P1404 Additional power of automated longitudinal strain during dobutamine stress echo for detecting inducible ischemia in left anterior descending artery stenosis
Authors: Ilardi F , Santoro C , Lembo M , Dulgheru R , Esposito R , Sorrentino R , Marchetta S , Sellitto V , Lancellotti P , Esposito G , Galderisi M 
Published: January 2020

Abstract

Background
Dobutamine stress echo (DSE) is a sensitive but subjective test of inducible ischemia. Speckle tracking allows now a quantitative assessment of regional wall motion, even during DSE.

Purpose
To investigate the feasibility and accuracy of global and regional longitudinal strain during DSE to detect significant CAD.

Methods
This is a prospective, observational study, including 88 patients undergoing DSE for suspected CAD. Thirthy-three patients with negative DSE were excluded from analysis. The remaining 50 patients (82% males, mean age 66.3 ± 8.2 years) with positive DSE underwent subsequent invasive coronary angiography (CA). Besides visual regional wall motion score index (WMSI), global longitudinal strain (GLS) and regional longitudinal strain (RLS) were determined at rest, at peak stress and at early recovery by a dedicated software (Automated Function Imaging) incorporated in a quoad-screen of the echo machine and activated by automatic quantification. Obstructive CAD was defined as &gt;70% stenosis or intermediate stenosis combined with fractional flow reserve &lt;0.80.

Results
The feasibility of DES regional longitudinal strain was 100% (n = 50/50) in the pooled population. Fifteen patients did not show coronary stenosis whereas obstructive CAD was detected in 35 patients (12 with multi-vessel disease). Among these patients, 18 patients had left anterior descending artery (LAD) stenosis, 18 left circumflex coronary artery (LCX) stenosis and 15 right coronary artery (RCA) stenosis. GLS reduction at peak stress (k = 0.253, p = 0.037) and WMSI increase at peak stress (k = 0.217, p = 0.04) showed mild but significant agreement with CA for detecting significant coronary stenosis, whereas the agreement of GLS at recovery (k=-0.087, p = 0.518) was poor. When single lesion territory was considered, GLS at peak stress (17.4 ± 5.5 vs 20.5 ± 4.4%, p = 0.034) and LAD longitudinal strain (= average of 8 myocardial segments: middle and apical posterior septum, basal, middle and apical anterior septum, basal, middle and apical anterior wall) at peak stress showed significantly lower values in the obstructed LAD regions than the territories perfused by non-obstructed coronary arteries (17.1 ± 7.6 vs 21.6 ± 5.5% p = 0.021). Conversely, in presence of significant LCX or RCA stenosis, visual regional wall motion of LCX and RCA territories were higher at peak stress (WMSI LCX = 1.80 ± 0.65 in presence of LCX stenosis vs. 1.38 ± 0.44 in absence of stenosis, p &lt; 0.01; WMSI RCA = 1.89 ± 0.52 in presence of RCA stenosis vs. 1.42 ± 0.42 in absence of stenosis, p = 0.002), but RLS at peak stress showed a trend to increase, without achieving the statistical significance (RLS RCA: p = 0.128, RLS LCX: p = 0.103).

Conclusion
AFI-based strain quantitative analysis appears to be highly feasible during DSE. It appears also to be more accurate than the visual wall motion for the detection of myocardial ischemia in presence of LAD while the accuracy is suboptimal in patients with LCX and RCA stenosis.