Coronary flow velocity analysis during short term follow up after coronary reperfusion: use of transthoracic Doppler echocardiography to predict regional wall motion recovery in patients with acute myocardial infarction.

BACKGROUND: A recent study using a Doppler guide wire showed that coronary flow velocity measurements immediately after coronary reperfusion were useful in predicting recovery of regional left ventricular function. The value of coronary flow velocity analyses during follow up after reperfusion has not been established in the clinical setting.

OBJECTIVE: To evaluate coronary flow velocity measurements in predicting recovery of regional left ventricular function during short term follow up after acute anterior myocardial infarction, using transthoracic Doppler echocardiography (TTDE).

METHODS: 30 consecutive patients with anterior acute myocardial infarction were studied. They all underwent successful coronary angioplasty for lesions in the left anterior descending coronary artery (LAD). Using TTDE, coronary flow velocity in the LAD was recorded on days 1 and 3, and at one and two weeks after reperfusion. Regional wall motion was analysed by the wall motion score index (WMSI), calculated as an average of segmental scores in the LAD territory before reperfusion and one month after the infarction.

RESULTS: Deceleration time of diastolic flow velocity (DDT) in patients with viable myocardium (WMSI in LAD territory at one month, < 2.0) was significantly longer after recanalisation than in patients without viable myocardium (WMSI in LAD territory at one month, > 2.0): 657 (226) v 271 (117) ms on day 1, p < 0.001; 732 (219) v 373 (217) ms on day 3, p < 0.01; and 903 (107) v 577 (300) ms at one week, p < 0.01. However, the difference at two weeks (991 (75) v 795 (281) ms) was not significant. For the prediction of viable myocardium, DDT > 600 ms had a sensitivity of 78% and a specificity of 92% on day 1, and a sensitivity of 78% and a specificity of 84% on day 3. At one and two weeks, DDT > 600 ms was sensitive (100% and 100%, respectively) but less specific (46% and 26%, respectively) for predicting viable myocardium.

CONCLUSIONS: Non-invasive assessment of coronary flow velocity using TTDE within three days of successful coronary angioplasty in patients with anterior acute myocardial infarction is useful in predicting recovery of regional left ventricular function.