Abstract 1723: The Impact of Plaque Characterization Assessed by Intravascular Ultrasound on Myocardial Perfusion After Stent Implantation in Patients With ST-segment Elevation Myocardial Infarction
Background: Previous studies have described that inadequate tissue perfusion after primary angioplasty in patients with ST-elevation myocardial infarction (STEMI) is associated with early and late adverse cardiac events. The aim of this study was to evaluate whether baseline plaque characterization affects tissue perfusion after stent implantation in patients STEMI using intravascular ultrasound (IVUS).
Methods: We analyzed consecutive 205 patients with a first STEMI who underwent primary angioplasty with pre- and post-intervention IVUS. Maximum ST-segment elevation before angioplasty was compared with ST-segment levels 60 minutes after angioplasty in the most abnormal single lead of the standard 12-leads electrocardiogram for the assessment of myocardial perfusion. Percent ST-segment resolution (STR) was calculated from admission and post-angioplasty electrocardiogram and categorized as complete (>70%), partial (30 to 70%), and absent (<30%). Qualitative and quantitative IVUS analyses were performed using standard methods. Atheroma with deep ultrasonic attenuation (UA) was IVUS finding with backward signal attenuation>180° behind plaque without dense calcium (<30°). Percent stent expansion was calculated as minimum stent/reference lumen area.
Results: One-hundred patients had complete, 67 had partial, and 38 had absent STR. The incidences of in-hospital death and heart failure were significantly higher in absent STR patients than in the others (p=0.01, and p=0.003). IVUS data was shown in the Table⇓. Multivariate analysis showed that presence of UA and deep calcium predicted absent STR (p<0.001 and p=0.009).
Conclusions: The presence of UA and deep calcium is related to higher incidence of impaired myocardial perfusion, and as a result higher incidence of in-hospital major adverse cardiac events following primary angioplasty in STEMI patients. The use of distal protection device should be considered for these selective lesions.