| Partâ… Experimental Study on the Role of Stent in Treatment of Intracranial Aneurysm[Objective] Through vascular imaging follow- up and histopathologic detection on aneurysm model treated with endovascular stent, we evaluate the long-term healing effects of aneurysmal necks by endovascular stent, and the influence on the branch vessel covered by stent.[Methods] 1. We treated 4 bilateral carotid model aneurysms in two dogs with the methods of stent-assisted coiling and merely coiling. Neuroform self-expanding stents were used in the treatment. The coils of Matrix and GDC were used in each dog respectively. The 12-month follow-up angiography was hold for both dogs. Then the dog treated with GDC was sacrificed. The residual dog was given an angiography follow-up 30 months after the treatment. The immediate and follow-up angiography of the embolisation was reviewed. The pathologic and immunohistochemistry evaluation, as well as scanning and transmission electron microscopy assessment were taken to evaluate and compare the long-term healing effect of stent-assisted coiling and pure coiling on the wide-neck aneurysm. More attention was focused specially on the neointima covering the orifice of aneurysm.2. The implantation of BX balloon-expanding stent in the external carotid artery of three dogs was accomplished, each covering a side branch. One Neuroform self-expanding stent was implanted in the common carotid artery of another dog. The angiography was hold immediately after planting and for the follow-up at the 1st, 3rd, 12th months for review. The pathologic and immuno-histochemistry examination and associated scanning and transmission electron microscopy detection were reviewed. The homodynamic stenos is or occlusion at the debouchments of the branch vessel were concerned as well as the proliferating status of neointima covering the stent meshes.[Results] 1. All the model aneurysms had been angiographic total occlusion, and all the aneurysms were completely nonvisaulized, without any deformation of coils, at 12-month and 30-month follow-up angiography. The aneurysms merely embolised by coils couldn't cover the whole aneurysm neck, some of the loops protruded into the parent artery, and the tissue membrane was uneven and undulate. The coils and stent stick and press each other tightly to form an even grid covering on the neck of aneurysm. Pathologic examination showed a layer of neointima covering orifice of aneurysmal neck, while the one covering the stent is more tight and even. The endothelial cells at aneurysmal neck were at maturation stage and no neoformative endothelial cell were found through the transmission electron microscope and pathologic examination. 2. the branch of external carotid artery covered by stent could maintain patent, and there was mild stenosis at the debouchement of the branch vessel covered by stent, however, it didn't influence the bloodstream of the branch vessel. There is obvious tunica intima hyperplasia while no stenosis in the stent. The grid of the stent was covered by tunica intima with compacted endothelial cells. There was no intra-stent thrombus formed after the antiplatelet drug stopped at the 6th month after the operation.[Conclusions] Endovascular stent can promote the pykno-embolisation and tunica intima covering of the carotid artery aneurysm model in dogs, and is beneficial to the anatomic healing of artery aneurysm in the long term. It is secure to plant stents into the non-sclerotheromatic vessel, and there is no stenosis happened by tunica intima hyperplasia in the vessel contained stent, which also don't cause obstruction of branch vessel in a long-term follow up.Partâ…¡Clinical study: Treatment of Cerebral Wide-necked Aneurysm with Endovascular Stent[Objective] Retrospectively analyze the case history of cerebral aneurysm treated with endovascular stenting in our hospital, and we evaluate the safety and efficacy of this treatment.[Methods] Collecting 153 cases (totally 155 aneurysms) buffering cerebral aneurysms treated with endovascular stenting from the Oct. 2000 to the Oct. 2005. A summary analysis of the characteristics of history, imaging characteristics and conclusion of complications happened in the procedure, the results of post-operation imaging examination immediately after the procedure, as well as the functional conditions when the patient was discharged. We made a statistic analysis of complications happened in follow-up, the neuronal status and other prognosis. We observe the occlusion and recurrence of cerebral aneurysm with short-term and long-term imaging follow-ups. We reviewed the imaging results evaluating the patency of the stented arteries, involved branches and the condition of tunica intima covering on the aneurysm neck.[Results] All the stenting for cerebral aneurysms were technically successful, 20 cases of which were merely stented, and 135 cases of which were treated with stent-assisted coiling. Ninety-four of patients were treated with balloon-expanding stent, and 61 of them with self-expanding stent.1. The safety of stenting for cerebral aneurysm. Four patients (2.61%) suffered technical complications within perioperative period. One of them suffered rupture of recurrent aneurysm owing to placement of stenting. Another suffered in-stent thrombus, one was stent tumbling, one was then releasing well; one suffered permanent neuro-dysfunction with 0.65% of disability, and no death. One complication (0.65%) related to stent was pyknoepilepsy caused by cerebral ischemia after the operation.All of the 153-stented arteries were unobstructed beside one of them collapsed and caused patent artery occlusion. 150 cases could see the branch vessels (diameter 0.2-1.5mm, average 1.1mm) covered by stent through the imaging examination. 3 branch vessels could be seen bloodstream stepping down, and others were unobstructed.2. The imaging therapeutic effect of treating cerebral aneurysm with endovascular stent105 of 135 (77.8%) cerebral aneurysm cases were completely embolised by stent together with coils; 12 of them had residual at the corner of aneurysm, 18 of them were partly embolised. And 20 patients were treated by solely stenting. 83.3%of patients buffering tiny aneurysms had been totally embolised; 84.3%of patients buffering small aneurysm, and 45.5% of large aneurysm totally embolised. The total embolisation rate is 77.8% in the self-expanding stent group.2.2 The imaging results of short-term follow-ups2.2.1 the influence of the stent on aneurysm98 cases were follow-upped within an average period of 5.5 months (1-12 months). Of the 83 cerebral aneurysms embolised with endovascular stent, 67(80.7%) of which reached total embolisation, 16 of which were partially embolised, including 10 aneurysm shrinking, 4 aneurysm stable, and 2 recurrent (2.4%, died). 15 aneurysm treated with merely endovascular stent, we found 2 of them totally embolised, 9 of them were shrinking, and 4 of them stable in imaging.The effect of aneurysm size on the embolisation ratio20 of 21 cases (95.2%) of tiny cerebral aneurysm treated with stent together with coils were completely nonvisaulized by imaging follow-up; 2 out of 15 cases of cerebral aneurysm treated with stent only were completely nonvisaulized by imaging review, 9 were shrinking, and 4 were stable. 37 of 45 cases (82.2%) of small cerebral aneurysm were completely nonvisaulized by imaging review; 3 out of 11 per-embolisation aneurysm were completely nonvisaulized, 6 were shrinking, 1 was recurred, and 1 stable by imaging review. 10 of 17 cases(58.8%) of large cerebral aneurysm were completely nonvisaulized; 1 out of 8 embolisation-embolisation aneurysm were completely nonvisaulized, 3 were shrinking, 3 were stable, and 1 was recurrent.The effect of stent type on the embolisation ratio30 of 36 cases (83.3%) of cerebral aneurysm treated with self-expanding stent together with coils were completely nonvisaulized by imaging review. 28 cases of completely embolised cerebral aneurysm were completely nonvisaulized by imaging review; 2 out of 8 cases of partially embolised cerebral aneurysm were completely nonvisaulized, 4 were shrinking, 2 were stable by imaging review; 2 out of 10 cases of cerebral aneurysm treated with stent only were completely nonvisaulized, 5 were shrinking and 3 were stable by imaging review.37 of 47 cases (78.7%) of cerebral aneurysm treated with balloon-expanding stent assisting embolisation were completely nonvisaulized by imaging review. 32 of completely embolised aneurysm were completely nonvisaulized; 5 out of 15 partially embolised aneurysm were completely nonvisaulized, 6were shrinking, 2 were stable, and 2 recurred (4.26%). 4 of 5 cases of cerebral aneurysm treated with stent only were shrinking and 1 was stable by imaging review.2.2.2 the influence of stent implanting on the parent artery The effect of stent on the new tunica intimaWithin the 83 cases of short-term review, 67 (80.7%) cerebral aneurysm were completely nonvisaulized, 26(31.3%) could seen tunica intima covering on the aneurysm neck. Within the 23 cases of partially embolised cerebral aneurysm, 2 tiny aneurysm were covered by tunica intima on the aneurysm neck; 1 of the 15 cases of cerebral aneurysm treated with stents only was covered by tunica intima on the aneurysm neck The completely embolised cerebral aneurysm were more inclined to have tunica intima covering on the aneurysm neck, and the ratio was 40%; the covering rate of tiny aneurysm is 38.9%, which was higher than that of small and large aneurysm; the covering rate of balloon-expanding stents was 36.5%, and that of self-expanding stents was 17.4%. 16 cases of aneurysm were covered by tunica intima with an average period of 4.56 months (3-6 months), and 11 cases of aneurysm were covered by tunica intima with an average period of 9.76months(6-12 months).The effect of stent on the parent artery98 parent artery were reviewed by imaging method with an average period of 5.5 months (1-12 moths) after the operation, including 52 of them carrying balloon-expanding stents and 46 with self-expanding stents. 2 cases of self-expanding stents happened in-stent stenosis, while the other 96 vessels were unobstructed. 23 of 52(44.2%) vessels carrying balloon-expanding stents were obviously covered by tunica intima, and 13 of 46(28.3%) vessels carrying self-expanding stents were obviously covered by tunica intima.The effect of stent on the branch arteryNone of the branch vessels were obstructed by the imaging review for an average period of 5.4 months (1-11 months) postoperatively. While, 6 vessels had stenosis with slow bloodstream at the distal end.2.3 The results of long-term follow-up2.3.1 the influence of implanted stent on the aneurysm 53 of 68 cases (77.9%) of aneurysm treated with stent-assisting embolisation with an average review period of 34.3 months (12-60months) postoperatively were completely nonvisaulized by imaging examination; 11 cases were shrinking, 3 were stable and 1 recurred (1.47%). 46 of 47 cases of complete embolisation were completely nonvisaulized, and 1 recurred by imaging examination; 7 of 21 cases of partial embolisation were completely nonvisaulized, 11 recurred, and 3 were stable by imaging examination. 4 of 12 cases of aneurysm treated with stents only were completely nonvisaulized, 6 shrinking, and 2 stable by imaging examination.The effect of aneurysm size on the long-term obstruction15 of 16 cases (93.8%) of treating tiny aneurysm with stents assisting embolisation were complete nonvisaulization by imaging review, 1 was shrinking and no recurrence. 4 of 12 cases of aneurysm treated with stent only were complete nonvisaulization by imaging review, 6 were shrinking and 2 were stable. 35 of 41(85.4%) small aneurysm were complete nonvisaulization by imaging review, 5 were shrinking, 1 was stable and no recurrence. 3 out of 11(27.3%) large aneurysm were complete nonvisaulization by imaging review, 5 were shrinking and 2 were stable, as well as 1 was recurred(9.1%).The effect of stent types on the long-term artery obstruction22 of 31 cases (70.9%) of aneurysm treated with self-expanding stents assisting embolisation were completely nonvisaulized by long-term imaging review. 3 of 12 partially embolised aneurysm were completely nonvisaulized, 7 were shrinking and 2 were stable. 2 of 8 aneurysm treated with stent only were completely nonvisaulized, 4 shrinking and 2 stable.31 of 37 cases (83.8%) of aneurysm treated with balloon-expanding stents assisting embolisation were completely nonvisaulized by long-term imaging review. 27 of 28 completely embolised aneurysm were completely nonvisaulized, 1 of partially embolised aneurysm was recurred (2.7%); 4 of 9 partially embolised aneurysm were completely nonvisaulized, 4 were shrinking and 1 was stable; 2 of 4 aneurysms treated with stent only were completely nonvisaulized, 2 were shrinking.2.3.2 the influence of implanting stents on the artery carrying aneurysmThe effect on the new tunica intima on the aneurysm neck 25 of 80(31.3%) aneurysms were covered by new tunica intima in long-term review. 16 of 41(39.0%) with balloon-expanding stents were covered by new tunica intima; 9 of 39(23.1%) with self-expanding stents were covered by new tunica intima.The effect of stent on the wall of PA80 cases of artery carrying aneurysm were reviewed in the long-term period. 24 of 41(58.5%) with balloon-expanding stents were covered by new tunica intima; 14 of 39(35.9%) with self-expanding stents were covered by new tunica intima.The effect on the branch artery carrying stents70 cases of branch artery carrying stents were reviewed in the long-term period. One of them was occlusion, and one stenosis.3 Therapeutic effect in the clinical environment3.1 The clinical status when dischargeOne case of cerebral ischemia was happened. All the patients had no incidence of perforating branch and ischemia of the branch vessel. The neural status was showed by the mRS score. 142 of them were good with a rate of 90.8%, 10 of them had mild disability (6.54%); 2 of them had got serious disability (1.3%); 3 of them (1.96%) died during the in-patient time (2 of rehaemorrhagia preoperatively and 1 of severe vasospasm).3.2 The results of clinical follow-up142 of 150 patients (95.3%) were in good heath status with an average period of 45.4 months (16-65months) follow-up, 3 patients (2.0%) got mild disability, 2 of them (1.33%) had got serious disability, 2 patients (1.33%) died. Totally 4 cases (2.67%) of complications happened in the follow-up time, 2 patients (1.33%) died, one patient got hemiplegia after cerebral infarction (ceased the platelet aggregation inhibitor drugs by himself), 2 patients (1.33%) got rehaemorrhagia, and the disability rate is 0.67%. no the patients hadn't got any incidence of perforating branch and ischemia of the branch vessel.[Conclusions] Stenting of cerebral aneurysm is a safe treatment alternative. Meanwhile, the risk of the procedure and the perioperative morbidity is lower than some other researches found by literature review. It is showed by the clinical and imaging results that stent can improve the prognosis of the patients with wide-neck aneurysm; and the clinical application of stent is also secure to the parent artery as well as the branch vessels.
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