Angiotensin II receptor blockers are associated with reduced valvular fibrosis in females with aortic stenosis

Background Angiotensin receptor blockers (ARBs) may slow down the progression of aortic stenosis (AS), through their antifibrotic effect. Females present more valvular fibrosis than males, thus ARBs may have more effect in females. Our aim was to assess the impact of ARBs on the remodeling of the aortic valve in males and females. Methods We included patients who had an aortic valve replacement± coronary bypass grafting between 2006-2013. Patients with missing echocardiographic or histologic data were excluded. Warren-Yong and fibrosis scores of the explanted valves were performed. Patients were divided into four phenotypes according to their Warren-Yong and fibrosis scores: Mild calcification/fibrosis group, Severe calcification/fibrosis group, Predominant fibrosis group, Predominant calcification group. Results Among the 1,321 included patients, the vast majority (89%) has severe AS. Patients in the predominant fibrosis group, as compared to the predominant calcium group, were more often females (39 vs 31%, p=0.008), bicuspid valves (44 vs 34%, p=0.002) and they less often used ARBs (25 vs 30%, p=0.046). Female sex was independently associated with being in the predominant fibrosis group (OR 1.45 [95% CI 1.08-1.95], p=0.01), with a significant interaction between female sex and ARBs. Females taking ARBs compared to females not taking ARBs had significantly lower fibrosis score (p<0.001). This difference was not seen in males. Conclusion In this large series of patients with moderate-severe AS, among females there was a negative association between intake of ARBs and valvular fibrosis. Thus, the possible effects of ARBs may be sex-specific, with a larger therapeutic role in females.