Comparison between aortic valve calcification and aortic valve calcification density in the assessment of aortic stenosis severity in a brazilian population

Abstract Introduction Aortic valve calcification (AVC) is a commonly used parameter to assess the severity of Aortic Stenosis (AS), particularly in cases of low-flow, low-gradient AS (LFLG) and in situations where there is diagnostic uncertainty. In general, AVC values above 1300 AU in women and 2000 AU in men are associated with severe AS. However, AVC does not account for the distribution of calcium within the aortic annulus or the size of the valve area, which can lead to misinterpretations. AVC density (AVCd), a parameter that relates AVC to the aortic annulus area (AA), has been proposed as a more accurate alternative, showing promising preliminary results. However, there is a lack of studies evaluating its clinical application. The aim of this study was to assess the values and correlation between AVC and AVCd in relation to severity of AS in a Brazilian population. Methods Single-center, retrospective study, 587 consecutive patients diagnosed with severe (451), moderate (71), and low-flow, low-gradient (LFLG) (65) aortic stenosis (AS). All patients underwent both echocardiography and aortic computed tomography (CT), with the procedures performed within a maximum of 12 months of each other. AVCd was calculated using the formula: AVC(AU)/AA(cm²). Results The median age of patients was 79 years (73-83), with 50.6% female. The median body surface area was 1.74 m² (1.59-1.88). Echocardiographic findings revealed a median left ventricular ejection fraction of 61% (55-66%), with a median aortic valve area of 0.7 cm² (range: 0.6-0.9), and an indexed area of 0.41 cm²/m² (0.35-0.50). On CT, the median AA was 4.48 cm² (3.92-5.1). The median AVC was 2449AU (1757-3588) in women and 3562AU (2338-5264) in men. Stratified by AS type, in women, the AVC was 1701AU (862-2267) in moderate, 2705AU (1928-3886) in severe, and 1678AU (1133-2235) in LFLG. In men, was 1953AU (1592-2974) in moderate, 4128AU (2910-5958) in severe, and 2238AU (1861-3384) in LFLG, with patterns consistent with the literature. The AVCd was 631 AU/cm² (447-890) in women and 739 AU/cm² (531-1022) in men. When stratified by AS type, in women, the AVCd was 431AU/cm² (245-594) in moderate, 677AU/cm² (503-970) in severe, and 398AU/cm² (281-570) in LFLG. In men, was 413AU/cm² (366-656) in moderate, 826AU/cm² (624-1152) in severe, and 465AU/cm² (373-644) in LFLG. In multivariate analysis, AVCd, rather than AVC, emerged as an independent and consistent factor across different models, correlating with the severity of AS, as assessed by the mean LV-Ao gradient (Figure 1). Conclusion These findings demonstrate that the AVCd exhibits a stronger and more consistent correlation with disease severity compared to the AVC. AVCd may serve as a more accurate and reliable tool for evaluating AS severity, particularly in complex cases such as LFLG. The observed differences between men and women emphasize the importance of considering population-specific factors when applying these methods in clinical practice.AVC and AVCd according to type of AS Multivariate analysis