Background: Myocardial contrast echocardiography and dobutamine echocardiography have recently emerged as potentially useful clinical tools to detect reversible myocardial dysfunction. However, the relative accuracy of these two techniques in predicting regional wall motion improvement after coronary interventions is still unclear. The aim of the present study was to compare their diagnostic value in predicting functional recovery after coronary revascularization in patients with recent acute myocardial infarction.
Methods and results: Twenty-four patients with acute myocardial infarction underwent myocardial contrast echocardiography and dobutamine echocardiography within 2 weeks of hospital admission. Infarct zone contrast score and wall motion score indexes were derived in each patient. Infarct-related artery revascularization was performed before hospital discharge in all selected patients. Resting echocardiography was repeated 3 months after revascularization, and regional function recovery was analysed. The degree of wall motion score improvement at 3-month follow-up and the percentage of positive responses to dobutamine echo were greater (P < 0.001 and P < 0.002, respectively) in patients with a higher baseline contrast score (> or = 0.50). Conversely, no significant changes were observed either during dobutamine echo or after revascularization in the group of patients without residual perfusion within the infarct area. Diagnostic agreement between both techniques in predicting reversible dysfunction was high (81% of segments). The sensitivity and negative predictive value in predicting functional outcome were 100% (95% confidence interval [CI], 87% to 100%) and 100% (95% CI, 93% to 100%) by contrast echo, and 85% (95% CI, 66% to 96%) and 93% (95% CI, 84% to 98%) by dobutamine echo. The specificity and positive predictive value were 90% (95% CI, 80% to 96%) and 81% (95% CI, 64% to 93%) by contrast echo, and 88% (95% CI, 78% to 95%) and 76% (95% CI, 58% to 90%) by dobutamine echo. The combination of myocardial contrast and dobutamine echocardiography positive responses improved specificity and positive predictive value in detecting functional recovery after revascularization to 100% (95% CI, 94% to 100%) and 100% (95% CI, 85% to 100%), respectively. However, the sensitivity and negative predictive value slightly decreased with the use of both methods (85% [95% CI, 66% to 96%)] and (93%[95% CI, 85% to 98%)], respectively.
Conclusions: In patients with recent myocardial infarction, reversible dysfunction after coronary revascularization and the response to dobutamine infusion are strictly dependent on microvascular integrity. However, microvascular perfusion does not always imply functional recovery after coronary revascularization. The integration with dobutamine echo results seems particularly helpful to further improve myocardial contrast echo specificity and positive predictive values.