Abstract 12789: Outcome of Patients With Low Flow Aortic Stenosis and Preserved LV Ejection Fraction After Aortic Valve Replacement
Background: It has been reported that a substantial proportion of patients with severe aortic stenosis (AS) may have a low flow, and thus often a low gradient despite a preserved LV ejection fraction (LVEF). This paradoxical low flow (PLF) AS pattern may yield to underestimation of AS severity and inappropriate delay of AVR. The aim of this study was to compare the outcome of patients with PLF AS versus that of patients with normal flow (NF) AS following AVR.
Methods and Results: 318 patients with severe AS and normal LVEF (>50%) underwent isolated AVR. Among these patients 99 (31%) were in PLF as defined by stroke volume indexed to a 2.7 power of height (SVi) <22ml/m2.7. Compared to patients with NF, those with PLF had faster heart rate (72 vs. 66 batt/min; p<0.0001), smaller LV end diastolic volume (90±24 vs 104±29 ml; p<0.0001), higher relative wall thickness ratio (0.56±0.14 vs. 0.52±0.10; p<0.0001), lower LVEF (63±8 vs. 66±8% p<0.0001), smaller aortic valve area (0.68±0.35 vs. 0.80±0.34 cm2; p=0.0005), lower mean gradient (40±15 vs. 48±12 mmHg; p=0.01), and higher valvulo-arterial impedance (9.3±2.0 vs. 6.5±1.2; p<0.0001). Thirty-day mortality was higher (p=0.01) in the PLF group compared to NF group (8.1 vs. 1.8%). At 5 years post AVR, overall survival was 67% in PLF group compared to 72% in NF group (p=0.05). After adjustment for age, gender, diabetes, hypertension, chronic kidney failure and coronary artery disease and aortic valve area, patients with PLF had a 1.78 fold increase in mortality risk compared to patients with NF (p=0.04).
Conclusion: Patients with paradoxical low flow AS have higher operative mortality and worse late survival following AVR. These findings lend support to the argument that patients with PLF AS are generally at a more advanced stage of the disease. Proper identification of this disease pattern is essential to avoid any inappropriate delay in the performance of AVR.
- © 2011 by American Heart Association, Inc.