Simultaneous Analysis of Two-Dimensional Strain, Coronary Flow Reserve and Wall Motion during Dipyridamole Stress Echocardiography. Comparative Outcomes.

Abstract

Background Dipyridamole stress echocardiography (DSE) is a pharmacological test accepted for the evaluation of patients with ischemic heart disease that has proved to be an ideal method that combines the visual information of wall motion with coronary flow reserve (CFR). However, the usefulness of 2D strain for the diagnosis of myocardial ischemia is still uncertain. In this sense, it seems interesting for daily practice to evaluate the results of this technique and compare them with those of other methods currently used for the evaluation of regional ischemia. Objectives To compare the results of visual analysis of wall motion and the value of CFR of the left anterior descending (LAD) coronary artery during DSE with 2D longitudinal strain in the same territory, using simultaneous 99mTc-sestamibi SPECT scan as the gold standard for the diagnosis of myocardial ischemia. Material and Methods We evaluated 41 patients (16 men; average age 68.5 years) referred for DSE. The average 2D longitudinal strain obtained of the 9 segments corresponding to the LAD coronary artery from the three apical views at rest and during stress was estimated. A drop in 2D strain value or an average increase 2) were evaluated during the peak effect of 0.84 mg/kg of dipyridamole, when intravenous 99Tc sestamibi was injected and stress SPECT images were obtained. Rest images were acquired at 24 and 48 hours. Results Three patients were excluded: one due to poor pulsed Doppler signal in the LAD and two patients presented a suboptimal ultrasound window for 2D strain. Twelve patients presented reversible perfusion defects in SPECT images (ischemic response). There was a good correlation in the four parameters evaluated in 6 patients in whom all the studies were abnormal and in 23 patients in whom all the studies were normal. In patients with normal SPECT images, 2D longitudinal strain in the territory of the LAD was –19.9% (–18, –22) at rest and –22.5% (–21, –26) during peak infusion of dipyridamole (p=0.0003). In patients with ischemia, 2D strain was –19.35% (–17, –22) at rest and –20.25% (–13, –21) during peak dipyridamole infusion (p=ns). The sensitivities and specificities obtained were: CFR, 66.7% (CI 95% 35.4-88.7) and 100%, respectively; wall motion, 50% (CI 95% 22.3-77.7) and 100%, respectively; and 2D strain, 83.3% (CI 95% 50.9-97) and 88.5% (CI 95% 68.7-97), respectively. Conclusions Simultaneous analysis of 2D strain during dipyridamole stress echocardiography proved to be a feasible quantitative method, as effective as CFR and better than the visual wall motion analysis for the diagnosis of ischemia in the territory of the LAD coronary artery.