Abstract 10412: MRI-Based Multi-Parametric Strain Analysis Predicts Contractile Recovery After Aortic Valve Replacement for Aortic Insufficiency Better Than Echo Ejection Fraction
Reductions in echo ejection fraction (EF) currently dictate referral for aortic valve replacement (AVR) in asymptomatic aortic insufficiency (AI) patients. This surgical referral threshold may be inadequate since postoperative impairment of LV contractile function continues to occur. We hypothesize that postoperative improvement in LV function can be better predicted using MRI-based multi-parametric strain analysis. In 11 AI patients with LV impairment, cardiac MRI tagged images before AVR and 19.1±11.9 months afterward were subjected to multi-parametric strain analysis (3 strain parameters), which relates patient-specific strain to a normal human strain database (n=60). For each of 72 LV regions, a multi-parametric strain Z-score (MSZ) was calculated, which is a measure of normalized contractile injury as it reflects standard deviation from the normal average of that region. For each AI patient, the average MSZ across the 72 regions, as well as the echo EF, were acquired before AVR. Linear regression was used to evaluate both these measures as predictors for postoperative improvement. The outcome variable was the percentage of preoperatively injured regions that markedly improved following AVR. The average MSZ was shown to accurately predict the percentage of injured regions that improve after AVR (R²=.75, p=.001). The higher the average MSZ (indicating more injury), the lower the percentage of impaired regions expected to improve after AVR. Current clinical standard echo EF is not a significant predictor of recovery of injured regions (R²=.32, p=.088). MRI-based multi-parametric strain analysis more accurately predicts regional contractile recovery following AVR for AI than echo EF. LV models of representative AI patient. Expected improvement for this patient: b0+b1(preoperative average MSZ) = .93+(-.57)(1.2) = 25% of impaired regions expected to improve. Actual improvement: 13 of 43 impaired regions improved = 30%.
- © 2011 by American Heart Association, Inc.