip procedure are limited. This study evaluated the association between intraprocedural changes in LA pressure after MitraClip and improvement in exercise capacity as documented by 6-minute walk test (6MWT).

Methods and Results—

Study population included 50 patients who underwent MitraClip at the Mayo Clinic (Rochester, MN), between June 2014 and July 2016 and completed both baseline and 30-day follow-up 6MWT. Primary outcome for the current analysis was defined as 6MWT improvement above the median. Mean age of the study population was 79±10 years, and 34 (68%) were men. Baseline preprocedural 6MWT distance was 308 m (interquartile range [IQR], 234–394 m). Acute, intraprocedural change in LA pressure after MitraClip was 3 mm Hg (IQR, 1–6 mm Hg), and change in V wave was 11 mm Hg (IQR, 6–19 mm Hg). Median 6MWT improvement was 25 m (IQR, 19–47 m). Univariate analysis showed that patients with ≤ mild postprocedural mitral regurgitation were 4-fold more likely to experience an improvement in 6MWT ( P =0.02). Multivariate model demonstrated that each 5 mm Hg decrease in V wave was associated with 49% increased likelihood for improvement in 6-minute walk ( P =0.04). Similar model with V-wave change as a dichotomous variable showed that patients with a V-wave decrease of ≥11 mm Hg were 3.8× more likely to improve their 6MWT ( P =0.05).

Conclusions—

Acute changes in LA pressure after MitraClip procedure are associated with clinical improvement as measured by 6MWT. Continuous LA pressure monitoring may be a useful tool for procedural guidance during transcatheter mitral repair.

Left atrial volume and function in dogs with naturally occurring myxomatous mitral valve disease

OBJECTIVE

Myxomatous mitral valve disease (MMVD) induces progressive left atrial (LA) enlargement. The LA modulates left ventricular filling and performance through its reservoir, conduit, and contractile function. Assessment of LA size and function may provide valuable information on the level of cardiac compensation. Left atrial function in dogs with naturally occurring MMVD remains largely unexplored. The objective of this study was to evaluate LA volume and function in dogs with naturally occurring MMVD.

ANIMALS

This prospective study included 205 client-owned dogs of different breeds, 114 healthy dogs, and 91 dogs with MMVD of different disease severities.

METHODS

Using two-dimensional echocardiography, the biplane area-length method was applied to assess LA volume and calculate volumetric indices of LA reservoir, conduit, and contractile function.

RESULTS

Left atrial volume and LA stroke volume increased, whereas LA reservoir and contractile function decreased with increasing disease severity. A maximal LA volume <2.25mL/kg was the optimal cut off identified for excluding congestive heart failure in dogs with chronic MMVD with a sensitivity of 96% and a specificity of 100%. An active LA emptying fraction <24% and/or a LA expansion index <126% were suggestive of congestive heart failure in dogs with chronic MMVD with a sensitivity of 77% and a specificity of 89% and a sensitivity of 82% and a specificity of 82%, respectively.

CONCLUSION

Dogs with MMVD appear to have larger LA volumes with poorer LA function. Deteriorating LA function, characterized by a decreasing reservoir and active contractile function, was evident in dogs with MMVD with increasing disease severity.

Left atrial volume index as an independent determinant of pulmonary hypertension in patients with chronic organic mitral regurgitation

BACKGROUND

The common pathophysiological consequences of chronic mitral regurgitation (MR) are left atrial (LA) remodeling/dilatation and pulmonary hypertension (PH). We aimed to study the association between LA volume (LAV) and PH in patients with chronic organic MR.

METHODS

We prospectively studied 154 patients (age 55.0 ± 16.4 years, 39.6 % female) with isolated moderate to severe chronic organic MR. Severity of MR was assessed using proximal isovelocity surface area method. LAV was assessed using the area-length biplane method. PH was defined as pulmonary artery systolic pressure > 50 mmHg.

RESULTS

Ruptured chordae and flail leaflets were the most common etiology of MR (53.2 %). Severe MR (effective regurgitant orifice area (EROA) > 40 mm(2)) was described in 123 (79.9 %) patients. Dyspnea, history of heart failure and atrial fibrillation was reported in 37.7 %, 20.1 % and 29.4 % of patients, respectively. Left ventricular (LV) ejection fraction was 68.1 ± 5.9 %. LAV index and EROA were 67.1 (24.7-391.3) ml/m(2)and 60.3 (10.5-250.9) mm(2), respectively. Age, presence of atrial fibrillation, EROA, LV end-systolic and end-diastolic volume, LV mass index, LAV index and tricuspid annular plane systolic excursion were all factors univariately associated with PH. In multiple logistic regression analysis, age (OR = 1.03, 95 % CI: 1.001-1.06, p = 0.04), EROA (OR = 1.02, 95 % CI: 1.003-1.03, p = 0.017) and LAV index (OR = 1.01, 95 % CI: 1.002-1.02, p = 0.021) were independently associated with PH.

CONCLUSIONS

In patients with chronic organic MR, a significant association exists between LAV index and PH. Age, the severity of MR as assessed by EROA, and LAV index are the independent determinants of PH.

Right atrial volume and reservoir function are novel independent predictors of clinical worsening in patients with pulmonary hypertension

BACKGROUND

Symptoms and signs and indices of right heart function are predictors of clinical outcomes in patients with pulmonary hypertension (PH). However, the significance of right atrial (RA) indices has not been sufficiently investigated. We investigated whether RA parameters predict outcomes in patients with pre-capillary PH.

METHODS

Study subjects were 68 patients with pre-capillary PH. RA size and function (systolic, reservoir, and conduit functions) were evaluated by cardiac magnetic resonance imaging.

RESULTS

During the mean follow-up period of 24 months, 16 of 68 patients experienced clinical worsening (CW), defined as hospitalization because of right heart failure, lung transplantation, or PH-related death. Kaplan-Meier and log-rank test showed that World Health Organization functional class, pericardial effusion, increased brain natriuretic peptide concentration, reduced right ventricular ejection fraction (RVEF), increased minimum RA volume index, and decreased RA reservoir volume were associated with CW-free survival. The combination of RVEF and RA reservoir function was a better predictor of CW-free survival. In univariate Cox hazard proportional analysis, CW was associated with the RA reservoir volume index (hazard ratio [HR] = 0.80). In multivariate analysis, CW was associated with World Health Organization functional class (HR = 4.3), RA minimum volume index (HR = 1.07), and RA reservoir volume index (HR = 0.73).

CONCLUSIONS

RA volume and reservoir function and their combined use with RVEF are novel predictors of CW in patients with pre-capillary PH.

Preoperative left ventricular ejection fraction and left atrium reverse remodeling after mitral regurgitation surgery

Background

Left atrium enlargement has been associated with cardiac events in patients with mitral regurgitation (MR). Left atrium reverse remodeling (LARR) occur after surgical correction of MR, but the preoperative predictors of this phenomenon are not well known. It is therefore important to identify preoperative predictors for postoperative LARR.

Methods

We enrolled 62 patients with chronic severe MR (prolapse or flail leaflet) who underwent successful mitral valve surgery (repair or replacement); all with pre- and postoperative echocardiography. LARR was defined as a reduction in left atrium volume index (LAVI) of ≥25%. Stepwise multiple regression analysis was used to identify independent predictors of LARR.

Results

LARR occurred in 46 patients (74.2%), with the mean LAVI decreasing from 85.5 mL/m² to 49.7 mL/m² (p <0.001). These patients had a smaller preoperative left ventricular systolic volume (p =0.022) and a higher left ventricular ejection fraction (LVEF) (p =0.034). LVEF was identified as the only preoperative variable significantly associated with LARR (odds ratio, 1.086; 95% confidence interval, 1.002–1.178). A LVEF cutoff value of 63.5% identified patients with LARR of ≥25% with a sensitivity of 71.7% and a specificity of 56.3%.

Conclusions

LARR occurs frequently after mitral valve surgery and is associated with preoperative LVEF higher than 63.5%.

Left atrial eccentricity in chronic mitral regurgitation: relation to left atrial function

AIMS

The aim of this study was to assess the changes in the left atrial (LA) shape and to identify the determinants of these changes in chronic mitral regurgitation (MR).

METHODS AND RESULTS

We enrolled 125 consecutive patients (56 ± 16 years, 51% men) with chronic MR caused by myxomatous mitral valve disease in sinus rhythm and 45 control patients (54 ± 15 years, 55% men) undergoing transthoracic Doppler echocardiography. The LA eccentricity index (LAEi) and the LA volume index (LAVi) were used to estimate the LA shape and size, respectively. There were significant decreases in LAEi (r= -0.723, P< 0.001) and increases in LAVi (r= 0.642, P< 0.001) with increasing severity of MR. In multivariate stepwise linear regression analysis, regurgitant fraction (RF) was an independent determinant of the LAE, whereas RF, left ventricular (LV) mass index and LV diastolic dysfunction grade were independent determinants of the LA volume. The LAEi was positively related to the velocity of A' in the entire population (r = 0.238, P = 0.002). On the receiver operating characteristic (ROC) curve analysis, LAEi ≤1.30 was the best cut-off value to reflect the LA systolic dysfunction (A' velocity <7 cm/s; area under the curve was 0.78, P < 0.001).

CONCLUSION

LA becomes more spherical with increasing severity of MR, suggesting a decrease in LAE, which is mainly determined by the volume overload. LAE might be closely related to the LA systolic function in chronic MR.

Contemporary application of cardiovascular hemodynamics: transcatheter mitral valve interventions

Since the development and refinement of echocardiography, this technique has, for some time, been the mainstay for hemodynamic assessment of the mitral valve. This article discusses the key components of the invasive hemodynamic assessment of mitral valve disease and illustrates their utility through percutaneous transluminal mitral valvuloplasty for mitral stenosis and the novel transcatheter mitral valve repair using the MitraClip for mitral regurgitation. Changes in left atrial pressure and waveform, mean gradient, and cardiac output are critical assessment parameters for both safety and efficacy. Invasive hemodynamic assessment is an essential complement to echocardiography for the optimal guidance of these procedures.

Left atrial reverse remodeling and functional improvement after mitral valve repair in degenerative mitral regurgitation: a real-time 3-dimensional echocardiography study

BACKGROUND

Severe mitral regurgitation is often associated with left atrium (LA) enlargement, which is a well-known predictor of adverse cardiovascular outcomes. However, only few data are available on the effect of mitral valve (MV) repair on LA size. The aim of this study was to evaluate, using real-time 3-dimensional echocardiography, the changes in LA volumes after MV repair.

METHODS

A total of 65 patients with severe mitral regurgitation due to MV prolapse and scheduled for repair at an early stage were enrolled. Before the procedure, real-time 3-dimensional echocardiography was performed to assess LA volumes (maximum, before atrial active contraction [preA], and minimum). The same evaluation was repeated 6 months and 1 year after MV repair. Twenty healthy subjects matched for age and gender were enrolled as a control group.

RESULTS

Before MV repair, patients showed significantly higher values of LA volumes (maximum 43 ± 14 mL/m², preA 33 ± 12 mL/m², minimum 23 ± 11 mL/m²) as compared to controls (maximum 22 ± 6 mL/m², preA 13 ± 4 mL/m², minimum 8 ± 3 mL/m²). Six months after the operation, LA volumes significantly decreased (maximum 25 ± 8 mL/m², preA 18 ± 8 mL/m², minimum 13 ± 5 mL/m²), with a further reduction at 1-year follow-up (maximum 23 ± 7 mL/m², preA 15 ± 7 mL/m², minimum 11 ± 5 mL/m²), resulting in values similar to controls. The extent of LA reverse remodeling was inversely correlated with age (r = -0.42) and postoperative transmitral mean pressure gradient (r = -0.32), whereas a positive correlation was found with the reduction in left ventricular volume after MV repair (r = 0.35).

DISCUSSION

In patients with severe mitral regurgitation due to MV prolapse, MV repair, when performed at an early stage, results in a significant LA reverse remodeling.

Cardiopulmonary Exercise Testing Determination of Functional Capacity in Mitral Regurgitation

OBJECTIVES

This study was designed to evaluate prevalence, determinants, and clinical outcome implications of reduced functional capacity (FC) in patients with organic mitral regurgitation (MR).

BACKGROUND

Evaluation of FC by exercise testing is rarely performed in MR because little is known about the clinical determinants and outcome implications of FC.

METHODS

Cardiopulmonary exercise testing (CPET) was prospectively performed in 134 asymptomatic patients with organic MR to assess FC (peak oxygen consumption [VO2]) simultaneously to Doppler-echocardiographic quantitation of MR (effective regurgitant orifice [ERO]) and left ventricular (LV) systolic and diastolic function.

RESULTS

Peak VO2 was 26 +/- 6 ml/kg/min (96 +/- 16% of age-predicted), but varied widely (57% to 145% of predicted) and was markedly reduced (< or =84% of predicted) in 19% of patients. Although ERO of MR was univariately associated with reduced FC (26 vs. 9% with ERO > or =40 vs. <40 mm2), independent determinants of reduced FC were LV diastolic function (higher E/E' ratio, p = 0.006), atrial fibrillation (p = 0.01), and lower forward stroke volume (p = 0.03). Clinical events (death, heart failure, new atrial fibrillation) and clinical events or surgery were more frequent with than without reduced FC (3 years, 36 +/- 14% vs. 13 +/- 4%, p = 0.02; and 66 +/- 11% vs. 29 +/- 5%, p = 0.001, respectively), even adjusting (risk ratios 1.80 and 1.54 respectively, both p < or = 0.03) for age and ERO.

CONCLUSIONS

In asymptomatic organic MR, FC quantitatively assessed by CPET is unexpectedly markedly reduced in one out of every four to five patients. Reduced FC is independently determined by consequences rather than severity of MR and predicts increased subsequent clinical events. Therefore, CPET frequently reveals functional limitations not detected clinically and is an important tool in managing patients with organic MR.

Quantitative determinants of the outcome of asymptomatic mitral regurgitation

BACKGROUND

The clinical outcome of asymptomatic mitral regurgitation is poorly defined, and the treatment is uncertain. We studied the effect on the outcome of quantifying mitral regurgitation according to recent guidelines.

METHODS

We prospectively enrolled 456 patients (mean [+/-SD] age, 63+/-14 years; 63 percent men; ejection fraction, 70+/-8 percent) with asymptomatic organic mitral regurgitation, quantified according to current recommendations (regurgitant volume, 66+/-40 ml per beat; effective regurgitant orifice, 40+/-27 mm2).

RESULTS

The estimated five-year rates (+/-SE) of death from any cause, death from cardiac causes, and cardiac events (death from cardiac causes, heart failure, or new atrial fibrillation) with medical management were 22+/-3 percent, 14+/-3 percent, and 33+/-3 percent, respectively. Independent determinants of survival were increasing age, the presence of diabetes, and increasing effective regurgitant orifice (adjusted risk ratio per 10-mm2 increment, 1.18; 95 percent confidence interval, 1.06 to 1.30; P<0.01), the predictive power of which superseded all other qualitative and quantitative measures of regurgitation. Patients with an effective regurgitant orifice of at least 40 mm2 had a five-year survival rate that was lower than expected on the basis of U.S. Census data (58+/-9 percent vs. 78 percent, P=0.03). As compared with patients with a regurgitant orifice of less than 20 mm2, those with an orifice of at least 40 mm2 had an increased risk of death from any cause (adjusted risk ratio, 2.90; 95 percent confidence interval, 1.33 to 6.32; P<0.01), death from cardiac causes (adjusted risk ratio, 5.21; 95 percent confidence interval, 1.98 to 14.40; P<0.01), and cardiac events (adjusted risk ratio, 5.66; 95 percent confidence interval, 3.07 to 10.56; P<0.01). Cardiac surgery was ultimately performed in 232 patients and was independently associated with improved survival (adjusted risk ratio, 0.28; 95 percent confidence interval, 0.14 to 0.55; P<0.01).

CONCLUSIONS

Quantitative grading of mitral regurgitation is a powerful predictor of the clinical outcome of asymptomatic mitral regurgitation. Patients with an effective regurgitant orifice of at least 40 mm2 should promptly be considered for cardiac surgery.

[Physiopathology and etiology of mitral insufficiency]

Mitral regurgitation has a complex pathophysiology. It should be assessed from the study of factors influencing regurgitant volume and the evaluation of hemodynamics effects downstream (impact on left ventricular function) and upstream (level of left atrial compliance and pulmonary pressure). The regurgitant volume is larger when the regurgitation time is longer, the regurgitant orifice is bigger and the magnitude of the left ventrico-atrial systolic gradient higher. The study of left ventricular function is difficult, especially in chronic mitral regurgitation where the apparently normal left ventricular systolic function can hide a significant worsening in myocardiacs fibres contractile abilities. With the increase in life expectancy and with the decrease in the incidence of rheumatic fever, aetiologies of mitral regurgitation have changed in the past 30 years. They are now dominated by dystrophic mitral regurgitation and infective endocarditis while rheumatic fever becomes less frequent.