Assessment of different calcification Criteria of the aortic valve for the determination of aortic stenosis severity

Background:

Some cases with severe Aortic Stenosis (AS) are misdiagnosed on Echocardiography such as low flow low gradient aortic stenosis, requiring the use of other methods for diagnosis, such as the examination of calcium amount on the aortic valve. This study aimed to determine the relationship between this value and the degree of aortic stenosis or valve area as measured by Echocardiography. The study also compared the accuracy of calcium scoring using the Agatston technique to a different threshold value for calcium inclusion.

Methods and results

Data from patients with available pre-TAVI-computed tomographic was collected retrospectively from April to December 2023. After exclusion, 63 patients were enrolled in the study (50.8% women, mean age 82.55 ± 5.57 years). The findings reveal strong relationships between AV peak and mean gradients and the standard index of aortic area at Hounsfield Unit (HU) thresholds of 130, 200, 500, more than 800, and 1000. We found no correlation between the degree of calcification and the aortic valve area (AVA). Additionally, using high HU shows no advantage in excluding the nearby structures.

Conclusion

The study emphasizes the reliability of calcification measurements as predictors of stenosis severity, but it also shows the limits associated with higher HU thresholds. This implies that higher thresholds may not capture the entire degree of calcification as the lower thresholds, so it is essential to choose the appropriate HU thresholds when evaluating aortic valve calcification and AS severity. We still recommend the usual care of using 130HU in detecting the severity of AS.