Plaque shift and distal embolism in patients with acute myocardial infarction: a volumetric intravascular ultrasound analysis from the HORIZONS-AMI trial.

BACKGROUNDS

Vessel expansion and axial plaque redistribution or distal plaque embolization contribute to the increase in lumen dimensions after stent implantation.

METHODS AND RESULTS

Preintervention and postintervention grayscale volumetric intravascular ultrasound was used to study 43 de novo native coronary lesions treated with TAXUS or Express bare metal stents in the HORIZONS-AMI Trial. There was a decrease in lesion segment plaque + media (P + M) volume (-19.5 ± 22.2 mm(3) ) that was associated with a decrease in overall analysis segment (lesion plus 5 mm long proximal and distal reference segments) P + M volume (-17.5 ± 21.0 mm(3) ) that was greater than the shift of plaque from the lesion to the proximal and distal reference segments (1.9 ± 4.5 mm(3) , P < 0.0001). Overall analysis segment P + M volume decreased more in the angiographic thrombus (+) versus the thrombus (-) group (27.4 ± 23.4 vs. -8.9 ± 14.3 mm(3) , P = 0.003), whereas plaque shift to the reference segments showed no significant difference between the two groups (1.5 ± 5.2 vs. 2.3 ± 3.9 mm(3) , P = 0.590). Compared with the angiographic thrombus (-) group, patients in the thrombus (+) group more often developed no reflow (25% vs. 0%, P = 0.012) and had a higher preintervention CK-MB (P = 0.011), postintervention CK-MB (P < 0.001), and periprocedural (post-PCI minus pre-PCI) elevation of CK-MB (P = 0.001).

CONCLUSIONS

In acute myocardial infarction lesions, there was a marked poststenting reduction in overall plaque volume that was significantly greater in patients with angiographic thrombus than without thrombus and may have explained a greater periprocedural rise in CK-MB.