Abstract 1972: The Relationship between Coronary Plaque Characteristics and Small Embolic Particles During Coronary Stent Implantation
Backgrounds: Small embolic particles during coronary intervention could be detected as high intensity transient signals (HITS) using a Doppler guide wire. The relationship between baseline plaque characteristics and HITS is unknown.
Purpose: The aim of this study was to clarify the relationship between plaque characteristics assessed by Virtual-Histology Intravascular Ultrasound (VH-IVUS) before intervention and small embolic particles detected as HITS during coronary stent implantation.
Methods: Twenty-seven contiguous pts (21 males, 6 females, age 71 ± 7 yo) admitted for coronary stent implantation because of angina pectoris were included in this study. VH-IVUS examination was performed before intervention, and during a stent implantation, a waveform of coronary flow velocity signal was monitored continuously and the numbers of HITS were counted after balloon deflation. Coronary flow velocity reserve (CFVR) measurement was repeated using a Doppler guide wire before and after stenting.
Results: The mean numbers of detected HITS were 8.2 ± 6.7. According to the HITS count, pts were divided into 2 groups; group A: HITS </= 8 (n = 16), group B: HITS > 9 (n = 11). Plaque characteristics by VH-IVUS (fibrous: FI, fibrofatty: FF, dense calcium: DC, necrotic core: NC) were compared between these 2 groups. DC and NC were significantly larger in group B than in group A (DC; A: 0.08 ± 0.09 vs B: 0.44 ± 0.56 mm2, p = 0.016; NC; A: 0.5 ± 0.4 vs B: 1.2 ± 0.6 mm2, p = 0.003). Although there was no difference in CFVR before intervention, CFVR after intervention were significantly lower in group B than group A (A: 2.5 ± 1.0 vs B: 1.7 ± 0.7, p = 0.03). There was a weak but significant correlation between the numbers of HITS and NC area identified before intervention ( r = 0.489, p = 0.018).
Conclusions: DC and NC by VH-IVUS before intervention may be related to small embolic particles resulting in poorer recovery of CFVR even after successful coronary stent implantation.