Prognostic Implications of Bicuspid and Tricuspid Aortic Valve Phenotype on Progression of Moderate Aortic Stenosis and Ascending Aorta Dilatation

Impact of Moderate Aortic Stenosis on Long-Term Clinical Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

The clinical course of patients with moderate aortic stenosis (AS) remains incompletely defined.

OBJECTIVES

This study sought to analyze the clinical course of moderate AS and compare it with other stages of the disease.

METHODS

Multiple electronic databases were searched to identify studies on adult moderate AS. Random-effects models were used to derive pooled estimates. The primary endpoint was all-cause death. The secondary endpoints were cardiac death, heart failure, sudden death, and aortic valve replacement.

RESULTS

Among a total of 25 studies (12,143 moderate AS patients, 3.7 years of follow-up), pooled rates per 100 person-years were 9.0 (95% CI: 6.9 to 11.7) for all-cause death, 4.9 (95% CI: 3.1 to 7.5) for cardiac death, 3.9 (95% CI: 1.9 to 8.2) for heart failure, 1.1 (95% CI: 0.8 to 1.5) for sudden death, and 7.2 (95% CI: 4.3 to 12.2) for aortic valve replacement. Meta-regression analyses detected that diabetes (P = 0.019), coronary artery disease (P = 0.017), presence of symptoms (P < 0.001), and left ventricle (LV) dysfunction (P = 0.009) were associated with a significant impact on the overall estimate of all-cause death. All-cause mortality was higher in patients with reduced LV ejection fraction (<50%) than with normal LV ejection fraction: 16.5 (95% CI: 5.2 to 52.3) and 4.2 (95% CI: 1.4 to 12.8) per 100 person-years, respectively. Compared with moderate AS, the incidence rate difference of all-cause mortality was -3.9 (95% CI: -6.7 to -1.1) for no or mild AS and +2.2 (95% CI: +0.8 to +3.5) for severe AS patients.

CONCLUSIONS

Moderate AS appears to be associated with a mortality risk higher than no or mild AS but lower than severe AS, which increases in specific population subsets. The impact of early intervention in moderate AS patients having high-risk features deserves further investigation.

The mechanistic pathways of oxidative stress in aortic stenosis and clinical implications

Despite the elucidation of the pathways behind the development of aortic stenosis (AS), there remains no effective medical treatment to slow or reverse its progress. Instead, the gold standard of care in severe or symptomatic AS is replacement of the aortic valve. Oxidative stress is implicated, both directly as well as indirectly, in lipid infiltration, inflammation and fibro-calcification, all of which are key processes underlying the pathophysiology of degenerative AS. This culminates in the breakdown of the extracellular matrix, differentiation of the valvular interstitial cells into an osteogenic phenotype, and finally, calcium deposition as well as thickening of the aortic valve. Oxidative stress is thus a promising and potential therapeutic target for the treatment of AS. Several studies focusing on the mitigation of oxidative stress in the context of AS have shown some success in animal and in vitro models, however similar benefits have yet to be seen in clinical trials. Statin therapy, once thought to be the key to the treatment of AS, has yielded disappointing results, however newer lipid lowering therapies may hold some promise. Other potential therapies, such as manipulation of microRNAs, blockade of the renin-angiotensin-aldosterone system and the use of dipeptidylpeptidase-4 inhibitors will also be reviewed.