The use of contrast agents in dobutamine stress echocardiography and its influence on interobserver variability

Introduction. Dobutamine stress echocardiography is an accurate technique f or the noninvasive diagnosis of coronary artery disease. However, interobse rver variability is an important limitation of stress echocardiography. ima ge quality and echocardiographer experience have been described to influenc e interobserver agreement. Objectives. The aim of this study was to determine whether use of contrast agents during dobutamine stress echocardiography improves the agreement bet ween an experienced and a unexperienced observer, and if learning period wo uld be influenced by the use of contrast. Methods. Two blind observers interpreted all the studies: one experienced e chocardiographer (A) and one unexperienced observer (B) in this technique. The contrast agent Levovist/Levograf(R) 2.5 g was administered by two bolus (al rest and at peak stress). In all cases, second harmonic imaging and st ress digitalisation packs were used. The kappa test was used to determine i nterobserver agreement. Results. Fifty-two unselected consecutive studies in 51 patients were analy zed. Twenty-two studies were performed with contrast. The agreement between the experienced and the unexperienced observer was Kappa 0.58 and 0.52, wi th and without the use of contrast, with no statistically significant diffe rence being archived. Conclusions. The routine use of contrast provides better although not signi ficant, interobserver agreement. However, this improvement is not sufficien t to substitute specific training.