Porcine model for vascular graft studies.

Models for the study of prosthetic vascular graft infection have been studied frequently in the dog and rabbit. We have developed a reproducible swine model to study this problem and its treatment. The cardiovascular system, healing characteristics, and the bloodstream clearance of bacteria in swine more closely resembles those of humans than do other animal models. The low cost and availability of the swine is an additional attractive aspect. One hundred fifty-six farm-bred pigs have undergone infrarenal aortic replacement with a 3-cm segment of 6-mm prosthetic graft over the past two years. Graft infection was produced by (1) direct inoculation of 10(6) Staphylococcus aureus at the time of the surgery or (2) intravenous infusion of bacteria (10(2)-10(6) organisms/mL) immediately after surgery. All animals were sacrificed 1 to 4 weeks later, depending on the study design. Cultures, histology, and electron microscopy were performed on each graft. Anesthetic complications were rare (2.5%). Postoperative complications leading to animal death decreased with increasing experience (11.5%), but included graft thrombosis, bleeding, sepsis, intussusception, and colonic ischemia. Wound infection was the most common cause of morbidity. The swine model is an attractive alternative to that of other animals for the study of prosthetic vascular graft infections. Further details of the operative technique and the comparison to the human and other animal models is discussed.     

Vascular prosthetic infection with Staphylococcus epidermidis: experimental study of pathogenesis and therapy

To determine whether a slime-producing strain of Staphylococcus epidermidis was capable of producing acute infection of a prosthetic vascular graft, 5 cm segments of knitted Dacron were implanted in the infrarenal aortic position of dogs in three groups of animals. These included a control group (no graft contamination), a contaminated group that received a graft soaked in an S. epidermidis solution (untreated group), and a contaminated group in which perioperative antibiotics (three doses of cefamandole, 100 mg/kg) were administered (prophylaxis group). In all the animals reexploration and graft removal were performed at 10 days, with replacement of the defect being achieved with a new uncontaminated graft. These animals underwent exploration a third time after an additional 10-day period. S. epidermidis was not grown from the control animals (n = 7) but was cultured in 44% of the prophylaxis group (n = 9) and 88% of the untreated group (n = 16) during at least one of the operative procedures (chi 2 = 15.859; p less than 0.001). The pathologic features of acute S. epidermidis infection were best seen in the untreated animals and included anastomotic disruption (56%), periaortic hematoma, and lymphadenopathy (94%). Microscopic examination of the aortic tissues revealed extensive infiltrates of leukocytes, macrophages, and foreign body giant cells with aortic necrosis. These features were less prominent in the prophylaxis animals. We conclude that S. epidermidis is capable of producing acute graft infection with perigraft inflammation and anastomotic disruption. The administration of perioperative antibiotics reduced but did not abolish these effects of bacterial contamination of prosthetic vascular grafts.     

介入导管技术在动静脉内瘘失功治疗中的应用

目的:探讨动静脉内瘘(AVF)失功后介入手术的治疗方法,评估其治疗效果及应用价值。方法:回顾性分析自2006年4月—2015年1月行介入手术治疗的20例自体AVF失功患者的临床资料。结果:20例患者中,16例经静脉端造影,4例经股动脉-主动脉-腋动脉路径造影;单纯吻合口狭窄4例,行球囊扩张后狭窄明显改善;吻合口狭窄伴血栓形成有5例,切开取栓后再行球囊扩张治疗;静脉端血栓形成3例,切开取栓后返血良好;静脉端狭窄合并血栓形成7例,行切开取栓后再行球囊扩张治疗;头静脉长段闭塞1例,改用人工血管行AVF术。术后全部患者经该血管通路恢复透析治疗,透析时流量均200 m L/min。共17例患者获得随访,平均随访时间13.2个月,12个月通畅率为47.1%。结论:介入导管技术在治疗AVF失功方面是安全、有效的。     

Automated distal coronary bypass with a novel magnetic coupler (MVP system)

OBJECTIVE: We sought to assess the feasibility of performing sutureless distal coronary artery bypass anastomoses with a novel magnetic coupling device. METHODS: From May 2000 to April 2001, single-vessel side-to-side coronary artery bypass grafting on a beating heart was performed in 39 domestic white pigs (35-60 kg) without the use of mechanical stabilization, shunts, or perfusion bridges. Animals were divided into 2 groups. Seventeen pigs underwent right internal thoracic artery to right coronary artery bypass grafting through a median sternotomy (group 1) with a novel magnetic vascular positioning system (MVP system; Ventrica, Inc, Fremont, Calif). Twenty-two pigs underwent left internal thoracic artery to left anterior descending artery grafting with the MVP anastomotic device through a left anterior minithoracotomy (group 2). This system consists of 2 pairs of elliptical magnetic implants and a deployment device. One pair of magnets forms the anastomotic docking port within the graft; the other pair forms an identical anastomotic docking port within the target vessel. The anastomosis is created when the 2 docking ports magnetically couple. Anastomotic patency was evaluated by means of angiography during the first postoperative week and at 1 month. Histologic studies were performed at different time points as late as 6 months. RESULTS: Right internal thoracic artery to right coronary artery anastomoses and left internal thoracic artery to left anterior descending artery anastomoses were successfully performed with the system in all animals. The self-adherent and self-aligning properties of the implants allowed for immediate and secure approximation of the arteries (total anastomotic time between 2-3 minutes). Anastomoses were constructed without a stabilization platform. Five nondevice-related deaths occurred postoperatively. One-week angiography, performed in 35 surviving animals, showed a patent graft and anastomosis in all cases. The patency rate at 1 month was 97% (33/34). Histologic studies as late as 6 months demonstrated neointimal coverage of the magnets without any significant luminal obstruction. Histology also confirmed the presence of viable tissue between magnets. CONCLUSION: The MVP anastomotic system uses magnetic force to create rapid and secure distal coronary artery anastomoses, which might facilitate minimally invasive and totally endoscopic coronary artery bypass surgery.     

One Hundred Pancreas Transplants Performed in a Brazilian Institution

After decades of controversy surrounding the therapeutic validity of pancreas transplantation, the procedure has become accepted as the preferred treatment for selected patients with type 1 diabetes mellitus. Between January 2001 and January 2008, 100 patients underwent pancreatic transplantation at our center: 88 simultaneous pancreas-kidney transplantation and 12 pancreas transplantations alone. Pancreas graft management of the exocrine drainage technique involved enteric drainage in 8 (all simultaneous pancreas-kidney) and the bladder in 92 cases. The recipient systemic venous system was used for the pancreas graft venous effluent in all cases. Our overall results have shown that the number of functioning pancreatic grafts was 64 of 100. Graft losses were: rejection (n = 8), venous thrombosis (n = 9), arterial thrombosis (n = 1), or surgical complications such as anastomotic leak (n = 3), perigraft infection (n = 10), pancreatitis of the graft (n = 5). Most cases of pancreatitis (80%) had preservation times exceeding 18 hours. Despite surgical and immunosuppressive complications, our impression was that pancreas transplantation was a highly effective therapy for diabetes mellitus. After 7 years of the program and 100 transplantations, we believe that there is a major role for transplantation in diabetes management.     

Vascular complications of renal transplantation

From January, 1963, to May, 1979, 600 renal transplants were performed at the Cleveland Clinic. There were 21 vascular complications in this series (3.5 per cent). Arterial complications included renal artery thrombosis in 5 patients, renal artery stenosis in 9 patients, and anastomotic hemorrhage in 2 patients. Venous complications included renal vein thrombosis in 2 patients and hemorrhage in 3 patients. Although vascular complications led directly to graft loss in 10 patients, only 1 resulted in patient death.     

Graft-preserving treatment for vascular graft infected with Staphylococcus aureus with antibiotic-releasing porous apatite ceramic in the rabbit

OBJECTIVE: This study was undertaken to investigate whether infection of a vascular graft with Staphylococcus aureus can be treated in situ by applying antibiotic-loaded porous apatite ceramic, in a rabbit model. METHODS: Teicoplanin (TEIC) was loaded onto a beta-tricalcium phosphate (TCP) block, a type of porous apatite ceramic. The activity of TEIC released from the antibiotic-loaded TCP block was examined in vivo. A vascular graft was patched onto the abdominal aorta in 24 rabbits, and S aureus was applied directly on it. Seven days postoperatively, each rabbit underwent repeat laparotomy, and retroperitoneal abscess around the prosthetic vascular patch was debrided. Animals were divided into four groups of 6 rabbits each. In group 1 only debridement was carried out. In groups 2 and 3, solution containing 40 or 60 mg of TEIC, respectively, was applied to the prosthetic vascular patch. In group 4, an antibiotic-loaded TCP block (63 +/- 6.6 mg of TEIC) was placed around the graft. Three weeks after the second operation, the graft, the tissue around it, and arterial blood were collected and cultured. RESULTS: TEIC activity was maintained for 28 days in vivo. In group 1, bacterial cultures of the prosthetic vascular graft and the tissue around it were positive in 5 animals and negative in 1 animal (infection rate, 83%). In both groups 2 and 3, cultures were positive in 3 animals and negative in 3 animals (infection rate, 50%). In group 4, cultures were negative in all animals (infection rate, 0%). Blood cultures were negative in all animals. Infection rate in group 4 was significantly lower than that in group 1 (P =.03), and was also lower than that in groups 2 and 3, but the difference was not significant. CONCLUSIONS: Use of slow-release antibiotic loaded onto a TCP block, along with debridement, may control infection in vascular grafts in situ, averting the necessity to remove the graft.     

The prevention and treatment of vascular graft infection with a Triclosan (Irgasan)-bonded Dacron graft: an experimental study in the pig.

Objectives: to evaluate the role of Triclosan (Irgasan(R)) in the prevention of prosthetic graft infection. Material and methods: fifty-one pigs were assigned randomly to six groups. Group I (graft) and II (graft and Triclosan) were control groups. Groups III (graft) and IV (grafts and Triclosan) were contaminated with 2 x 10(7)CFU/ml S. aureus. Groups V (graft) and VI (graft and Triclosan) were intraoperatively contaminated with 2 x 10(7)CFU/ml S. aureus and reoperated on after 7 days. Remaining animals were sacrificed on day 28. The end point of the investigation was vascular graft infection, defined as the bacteriological and/or histological proof of infection. Results in both control groups no vascular graft infections were detected in Groups I and II. All of the group III animals presented but none of the group IV developed a graft infection (p <0.02). All of the group V animals presented and 10 of 12 animals developed a graft infection. Conclusion: in this animal model Triclosan bonding appears effective in preventing prosthetic graft infection. However, the in situ replacement of Triclosan-protected grafts was not successful in the treatment of graft infection.     

An Unusual Late Complication of Axillobifemoral Bypass Graft: A Case Report

Axillobifemoral bypass is a well-established surgical procedure performed in conditions that preclude direct arterial reconstruction due to aortic sepsis, aortoenteric fistula, or other hostile abdominal pathology or prohibitive surgical risk. The choice of prosthetic graft used is either knitted Dacron(R) or polytetrafluoroethylene, with equally good results. Although externally supported grafts reportedly yielded improvement in primary patency compared to historical controls, no consensus exists as to which demonstrates superiority over the other despite several retrospective studies. Complications are usually limited to the perioperative period, although late anastomotic disruption, graft thrombosis, axillary thromboembolism, pseudoaneurysm formation due to seat belt trauma, and hemorrhage or graft rupture have all been described. In addition to the above complications responsible for graft failure, perigraft infection, intimal hyperplasia, poor distal runoff, anastomotic fibrosis, and comorbid conditions may contribute to graft failure. We describe an unusual late complication of an axillobifemoral bypass graft whereby an organized thrombus within the layers of the bypass graft led to luminal compromise and, hence, attenuation of flow and resultant "failing graft."     

Small intestinal submucosa for vascular reconstruction in the presence of gastrointestinal contamination

INTRODUCTION: Surgical options for vascular reconstruction in a contaminated field are limited and include prosthetic reconstruction or ligation with extra-anatomic bypass. With prosthetic insertion, rates of graft infection and failures (pseudoaneurysms and thrombosis) are high. In the emergent situations, extra-anatomic bypass is time-consuming and complex, and it produces marginal long-term results. Small intestinal submucosa (SIS) is a cell-free collagen matrix derived from porcine small intestine. Preliminary studies have demonstrated its ability to be remodeled into host tissue. In this study, we compared SIS to polytetrafluoroethylene (PTFE) as a vascular patch for arterial repair in the presence of massive gastrointestinal contamination to evaluate graft patency, incorporation, infection, and aneurysm formation. METHODS: Adult mongrel pigs underwent general anesthesia with Isoflurane and were then randomized to 1 of 3 groups: control, contamination (colon puncture with stool contamination of the pelvis), or shock + contamination (40% blood volume for 1 hour, then resuscitation with shed blood and crystalloid, plus contamination). All groups then underwent a left common iliac arteriotomy and further randomized to a 1 x 3-cm patch angioplasty with either SIS or PTFE. All received cefotetan for 24 hours. All animals were sacrificed between 2 and 4 weeks, and necropsy was performed. Grafts were cultured, and microscopic analysis with hematoxylin and eosin and trichrome was performed. Outcomes included pulse quality (normal or diminished) compared with opposite side, graft infection, and pseudoaneurysm; all were determined by a blinded investigator. RESULTS: Forty animals were randomized, and 1 died of abdominal sepsis. All control animals had normal distal pulses, no pseudoaneurysms, and no patch infections. The pseudoaneurysm rate for the contaminated PTFE patches was 25% compared with 0% in the SIS group (P = 0.09). Patch infection occurred in 73% of all PTFE patches compared with 8% of SIS patches (P < 0.03). Organisms present in the infected grafts included Escherichia coli, Bacteroides species, and other Gram-negative enterics. Histopathology demonstrated the presence of neointima in both SIS and PTFE. Only SIS was completely incorporated, with infiltration of collagen fibrils and lymphocytes. CONCLUSIONS: SIS was associated with improved graft patency, less infection, complete incorporation, and no false aneurysm formation when compared with PTFE. This may be due to its ability to provide a durable scaffold for cellularization and tissue remodeling. This material may offer a superior alternative to more complex vascular reconstruction techniques in contaminated fields.     

A Swine model for long-term evaluation of prosthetic heart valves

BACKGROUND: The objective of this study was to develop a porcine model of mitral valve replacement (MVR) for long-term evaluation of prosthetic heart valves. METHODS: Sixteen 25-kg male Bama miniature pigs underwent MVR using St Jude Medical valve (21 mm). Each animal was allocated to an anticoagulation protocol after surgery (group I, s.c. heparin injection and warfarin (n = 8); group II, s.c. low-molecular-weight heparin and warfarin (n = 8)) and was followed for up to 20 weeks. Terminal studies were carried out on all animals having survived for more than 140 days or died. RESULTS: Fourteen animals survived for more than 1 month without signs of heart failure. One of group I animals died from haemorrhagic (haemopericardium) complications on the 9th postoperative day, and another animal of group I died on the 18th postoperative day because of valve thrombosis. CONCLUSIONS: Compared with other species, humans and pigs show remarkable anatomical and physiological similarities. This model is promising for long-term preclinical evaluation of prosthetic heart valves and evaluation of postoperative anticoagulant agents.     

Use of superficial femoral vein in the treatment of infected aortoiliofemoral prosthetic grafts

PURPOSE: To assess the use of the superficial femoral vein for the reconstruction of the aortoiliofemoral sector in the treatment of prosthetic infections. METHODS: From December 1995 to November 1999, 12 patients with infection involving a synthetic vascular prosthesis were submitted to thirteen surgical procedures involving partial or total resection of a synthetic vascular prosthesis and restoration of arterial flow with an in situ femoral vein. RESULTS: The overall operative mortality rate was 15.3% (2 out of 3 patients who underwent total graft replacement and 0 out of 9 patients who underwent unilateral graft replacement). Major amputations related to the surgical procedures were performed in two cases (an 87.5% rate of limb salvage). The series was followed up on average for 22 months (range: 6-65 months). No patient presented clinically significant edema or signs of chronic venous insufficiency in the lower limbs used as donors of autogenous venous grafts. All surviving patients presented complete resolution of the infectious signs and symptoms and none of them presented late thrombosis of the venous graft. CONCLUSION: The use of the superficial femoral vein is a good surgical alternative for the treatment of prosthetic infections with minimal venous morbidity of the lower limbs used as venous graft donors. The autogenous venous grafts present good long-term patency and excellent adaptation to the aortoiliofemoral position.     

Surgical complications are the main cause of pancreatic allograft loss in pancreas-kidney transplant recipients

We examined surgical complications among a group of diabetic type 1 patients (IDDM) with end-stage renal disease (ESRD) who had undergone pancreas-kidney transplantations (PK). Between October 1993 and August 2004, 70 SPK were performed using bladder (n = 14) or enteric (n = 56) drainage. Donors were selected according to standard criteria (mean age, 27.6 years; range, 17-49). All patients received cyclosporine-based immunosuppression. All pancreata functioned immediately, whereas 2 patients needed postoperative dialysis. Four patients (5.7%) lost their pancreatic graft due to vascular thrombosis; both patients underwent urgent allograft pancreaectomy and pancreas retransplantation (re-PT). One of them (1.4%) experienced a venous thrombosis and died due to a pulmonary embolism at 12 hours after re-PT. The other 3 patients had uneventful postoperative courses and were discharged with good pancreatic and renal function. Three patients in the bladder group (21.4%) had an anastomotic leak, which resolved with a bladder catheter. Four patients in the enteric group (7.1%) who experienced an anastomotic leak needed a second surgical procedure but in 3 of them allograft pancreatectomy was necessary. Relaparotomy was required in the other 3 patients due to hemorrhage (1 patient) or occlusion (2 patients). Acute rejection episodes, which occurred in 16 patients (22.8%), were treated with steroid boluses. With a mean follow-up of 72 months (range, 3-129), 2 patients have died at 8 and at 36 months, respectively, after SPK due to acute myocardial infarction (2.9%). Chronic rejection was the leading cause of pancreatic failure in 5 patients (7.1%) and of renal failure in 2 patients (2.8%). Patient, kidney, and pancreas survival rates were 95.8%, 92.9%, and 81.5%, respectively. Surgical complications were the leading cause of pancreatic allograft loss in IDDM and ESRD patients submitted to SPK.     

Laser-Fused Biologic Vascular Graft Anastomoses

Tissue fusion using laser energy is a promising new technology that may improve the healing of anastomoses. This study evaluated the feasibility of using argon laser energy to fuse vascular tissue and biologic vascular prostheses (St. Jude Medical, Inc.) in a canine arteriovenous (A-V) fistula model. Five animals had 4-cm length, 3-mm internal diameter grafts (n;eq 10) placed bilaterally as side-to-side A-V interpositions from the femoral artery to femoral vein. One A-V graft was placed using argon laser energy with the vessel edges aligned by 6-0 polypropylene traction sutures at 3 to 4 mm intervals. The contralateral graft was sutured using running 6-0 polypropylene suture. Anastomoses were successfully fashioned in all animals except for episodes of delayed bleeding at two laser-fused segments (15 min and 2 hrs) and one segment in a suture control (6 days). The implants were removed to evaluate the integrity and healing of the anastomoses at 2 hrs, 8 days, and at 7, 9, and 11 weeks. In all instances, there was no evidence of anastomotic dehissance or enlargement. Histologic examination of the anastomoses revealed coapted vessel and prosthetic edges in laser-fused specimens and a limited foreign-body response to the permanent sutures in the suture controls. In the longer term specimens there was marked intimal proliferation at the venous anastomosis in all implants, with recent bilateral occlusions of the 7 and 11 week implants at the venous connection. We conclude that laser fusion of biologic vascular prostheses to autogenous vessel is possible with healing and no evidence of anastomotic dehissance. The technique may provide a method to limit development of anastomotic stenosis by eliminating the foreign body reaction. In addition, the canine arteriovenous model used in these experiments develops aggressive intimal lesions at the venous anastomosis within weeks and may be used to evaluate the effect of anastomotic technique on the development of this lesion.     

Monocytogenic endothelialization in dacron grafts. Experimental studies on rats

The cytogenetic relationship between cells of the hematopoetic system and prosthesis lining cells is still not known. The purpose of this experimental study was to determine to what degree blood monocytes may be transformed into those cells which line the inner surface of vascular grafts. Immunological identical rats (donors = 25) were pretreated with a total dose of 150 micrograms C 3H-thymidine. In 25 recipient rats of the same strain the infrarenal aorta had been replaced by a vascular graft of dacron (1.8 mm theta) by using microsurgical techniques. Arteriovenous cross-transfusion was installed in pairs of the donor and recipient animals allowing for mixing the total blood volumes of both many times. Following sacrifice of the recipients the grafts and the area of anastomosis were studied autoradiographically. In all animals labelled monocytes were found in the graft wall with a marking index (MI) running between 1.5% to 5.5%. The marking index of the prosthesis lining cells was 1.9% to 3.4%. In 6 animals the anastomotic area was labelled and the MI run from 1% to 7.5%. With this new experimental model we ascertained that blood monocytes have capability of transformation: our results would indicate the hematogenic origin of new endothelial cells on prosthetic vascular surface by transformation of blood monocytes. This appears to apply to the prosthetic wall as well as the inner surface lining cells and the neighbourhood of the anastomotic area.     

人造血管旁路术后移植物感染的外科治疗

为评价人造血管旁路术后移植物感染外科治疗的临床疗效,作者对１９８５年～１９９５年上海中山医院收诊的２５０例人造血管旁路术后发生移植物感染的８例进行分析。临床表现为移植物外露伴创口溢脓、大出血、移植物和／或远端肢体动脉搏动消失、远端肢体坏疽。移植物感染率３．２％。外科治疗包括：（１）移植物去除、清创引流术;（２）移植物去除、清创引流加截肢术;（３）移植物去除、清创引流加近远端动脉人造血管重建术;（４）单纯清创引流术。结果显示,８例中６例痊愈,２例因吻合口破裂出血死亡。作者认为移植物感染的危险因素有：（１）糖尿病;（２）继发血肿;（３）同一部位多次手术。外科积极处理较保守治疗愈后更好。     

Reoperations for late complications following abdominal aortic operation

Fifty patients were identified who, following abdominal aortic operation, developed late complications affecting the vascular graft or endarterectomy and who underwent their first reoperation between 1979 and 1989. Thrombosis was the commonest complication affecting 28 (56 per cent) patients, followed by false aneurysm in 11 (22 per cent), enteric fistula in nine (18 per cent) and graft infection in two (4 per cent). The 30-day mortality rate for reoperation was 8 per cent; longer follow-up revealed mortality rates of 22, 50 and 63 per cent at 1, 3 and 5 years respectively. Thirty-four complications required reoperation within 5 years of the original surgery. Reoperation was needed for 35 patients whose original pathology was occlusive disease and for 15 whose original pathology was aneurysm. The nature of the complication was related to initial pathology; thrombosis was far commoner in those with occlusive disease, and enteric fistula and false aneurysm were commoner in those with aneurysmal disease.     

A single‐centre experience of Roux‐en‐Y enteric drainage for pancreas transplantation

Exocrine drainage following pancreas transplantation can be achieved by drainage into the bladder or bowel, the latter typically by direct duodeno‐jejunostomy; the use of Roux‐en‐Y enteric drainage is uncommon. We report a retrospective analysis of a single‐centre experience of Roux‐en‐Y enteric drainage following pancreas transplantation. Over a 14‐year period (2001–2015), 204 consecutive adult pancreas transplants were performed (96.6% simultaneous pancreas and kidney transplants), of which 26.0% were from donors after circulatory death (DCD). During a median follow‐up of 67 months (range 13–183 months), 14 (6.9%) recipients experienced complications related to their enteric drainage. Complications during follow‐up included early enteric anastomotic haemorrhage (five patients), non‐anastomotic enteric bleeding (one patient), small bowel obstruction (four patients) and graft duodenal perforation (two within 6 weeks, five beyond 12 months). No recipient lost their graft as a direct result of complications related to enteric drainage. Patient and pancreas graft survival at 1 year was 99.0% and 94.0% and at 5 years 91.3% and 84.9%, respectively. We conclude that Roux‐en‐Y enteric drainage following pancreas transplantation is a safe and effective procedure and facilitates graft salvage in the event of graft duodenal perforation.     

Heparin-bonded expanded polytetrafluoroethylene grafts for infragenicular bypass in patients with critical limb ischemia: 2-year results

AIM: The use of prosthetic grafts in below-knee (BK) bypasses may be necessary in patients with no available autologous vein and critical limb ischemia not amenable to angioplasty. Such conduits, however, have generally yielded disappointing results. METHODS: A new heparin-bonded expanded polytetrafluoroethylene graft (Gore-Tex Propaten Vascular Graft) designed to provide resistance to thrombosis may be associated with decreased early graft failure and increased patency. This graft was implanted in 27 limbs (26 patients; 18 men; mean age 71 years; Rutherford class 4 to 6 disease) in a BK femoropopliteal and femorodistal location, without perioperative complications and with immediate graft patency. RESULTS: During a mean follow-up time of 24 months, 4 cases of thrombosis occurred, all at least 6 months postoperatively: 2 cases resolved after fibrinolytic treatment, 1 required surgical revision and in 1 case, amputation was required because of a delay in seeking treatment for thrombosis. Two patients died of cardiac disease during follow-up. The 2-year primary and secondary patency rates for the BK bypasses were 85% and 93%, respectively; the limb-salvage rate was 96%. CONCLUSION: These results are encouraging for a prosthetic graft, especially in the light of the severity of the vascular disease in the limbs treated.     

Reconstruction of the lower extremity with microvascular free flaps: a 10-year experience with 304 consecutive cases

A retrospective review of 304 consecutive microvascular free flaps to the lower extremity was done to identify the patterns of usage, results, and problems. The most common indication (91%) was for the replacement of extensive tissue loss caused by motor-vehicle injuries. Most of the defects were below the mid-tibia (73%). The associated compound fractures were predominantly gradable as Gustilo type IIIb&c. The latissimus dorsi, the rectus abdominus, and the scapular skin were the flaps used most commonly for coverage (77%). The overall flap failure rate was 8%, compared with 3% for our series of non-lower extremity cases, and 0% for the non-traumatic lower extremity cases. The magnitude of the traumatic insult was the most significant factor associated with anastomotic failure. The rate of anastomotic thrombosis doubled in the presence of vascular trauma, increased threefold in the presence of larger bony defects, and increased fivefold when vein grafts were needed. Experience was important in reducing the complications and improving the results. Fourteen patients (6%) underwent an amputation within the first 3 months, ten of them because of flap failure. Of 85 patients followed up for over one year, 91% had recovered good to excellent leg function. The ability to add healthy and well vascularized tissue to the traumatized limb is critical for the achievement of: 1) early definitive wound healing and restoration of function; 2) salvage of many impending amputations; 3) better prosthetic stump reconstructions; 4) better esthetic results.