Abstract 13854: Outcome Analysis of Percutaneous Balloon Mitral Valvotomy Through Vortex Formation Time Index
BACKGROUND: Transmitral vortex assists effective transfer of blood volume, momentum and energy from left atrium to the aorta via left ventricle (LV), and minimizes the stroke work (Figure 1). Vortex formation time (VFT) is an index that quantifies the optimal conditions for vortex formation. Since accurate assessment of diastolic function in mitral stenosis with echocardiography is difficult, we hypothesized that the VFT index can be used as a measure for outcome analysis of Percutaneous Balloon Mitral Valvotomy (PBMV).
METHODS: Echocardiographic data of 36 patients with median age of 44 (33-70) with isolated MS who underwent PBMV were analyzed, retrospectively. Patients with systolic dysfunction and atrial fibrillation were excluded. VFT was computed as: [4(1- β)/π] α3 × EF, where “β” is the fraction of stroke volume contributed from atrial contraction and “α3” is a dimensionless volumetric parameter for the LV. We used a paired nonparametric method to study the change between the parameters pre- and post-PBMV.
RESULTS: 8 patients met the inclusion criteria. VFT significantly declined from a median baseline of 19.6 (7.9 - 25.5) to 7.9 (1.0 - 23.4) after PBMV (P= 0.02). A statistically significant correlation was found between VFT and deceleration time (DT) pre- (r = 0.89, p = 0.007) and post-PBMV (r = 0.83, p = 0.01; Figure 2). VFT was not associated with MVA either pre- (p = 0.08) or post-PBMV (p = 0.17) and the changes in VFT was not associated with changes in the mitral valve area (MVA) after PBMV (P = 0.47).
CONCLUSION: The good correlation between VFT and DT pre- and post- PBMV, along with the independency of VFT from MVA may suggest VFT as a useful tool for outcome analysis of PBMV.
- © 2011 by American Heart Association, Inc.