The effect of transcatheter aortic valve implantation on intraoperative left ventricular myocardial performance index

Background and Goal of Study:
Transcatheter aortic valve implantation (TAVI) procedure for patients with aortic stenosis is expected to reduce left ventricular after load and following improvement of cardiac function. However, the effect of TAVI on intraoperative left ventricular global function including diastolic function gets less attention. 
Myocardial performance index (MPI) is an index that incorporates both systolic and diastolic time intervals in expressing global systolic and diastolic ventricular function.
This retrospective observational study is aimed to investigate the intraoperative left ventricular MPI to assess the effect of TAVI on left ventricular global function. 

Materials and Methods:
11 patients who underwent transfemoral TAVI procedure using SAPIEN XT valve under general anaesthesia were recruited in this study. 
Ejection time (ET), isovolumic contraction time (ICT), and isovolumic relaxation time (IRT) were measured from pulse wave tissue Doppler waveforms of mitral annulus obtained using TEE during TAVI procedure. MPI was calculated as (ICT＋IRT)/ET.
The MPI and Stroke volume before balloon aortic valvuloplasty and after prosthetic valve deployment were compared using paired t-test. Statistical significance was defined as the P value less than 0.05.

Results:
The MPI before balloon aortic valvuloplasty and after prosthetic valve deployment were 0.60±0.16 and 0.62±0.15, respectively. There were no significant differences.
ICT to IRT ratio before balloon aortic valvuloplasty was 1.48 ± 0.66, and significantly decreased to 1.13 ± 0.54 after prosthetic valve deployment. 

Conclusion:
TAVI procedure does not improve intraoperative left ventricular myocardial performance index just after prosthetic valve implantation.