Distribuição espacial da placa vulnerável na árvore coronária: avaliação angiográfica de uma coorte consecutiva e não-selecionada de pacientes submetidos a angioplastia primária

BACKGROUND: The genesis of acute myocardial infarction (AMI) seems to be closely correlated with the rupture of vulnerable plaques. Anatomical-pathological evaluations have suggested that there is a non-homogeneous distribution of these unstable plaques along the coronary arteries. We sought to establish the "vulnerable zones" in order to obtain a risk map for AMI. METHODS: Eighty-two consecutive patients treated with primary angioplasty in a reference tertiary center, from January to September 2007, were enrolled in this analysis. Only ST elevation AMI patients with documented TIMI flow 0/1 were included. After defining the occluded segment using the Coronary Artery Surgery Study (CASS) classification, we measured the distance from the occlusion point in the culprit vessel to ostium using dedicated software (CMS-Medis). Poisson's regression model was used to determine the risk of AMI based on the distance between the occlusion and the coronary ostium. RESULTS: Mean age was 60 years and most patients were men (73.1%). LAD was the culprit vessel in most cases (46.3%). Mean reference vessel diameter was 2.8 ± 0.6 mm. For each 10 mm segment distal from the target vessel ostium, a 36.9% reduction in the chance of acute closure of the vessel was observed by the Poisson's regression model. In this cohort there was a non-homogeneous distribution of vulnerable plaques, with higher prevalence in the proximal segments of epicardic vessels. CONCLUSIONS: The findings of this in vivo analysis are in agreement with previous anatomical-pathological studies. Identification of "vulnerable zones" in the coronary tree may help to select devices for diagnostic purposes and for the prevention/ treatment of vulnerable plaques.