Author + information
- Adrian A. Chong,
- Kim A. Connelly,
- Jeremy M. Edwards,
- Alison L. Hokkanen,
- Chi-Ming Chow and
- Howard Leong-Poi
Undifferentiated patients with low-flow low-gradient aortic stenosis (LFLG AS: AVA<1.0cm2, LVEF<40%, mean gradient (MG)<30-40mmHg) have a poor prognosis and high surgical mortality. Identifying those with true severe AS (TS) who would most benefit from aortic valve replacement (AVR) from pseudo-severe AS (PS) remains challenging. The projected AVA (pAVA) has reasonable discriminatory value but still requires dobutamine stress echocardiography (DSE) that may be poorly tolerated in this high-risk population. We aimed to determine if the acceleration (AT) to ejection time (ET) ratio (AT:ET) is able to separate TS from PS.
A retrospective review of all DSE studies performed in a tertiary echocardiography laboratory for the assessment of LFLG AS was conducted. Standard averaged Doppler measurements for AS severity and systolic timing intervals (AT, ET and AT:ET) were recorded. Stroke work loss (SWL), valve resistance (VR) and pAVA were calculated for reference. Working definition for TS was a final AVA<1.0cm2 and/or MG>40mmHg (with AVA<1.0cm2) with/without contractile reserve (stroke volume (SV) increase >20%).
13 TS and 6 PS patients (77±8years; 26% female) were included. Resting MG (TS 26.6±5.2 vs PS 18.6±4.1mmHg, P=0.003) and peak velocity (TS 3.3±0.3 vs PS 2.9±0.3m/sec, P=0.02) were higher in TS but there were no differences in SVi, AVA or LVEF. There were significant differences in baseline AT (TS 120.4±13.8 vs PS 93.3±6.6ms, P<0.0001), AT:ET (TS 0.41±0.03 vs PS 0.32±0.03, P<0.0001) and mean:peak gradient (TS 0.60±0.04 vs PS 0.56±0.02, P<0.005). At peak-DSE, the distinction between TS and PS by AT (TS 96.6±17.0 vs PS 68.3±14.9ms, P=0.004) and AT:ET was preserved (TS 0.38±0.03 vs PS 0.30±0.03, P<0.001) and correlated with SWL (TS 19.4±4.3 vs PS 13.4±4.5%, P=0.05), VR (TS 194±42 vs PS 159±32dynes-s-cm-5, P=0.06), peak-DSE MG (TS 40.7±7.2 vs PS 25.7±7.0mmHg, P=0.002), peak-DSE AVA (TS 0.85±0.10 vs PS 1.21±0.23 cm2, P=0.01) and pAVA (TS 0.83±0.07 vs PS 1.09±0.14 cm2, P=0.005).
AT and AT:ET on resting transthoracic echocardiography are able to discriminate between TS and PS. AT:ET also appears to be a veritable flow-independent marker of AS severity.
Poster Sessions, Expo North
Saturday, March 09, 2013, 10:00 a.m.-10:45 a.m.
Session Title: Imaging: Echo – Aortic Valve Diseases
Abstract Category: 18. Imaging: Echo
Presentation Number: 1144-371
- 2013 American College of Cardiology Foundation