Decision Making With Imaging in Asymptomatic Aortic Regurgitation

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.

Sex-based differences in left ventricular remodeling in patients with chronic aortic regurgitation: a multi-modality study

BACKGROUND

Significant aortic regurgitation (AR) leads to left ventricular (LV) remodeling; however, little data exist regarding sex-based differences in LV remodeling in this setting. We sought to compare LV remodeling and AR severity, assessed by echocardiography and cardiovascular magnetic resonance (CMR), to discern sex-based differences.

METHODS

Patients with ≥ moderate chronic AR by echocardiography who underwent CMR within 90 days between December 2005 and October 2015 were included. Nonlinear regression models were built to assess the effect of AR regurgitant fraction (RF) on LV remodeling. A generalized linear model and Bland Altman analyses were constructed to evaluate differences between CMR and echocardiography. Referral for surgical intervention based on symptoms and LV remodeling was evaluated.

RESULTS

Of the 243 patients (48.3 ± 16.6 years, 58 (24%) female), 119 (49%) underwent surgical intervention with a primary indication of severe AR, 97 (82%) men, 22 (18%) women. Significant sex differences in LV remodeling emerged on CMR. Women demonstrated significantly smaller LV end-diastolic volume index (LVEDVI) (96.8 ml/m2 vs 125.6 ml/m2, p < 0.001), LV end-systolic volume index (LVESVI) (41.1 vs 54.5 ml/m2, p < 0.001), blunted LV dilation in the setting of increasing AR severity (LVEDVI p value < 0.001, LVESVI p value 0.011), and LV length indexed (8.32 vs 9.69 cm, p < 0.001). On Bland Altman analysis, a significant interaction with sex and LV diameters was evident, demonstrating a significant increase in the difference between CMR and echocardiography measurements as the LV enlarged in women: LVEDVI (p = 0.006), LVESVI (p < 0.001), such that echocardiographic measurements increasingly underestimated LV diameters in women as the LV enlarged. LV length was higher for males with a linear effect from RF (p < 0.001), with LV length increasing at a higher rate with increasing RF for males compared to females (two-way interaction with sex p = 0.005). Sphericity volume index was higher for men after adjusting for a relative wall thickness (p = 0.033).

CONCLUSIONS

CMR assessment of chronic AR revealed significant sex differences in LV remodeling and significant echocardiographic underestimation of LV dilation, particularly in women. Defining optimal sex-based CMR thresholds for surgical referral should be further developed.

TRIAL REGISTRATION

NA.

Multimodality imaging in valvular heart disease: how to use state-of-the-art technology in daily practice

Our understanding of the complexities of valvular heart disease (VHD) has evolved in recent years, primarily because of the increased use of multimodality imaging (MMI). Whilst echocardiography remains the primary imaging technique, the contemporary evaluation of patients with VHD requires comprehensive analysis of the mechanism of valvular dysfunction, accurate quantification of severity, and active exclusion extravalvular consequences. Furthermore, advances in surgical and percutaneous therapies have driven the need for meticulous multimodality imaging to aid in patient and procedural selection. Fundamental decision-making regarding whom, when, and how to treat patients with VHD has become more complex. There has been rapid technological advancement in MMI; many techniques are now available in routine clinical practice, and their integration into has the potential to truly individualize management strategies. This review provides an overview of the current evidence for the use of MMI in VHD, and how various techniques within each modality can be used practically to answer clinical conundrums.

Prognostic significance of myocardial fibrosis and CMR characteristics in bicuspid aortic valve with moderate and severe aortic insufficiency

OBJECTIVES

This study attempted to evaluate the characteristics and prognostic value of myocardial fibrosis (MF) in aortic insufficiency (AI) patients with bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) by cardiac magnetic resonance (CMR).

METHODS

A total of 314 adults with CMR-diagnosed AI were retrospectively retrieved. Of them, 166 patients with moderate or severe AI were included and divided into two groups: BAV group (N = 46) and a TAV group (N = 120). The presence and characteristics of MF were assessed with CMR. The patients were followed for adverse clinical events. The prognostic capability of the parameters was assessed using Cox regression model.

RESULTS

LV fibrosis was more common in the BAV group than in the TAV group (65.2% vs. 45.0%; p = 0.020). There was a strong association between BAV and MF even after adjusting for clinical and imaging variables (odds ratio: 3.57; p = 0.031). Kaplan-Meier analysis showed a higher rate of clinical adverse events in AI+BAV patients with MF during a median follow-up of 4.7 years. Multivariate Cox regression analysis showed that late gadolinium enhancement (LGE) was an independent predictor of clinical adverse outcome.

CONCLUSION

MF is more common in AI with BAV than with TAV and is a predictor of clinical adverse events.

KEY POINTS

• The presence and extent of late gadolinium enhancement of left ventricular were more common and severer in the bicuspid aortic valve group than in the tricuspid aortic valve group in aortic insufficiency patients. • Bicuspid aortic valve was an independent factor for myocardial fibrosis in aortic insufficiency patients. • Late gadolinium enhancement could be used as an independent predictor of adverse clinical events in this population.

Prognostic implications of left atrial dilation in aortic regurgitation due to bicuspid aortic valve

OBJECTIVE

To investigate the prognostic value of left atrial volume index (LAVI) in patients with moderate to severe aortic regurgitation (AR) and bicuspid aortic valve (BAV).

METHODS

554 individuals (45 (IQR 33-57) years, 80% male) with BAV and moderate or severe AR were selected from an international, multicentre registry. The association between LAVI and the combined endpoint of all-cause mortality or aortic valve surgery was investigated with Cox proportional hazard regression analyses.

RESULTS

Dilated LAVI was observed in 181 (32.7%) patients. The mean indexed aortic annulus, sinus of Valsalva, sinotubular junction and ascending aorta diameters were 13.0±2.0 mm/m², 19.4±3.7 mm/m², 16.5±3.8 mm/m² and 20.4±4.5 mm/m², respectively. After a median follow-up of 23 (4-82) months, 272 patients underwent aortic valve surgery (89%) or died (11%). When compared with patients with normal LAVI (<35 mL/m²), those with a dilated LAVI (≥35 mL/m²) had significantly higher rates of aortic valve surgery or mortality (43% and 60% vs 23% and 36%, at 1 and 5 years of follow-up, respectively, p<0.001). Dilated LAVI was independently associated with reduced event-free survival (HR=1.450, 95% CI 1.085 to 1.938, p=0.012) after adjustment for LV ejection fraction, aortic root diameter, LV end-diastolic diameter and LV end-systolic diameter.

CONCLUSIONS

In this large, multicentre registry of patients with BAV and moderate to severe AR, left atrial dilation was independently associated with reduced event-free survival. The role of this parameter for the risk stratification of individuals with significant AR merits further investigation.

Association of Echocardiographic Left Ventricular End-Systolic Volume and Volume-Derived Ejection Fraction With Outcome in Asymptomatic Chronic Aortic Regurgitation

Importance

Volumetric measurements by transthoracic echocardiogram may better reflect left ventricular (LV) remodeling than conventional linear LV dimensions. However, the association of LV volumes with mortality in patients with chronic hemodynamically significant aortic regurgitation (AR) is unknown.

Objective

To assess whether LV volumes and volume-derived LV ejection fraction (Vol-LVEF) are determinants of mortality in AR.

Design, Setting, and Participants

This cohort study included consecutive asymptomatic patients with chronic moderately severe to severe AR from a tertiary referral center (January 2004 through April 2019).

Exposures

Clinical and echocardiographic data were analyzed retrospectively. Aortic regurgitation severity was graded by comprehensive integrated approach. De novo disk-summation method was used to derive LV volumes and Vol-LVEF.

Main Outcome and Measures

Associations between all-cause mortality under medical surveillance and the following LV indexes: linear LV end-systolic dimension index (LVESDi), linear LVEF, LV end-systolic volume index (LVESVi), and Vol-LVEF.

Results

Of 492 asymptomatic patients (mean [SD] age, 60 [17] years; 425 men [86%]), ischemic heart disease prevalence was low (41 [9%]), and 453 (92.1%) had preserved linear LVEF (≥50%) with mean (SD) LVESVi of 41 (15) mL/m2. At a median (interquartile range) of 5.4 (2.5-10.1) years, 66 patients (13.4%) died under medical surveillance; overall survival was not different than the age- and sex-matched general population (P = .55). Separate multivariate models, adjusted for age, sex, Charlson Comorbidity Index, and AR severity, demonstrated that in addition to linear LVEF and LVESDi, LVESVi and Vol-LVEF were independently associated with mortality under surveillance (all P < .046) with similar C statistics (range, 0.83-0.84). Spline curves showed that continuous risks of death started to rise for both linear LVEF and Vol-LVEF less than 60%, LVESVi more than 40 to 45 mL/m2, and LVESDi above 21 to 22 mm/m2. As dichotomized variables, patients with LVESVi more than 45 mL/m2 exhibited increased relative death risk (hazard ratio, 1.93; 95% CI, 1.10-3.38; P = .02) while LVESDi more than 20 mm/m2 did not (P = .32). LVESVi more than 45 mL/m2 showed a decreased survival trend compared with expected population survival.

Conclusions and Relevance

In this large asymptomatic cohort of patients with hemodynamically significant AR, LVESVi and Vol-LVEF worked equally as well as LVESDi and linear LVEF in risk discriminating patients with excess mortality. A LVESVi threshold of 45 mL/m2 or greater was significantly associated with an increased mortality risk.

State of the Art Management of Aortic Valve Disease in Ankylosing Spondylitis

PURPOSE OF REVIEW

Cardiac involvement in patients with ankylosing spondylitis (AS) generally manifests itself as aortic insufficiency, aortitis, disturbance in cardiac conduction, and myocardial dysfunction. We have used a case-based approach to review the current state of the art knowledge regarding the diagnosis and management of aortic valve disease and aortitis in patients with AS.

RECENT FINDINGS

The risk for aortic valve disease and aortic valve replacement or repair is significantly higher than in people without AS, and this risk increases with age. Echocardiography, cardiac MRI, and CT can serve as effective tools for screening and follow-up. Surgical repair/replacement remains the mainstay of therapy for aortic insufficiency and aortic dilation, whereas transcatheter-based techniques may be favorable in the setting of aortic stenosis. Aortic valve and atrioventricular conduction abnormalities contribute to overall cardiovascular burden in AS. Optimal timing and therapeutic technique are dependent on assessment of overall risk and serial follow-up.

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.

Contemporary Etiologies, Mechanisms, and Surgical Approaches in Pure Native Aortic Regurgitation

OBJECTIVE

To study contemporary etiologies, mechanisms, and corresponding surgical approaches in isolated aortic regurgitation (AR).

PATIENTS AND METHODS

Consecutive patients undergoing surgery for moderately severe and severe AR were retrospectively identified from January 1, 2006, through October 20, 2017. Intraoperative echocardiograms, surgical reports, and pathology reports were reviewed.

RESULTS

Of 382 patients (54±16 years, 82% men), there were 207 (54%) tricuspid (TAV), 167 (44%) bicuspid (BAV), 5 quadricuspid, and 3 unicuspid aortic valves. Isolated AR mechanisms (n=116, 30%) included cusp prolapse (n=44, 11%), restriction/retraction (n=33, 9%), aortic root dilatation (n=33, 9%), perforation (n=5, 1%), and fenestration (<1%); mixed mechanisms were present in 266 (70%). The most common mixed mechanism was root dilatation and prolapse (27% BAV vs 16% TAV, P=.01). Valve repair (AVr) was performed in 31% BAV and 23% TAV (P=.06). Aortic surgery was more common in BAV (37% vs 27%, P<.001). Overall, root dilatation was associated with AVr. In TAV, cusp prolapse and restriction/retraction were associated with replacement; in BAV, prolapse was associated with AVr. AR etiology was idiopathic in 43% TAV patients, 47% of whom had root dilatation.

CONCLUSIONS

BAV accounted for 44% of surgical referrals for AR and, compared with TAV, was more often associated with prolapse, root dilatation, and mixed mechanisms of AR. Because mechanisms affected the choice of AVr differently in BAV and TAV, comprehensive mechanistic description of surgical AR is critical.