Abstract 16275: Indexed Left Ventricular Mass Measured by Cardiovascular Magnetic Resonance Independently Predicts Mortality Following Transcatheter Aortic Valve Implantation
Background: Cardiovascular Magnetic Resonance (CMR) provides important structural information in patients being considered for Transcatheter Aortic Valve Implantation (TAVI). However, the relationship between CMR measurements of ventricular function and outcomes after TAVI has not previously been investigated.
Methods: 264 patients with severe aortic stenosis attending a tertiary centre underwent CMR using a 1.5T scanner and a standardized protocol. Steady-state free precession sequences were used for aortic valve planimetry and to assess ventricular volumes and mass. Areas of gadolinium enhancement were assessed after injection of 0.1 mmol/kg of gadolinium contrast agent. Semi-automated image analysis was performed by two specialist reviewers blinded to patient treatment. Patient follow-up was obtained from the Office of National Statistics national mortality database; mean follow-up time was 20 months (range 1-64 months).
Results: 174 of 264 patients scanned underwent TAVI and 90 were treated medically. Baseline characteristics were similar between the TAVI and medical groups: mean age 78.2 vs. 78.0 years (p=0.83), mean LV ejection fraction 59.8% vs. 58.6% (p=0.89), mean indexed LV mass 54.5g/m2 vs. 54.7g/m2 (p=0.53). On univariate analyses, TAVI (Hazard ratio [HR] 0.36, p<0.01), peak aortic flow velocity (HR=0.66, p=0.04), indexed left ventricular (LV) mass >65g/m2 (HR 2.43, p<0.01), and LV stroke volume (HR 0.99, p<0.01) correlated with all-cause mortality. On multivariate analysis, only TAVI (HR 0.35, p<0.01) and LV mass index >65g/m2 (HR 1.8, p<0.01) correlated independently with mortality. Cox regression analysis showed that the reduction in mortality risk following TAVI increased according to baseline LV mass index (Figure, p<0.01).
Conclusions: Indexed left ventricular mass on pre-procedural MRI is an independent predictor of mortality following TAVI. The relative benefit of TAVI was found to increase as indexed LV mass increased.
- © 2013 by American Heart Association, Inc.