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Paradoxical “low–flow, low–gradient” aortic stenosis (AS) despite normal left ventricular ejection fraction (LVEF) was classically described in severe AS. We aim to explore the prevalence of the low–flow (LF) phenomenon in patients with mild, moderate and severe AS.
We studied 1695 consecutive patients with AS with preserved LVEF (≥50%). Low–flow was defined as a stroke volume index of ≤35 mL.m–2. Mild AS was defined as indexed aortic valve area (AVAI) >0.9 cm2.m–2, moderate AS as AVAI of 0.6–0.9 cm2.m–2 and severe AS as AVAI of <0.6 cm2.m–2.
We found that 610 (36%) and 1085 patients had LF and normal–flow (NF) AS respectively. The mean age (73±14 vs. 71±14 yrs, p<0.001) and proportion of females (59 vs. 54%, p=0.039) were higher in the LF group. LF patients had a lower LVEF (63±7 vs. 64±6%, p=0.015), lower mean transaortic pressure gradient (18±16 vs. 21±17 mmHg, p=0.003), lower indexed left–ventricular end–diastolic volume (40±18 vs. 72±18 mL.m–2, p<0.001) and higher valvulo–arterial impedance (5.9±2.1 vs. 3.6±1.0 mmHg.mL–1.m–2, p<0.001). The prevalence of the low–flow phenomenon was higher in the severe compared to the moderate and mild AS groups (40% vs. 37% vs. 31%, p=0.022). The table shows echocardiographic parameters of AS patients grouped by severity and flow.
While ‘low–flow’ has been described primarily in patients with severe AS, there remains a substantial portion of patients with mild and moderate AS with this phenomenon. More studies are warranted.
Poster Sessions, Expo North
Saturday, March 09, 2013, 10:00 a.m.–10:45 a.m.
Session Title: Valvular Heart Disease: Clinical I – Aortic Stenosis
Abstract Category: 31. Valvular Heart Disease: Clinical
Presentation Number: 1113–90
- 2013 American College of Cardiology Foundation