Three-dimensional MRI assessment of regional wall stress after acute myocardial infarction predicts postdischarge cardiac events.

PURPOSE: To determine the prognostic significance of systolic wall stress (SWS) after reperfused acute myocardial infarction (AMI) using MRI. MATERIALS AND METHODS: A total of 105 patients underwent MRI 7.8 +/- 4.2 days after AMI reperfusion. SWS was calculated by using a three-dimensional (3D) MRI approach to left ventricular (LV) wall thickness and to the radius of curvature. Between hospital discharge and the end of follow-up, an average of 4.1 +/- 1.7 years after AMI, 19 patients experienced a major cardiac event, including cardiac death, nonfatal reinfarction or heart failure (18.3%). RESULTS: The results were mainly driven by heart failure outcome. In univariate analysis the following factors were predictive of postdischarge major adverse cardiac events: 1) at the time of AMI: higher heart rate, previous calcium antagonist treatment, in-hospital congestive heart failure, proximal left anterior descending artery (LAD) occlusion, a lower ejection fraction, higher maximal ST segment elevation before reperfusion, and ST segment reduction lower than 50% after reperfusion; 2) MRI parameters: higher LV end-systolic volume, lower ejection fraction, higher global SWS, higher SWS in the infarcted area (SWS MI) and higher SWS in the remote myocardium (SWS remote). In the final multivariate model, only SWS MI (odds ratio [OR]: 1.62; 95% confidence interval [CI]: 1.01-2.60; P = 0.046) and SWS remote (OR: 2.17; 95% CI: 1.02-4.65; P = 0.046) were independent predictors. CONCLUSION: Regional SWS assessed by means of MRI a few days after AMI appears to be strong predictor of postdischarge cardiac events, identifying a subset of at risk patients who could qualify for more aggressive management.

Coronary blood flow assessment after successful angioplasty for acute myocardial infarction predicts the risk of long-term cardiac events.

BACKGROUND: Analysis of coronary flow velocity (CFV) in the recanalized infarct-related coronary artery (IRA) with a Doppler guidewire is useful for predicting recovery of regional left ventricular function, in-hospital complications, and survival. We postulated that the CFV pattern after IRA reperfusion for acute myocardial infarction (AMI) would predict long-term adverse cardiac events. METHODS AND RESULTS: Sixty-eight consecutive patients with a first AMI underwent CFV measurement with a Doppler guidewire after successful reopening of the IRA by coronary angioplasty. At the end of follow-up, 3.8+/-1.7 years after AMI, 44 of the 65 surviving patients (67.7%) were free of long-term cardiac events. Univariate analysis showed that the following factors were predictive of an end point combining cardiac death, recurrent MI, and congestive heart failure: hypertension, age > or =65 years, time from onset of chest pain to PTCA > or =6 hours, peak creatine kinase >4000 IU/L, ejection fraction < or =50%, proximal left anterior descending artery occlusion, resting average peak velocity < or =10 cm/s, average systolic peak velocity < or =5 cm/s, a rapid diastolic deceleration time (< or =600 ms), and early retrograde systolic flow. In the final multivariate model, only age > or =65 years (OR, 3.6; 95% CI, 1.1 to 11.8; P=0.03), time to PTCA > or =6 hours (OR, 2.9; 95% CI, 1.0 to 8.3; P=0.04), and a rapid diastolic deceleration time (OR, 5.4; 95% CI, 1.5 to 19.3; P=0.01) were independent predictors. CONCLUSIONS: The CFV pattern appears to be an accurate predictor of long-term cardiac events in patients having undergone successful reopening of the IRA after AMI, identifying a subset of at-risk patients.

3-D MRI assessment of regional left ventricular systolic wall stress in patients with reperfused MI.

The goal of this study was to assess the regional variations of end-systolic wall stress in patients with reperfused Q wave acute myocardial infarction (AMI), with the use of a three-dimensional (3-D) approach. Fifteen normal volunteers and fifty patients with reperfused AMI underwent cardiac MRI that used a short-axis fast-gradient-echo sequence. The end-systolic wall stress was calculated with the use of the Grossman formula with the radius and the wall thickness defined with a 3-D approach using the tridimensional curvature. The mean wall stress was significantly increased at each level of the short-axis plane only in patients with anterior AMI. When calculated at a regional level in patients with anterior AMI, wall stress significantly increased in anterior sector as well as normal sector. In patients with inferior AMI, wall stress significantly increased only in inferior and lateral sectors. In conclusion, the quantification of regional wall stress by cardiac MRI is better with the 3D approach than other methods for precise evaluation in patients with AMI. Despite early reperfusion, the wall stress remained high in patients with anterior AMI.