Intravenous contrast echocardiography after myocardial infarction: relationship among residual myocardial perfusion, contractile reserve and long-term remodelling

Abstract

Previous studies have shown the potential role played by intracoronary myocardial contrast echocardiography (MCE) in predicting long-term remodelling and function after myocardial infarction (MI). Scanty data, however, are available on the role of intravenous MCE in this regard. The aim of this study was to assess the role of residual myocardial blood volume in the asynergic region in modulating ventricular volume changes over time post-MI. Thirty-two consecutive patients with anterior MI were studied predischarge using low-dose dobutamine echocardiography (Dob) and intravenous triggered MCE. Videointensity plots were generated from the apical approach and fitted exponentially. Volumes were assessed at baseline, during Dob and at 8 months. Baseline volumes, which appeared related to the extent of the asynergic region (P < 0.01) but showed no relation with videointensity in that area, did not change at follow-up, although Dob had elicited significant contractile reserve. However, videointensity in the asynergic region showed a significant interaction (P = 0.044) with the change in diastolic volume over time, with patients with the highest videointensity reverting remodelling (n = 11, from 69 +/- 16 to 65 +/- 16 ml/m) as compared with the remaining population (n = 21, from 68 +/- 16 to 73 +/- 21 ml/m). This was not seen when Dob-derived parameters were used. Multivariate analysis ranked videointensity second (P = 0.066), after baseline stroke volume (P = 0.005), in predicting changes in volumes over time. Unlike inotropic reserve, residual myocardial blood volume in the dysfunctioning muscle, as assessed by predischarge quantitative intravenous MCE, has the potential to modulate remodelling in patients who suffered an anterior MI.