Sudden cardiac death in asymptomatic patients with aortic stenosis

Whole exome sequencing reveals genetic landscape associated with left ventricular outflow tract obstruction in Chinese Han population

Left ventricular outflow tract obstruction (LVOTO), a major form of outflow tract malformation, accounts for a substantial portion of congenital heart defects (CHDs). Unlike its prevalence, the genetic architecture of LVOTO remains largely unknown. To unveil the genetic mutations and risk genes potentially associated with LVOTO, we enrolled a cohort of 106 LVOTO patients and 100 healthy controls and performed a whole-exome sequencing (WES). 71,430 rare deleterious mutations were found in LVOTO patients. By using gene-based burden testing, we further found 32 candidate genes enriched in LVOTO patient including known pathological genes such as GATA5 and GATA6. Most variants of 32 risk genes occur simultaneously rather exclusively suggesting polygenic inherence of LVOTO and 14 genes out of 32 risk genes interact with previously discovered CHD genes. Single cell RNA-seq further revealed dynamic expressions of GATA5, GATA6, FOXD3 and MYO6 in endocardium and neural crest lineage indicating the mutations of these genes lead to LVOTO possibly through different lineages. These findings uncover the genetic architecture of LVOTO which advances the current understanding of LVOTO genetics.

Improving accuracy in diagnosing aortic stenosis severity: An in-depth analysis of echocardiographic measurement error through literature review and simulation study

AIMS

The present guidelines advise replacing the aortic valve for individuals with severe aortic stenosis (AS) based on various echocardiographic parameters. Accurate measurements are essential to avoid misclassification and unnecessary interventions. The objective of this study was to evaluate the influence of measurement error on the echocardiographic evaluation of the severity of AS.

METHODS AND RESULTS

A systematic review was performed to examine whether measurement errors are reported in studies focusing on the prognostic value of peak aortic jet velocity (Vmax ), mean pressure gradient (MPG), and effective orifice area (EOA) in asymptomatic patients with AS. Out of the 37 studies reviewed, 17 (46%) acknowledged the existence of measurement errors, but none of them utilized methods to address them. Secondly, the magnitude of potential errors was collected from available literature for use in clinical simulations. Interobserver variability ranged between 0.9% and 8.3% for Vmax and MPG but was higher for EOA (range 7.7%-12.7%), indicating lower reliability. Assuming a circular left ventricular outflow tract area led to a median underestimation of EOA by 23% compared to planimetry by other modalities. A clinical simulation resulted in the reclassification of 42% of patients, shifting them from a diagnosis of severe AS to moderate AS.

CONCLUSIONS

Measurement errors are underreported in studies on echocardiographic assessment of AS severity. These errors can lead to misclassification and misdiagnosis. Clinicians and scientists should be aware of the implications for accurate clinical decision-making and assuring research validity.

The Role of the Bicuspid Aortic Valve in Sudden Cardiac Death - Findings at Cardiac Autopsy

BACKGROUND

Bicuspid aortic valve (BAV) is the most common congenital cardiac defect in the adult population, with a prevalence of 0.5-2%. It is well recognised that aortic stenosis (AS), aortic regurgitation (AR) and aortopathy may develop by the fifth or sixth decade of life. There is a paucity of autopsy studies evaluating the hearts of subjects with BAV. The aim of this study is to help to ascertain the role of the bicuspid valve in the cause of sudden cardiac deaths.

METHODS

A database of 6325 whole hearts referred to a specialist cardiac pathology centre between 2004 and 2021 was reviewed to identify a subgroup of 91 subjects with a BAV reported. All cases had a negative full body autopsy and toxicology before being referred and subsequently underwent detailed cardiac evaluation including histological analysis by expert cardiac pathologists.

RESULTS

The mean age of death was 37±16 years (84% male). Death was attributed to aortic valve or aortic disease in 57% (n=52) of cases; AS 30% (n= 27), endocarditis 11% (n=10), aortic dissection (AD) 9% (n=8) and AR 8% (n=7). In the remaining 43% of cases, BAV was an incidental finding.

CONCLUSION

The majority of deaths in young individuals with BAV were attributed to complications related to the aortic valve or aorta indicating that BAV is not a benign condition. When a BAV is identified, individuals should be appropriately follow-up with imaging to inform the optimal timing of intervention before a complication develops that may predispose the individual to a premature death.

Early surgical intervention versus conservative management of asymptomatic severe aortic stenosis: a systematic review and meta-analysis

OBJECTIVE

Timing of intervention for patients with asymptomatic severe aortic stenosis (AS) remains controversial. To compare the outcomes of early aortic valve replacement (AVR) versus watchful waiting (WW) in patients with asymptomatic severe AS.

METHODS

We systematically searched PubMed, Embase and Cochrane databases, in December 2021, for studies comparing early AVR with WW in the treatment of asymptomatic severe AS. Random-effects meta-analysis was performed.

RESULTS

Twelve studies were included in which two were randomised clinical trials. A total of 4130 patients were included, providing a 1092 pooled death events. Our meta-analysis showed a significantly lower all-cause mortality for the early AVR compared with WW group, although with a high amount of heterogeneity between studies in the magnitude of the effect (pooled OR 0.40; 95% CI 0.35 to 0.45, p<0.01; I²=61%). An early surgery strategy displayed a significantly lower cardiovascular mortality (pooled OR 0.33; 95% CI 0.19 to 0.56, p<0.01; I²=64%) and heart failure hospitalisation (pooled OR 0.19; 95% CI 0.10 to 0.39, p<0.01, I²=7%). However, both groups had similar rates of stroke (pooled OR 1.30; 95% CI 0.73 to 2.29, p=0.36, I²=0%) and myocardial infarction (pooled OR 0.49; 95% CI 0.19 to 1.27, p=0.14, I²= 0%).

CONCLUSIONS

This study suggests that for patients with asymptomatic severe AS an early surgical intervention compared with a conservative WW strategy was associated with a lower heart failure hospitalisation and a similar rate of stroke or myocardial infarction, although with significant risk of bias.

PROSPERO REGISTRATION NUMBER

CRD42021291144.

Acute Decompensated Aortic Stenosis: State of the Art Review

Aortic stenosis (AS) is a progressive disease that carries a poor prognosis. Patients are managed conservatively until satisfying an indication for transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement (SAVR) based on AS severity and the presence of symptoms or adverse impact on the myocardium. Up to 1 in 3 TAVIs are performed for patients with acute symptoms of dyspnoea at rest, angina, and/or syncope - termed acute decompensated aortic stenosis (ADAS) and require urgent aortic valve replacement. These patients have longer hospital length of stay, undergo physical deconditioning, have a higher rate of acute kidney injury and mortality compared to stable patients with less severe symptoms. There is an urgent need to prevent ADAS and to deliver pathways to manage and improve ADAS-related outcomes. We provide here a contemporary review on epidemiological and pathophysiological aspects of ADAS, with a focus on the impact of ADAS from clinical and economic perspectives. We will offer also a global overview of the available evidence for treatment of ADAS and with priorities suggested for addressing current gaps in the literature and unmet clinical needs to improve outcomes for AS patients.

Interleukin 38 alleviates aortic valve calcification by inhibition of NLRP3

Calcific aortic valve disease (CAVD) is common in people over the age of 65. Progressive valvular calcification is a characteristic of CAVD and due to chronic inflammation in aortic valve interstitial cells (AVICs) resulting in CAVD progression. IL-38 is a naturally occurring anti-inflammatory cytokine; here, we report lower levels of endogenous IL-38 in AVICs isolated from patients' CAVD valves compared to AVICs from non-CAVD valves. Recombinant IL-38 suppressed spontaneous inflammatory activity and calcium deposition in cultured AVICs. In mice, knockdown of IL-38 enhanced the production of inflammatory mediators in murine AVICs exposed to the proinflammatory stimulant matrilin-2. We also observed that in cultured AVICs matrilin-2 stimulation activated the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome with procaspase-1 cleavage into active caspase-1. The addition of IL-38 to matrilin-2-treated AVICs suppressed caspase-1 activation and reduced the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, runt-related transcription factor 2, and alkaline phosphatase. Aged IL-38-deficient mice fed a high-fat diet exhibited aortic valve lesions compared to aged wild-type mice fed the same diet. The interleukin-1 receptor 9 (IL-1R9) is the putative receptor mediating the anti-inflammatory properties of IL-38; we observed that IL-1R9-deficient mice exhibited spontaneous aortic valve thickening and greater calcium deposition in AVICs compared to wild-type mice. These data demonstrate that IL-38 suppresses spontaneous and stimulated osteogenic activity in aortic valve via inhibition of the NLRP3 inflammasome and caspase-1. The findings of this study suggest that IL-38 has therapeutic potential for prevention of CAVD progression.

Antihypertensive treatment and risk factors for syncope in asymptomatic aortic stenosis patients with hypertension

BACKGROUND

Evidence for treating hypertension in patients with asymptomatic aortic valve stenosis(AS) is scarce.

OBJECTIVES

Given the paucity of data on the relationship between syncope and antihypertensive treatment in aortic stenosis. This study sought to investigate this association in patients admitted to our hospital.

METHODS

A total of 158 patients with asymptomatic moderate or severe aortic stenosis were analyzed. Follow-up was conducted by clinic visit, telephone contact, or review of electronic medical records. Outcomes were syncope.

RESULTS

Hypertension were documented in 90 of the 158 patients with moderate or severe AS, and 77 of them received antihypertensive medications. During an average 28 months follow-up period, the occurrence of syncope was observed in 13 patients. Among them, 8 were in antihypertensive group (n = 77) and 5 in normotensive group (n = 68). There was no significant difference in incidence of syncope between the two groups. Patients with treated hypertension and syncope had a lower stroke volume index (SVi), a higher valve arterial impedance (Z_VA), a smaller SAC than those without. Kaplan-Meier analysis showed that there was no significant difference in syncope cumulative incidence between antihypertensive group and normotensive group (log rank P = .478). Multivariate cox regression analysis showed that both Z_VA (hazard ratio:19.006, 95% confidence interval: 4.664 to77.448;P = .002) and LVMI (hazard ratio:1.484, 95% confidence interval: 1.427 to 5.157;P = .016) were associated with development of syncope, whereas hypertension were not related independently to syncope (hazard ratio:0.935, 95% confidence interval: 0.786 to3.173; P = .869).

CONCLUSIONS

In patients with moderate or severe AS, concomitant hypertension, and antihypertensive treatment didn't increase the occurrence of syncope, whereas higher Z_VA was independently associated with greater risk of syncope.

Timing of Intervention in Asymptomatic Patients with Aortic Stenosis

Aortic stenosis is a very common disease. Current guidelines recommend intervention mainly in symptomatic patients; aortic valve replacement can be considered in asymptomatic patients under specific conditions, but the evidence supporting these indications is poor. Continuous advances in both surgical and percutaneous techniques have substantially decreased rates of perioperative complications and mortality; with this in mind, many authors suggest that earlier intervention in patients with severe aortic stenosis, when they are still asymptomatic, may be indicated. This paper summarises what is known about the natural history of severe aortic stenosis and the scientific evidence available about the optimal timing for aortic valve replacement.

Left ventricular hypertrophy and sudden cardiac death

Sudden cardiac death (SCD) is among the leading causes of death worldwide, and it remains a public health problem, as it involves young subjects. Current guideline-directed risk stratification for primary prevention is largely based on left ventricular (LV) ejection fraction (LVEF), and preventive strategies such as implantation of a cardiac defibrillator (ICD) are justified only for documented low LVEF (i.e., ≤ 35%). Unfortunately, only a small percentage of primary prevention ICDs, implanted on the basis of a low LVEF, will deliver life-saving therapies on an annual basis. On the other hand, the vast majority of patients that experience SCD have LVEF > 35%, which is clamoring for better understanding of the underlying mechanisms. It is mandatory that additional variables be considered, both independently and in combination with the EF, to improve SCD risk prediction. LV hypertrophy (LVH) is a strong independent risk factor for SCD regardless of the etiology and the severity of symptoms. Concentric and eccentric LV hypertrophy, and even earlier concentric remodeling without hypertrophy, are all associated with increased risk of SCD. In this paper, we summarize the physiology and physiopathology of LVH, review the epidemiological evidence supporting the association between LVH and SCD, briefly discuss the mechanisms linking LVH with SCD, and emphasize the need to evaluate LV geometry as a potential risk stratification tool regardless of the LVEF.