The natural history of asymptomatic patients with aortic regurgitation and normal left ventricular function

Noninvasive Imaging for Native Aortic Valve Regurgitation

Aortic regurgitation (AR) is associated with left ventricular (LV) volume and pressure overload, resulting in eccentric LV remodeling and enlargement. This condition may be well tolerated for years before the onset of myocardial dysfunction and symptoms. Echocardiography plays a crucial role in the diagnosis of AR, assessing its mechanism and severity, and detecting LV remodeling. The assessment of AR severity is challenging and frequently requires the integration of information from multiple different measurements to assess the severity. Recent data suggest that echocardiographically derived LV volumes (end-systolic volume index > 45 mL/m2), an ejection fraction threshold of <60%, and abnormal global longitudinal strain may help identify early dysfunction and may be used to improve clinical outcomes. Consequently, these parameters can identify candidates for surgery. Cardiac magnetic resonance imaging is emerging as a valuable tool for assessing severity when it remains unclear after an echocardiographic evaluation. This review emphasizes the importance of imaging, particularly echocardiography, in the evaluation of AR. It focuses on various echocardiographic parameters, including technical details, and how to integrate them for assessing the mechanism and severity of AR as well as LV remodeling.

Echocardiographic Markers of Early Left Ventricular Dysfunction in Asymptomatic Aortic Regurgitation: Is It Time to Change the Guidelines?

BACKGROUND

The ideal timing for surgery in asymptomatic chronic aortic regurgitation (AR) remains unclear. New thresholds for left ventricular ejection fraction (LVEF), left ventricular (LV) indexed end-systolic volume (iESV), and global longitudinal strain (GLS) have been associated with mortality in these patients. These represent markers of early LV dysfunction.

OBJECTIVES

The authors sought to assess the relationship between these markers (LVEF <60%, iESV ≥45 mL/m2, and GLS worse than -15%) and mortality, comparing them to Class I/IIa American College of Cardiology/American Heart Association guideline recommendations and absence of any of these.

METHODS

A total of 673 asymptomatic patients with chronic clinically significant (≥ moderate-severe) AR between 2004 and 2019 at a single referral center were retrospectively analyzed. The primary study outcome was all-cause mortality.

RESULTS

Mean age was 57 ± 17 years, 97 (14%) were female, 293 (45%) had hypertension, and 273 (41%) had an abnormal number of valve cusps. Aortic valve replacement was performed in 281 (48%) patients, and 69 (10%) died while under surveillance (without aortic valve replacement). LVEF <60% was present in 296 (44%) patients, 122 (25%) of 482 had GLS worse than -15%, and 261 (39%) had iESV ≥45 mL/m2. Mortality under surveillance was highest when Class I/IIa recommendations were present (HR: 4.22; 95% CI: 2.15-8.29), followed by the presence of 1 or more markers of early LV dysfunction (HR: 2.18; 95% CI: 1.21-3.92); no markers was used as the reference (all, P < 0.05). LVEF showed the strongest association with mortality, statistically slightly better than GLS and iESV. In the absence of Class I/IIa recommendations, 1 marker of early LV dysfunction was associated with higher, although not statistically significant, mortality compared with no markers (P = 0.063), followed by 2 markers; highest mortality was when all 3 markers were present (HR: 5.46; 95% CI: 2.51-11.90; P < 0.001).

CONCLUSIONS

Patients with asymptomatic clinically significant chronic AR incur a survival penalty when Class I/IIa guideline recommendations are attained. In patients without these recommendations, at least 2 markers of early LV dysfunction identify those with higher mortality risk who may benefit from early surgery.

Magnetic resonance analysis of ventricular volumes in bicuspid and trileaflet aortic regurgitation

OBJECTIVE

To identify differences in left ventricular (LV) remodelling between patients with bicuspid aortic valve (BAV) and trileaflet aortic valve (TAV) with chronic aortic regurgitation (AR).

METHODS

Retrospective cohort study of 210 consecutive patients undergoing cardiac magnetic resonance for AR evaluation. We divided the study population according to valvular morphology. Independent predictors of LV enlargement AR were evaluated.

RESULTS

There were 110 patients with BAV and 100 patients with TAV. Patients with BAV were younger (mean age BAV vs TAV: 41±16 years vs 67±11 years; p<0.01), mostly male (% male BAV vs TAV: 84.5% vs 65%, p=0.01) and presented milder degrees of AR (median regurgitant fraction BAV vs TAV: 14 (6-28)% vs 22 (12-35)%, p=0.002). Both groups presented similar indexed LV volumes and ejection fraction. According to the degree of AR, at mild AR, patients with BAV presented larger LV volumes (BAV vs TAV: indexed end diastolic left ventricular volumes (iEDV): 96.5±19.7 vs 82.1±19.3 mL, p<0.01; indexed end systolic left ventricular volumes (iESV): 39.4±10.3 mL vs 33.2±10.5 mL, p=0.01). These differences disappeared at higher degrees of AR. Independent predictors of LV enlargement were regurgitant fraction (EDV: OR 1.118 (1.081-1.156), p<0.001; ESV: OR 1.067 (1.042-1.092), p<0.001), age (EDV: OR 0.940 (0.917-0.964), p<0.001, ESV: OR 0.962 (0.945-0.979), p<0.001) and weight (EDV: OR 1.054 (1.025-1.083), p<0.001).

CONCLUSIONS

In chronic AR, LV enlargement is an early finding. LV volumes display a direct correlation with regurgitant fraction and an inverse association with age. Patients with BAV present larger ventricular volumes, especially at mild AR. However, these differences are attributable to demographic disparities; valve type is not independently associated with LV size.

Aortic Regurgitation and Heart Failure: Advances in Diagnosis, Management, and Interventions

This review discusses the contemporary clinical evaluation and management of patients with comorbid aortic regurgitation (AR) and heart failure (HF) (AR-HF). Importantly, as clinical HF exists along the spectrum of AR severity, the present review also details novel strategies to detect early signs of HF before the clinical syndrome ensues. Indeed, there may be a vulnerable cohort of AR patients who benefit from early detection and management of HF. Additionally, while the mainstay of operative management for AR has historically been surgical aortic valve replacement, this review discusses alternate procedures that may be beneficial in high-risk cohorts.

Machine learning-based risk stratification for mortality in patients with severe aortic regurgitation

Aims

The current guidelines recommend aortic valve intervention in patients with severe aortic regurgitation (AR) with the onset of symptoms, left ventricular enlargement, or systolic dysfunction. Recent studies have suggested that we might be missing the window of early intervention in a significant number of patients by following the guidelines.

Methods and results

The overarching goal was to determine if machine learning (ML)-based algorithms could be trained to identify patients at risk for death from AR independent of aortic valve replacement (AVR). Models were trained with five-fold cross-validation on a dataset of 1035 patients, and performance was reported on an independent dataset of 207 patients. Optimal predictive performance was observed with a conditional random survival forest model. A subset of 19/41 variables was selected for inclusion in the final model. Variable selection was performed with 10-fold cross-validation using random survival forest model. The top variables included were age, body surface area, body mass index, diastolic blood pressure, New York Heart Association class, AVR, comorbidities, ejection fraction, end-diastolic volume, and end-systolic dimension, and the relative variable importance averaged across five splits of cross-validation in each repeat were evaluated. The concordance index for predicting survival of the best-performing model was 0.84 at 1 year, 0.86 at 2 years, and 0.87 overall, respectively.

Conclusion

Using common echocardiographic parameters and patient characteristics, we successfully trained multiple ML models to predict survival in patients with severe AR. This technique could be applied to identify high-risk patients who would benefit from early intervention, thereby improving patient outcomes.

Predictors of heart failure and all-cause mortality in asymptomatic patients with moderate and severe aortic regurgitation

BACKGROUND

Class I indications for aortic valve replacement (AVR) for severe chronic aortic regurgitation (AR) include AR attributable symptoms or left ventricular (LV) ejection fraction <50%. As noninvasive estimates of elevated LV filling pressures (LVFP's) have been noted to predict heart failure (HF) readmission and all-cause mortality (ACM) in HF patients, we hypothesize that elevated LVFP's may also be independent predictors of HF and ACM in chronic AR.

METHODS

We developed a single center patient database of moderate or greater AR diagnoses between 2003 and 2008 and followed each patient through January 2013. We included patients with >30 days follow-up with interpretable Doppler-echocardiograms. We recorded demographic variables, EuroScore II, incident HF and ACM, and Doppler-echo variables of LV size, systolic and diastolic function.

RESULTS

Patients with severe AR (105 patients) and moderate AR (201 patients) had similar EuroScore II values and similar incident HF and ACM. For the 180 patients who developed HF, effective arterial elastance (aHR = 1.70 (1.01-2.83), p = .041), LV end-diastolic dimension (aHR = 1.83, (1.11-3.03), p = .0176), E/e' (aHR = 3.04, (1.83-5.05), p < .0001), eccentric hypertrophy (EH) (aHR = 2.39, (1.62-5.12), p = .0004), and tricuspid regurgitation (TR) velocity (aHR = 5.75, (3.70-10.36), p < .0001) were independent predictors. For the 118 patients with ACM, EH (aHR = 1.73, (1.02-3.28), p = .0414), systolic blood pressure (aHR = .58, (.33-.95), p = .0301), left atrial volume index (aHR = 1.82, (1.06-3.06), p = .0293), E/e' (aHR = 1.83, (1.07-3.08), p = .0280), and TR velocity (aHR = 4.14, (2.22-6.49), p < .0001) were independent predictors.

CONCLUSIONS

Elevated TR velocity and EH were strong markers of HF and ACM in patients with asymptomatic severe AR and in moderate AR.

Differences in Cardiac Remodeling in Left-Sided Valvular Regurgitation: Implications for Optimal Definition of Significant Aortic Regurgitation

BACKGROUND

Grading of aortic regurgitation (AR) and mitral regurgitation (MR) is similar in the cardiology guidelines despite distinct differences in left ventricular (LV) adaptive pathophysiology.

OBJECTIVES

This study compared differences in LV remodeling in patients with similar degrees of AR and MR severity and evaluated optimal cutoffs for significant AR in relation to the outcome of aortic valve replacement or repair (AVR) during follow-up.

METHODS

From 2008 to 2018, consecutive patients with isolated AR or MR who had cardiovascular magnetic resonance (CMR) were identified and CMR parameters were compared. Patients with left ventricular ejection fraction (LVEF) <50%, ischemic scar >5%, valve stenosis, or concomitant regurgitation were excluded. Patients were followed longitudinally for AVR.

RESULTS

Baseline characteristics of isolated AR (n = 418) and isolated MR (n = 1,073) were comparable except for higher male proportion and hypertension in AR, while heart failure was more prevalent in MR. Indexed LV end-diastolic and end-systolic volumes and mass were higher in AR compared with MR at the same level of regurgitant fraction. During follow-up (mean 2.1 years), 18.7% of AR patients underwent AVR based on symptoms or LV remodeling. Interestingly, 38.0% of patients that underwent AVR within 3 months after CMR did not meet severe AVR by current guidelines of AR severity. AR regurgitant fraction>35% had high sensitivity (86%) and specificity (88%) for identifying patients who underwent AVR.

CONCLUSIONS

For similar regurgitation severity, LV remodeling is different in AR compared with MR. Cardiac symptoms and significant LV remodeling in AR requiring AVR occur frequently in patients with less severity than currently proposed. The study findings suggest that the optimal threshold for severe AR with CMR is different than MR and is lower than currently stated in the guidelines.

Epidemiology of Valvular Heart Disease

Acquired diseases of the aortic and mitral valves are the most common cause of morbidity and mortality among Valvular heart diseases. Aortic stenosis (AS) is increasing in incidence in the United States (4,43 US), driven largely by an aging demographic. Aortic valve replacement is the only effective treatment of AS and has a dramatic mortality benefit. Mitral valve regurgitation (MR) is the most common form of valvular heart disease (VHD) in the US, whereby MR is most often the result of mitral valve prolapse; rheumatic heart disease (RHD) is a more common etiology of MR in underdeveloped countries. interventions for MR in the US are increasing.

l -Arginine Can Enhance the Beneficial Effect of Losartan in Patients with Chronic Aortic Regurgitation and Isolated Systolic Hypertension

Information about the effects of angiotensin II receptor blocker (ARB) therapy on the hemodynamic and cardiac structure in patients with chronic aortic regurgitation (CAR) and isolated systolic hypertension (ISH) is limited. This study planned to test the hypothesis that l -arginine could further enhance the beneficial effect of an ARB, losartan, and provide a favorable effect on the natural history of CAR and ISH. Sixty patients with CAR and ISH were enrolled in a randomized, double-blind trial comparing hemodynamic and ultrasonic change in two treatment arms: losartan +  l -arginine and losartan-only treated groups. Serial echocardiographic and hemodynamic studies were evaluated before and after treatment. Both groups had a significant reduction in systolic blood pressure (SBP) and diastolic blood pressure (DBP), left ventricular end-diastolic volume index (LVEDVI), LV end-systolic volume index (LVESVI), LV mass index (LVMI), and LV mean wall stress after 6- and 12-month treatment ( p <0.01 in all comparisons). Both groups had a significant increase in LV ejection fraction and exercise duration after 6- and 12-month treatment ( p  < 0.01 in all comparisons). Using multivariate linear regression analysis, only losartan +  l -arginine therapy achieved a significantly lower LVESVI (38.89 ± 0.23 mL/m ² ), LVEDVI (102.3 ± 0.3 mL/m ² ), LVMI (107.6 ± 0.3 g/m ² ), SBP (123.5 ± 1.0 mm Hg), and greater exercise duration (7.38 ± 0.02 minutes) than those of the losartan-only treated groups ( p <0.01 in all comparisons). These findings suggest that early co-administrative strategy provides a beneficial approach to favorably influence the natural history of CAR.

The International Society for Minimally Invasive Cardiothoracic Surgery Expert Consensus Statement on Transcatheter and Surgical Aortic Valve Replacement in Low- and Intermediate-Risk Patients: A Meta-Analysis of Randomized and Propensity-Matched Studies

OBJECTIVE

There is an increasing amount of evidence supporting use of transcatheter aortic valve replacement (TAVR) for treatment of aortic stenosis in patients at low or intermediate risk for surgical aortic valve replacement (SAVR). TAVR is now approved for use in all patient cohorts. Despite this, there remains debate about the relative efficacy of TAVR compared with SAVR in lower-risk cohorts and various subgroups of patients. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) and propensity-matched trials to guide a consensus among expert cardiologists and surgeons.

METHODS

Studies comparing TAVR and SAVR in low- and intermediate-risk patients were identified by a thorough search of the major databases. Mortality, stroke, and other perioperative outcomes were assessed at 30 days and 1 year.

RESULTS

Early mortality was lower in TAVR compared to SAVR in RCTs, but not propensity-matched studies in low-risk cohorts (0.66% vs 1.5%; odds ratio [OR] = 0.44, 95% confidence interval [CI] 0.20 to 0.98, I² = 0%). No difference in mortality between TAVR and SAVR was identified in intermediate-risk patients at early or later time points. Incidence of perioperative stroke in 3 low-risk RCTs was significantly lower in TAVR (0.4%) than SAVR (1.4%; OR = 0.33, 95% CI 0.13 to 0.81, I² = 0%). There was no difference in stroke for intermediate-risk patients between TAVR and SAVR. The expert panel of cardiologists and cardiac surgeons provided recommendations for TAVR and SAVR in various clinical scenarios.

CONCLUSIONS

In RCTs comparing TAVR and SAVR in low-risk patients, early mortality and stroke were lower in TAVR, but did not differ at 1 year. There was no difference in mortality and stroke in intermediate-risk patients. The Multidisciplinary Heart Team must consider individual patient characteristics and preferences when recommending TAVR or SAVR. The decision must consider the long-term management of each patient's aortic valve disease.

Disparate impact of severe aortic and mitral regurgitation on left ventricular dilation

In asymptomatic severe aortic (AR) and mitral regurgitation (MR), left ventricular (LV) dimension criteria were established to guide timing of valve replacement to prevent irreversible LV dysfunction. Given both lesions are primary LV volume overload ''leaks'', it might be expected that both lesions would induce similar impact on the LV and result in equivalent dimension criteria for intervention. However, the dimension-based intervention criteria for AR versus MR (developed through natural history studies), differ markedly. The pathophysiological foundations for such discordance have neither been fully elucidated nor emphasized. This case-based treatise compares the two regurgitant lesions with respect to: (a) ''total regurgitant circuits''; (b) ''driving pressures'' resulting in LV volume overload from each respective ''leak''; and (c) volume and afterload wall stresses imposed on the LV.Key points The ''total circuits'' of volume overload differ: The AR circuit includes the LV and systemic vasculature, whereas MR includes the LV ejecting into the left atrium/pulmonary veins and systemic circulation. The ''driving pressure'' of regurgitation and afterload are high with AR and low with MR. Differing ''total circuits'' and ''driving pressures'' impose disparate wall stresses upon the LV. Parallel and serial sarcomere replication occurs in AR, while only serial replication occurs in MR. It therefore follows that for regurgitation of similar severities, AR results in greater LV dilation at the point of irreversible myocardial dysfunction compared to MR. These considerations may explain, at least in part, the disparate dimension criteria employed for valve intervention for severe AR vs MR.

Aortic regurgitation assessment by cardiovascular magnetic resonance imaging and transthoracic echocardiography: intermodality disagreement impacting on prediction of post-surgical left ventricular remodeling

Transthoracic echocardiography (TTE) is the primary clinical imaging modality for the assessment of patients with isolated aortic regurgitation (AR) in whom TTE's linear left ventricular (LV) dimension is used to assess disease severity to guide aortic valve replacement (AVR), yet TTE is relatively limited with regards to its integrated semi-quantitative/qualitative approach. We therefore compared TTE and cardiovascular magnetic resonance (CMR) assessment of isolated AR and investigated each modality's ability to predict LV remodeling after AVR. AR severity grading by CMR and TTE were compared in 101 consecutive patients referred for CMR assessment of chronic AR. LV end-diastolic diameter and end-systolic diameter measurements by both modalities were compared. Twenty-four patients subsequently had isolated AVR. The pre-AVR estimates of regurgitation severity by CMR and TTE were correlated with favorable post-AVR LV remodeling. AR severity grade agreement between CMR and TTE was moderate (ρ = 0.317, P = 0.001). TTE underestimated CMR LV end-diastolic and LV end-systolic diameter by 6.6 mm (P < 0.001, CI 5.8-7.7) and 5.9 mm (P < 0.001, CI 4.1-7.6), respectively. The correlation of post-AVR LV remodeling with CMR AR grade (ρ = 0.578, P = 0.004) and AR volumes (R = 0.664, P < 0.001) was stronger in comparison to TTE (ρ = 0.511, P = 0.011; R = 0.318, P = 0.2). In chronic AR, CMR provides more prognostic relevant information than TTE in assessing AR severity. CMR should be considered in the management of chronic AR patients being considered for AVR.

Diagnostic value of noninvasive pulse pressure measurements in Warmblood horses with aortic regurgitation

Background

Noninvasive blood pressures (NIBP) and pulse pressures (PP) have not been published in horses with aortic and mitral regurgitation (AR or MR).

Objectives

To investigate NIBP and PP in healthy Warmblood horses and horses with AR and MR and propose PP cutoffs to identify and stage AR severity.

Animals

Seventy‐three Warmblood horses (healthy, 10; AR, 31; MR, 32).

Methods

Retrospective study. All horses had NIBP and an echocardiogram recorded. Cases were categorized based on severity of regurgitation. Pulse pressures were compared among healthy, MR, and AR groups and among AR severity groups. Cutoffs were determined by receiver operating characteristic curve analyses.

Results

Horses with AR had higher PP than horses with MR (mean difference [95% confidence interval (CI)], +17 [9‐26] mm Hg, P < .001) and controls (+17 [5‐30] mm Hg; P =.004). Horses with severe AR had higher PP compared those with mild (+38 [20‐54] mm Hg; P < 0.001) and moderate AR (+33 [18‐47] mm Hg; P < .001). The PP cutoffs to distinguish AR from MR and controls were 38 mm Hg (sensitivity [Sn], 100%; specificity [Sp], 19%) for maximal Sn and 61 mm Hg (Sn, 43%; Sp, 100%) for maximal Sp. The PP cutoffs to distinguish severe AR from mild and moderate AR were 57 mm Hg (Sn, 100%; Sp, 70%) for maximal Sn and 77 mm Hg (Sn, 75%; Sp, 100%) for maximal Sp.

Conclusions and Clinical Importance

Horses with AR have increased PP. Noninvasive PP measurements interpreted with provided cutoffs may aid clinicians in diagnosing and staging severity of AR in horses.

Survival after Aortic Valve Replacement for Aortic Regurgitation: Prediction from Preoperative Contractility Measurement

BACKGROUND

Noninvasive measurement of myocardial contractility (end-systolic wall stress-adjusted change in left ventricular ejection fraction from rest to exercise [ΔLVEF - ΔESS]) predicts heart failure, subnormal LVEFrest, and sudden death in asymptomatic patients with chronic severe aortic regurgitation (AR). Here we assess the relation of preoperative ΔLVEF - ΔESS to survival after aortic valve replacement (AVR).

METHODS

Patients who underwent AVR for chronic, isolated, pure severe AR (n = 66) were followed for 13.0 ± 6.4 event-free years. Preoperative ΔLVEF - ΔESS (from combined echocardiographic and radionuclide cineangiographic data) enabled cohort stratification into 3 terciles (-1 to -11% [normal or mild] contractility deficit, -12 to -16% [moderate], and ≤-17% [severe], identical with segregation in our earlier study) to relate preoperative contractility to postoperative survival and to age- and gender-matched US census data.

RESULTS

Since AVR, 22 patients died (average annual risk [AAR] for all-cause mortality for the entire co hort = 3.15%). Preoperative ΔLVEF - ΔESS predicted postoperative survival (p = 0.009, log rank test). By contractility terciles, all-cause AARs were 1.44, 2.58, and 6.40%. Survival was lower than among US census comparators (p < 0.02), but the "mild" tercile was indistinguishable from census data (p = ns). By multivariable Cox regression, survival prediction by pre-AVR ΔLVEF - ΔESS was independent of, and superior to, prediction by age at surgery, gender, preoperative functional class, LVEFrest, LVEFexercise, change in LVEFrest to exercise, and LV diastolic or systolic dimensions (p ≤ 0.01, pre-AVR ΔLVEF - ΔESS vs. other covariates).

CONCLUSION

In severe AR, preoperative contractility predicts post-AVR survival and may be prognostically superior to clinical, geometric and performance descriptors, potentially impacting on patient selection for surgery.

Outcomes of surgical aortic valve replacement for mixed aortic valve disease

Background

Mixed aortic valve disease (MAVD) is associated with a poorer natural history compared with isolated lesions. However, clinical and echocardiographic outcomes for aortic valve replacement (AVR) in mixed disease are less well understood.

Methods

Retrospective review of AVRs (n=1,011) from 2000-2016. Isolated AVR, AVR + coronary bypass, and AVR + limited ascending aortic replacement were included. Predominant aortic stenosis (AS) group was stratified into group 1 (n=660) with concomitant mild or less aortic insufficiency (AI), and group 2 (n=197) with accompanying moderate or greater AI. Predominant AI group was stratified using the same schema for concomitant AS into groups 3 (n=143) and 4 (n=53). Median follow-up was 3.1 and 4.4 years respectively for AS and AI groups.

Results

For the predominant AS group (n=857) preoperatively, group 2 had a larger preoperative left ventricular end diastolic diameter (LVESD) (51.0±8.4 vs. 48.6±7.2, P=0.02) and lower preoperative left ventricular ejection fraction (LVEF) (57.6% vs. 60.2%, P=0.043). No differences in left ventricular (LV) dimensions, LV or right ventricular (RV) function was evident at follow up (P>0.05). After propensity matching for age, operation, and comorbidities, there was no difference in survival (P=0.19). After propensity matching for the predominant AI group (n=196), survival was lower for group 4 compared to 3 (P=0.02). There were no differences in LV dimensions, LV or RV function preoperatively or on follow-up (P>0.05).

Conclusions

Predominant AS associated with higher AI grades had larger LV dimensions and worse LV function preoperatively. These differences resolve after AVR with equivalent survival. However, predominant AI with more severe AS had reduced survival despite AVR.

Drug Therapy for Heart Valve Diseases

Valvular heart diseases (VHDs) are progressive. When not caused by acute comorbidities they are generally characterized by long asymptomatic phases during which hemodynamic severity may progress leading to morbidity and mortality. Treatment depends on VHD type and severity but when severe and symptomatic, usually involves mechanical intervention. Asymptomatic patients, and those who lack objective descriptors associated with high risk, are closely observed clinically with optimization of associated cardiovascular risk factors until surgical indications develop. Though often prescribed based on theory, no rigorous evidence supports pharmacological therapy in most chronic situations though drugs may be appropriate in acute valvular diseases, or as a bridge to surgery in severely decompensated patients. Herein, we examine evidence supporting drug use for chronic VHDs.

Timing of aortic valve intervention in pediatric chronic aortic insufficiency

The timing of aortic valve intervention (AVI) in pediatric patients with chronic aortic insufficiency (AI) is largely based on adult experience, which is fraught with uncertainty and controversy. Current adult guidelines in the absence of symptoms use left ventricular (LV) systolic function and LV dimensions to guide AVI timing, with few studies translating these recommendations to pediatric patients. This article reviews the current guidelines for AVI timing in chronic AI along with the emerging data for pediatric patients.

Benfluorex and Mortality: A Fresh Perspective

Benfluorex, a drug related to fenfluramine, has been sold under the trade name “Mediator” by Servier Laboratories and was introduced to the French market in 1976, licenced for the treatment of type 2 diabetes and dyslipidemia. Although the evidence that benfluorex increases the risk of mild valvular regurgitant abnormalities is convincing, it is also apparent that no data exist from which to calculate the risk of death attributable to benfluorex use. Despite this, two studies have attempted to make such estimates, the results of which have been the focus of much media attention. In this review, we attempt to provide a further assessment of the evidence base, explore the limitations of the estimates of death that have been made, and calculate the population risk of mild valvular regurgitation and hospitalisation attributable to benfluorex use. We conclude that the previously published estimates of deaths attributed to the use of this agent are unsafe, based on unfounded assumptions, and are highly likely to be inaccurate.

Mitral valve enlargement in chronic aortic regurgitation as a compensatory mechanism to prevent functional mitral regurgitation in the dilated left ventricle

OBJECTIVES

The aim of this study was to test the hypothesis that mitral valve (MV) enlargement occurring in chronic aortic regurgitation (AR) prevents functional mitral regurgitation (FMR).

BACKGROUND

Chronic AR causes left ventricular (LV) dilation, creating the potential for FMR. However, FMR is typically absent during compensated AR despite substantial LV enlargement. Increased mitral leaflet area has been identified in AR, but it is unknown whether increased MV size can represent a compensatory mechanism capable of preventing FMR.

METHODS

Database review of 816 patients with at least moderate AR evaluated the prevalence of FMR. A total of 90 patients were enrolled prospectively for 3-dimensional echocardiography (30 AR, 30 FMR, and 30 controls) to assess MV geometry including total leaflet area.

RESULTS

FMR was present in 5.6% of AR patients by database review. Prospectively, only 1 AR patient had more than mild FMR despite increased LV end-diastolic volume (82 ± 22, 86 ± 23, and 51 ± 12 cm(3)/m(2), respectively, for AR, FMR vs. control patients; p < 0.01) and similar sphericity index, annular area, and tethering distances compared with FMR. Total MV area was largest in AR (31.3% greater than normal), increasing significantly more than in FMR. The ratio of valve size to closure area was maintained in AR, whereas decreases in this ratio and LV ejection fraction independently predicted FMR.

CONCLUSIONS

FMR prevalence is low in chronic AR. MV leaflet area is significantly increased compared with control and FMR patients, preserving a normal relationship to the area needed for closure in the dilated LV. Understanding the mechanisms underlying this adaptation could lead to new therapeutic interventions to prevent FMR.

Aortic valve and ascending aorta guidelines for management and quality measures: executive summary

The Society of Thoracic Surgeons Clinical Practice Guidelines are intended to assist physicians and other health care providers in clinical decision making by describing a range of generally acceptable approaches for the diagnosis, management, or prevention of specific diseases or conditions. These guidelines should not be considered inclusive of all proper methods of care or exclusive of other methods of care reasonably directed at obtaining the same results. Moreover, these guidelines are subject to change over time, without notice. The ultimate judgment regarding the care of a particular patient must be made by the physician in light of the individual circumstances presented by the patient.

CME: long-term outcome in asymptomatic patients with severe aortic regurgitation, normal left ventricular ejection fraction, and severe left ventricular dilatation

BACKGROUND

Although the guidelines consider severe left ventricular (LV) dilatation a class IIaC indication for surgery in asymptomatic patients with severe aortic regurgitation (AR) and normal LV function, the optimal management remains controversial. We aimed to assess the LV enlargement, hypertrophy and function, and the outcomes in these patients by the presence of severe LV dilatation at baseline.

METHODS

From our 20-year database, we identified all asymptomatic patients with severe AR and LV ejection fraction (EF) >50% and ≥2 echocardiograms ≥1 year apart. LV end-diastolic diameter >70 mm or LV end-systolic diameter >50 mm or LV end-systolic diameter index >25 mm/m(2) defined severe LV dilatation. A composite end point included onset of symptoms or LV dysfunction.

RESULTS

Eighty-four patients (52 ± 18 years, 61 men) were enrolled and followed-up for 7.1 ± 5.1 years. Two groups were defined: 22 patients with and 62 patients without severe LV dilatation at baseline. The progression of LV dilatation and hypertrophy, and the LVEF at last exam were similar in both groups. Twelve of 22 and 34 of 62 patients (P = 0.59) reached the end point. Vasodilators did not modify the progression of LV enlargement/hypertrophy. Ten of 22 and 25 of 62 patients (P = 0.45) underwent surgery and had similar postoperative LV diameters, mass, EF.

CONCLUSIONS

The progression of LV enlargement/hypertrophy and outcomes in asymptomatic patients with severe AR, normal LV function, and severe LV dilatation or the postoperative LV parameters were not influenced by the severe LV dilatation, suggesting that a close follow-up could delay surgery in this population.

Pulmonary hypertension and long-term mortality in aortic and mitral regurgitation

BACKGROUND

Outcomes data in patients with aortic regurgitation or mitral regurgitation have been limited to small series with generally <10 years of follow-up. The quantitative impact of pulmonary artery hypertension has not been well described. The purpose of this study was to describe the 15-year mortality of aortic regurgitation and mitral regurgitation.

METHODS

Our institution's electronic echocardiography database was queried to identify those patients examined in 1992 and reported to have at least mild aortic regurgitation or mitral regurgitation. Patients were classified by semi-quantitative degree of regurgitation. Pulmonary artery systolic pressure was categorized as normal, borderline, mild, or moderate or greater hypertension (pulmonary artery systolic pressure >40 mm Hg). Age-stratified Cox proportional hazards models compared survival among groups and adjusted for sex, depressed left ventricular ejection fraction, and pulmonary artery systolic pressure. Mortality data were obtained from the 2008 Social Security Death Index.

RESULTS

Of 4984 echocardiograms performed in 4050 patients, 1156 patients (28%; aged 72±14 years) had at least mild aortic regurgitation and 1971 patients (49%; aged 69±16 years) had at least mild mitral regurgitation. Overall 15-year mortality in patients with aortic regurgitation was 74% and similar for all grades of aortic regurgitation. Overall 15-year mortality in patients with mitral regurgitation was 71% and got progressively worse with increasing severity grade of mitral regurgitation (63% for mild to 81% for at least moderate-to-severe). For both aortic and mitral regurgitation, moderate or greater pulmonary artery systolic hypertension was associated with increased mortality (in patients with aortic regurgitation, hazard ratio [HR], 1.94; 95% confidence interval [CI], 1.58-2.41, and in mitral regurgitation patients, HR, 1.48; 95% CI, 1.26-1.75).

CONCLUSION

Long-term (15-year) survival of patients with aortic regurgitation is poor and is independent of regurgitation severity. In contrast, long-term survival of patients with mitral regurgitation correlates with regurgitation severity. For both groups, moderate or greater pulmonary artery systolic hypertension identified those at highest risk.

Cutting precision in a novel aortic valve resection tool. Research in progress

BACKGROUND

We recently demonstrated the first in-vitro cutting results of a minimal-invasive aortic valve resection tool. The current study was designed to assess the cutting accuracy of this new device improved by the implementation of a linear motor-based propulsion unit.

METHODS

Native aortic valves of isolated swine hearts (valve diameter 17.8+/-0.9 mm, mean+/-S.D.) were artificially stenosed and calcified (n=7). Subsequently, valves were resected by the use of a new aortic valve resection tool. The cutting process was performed by fitting the instrument with foldable Nitinol cutting blades (diameter 15 mm) and two software-operated linear motors combined with separated manual rotation. Aortic valve area was measured pre- and postprocedure by software-guided binary area calculation. Aortic valve residue has been determined and the grade of accuracy has been assessed via calculating the average midpoint of the neoannulus. Furthermore, radial deviation of concentricity was calculated and cutting time was measured.

RESULTS

Aortic valve resection was successful in all cases and nearly all leaflets (2.5+/-0.4) with a weight of 0.22+/-0.12 g were cut. Aortic valve area increased significantly (0.3+/-0.1 cm(2) vs. 1.1+/-0.2 cm(2), P<0.001) with a mean cutting time of 49.7+/-15.0 s. Mean lateral leaflet rim within the annulus was 3.2+/-3.2 mm. Cutting precision revealed a median deviation of the cutting ring from the desired position of 1.3+/-0.6 mm (y-axis) and 1.4+/-0.5 mm (x-axis). Median center deviation of the cutting ring was 2.6+/-0.8 mm.

CONCLUSIONS

The present study clearly confirmed ability of an accelerated cutting of stenotic aortic valve by the aortic valve resection tool. Nearly all leaflets were cut and a small rim was left within the annulus, hence providing an ideal 'landing zone' for the new prosthesis. Nevertheless, the aortic valve resection tool should be enhanced by adding a centering mechanism, thus achieving a more precise cutting process in order to avoid secondary damage.

Hemodynamic evaluation of aortic regurgitation by magnetic resonance imaging

Magnetic resonance imaging was compared with echocardiography and angiography in determining the regurgitant volume in patients with aortic regurgitation. Forty patients were examined at 1.5 T. The regurgitant jet was located using a gradient-echo sequence. Cine measurements were performed to calculate left ventricular function. For flow evaluation, a velocity-encoded breath-hold phase-difference magnetic resonance sequence was used. The degree of aortic regurgitation assessed by magnetic resonance imaging agreed with that of angiography in 28 of 40 (70%) patients, and with the echocardiography result in 80%. Correlation between calculated stroke volume by magnetic resonance cine and flow measurements was very good (r > 0.9). Magnetic resonance imaging enables quick and reliable quantitative assessment of aortic regurgitant volume, and it might be the optimal technique for multiple follow-up studies and assessment of left ventricular function, leading to better evaluation of disease severity and optimization of the timing of valve surgery.

Valve Pathology in Heart Failure: Which Valves Can Be Fixed?

Heart transplantation has evolved to become the gold standard treatment for patients who have symptoms of severe congestive heart failure associated with end-stage heart disease. From an epidemiologic perspective, this treatment is "trivial" because less than 2800 patients in the United States are offered transplantation because of limitations of age, comorbid conditions, and donor availability. New surgical strategies to manage patients who have severe end-stage heart disease have therefore evolved to cope with the donor shortage in heart transplantation and have included high-risk coronary artery revascularization, cardiomyoplasty, and high-risk valvular repair or replacement.

Vasodilator therapy in patients with aortic insufficiency: a systematic review

BACKGROUND

The use of vasodilators to improve long-term outcomes in asymptomatic patients with chronic aortic insufficiency (AI) is controversial.

METHODS

We reviewed MEDLINE, PREMEDLINE, Current Contents, and Cochrane databases to identify relevant clinical trials on asymptomatic patients with chronic AI of at least moderate severity. We included those studies that involved long-term vasodilator therapy (including hydralazine, calcium-channel blockers, and angiotensin-converting enzyme inhibitors) and assessed either hemodynamic and structural parameters or clinical outcomes. Data on patient demographics, study protocols, and outcomes were abstracted.

RESULTS

Ten studies with 544 asymptomatic patients with chronic AI were identified. Treatment duration with vasodilators ranged from 12 weeks to 7 years. Of these, 8 studies compared vasodilators with placebo or no therapy, with 5 demonstrating improvements in at least 1 hemodynamic or structural parameter with vasodilators and 3 showing little or no apparent benefit. The remaining 2 studies directly compared outcomes between 2 different vasodilators. Both of these studies demonstrated greater improvements in hemodynamic and structural parameters with angiotensin-converting enzyme inhibitors compared with hydralazine and nifedipine. Clinical outcomes were primarily reported in only 2 of the 10 studies. Although one study suggested that the use of vasodilators slowed the rate of progression to surgery for aortic valve replacement, another showed no difference.

CONCLUSIONS

Vasodilators inconsistently improve hemodynamic and structural parameters in asymptomatic patients with chronic AI. In addition, the impact of vasodilators on clinical outcomes is largely uncertain and requires further study.

Left ventricular remodelling index (LVRI) in various pathophysiological conditions: a real-time three-dimensional echocardiographic study

BACKGROUND

Various studies have reported a close correlation between real-time three-dimensional echocardiography (RT3DE) and cine magnetic resonance imaging studies for the assessment of cardiac volumes and mass.

OBJECTIVE

The aim of our study was to evaluate changes in left ventricular volumes and mass in subjects with different pathophysiological conditions. A ratio between left ventricular mass and end-diastolic volume (LVRI), detected by RT3DE, was used to describe various patterns of left ventricular remodelling.

METHODS

RT3DE was performed to calculate left ventricular end-diastolic (LVEDV) and end-systolic volume (LVESV), ejection fraction (LVEF) and mass in 220 selected subjects. Of these, 152 were healthy volunteers, 19 top-level rowers, 23 patients with dilated cardiomyopathy and 26 patients with hypertrophic cardiomyopathy. Off-line analysis was performed by two independent operators by tracing manual endocardial and epicardial borders of the left ventricle through eight cutting planes. Inter- and intra-observer variability were calculated.

RESULTS

Despite the increase in LV volume and mass in the rowers, LVRI remained unchanged compared with control subjects (p = 0.455), while significantly lower values were found patients with dilated cardiomyopathy (p<0.001) and significantly higher values in patients with hypertrophic cardiomyopathy (p<0.001). There was inter- and intra-observer variability.

CONCLUSION

The LVRI may serve as a simple and useful indicator of left ventricular adaptation to physiological and pathological conditions.

Long-term survival and functional results after aortic valve replacement in asymptomatic patients with chronic severe aortic regurgitation and left ventricular dysfunction

OBJECTIVES

We examined the influence of medical treatment on the results of surgery in terms of long-term survival and functional results in patients with chronic, severe aortic regurgitation (AR).

BACKGROUND

Asymptomatic patients with AR and a reduced left ventricular ejection fraction (LVEF) are at high risk because of a higher-than-expected long-term mortality. The influence of preoperative medical therapy on the outcome after aortic valve replacement (AVR) is not well known.

METHODS

Surgery was indicated for the appearance of a reduced LVEF (<50%). At the time of AVR, there were 134 patients treated with nifedipine (group A), and 132 received no medication (group B).

RESULTS

Operative mortality was similar in the two groups (0.75% vs. 0.76%, p = NS). The LVEF normalized in all of group A, whereas it remained abnormal in 36 group B patients (28%). At 10-year follow-up, LVEF persisted higher in group A (62 +/- 5% vs. 48 +/- 4%, p < 0.001). Five-year survival was similar in the two groups (94 +/- 2% vs. 94 +/- 3%, p = NS). Group A showed a 10-year survival not different from expected and significantly higher than that in group B (85 +/- 4% vs. 78 +/- 5%, p < 0.001), which had a worse survival than expected.

CONCLUSIONS

Unloading treatment with nifedipine in AR allows one to indicate AVR at the appearance of a reduced LVEF with a low operative mortality and an optimal long-term outcome. The concept of surgical correction of AR indicated for reduced LVEF may not be applied to all patients. Indeed, in a large amount of untreated patients, a reduced LVEF preoperatively is not reversed by prompt surgery, indicating irreversible myocardial damage, and 10-year survival is worse than expected.

Angiotensin-converting enzyme inhibitor captopril prevents volume overload cardiomyopathy in experimental chronic aortic valve regurgitation

The efficacy of angiotensin-converting enzyme inhibitors (ACEIs) in the treatment of chronic aortic regurgitation (AR) is not well established and remains controversial. The mechanisms by which ACEIs may protect against left-ventricular (LV) volume overload are not well understood, and clinical trials performed until now have yielded conflicting results. This study was therefore performed to assess the effectiveness of two different doses of the ACEI captopril in a rat model of chronic AR. We compared the effects of a 6-month low-dose (LD) (25 mg/kg) or higher dose (HD) (75 mg/kg) treatment with captopril on LV function and hypertrophy in Wistar rats with severe AR. Untreated animals developed LV eccentric hypertrophy and systolic dysfunction. LD treatment did not prevent hypertrophy and provided modest protection against systolic dysfunction. HD treatment preserved LV systolic function and dimensions and tended to slow hypertrophy. The cardiac index remained high and similar among all AR groups, treated or not. Tissue renin-angiotensin system (RAS) analysis revealed that ACE activity was increased in the LVs of AR animals and that only HD treatment significantly decreased angiotensin II receptor mRNA levels. Fibronectin expression was increased in the LV or AR animals, but HD treatment almost completely reversed this increase. The ACE inhibitor captopril was effective at high doses in this model of severe AR. These effects might be related to the modulation of tissue RAS and the control of fibrosis.