RELATIONSHIP BETWEEN PROGRESSION OF AORTIC VALVE CALCIFICATION AND HEMODYNAMIC SEVERITY OF AORTIC STENOSIS: RESULTS FROM THE PROGRESSA STUDY

Clinical outcomes after aortic valve replacement with severe stenosis of trileaflet aortic valve and low valve calcium score

BACKGROUND

Some patients have severe aortic valve stenosis (AS) despite a lower degree of aortic valve calcification (AVC). This study compared the clinical features and prognosis of patients undergoing aortic valve replacement (AVR) for severe AS with a low AVC score compared with those with higher AVC scores.

METHODS

This study included 1002 Korean patients with symptomatic severe degenerative AS who underwent AVR. We measured AVC score before AVR and defined low AVC as AVC score of <2000 units for male patients and <1300 units for female patients. Patients with bicuspid or rheumatic aortic valve disease were excluded.

RESULTS

The mean age was 75.6±7.9 years and 487 patients (48.6%) were female. Mean left ventricular ejection fraction was 59.4%±10.4%, and concomitant coronary revascularisation was performed in 96 patients (9.6%). The median aortic valve calcium score was 3122 units (IQR 2249-4289 units) among male patients and 1756 units (IQR 1192-2572) among female patients. A total of 242 patients (24.2%) had low AVC; they were significantly younger (73.5±8.7 years vs 76.3±7.5 years, p<0.001) and were more likely to be female (59.5% vs 45.1%, p<0.001) and on haemodialysis (5.4% vs 1.8%, p=0.006) than those with high AVC. During a follow-up (median: 3.8 years), the patients with low AVC had significantly higher risk of death from any cause (adjusted HR 1.60, 95% CI 1.02 to 2.52, p=0.04), mostly non-cardiac cause.

CONCLUSIONS

Patients with low AVC exhibit distinct clinical characteristics and a higher risk of long-term mortality compared with those with high AVC.

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.