OBSERVER BIAS IN THE INTERPRETATION OF DOBUTAMINE STRESS ECHOCARDIOGRAPHY

Background and hypothesis: Blinded image analysis is typically utilize d in published studies evaluating the accuracy of dobutamine stress ec hocardiography (DSE). However, in clinical settings, practical conside rations may limit the use of blinded interpretations and thus the pote ntial for observer bias arises. This study evaluated the relationships between clinical and blinded interpretations of DSE. Methods: Wall mo tion analysis from clinical and blinded DSE interpretations were compa red and factors associated with their concordance were investigated in 115 consecutive patients with known or suspected coronary artery dise ase. Results: Clinical and blinded interpretations agreed on the prese nce or absence of inducible ischemia in 102 of 115 cases (88.7%; kappa = 0.76, p < 0.00001). In studies in which the clinical and blinded in terpretations were in agreement, there was greater ST-segment depressi on (STD) in echocardiographically positive compared with negative stud ies (mean STD 0.73 +/- 0.65 vs. 0.42 +/- 0.67 mm; p = 0.008). In contr ast, studies in which there was disagreement had significantly less ST -seg ment changes (mean STD 0.19 +/- 0.56 mm; p = 0.012) despite compa rable results an blinded wall motion analysis. Multiple logistic regre ssion for factors related to the results of clinical and blinded wall motion analysis disclosed that angina pectoris and ST-segment changes were related to clinical interpretations, whereas only angina pectoris was related to the findings on blinded analysis. Conclusions: Clinica l interpretations of echocardiographic images during DSE overall demon strate good agreement with the results of blinded analysis. Ancillary testing data may influence the analysis of wall motion abnormalities, and thus the potential for observer bias exists unless these interpret ations are performed blinded to other clinical data.