Functional mitral regurgitation in patients with aortic stenosis: prevalence, clinical correlates and pathophysiological determinants: a quantitative prospective study

Multiple Valvular Heart Disease in the Transcatheter Era: A State-of-the-Art Review

Although existing guidelines offer strong recommendations for single valvular dysfunction, the growing prevalence of multiple valvular heart disease (MVHD) in our aging population is challenging the clarity of clinical guidance. Traditional diagnostic modalities, such as echocardiography, face inherent constraints in precisely quantifying valvular dysfunction due to the hemodynamic interactions that occur with multiple valve involvement. Therefore, many patients with MVHD present at a later stage in their disease course and with an elevated surgical risk. The expansion of transcatheter therapy for the treatment of valvular heart disease has added new opportunities for higher-risk patients. However, the impact of isolated valve therapies on patients with MVHD is still not well understood. This review focuses on the etiology, diagnostic challenges, and therapeutic considerations for some of the most common concomitant valvular abnormalities that occur in our daily clinic population.

Perspectives on Secondary Mitral Regurgitation in Heart Failure

PURPOSE OF THE REVIEW

This review focuses on broader perspectives of mitral regurgitation (MR) in patients with heart failure.

RECENT FINDINGS

The ratio of regurgitant volume to end-diastolic volume appears to help identify patients who may benefit from valve interventions. Secondary MR is not only attributed to geometric changes of the LV but also related to the structural changes in the mitral valve that include fibrosis of the mitral leaflets and changes in the extracellular matrix. The transition from mild to severe secondary MR can occur at different rates, from a slow LV remodeling process to a more abrupt process precipitated by an inciting event such as atrial fibrillation. Septal flash and apical rocking, two new visual markers of LV mechanical dyssynchrony, appear to be predictive of MR reduction following cardiac resynchronization therapy. Optimal guideline-directed medical therapy has been shown to decrease the severity of secondary MR effectively. A theoretical framework to characterize secondary MR as it relates to the onset of MR is proposed. Type A: Early onset of MR contemporaneous with myocardial injury. The maladaptive LV remodeling occurs in parallel with MR. Type B: LV remodeling proceeds without significant MR until the LV is moderately dilated, which coincides with or without inciting factors such as atrial fibrillation. Type C: LV remodeling proceeds after myocardial injury without significant MR until the LV is severely dilated. MR is a late manifestation of LV remodeling.

Beyond Aortic Stenosis: Addressing the Challenges of Multivalvular Disease Assessment

Aortic stenosis (AS) can often coexist with other valvular diseases or be combined with aortic regurgitation (AR), leading to unique pathophysiological conditions. The combination of affected valves can vary widely, resulting in a lack of standardized diagnostic or therapeutic approaches. Echocardiography is crucial in assessing patients with valvular heart disease (VHD), but careful consideration of the hemodynamic interactions between combined valvular defects is necessary. This is important as it may affect the reliability of commonly used echocardiographic parameters, making the diagnosis challenging. Therefore, a multimodality imaging approach, including computed tomography or cardiac magnetic resonance, is often not just beneficial but crucial. It represents the future of diagnostics in this intricate field due to its unprecedented capacity to quantify and comprehend valvular pathology. The absence of definitive data and guidelines for the therapeutic management of AS in the context of multiple valve lesions makes this condition particularly challenging. As a result, an individualized, case-by-case approach is necessary, guided primarily by the recommendations for the predominant valve lesion. This review aims to summarize the pathophysiology of AS in the context of multiple and mixed valve disease, with a focus on the hemodynamic implications, diagnostic challenges, and therapeutic options.

Impact of Concomitant Mitral Regurgitation on the Hemodynamic Indicators of Aortic Stenosis

Background In patients with aortic stenosis (AS), the presence of mitral regurgitation (MR) can lead to underestimation of AS severity and worse clinical outcomes. The objective of this study was to characterize the magnitude of the effects of concomitant MR on hemodynamic indicators of AS severity using clinical data and a computational cardiovascular simulation. Methods and Results Echocardiographic data from 1427 patients with severe AS were used to inform a computational cardiovascular system model, and varying degrees of MR and AS were simulated. Hemodynamic data, including left ventricular and aortic pressure waveforms, were generated for all simulations. Simulated reduction in mean transaortic pressure gradient (MPG) associated with MR was then used to calculate the adjusted MPG in the clinical cohort. MR was present in 861 (60%) patients. Compared with patients without MR, patients with MR had a lower aortic-valve area (0.83±0.2 cm2 versus 0.75±0.2; P<0.001) and were more likely to have a low-gradient pattern (MPG <40 mm Hg) (45% versus 54%; P<0.001). Simulations showed that the presence of concomitant mild, moderate, and severe MR with AS was accompanied by a mean reduction in MPG of 10%, 29%, and 40%, respectively. For patients with MR, their calculated adjusted MPG was on average 24% higher than their MPG (52±22 versus 42±16 mm Hg). Of the 467 patients with low-gradient AS and MR, 240 (51%) would reclassify as high gradient based on their adjusted MPG. Conclusions Concomitant MR results in lower MPG and reduced forward flow compared with isolated AS. Careful quantitation of MR should be factored into the assessment of AS severity to mitigate for potential underestimation.

Concomitant mitral regurgitation in patients with low-gradient aortic stenosis: an analysis from the German Aortic Valve Registry

BACKGROUND

Patients with severe aortic stenosis (AS) frequently presented mitral regurgitation (MR), which may interfere with the standard echocardiographic measurements of mean pressure gradient (MPG), flow velocity, and aortic valve area (AVA).

AIMS

Herein we investigated the prevalence and severity of MR in patients with severe AS and its role on the accuracy of the standard echocardiographic parameters of AS quantification.

METHODS

Of all patients with severe AS undergoing transcatheter or surgical aortic valve replacement enrolled in the German Aortic Registry from 2011 to 2017, 119,641 were included in this study. The population was divided based on the values of left ventricular ejection fraction ([LVEF] > 50%, LVEF 31-50%, and LVEF ≤ 30%] and AVA (0.80 to ≤ 1.00 cm2, 0.60 to < 0.80 cm2, 0.40 to < 0.60 cm2, and 0.20 to < 0.40 cm2).

RESULTS

Overall, 77,890 (65%) patients with mild to-moderate and 4262 (4%) with severe MR were compared with 37,489 (31%) patients without MR. Patients with mild-to-moderate and severe MR presented significantly lower mPG (ΔmPG [95%CI] - 1.694 mmHg [- 2.123 to - 1.265], p < 0.0001 and - 6.954 mmHg [- 7.725 to - 6.183], p < 0.0001, respectively), that increased with LVEF impairment. Conversely, AVA did not differ (severe versus no MR: ΔAVA [95%CI]: - 0.007cm2 [- 0.023 to 0.009], p = 0.973). Increasing MR severity was associated with significant mPG reduction throughout all AVA strata, causing a low-gradient pattern, that manifested since the early stages of severe AS (LVEF > 50%: AVA 0.80 to 1.00 cm2; LVEF 31-50%: AVA 0.60 to 0.80 cm2).

CONCLUSIONS

In patients with severe AS, concomitant MR is common, contributes to the onset of a low-gradient AS pattern, and affects the diagnostic accuracy of flow-dependent AVA measurements. In this setting, a multimodality, AVA-centric approach should be implemented. In patients with severe aortic stenosis, concomitant mitral regurgitation contributes to the onset of a low-gradient pattern, warranting a multimodality, and AVA-centric diagnostic approach.

When Aortic Stenosis Is Not Alone: Epidemiology, Pathophysiology, Diagnosis and Management in Mixed and Combined Valvular Disease

Aortic stenosis (AS) may present frequently combined with other valvular diseases or mixed with aortic regurgitation, with peculiar physio-pathological and clinical implications. The hemodynamic interactions between AS in mixed or combined valve disease depend on the specific combination of valve lesions and may result in diagnostic pitfalls at echocardiography; other imaging modalities may be helpful. Indeed, diagnosis is challenging because several echocardiographic methods commonly used to assess stenosis or regurgitation have been validated only in patients with the single-valve disease. Moreover, in the developed world, patients with multiple valve diseases tend to be older and more fragile over time; also, when more than one valvular lesion needs to address the surgical risk rises together with the long-term risk of morbidity and mortality associated with multiple valve prostheses, and the likelihood and risk of reoperation. Therefore, when AS presents mixed or combined valve disease, the heart valve team must integrate various parameters into the diagnosis and management strategy, including suitability for single or multiple transcatheter valve procedures. This review aims to summarize the most critical pathophysiological mechanisms underlying AS when associated with mitral regurgitation, mitral stenosis, aortic regurgitation, and tricuspid regurgitation. We will focus on echocardiography, clinical implications, and the most important treatment strategies.

The Common Combination of Aortic Stenosis with Mitral Regurgitation: Diagnostic Insight and Therapeutic Implications in the Modern Era of Advanced Echocardiography and Percutaneous Intervention

The combination of aortic stenosis (AS) and mitral regurgitation (MR) is common in patients with degenerative valvular disease. It is characterized by having complex pathophysiology, leading to potential diagnostic pitfalls. Evidence is scarce in the literature to direct the diagnostic framework and treatment of patients with this particular combination of multiple valvular diseases. In this complex scenario, the appropriate use of advanced echocardiography and multimodality imaging methods plays a central role. Transcatheter mitral valve replacement or repair and transcatheter aortic valve replacement widen the surgical options for valve diseases. Therefore, there is an increasing need to reconsider the function, timing, and mode intervention for patients with a combination of AS with MR towards more personalized treatment.

Clinical impact of mitral regurgitation in aortic valve stenosis: Insight from effective regurgitant orifice area

PURPOSE

Mechanisms leading to heart failure (HF) symptoms in aortic valve stenosis (AS) are contentious. We examined the impact of secondary mitral regurgitation (MR) on the symptomatic status in patients with AS.

METHODS

Outpatients performing echocardiography with any degree of AS, without organic mitral valve disease, mitral valve intervention, or aortic insufficiency were enrolled. MR was quantitatively defined through mitral effective regurgitant orifice area (EROA) using the proximal isovelocity surface area method. Patients were divided into two groups (New York Heart Association [NYHA] class I-II vs. NYHA class III-IV).

RESULTS

Five hundred and eighty-four patients were enrolled (484 NYHA I-II, 100 NYHA III-IV). More symptomatic patients had smaller aortic valve area (AVA), lower left ventricular ejection fraction (LVEF) and stroke volume, higher E/E', and LV global afterload. MR was present in 178 (30%) patients and EROA was <.20 cm² in 158 (89%). NYHA III-IV patients showed higher prevalence of MR (78% vs 21%, P < 0.0001) and larger EROA (.13±.08 cm² vs .09±.07 cm² , P < 0.0001). An association between EROA and symptoms was present in the total cohort and in subgroups with preserved LVEF, AVA ≥ 1 and <1 cm² , EE' 8-14 and ≥14 (P < 0.05 for all). EROA was associated with severe symptoms after adjustment for LVEF, E/E', and AVA in the overall population (OR 1.10 [1.06-1.15]; P < 0.0001) and in the 516 patients with preserved LVEF (OR 1.13 [1.08-1.19]; P < 0.0001).

CONCLUSION

In patients with AS, greater EROA values are associated with HF symptoms, even though MR degree is far from the threshold of MR severity. Therefore, even a mild MR represents a supportive marker of HF symptoms presence.

Mitral Valvular Coaptation-Zone Area Is Associated with the Severity of Atherosclerosis Assessed by Cardio-Ankle Vascular Index

Preservation of the mitral valve (MV) size is essential for valve function, and a reduced MV coaptation-zone area increases the risk of developing functional mitral regurgitation (FMR). We aimed to determine if the MV leaflet and coaptation-zone areas were associated with the severity of atherosclerosis assessed by cardio-ankle vascular index (CAVI) in patients with normal left ventricle (LV) systolic function and size by real-time 3D echocardiography (RT3DE).We performed RT3DE analysis in 66 patients with normal LV size and ejection fraction who underwent 2D echocardiography and CAVI. MV coaptation-zone areas were measured by custom 3D software and indexed by body surface area (BSA). The associations of clinical factors and mean CAVI with MV leaflet and coaptation-zone areas were evaluated by univariable and multivariable linear regression analyses.On univariable analysis, MV leaflet area/BSA was significantly associated with age (r = -0.335, P = 0.0069) and mean CAVI (r = -0.464, P < 0.001), and MV coaptation-zone area was significantly associated with age (r = -0.626, P < 0.001), hypertension (r = -0.626, P < 0.001), dyslipidemia (r = -0.626, P < 0.001), E/e' (r = -0.626, P < 0.001), and CAVI (r = -0.740, P < 0.001). On multivariable analysis, mean CAVI was independently associated only with MV leaflet area/BSA (standardized coefficient = -0.611, P < 0.001) and MV coaptation-zone area/BSA (standardized coefficient = -0.74, P < 0.001).In patients with normal LV systolic function and size, MV leaflet and coaptation-zone areas might be reduced according to advancing atherosclerosis. Patients with atherosclerosis might be at increased risk of developing FMR.

Relationship Between Mitral Leaflet Size and Coaptation and Their Associated Factors in Patients with Normal Left Ventricular Size and Systolic Function

Enlargement of the mitral valve (MV) has gained attention as a compensatory mechanism for functional mitral regurgitation (FMR). We aimed to determine if MV leaflet area is associated with MV coaptation-zone area and identify the clinical factors associated with MV leaflet size and coaptation-zone area in patients with normal left ventricle (LV) systolic function and size using real-time 3D echocardiography (RT3DE).We performed RT3DE in 135 patients with normal LV size and ejection fraction. MV leaflet and coaptation-zone areas were measured using custom 3D software. The clinical factors associated with MV leaflet and coaptation-zone areas were evaluated using univariate and multivariate linear regression analyses.There was a significant relationship between MV leaflet and coaptation-zone areas (r = 0.499, P < 0.001). MV leaflet area was strongly associated with body surface area (BSA) (r = 0.905, P < 0.001) rather than LV size and age. MV leaflet area/BSA was independently associated with male gender (P = 0.002), lower diastolic blood pressure (P = 0.042), and LV end-diastolic volume (LVEDV) index (P = 0.048); MV coaptation-zone area/BSA was independently associated with lower LVEDV index (P = 0.01).In patients with normal LV systolic function and size, MV leaflet size has a significant impact on competent MV coaptation. MV leaflet area might be intrinsically determined by body size rather than age and LV size, and the MV leaflet area/BSA is relatively constant. On the other hand, some clinical factors might also influence MV leaflet and coaptation-zone area.

Relevance of Functional Mitral Regurgitation in Aortic Valve Stenosis

The clinical relevance of functional-mitral-regurgitation (FMR) in patients with aortic valve stenosis (AS) has been poorly studied using a quantitative approach. In addition, FMR prognostic value has mostly been analyzed after aortic valve replacement. Between 2010 and 2014 the echocardiograms of consecutive AS patients were retrospectively reviewed. Inclusion criteria were calcified aortic valve with transaortic-velocity >2.5 m/s and calculated mitral effective regurgitant orifice area (ERO) in the presence of mitral regurgitation. Organic mitral valve disease was an exclusion-criteria. Primary endpoint was heart failure or death under medical management. Secondary endpoint was heart failure or death. Eligible patients were 189, age 79 ± 8 years, 61% NYHA I/II, indexed aortic valve area (AVA) 0.55 ± 0.17 cm²/m². Mitral ERO was 7.6 ± 4.2 mm² (>10 mm² in 30% of patients). Longitudinal function (by S'-TDI) was associated with mitral ERO independently of ejection fraction and ventricular volumes (p = 0.01). Mitral ERO greater than 10 mm² (threshold identified by spline survival-modeling) was associated with severe symptoms (Odds ratio [OR] 3.1 [1.6 to 6.0]; p = 0.0006) and higher pulmonary-arterial-pressure (OR 3.0 [1.4 to 5.9]; p = 0.002). Follow-up was completed for 175 patients. After 4.7 [1.4 to 7.2] years, 87 (50%) patients underwent AVR, 66 (38%) had heart-failure, 64 (37%) died. No procedure on FMR was required. Mitral ERO was independently associated with primary and secondary endpoints both as continuous variable (Hazard ratio [HR] 1.15 [1.00 to 1.30]; p = 0.04 and HR 1.23 [1.05 to 1.43]; p = 0.01 per 5 mm² ERO increase) or as ERO> versus ≤10 mm². Adjustment for S'-TDI or subgroup-analysis did not affect results. The analysis by AVA revealed the incremental prognostic role of mitral ERO over AS severity. In conclusion, AS patients with concomitant FMR >10 mm² holds a higher risk during medical follow-up. FMR quantitation, even for volumetrically modest regurgitation, provides incremental prognostic information over AS severity.

Excess Mortality Associated with Progression Rate in Asymptomatic Aortic Valve Stenosis

BACKGROUND

Aortic valve stenosis (AS) is a progressive condition characterized by gradual calcification of the aortic cusps. Progression rate evaluated using echocardiography has been associated with survival. However, data from routine practice covering the whole spectrum of AS severity and the rate of symptom onset are sparse. The aim of this study was to assess outcomes under medical management related to disease progression in asymptomatic patients with a wide range of AS severity.

METHODS

Two hundred twenty-nine consecutive asymptomatic patients (mean age, 77 ± 10 years; 55% men) with AS, preserved left ventricular ejection fraction, and two or more echocardiographic examinations performed from 2004 to 2014 were retrospectively included. The median time between the two echocardiographic examinations was 24 months (interquartile range, 15-46 months). Patients were identified as rapid progressors if the annualized difference in peak aortic velocity between two echocardiographic examinations was ≥0.3 m/sec/y; others were labeled as slow progressors. The primary end point was mortality during medical follow-up (censoring on aortic valve interventions). The secondary end point was overall mortality.

RESULTS

Rapid progressors accounted for 67 of the 229 patients (29%), and this feature was not associated with baseline characteristics. During a median of 5.8 years (interquartile range, 3.4-8.3 years) of follow-up from the first echocardiographic examination, 102 patients (45%) died, 86 (84%) during medical follow-up. Rapid progression rate predicted excess mortality (vs slow progression rate) after adjustment for age, sex, symptoms, baseline left ventricular ejection fraction, and baseline aortic valve area (hazard ratio, 2.50; 95% CI, 1.48-4.21; P = .0006) and after adjusting for peak aortic velocity and left ventricular ejection fraction obtained at the last echocardiographic examination (hazard ratio, 2.07; 95% CI, 1.25-3.46; P = .005). Among patients with baseline peak aortic velocity < 4 m/sec (nonsevere AS), rapid progression rate was associated with higher 5-year mortality compared with slow progression (57% vs 22% [P < .0001] under medical management and 44% vs 18% [P = .005] overall). Outcomes were comparable between nonsevere AS rapid progressors and baseline severe AS. Progression rate showed incremental prognostic value on receiver operating characteristic curve analysis versus AS severity. Of note, among slow progressors, 11 patients (5%) presented with high rates of symptom development and poor outcomes related to ventricular dysfunction or other advanced AS features.

CONCLUSIONS

Progression rate is an individual, almost unpredictable feature among patients with AS. Rapid progression is an incremental marker of excess mortality in asymptomatic patients with AS, independent of clinical and hemodynamic characteristics. Rapid progression rate may identify patients with nonsevere AS at higher risk for events.

Impact of concomitant mitral regurgitation on transvalvular gradient and flow in severe aortic stenosis: a systematic ex vivo analysis of a subentity of low-flow low-gradient aortic stenosis

AIMS

Evaluation of aortic stenosis (AS) is based on echocardiographic measurement of mean pressure gradient (MPG), flow velocity (Vmax) and aortic valve area (AVA). The objective of the present study was to analyse the impact of systemic haemodynamic variables and concomitant mitral regurgitation (MR) on aortic MPG, Vmax and AVA in severe AS.

METHODS AND RESULTS

A pulsatile circulatory model was designed to study function and interdependence of stenotic aortic (AVA: 1.0 cm², 0.8 cm² and 0.6 cm²) and insufficient mitral prosthetic valves (n=8; effective regurgitant orifice area [EROA] <0.2 cm² vs. >0.4 cm²) using Doppler ultrasound. In the absence of severe MR, a stepwise increase of stroke volume (SV) and a decrease of AVA was associated with a proportional increase of aortic MPG. When MR with EROA <0.2 cm² vs. >0.4 cm² was introduced, forward SV decreased significantly (70.9±1.1 ml vs. 60.8±1.6 ml vs. 47.4±1.1 ml; p=0.02) while MR volume increased proportionally. This was associated with a subsequent reduction of aortic MPG (57.1±9.4 mmHg vs. 48.6±13.8 mmHg vs. 33.64±9.5 mmHg; p=0.035) and Vmax (5.09±0.4 m/s vs. 4.91±0.73 m/s vs. 3.75±0.57 m/s; p=0.007). Calculated AVA remained unchanged (without MR: AVA=0.53±0.04 cm² vs. with MR: AVA=0.52±0.05 cm²; p=ns). In the setting of severe AS without MR, changes of vascular resistance (SVR) and compliance (C) did not impact on aortic MPG (low SVR and C: 66±13.8 mmHg and 61.1±20 mmHg vs. high SVR and C: 60.9±9.2 mmHg and 71.5±13.5 mmHg; p=ns) In concomitant severe MR, aortic MPG and Vmax were not significantly reduced by increased SVR (36.6±2.2 mmHg vs. 34.9±5.6 mmHg, p=0.608; 3.89±0.18 m/s vs. 3.96±0.28 m/s; p=ns).

CONCLUSIONS

Systemic haemodynamic variables and concomitant MR may potentially affect diagnostic accuracy of echocardiographic AS evaluation. As demonstrated in the present study, MPG and Vmax are flow-dependent and significantly reduced by a reduction of forward SV from concomitant severe MR, resulting in another entity of low-flow low-gradient aortic stenosis. In contrast, calculated AVA appears to be a robust parameter of AS evaluation if severe MR is present. Changes of SVR and C did not affect the diagnostic accuracy of AS evaluation.

Mitral Regurgitation and Increased Risk of All-Cause and Cardiovascular Mortality in Patients with Type 2 Diabetes

BACKGROUND

Mitral regurgitation is the most common heart valve disease in the general population, but little is known about the prevalence and prognostic implications of mitral regurgitation in patients with type 2 diabetes.

METHODS

We retrospectively analyzed the data from 814 outpatients with type 2 diabetes who had undergone a conventional echocardiography for clinical reasons during the years 1992-2007. Mitral regurgitation was evaluated by using an integrated multiparametric echocardiographic approach. The study outcomes were all-cause and cardiovascular mortality.

RESULTS

At baseline, 261 (32%) patients had mitral regurgitation (25% mild, 5% moderate, and 2% severe). Over a mean follow-up of 9 years, 120 (14%) patients died, 50 of them from cardiovascular causes. Compared with those without valve disease, patients with mild mitral regurgitation had a 3.3-fold increased risk of all-cause mortality, whereas those with moderate-to-severe mitral regurgitation had a 5.1-fold increased risk of all-cause mortality. Results remained statistically significant after adjustment for multiple potential confounders. Similar results were found for cardiovascular mortality.

CONCLUSIONS

Mitral regurgitation is a common pathologic condition in patients with type 2 diabetes and is independently associated with an increased risk of both all-cause and cardiovascular mortality, even if the severity of mitral regurgitation is mild.

The year 2014 in the European Heart Journal--Cardiovascular Imaging: part II

The European Heart Journal-Cardiovascular Imaging, created in 2012, has become a reference for publishing multimodality cardiovascular imaging scientific and review papers. The impressive 2014 impact factor of 4.105 confirms the important position of our journal. In this part, we summarize the most important studies from the journal's third year, with specific emphasis on cardiomyopathies, congenital heart diseases, valvular heart diseases, and heart failure.

The left ventricle in aortic stenosis--imaging assessment and clinical implications

Aortic stenosis has an increasing prevalence in the context of aging population. In these patients non-invasive imaging allows not only the grading of valve stenosis severity, but also the assessment of left ventricular function. These two goals play a key role in clinical decision-making. Although left ventricular ejection fraction is currently the only left ventricular function parameter that guides intervention, current imaging techniques are able to detect early changes in LV structure and function even in asymptomatic patients with significant aortic stenosis and preserved ejection fraction. Moreover, new imaging parameters emerged as predictors of disease progression in patients with aortic stenosis. Although proper standardization and confirmatory data from large prospective studies are needed, these novel parameters have the potential of becoming useful tools in guiding intervention in asymptomatic patients with aortic stenosis and stratify risk in symptomatic patients undergoing aortic valve replacement.

This review focuses on the mechanisms of transition from compensatory left ventricular hypertrophy to left ventricular dysfunction and heart failure in aortic stenosis and the role of non-invasive imaging assessment of the left ventricular geometry and function in these patients.