Quantification of aortic valve area at 256-slice computed tomography: comparison with transesophageal echocardiography and cardiac catheterization in subjects with high-grade aortic valve stenosis prior to percutaneous valve replacement.

PURPOSE

The purpose of this study was to compare planimetric aortic valve area (AVA) measurements from 256-slice CT to those derived from transesophageal echocardiography (TEE) and cardiac catheterization in high-risk subjects with known high-grade calcified aortic stenosis.

METHODS AND MATERIALS

The study included 26 subjects (10 males, mean age: 79±6; range, 61-88 years). All subjects were clinically referred for aortic valve imaging prior to percutaneous aortic valve replacement from April 2008 to March 2009. Two radiologists, blinded to the results of TEE and cardiac catheterization, independently selected the systolic cardiac phase of maximum aortic valve area and independently performed manual CT AVA planimetry for all subjects. Repeated AVA measurements were made to establish CT intra- and interobserver repeatability. In addition, the image quality of the aortic valve was rated by both observers. Aortic valve calcification was also quantified.

RESULTS

All 26 subjects had a high-grade aortic valve stenosis (systolic opening area <1.0 cm(2)) via CT-based planimetry, with a mean AVA of 0.62±0.18. In four subjects, TEE planimetry was precluded due to severe aortic valve calcification, but CT-planimetry was successfully performed with a mean AVA of 0.46±0.23 cm(2). Mean aortic valve calcium mass score was 563.8±526.2 mg. Aortic valve area by CT was not correlated with aortic valve calcium mass score. A bias and limits of agreement among CT and TEE, CT and cardiac catheterization, and TEE and cardiac catheterization were -0.07 [-0.37 to 0.24], 0.03 [-0.49 to 0.55], 0.12 [-0.39 to 0.63]cm(2), respectively. Differences in AVA among CT and TEE or cardiac catheterization did not differ systematically over the range of measurements and were not correlated with aortic valve calcium mass score.

CONCLUSION

Planimetric aortic valve area measurements from 256-slice CT agree well with those derived from TEE and cardiac catheterization in high-risk subjects with known high-grade calcified aortic stenosis.