Angiographic no-reflow phenomenon and plaque characteristics by virtual histology intravascular ultrasound in patients with acute myocardial infarction.

Objective: This study aimed to evaluate the relationship between the occurrence of the angiographic no-reflow phenomenon in patients with acute myocardial infarction (AMI) and the preintervention plaque composition as assessed by virtual histology intravascular ultrasound (VH-IVUS).

Background: The angiographic no-reflow phenomenon is an adverse prognostic factor in patients with AMI.

Methods: We enrolled consecutive 50 patients with ST-elevation AMI was treated by primary stent implantation. All culprit lesions were imaged by VH-IVUS before stent implantation. The angiographic no-reflow phenomenon was defined as a decrease in final TIMI flow grade compared with TIMI flow grade before stent implantation.

Results: Eight of 50 patients developed angiographic no-reflow after stent implantation. Gray-scale intravascular ultrasound (IVUS) showed significantly larger external elastic membrane volume and plaque burden in the no-reflow group. VH-IVUS showed a trend toward larger percentage of fibro-fatty plaque volume in the no-reflow group than in the reflow group (23.1 +/- 3.5 vs. 17.0 +/- 1.1%, P = 0.05). The presence of "marble"-like image, mainly consisting of fibro-fatty and fibrous plaque (plaque volume of fibro-fatty + fibrous >80% and containing fibro-fatty plaque volume >10%) was associated with angiographic no-reflow (P = 0.02). Corrected TIMI frame counts of the cases with "marble"-like image were significantly larger than the cases without it (46.8 +/- 5.6 vs. 27.4 +/- 2.3, P = 0.01).

Conclusions: The culprit lesions with large plaque burden, or with "marble"-like image by VH-IVUS, are associated with the angiographic no-reflow phenomenon in patients with AMI.