Flow-Gradient Patterns in Severe Aortic Stenosis with Preserved Ejection Fraction: Clinical Characteristics and Predictors of Survival
Background—Among patients with severe aortic stenosis (AS) and preserved ejection fraction (EF), those with low-gradient and reduced stroke volume may have an adverse prognosis. We investigated the prognostic impact of stroke volume using the recently proposed flow-gradient classification.
Methods and Results—We examined 1,704 consecutive patients with severe AS (aortic valve area <1.0 cm2) and preserved EF (≥50%) using 2-D and Doppler echocardiography. Patients were stratified by stroke volume index (<35 ml/m2 (LF) vs. ≥35 ml/m2 (NF)) and aortic gradient (<40 mmHg (LG) vs. ≥40 mmHg or (HG)) into 4 groups (NF/HG, NF/LG, LF/HG, LF/LG). NF/LG (n=352, 21%), was associated with favorable survival with medical management (2 year estimate 82% vs. 67% in NF/HG, p<0.0001). LF/LG severe AS (n=53, 3%), was characterized by lower EF, more prevalent atrial fibrillation and heart failure, reduced arterial compliance, and reduced survival (2 year estimate 60% vs. 82% in NF/HG, p<0.001). By multivariable analysis, LF/LG pattern was the strongest predictor of mortality (HR 3.26 (1.71, 6.22) p<0.001 vs. NF/LG). Aortic valve replacement (AVR) was associated with a 69% mortality reduction (HR 0.31 (0.25, 0.39) p<0.0001) in LF/LG and NF/HG, with no survival benefit associated with AVR in NF/LG and LF/HG.
Conclusions—NF/LG severe AS with preserved EF exhibits favorable survival with medical management and impact of AVR on survival was neutral. LF/LG severe AS is characterized by a high prevalence of atrial fibrillation, heart failure and reduced survival, and AVR was associated with improved survival. These findings have implications for evaluation of AS severity and subsequent management.
- Received May 8, 2013.
- Revision received August 12, 2013.
- Accepted August 15, 2013.