Inhibition of experimental neointimal hyperplasia by recombinant human thrombomodulin coated ePTFE stent grafts

OBJECTIVES: The goal of this study was to evaluate the ability of recombinant human thrombomodulin (rTM) to inhibit neointimal hyperplasia when bound to expanded polytetrafluoroethylene (ePTFE) stent grafts placed in a porcine balloon injured carotid artery model. METHODS: The left carotid artery of male pigs, weighing 25 to 30 Kg, was injured with an angioplasty balloon. Two weeks later either a non-coated standard ePTFE stent graft (Viabahn, 6 x 25 mm, W. L. Gore & Associates) or a rTM coated stent graft was implanted into the balloon-injured segment using an endovascular technique. Carotid angiography was performed at the time of the balloon injury, two weeks later and then at 4 weeks to assess the degree of luminal stenosis. One month after stent graft deployment, the grafts were explanted following in situ perfusion fixation for histological analysis. The specimens were then cross-sectioned into proximal, middle and distal segments, and the residual arterial lumen and intimal to media (I/M) ratios were calculated with computerized planimetry. RESULTS: rTM binding onto ePTFE-grafts was confirmed by functional activation of protein C and histopathology with immuno-scanning electron microscopy, backscatter electron emission imaging and x-ray microanalysis. All seven of the rTM coated stent grafts and six of the seven uncoated stent grafts were patent at the time of explantation. The mean luminal diameter of the rTM coated stents was 93% +/- 2.0% of the original diameter, compared with 67% +/- 23% (P = .006) in the control group. Histological analysis demonstrated that the area obliterated by intimal hyperplasia at the proximal portion of the rTM stent was -27% compared with the control group: (2.73 +/- 0.69 mm(2), vs 3.47 +/- 0.67 mm(2), P <.05). CONCLUSIONS: Neointimal hyperplasia is significantly inhibited in ePTFE stent grafts coated with rTM compared with uncoated grafts, as documented by improved luminal diameter by angiography and by computerized planimetry measurements of residual lumen area. These findings suggest that binding of recombinant human thrombomodulin onto ePTFE grafts may improve the long-term patency of covered stents grafts. CLINICAL RELEVANCE: Decrease of neointimal hyperplasia of the magnitude observed in this study could significantly improve blood flow and patency of small caliber prosthetic grafts. If the durability of these results can be confirmed by long-term studies, this technique may prove useful in preventing graft stenosis and arterial thrombosis following angioplasty or vascular bypass procedures.     

Salvage of thrombosed dialysis access grafts with venous anastomosis stents

BACKGROUND: Thrombosis of arteriovenous (AV) grafts caused by stenosis at the venous anastomosis is a well-described problem. Surgical thrombectomy and conventional angioplasty with mechanical thrombectomy have provided good success rates in achieving immediate graft patency but with generally dismal graft survival rates in the range of 11% to 36% at 6 months' follow-up. The role of intravascular stents in patients who have failed angioplasty or surgical revision at the venous anastomosis has not been fully elucidated, particularly in older grafts that have previously undergone multiple procedures. METHODS: In this series, 34 patients had self-expanding nitinol stents placed at the venous anastomosis following graft thrombectomy and angioplasty procedures. Patients were selected for stent placement if conventional angioplasty alone was unsuccessful due to immediate elastic recoil or residual stenosis. All patients were followed after stent placement and evaluated for duration of graft patency and need for repeated endovascular procedures. RESULTS: The average graft age at the time of stent placement was 17.9 months. Eight-eight percent of grafts were functioning at 6 months' follow-up, and 63% of the entire group had survived without the need for additional procedures. Among those with need for repeat interventions, 81% had new lesions outside of the stent, and 57% had new lesions within the stent. In 38% of cases, new stenoses were located both outside and within the stent. Among grafts no longer being used, only 19% of the time was it due to disease recurring within the stent. CONCLUSION: Polytetrafluoroethylene (PTFE) graft longevity is improved when venous anastomosis stenoses are treated with stents in selected cases of older grafts that would have normally undergone abandonment or surgical revision.     

A New Technique for Reconstruction of the Common Bile Duct by an Autologous Vein Graft and a Biodegradable Endoluminal Stent

The incidence of severe bile duct injuries has significantly increased since the introduction of laparoscopic cholecystectomy. The ideal reconstruction procedure for traumatic defects of the bile duct should be technically simple and should preserve both the physiological passage of bile and the sphincter of Oddi. In this article we describe a new technique for bile duct reconstruction in a pig model by means of an autologous vein graft that is splinted by a endoluminal biodegradable polylactate acid stent. In 12 pigs the external jugular vein was removed and used as an autologous vein graft. After performing a median laparotomy a 2-cm segment was resected from the bile duct. The common bile duct was reconstructed by a venous interponate that had been endoluminally stented by a biodegradable polylactate acid stent. For the examination of stent degradation, 2 pigs were sacrificed at 3, 4, and 5 months (stent degradation group) and the remaining 6 pigs at 6 months (survival group). All the pigs in the survival group survived for 6 months before being sacrificed. After 4 months the stent material had been completely broken down and the vein graft had been relined with bile duct epithelium. Thus, this new technique for bile duct reconstruction using an autologous vein graft with an endoluminal stent is simple to perform and reliable, and constitutes an interesting alternative to bilodigestive anastomosis due to the preservation of the papilla of Vateri.     

A new technique for reconstruction of the common bile duct by an autologous vein graft and a biodegradable endoluminal stent.

The incidence of severe bile duct injuries has significantly increased since the introduction of laparoscopic cholecystectomy. The ideal reconstruction procedure for traumatic defects of the bile duct should be technically simple and should preserve both the physiological passage of bile and the sphincter of Oddi. In this article we describe a new technique for bile duct reconstruction in a pig model by means of an autologous vein graft that is splinted by a endoluminal biodegradable polylactate acid stent. In 12 pigs the external jugular vein was removed and used as an autologous vein graft. After performing a median laparotomy a 2-cm segment was resected from the bile duct. The common bile duct was reconstructed by a venous interponate that had been endoluminally stented by a biodegradable polylactate acid stent. For the examination of stent degradation, 2 pigs were sacrificed at 3, 4, and 5 months (stent degradation group) and the remaining 6 pigs at 6 months (survival group). All the pigs in the survival group survived for 6 months before being sacrificed. After 4 months the stent material had been completely broken down and the vein graft had been relined with bile duct epithelium. Thus, this new technique for bile duct reconstruction using an autologous vein graft with an endoluminal stent is simple to perform and reliable, and constitutes an interesting alternative to bilodigestive anastomosis due to the preservation of the papilla of Vateri.     

Outcomes of thrombosed arteriovenous grafts: comparison of stents vs angioplasty

The usual radiologic approach to thrombosed grafts is a combination of thrombectomy and angioplasty of the underlying lesion. However, the primary (unassisted) graft patency after thrombectomy is quite poor. We evaluated whether graft patency following thrombectomy is improved by placement of a stent in the stenotic lesion. Using a prospective, computerized vascular access database, we identified 14 patients with thrombosed arteriovenous (A-V) grafts treated with a stent at the venous anastomosis (stent group). The outcomes of these grafts was compared to those observed in 34 sex, age-, and date-matched control patients whose thrombosed A-V grafts were angioplastied (control group). Both groups were comparable in age, sex, race, diabetic status, graft age, and number of previous graft interventions. The immediate technical success, as indicated by the post-procedure graft to systemic pressure ratio, was similar in the stent and control groups (0.33+/-0.16 vs 0.41+/-0.17, P=0.14). The primary graft patency (time from thrombectomy to next intervention) was significantly longer for the stent group (median survival, 85 vs 27 days, P=0.02). Assisted or secondary patency (time from thrombectomy to permanent graft failure) was also longer for the stent group (median survival, 1215 vs 46 days, P=0.049). In conclusion, treatment of thrombosed grafts with a stenosis at the venous anastomosis with a stent results in longer primary and secondary graft survival, as compared to treatment with angioplasty. Stent placement may be a useful treatment modality in a subset of patients with thrombosed A-V grafts and stenosis at the venous anastomosis.     

Treatment of extracranial and intracranial aneurysms and arteriovenous fistulae using stent grafts

OBJECTIVE: Treatment of 11 patients with aneurysms or arteriovenous fistulae of the craniocervical arteries with stent grafts. METHODS: Peripheral stent grafts were deployed in two extracranial internal carotid arteries. Coronary stent grafts were used to treat two giant aneurysms, five direct carotid-cavernous fistulae, one vertebrojugular fistula, and two dissecting aneurysms of the vertebral artery (V2 and V4). RESULTS: Stent grafts were used successfully in two extracranial internal carotid and two extracranial vertebral arteries, one dissecting aneurysm of the intracranial vertebral artery, one giant aneurysm and one pseudoaneurysm of the cavernous internal carotid artery, and five direct carotid-cavernous sinus fistulae. Angiographic follow-up examinations (available in nine patients; obtained at 3 mo to 5 yr; average, 24 mo) revealed normal vessel caliber, and the stent grafts in all 9 of 11 initial patients were patent. There was a recurrent saccular aneurysm adjacent to the stent graft in the patient with the intracranial vertebral artery aneurysm. The following five complications were encountered: transient hemiparesis (n = 2), increased hemiparesis, postprocedural management-related fatality, and ICA dissection. In six patients, stent graft deployment was accomplished without any technical or clinical complication. There were no permanent neurological deficits consequent to stent graft placement. CONCLUSION: Stent grafts are a useful tool for the endovascular treatment of head and neck aneurysms and direct arteriovenous fistulae in selected patients. The major disadvantage of the currently available stent grafts is their lack of mechanical flexibility. Maneuvering stent grafts in the intracranial arteries carries the risk of iatrogenic vessel dissection and may require supportive measures and protection of the target site by conventional stents.     

Use of stents and stent grafts to salvage angioplasty failures in patients with hemodialysis grafts

To determine the efficacy of using stents and stent grafts for treatment of hemodialysis graft-related stenoses which have failed angioplasty. This retrospective study was composed of 51 patients with polytetrafluoroethylene hemodialysis grafts who underwent angioplasty of a graft-related stenosis but subsequently required insertion of a stent or stent graft. The study group included 40 patients with >30% residual stenosis and 11 patients with angioplasty-induced venous ruptures. The patient's medical records and radiology reports were reviewed. Patient demographics, indication for stent placement, and the type of stent were recorded. Stent patency was determined using Kaplan-Meier analysis. A total of 70 stents were used; most (57.7%) were deployed across the venous anastomosis. A variety of different types of stents and stent grafts were used including 26 SMART, 18 Viabahn, 13 aSpire, and 13 other stents. The technical success rate for insertion of the device was 100%. Following insertion of the device the primary patency of the vascular access was 81%, 70%, and 54% at 1, 3, and 6 months, respectively. The secondary patency of the vascular access was 89%, 82%, and 74% at 3, 6, and 12 months, respectively. The primary patency of the stent or stent graft was 96%, 93%, 87%, and 47% at 1, 3, 6, and 12 months, respectively. Stents and stent grafts are useful for salvaging failed angioplasty procedures and thereby maintaining patency of the hemodialysis graft. By inserting a stent, the resultant patency rates are similar to those following a successful angioplasty procedure. Importantly, the primary patency of the stent was substantially better than the primary patency of the entire vascular access.     

胆总管囊状扩张超声分型及其临床意义

目的 对胆总管囊状扩张的声像图进行分类。并对各类型声像诊断特点及其临床意义进行探讨。方法 对65例胆总管囊状扩张患者超声检查的声像表现及其它临床资料进行总结分析。结果 胆总管囊状扩张患者65例。男18例,女47例,平均年龄8.9岁,根据胆总管囊状扩张的声像特点将其声像分为5种类型：A型;胆总管呈梭形扩张,21例,占32.3%;B型：胆总管呈球形扩张,16例,占24.6%;C型;胆总管扩张显著,表现为右上腹部的囊性肿物,22例,占33.8%;D型;胆总管重度扩张。表现为腹部巨大囊性肿物,6例,占9.2%;E型;胆总管囊状扩张合并肝内胆管囊状扩张。10例,占15.4%。结论 超声检查是诊断胆总管囊状扩张的首选影像学方法,A型和B型是胆总管囊性扩张程度较轻的二种情况,在这二型的病例,声像图中可以清晰地显示肝外胆管结构。故较容易做出诊断。C型和D型是胆总管扩张程度较重的类型。表现为腹部囊性肿物,超声诊断有一定难度,需要与其它病变进行鉴别,E型扩张的肝内、外胆管常延续相通,超声容易明确诊断。     

Prophylactic antibiotics prior to bacteremia decrease endovascular graft infection in dogs

Endovascular placement of vascular stent grafts in the aorta and peripheral vessels has become a prominent tool in the armamentaria of the vascular surgeon. Despite, several reports of stent graft infection, no current guidelines exist regarding the administration of antibiotics prior to episodes of potential bacterial seeding. We sought to clarify the role of prophylactic antibiotics in preventing stent graft infection after the parenteral administration of Staphylococcus aureus (S. aureus) at various intervals following device placement. A stent graft device was constructed from a 4 mm thin-walled polytetrafluoroethylene (PTFE) graft attached to the outside of a balloon expandable 394-Palmaz stent (Johnson and Johnson Interventional Systems, Warren, NJ). It was then inserted into the common iliac artery through an 11F peal-away sheath placed in the femoral artery. Sixty grafts were placed into 30 dogs. There were 5 groups of equal number (groups A-E). In group A, six dogs received intravenous injection of 3 cc x 104 CFU (colony forming units), biotype 31375 S. aureus, 1 day after stent graft implantation. An identically treated group B received antibiotic prophylaxis (1 gm cefazolin 30 minutes prior to bacterial challenge). Group C received bacterial injection 7 days after graft implantation with no antibiotic prophylaxis. Group D received bacterial injection 7 days after graft implantation with antibiotic prophylaxis. A control group E received no antibiotics and was not infected. All infected animals were sacrificed 7 days following bacterial challenge and the stent graft complex cultured. One half of the control group was sacrificed at 7 days and the other half at 14 days. The overall stent graft patency was 90%. Four of the six graft occlusions occurred in group A. Eleven of 12 (92%) dogs cultured S. aureus (biotype 31375) from the explanted stent graft complex. Two localized perforations occurred at the site of the infected complex. In group B, C, and D, no explanted graft complex cultured S. aureus. One graft occluded in group C and D. No stent graft in the control (group E) cultured S. aureus. A stent graft infection model can be consistently produced. In the canine model, the stent graft is more susceptible to infection in the early postoperative period and becomes less susceptible to bacterial seeding at one week after implantation. The authors recommend the use of prophylactic antibiotics in the prevention of endovascular graft infections in the early postoperative period during times when bacterial seeding may occur. They postulate that pseudointima formation during graft incorporation into the vessel wall may be responsible for the resistance to infection.     

Reconstruction of bile duct lesions by an autologous vein graft and a bio-degradable endoluminal stent in an animal model: technique and clinical impact

INTRODUCTION: In this study a new treatment of bile duct lesions was investigated. A segment of the bile duct was replaced by an autologous venous interponate which had been endoluminally stented with a braided bio-degradable stent. METHODS: A total of 18 pigs (20-28 kg) was divided into three equal groups (I-III). In each group a 2 cm segment of the jugular vein was harvested. The animals in Group I (vein group, n = 6) underwent resection of a 2 cm long segment of the common bile duct which was replaced solely by the venous interponate, in Group II (stent group, n = 6) the venous interponate had been endoluminally stented by a braided bio-degradable stent. Group III (control group, n = 6) underwent only a circular mobilization of the common bile duct. Postoperatively survival rate, general condition as well as the weight were observed and checked for 6 months. During surgery and finally after sacrifice after 6 months blood and tissue samples were taken and semiquantitatively scored concerning grade of inflammation and fibrosis. RESULTS: In the stent and control group all animals survived in good condition. 3 pigs of the vein group died within 3 weeks showing signs of biliary peritonitis, another one died due to a high grade stenosis of the common bile duct with secondary biliary cirrhosis after 4 months. In the stent group all animals survived until sacrifice after 6 months. On examination the venous interponate was laminated with bile duct epithelium showing the diameter of the implanted stent. CONCLUSION: The reconstruction of bile duct lesions by a venous interponate in combination with a bio-degradable stent is easy to perform and represents a clinically interesting alternative to the biliodigestive anastomosis because of the preservation of the sphincter oddi. After 6 months the stent is completely absorbed and the venous interponate is laminated with bile duct epithelium.     

大鼠气管上皮耐受热缺血时限的研究

目的 探讨肺移植无心跳供者气管上皮耐受热缺血的时限.方法 将SD大鼠分为4组.对照组在大鼠有心跳的情况下取出气管,热缺血30 min组、45 min组和60 min组分别在处死大鼠后30、45和60 min时取出气管,然后将供者气管固定后分别植入相应受者的大网膜内.14 d后,取出气管,进行病理学检查,并对上皮再生情况进行评分.结果 热缺血30min组和对照组比较,无论是上皮厚度还是黏膜上皮细胞层数的差异均无统计学意义(P>0.05);虽然45 min组与对照组相比,上皮厚度的差异有统计学意义(P<0.05),但45 min组的气管上皮有正常黏膜结构,并且与对照组相比,上皮细胞层数差异无统计学意义(P<0.05);而热缺血60min组,看不到正常的上皮结构,上皮也仅由1～2层黏膜上皮细胞覆盖.结论 气管耐受热缺血的时限可能为45 min.

Abstract：

Objective To determine the length of warm ischemic (WI) tolerance in bronchial graft from non-heart-beating donors. Methods Forty-eight rats were randomly divided into 4 groups (each group having 12 rats) according to different WI durations including WI-0 min (group A), WI-30 min (group B), WI-45 min (group C) and WI-60 min (group D). In each group, the tracheae from 6 rats were respectively imbedded in greater omentum of other 6 rats, and 14 days later, the transplanted tracheae were taken from recipients to evaluate epithelial thickness and regeneration. Results Epithelial thickness and the degree of epithelial regeneration had no significant difference (P >0. 05) between the syngeneic control group and the WI-30 minutes group. All of the grafts with WI duration of 45 min were viable, but the epithelium was significantly thinner than that in the syngeneic control group (P<0. 05). However all of the grafts with WI duration of 60 min showed lower viability rate. Conclusion The time limits of tolerance to WI of tracheal grafts from NHBDs may be 45 min.     

Patterns of flap loss related to arterial and venous insufficiency in the rat pedicled TRAM flap.

Vascular supply to the contralateral portion of the conventional transverse rectus abdominis musculocutaneous (TRAM) flap (zone IV) may become compromised, resulting in partial flap loss and requiring segmental excision. The etiology of this necrosis is not clear. This study determines skin necrosis patterns on a superiorly pedicled caudal TRAM flap during conditions of venous and arterial insufficiency, and determines whether cutaneous venous outflow can sustain a flap with venous insufficiency. Twenty-eight adult male Sprague-Dawley rats underwent superior pedicled TRAM flap elevation, and the zones were marked on the skin paddle. The animals were divided into four groups: control (group A, N = 6), arterial ligation (group B, N = 6), venous ligation (group C, N = 8), and venous ligation with cutaneous venous outflow (group D, N = 8). After 10 days, the skin paddle was photographed and the areas of necrotic skin were measured. Results showed that group B (selective arterial ligation) had 51.7 +/- 2.8% and 40.0 +/- 2.0% skin necrosis in zones I and II respectively. Zone I necrosis was significantly greater in group B compared with the control (p < 0.05). Group C (selective venous ligation) resulted in 73.8 +/- 16.4% and 93.8 +/- 33.4% skin necrosis in zones III and IV respectively. This necrosis was significantly greater compared with the control (p < 0.001). Group D rats' lateral skin necrosis compared significantly less with group C (p < 0.001). These results demonstrate that the patterns of flap necrosis in rat TRAM flaps with poor arterial inflow differ from those with venous stasis. Necrosis of the contralateral portion (zone IV) of human TRAM flaps may be related to problems with venous stasis; thus, a cutaneous venous outflow may prevent this problem.     

膨体聚四氟乙烯补片修复胆管缺损的实验研究

目的 探讨膨体聚四氟乙烯（ePTFE)修复胆管缺损的可能性。方法 36条重庆地区成年犬,通过切除部分胆管壁（A组,14条）、整段切除2－4cm胆总管（B组,10条）和完全结扎胆总管（C组,5条;D组,7条）的方式建立胆管损伤模型,分别采用ePTFE补片修补胆管缺损,管形材料替代胆管,间置材料在胆囊、十二脂肠或空肠吻合修复胆管。观察动物在手术前后的活动状况,结合胆道造影了解胆通畅情况,并在术后3天,2、4、8、12及52周切取胆管修复处的组织,观察胆管组织的变化,不同手术方式对肝脏形态结构的影响。结果 A组采用ePTFE补片修补胆管,胆管上皮能覆盖材料表面,通畅率达75％（9／12）,胆汁引流通畅,肝脏无损害;B组通畅率为40％（4／10）,伴有不同程度的肝脏形态结构改变;C组和D组的材料均被排除,形成胆囊十二指肠或胆囊空肠瘘。结论 ePTFE补片具有操作简便、通畅率高的特点,可作为修补胆管缺损的材料。     

异体气管移植去抗原性的实验研究

目的探讨移植段气管去除上皮细胞和腺体细胞后异体、异位移植排斥反应的强弱。方法25只雄性SD大鼠作为供体,制备新鲜移植段气管、冷冻移植段气管和去上皮细胞移植段气管。取制备的新鲜移植段气管40个平均分为4组,分别用0、0.1、0.3和0.5mg/ml的蛋白酶溶液,4℃浸泡12h,根据镜下移植段气管上皮细胞和腺体细胞脱落情况及软骨细胞破坏程度确定蛋白酶的最佳浓度。另取30只雄性SD大鼠作受体,均分成3组,分别为:新鲜气管移植组(A组)、冷冻气管移植组(B组)及去上皮细胞移植组(C组),n=10。行左上腹旁正中切口,提出大网膜包绕各移植段气管,于21d后取出移植段气管,行组织学观察及淋巴细胞浸润测定。结果0.3mg/ml蛋白酶能去除移植段气管上皮细胞及腺体细胞,而对软骨细胞无明显损坏。异体植入大鼠腹腔的3组气管软骨均成活,血运建立,其中A组管腔内有肉芽组织,出现坏死、实变;B组有少量肉芽组织;C组管腔内无肉芽组织。A、B、C3组淋巴细胞浸润分别为29.16±2.69、15.17±2.19和11.56±0.87个/Hp,A组与B、C组比较及B组与C组比较,差异均有统计学意义(P<0.05),排斥反应强弱为:A组>B组>C组。结论0.3mg/ml蛋白酶,4℃,浸泡12h的移植段气管,能完全脱上皮细胞和腺体,对软骨细胞基本无损伤,与冷冻法比较去抗原作用更好。一期异体大网膜包裹异位移植后,血运重建且移植段气管成活。     

Bile duct replacement using an autologous femoral vein graft: an experimental study. Preliminary results

The repair of common bile duct injuries is a complex procedure with a significant rate of postoperative morbidity and mortality. The aim of this study was to demonstrate the usefulness of the autologous vein graft in replacement of the bile duct. Twelve male Sprague-Dawley rats weighing 350 +- 550 g were used in the study and were divided at random into two groups: the control group (60) and the experimental group in which a 3-mm segment of the bile duct was resected and the biliary tract was replaced by a segment of vein aided by stent (G1). Both groups were subdivided into pairs of rats to study at 30, 60, and 120 days. All of the animals underwent radioisotope cholangiography, a repeat laparotomy, and blood tests for further pathologic study. The clinical evaluation and biochemical nuclear medicine and pathologic studies showed no evidence of cholestasis. The histologic study of the graft showed replacement of the endothelium by biliary-appearing epithelium. The use of an autologous vein graft with a supporting stent proves to be a feasible and alternative procedure for bile duct reconstruction. Further experimental studies should be carried out to validate these findings so they can be implemented in clinical cases.     

普通超声及超声造影检测兔胆道缺血模型胆道异常的可行性研究

目的探讨普通超声及超声造影应用于检测兔胆道缺血模型胆道异常的可行性。方法将20只健康新西兰兔随机分为两组,对照组及肝动脉和胆总管联合阻断2h(HBO2h)组(各10只)。HBO2h组用无损伤动脉夹阻断肝动脉及胆总管下段2h后去除动脉夹制作胆道缺血模型,对照组不进行任何手术处理。术后5d两组实验兔先后采用普通超声、超声造影观察胆总管-左叶胆管情况,然后处死动物取胆总管-左叶胆管标本行苏木素-伊红(HE)染色,对胆管组织缺血损伤程度进行评分,CD34免疫组织化学染色后行微血管密度(microvascular density,MVD)定量分析。结果普通超声表现:对照组门静脉管径/胆管管径比值为3.47±0.23,所有胆管(100%)均表现为管壁连续性好、无增厚,管腔清晰;HBO2h组胆管明显扩张,门静脉管径/胆管管径比值为1.25±0.42,与正常组比较差异有统计学意义(P<0.01);所有胆管均表现为管壁毛糙、增厚。超声造影表现:对照组所有胆管壁(100%)较肝实质提早增强,动脉期胆管壁呈细线状高增强,门静脉期及延迟期呈等增强;HBO2h组中60%(6/10)表现为动脉期胆管壁呈增强水平明显降低,门静脉期及延迟期呈低增强;40%(4/10)表现为增强扫描全过程均呈无增强;与对照组相比,HBO2h组各时相胆管壁增强表现差异均有统计学意义(均为P<0.05)。病理学表现:对照组胆管黏膜上皮细胞和黏膜下腺体上皮细胞呈柱状,排列紧密、完整,无上皮细胞变性、坏死、脱落等,胆管损伤评分为0分,MVD为(6.1±2.5)个。HBO2h组胆管壁增厚,胆管黏膜上皮细胞及黏膜下腺体上皮变性、坏死、脱落,管壁炎症细胞浸润,胆管损伤评分为(2.1±0.6)分,MVD为(2.2±1.6)个,与对照组比较差异有统计学意义(均为P<0.01)。结论普通超声及超声造影能较早发现胆道缺血兔模型的胆道异常,为缺血型胆道病变动物实验研究提供了一种简便、无创、动态监测病程发展的有效手段。     

Randomized comparison of percutaneous Viabahn stent grafts vs prosthetic femoral-popliteal bypass in the treatment of superficial femoral arterial occlusive disease

OBJECTIVE: This randomized prospective study was designed to compare the effectiveness of treating superficial femoral artery occlusive disease percutaneously with expanded polytetrafluoroethylene (ePTFE)/nitinol self-expanding stent grafts vs surgical femoral-to-above knee (AK) popliteal artery bypass with synthetic graft material. METHODS: From March 2004 to May 2005, 100 limbs in 86 patients with femoral-popliteal arterial occlusive disease were identified. Patients had symptoms ranging from claudication to rest pain, with or without tissue loss, and were prospectively randomized for treatment into one of two groups. The limbs were treated percutaneously with angioplasty and one or more self-expanding stent grafts (n = 50) or surgically with femoral-to-AK popliteal artery bypass using synthetic Dacron or ePTFE grafts (n = 50). The mean +/- SD total length of artery stented was 25.6 +/- 15 cm. Follow-up evaluation with ankle-brachial indices and color flow duplex sonography imaging were performed at 3, 6, 9, and 12 months after treatment. RESULTS: Patients were monitored for a median of 18 months. No statistical difference was found in the primary patency (P = .895) or secondary patency (P = .861) between the two treatment groups. Primary patency at 3, 6, 9, and 12 months of follow-up was 84%, 82%, 75.6%, and 73.5% for the stent graft group and 90%, 81.8%, 79.7%, and 74.2% for the femoral-popliteal surgical group. Thirteen patients in the stent graft group had 14 reinterventions, and 12 reinterventions occurred in the surgical group. This resulted in secondary patency rates of 83.9% for the stent graft group and 83.7% for the surgical group at the 12-month follow-up. CONCLUSIONS: Management of femoral-popliteal arterial occlusive disease using percutaneous treatment with a stent graft is comparable with surgical revascularization with conventional femoral-to-AK popliteal artery bypass using synthetic material up to 12 months. Longer-term follow-up would be helpful in determining ongoing efficacy.     

Microvascular repair following crush-avulsion type injury with vein grafts: effect of direct inhibitors of thrombin on patency rate

The aim of this study was to develop a standardized effective thrombogenic arterial anastomosis model, as usually encountered in clinical practice, and to offer a detailed evaluation of the antithrombotic effect of thrombin's direct inhibitors, antithrombin III and hirudin, as locally applied. Wistar rats were divided into four groups of 12 animals each. The carotid artery sustained a standardized crush-avulsion-type injury (groups B-D). A segment of the afflicted area was removed and replaced by a microvenous graft. Group A had no crush-avulsion injury inflicted; a microvenous graft replaced a simple resection from the center of the carotid artery. During microvascular anastomoses, normal saline (groups A and B), recombinant hirudin (group C), or antithrombin III (group D) were locally applied. Bleeding times were recorded, and patency tests were performed 20 min, 48 h, and 1 week after blood flow reestablishment. All grafts were harvested and examined histologically. Patency tests, 1 week postrevascularization, demonstrated that this experimental crush-avulsion injury model ensured low patency in group B (25%), whereas group A, which had no injury inflicted, achieved a 100% patency rate. The local application of hirudin and antithrombin III significantly increased bleeding times as well as the patency rate (92% and 75%, respectively) compared to group B. These findings indicate the efficiency of the experimental model and the potential use of thrombin's direct inhibitors in microvascular surgery.     

大鼠肝移植小移植物模型的研究

目的 建立大鼠肝移植小移植物模型，探讨移植物体积对受体生存的影响。方法 48只雄性SD大鼠随机分为4组：70％肝切除组(A组)、全肝移植组(B组)、中等移植物组(C组)、小移植物组(D组)。观察各组大鼠生存率。于术后不同时间点，采取外周静脉血检测肝功能；行肝组织常规组织学及透射电镜检测。结果 D组第3天生存率为56％，显著低于A、B、C组(P＜0．01)；各时间点D组各生化指标均显著高于其他3组(P＜0．01)；A、C和D组肝脏组织学以肝细胞再生的表现为主，B组以淋巴细胞浸润为主。D组术后第3天光镜下和透射电镜检查可见分裂肝细胞；第21天移植肝体积已达正常水平。结论 大鼠肝移植小移植物模型供肝量应超过全肝重量的45％。影响小移植物成活的主要因素是缺血—再灌注损伤和手术技术。     

Inhibition of subintimal hyperplasia of autologous vein bypass grafts by nimodipine in rats: a placebo-controlled study.

An arterial bypass may be required for the management of neoplastic or cerebrovascular disease. When an arterial graft is not suitable, autologous vein grafts are the most commonly used conduits; however, as many as 20% of the vein grafts used in vascular surgery may occlude as a result of subintimal hyperplasia. Although the mechanism initiating subintimal hyperplasia remains unclear, it is known that subintimal hyperplasia is dependent upon smooth muscle cell proliferation and migration from the media to the intimal layer. The present study focused on the prevention of smooth muscle cell proliferation using a calcium antagonist. Forty rats received an autologous vein bypass graft from the jugular vein to reconstruct the abdominal aorta. They were randomly divided into two groups of 20 rats each. Animals in the treated group received a calcium antagonist (nimodipine), and those in the control group received a placebo. Nine months after grafting, the group receiving the calcium antagonist presented no or only slight sub intimal hyperplasia as compared with the placebo-treated group (P less than 0.001). These data suggest that a calcium antagonist could be used for the prevention of venous graft disease.