VALUE OF MYOCARDIAL CONTRAST ECHOCARDIOGRAPHY FOR PREDICTING LEFT VENTRICULAR REMODELING AND REGIONAL FUNCTION AT REST AND UNDER STRESS IN PATIENTS WITH ANTERIOR WALL ACUTE MYOCARDIAL INFARCTION
Authors: Caldas M.A. , Sbano J.C. , Kowatsch I. , Tsutsui J.M. , Beck L. , Nicolau J.C. , Andrade J.L. , Mathias. W. 
Published: February 2004

Background: The extent of myocardial salvage after acute myocardial infarction (AMI) treated with thrombolysis or percutaneous transluminal coronary angioplasty is variable and cannot be predicted based on either vessel patency or early regional wall motion assessment.

Aim: To evaluate the predictor value of myocardial contrast echocardiography (MCE) using intermittent second harmonic imaging, in left ventricular remodeling and regional contractile function at rest and under stress during the first 48 hour after first anterior wall AMI treated with successful thrombolysis or angioplasty.

Methods: We studied 31 patients with mean age 64 ± 12 years, 20 men. MCE was performed 34 hour, 5.5 days and 36 days after AMI, and evaluation of the change in left ventricular volumes and regional function was done in 6 months, using MCE at rest and dobutamine‐atropine stress. In order to analyze the contraction and myocardial perfusion, left ventricular wall motion score index (WMSI) and myocardial perfusion score index (MPSI) were calculated using a 16‐segment model. Patients were divided into two groups: ventricular remodeling group (RG)—20% increase in left ventricular end‐diastolic and end‐systolic volumes (19 patients) ‐ and no ventricular remodeling group (NRG) (12 patients). patients were also classified according to the number of no‐contrast opacification myocardial segments observed in the first MCE: reflow up to 2 segments and no reflow over 2 segments.

Results: In the first echocardiography, no statistical difference was observed between groups regarding left ventricular volumes and ejection fraction, but WMSI (p = 0.049), MPSI (p = 0.006) and the number of no‐contrast opacification myocardial segments (p = 0.018) were higher in RG. Left ventricular end‐diastolic and end‐systolic volumes and WMSI increased significantly (p < 0.001) in the GR from the first echo to that at 6 months follow‐up, and decreased (p < 0.001) in the NRG. Left ventricular ejection fraction decreased in the RG (p < 0.001) and increased in the NRG (p < 0.001). There was a significant increase in the MPSI in the RG between the first echo and that at 36 days follow‐up (p = 0.011). Logistic regression analysis showed that only the MPSI was an independent predictor of left ventricular remodeling (odds ratio of 1.8, p = 0.010). Twenty‐eight patients performed dobutamine stress echocardiography, of whom 15 were no reflow and 13 patients were Reflow. Only 27.8 ± 19.9% of the anterior wall myocardial segments had functional recovery or contractile reserve at 6 months follow‐up in no reflow patients, whereas, in reflow patients, 69.9 ± 31,2% of the anterior wall myocardial segments had functional recovery or contractile reserve (p < 0.001).

Conclusion: Left ventricular MPSI analyzed at first 48 h after the anterior wall AMI treated with successful thrombolysis or angioplasty is an independent predictor of left ventricular remodeling. Moreover, patients with a maximum of 2 no‐contrast opacification myocardial segments by MCE revealed a higher percentage of myocardial segments with functional recovery or contractile reserve.