Feasibility analysis of longitudinal strain assessment in patients undergoing contrast and non-contrast enhanced stress echocardiography

Background Stress echocardiography (SE) is an established method for detecting myocardial ischemia based on visual assessment of wall-motion abnormalities during exercise or dobutamine stress [1,5]. To overcome the limitations of qualitative evaluation, quantitative assessment of regional contractility using deformation imaging has been proposed as an adjunct to SE [2,3]. Among strain parameters, longitudinal strain (LS), which is pathophysiologically linked to ischemia, may quantify segmental function; however, evidence regarding its applicability and the impact of ultrasound contrast agents (UCA) remains conflicting [3,6]. Purpose To evaluate the feasibility of global (GLS) and segmental longitudinal strain (SLS) during dobutamine stress echocardiography (DSE) and to assess the effect of UCA use. Methods DSE studies from routine clinical practice that fulfilled predefined quality criteria (adequate endocardial delineation irrespective of UCA use, absence of foreshortening or off-plane motion, and clear ECG signal) were included. GLS and SLS were assessed using an 18-segment left ventricular model from three apical views at baseline, low-dose DSE (20 μg/kg/min; LSE), and peak stress (PSE). Segments with inadequate tracking after three manual adjustments were excluded; GLS was considered non-feasible when >3 segments were rejected. Analyses were performed according to contrast use: contrast-enhanced (CE) versus non-contrast-enhanced (NCE). Results Of 128 DSE studies (GE E95, single experienced operator), 73 met quality criteria (29 CE; 39.7%). Baseline characteristics did not differ between CE and NCE groups. GLS was non-feasible in 10/29 CE versus 15/44 NCE studies during LSE (p=0.97) and in 11/29 versus 12/44 at PSE (p=0.34). Feasibility at LSE did not predict feasibility at PSE. Overall, 98/1314 segments were rejected at baseline (7.4%; 1.3±1 per patient). The mean number of rejected segments was similar between groups at LSE and PSE (2.8±2.3 vs 2.7±2.1, p=0.87; and 3.3±2.0 vs 3.1±2.6, p=0.74, respectively). Basal inferolateral segments were most frequently rejected, increasing from 17.8% at baseline to 35.6% at LSE and 45.2% at PSE. The mid-ventricular level and apical four-chamber view showed the highest feasibility irrespective of UCA use. Conclusions Under optimal acquisition conditions, GLS during SE is feasible in approximately two-thirds of patients. Segment rejection increases from low-dose to peak stress, most frequently affecting basal inferolateral segments, without a measurable impact of UCA use.