[The usefulness of the echo-dipyridamole test in the early period after an uncomplicated acute myocardial infarct].

OBJECTIVES

The aim of this study was to examine the ability of Dipyridamole Echocardiography Test (DET)--performed early after an acute myocardial infarction (AMI)--to assess: a) the presence of induced ischemia and its relation with coronary artery stenoses; b) the presence of myocardial viability and the comparison with late wall motion; c) the appearance of cardiac events during hospitalization and in the following period.

METHODS

Ninety-five patients with AMI, subjected to thrombolytic therapy and without complications, underwent a DET on the 4th-5th day. All had a coronary angiography on the 8th-10th day; stenoses were deemed significative when > or = 70%. DET was carried out after drug discontinuance and following standard protocol; parietal kinesis was analyzed according to a 14 segment model. The myocardium was deemed viable when an improvement of a basal dyskinesis was noted; ischemia was considered when a new asynergy appeared or a basal dyskinesis worsened or enlarged; a wall motion score index (WMSI) was calculated. All 95 pts. had a clinical follow-up at 12 +/- 6 months (3-18); 62 pts. had a late echocardiographic examination at 6 +/- 3 months (3-15).

RESULTS

Induced ischemia appeared in 59/95 pts. (62%): in 6/14 pts. (42%) without significative stenoses, in 29/49 pts. (59%) with a single vessel disease, and in 24/32 pts. (75%) with multivessel disease. In identifying multivessel disease, DET sensibility (SE) was 75% and specificity (SP) was 95-97%. In single or no vessel disease WMSI changed from 1.42 to 1.49 (p < 0.0001); in multivessel disease WMSI changed from 1.52 to 1.69 (p < 0.0001). As regards the assessment of diseased vessel(s), DET showed little accuracy when dyskinesis appeared in the basal segments of the inferior and lateral wall or in the mid-apical segments of the anterior and lateral wall; DET properly identified the culprit vessel when dyskinesis appeared in the remaining segments. Myocardial viability was noted in 26% of dyskinetic segments. In single or no vessel disease WMSI changed from 1.41 (basal--> B) to 1.35 (viability phase--> V) and was found 1.31 at the late echocardiography (L): p < 0.0001 between B and V, and between B and L. In multivessel disease WMSI changed from 1.5 (B) to 1.47 (V) and to 1.5 (L): p < 0.05 between B and V, NS between B and L. In comparison with late echocardiography, DET SE was 70%, SP 99%, positive predictive value (PPV) 97%, negative predictive value (NPV) 86%. As regards the prognostic value about cardiac events, DET SE was 80% and NPV was 78%; about only major cardiac events, the respective values are 91% and 97%.

CONCLUSIONS

DET performed early after an AMI allows a better prognostic assessment, as it provides information about: a) the place and the severity of coronary artery stenoses; b) the presence and the extension of induced ischemia and of myocardial viability; c) the risk of subsequent cardiac events.