Background and aim: The study was set out to assess feasibility and diagnostic value of the echocardiographic quantitative analysis of the resting regional systolic function (i.e. strain and strain rate) with use of the speckle tracking (2D strain) for myocardial viability assessment in patients with acute myocardial infarction (MI) treated with primary angioplasty. The reference method was the late enhancement magnetic resonance imaging (LE MRI).
Methods: The study group consisted of 40 patients (29 men, mean age 61 ± 9 years) in whom resting echocardiographic examination was performed 7-10 days after MI with peak systolic longitudinal strain (STS) and systolic longitudinal strain rate (SLSR) measurement by 2D strain technique on external workstation (EchoPac 6.1.0., GE Vingmed Ultrasound). Within 72 h LE MRI was performed in all patients, with visual assessment of late enhancement in all segments of the left ventricle. Viability of a segment was assessed based on two distinct, frequently adopted criteria: LE extent ≤ 50% or ≤ 75% of the wall thickness.
Results: Due to suboptimal image quality 70 (10.9%) of the segments were excluded from 2D strain analysis. In the analysis of akinetic and dyskinetic segments, SLS and SLSR measurements with 2D strain technique had good discrimination value for viability defined as LE extent of ≤ 75% by MRI (area under the ROC curve 0.715 and 0.705, respectively; diagnostic accuracy of the criterion SLS ≤ -7.61% was 72.8%; diagnostic accuracy of the criterion SLSR ≤ -0.79/s was 64.9%). However, when the ≤ 50% viability criterion by LE MRI was used, only SLS measurement could be used for viability assessment, with sufficient diagnostic value (area under the ROC curve 0.620; diagnostic accuracy of the criterion SLS ≤ -9.77% was 57%). In the analysis of all segments, including hypokinetic and normokinetic segments, SLS and SLSR measurements did not provide additional information, beyond that of the visual viability analysis.
Conclusions: Resting quantitative echocardiographic analysis of myocardial function seems to be a promising tool for myocardial viability assessment. There is a trend towards greater diagnostic value of SLS than SLSR measurements.