Intraoperative Transesophageal and Postoperative Transthoracic Echocardiographic Evaluation of a Mechanical Heart Valve Prosthesis Implanted at Aortic Position.

ABSTRACT

OBJECTIVE: The aims of this study were to evaluate the intraoperative transesophageal echocardiographic (iTEE) characteristics and Doppler flow profile of aortic Chitra heart valve prosthesis (CHVP) under stable hemodynamic and loading conditions, and to compare and correlate the iTEE data with the postoperative transthoracic echocardiography (TTE) data obtained at 48 hours (TTE1) and 3 months (TTE2) after the surgery. DESIGN: Prospective, observational study. SETTING: University-level tertiary referral hospital. PARTICIPANTS: Forty patients between 18 years and 65 years of age undergoing elective aortic valve replacement (AVR) using CHVP during the period January 2015 to August 2016. INTERVENTIONS: After obtaining permission from institutional ethics committee, 40 patients undergoing elective AVR were studied prospectively. The iTEE examination was performed in the pre-cardiopulmonary bypass (CPB) and post-CPB period in all the study subjects. CHVP was subjected to iTEE two-dimensional (2D) echo, color Doppler, and spectral Doppler evaluation under stable hemodynamic and loading condition in the post-CPB period after the administration of protamine. The CHVP were re-evaluated using TTE in all the patients 48 hours after the surgery (TTE1) and 3 months after the surgery (TTE2). The iTEE and postoperative TTE Doppler values were compared and correlated. MEASUREMENTS AND MAIN RESULTS: The CHVP could be imaged adequately and interrogated with Doppler in all the patients. None of the patients had restriction of occluder mobility or unstable seating of the valve. The intraoperative flow dependent (peak velocity [PV] and mean pressure gradient [MPG]) and less flow dependent (Doppler velocity index, acceleration time, acceleration time/ejection time, effective orifice area [EOA] and indexed EOA) Doppler parameters of CHVP were measured as per the American Society of Echocardiography recommendations. The PV and MPG of CHVP measured by iTEE showed no statistical difference (p > 0.05) and were in limits of agreement when compared with TTE1 and TTE2 data. CONCLUSION: The iTEE features of CHVP were found compliant with the criteria set by the ASE defining normal functioning of an aortic valve prosthesis. The iTEE Doppler parameters obtained under stable loading conditions strongly predicted the postoperative values of Doppler parameters on TTE examination. The iTEE Doppler values can be used as the reference values for the postoperative follow up studies.