Differences at surgery between patients with bicuspid and tricuspid aortic valves

The Prevalence of Coronary Artery Disease in Bicuspid Aortic Valve Patients: An Overview of the Literature

The prevalence of coronary artery disease (CAD) in bicuspid aortic valve (BAV) patients is a debatable topic. Several studies have indicated that BAV patients have a lower prevalence of CAD compared with patients with a tricuspid aortic valve (TAV), but the effects of age and gender have not always been considered. This systematic review provides an overview of articles which report on CAD in BAV and TAV patients. Searches were executed in April 2021 and January 2022 according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) guidelines in three online databases: Medline, Embase, and Scopus. Screening and data extraction was done by two investigators separately. Primary and secondary outcomes were compared between BAV and TAV patients; a fixed effects model was used for correcting on confounders. Literature search yielded 1,529 articles with 44 being eligible for inclusion. BAV patients were younger (56.4 ± 8.3 years) than TAV patients (64 ± 10.3 years, p < 0.001). All CAD risk factors and CAD were more prevalent in TAV patients. No significant difference remained after correcting for age and gender as confounders. BAV patients have a lower prevalence of CAD and CAD risk factors compared with TAV patients. However, when the age differences between both groups are considered in the analyses, a similar prevalence of both CAD and CAD risk factors is found.

The effects of strain history on aortic valve interstitial cell activation in a 3D hydrogel environment

Aortic valves (AVs) undergo unique stretch histories that include high rates and magnitudes. While major differences in deformation patterns have been observed between normal and congenitally defective bicuspid aortic valves (BAVs), the relation to underlying mechanisms of rapid disease onset in BAV patients remains unknown. To evaluate how the variations in stretch history affect AV interstitial cell (AVIC) activation, high-throughput methods were developed to impart varied cyclical biaxial stretch histories into 3D poly(ethylene) glycol hydrogels seeded with AVICs for 48 h. Specifically, a physiologically mimicking stretch history was compared to two stretch histories with varied peak stretch and stretch rate. Post-conditioned AVICs were imaged for nuclear shape, alpha smooth muscle actin (αSMA) and vimentin (VMN) polymerization, and small mothers against decapentaplegic homologs 2 and 3 (SMAD 2/3) nuclear activity. The results indicated that bulk gel deformations were accurately transduced to the AVICs. Lower peak stretches lead to increased αSMA polymerization. In contrast, VMN polymerization was a function of stretch rate, with SMAD 2/3 nuclear localization and nuclear shape also trending toward stretch rate dependency. Lower than physiological levels of stretch rate led to higher SMAD 2/3 activity, higher VMN polymerization around the nucleus, and lower nuclear elongation. αSMA polymerization did not correlate with VMN polymerization, SMAD 2/3 activity, nor nuclear shape. These results suggest that a negative feedback loop may form between SMAD 2/3, VMN, and nuclear shape to maintain AVIC homeostatic nuclear deformations, which is dependent on stretch rate. These novel results suggest that AVIC mechanobiological responses are sensitive to stretch history and provide insight into the mechanisms of AV disease.

Surgical aortic valve replacement in the era of transcatheter aortic valve implantation: a review of the UK national database

OBJECTIVES

To date the reported outcomes of surgical aortic valve replacement (SAVR) are mainly in the settings of trials comparing it with evolving transcatheter aortic valve implantation. We set out to examine characteristics and outcomes in people who underwent SAVR reflecting a national cohort and therefore 'real-world' practice.

DESIGN

Retrospective analysis of prospectively collected data of consecutive people who underwent SAVR with or without coronary artery bypass graft (CABG) surgery between April 2013 and March 2018 in the UK. This included elective, urgent and emergency operations. Participants' demographics, preoperative risk factors, operative data, in-hospital mortality, postoperative complications and effect of the addition of CABG to SAVR were analysed.

SETTING

27 (90%) tertiary cardiac surgical centres in the UK submitted their data for analysis.

PARTICIPANTS

31 277 people with AVR were identified. 19 670 (62.9%) had only SAVR and 11 607 (37.1%) had AVR+CABG.

RESULTS

In-hospital mortality for isolated SAVR was 1.9% (95% CI 1.6% to 2.1%) and was 2.4% for AVR+CABG. Mortality by age category for SAVR only were: <60 years=2.0%, 60-75 years=1.5%, >75 years=2.2%. For SAVR+CABG these were; 2.2%, 1.8% and 3.1%. For different categories of EuroSCORE, mortality for SAVR in low risk people was 1.3%, in intermediate risk 1% and for high risk 3.9%. 74.3% of the operations were elective, 24% urgent and 1.7% emergency/salvage. The incidences of resternotomy for bleeding and stroke were 3.9% and 1.1%, respectively. Multivariable analyses provided no evidence that concomitant CABG influenced outcome. However, urgency of the operation, poor ventricular function, higher EuroSCORE and longer cross clamp and cardiopulmonary bypass times adversely affected outcomes.

CONCLUSIONS

Surgical SAVR±CABG has low mortality risk and a low level of complications in the UK in people of all ages and risk factors. These results should inform consideration of treatment options in people with aortic valve disease.

Comparative evaluation of coronary disease burden: bicuspid valve disease is not atheroprotective

OBJECTIVE

Bicuspid aortic valve (BAV) has been associated with less atherosclerosis as compared with tricuspid aortic valve (TAV) patients. It, however, remains unclear whether this reflects the older age of TAV patients and/or accumulation of atherosclerotic risk factors or that the BAV phenotype is atheroprotective. Therefore, we compared the atherosclerotic disease burden of BAV and TAV patients, with that of the general (age-matched) population.

METHODS

The prevalence of coronary artery disease (CAD) and CAD risk factors in BAV and TAV patients who underwent aortic valve surgery were compared with the Dutch general practitioners registry data. BAV (n=454) and TAV (n=1101) patients were divided into four groups: BAV with aortic valve stenosis (BAV-AoS), BAV with aortic valve regurgitation (BAV-AR), TAV with AoS (TAV-AoS) and TAV with AR (TAV-AR). The atherosclerotic disease burden of each group was compared with that of the corresponding age cohort for the general population.

RESULTS

CAD risk factors hypertension and hypercholesterolaemia were more prevalent in the surgery groups than the age-matched general population (all p<0.001). All BAVs (BAV-AoS and BAV-AR) and TAV-AR had a similar incidence of CAD history as compared to the age-matched general populations (p=0.689, p=0.325 and p=0.617 respectively), whereas TAV-AoS had a higher incidence (21.6% versus 14.9% in the age-matched general population, p<0.001).

CONCLUSIONS

Stenotic TAV disease is part of the atherosclerotic disease spectrum, while regurgitant TAV and all BAVs are not. Although the prevalence of cardiovascular risk factors is higher in all BAV patients, the prevalence of CAD is similar to the general population.

Differences in baseline characteristics and outcomes of bicuspid and tricuspid aortic valves in surgical aortic valve replacement

OBJECTIVES

Patients with bicuspid aortic valve (BAV) comprise a substantial portion of patients undergoing surgical aortic valve replacement (SAVR). Our goal was to quantify the prevalence of BAV in the current SAVR ± coronary artery bypass grafting (CABG) population, assess differences in cardiovascular risk profiles and assess differences in long-term survival in patients with BAV compared to patients with tricuspid aortic valve (TAV).

METHODS

Patients who underwent SAVR with or without concomitant CABG and who had a surgical report denoting the relevant valvular anatomy were eligible and included. Prevalence, predictors and outcomes for patients with BAV were analysed and compared to those patients with TAV. Matched patients with BAV and TAV were compared using a propensity score matching strategy and an age matching strategy.

RESULTS

A total of 3723 patients, 3145 of whom (mean age 66.6 ± 11.4 years; 37.4% women) had an operative report describing their aortic valvular morphology, underwent SAVR ± CABG between 1987 and 2016. The overall prevalence of patients with BAV was 19.3% (607). Patients with BAV were younger than patients with TAV (60.6 ± 12.1 vs 68.0 ± 10.7, respectively). In the age-matched cohort, patients with BAV were less likely to have comorbidities, among others diabetes (P = 0.001), hypertension (P < 0.001) and hypercholesterolaemia (P = 0.003), compared to patients with TAV. Twenty-year survival following the index procedure was higher in patients with BAV (14.8%) compared to those with TAV (12.9%) in the age-matched cohort (P = 0.015).

CONCLUSIONS

Substantial differences in the cardiovascular risk profile exist in patients with BAV and TAV. Long-term survival after SAVR in patients with BAV is satisfactory.

Comparison of Clinical and Echocardiographic Features of Asymptomatic Patients With Stenotic Bicuspid Versus Tricuspid Aortic Valves

The clinical and imaging differences between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) patients with medically managed asymptomatic moderate-to-severe aortic stenosis (AS) have not been studied previously. We aim to characterize these differences and their clinical outcomes in this study. A retrospective observational study was conducted on 836 consecutive cases of isolated asymptomatic moderate-to-severe AS, with median follow-up of 3.4 years. Clinical and echocardiographic characteristics were compared between BAV and TAV patients. Subgroup analysis stratified by AS severity were performed. Survival analysis of all-cause mortality was performed using Kaplan-Meier curves and Cox proportional hazards model. Compared to BAV patients, TAV patients were older (76 ± 11 vs 55 ± 16 years, p <0.001) and had more co-morbidities including hypertension (78% vs 56%; p <0.001), diabetes (41% vs 24%; p <0.001), and chronic kidney disease (20% vs 3%; p = 0.001). TAV patients had less severe aortic valve disease than BAV patients, with a higher aortic valve area index (0.71 ± 0.20 cm²/m² vs 0.61 ± 0.18 cm²/m², p <0.001) and less aortic dilation (sinotubular junction: 23.7 ± 4.0 mm vs 26.9 ± 4.8 mm, p <0.001; mid-ascending aorta: 31.4 ± 4.7 mm vs 36.3 ± 6.3 mm, p <0.001). TAV patients were more likely to have eccentric left ventricular hypertrophy and less likely to have a normal geometry (p = 0.003). Competing risk analysis identified increased age (hazard ratio 1.03, 95% confidence interval 1.02 to 1.05, p <0.001) and LVEF (hazard ratio 0.98, 95% confidence interval 0.97 to 0.99, p <0.001) as independent risk factors of all-cause mortality. Valve morphology was not a significant independent risk factor for aortic valve replacement or mortality. In conclusion, asymptomatic TAV patients had more cardiovascular risk factors, less severe aortic valve disease, less sinotubular and mid-ascending aortic dilation, more severe LV remodeling.