| The incidence and predictors of malapposition in drug-eluting stent assessed by optical coherence tomography[Background] Pathology studies had described delayed neointimal healing as the common morphologic finding in fatal cases of late and very late stent thrombosis. Several studies revealed that late stent malapposition may delay the neointimal coverage. However, the immediate stent malapposition in drug-eluting stent (DES) was seldom studied.[Objective] To assess the effects of clinical diagnosis, stents, local features of coronary artery lesions and intervention operation factors on immediate stent malapposition of DES by optical coherence tomography (OCT).[Methods] This retrospective study included78patients who accepted OCT both pre-procedure and post-procedure from June2009to June2010. Patients were divided into ST-segment elevation myocardial infarction (STEMI) group(18patients), unstable angina pectoris (UAP) group(30patients) and stable angina pectoris (SAP) group(30patients). Stent malapposition and the clinical outcome of the three groups were analyzed. Subgroup analysis compared the incidence of stent malapposition between the overlapping stent group(n=20) and the single stent group(n=20). Regression analysies assessed the effects of local features of coronary artery lesions (including: thrombus load, the degree of calcification, unstable plaque that is thin-cap fibroatheroma (TCEA), atherosclerosis, lesion length, the degree of stenosis), stents and intervention operation factors on immediate stent malapposition of DES in58cases with single DES.[Result] The percentage of stent malapposition immediately after PCI was (7.48±4.06)%(STEMI group (9.04±4.67)%vs UAP group (8.10±4.22)%vs SAP group (5.93±2.99)%, P<0.05). The percentage of stent malapposition in STEMI group was higher than in SAP group (P<0.05). There was no significant differences of the incidence of MACE among the three groups during30.73±2.82months follow-up (P>0.05). The subgroup analysis revealed that the percentage of stent malapposition was higher in the overlapping stent group than in the single stent group (11.31±5.48%vs5.91±4.37%, P=0.007). Mainly because in the overlapping stent group, the percentage of stent malapposition was much higher in overlapped segments than that in non-overlapped segments. Multivariate analysis revealed that sirolimus-eluting stent (SES)(β=4.3%, P=0.001), calcification(β=2.0%, P=0.001), thrombi(β=0.8%, P=0.019) were positively related to immediate stent malapposition. The post dilatation(β=-0.2%, P=0.004) was negatively correlated to immediate stent malapposition.(Conclusion] This study showed that the percentage of stent malapposition at immediate post-procedure in STEMI was higher than in SAP. Compared with the single stent group, the percentage of stent malapposition in the overlapping stent group was higher, especially in the overlapped segments. SES, calcification, thrombi could increase stent malapposition. Post dilatation might reduce the incidence of stent malapposition. Optical coherence tomography analysis in patients with very late stent thrombosisTBackground] Very late stent thrombosis (VLST) is a potentially life-threatening complication, but the underlying mechanisms remain unclear.[Objective] We used optical coherence tomography (OCT) to analyse23patients who presented with very late stent thrombosis (VLST) after either drug-eluting stent (DES) or bare-metal stent (BMS) implantation.[Methods] In23patients (18DES-and5BMS-treated lesions) with definite VLST, OCT images were acquired before percutaneous coronary intervention (PCI).[Result] The duration from implantation to VLST in DES group was longer than in BMS group((112.00±51.36) months vs (41.39±19.64) months, P<0.001). The neointimal hyperplasia thickness(NHT) of DES group was larger than of BMS group((0.33±0.24)μm vs (0.26±0.22) μm, P<0.001). In the overall cohort, VLST was associated with in-stent neointimal rupture in15patients (65.22%), and there was no significant difference between DES group and BMS group (55.56%vs100%, P=0.07). The site of neointimal rupture was near the minimal lumen area in13patients (56.52%). TCFA-containing neointima was observed in18patients (78.26%) and late in-stent restenosis in15patients (65.22%). Uncovered struts were observed in17(73.91%) lesions, and14of them at the site of thrombi. All BMS with VLST showed no malapposition. The proportion of uncovered struts in DES group were more than in BMS group(2.04%vs0.68%, P=0.028).8(34.78%) stented segments with uncovered struts also had neointimal rupture. Only2(8.70%) lesions had no evidence of neointimal rupture or uncovered struts. Compared with lesions without neointimal rupture, lesions with neointimal rupture showed a higher frequency of TIMI<3grade (60.00%vs.12.50%, P=0.038).[Conclusion] OCT imaging indicated that in-stent advanced neoatherosclerosis with neointimal rupture was widespread in BMS-VLST and DES-VLST, and that in DES-VLST was earlier than in BMS-VLST. Delayed neointimal healing was observed more in DES-VLST. Long-term follow-up of the neointimal coverage and stent malapposition of the overlapping drug-eluting stents by optical coherence tomography[Background] Histologic experimental studies reported that in drug-eluting stents (DES) overlapped segments impaired neointima healing in animals. On the contrary, angiographic studies suggested that overlapping DES maybe elicited neointimal hyperplasia. By far, the neointima healing in overlapping DES was seldom studied.[Objective] Using optical coherence tomography (OCT) to assess coverage and apposition of overlapping DES on long-term follow-up.[Methods] This retrospective analysis included18patients with22overlapped segments of homogeneous DES over1year after implantation. Neointimal coverage and stent apposition of overlapped segments and the corresponding nonoverlapped segments were detected by OCT.[Result] The mean follow-up duration was33.28±22.88months. A total of17,870struts were analyzed. The rate of uncovered struts and malapposed struts in overlapped segments were higher than in nonoverlapped segments((2.60±5.05)%vs(1.54±1.94)%,(0.25±0.64)%vs (0.07±0.19)%, respectively, both P<0.05).The neointimal hyperplasia thickness(NHT) in overlapped segments was less than that in nonoverlapped segments ((0.22±0.16) mm vs (0.24±0.33) mm, P<0.05). There were no differences in the proportion of late lumen area loss between overlap and nonoverlap segments ((24.45±14.40)%vs (22.64±16.50)%,(0.21±0.15) mm vs (0.23±0.32) mm, respectively, both P>0.05). In-stent restenosis was observed in6/18(33.33%) lesions and all of them were at the site of nonoverlapped segments, only one case both involved overlapped segment.[Conclusion] Compared with nonoverlap segments, the vascular healing was delayed at the site of overlapping DES segments. There were no differences in the proportion of late lumen area loss. |
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