Causes and mechanisms of isolated mitral regurgitation in the community: clinical context and outcome

AIMS

To define the hitherto unknown aetiology/mechanism distributions of mitral regurgitation (MR) in the community and the linked clinical characteristics/outcomes.

METHODS AND RESULTS

We identified all isolated, moderate/severe MR diagnosed in our community (Olmsted County, MN, USA) between 2000 and 2010 and classified MR aetiology/mechanisms. Eligible patients (n = 727) were 73 ± 18 years, 51% females, with ejection fraction (EF) 49 ± 17%. MR was functional (FMR) in 65%, organic (OMR) in 32% and 2% mixed. Functional MR was linked to left ventricular remodelling (FMR-v) 38% and isolated atrial dilatation (FMR-a) 27%. At diagnosis FMR-v vs. FMR-a, vs. OMR displayed profound differences (all P < 0.0001) in age (73 ± 14, 80 ± 10, 68 ± 21years), male-sex (59, 33, 51%), atrial-fibrillation (28, 54, 13%), EF (33 ± 14, 57 ± 11, 61 ± 10%), and regurgitant-volume (38 ± 13, 37 ± 11, 51 ± 24 mL/beat). Dominant MR mechanism was Type I (normal valve-movement) 38%, Type II (excessive valve-movement) 25%, Type IIIa (diastolic movement-restriction) 3%, and Type IIIb (systolic movement-restriction) 34%. Outcomes were mediocre with excess-mortality vs. general-population in FMR-v [risk ratio 3.45 (2.98-3.99), P < 0.0001] but also FMR-a [risk ratio 1.88 (1.52-2.25), P < 0.0001] and OMR [risk ratio 1.83 (1.50-2.22), P < 0.0001]. Heart failure was frequent, particularly in FMR-v (5-year 83 ± 3% vs. 59 ± 4% FMR-a, 40 ± 3% OMR, P < 0.0001). Mitral surgery during patients' lifetime was performed in 4% of FMR-v, 3% of FMR-a, and 37% of OMR.

CONCLUSION

Moderate/severe isolated MR in the community displays considerable aetiology/mechanism heterogeneity. Functional MR dominates, mostly FMR-v but FMR-a is frequent and degenerative MR dominates OMR. Outcomes are mediocre with excess-mortality particularly with FMR-v but FMR-a, despite normal EF incurs notable excess-mortality and frequent heart failure. Pervasive undertreatment warrants clinical trials of therapies tailored to specific MR cause/mechanisms.

Contemporary differences between bicuspid and tricuspid aortic valve in chronic aortic regurgitation

OBJECTIVE

To comprehensively explore contemporary differences between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) patients with chronic haemodynamically significant aortic regurgitation (AR).

METHODS

Consecutive patients with chronic ≥moderate-severe AR from a tertiary referral centre (2006-2017) were included. All-cause mortality, surgical indications and aortic valve surgery (AVS) were analysed.

RESULTS

Of 798 patients (296 BAV-AR, age 46±14 years; 502 TAV-AR, age 67±14 years, p<0.0001) followed for 5.5 (IQR: 2.9-9.2) years, 403 underwent AVS (repair in 96) and 154 died during follow-up. The 8-year AVS incidence was 60%±3% versus 53%±3% for BAV-AR and TAV-AR, respectively (p=0.014). The unadjusted (real-life) 8-year total survival was 93%±7% versus 71%±2% for BAV-AR and TAV-AR, respectively (p<0.0001), and became statistically insignificant after sole adjustment for age (p=0.14). The within-group relative risk of death in BAV-AR patients demonstrated a large age-dependent increase (two fold at 50-55 years, up to 10-fold at 70 years). The presence of baseline symptoms was significantly associated with death for both BAV-AR (p=0.039) and TAV-AR (p<0.0001), but the strength of the association decreased with age adjustment for BAV-AR (age-adjusted HR 2.43 (0.92-6.39), p=0.07) and not for TAV-AR (age-adjusted HR, 2.3 (1.6-3.3), p<0.0001). As compared with general population, TAV-AR exhibited baseline excess risk which further increased at left ventricular ejection fraction (LVEF) <60% and left ventricular end-systolic dimension index (LVESDi) >20 mm/m²; similar thresholds were observed for BAV-AR patients.

CONCLUSION

BAV-AR patients were two decades younger than TAV-AR and underwent AVS more frequently, resulting in a considerable real-life survival advantage for BAV-AR that was determined primarily by age and not valve anatomy. Pragmatically, regardless of valve anatomy, patients with haemodynamically significant AR and age >50-55 years require a low-threshold for surgical referral to prevent symptom development where LVEF <60% and LVESDi >20 mm/m² seem appropriate referral thresholds.

Mitral Valve Prolapse Patients with Less than Moderate Mitral Regurgitation Exhibit Early Cardiac Chamber Remodeling

BACKGROUND

Mild physiologic mitral regurgitation (MR) is common in normal individuals. Patients with primary MR due to mitral valve prolapse (MVP) may also exhibit less than moderate MR. We sought to determine whether MVP patients with less than moderate MR displayed early cardiac chamber remodeling or factors related to early remodeling and whether early remodeling predicted MR progression.

METHODS

Consecutive MVP patients with less than moderate MR by proximal isovelocity surface area-derived effective regurgitant orifice < 20 mm2 and regurgitant volume < 30 mL, were matched for age and sex with non-MVP patients (controls) having less than moderate MR. Patients with moderate or greater dysfunctional left- or right-sided valves and left ventricular ejection fraction < 50% were excluded. We evaluated left ventricle (LV) and left atrium (LA) remodeling parameters (LV end-diastolic and end-systolic indexed diameters, LA volume-index, and LV mass-index) as well as determinants of remodeling. The last available transthoracic echocardiography was reviewed to identify progression to moderate-severe MR or more.

RESULTS

A total of 253 MVP patients with less than moderate MR were matched to 344 controls (P for age and sex, ≥.18) with less than moderate MR. Patients with MVP (mean effective regurgitant orifice and regurgitant volume, 12 ± 4 mm2 and 18 ± 6 mL, respectively) had more premature ventricular contractions (PVCs), larger LV and LA remodeling parameters, and more mild-to-moderate MR (all P < .0001). Multivariate linear regression models showed that larger LV remodeling parameters were independently associated with MVP and female sex but not MR severity (all P < .0001). The LA volume index was independently associated with MVP, age, and E/e' (all P < .0001). The LV mass index was associated with MVP, age, and hypertension (all P ≤ .002). Presence of PVCs was associated with LV end-systolic diameter ≥ 40 mm and indexed ≥ 22 mm2 (P = .005). Among 323 (54%) patients having subsequent transthoracic echocardiography, 17 patients (all MVP) progressed to moderate-severe MR or more at a median of 4.3 (interquartile range, 1.7-6.4) years. Isolated posterior leaflet prolapse was the single factor associated with MR progression (adjusted hazard ratio, 2.70; 95% CI, 0.99-7.34; P = .048) after adjustment for MR severity. At a median of 5.9 (interquartile range, 4.6-7.2) years of follow-up, female sex and MVP (vs controls) were protective factors for mortality.

CONCLUSIONS

Patients with less than moderate MR due to MVP exhibit early LV and LA remodeling, which does not predict MR progression or mortality. Left ventricle remodeling is associated with MVP, female sex, and presence of PVCs. Early chamber remodeling associated with MVP may be the phenotypical expression of a genetically mediated process and is at least partially related to PVCs.

Speaking a common language: Introduction to a standard terminology for the bicuspid aortic valve and its aortopathy

There is a growing need to develop a common language when referring to a frequent and heterogeneous condition such as the congenital bicuspid aortic valve and its aortopathy. The following short manuscript serves as an introduction to a standard terminology for the bicuspid aortic valve and its aortopathy.

650The arrhythmic mitral valve prolapse: presentation and outcome

Background

The majority of patients with of Mitral-valve-prolapse (MVP) have a excellent prognosis. Until recently most cases of mortality were thought to be related to mitral regurgitation and left ventricular dysfunction. The concept of the arrhythmic MVP emerged to describe cases of sudden cardiac death (SCD) in the presence of isolated MVP yet it’s phonotype remains incompletely and inconsistently defined.

Purpose

To analyze the prevalence, severity and characteristics of ventricular-arrhythmia (VA), to determine it’s phenotypical context and independent impact on outcome in patients with MVP.

Methods

A cohort of 595 (65 ± 16 years, 278 female) consecutive patients with MVP and comprehensive clinical, arrhythmia (24hour-Holter) and Doppler-echocardiographic characterization, was identified and long-term outcome analyzed.

Results

VA was frequent, present in 43% of patients with at least ventricular ectopy≥5%, but was most often moderate (ventricular-tachycardia—VT 120-179bpm) in 27% and rarely severe (VT≥180/min) in 8.6%.  Presence of VA was associated with older age, male sex, bileaflet-prolapse, marked leaflet redundancy, mitral-annulus-disjunction (MAD), larger left-atrium and left ventricular end-systolic diameter, and T-wave-inversion/ST-depression (all P ≤ 0.001).  Severe VA was independently associated with presence of MAD, leaflet-redundancy and T-wave-inversion/ST-depression (all P &lt; 0.0001) but not with mitral regurgitation severity or ejection-fraction.  Outcome primary endpoint of overall survival after arrhythmia diagnosis (8-year 87 ± 2%) was strongly associated with arrhythmia-severity (8-year 90 ± 2% for no/trivial arrhythmia, 85 ± 3% for mild/moderate and 76 ± 7% for severe arrhythmia. P = 0.02, Figure). Excess-mortality was substantial for severe-arrhythmia (univariate-hazard-ratio 2.70[1.27-5.77], P = 0.01 vs. no/trivial arrhythmia), even adjusted comprehensively including for MVP-characteristics (adjusted-hazard-ratio 2.94[1.36-6.36], P = 0.006) ). 

Conclusions

This large cohort of isolated consecutive MVP characterized with 24-hour-Holter monitoring, clinical and Echocardiographic assessment, demonstrates that VA are frequent with MVP but rarely severe. The arrhythmic MVP was independently and strongly associated with specific ECG and morphologic patterns, particularly ST-T changes, MAD presence and marked leaflet redundancy, suggestive of a specific arrhythmic MVP phenotype, independently of MR-severity. Arrhythmia, particularly severe, is associated with long-term excess-mortality, independently of any other characteristics, including MR severity and LVEF. These findings lay the foundation for novel risk-stratification of MVP for the conduct of prospective controlled studies evaluating the management of MVP high-risk patients.

Figure – Impact on survival of ventricular arrhythmia

Overall survival of MVP stratified by ventricular arrhythmia (Panel A) or ventricular arrhythmia severity (Panel B) throughout follow-up.

Abstract Figure.

Functional tricuspid regurgitation of degenerative mitral valve disease: a crucial determinant of survival

Aims 

To assess functional tricuspid regurgitation (FTR) determinants, consequences, and independent impact on outcome in degenerative mitral regurgitation (DMR).

Methods and results 

All patients diagnosed with isolated DMR 2003–2011, with structurally normal tricuspid leaflets, prospective FTR grading and systolic pulmonary artery pressure (sPAP) estimation by Doppler echocardiography at diagnosis were identified and long-term outcome analysed. The 5083 DMR eligible patients [63 ± 16 years, 47% female, ejection fraction (EF) 63 ± 7%, and sPAP 35 ± 13 mmHg] presented with FTR graded trivial in 45%, mild in 37%, moderate in 15%, and severe in 3%. While pulmonary hypertension (PHTN-sPAP ≥ 50 mmHg) was the most powerful FTR severity determinant, other strong FTR determinants were older age, female sex, lower left ventricle EF, DMR, and particularly atrial fibrillation (AFib) (all P ≤ 0.002). Functional tricuspid regurgitation moderate/severe was independently linked to more severe clinical presentation, more oedema, lower stroke volume, and impaired renal function (P ≤ 0.01). Survival (95% confidence interval) throughout follow-up [70% (69–72%) at 10 years] was strongly associated with FTR severity [82% (80–84%) for trivial, 69% (66–71%) for mild, 51% (47–57%) for moderate, and 26% (19–35%) for severe, P &lt; 0.0001]. Excess mortality persisted after comprehensive adjustment [adjusted hazard ratio 1.40 (1.18–1.67) for moderate FTR and 2.10 (1.63–2.70) for severe FTR, P ≤ 0.01]. Excess mortality persisted adjusting for sPAP/right ventricular function (P &lt; 0.0001), by matching [adjusted hazard ratios 2.08 (1.50–2.89), P &lt; 0.0001] and vs. expected survival [risk ratio 1.79 (1.48–2.16), P &lt; 0.0001]. Within 5-year of diagnosis valve surgery was performed in 73% (70–75%) and 15% (13–17%) of severe and moderate DMR and in only 26% (19–34%) and 6% (4–8%) of severe and moderate FTR. Valvular surgery improved outcome without alleviating completely higher mortality associated with FTR (P &lt; 0.0001).

Conclusion 

In this large DMR cohort, FTR was frequent and causally, not only linked to PHTN but also to other factors, particularly AFib. Higher FTR severity is associated at diagnosis with more severe clinical presentation. Long term, FTR is independently of all confounders, associated with considerably worse mortality. Functional tricuspid regurgitation moderate and even severe is profoundly undertreated. Thus careful assessment, consideration for tricuspid surgery, and testing of new transcatheter therapy is warranted.

Outcomes From Transcatheter Aortic Valve Replacement in Patients With Low-Flow, Low-Gradient Aortic Stenosis and Left Ventricular Ejection Fraction Less Than 30%: A Substudy From the TOPAS-TAVI Registry

Importance

In low-flow, low-gradient aortic stenosis (LFLG AS), the severity of left ventricular dysfunction remains a key factor in the evaluation of aortic valve replacement.

Objective

To evaluate the clinical outcomes and changes in left ventricular ejection fraction (LVEF) after transcatheter aortic valve replacement (TAVR) in patients with LFLG AS and severe left ventricular dysfunction.

Design, Setting, and Participants

This multicenter registry is a substudy of the True or Pseudo-Severe Aortic Stenosis-TAVI registry that included patients with classic LFLG AS, defined as a mean transvalvular gradient less than 35 mm Hg, an effective orifice area less than 1.0 cm2, and an LVEF of 40% or less. Patients were divided in groups with very low (<30%) LVEF and low (30%-40%) LVEF. Dobutamine stress echocardiography (DSE) was performed before TAVR in a subset with very low LVEF, and presence of contractile reserve was defined as an increase of 20% or more in stroke volume. Clinical outcomes were assessed at 1 and 12 months and yearly thereafter, and echocardiography was performed at 1-year follow-up. Retrospective data were collected from 2007 to 2013 and prospective data from January 2013 to March 2018. Data were analyzed from March to October 2018.

Exposures

Transcatheter aortic valve replacement in patients with LFLG AS.

Main Outcomes and Measures

Changes in LVEF over time; periprocedural and late mortality.

Results

A total of 293 patients were included, including 128 (43.7%) with very low LVEF and 165 with low LVEF (56.3%). Their mean (SD) age was 80 (7) years, and most (214 [73.0%]) were men. The mean (SD) LVEF in the very low LVEF group was 22% (5%), compared with 37% (7%) in the low LVEF group (P < .001). There were no differences between groups in rates of periprocedural mortality and late mortality (median [interquartile range], 23 [6-38] months). Patients with very low LVEF displayed a greater increase in LVEF at the 1-year follow-up examination (mean absolute increase, 11.9% [95% CI, 8.8%-15.1%]), than the low LVEF group (3.6% [95% CI, 1.1%-6.1%]; P < .001). In 92 patients with very low LVEF who had preprocedural DSE, results showed a lack of contractile reserve in 45 (49%), but this had no effect on clinical outcomes or changes in LVEF over time.

Conclusions and Relevance

In patients with LFLG AS and severe left ventricular dysfunction, TAVR was associated with similar clinical outcomes as in counterparts with milder left ventricular dysfunction. The TAVR procedure was associated with a significant increase in LVEF, irrespective of contractile reserve. These results support TAVR for LFLG AS, irrespective of the severity of left ventricular dysfunction and DSE results.

The MIDA Mortality Risk Score: development and external validation of a prognostic model for early and late death in degenerative mitral regurgitation

Aims

In degenerative mitral regurgitation (DMR), lack of mortality scores predicting death favours misperception of individual patients' risk and inappropriate decision-making.

Methods and results

The Mitral Regurgitation International Database (MIDA) registries include 3666 patients (age 66 ± 14 years; 70% males; follow-up 7.8 ± 5.0 years) with pure, isolated, DMR consecutively diagnosed by echocardiography at tertiary (European/North/South-American) centres. The MIDA Score was derived from the MIDA-Flail-Registry (2472 patients with DMR and flail leaflet-Derivation Cohort) by weighting all guideline-provided prognostic markers, and externally validated in the MIDA-BNP-Registry (1194 patients with DMR and flail leaflet/prolapse-Validation Cohort). The MIDA Score ranged from 0 to 12 depending on accumulating risk factors. In predicting total mortality post-diagnosis, the MIDA Score showed excellent concordance both in Derivation Cohort (c = 0.78) and Validation Cohort (c = 0.81). In the whole MIDA population (n = 3666 patients), 1-year mortality with Scores 0, 7-8, and 11-12 was 0.4, 17, and 48% under medical management and 1, 7, and 14% after surgery, respectively (P < 0.001). Five-year survival with Scores 0, 7-8, and 11-12 was 98 ± 1, 57 ± 4, and 21 ± 10% under medical management and 99 ± 1, 82 ± 2, and 57 ± 9% after surgery (P < 0.001). In models including all guideline-provided prognostic markers and the EuroScoreII, the MIDA Score provided incremental prognostic information (P ≤ 0.002).

Conclusion

The MIDA Score may represent an innovative tool for DMR management, being able to position a given patient within a continuous spectrum of short- and long-term mortality risk, either under medical or surgical management. This innovative prognostic indicator may provide a specific framework for future clinical trials aiming to compare new technologies for DMR treatment in homogeneous risk categories of patients.

How Should Very Severe Aortic Stenosis Be Defined in Asymptomatic Individuals?

See Article by Kanamori et al.

P6474Hidden in plain sight: diastolic blood pressure, resting heart rate and physical examination are independent predictors of mortality in chronic aortic regurgitation

Background

In patients with hemodynamically-significant chronic aortic valve regurgitation (AR), the prognostic significance of routinely-measured diastolic blood pressure (DBP), resting heart rate (RHR) and physical examination signs of heart failure (HF), is unknown.

Purpose

To investigate the association of DBP, RHR and HF signs, with all-cause mortality.

Methods

This retrospective cohort study included all consecutive patients with moderately-severe or severe AR within a tertiary-referral center from 2006–2017. Patients with ≥moderate aortic stenosis and those with ≥moderate mitral stenosis/regurgitation were excluded.

Results

Of 820 patients (age 59±17 years; 82% men) with DBP 64±13mmHg and RHR 64±12bpm, followed for 5.5±3.5 years, 104 died under medical management and 400 underwent aortic valve surgery (AVS). In multivariable analysis, DBP (adjusted-hazard ratio [HR] 0.82 [0.68–0.98] p=0.031, per 10mmHg increase), RHR (adjusted HR 1.2 [1.01–1.41] p=0.034 per 10bpm increase), and any HF signs (adjusted HR 1.66 [1.04–2.61] p=0.032) were associated with all-cause death independently of demographics, comorbidities, and guideline-derived surgical triggers. Mortality increased in a J-curve fashion for DBP starting at 70 mmHg and peaking at 55 mmHg (Fig A,C), and in a linear fashion for RHR starting at 60bpm (Fig B, D). The association persisted after additional adjustment for medications, presence of hypertension and time-dependent AVS. A clinical score combining DBP, RHR and any HF signs increased the mortality risk-discrimination of demographics and comorbidities from 74% to 79% (p=0.01), and from 79% to 82% after addition of surgical triggers (p=0.04).

Figure. Risk of death by DBP and RHR

Conclusions

In patients with AR, routinely-measured vital signs and physical examination are strongly associated with all-cause mortality; lower DBP, higher RHR and any HF signs are independent predictors of mortality, and provide incremental mortality risk-discriminating value to baseline demographics, comorbidities and guideline-derived surgical triggers. These findings represent a clinical paradigm shift and have guideline implications.

The unique mechanism of functional mitral regurgitation in acute myocardial infarction: a prospective dynamic 4D quantitative echocardiographic study

AIMS

Mechanisms of chronic ischaemic mitral regurgitation (IMR) are well-characterized by apically tethered leaflet caused by papillary muscles (PMs) displacement and adynamic mitral apparatus. We investigated the unique geometry and dynamics of the mitral apparatus in first acute myocardial infarction (MI) by using quantified 3D echocardiography.

METHODS AND RESULTS

We prospectively performed 3D echocardiography 2.3 ± 1.8 days after first MI, in 174 matched patients with (n = 87) and without IMR (n = 87). 3D echocardiography of left ventricular (LV) volumes and of mitral apparatus dynamics throughout cardiac cycle was quantified. Similar mitral quantification was obtained at chronic post-MI stage (n = 44). Mechanistically, acute IMR was associated with larger and flatter annulus (area 9.29 ± 1.74 cm2 vs. 8.57 ± 1.94 cm2, P = 0.002, saddle shape 12.7 ± 4.5% vs. 15.0 ± 4.6%, P = 0.001), and larger tenting (length 6.36 ± 1.78 mm vs. 5.60 ± 1.55 mm, P = 0.003) but vs. chronic MI, mitral apparatus displayed smaller alterations (all P < 0.01) and annular size, PM movement remained dynamic (all P < 0.01). Specific to acute IMR, without PM apical displacement (P > 0.70), greater separation (21.7 ± 4.9 mm vs. 20.0 ± 3.4 mm, P = 0.01), and widest angulation of PM (38.4 ± 6.2° for moderate vs. 33.5 ± 7.3° for mild vs. 31.4 ± 6.3° for no-IMR, P = 0.0009) wider vs. chronic MI (P < 0.01).

CONCLUSIONS

3D echocardiography of patients with first MI provides insights into unique 4D dynamics of the mitral apparatus in acute IMR. Mitral apparatus remained dynamic in acute MI and distinct IMR mechanism in acute MI is not PM displacement seen in chronic IMR but separation and excess angulation of PM deforming the mitral valve, probably because of sudden-onset regional wall motion abnormality without apparent global LV remodelling. This specific mechanism should be considered in novel therapeutic strategies for IMR complicating acute MI.