Abstract 2688: Can Stress Echocardiography With Tissue Characterization Evaluate Noncritical Coronary Stenosis? A Validation Study Against Simultaneous Measurement of Fractional Flow Reserve
Aim of this study was to evaluate the ability of different echocardiographic modalities to detect myocardial ischemia due to non-critical coronary stenosis, compared to the fractional flow reserve (FFR) as gold standard.
Material and Methods: We investigated 22 consecutive patients presenting with stable angina, negative exercise tests and coronary 1-vessel disease with 50–75% diameter stenosis. TDE/SRI was performed at baseline and at peak hyperemia during 0.14 mg/kg/min adenosine infusion simultaneously with intracoronary FFR measurements. Angioplasty was carried out if FFR < 0.75, repeating TDE/SRI during first balloon inflation. Visual wall motion score, peak systolic values for myocardial velocity (Vs), strain rate (SRs), strain (Ss) and peak overall strain (Smax) were determined in the region of interest. Postsystolic shortening (PSS), accepted as typical marker of acute myocardial ischemia, was defined as (Smax-Ss)/Smax > 0.3, with reduced Ss < 15%.
Results: Pathologic FFR < 0.75 was found in 11 patients (Table 1⇓), who underwent angioplasty. Myocardial contractility reflected by SRs increased during hyperemia only in the patient group with FFR > 0.75 and decreased markedly during balloon inflation. Hyperemic SRs variation correlated with FFR (r = 0.5, p = 0.018) and predicted significantly pathologic FFR with an area under ROC curve of 0.86 (p <0.01). PSS was identified in 10 of 11 patients during vessel occlusion, but had a low sensitivity (2 of 11 patients with FFR < 0.75) for the more subtle changes during hyperemia.
Conclusion: Functional assessment of moderate-to-severe coronary stenosis remains a diagnostic challenge. PSS occurrence cannot serve as a reliable noninvasive alternative to FFR. However, the blunted hyperemic variation of systolic strain rate was able to predict a pathologic FFR, even in this small group of patients. Therefore, TDE/SRI emerges as a promising tool to enhance the diagnostic accuracy of adenosine stress echocardiography.