IMPACT OF SEX ON AORTIC VALVE CALCIFICATION AND FIBROSIS IN AORTIC STENOSIS

Calcium Scoring to Classify Aortic Valve Stenosis Severity: What Is the Current Data?

PURPOSE OF REVIEW

This review explores current clinical value of aortic valve calcification (AVC) in classifying aortic valve stenosis (AS) severity, refining patient's follow-up, as well as novel and potential applications of this highly accurate marker in improving outcomes for AS patients. AVC limitations and important particularities regarding sex, valve phenotype, and ethnicity will also be addressed.

RECENT FINDINGS

Sex-specific AVC cut-offs have been included in current guidelines to identify severe AS when echocardiography is inconclusive. AVC is also associated with AS progression and could help refine the timing for patient's follow-up. In patients with AS, Doppler echocardiography is the gold standard for the assessment of AS severity. However, in more than one-third of patients, echocardiographic parameters are discordant, casting shadow on the true severity of the disease. Considering active leaflet calcification is the driving mechanism of AS, quantification of AVC has been shown to be of great interest for distinguishing true-severe from pseudo-severe AS. Moreover, AVC is closely associated with AS progression and outcomes.

The effect of the fibrocalcific pathological process on aortic valve stenosis in female patients: a finite element study

Calcific aortic valve disease (CAVD) is the most common heart valvular disease in the developed world. Most of the relevant research has been sex-blind, ignoring sex-related biological variables and thus under-appreciate sex differences. However, females present pronounced fibrosis for the same aortic stenosis (AS) severity compared with males, who exhibit more calcification. Herein, we present a computational model of fibrocalcific AV, aiming to investigate its effect on AS development. A parametric study was conducted to explore the influence of the total collagen fiber volume and its architecture on the aortic valve area (AVA). Towards that goal, computational models were generated for three females with stenotic AVs and different volumes of calcium. We have tested the influence of fibrosis on various parameters as fiber architecture, fibrosis location, and transvalvular pressure. We found that increased fiber volume with a low calcium volume could actively contribute to AS and reduce the AVA similarly to high calcium volume. Thus, the computed AVAs for our fibrocalcific models were 0.94 and 0.84 cm²and the clinical (Echo) AVAs were 0.82 and 0.8 cm². For the heavily calcified model, the computed AVA was 0.8 cm²and the clinical AVA was 0.73 cm². The proposed models demonstrated how collagen thickening influence the fibrocalcific-AS process in female patients. These models can assist in the clinical decision-making process and treatment development in valve therapy for female patients.

Differences in mineral composition and morphology between men and women in aortic valve calcification

Aortic valve calcification leads to the deposition of calcium phosphate minerals in the extracellular matrix of the aortic valve leaflets. The mineral deposits can severely narrow the opening of the aortic valve, leading to aortic stenosis. There are no therapies to halt or slow down disease progression and the mechanisms governing aortic valve calcification are still poorly understood. Recently, several studies have shown that for the same aortic stenosis severity, women present significantly lower calcification loads than men. The cause of this sex-related difference is unknown. To understand this difference, we analyzed mineral deposits from surgically excised calcified human aortic valves with different material characterization techniques. We find profound differences in mineral composition and morphology between sexes, which strongly suggest that minerals form slower in women than in men and follow a different mineralization pathway. This finding paves the way for new approaches specifically geared towards men or women in the diagnosis and treatment of aortic valve calcification. STATEMENT OF SIGNIFICANCE: Aortic valve calcification is a health disorder with increasing prevalence and high morbidity and mortality. Currently there is no approved effective treatment; the only available therapeutic option is invasive valve replacement, to which not all patients are suited. The main reason for such lack of treatment options is our lack of understanding of the calcification mechanism. In this study, we show profound differences in mineral composition and morphology between sexes, suggesting that aortic valve calcification follows different mineralization pathways in men and women. These findings pave the way for new approaches specifically geared towards men or women in the diagnosis and treatment of aortic valve calcification.

Sex-specific aortic root anatomy in patients with bicuspid aortic valve undergoing TAVR in a Chinese cohort

Objectives

The aim of this study is to investigate the sex-specific aortic root anatomy in patients with bicuspid aortic valve (BAV).

Patients and methods

This retrospective study includes 73 consecutive patients with BAV who underwent CT evaluation before transcatheter aortic valve replacement (TAVR) between July 2013 and April 2017 in the Second Affiliated Hospital of Zhejiang University.

Result

The size of the annulus, diameter and height of the sinotubular junction (STJ), height of the coronary artery ostia, and dimension of the aorta were measured. Women had significantly smaller annulus parameters (mean diameter: 23.4 ± 1.8 vs. 26.1 ± 2.1 mm; area: 425.3 ± 59.4 vs. 527.4 ± 84.6 mm²; perimeter: 74.3 ± 5.2 vs. 83.2 ± 6.4 mm), and STJ diameter (29.7 ± 3.1 vs. 32.6 ± 4.5 mm) than men (p < 0.01 for all), even after adjustment for their smaller body surface area (BSA). Dimension of aorta and height of right coronary artery were also significantly smaller in women, although not when indexing for the BSA. The left ventricular ejection fraction of women is significantly higher than that of men before discharge (60.2 ± 9.7% vs. 53.7 ± 13.6%, p = 0.01). There were no differences between women and men in the all-cause 30-day and 1‑year mortality.

Conclusion

Women with BAV had smaller annulus and STJ diameter after indexing for BSA, reflecting a sex-specific difference. There were no differences in 30-day and 1‑year mortality between the two groups.

Electronic supplementary material

The online version of this article (10.1007/s00059-018-4740-0) contains supplementary material, which is available to authorized users.