Relationship between plaque composition and no-reflow phenomenon following primary angioplasty in patients with ST-segment elevation myocardial infarction--analysis with virtual histology intravascular ultrasound.

BACKGROUND: The angiographic no-reflow phenomenon after primary percutaneous coronary intervention (PCI) carries a poor prognosis in patients with ST-segment elevation myocardial infarction (STEMI). However, the type of plaque composition that associates with the angiographic no-reflow phenomenon remains unclear.

METHODS: A total of 44 patients with STEMI were enrolled in this study. After thrombectomy with an aspiration catheter, virtual histology intravascular ultrasound (VH-IVUS) of the infarct-related vessel was performed. Patients were divided into two groups according to final thrombolysis in myocardial infarction (TIMI) flow grade at the completion of PCI procedure. Complete reperfusion group (CR-group) was defined as final TIMI flow grade 3, and no-reflow group (NR-group) was defined as final TIMI flow < or = 2. The relationship between plaque composition and angiographic no-reflow phenomenon was analyzed.

RESULTS: The angiographic no-reflow phenomenon was observed in 20 individuals. The summation of the percentage of fibrofatty+necrotic core and fibrofatty+dense calcium was significantly higher in the NR-group. Receiver-operating characteristics analysis revealed that the summation of the volume and percentage of fibrofatty+necrotic core (> 20.1 mm(3), 26.2%) and fibrofatty+dense calcium (> 20.0 mm(3), 22.6%) predict the angiographic no-flow phenomenon.

CONCLUSION: The fibrofatty-rich component with necrotic core or dense calcium derived from VH-IVUS is closely related to the angiographic no-reflow phenomenon observed in primary PCI.