Comparison of grading of aortic stenosis between transthoracic and transesophageal echocardiography in adult patients undergoing elective aortic valve replacement surgeries: A prospective observational study.

INTRODUCTION

Intraoperative trans-esophageal echocardiography (TEE) has been found to underestimate severity of aortic stenosis (AS) compared to trans-thoracic echo (TTE). We conducted a prospective study comparing pre induction TTE and intra operative TEE grading of AS in patients posted for aortic valve replacement surgeries.

METHODS

Sixty patients with isolated AS who were undergoing aortic valve replacement were enrolled in our study. Baseline TTE was done and after induction of anesthesia, TEE was done. Mean gradient across aortic valve, peak jet velocity, aortic valve area (AVA) by continuity equation and dimensionless index (DI) were assessed in both.

RESULTS

Mean gradient decreased from 56.4 in TTE to 39.8 mm Hg in TEE leading to underestimation of AS in 74.5% of patients (P < 0.0). Mean of peak jet velocity also decreased from 500 in TTE to 386cm/s in TEE (P < 0.01). In 76 % of patients this led to reduction of AS grade from severe to moderate. Mean AVA was 0.67 cm in TTE and 0.69 cm in TEE. Though there was 0.02 cm increase, it was not statistically significant (P = 0.07). All the patients remained as severe AS in TEE. DI mean was 0.19 in both TTE and TEE (P = 0.14).It led to underestimation of severity in 6% of patients in TEE.

CONCLUSION

Our study shows that AVA measurement by continuity equation and DI are reliable in grading aortic stenosis while performing intraoperative TEE. Mean gradient and jet velocity can be significantly reduced.