Abstract 10900: Application of Normal Cutoff Values for Global Longitudinal Strain in Patients with Aortic Stenosis and Normal Ejection Fraction Identifies High Valvuloarterial Impedance but Not Symptoms
Background: Prior studies have shown that global longitudinal strain (GLS) is reduced in patients with severe aortic stenosis (AS) and high valvuloarterial impedance (Zva) despite normal EF. There are no studies that have evaluated the determinants of reduced GLS and its relationship to symptom status in patients across the spectrum of AS severity. We hypothesized that applying published cutoff values for normal strain to these patients would identify those with a greater total hemodynamic load and worse symptom status.
Methods: We prospectively enrolled 133 patients scheduled for an echocardiogram to assess AS from 2008 to 2010. All subjects were in sinus rhythm with normal EF and normal wall motion at the time of study. In addition to standard measures of AS severity and diastolic function, GLS by speckle-tracking echocardiography was performed and Zva was calculated. Subjects were divided into 2 groups - normal GLS (≤-18.5%) and abnormal GLS (> -18.5%) according to the recently published normal GLS value. GLS, Zva, AVA, diastolic function, and symptom status were compared between the two groups using Pearson's correlation coefficient, student's t-test, chi-square, and Fisher's exact test where appropriate.
Results: There were 20 patients with mild AS (15%), 50 patients with moderate AS (38%), and 63 patients with severe AS (47%). Eighty-three patients (62%) had abnormal GLS (-15.1 ± 2.5%) and 50 patients (38%) had normal GLS (-20.5 ± 1.8%). Zva was significantly higher in the abnormal GLS group than the normal GLS group (4.1±1.7 mmHg/mL/m2 vs. 3.5±1.2 mmHg/mL/m2, p = 0.0051). AVA was significantly smaller in the abnormal GLS group (0.96±0.3 cm2 vs. 1.16±0.4cm2, p=0.0015). As the AS severity increased, the percentage of abnormal GLS increased (mild AS 7% abnormal GLS vs. moderate AS 40% vs. severe AS 53%, p = 0.005). Symptoms of AS were present in 36% of all subjects. There was no significant difference in the prevalence of symptoms (36% vs. 36%, p=0.987) or diastolic dysfunction (65% vs. 68%, p=0.729) between the groups.
Conclusions: In patients with a broad spectrum of AS severity and preserved EF, those with abnormal strain had significantly higher impedance and worse AS; however, abnormal strain was not associated with symptom status.
- © 2011 by American Heart Association, Inc.