Virtual histology-intravascular ultrasound assessment of lesion coverage after angiographically-guided stent implantation in patients with ST Elevation myocardial infarction undergoing primary percutaneous coronary intervention.

An occlusion or severe stenosis (angiographic culprit lesion) of the infarct-related artery is frequently located at the site of the maximum thrombus burden, whereas the origin of the plaque rupture (the true culprit) can be situated proximal or distal to it. The aim of this study was to examine stent coverage of true culprit lesions in 20 patients who underwent primary percutaneous coronary intervention and had Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow restored in the infarct-related artery by angiographically guided direct stenting. Images of lesions were obtained using virtual histology-intravascular ultrasound before and after intervention (blinded to the operator). Plaque rupture sites were identified by intravascular ultrasound in 12 lesions (60%), 11 proximal and 1 distal to the minimum luminal area (MLA). Maximum necrotic core sites were found proximal to the MLA in 16 lesions, at the MLA in 3 lesions, and distal to the MLA in 1 lesion. Plaque rupture sites were fully covered by stents in 11 lesions. Virtual histology-intravascular ultrasound-derived thin-cap fibroatheroma longitudinal geographic misses were found in 10 lesions, 7 in the proximal reference segment and in 3 patients in the proximal and distal reference segments. In conclusion, in about 50% of patients who undergo primary percutaneous coronary intervention for ST-segment elevation myocardial infarction with optimal angiographic results, the stent does not fully cover the maximum necrotic core site related to the culprit lesion.