Bicuspid and Unicuspid Aortic Valve: Fate of Moderate/Severe Mixed Aortic Valve Disease

Congenital heart disease: types, pathophysiology, diagnosis, and treatment options

Congenital heart disease (CHD) is a structural abnormality of the heart and/or great vessels and patients with CHD are at an increased risks of various morbidities throughout their lives and reduced long-term survival. Eventually, CHD may result in various complications including heart failure, arrhythmias, stroke, pneumonia, and sudden death. Unfortunately, the exact etiology and pathophysiology of some CHD remain unclear. Although the quality of life and prognosis of patients with CHD have significantly improved following technological advancement, the influence of CHD is lifelong, especially in patients with complicated CHD. Thus, the management of CHD remains a challenge due to its high prevalence. Finally, there are some disagreements on CHD among international guidelines. In this review, we provide an update of the pathophysiology, diagnosis, and treatment in most common type of CHD, including patent foramen ovale, atrial septal defect, ventricular septal defect, atrioventricular septal defect, patent ductus arteriosus, coarctation of the aorta, transposition of the great arteries, congenitally corrected transposition of the great arteries, coronary anomalies, left and right ventricular outflow tract obstruction, tetralogy of Fallot and Ebstein anomaly. In particular, we focus on what is known and what is unknown in these areas, aiming to improve the current understanding of various types of CHD.

Left ventricular reverse remodeling after aortic valve replacement or repair in bicuspid aortic valve with moderate or greater aortic regurgitation

Objective

Bicuspid aortic valve (AV) patients with aortic regurgitation (AR) differ from tricuspid AV patients given younger age, greater left ventricle (LV) compliance, and more prevalent aortic stenosis (AS). Bicuspid AV-specific data to guide timing of AV replacement or repair are lacking.

Methods

Adults with bicuspid AV and moderate or greater AR who underwent aortic valve replacement or repair at our center were studied. The presurgical echocardiogram, and echocardiograms within 3 years postoperatively were evaluated for LV geometry/function, and AV function. Semiquantitative AS/AR assessment was performed in all patients with adequate imaging.

Results

One hundred thirty-five patients (85% men, aged 44.5 ± 15.9 years) were studied (63% pure AR, 37% mixed AS/AR). Following aortic valve replacement or repair, change in LV end-diastolic dimension and change in LV end-diastolic volume were associated with preoperative LV end-diastolic dimension (β = 0.62 Δcm/cm; 95% CI, 0.43-0.73 Δcm/cm; P < .001), and LV end-diastolic volume (β = 0.6 ΔmL/mL; 95% CI, 0.4-0.7 ΔmL/mL; P < .001), respectively, each independent of AR/AS severity (P = not significant). Baseline LV size predicted postoperative normalization (LV end-diastolic dimension: odds ratio, 3.75/cm; 95% CI, 1.61-8.75/cm, LV end-diastolic volume: odds ratio, 1.01/mL; 95% CI, 1.004-1.019/mL, both P values < .01) whereas AR/AS severity did not (P = not significant). Indexed LV end diastolic volume outperformed LV end-diastolic dimension in predicting postoperative LV normalization (area under the curve = 0.74 vs 0.61) with optimal diagnostic cutoffs of 99 mL/m2 and 6.1 cm, respectively. Postoperative indexed LV end diastolic volume dilatation was associated with increased risk of death, transplant/ventricular assist device, ventricular arrhythmia, and reoperation (hazard ratio, 6.1; 95% CI, 1.7-21.5; P < .01).

Conclusions

Remodeling extent following surgery in patients with bicuspid AV and AR relates to preoperative LV size independent of valve disease phenotype or severity. Many patients with LV end-diastolic dimension below current surgical thresholds did not normalize LV size. LV volumetric assessment offered superior diagnostic performance for predicting residual LV dilatation, and postoperative indexed LV end diastolic volume dilatation was associated with adverse prognosis.

Mixed aortic stenosis and regurgitation: a clinical conundrum

Mixed aortic stenosis (AS) and aortic regurgitation (AR) is the most frequent concomitant valve disease worldwide and represents a heterogeneous population ranging from mild AS with severe AR to mild AR with severe AS. About 6.8% of patients with at least moderate AS will also have moderate or greater AR, and 17.9% of patients with at least moderate AR will suffer from moderate or greater AS. Interest in mixed AS/AR has increased, with studies demonstrating that patients with moderate mixed AS/AR have similar outcomes to those with isolated severe AS. The diagnosis and quantification of mixed AS/AR severity are predominantly echocardiography-based, but the combined lesions lead to significant limitations in the assessment. Aortic valve peak velocity is the best parameter to evaluate the combined haemodynamic impact of both lesions, with a peak velocity greater than 4.0 m/s suggesting severe mixed AS/AR. Moreover, symptoms, increased left ventricular wall thickness and filling pressures, and abnormal left ventricular global longitudinal strain likely identify high-risk patients who may benefit from closer follow-up. Although guidelines recommend interventions based on the predominant lesion, some patients could potentially benefit from earlier intervention. Once a patient is deemed to require intervention, for patients receiving transcatheter valves, the presence of mixed AS/AR could confer benefit to those at high risk of paravalvular leak. Overall, the current approach of managing patients based on the dominant lesion might be too reductionist and a more holistic approach including biomarkers and multimodality imaging cardiac remodelling and inflammation data might be more appropriate.

Impact of Left Ventricular Ejection Fraction on Clinical Outcomes in Bicuspid Aortic Valve Disease

BACKGROUND

The prognostic impact of left ventricular ejection fraction (LVEF) in patients with bicuspid aortic valve (BAV) disease has not been previously studied.

OBJECTIVES

The purpose of this study was to determine the prognostic impact of LVEF in BAV patients according to the type of aortic valve dysfunction.

METHODS

We retrospectively analyzed the data collected in 2,672 patients included in an international registry of patients with BAV. Patients were classified according to the type of aortic valve dysfunction: isolated aortic stenosis (AS) (n = 749), isolated aortic regurgitation (AR) (n = 554), mixed aortic valve disease (MAVD) (n = 190), or no significant aortic valve dysfunction (n = 1,179; excluded from this analysis). The study population was divided according to LVEF strata to investigate its impact on clinical outcomes.

RESULTS

The risk of all-cause mortality and the composite endpoint of aortic valve replacement or repair (AVR) and all-cause mortality increased when LVEF was <60% in the whole cohort as well as in the AS and AR groups, and when LVEF was <55% in MAVD group. In multivariable analysis, LVEF strata were significantly associated with increased rate of mortality (LVEF 50%-59%: HR: 1.83 [95% CI: 1.09-3.07]; P = 0.022; LVEF 30%-49%: HR: 1.97 [95% CI: 1.13-3.41]; P = 0.016; LVEF <30%: HR: 4.20 [95% CI: 2.01-8.75]; P < 0.001; vs LVEF 60%-70%, reference group).

CONCLUSIONS

In BAV patients, the risk of adverse clinical outcomes increases significantly when the LVEF is <60%. These findings suggest that LVEF cutoff values proposed in the guidelines to indicate intervention should be raised from 50% to 60% in AS or AR and 55% in MAVD.

Left ventricular remodelling in bicuspid aortic valve disease

AIMS

Characterization of left ventricular (LV) geometric pattern and LV mass could provide an important insight into the pathophysiological adaptations of the LV to pressure and/or volume overload in patients with bicuspid aortic valve (BAV) and significant (≥moderate) aortic valve (AV) disease. This study aimed to characterize LV remodelling and its prognostic impact in patients with BAV according to the predominant type of valvular dysfunction.

METHODS AND RESULTS

In this international, multicentre BAV registry, 1345 patients [51.0 (37.0-63.0) years, 71% male] with significant AV disease were identified. Patients were classified as having isolated aortic stenosis (AS) (n = 669), isolated aortic regurgitation (AR) (n = 499) or mixed aortic valve disease (MAVD) (n = 177). LV hypertrophy was defined as a LV mass index >115 g/m2 in males and >95 g/m2 in females. LV geometric pattern was classified as (i) normal geometry: no LV hypertrophy, relative wall thickness (RWT) ≤0.42, (ii) concentric remodelling: no LV hypertrophy, RWT >0.42, (iii) concentric hypertrophy: LV hypertrophy, RWT >0.42, and (iv) eccentric hypertrophy: LV hypertrophy, RWT ≤0.42. Patients were followed-up for the endpoints of event-free survival (defined as a composite of AV repair/replacement and all-cause mortality) and all-cause mortality. Type of AV dysfunction was related to significant variations in LV remodelling. Higher LV mass index, i.e. LV hypertrophy, was independently associated with the composite endpoint for patients with isolated AS [hazard ratio (HR) 1.08 per 25 g/m2, 95% confidence interval (CI) 1.00-1.17, P = 0.046] and AR (HR 1.19 per 25 g/m2, 95% CI 1.11-1.29, P < 0.001), but not for those with MAVD. The presence of concentric remodelling, concentric hypertrophy and eccentric hypertrophy were independently related to the composite endpoint in patients with isolated AS (HR 1.54, 95% CI 1.06-2.23, P = 0.024; HR 1.68, 95% CI 1.17-2.42, P = 0.005; HR 1.59, 95% CI 1.03-2.45, P = 0.038, respectively), while concentric hypertrophy and eccentric hypertrophy were independently associated with the combined endpoint for those with isolated AR (HR 2.49, 95% CI 1.35-4.60, P = 0.004 and HR 3.05, 95% CI 1.71-5.45, P < 0.001, respectively). There was no independent association observed between LV remodelling and the combined endpoint for patients with MAVD.

CONCLUSIONS

LV hypertrophy or remodelling were independently associated with the composite endpoint of AV repair/replacement and all-cause mortality for patients with isolated AS and isolated AR, although not for patients with MAVD.

Early Valve Replacement for Severe Aortic Valve Disease: Effect on Mortality and Clinical Ramifications

Timing of aortic valve intervention for chronic aortic regurgitation (AR) and/or aortic stenosis (AS) potentially affects long-term survival. The 2014 American Heart Association/American College of Cardiology (AHA/ACC) guidelines provide recommendations for the timing of intervention. Subsequent to the guidelines' release, several studies have been published that suggest a survival benefit from earlier timing of surgery for severe AR and/or AS. The aim of this review was to determine whether patients who have chronic aortic regurgitation (AR) and/or aortic stenosis (AS) have a survival benefit from earlier timing of aortic valve surgery. Medical databases were systematically searched from January 2015 to April 2020 for randomized controlled trials (RCTs) and observational studies that examined the timing of aortic valve replacement surgery for chronic AR and/or AS. For chronic AR, four observational studies and no RCTs were identified. For chronic AS, five observational studies, one RCT and one meta-analysis were identified. One observational study examining mixed aortic valve disease (MAVD) was identified. All of these studies, for AR, AS, and MAVD, found long-term survival benefit from timing of aortic valve surgery earlier than the current guidelines. Larger prospective RCTs are required to evaluate the benefit of earlier surgical intervention.