Abstract 2709: Saline Injection Test (SIT) May Provide Inaccurate Evaluation of Mitral-Left Ventricular (LV) Dimension During Mitral Valve Plasty (MVP)
Introduction : SIT during MVP has been popular; however, geometric discrepancies of mitral-LV complex between saline-injected LV and beating LV may result in incomplete MVP. Thus, we compared 3 dimensional (3D) geometry of beating heart with that during SIT at arrest.
Methods : (Figure⇓) Sonomicrometry crystals were implanted to mongrel dogs (n=7) on mitral annulus (6 pts), coaptation points of mitral leaflets (CP, 2×2 pts), tips of papillary muscles (PMs) (2 pts), and LV apex (1 pt) under cardiopulmonary bypass (CPB). 3D geometric data were acquired from arrested LV filled with saline under CPB (at SIT), and from beating heart at end-systole (at ES) after CPB.
Results : (Table) At SIT, annular height (AH) was lower and commissural width (CW) was larger than those at ES, which indicate that saddle shaped mitral annulus was more flattened at SIT. In addition, the width of middle scallop and the distance between the tips of each PMs were larger at SIT, which imply more stretched middle scallop by traction of marginal chordae. Most importantly, the distance between the tips of each PM and the CP (PM tip-CP) was constant between SIT and ES.
Conclusions : Because of the constant PM tip-CP both at SIT and ES, SIT can be informative to determine reconstructed chordal length. However, more flattened mitral annulus and over-stretched leaflets at SIT may provide inaccurate evaluation of complex MVP.