Author + information
- Published online February 14, 2018.
- Kenji Matsumoto, MD, PhD,
- Shoichi Ehara, MD, PhD∗ (, )
- Takao Hasegawa, MD, PhD,
- Satoshi Nishimura, MD, PhD and
- Kenei Shimada, MD, PhD
- ↵∗Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
The presence of underlying vulnerable plaques, especially thrombus, has the potential to influence arterial healing and possibly long-term outcomes in patients with angina pectoris after percutaneous coronary intervention (PCI) (1). T1-weighted imaging (T1WI) with noncontrast magnetic resonance (MR) can effectively assess coronary intraluminal thrombus through a high-intensity signal (HIS), determined by the plaque-to-myocardial signal intensity ratio (PMR) (2). We identified the optimal PMR cutoff value for predicting optical coherence tomography (OCT)–defined intraluminal thrombus and investigated the prognostic value of the target lesion HIS among patients with angina who underwent OCT-guided stent implantation.
One hundred and three patients with either stable (n = 42) or unstable (n = 61) angina, who underwent MR within 24 h before the day on which OCT-guided PCI was performed, were prospectively examined. All patients were scanned using a 1.5-T MR imager (Achieva, Philips Medical Systems, Best, the Netherlands) with a 5- or 32-element cardiac coil. Coronary target plaque images were obtained using a 3-dimensional T1WI, inversion recovery, and fat-suppressed black-blood gradient-echo sequence with navigator-gated free-breathing and electrocardiogram-gated techniques (2). After the optimal PMR cutoff value for the prediction of OCT-defined thrombus was identified, target lesions with a PMR higher than the cutoff value were classified as HISs. In addition, HISs were further divided into intrawall and intraluminal HISs based on localization by using cross-sectional T1WI (Figure 1A) (2). Major adverse cardiac and cerebrovascular events (MACCEs) were defined as the composite of cardiovascular death, nonfatal acute coronary syndrome, stroke, unplanned de novo PCI, and target lesion revascularization.
During the follow-up period (median 1,123 days), MACCEs were observed in 23 patients. PMR values (p = 0.036) and the frequency of OCT-defined thrombus (p = 0.0073) were significantly higher in patients who developed MACCEs than in those who did not. No significant differences in stent type and minimum stent area after PCI were found. Receiver-operating characteristic curve analysis showed that the optimal PMR cutoff value for OCT-derived thrombus was 1.20 (area under the curve: 0.77; p = 0.0024). According to the PMR and localization of HIS, patients were divided into 3 groups: non-HISs (n = 54), intrawall HISs (n = 24), and intraluminal HISs (n = 25) (Figure 1A). Intraluminal HISs were strongly associated with OCT-derived thrombus (non-HISs: 11%, intrawall HISs: 17%, intraluminal HISs: 76%; p < 0.001), and had the highest incidence of overall MACCEs among the 3 groups (11% vs. 29% vs. 40%; p = 0.011). The cardiovascular death rates were 0%, 4%, and 4%; the stroke rates were 0%, 4%, and 4%; the unplanned de novo PCI rates were 7%, 13%, and 4%; and target lesion revascularization rates were 4%, 8%, and 16% in the non-HIS, intrawall HIS, and intraluminal HIS groups, respectively. All 3 acute coronary syndrome events occurred in the intraluminal HISs group. The Kaplan-Meier curve for MACCEs revealed that a trend toward having MACCEs was observed in patients with intrawall HISs compared with non-HISs (p = 0.052). Further, intraluminal HISs showed a significantly higher rate of MACCEs than that shown by non-HISs (p < 0.01) (Figure 1B). Multivariate Cox regression analysis identified 3-vessel disease (hazard ratio: 4.22; 95% confidence interval: 1.39 to 12.90; p = 0.012), and the presence of intraluminal HIS at the target lesion (hazard ratio: 2.88; 95% confidence interval: 1.01 to 9.11; p = 0.049) as significant predictors of MACCEs.
Although PCI with drug-eluting stents markedly improved clinical outcomes, serious concerns about late complications remain, such as in-stent neoatherosclerosis, which is an important substrate for in-stent restenosis and late stent thrombosis (1). Intraluminal HISs may indicate that a large number of thrombi develop from plaque rupture based on the presence of vulnerable complex plaques associated with a necrotic core and intraplaque hemorrhage. The presence of large thrombus-related vulnerable lesions with intraluminal HISs may be reflected in the higher occurrence of late stent failure and may cause differences in the rate of target lesion–related events between intrawall and intraluminal HISs. In the present study, MACCEs also arose from previously untreated nontarget lesions. These results may suggest that plaque vulnerability can be considered not only a local vascular event, but also a panvascular process with the potential to destabilize atherosclerotic plaque in nonculprit lesions. Therefore, patients with vulnerable plaque characteristics should be considered “vulnerable patients” with regard to imaging modality.
This study identified thrombus-related HIS, especially intraluminal HIS, at target lesions as an independent predictor of MACCEs after PCI. These results may help to identify patients at high risk for long-term cardiovascular events.
Please note: This work was supported by JSPS KAKENHI (26461080). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
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