RESUMO
OBJECTIVE: To assess the role of myocardial contrast echocardiography (MCE) in early identification of myocardial viability in patients with residual segmental dysfunction after myocardial infarction and primary angioplasty (PA), in comparison with dobutamine stress echocardiography (DSE), using late functional recovery as gold standard. DESIGN: Prospective study for comparison of the two methods. SETTING: Hospital. PATIENTS: 17 patients (11 male, 53 +/- 11 years old) were consecutively included, with a first myocardial infarction and PA, with residual segmental akinesis or dyskinesis and good echocardiographic window. METHODS: All patients underwent: a) baseline echocardiographic study, MCE, and DSE obtained at 4.0 +/- 1.2 days after PA; b) late echocardiographic study performed at 4.4 +/- 0.8 months after PA. MCE was performed with Optison, administered as a slow infusion via a peripheral vein and a modality of real-time perfusion imaging with power pulse inversion and flash and subsequent data acquisition of triggered end-systolic images. Segmental contractility and perfusion were assessed using a 16-segment model. Perfusion assessment was qualitative (three perfusion patterns) and quantitative (ratio of maximal intensity between dysfunctional segments and contralateral normal segments). The viability criterion for MCE was defined as homogenous enhancement in 50% of wall thickness in each segment. The standard criterion for myocardial viability was defined as late functional recovery. 6. RESULTS: Viability was present in 56 (63.6%, Group 1) of dysfunctional segments and was absent in the remaining 32 (36.4%, Group 2). The sensitivity of DSE for viability was 80.0%, while specificity was 86.5%. The positive and negative predictive values were, respectively, 91.8% and 69.6%. MCE yielded a sensitivity of 96.5% and specificity of 78.1%, while positive and negative predictive values were respectively 86.2% and 94.1%. With the two methods together, the positive predictive value was 90.3% and negative was 80.0%. The intensity ratio was higher for viable segments (Group 1) in comparison with non-viable ones (Group 2; p<0.005). 7. CONCLUSIONS: This study showed a potentially valuable role for MCE in assessing viability in patients with myocardial infarction and PA. In comparison with DSE, MCE yielded a higher negative predictive value as well as a high positive predictive value. The use of both methods together is promising as a useful tool for early assessment of viability after primary angioplasty.