Abstract 15567: Global Longitudinal Strain at Rest and During Exercise Accurately Predicts Extensive Diffuse Myocardial Fibrosis at Histology and T1 Mapping in Aortic Stenosis
Introduction: LV biopsy is a reference standard for the assessment of diffuse myocardial fibrosis (DMF). Magnetic resonance imaging (MRI)-derived native T1 relaxation time provides a noninvasive assessment of DMF.
Hypothesis: We tested the hypothesis that global longitudinal strain (GLS) at rest and during exercise will predict extensive DMF at LV myocardial histology and MRI-derived T1 mapping.
Methods: The study population consisted of 54 consecutive patients (age 70.8±9.3 y, 69% males) with moderate to severe aortic stenosis (AS) (AVA <1.2 cm2) and 17 healthy controls (age 42.5±9.7 y, 47% males). AS patients underwent 2D speckle tracking strain echocardiography at baseline (n=54) and during submaximal semi-supine bicycle exercise (n=25), native T1 relaxation time assessment using the modified Look-Locker Inversion recovery sequence (MOLLI) (n=54) and LV myocardial biopsy during AVR (n=23).
Results: When compared with controls, patients with AS had significantly lower magnitude of GLS at rest (-22.5±2.0% vs. -17.9±4.4%; p<0.001) and during exercise (-27.0±1.4% vs. -20.6±6.5%; p <0.001), and longer T1 relaxation time (1197±45 vs. 1260±59ms; p <0.001). GLS at rest showed significant correlation with percentage of myocardial collagen (r=0.71; p <0.001) and T1 relaxation time (r=0.73; p <0.001). GLS magnitude lower than -15% had high accuracy (Ss=100%, Sp=88%, AUC =0.96) to identify extensive (> 30%) myocardial collagen content (Figure 1). We observed a significant correlation between the GLS during exercise and the T1 relaxation time (r=0.86; p <0.001). A total of 10 (40%) AS patients and 0 controls showed limited contractile reserve (% Δ GLS -16.5±15.5% vs. +20.9±10.4%; p<0.001). Patients with limited versus preserved contractile reserve showed significantly longer T1 time (1303±38 ms vs. 1219±47 ms, p<0.0001) suggestive of extensive DMF (Figure 2).
Conclusions: GLS both at rest and during exercise accurately predicts extensive DMF in aortic stenosis.
Author Disclosures: T. Ondrus: None. R. Kockova: None. C.D. Mirica: None. M. Kotrc: None. A. Praveckova: None. Y. Mo: None. G. Van Camp: None. M. Penicka: None.
- © 2016 by American Heart Association, Inc.