Symptomatic vertebral artery stent fracture: a case report

Percutaneous transluminal angioplasty (PTA) with stent placement is the preferred treatment modality at present for atherosclerotic stenotic lesions of vertebral artery origin. A complication of stent placement in the vertebral artery origin that has received little attention is the risk of stent fracture. A case with four-vessel pathology treated with PTA and stent placement in the left vertebral artery origin is presented. Symptoms recurred 4 months after stent placement, and arteriogram revealed a fractured stent, which was treated surgically with stent removal and vertebral artery-common carotid artery reimplantation.     

不同类型支架治疗椎动脉开口狭窄的对照研究

【摘要】　目的?比较不同类型支架治疗椎动脉开口狭窄的有效性和安全性。方法?2018年1月至2018年12月73例椎动脉开口狭窄患者共86条病变血管接受支架成形术治疗,分别应用肾动脉支架23枚,Apollo支架26枚,冠状动脉裸支架19枚,药物洗脱支架（DES）18枚。回顾性分析患者临床资料,对比不同类型支架植入术疗效和支架内再狭窄发生率。结果?不同类型椎动脉开口支架成形术均获成功。术前影像显示椎动脉开口平均狭窄率为90.9%,术后即刻影像显示平均残余狭窄率为10.3%。围术期手术相关并发症发生率为1.2%（1/86）。术后平均随访（6.2±3.1）个月,患者临床症状得到改善。肾动脉枚架失访1枚,再发狭窄4枚（17%）;Apollo枚架失访2枚,再发狭窄8枚（31%）,1例患者术后第2日并发大面积后循环脑梗死;冠状动脉裸枚架无失访,再狭窄7枚（37%）,1例患者6个月时枚架断裂;DES组失访1枚,再狭窄2枚（11%）,与其他组再发狭窄差异有统计学意义（P＜0.05）。结论?不同类型枚架治疗椎动脉狭窄安全有效。DES在降低枚架内再狭窄发生方面最优,肾动脉枚架次之,Apollo枚架和冠状动脉裸枚架再狭窄率较高。     

Endovascular treatment of extracranial vertebral artery stenosis

Percutaneous angioplasty and stenting for the treatment of extracranial vertebral artery(VA) stenosis seems a safe,effective and useful technique for resolving symptoms and improving blood flow to the posterior circulation,with a low complication rate and good long-term results.In patients with severe tortuosity of the vessel,stent placement is a real challenge.The new coronary balloon-expandable stents may be preferred.A large variability of restenosis rates has been reported.Drug-eluting stents may be the solution.After a comprehensive review of the literature,it can be concluded that percutaneous angioplasty and stenting of extracranial VA stenosis is technically feasible,but there is insufficient evidence from randomized trials to demonstrate that endovascular management is superior to best medical management.     

大动脉炎颈动脉狭窄球囊扩张和内支架的治疗

目的：探讨应用球囊扩张和血管内支架治疗大支脉炎、颈动脉狭窄、材料和方法：３例大动脉炎性颈动脉狭窄的患者，狭窄段均超过８ｃｍ，１例单纯球囊扩张；２例球囊扩张后植入Ｗａｌｌｓｔｅｎｔ支架。结果：术后狭窄率均为０，达到了良好的治疗效果，单纯球囊扩张的动脉一年后动脉完全闭塞、西入血管内支架的２例，分别是在４．５个月和４个月检查，一例血管内支架的近端出现了再狭窄，另一例未出现再狭窄。结论：对于大动脉炎性长段     

腔内支架成形术治疗症状性颅内动脉狭窄

目的研究腔内支架成形术治疗症状性颅内动脉狭窄的安全性及有效性。方法对7例症状性颅内动脉狭窄的患者行腔内支架成形术治疗。结果7例患者中6例成功置入8枚冠脉支架,1例因支架置入困难仅行经皮腔内血管成形术(PTA),6例患者术后均未发生脑缺血发作,2例患者术后3～8个月复查经颅多普勒超声(TCD)血流通畅,未见内膜过度增生,1例单纯PTA患者术后症状明显改善,1例基底动脉支架成形术后出现动眼神经麻痹。结论腔内支架成形术是治疗症状性颅内动脉狭窄的安全、有效的方法,其长期疗效还需进一步随防研究。     

Percutaneous transluminal angioplasty and stent placement for subclavian and brachiocephalic artery stenosis in aortitis syndrome

A 43-year-old man with progressive right common carotid, subclavian artery, and brachiocephalic artery stenoses due to aortitis syndrome is presented. The patient's right common carotid artery had been treated by percutaneous transluminal angioplasty (PTA) four times previously, but it was finally occluded. The right subclavian artery was treated by PTA once, which resulted in restenosis. The stenosis extended to the brachiocephalic artery. For this patient, PTA followed by stent placement was performed for the right subclavian and brachiocephalic artery stenosis. Because arterial stenosis is progressive in cases of aortitis syndrome, simple PTA alone does not appear to be sufficient for treatment. We suggest that PTA followed by stent placement may be an alternative treatment for recurrent stenosis in aortitis syndrome.     

Diffusion-weighted imaging abnormalities after percutaneous transluminal angioplasty and stenting for intracranial atherosclerotic disease

BACKGROUND AND PURPOSE: The literature contains relatively few reports of distal embolism associated with intervention for intracranial atherosclerotic disease. Our purpose was to evaluate the frequency of thromboembolic events after percutaneous transluminal angioplasty (PTA) or stent placement in this setting by using diffusion-weighted (DW) imaging. METHODS: Between October 1999 and January 2004, 16 consecutive patients with symptomatic intracranial arterial stenosis greater than 60% were treated with PTA or stent placement without a protection system. Whole-brain DW imaging was performed before and after intervention. DW imaging findings were retrospectively analyzed and divided into three groups according to new hyperintensities: type A was none; type B, a single lesion; and type C, multiple lesions. RESULTS: Nine type A, five type B, and three type C lesions were detected after the interventions. All hyperintense lesions were less than 5 mm in diameter. All type C lesions occurred in the context of internal carotid artery stenosis treated with stent placement. DW imaging abnormalities occurred most frequently when PTA followed by stent placement was performed for long internal carotid artery stenoses. No new neurologic deficits occurred in any patient. CONCLUSION: In this series, PTA or stent placement or both for intracranial atherosclerotic lesions was safe. New DW imaging abnormalities were less frequent in patients who underwent PTA alone or primary stent placement than in those receiving PTA followed by stent placement.     

四肢动脉狭窄伴血栓形成的急诊介入治疗

目的 评价四肢动脉狭窄伴血栓形成急诊介入治疗的临床意义。方法 26例四肢动脉狭窄伴血栓形成的患者实施了急诊OASIS导管流变溶栓、ATD浸软溶栓或尿激酶溶栓术，对狭窄段采取经皮球囊扩张(PTA)和支架成形术，其中锁骨下动脉3例，髂动脉5例，股动脉7例，胭动脉4例，胫前胫后动脉及足部动脉4例，人造血管2例，支架术后再狭窄1例。结果 PTA或支架置入术后狭窄段的血管腔复通率100％，溶栓术后血栓完全消失，患肢远端血运明显改善或恢复，临床症状消失。DSA或B超随访1～20个月，动脉均保持通畅。溶栓后消化道出血1例，无截肢病例。结论 采用急诊机械性和药物性溶栓术结合PTA和支架治疗四肢动脉狭窄伴血栓形成，可有效地解除动脉闭塞，避免截肢。     

Efficacy of stent angioplasty for symptomatic stenoses of the proximal vertebral artery

BACKGROUND: To evaluate the safety and efficacy of stent angioplasty in the treatment of symptomatic arteriosclerotic stenoses of the proximal vertebral artery (VA). METHODS: Thirty-eight symptomatic stenoses of the vertebral origin were treated with flexible balloon-expandable coronary stents. Angiographic and clinical follow-up examinations were obtained in 26 patients at a mean of 11 months. RESULTS: The immediate post-procedural angiographic results showed no residual stenosis in 33 vessels and mild residual stenoses in five vessels. Periprocedurally, there were two asymptomatic technical complications and one TIA. During follow-up re-stenosis could be detected in 10 cases (36%), and vessel occlusions in two patients. Two stents were broken. One of the restenosis caused a TIA within the follow-up period. CONCLUSIONS: Flexible balloon-expandable coronary stents proved to be save and effective in preventing vertebrobasilar stroke but were incapable to preserve the proximal vertebral artery lumen. For the VA origine an adequate stent, self-expanding, bioresorbable, or drug-eluting has to be found.     

Midterm results of renal artery stenting

Percutaneous transluminal angioplasty (PTA) has become the treatment of choice for major renal artery stenosis. Nonetheless, about 10% of renal artery stenoses cannot be properly dilated, and among the patients successfully dilated, 10%–15% had a recurrence. Renal artery stenting was used in 21 patients in cases of insufficient results after PTA: persisting significant stenosis after a primary or several PTAs (15 cases), recurrences (9 cases). Follow-up in all patients was from 12 months to 4 years. Implantation was performed without any problems but the low radioopacity of the stent makes placement difficult in obese patients, particularly for ostial lesions. There was no major complication except occlusion of a segmental branch of the renal artery in 1 case. Radiological controls have shown a preserved patency in all cases except 2, which present restenosis inside the stent by intimal hyperplasia. A significant clinical improvement was obtained in 90% of cases. These results suggest that the endovascular prosthesis represents an important adjunct to renal PTA.     

球囊扩张支架治疗椎动脉起始部重度狭窄的围手术期风险和短期预后

目的探讨采用球囊扩张支架治疗椎动脉起始部重度狭窄的围手术期风险及短期预后。方法 2010年1月-2011年9月收治27例后循环缺血患者,29处症状性椎动脉起始部狭窄率≥70%,因常规药物治疗无效,采用球囊扩张支架进行治疗。术后1、3、6、9、12个月进行随访,监测血脂、血糖、血压。术后6个月复查动脉超声,12个月时复查DSA。结果 27例患者的29处重度狭窄均成功置入球囊扩张支架,技术成功率100%。术前狭窄率80%～99%,平均92.55%±5.26%,中位狭窄率95%;术后狭窄率0%～15%,平均3.27%±4.60%,中位狭窄率0%,手术并发症0。术后随访12个月时,无后循环缺血事件发生。12个月时随访DSA,支架内内膜增生1例,再狭窄0例。结论应用球囊扩张支架治疗椎动脉起始部重度狭窄围手术期并发症发生率低,短期预后良好。     

Endovascular treatment of atherosclerotic arterial stenoses and occlusions of the supraaortic arteries: mid-term results from a single center analysis

OBJECTIVE: To determine mid-term patency rates after endovascular treatment of supraaortic atherosclerotic arterial stenoses and occlusions using percutaneous transluminal angioplasty (PTA) and stent placement. PATIENTS AND METHODS: During a period of 83 months, 48 patients (18 female, 30 male; mean age 61 years, range 31-82 years) were included into this prospective single-center study. Fifty-five lesions of the brachial and cephalic arteries (subclavian/axillary artery n = 42, innominate artery n = 7, origin common carotid artery n = 6) were treated using PTA (n = 38), PTA plus stent (n = 11) or primary stent placement (n = 6). For anticoagulation, patients received a bolus of heparin (5000 IU) intraarterially during the intervention followed by intravenous application for 24h. At discharge, life-time application of ASA (100mg/day) was initiated. Follow-up protocol included clinical examination, colour-coded duplex ultrasound and intraarterial angiography in case of re-stenosis. RESULTS: PTA and stent placement were technically successful in all patients (100%). No major complications occurred. Of seven patients presenting with total occlusions, six were treated with stent placement. Stent implantation was also performed in all lesions located at the origin of the supraaortic arteries (n = 6). In 38 lesions, the result of PTA was satisfactory. Mean follow-up time is 22 months (range 1-83 months). During follow-up examinations, re-stenoses occurred in 10 cases (at 1 month n = 2, at 6 months n = 2, at 12 months n = 3, at 24 months n = 3). In 9 lesions, re-interventions were performed (PTA n = 7; PTA plus stent n = 2). According to Kaplan-Meier life-table analysis, cumulative primary and primary assisted patency rates are 69.5% (patients at risk n = 15; standard error 9%) and 90.6% (patients at risk n = 16; standard error 6.3%) at 20 months, respectively. CONCLUSIONS: Endovascular treatment of atherosclerotic obstructive disease in brachial and cephalic arteries is a safe procedure showing promising mid-term patency rates.     

Angioplasty with or without Stent Placement in the Brachiocephalic Artery: Feasible and Durable? A Retrospective Cohort Study

PURPOSE: To evaluate the results of percutaneous transluminal angioplasty (PTA) and stent placement in isolated brachiocephalic trunk lesions. MATERIALS AND METHODS: PTA, with or without stent placement, was used to treat 30 patients with isolated clinically significant stenoses (n = 25) or occlusions (n = 5) of the brachiocephalic artery. Initial clinical success was defined as a relief or substantial reduction of the preprocedural symptoms, and initial technical success was defined as a mean translesion pressure gradient of less than 5 mm Hg or a residual stenosis of less than 20%. Clinical evaluation and duplex Doppler ultrasonography of the lesion site were performed at follow-up. Clinical restenosis was defined as recurrent clinical symptoms and a lumen reduction of more than 50%, determining the primary clinical patency. Technical restenosis was defined as more than 50% lumen reduction with or without renewed clinical symptoms, determining the primary technical patency. RESULTS: The initial technical success rate was 83% (occlusions, 60%; stenoses, 88%), and the clinical success rate was 81%. Two patients had major complications, and four experienced minor complications. At a median follow-up of 24 months (4 weeks to 92 months), the primary clinical patency rate was 79% (95% confidence interval [CI]: 57%, 104%), with 83% (95% CI: 60%, 105%) for arteries with stents and 67% (95% CI: 13%, 120%) for those without stents (P = .11). The primary technical patency rate was 50% (95% CI: 24%, 76%). CONCLUSION: PTA with or without stent placement in a stenotic or occlusive brachiocephalic artery is a procedure of tolerable safety with a high initial success rate; however, only moderately rewarding results were obtained after 2 years. Selective stent placement probably improves long-term success. Primary PTA with selective stent placement in an atherosclerotic obstructive brachiocephalic artery should be considered the preferred treatment option.     

Combined stent placement and thrombolysis in acute vertebrobasilar ischemic stroke

BACKGROUND AND PURPOSE: Acute vertebrobasilar ischemic stroke is often associated with high morbidity and mortality with limited therapeutic options. Endovascular treatment with thrombolysis has offered some hope for affected patients; however, overall outcomes have been less than satisfactory. In this report, we present the results of our approach in six consecutive cases of acute vertebrobasilar ischemic stroke by combined proximal vessel stent placement and thrombolysis. METHODS: Six consecutive cases were retrospectively reviewed for the clinical outcome of patients presenting to our institution with acute posterior circulation stroke who underwent cerebral revascularization including proximal arterial stent placement by using balloon-expandable coronary stents and intraarterial thrombolysis. All of these patients were initially evaluated by stroke team neurologists and imaged with MR, including diffusion-weighted imaging documenting acute posterior circulation stroke. MR angiography of the circle of Willis was also obtained. Short-term follow-up was conducted to assess National Institutes of Health stroke scores (NIHSS) and modified Rankin scores. RESULTS: In these six cases, a combined approach of proximal arterial stent placement (five cases of vertebral artery origin and one case of carotid and subclavian stent placement plus vertebral artery revascularization) and thrombolysis was performed at variable times after stroke onset (range, 30 hours to 5 days). Four of the six patients had good basilar artery recanalization (Thrombolysis in Myocardial Infarction [TIMI] grade 0-1 before tissue plasminogen activator thrombolysis and TIMI grade 2 after procedure). Four of six patients had excellent immediate recovery and were discharged to an acute rehabilitation unit or their homes with improved neurologic symptoms and functional status. Two patients died: one patient presented with coma at outset with an NIHSS of 38, and the other patient probably had reocclusion of the basilar artery within 24 hours despite initial postprocedural improvement. CONCLUSION: We demonstrate that, in the setting of acute stroke, stent placement in combination with revascularization and thrombolysis is practical and allows quick access to a clot and simultaneously increases perfusion through collaterals during the thrombolytic process. In particular, basilar thrombolysis may be facilitated by proximal vertebral stent placement as concomitant atheromatous vertebrobasilar stenosis is common.     

Endovascular treatment for recurrent carotid stenosis]

PURPOSE: Surgery of recurrent carotid stenosis (RCS) has higher complication rates than primary carotid endoarterectomy (CEA). Percutaneous transluminal angioplasty (PTA) and stent placement were evaluated retrospectively with a view to proposing then as alternative procedures for RCS. METHODS: In the last 10 years, 19 patients underwent 20 endovascular procedures for RCS at our Department. The mean interval between CEA and PTA was 21 months (range 4-96): 14 patients had PTA within 2 years, 3 patients within 2 and 3 years,and 2 after 3 years. The mean degree of stenosis was 92% (range 80-95%). PTA was performed by balloon catheters (size 4-7 mm) without using cerebral protection device; one self-expanding stent was used to treat RCS after PTA. All patients underwent physical examination and carotid color-coded Doppler sonography in autumn 1999 RESULTS: The procedure was technically successful, with residual stenosis lower than 50%, in 17 of 19 patients; 10 patients showed residual stenosis lower than 30%. Carotid PTA was stopped due to transient neurological deficit in one case. One RCS proved uncompliant even though high-pressure balloon catheters were used. The mean follow-up period in 16 patients was 37.4 months (range 3-99 months). Carotid restenosis after PTA developed in 3 patients, respectively after 29,18 and 7 months. In the last case RCS was successfully treated by stent placement (Wallstent). The primary patency rate was 81%, the secondary patency rate was 88% and the late clinical success rate was of 94%. CONCLUSIONS: In selected cases, PTA without the use of cerebral protection devices and stent placement proved to be a safe and effective alternative treatment for early RCS. When an atherosclerotic lesion is suspected surgery or endovascular treatment with cerebral protection devices are recommended.     

Stent placement for renal arterial stenosis: where do we stand? A meta-analysis

PURPOSE: To perform a meta-analysis of renal arterial stent placement in comparison with renal percutaneous transluminal angioplasty (PTA) in patients with renal arterial stenosis. MATERIALS AND METHODS: Studies dealing with renal arterial stent placement (14 articles; 678 patients) and renal PTA (10 articles; 644 patients) published up to August 1998 were selected. A random-effects model was used to pool the data. RESULTS: Renal arterial stent placement proved highly successful, with an initial adequate performance in 98% and major complications in 11%. The overall cure rate for hypertension was 20%, whereas hypertension was improved in 49%. Renal function improved in 30% and stabilized in 38% of patients. The restenosis rate at follow-up of 6-29 months was 17%. Stent placement had a higher technical success rate and a lower restenosis rate than did renal PTA (98% vs 77% and 17% vs 26%, respectively; P <.001). The complication rate was not different between the two treatments. The cure rate for hypertension was higher and the improvement rate for renal function was lower after stent placement than after renal PTA (20% vs 10% and 30% vs 38%, respectively; P <.001). CONCLUSION: Renal arterial stent placement is technically superior and clinically comparable to renal PTA alone.     

Drug-eluting stent insertion in the treatment of in-stent renal artery restenosis in three renal transplant recipients

Percutaneous transluminal angioplasty (PTA) with or without stent insertion is the treatment of choice in transplant renal artery stenosis. However, in-stent restenosis occurs in as many as 13% of patients after PTA and stent insertion. This article describes three patients with recurrent transplant renal artery in-stent stenosis who were treated with paclitaxel-eluting stents. In two patients, the transplant renal artery remained patent after insertion of the drug-eluting stent (DES), and one patient required balloon angioplasty 7 months after the DES was inserted.     

Stent-assisted angioplasty of symptomatic intracranial vertebrobasilar artery stenosis: feasibility and follow-up results

BACKGROUND AND PURPOSE: The natural history of symptomatic, untreated posterior circulation stenosis is dismal, with many patients experiencing significant morbidity or mortality. The purpose of this study was to evaluate the feasibility and results of stent-assisted angioplasty of symptomatic intracranial vertebrobasilar artery stenosis.METHODS: We reviewed the imaging findings and medical records of 17 consecutive patients who were treated with stent-assisted angioplasty for medically refractory vertebrobasilar artery stenosis. The location of the lesion, degree of stenosis, procedure-related complications, and clinical and short- and long-term angiographic results were assessed.RESULTS: The population included 17 cases (10 men, seven women; age range, 51–74 years; mean, 64 years). The locations of the lesions were intracranial vertebral artery (n = 13) and basilar artery (n = 6). The mean degree of stenosis decreased from 76.1 ± 14.6% before stent-assisted angioplasty to 1.3 ± 2.8% (P < .05) after the procedure. Acute in-stent thrombosis developed in one case (6%, Mori type B lesion), which was successfully treated with intraarterial abciximab infusion and angioplasty. Another patient (6%, Mori type C lesion) developed immediate postprocedural transient diplopia and ataxia, which gradually resolved. No other patient showed symptoms related to the vertebrobasilar artery lesion at follow-up. No significant restenosis was observed at short-term (five patients; follow-up range, 0.5–6 months; mean, 4.3 months) or long-term (six patients; follow-up range, 12–41 months; mean, 21 months) angiographic follow-up.CONCLUSION: Stent-assisted angioplasty is a feasible treatment method for vertebrobasilar artery stenosis. The patency of the stent-assisted angioplasty seems to be preserved in the long-term, with good clinical outcome.

The natural history of untreated posterior circulation stenosis is dismal, with many patients experiencing significant morbidity or mortality (1–3). Retrospective data suggest that the annual stroke rates for patients with symptomatic intracranial vertebral or basilar artery stenosis are 7.8% and 10.7%, respectively, despite anticoagulation or antiplatelet therapy (3).Recently, percutaneous transluminal angioplasty was proposed as a promising alternative treatment for patients with intracranial atherosclerotic stenosis symptoms despite medical therapy. However, percutaneous transluminal angioplasty has had the problems of dissection, elastic recoil, and thrombosis (4, 5). In a series of 42 cases of angioplasty for intracranial stenosis by Mori et al (4), the 1-year angiographic restenosis rate in type A (short, ≤5 mm in length, concentric or moderately eccentric lesions not totally occlusive), type B (tubular, 5–10 mm in length, extremely eccentric or totally occluded lesions, <3 months old), and type C (diffuse, >10 mm in length, extremely angulated [>90°] lesions with excessive tortuosity of the proximal segment, or totally occluded lesions, and ≥3 months old) lesions were 0%, 33%, and 100%, respectively, with cumulative risk of fatal or nonfatal ipsilateral ischemic stroke in 8%, 12%, 56%, respectively, at 1 and 2 years.Stent-assisted angioplasty has been limited mainly by the apprehension concerning the technical feasibility, periprocedural complications, and short- and long-term outcomes (6). Major problems still exist; nonetheless, recent technical advances in instruments used for angioplasty and stent placement have allowed easier trackability through the small and tortuous intracranial vessels. Also, experience from the earlier works of intracranial angioplasty and stent placement has allowed a relatively safe procedure with fewer periprocedural complications (7–14).We reviewed our experience with stent-assisted angioplasty for medically refractory intracranial vertebral and basilar artery stenoses, including the intra- and periprocedural complications and long-term angiographic and clinical outcomes.     

Cutting balloon angioplasty for resistant renal artery in-stent restenosis

A 76-year-old woman presented with recurrent arterial hypertension 6 months after uncomplicated primary renal artery stent placement. Diagnostic arteriography revealed severe renal artery in-stent restenosis. On repeat intervention, the lesion was resistant to attempted conventional percutaneous transluminal angioplasty (PTA) with unchanged systolic pressure gradients across the stent. Cutting balloon angioplasty (CBA) was performed with use of a 4-mm cutting balloon (IVT, San Diego, CA). CBA successfully reduced the pressure gradient to below the level of significance. Subsequent conventional PTA enhanced the lumen diameter inside the stent. The arterial hypertension reverted to normal values and duplex ultrasonography (US) at 10-month follow-up demonstrated normal renal artery hemodynamics without stenosis. CBA for potential use in renal artery in-stent restenosis and other peripheral neointimal hyperplasia is discussed.     

肝移植术后血管胆道并发症的介入治疗

目的:评价介入治疗对肝移植后胆道、血管并发症的价值。材料和方法:18例肝移植患者接受了介入治疗。其中肝动脉狭窄8例,行肝动脉造影及溶栓治疗;下腔静脉及肝静脉狭窄2例,行内支架置入术;胆瘘及胆道狭窄8例,行PTCD治疗。结果:胆道并发症8例,PTCD治疗后症状消失;肝动脉狭窄8例,溶栓后肝动脉完全开放6例,1例血流部分开放,1例肝动脉血流未恢复再次肝移植治疗;下腔静脉及肝静脉狭窄2例内支架置入术后下腔静脉梗阻及肝肿大症状消失。结论:介入治疗是治疗肝移植后胆道血管并发症的有效方法。