Surgical experience with expanded polytetrafluoroethylene (PTFE) as a replacement graft for traumatized vessels.

With the increased nationwide incidence of major vascular injuries, the need for interposition grafting has become quite common in major trauma centers. Despite extensive experience with such injuries, the choice of a substitute conduit remains controversial. Recent studies have demonstrated the potential of expanded polytetrafluoroethylene (PTFE) as a replacement graft for small arteries and veins. The surgical services at the Ben Taub General Hospital began to use PTFE grafts in traumatic vascular wounds approximately 2 years ago. Eight axillary arteries and 12 brachial arteries have had interposition grafting with PTFE prostheses. Eleven patients have required PTFE interposition grafts in repair of traumatized common, superficial, and profunda femoris arteries and common femoral veins; eight patients had reconstruction in the popliteal artery or vein. Three patients had renal artery revascularization procedures following blunt abdominal trauma, three patient had segmental replacement of the superior mesenteric artery following gunshot wounds, and one carotid artery, one iliac vein, and two axillary veins were grafted with PTFE. All patients with segmental repair of axillary, brachial, femoral, and popliteal vessels have maintained good distal pulses and viable extremities. No grafts have thrombosed, nor become infected, in spite of soft-tissue injury encountered at time or repair. In situations requiring interposition graft placement for reestablishment of distal flow in small arteries and veins, PTFE grafts appear to be an acceptable prosthesis.     

Nontraditional sites for vascular anastomoses to enable kidney transplantation in patients with major systemic venous thromboses

Successful renal transplantation requires low‐pressure venous drainage to permit adequate outflow from the allograft. We report here a series of three patients in whom the inferior vena cava as well as bilateral iliac veins were thrombosed, making it necessary to explore less traditional vessels for venous drainage of the renal allograft. We utilized the splanchnic vasculature in two cases and the native left renal vein in another. The resulting atypical intra‐abdominal locations of these allografts also presented difficulties for arterial anastomoses and for urinary drainage. Arterial conduits were utilized in two cases to facilitate anastomosis to the common iliac artery or the aorta, and in the third case, the splenic artery was used for arterial inflow. A traditional ureterocystostomy was technically feasible for only one patient. In another, ureteroureterostomy to the native ureter was performed, and in the third case, the creation of an ileal conduit was necessary. All three patients had antibodies to human leukocyte antigens and two required desensitization. All three kidneys had immediate graft function and continued to function at 1 year post‐transplant. With a combination of planning, creativity, and persistence, patients with IVC thrombosis can enjoy the benefits of renal transplantation.     

The use of long synthetic microvascular grafts to vascularise free flaps in rabbits

A 5 cm length of 2 mm internal diameter (i.d.) synthetic, expanded polytetrafluoroethylene (PTFE, or Gore-Tex) vascular graft was used to connect 25 rabbit inferior epigastric flaps to the contralateral femoral vessels. In 15 animals an expanded PTFE graft connected the opposite femoral artery to the flap while the ipsilateral venous drainage remained intact. In the remaining 10 animals an expanded PTFE graft was used to replace the venous drainage of the flap and connected to the opposite femoral vein while the ipsilateral femoral artery supplied the flap. Flap survival and graft patency were evaluated over 3 weeks. Ten of 15 flaps with intra-arterial grafts survived at 3 weeks (67%). Only 27% (4/15) of their supplying grafts remained patent for 3 weeks, although 67% (10/15) were patent at 10 days. All 10 flaps, where expanded PTFE grafts replaced venous outflow, failed within 36 hours. At exploration these grafts were thrombosed or collapsed. In conclusion, currently available 2 mm (i.d.) expanded PTFE vascular graft cannot maintain patency in a low blood flow circulation supplying an isolated free flap.     

Is lymphocele in renal transplantation an avoidable complication?

BACKGROUND: This study evaluated the impact of surgery in the incidence of lymphocele after kidney transplantation (KTx). METHODS: A prospective randomized study was conducted during a 6-year period on a group of patients undergoing KTx and operated on by the same surgeon (CVS). A total of 280 patients undergoing KTx were randomly allocated into two groups: (1) group C (control group) was 140 patients who were submitted to KTx with standard technique: implantation of the kidney in the controlateral iliac fossa with vascular anastomoses on the external iliac vessels; and (2) group M (modified technique group) was 140 patients who underwent a modified technique with a cephalad implantation of the graft in the ipsilateral iliac fossa and vascular anastomoses in the common iliac vessels. Both groups were comparable for age, cold ischemia time, incidence of rejection episodes, presence of adult polycystic kidney disease, and source of donor graft. RESULTS: Group M showed an incidence of lymphocele production (3 patients, 2.1%) significantly lower than group C (12 patients, 8.5%). Eight patients (1 in group M and 7 in group C) required surgical treatment by peritoneal fenestration. No allograft or recipient was lost as a result of fluid collection but the hospitalization was shorter in group M than in group C. CONCLUSIONS: A cephalad implantation of the renal graft in the ipsilateral iliac fossa has been associated with a lower incidence of lymphocele, probably because vascular anastomoses on the common iliac vessels cause less lymphatic derangement than those performed on the external iliac vessels.     

Renal vessel reconstruction in kidney transplantation using a polytetrafluoroethylene (PTFE) vascular graft.

BACKGROUND: We report a rare experience in reconstructing short renal vessels in kidney transplantation using polytetrafluroethylene (PTFE) vascular grafts. METHODS: The short renal vessels in three kidney grafts were managed by the interposition of PTFE vascular grafts. Two grafts were from deceased donors and the third was a renal auto-transplant graft. RESULTS: PTFE grafts were used to lengthen short renal veins in two kidney grafts and a short renal artery in one. The warm ischaemia time was under 1 h and all kidneys functioned well post-operatively. Excellent blood perfusion in the three renal grafts was present on postoperative MAG 3 renal scan. No intra-operative or post-operative complications were encountered. CONCLUSIONS: In the three described patients, the use of PTFE vascular graft presented no additional morbidity to the kidney transplant operation and no post-oerative complication was related to its use. However, more data are necessary to conclude that PTFE graft can be used safely in kidney transplantation.     

Inferior vena cava bypass: experimental evaluation of externally supported grafts and initial clinical application

Inferior vena caval obstruction is an unusual but important clinical problem for which adequate treatment previously has not been available. Recently, a polytetrafluoroethylene (PTFE) graft with external rigid spiral supports was developed that appeared particularly applicable to the venous system. In 18 dogs a 15 cm length of Impraflex was placed from the proximal right common iliac vein to the inferior vena cava (IVC) at the level of the renal veins after IVC and right iliac vein interruption. End-to-end and end-to-side iliac vein anastomoses were alternated, with and without distal femoral arteriovenous (AV) fistulas (AVFs). At 2 months, with a distal AV fistula, 11 of 12 (92%) grafts were patent, angiograms demonstrated no evidence of intraluminal clot, and there was no hind limb edema. Following AVF ligation 2 months after graft insertion, 10 grafts remained patent, but five developed some intraluminal thrombus and one of them progressed to complete occlusion. Four months after fistula ligation (6 months after graft insertion) 9 of 12 grafts (75%) remained patent. All six grafts without distal AVF were occluded within 1 week. This procedure was performed on one severely symptomatic patient who had IVC occlusion, and currently the patient shows marked improvement. Thus IVC bypass is possible when an externally supported PTFE prosthesis is complemented by a temporary AVF.     

Successful renal transplantation in high-risk small children with a completely thrombosed inferior vena cava

BACKGROUND: Inferior vena cava (IVC) thrombosis is generally a contraindication to renal transplantation in small children because of the technical difficulty and limitations in allograft venous outflow drainage that risk graft thrombosis. METHODS: The records of six consecutive children (9.9-27.4 kg) with end-stage renal disease and thrombosed IVCs were reviewed. Small deceased donor renal allografts were utilized in all cases where immediate posttransplant venous renal outflow would theoretically not exceed the drainage capacity of the iliac or adjacent pelvic collateral veins. RESULTS: There is 100% patient survival with two patients returning to dialysis at seven and three years posttransplantation. There were no surgical complications or delayed graft function. Postoperatively, progressive renal vein and simultaneous iliac venous enlargement was observed in five of six recipients concomitant with renal allograft enlargement. In these patients, maximum renal volume achieved was between 152 and 275 ml and last recorded Schwartz glomerular filtration rates ranged from 67 to 118 ml/min. The sixth allograft had an early, severe rejection episode that limited renal growth and attainment of good renal function. All patients demonstrated resumption of growth rates commensurate with age but without significant catch-up growth. CONCLUSION: A small deceased donor kidney can provide freedom from dialysis and better quality of life for small children with IVC thrombosis during an age when dialysis treatment is difficult and the complications of the thrombosed IVC may compromise life. Good renal function was attained in patients without rejection episodes. In those with rejection, our approach allowed for patient growth during allograft function, providing a bridge for a repeat transplant.     

Renal transplantation with iliac vein transposition

We evaluated a technique for implantation of right kidneys with short renal veins without the need for venous reconstruction. METHOD: The technique of iliac vein transposition was performed in six recipients who received right kidneys with short renal veins. Two cases were living related donors, two were living unrelated, one was an autotransplant, and one was a cadaver kidney recipient. The common and external iliac veins and arteries of the recipient were thoroughly mobilized, allowing for the lateral transposition of the external iliac vein with respect to the external iliac artery. The renal vessels were subsequently implanted in an end to side fashion onto the corresponding transposed external iliac vessels. After implantation, the iliac vein remained lateral with respect to the iliac artery. CONCLUSIONS: The technique described allows for the implantation of right kidneys without the need for venous reconstruction. Such an approach is especially useful in cases of grafts with short veins.     

Freshly harvested cadaveric venous homografts as arterial conduits in infected fields

Six patients with patent multilevel prosthetic grafts (three axillofemoral-femoral grafts, an aortobifemoral graft, an axillofemoral and femoral-anterior tibial graft, and an axillofemoral and femoral-popliteal graft) that demonstrated overt infection involving both the proximal inflow (one infrarenal aorta, five axillary arteries) and groin anastomoses required complete graft excision. Cadaveric inferior vena cava, common and external iliac, common and superficial femoral, and greater saphenous veins were harvested in conjunction with multiple organ donor procedures. Identical anatomic reconstruction within the infected fields was accomplished, with patency and distal perfusion maintained for intervals sufficient to achieve complete resolution of infection in all cases. This interval of revascularization with a venous homograft has served as a temporizing maneuver, which permitted eradication of infection and allowed subsequent reimplantation of prosthetic graft material without associated reinfection in the two instances in which it was required. Use of freshly harvested large-caliber caval, iliac, and femoral homograft veins as arterial substitutes in infected fields has not been previously reported. Case histories and a review of the venous homografting literature are included.     

Early failure of expanded polytetrafluoroethylene in femoral vein replacement.

Grafts of expanded 30-mu fibril length polytetrafluoroethylene (PTFE) were inserted as segmental femoral vein replacements in nine dogs. The contralateral femoral vein served as a control, receiving a graft from each dog's right external jugular vein. Graft patency was monitored for 24 weeks postoperatively with serial venograms and venous pressures of the operated limbs. All expanded PTFE grafts and one autogenous graft thrombosed within 24 to 48 hours. Significant venous hypertension in the extremities receiving the PTFE grafts persisted for six months.     

Aortic reconstruction in patients with functioning renal allografts

Patients with functioning renal allografts requiring aortic reconstruction pose a considerable challenge to the vascular surgeon. A variety of strategies for renal allograft preservation during intervention have been described including hypothermia, indwelling shunts, cold renal perfusion, axillofemoral bypass, and endovascular stent-grafting. Reported here are two cases of successful aortic reconstruction utilizing standard open surgical techniques designed simply to minimize warm renal ischemia. The first case was that of a 55 year-old patient with a functional renal allograft originating from the right external iliac artery, who presented acutely with large symptomatic aortic and bilateral iliac artery aneurysms. He was treated with aorto-right femoral/left iliac bypass grafting. The right femoral anastomosis was performed first so that warm renal ischemia was limited to the 34 min required to perform the proximal end-to-end aortic anastomosis. The second case was that of a 44-year-old patient also with a transplanted kidney originating from the right external iliac artery. He presented with worsening hypertension, decreasing renal function, claudication, and severe aortoiliac occlusive disease. He was treated with aorto-left femoral bypass grafting via a retroperitoneal approach, followed by femorofemoral crossover bypass for retrograde perfusion of the kidney (total warm ischemia time 20 min). Both patients recovered uneventfully without a decrement in renal function and remain well on follow-up. It is concluded that standard open surgery without adjunctive shunts or bypasses remains a viable treatment option for these patients, provided warm renal ischemia can be minimized.     

Axillary to common iliac arteriovenous graft for hemodialysis access: Case report and review of 'exotic' axillary-based grafts

A 58-year-old Caucasian male with end-stage renal disease and peripheral arterial disease was referred to us for management of his complex vascular access. His vascular access history included a left wrist primary fistula, a left upper arm access graft, a left leg loop graft, and multiple PermCaths in his jugular veins with recurrent infections. Magnetic resonance venography (MRV) of his chest revealed extensive bilateral venous occlusions due to numerous past hemodialysis access catheters. The patient was scheduled for right lower extremity arteriovenous graft placement, but intraoperatively was found to have severe peripheral arterial disease and a thromboendarterectomy was performed instead. Lower body venous imaging demonstrated patent iliac veins. Based on these anatomic considerations a right axillary artery to right common iliac vein polytetrafluoroethylene (PTFE) graft was placed. The graft required revision twice--once for graft ultrafiltration at the arterial end of the graft and once for needle stick infection--but continues to serve as sufficient access after 15 months. Grafts based off the axillary artery have become increasingly popular in recent years and several venous outflow options have been considered, each with distinct advantages. The common iliac vein offers a central location with high flow rate and low probability of infection. Axillary artery to iliac vein arteriovenous grafting may have a place in the vascular surgeon's armamentarium for complex vascular access cases.     

Seatbelt injury resulting in functional loss of a transplanted kidney

The transplanted kidney, lying heterotopically in the iliac fossa, is especially vulnerable to damage from blunt trauma, particularly compression by vehicle seatbelt. We present a case wherein a functioning renal allograft lying in the right iliac fossa was severely injured by seatbelt compression, resulting in significant functional compromise and eventual loss. The patient later underwent successful retransplantation with a second living donor kidney. Management of injured renal transplant recipients requires appreciation of mechanisms likely to cause damage to the graft, as well as familiarity with available treatment options, both surgical and nonsurgical. As functional life spans of renal allografts improve, this type of injury will most likely be encountered with increasing frequency.     

血栓闭塞性脉管炎合并动脉硬化闭塞导致下肢缺血的手术治疗

目的 探讨下肢血栓闭塞性脉管炎(thmmboangiitis obliterans,TAO)合并动脉硬化闭塞症(arteriosclerosis obliterans,ASO)手术治疗效果.方法 回顾性分析2007年治疗的TAO合并ASO 6例患者的资料.2例行腹主动脉切开取栓+内膜剥脱+腹主动脉-股深动脉人工血管旁路移植-胭动脉人工血管-小腿动脉自体大隐静脉旁路移植术,1例行腹主动脉切开取栓+内膜剥脱+腹主动脉-右股深动脉人工血管旁路移植-膝下胭动脉人工血管旁路移植术;1例行左髂总动脉-左股深动脉人工血管旁路移植一胫前动脉自体大隐静脉原位移植术,1例行左侧人工血管切开取栓+左股深动脉成形-膝下腘动脉人工血管旁路移植术,1例行右股总动脉-左股总动脉人工血管旁路移植-胫后动脉自体大隐静脉旁路移植术.结果 5例患者术后恢复顺利,1例于术后当天出现股动脉-腘动脉人工血管和远段的大隐静脉桥血栓形成,立即再次手术行人工血管和大隐静脉切开取栓术,并同时行胫后动静脉吻合.6例患者均痊愈出院,无死亡病例.5例患者的下肢远端静息痛完全缓解,1例部分缓解.足部溃疡的2例创面明显缩小,无感染发生.所有患者得到随访,平均随访为6.5个月,3例足部溃疡愈合.1例术后3个月出现左股部切口感染,最终行膝上截肢处理,残端一期愈合.其他5例患者的移植血管通畅,症状缓解.结论 对TAO合并ASO患者如果手术治疗方式恰当,可以取得比较好的疗效.     

Das arterioarterielle Interponat als Dialysezugang

We report on two patients who received arterio-arterial PTFE grafts as vascular access for chronic hemodialysis. In both patients prior surgery for arteriovenous fistulas using either subcutaneous veins or arteriovenous, artificial PTFE grafts had failed due to recurrent thrombosis and septic complications. The arterio-arterial grafts were each positioned as a subcutaneous loop on the thigh and anastomosed with the common femoral artery and the superficial femoral artery or the profunda femoris, respectively. Postoperatively, both patients received coumadine for anticoagulation. Nine months after surgery no complications were observed in the former patient. The latter patient experienced recurrent thrombotic occlusion of the graft and a new graft was required which was anastomosed end-by-end onto the common femoral artery. As yet, 5 months after the second operation, no further complications have been reported. In conclusion, in patients lacking suitable veins for arterio-venous anastomoses, artificial arterio-arterial grafts may provide vascular access for chronic hemodialysis.     

Coating with paclitaxel improves graft survival in a porcine model of haemodialysis graft stenosis.

BACKGROUND: Most commonly resulting from intimal hyperplasia at the venous anastomosis, stenosis leading to thrombosis is a major cause of failure of polytetrafluoroethylene (PTFE) dialysis grafts. We recently reported that coating haemodialysis grafts with paclitaxel could reduce neointimal hyperplasia. This study tested whether paclitaxel-coating could prolong graft survival in a porcine model. METHODS: PTFE grafts were double-coated with paclitaxel. Bilateral grafts were created between the carotid arteries and the external jugular veins, and we evaluated graft survival by weekly measurements of blood flow for 12 weeks. RESULTS: We successfully implanted four pairs of paclitaxel-coated grafts and four pairs of control grafts in eight Landrace pigs. One control pig had to be euthanized at 4 weeks after graft placement. The grafts in the other three controls and four paclitaxel pigs survived until harvesting of the grafts. All paclitaxel-coated grafts remained patent for 12 weeks without decrease of blood flow. Median blood flow was 702 ml/min at three weeks and 818 ml/min at 12 weeks after placement. In contrast, the four control grafts lost luminal patency at 5, 6, 6 and 8 weeks, respectively. In Kaplan-Meier analysis, paclitaxel-coated grafts showed better survival than uncoated grafts (P = 0.011). CONCLUSIONS: Double-coating with paclitaxel improved graft survival. Coated PTFE grafts may be effective for the prevention of graft failure in patients on haemodialysis.     

Catheter-directed therapy for DVT after pancreas transplantation

INTRODUCTION: Iliac vein deep venous thrombosis (DVT) ipsilateral to the pancreas transplant can lead to severe leg edema and compromise graft function. Treatment modalities for iliac vein DVT in the pancreas transplant recipient are limited. METHODS: Medical records of patients receiving pancreas transplants at a single center from November 1989 to July 2003 were reviewed retrospectively, identifying patients with iliac vein DVT. There were 287 pancreas transplants performed during this time. Pancreas transplantation in all recipients was performed in the right iliac fossa with the arterial supply consisting of a donor iliac artery Y interposition graft. Systemic venous drainage was to the iliac vein. Exocrine drainage was enteric or to the bladder. RESULTS: Four (1.4%) cases of iliac DVT were identified. All patients manifested lower extremity edema ipsilateral to the pancreas transplant. DVT was detected by ultrasound on days 4, 5, 13, and 60 post-transplant. In all cases, the iliac vein caudad to the pancreatic venous anastomosis was noted to be stenotic. Management involved balloon dilatation and endovascular stent placement in one patient, thrombolysis with tissue plasma antigen (t-PA) followed by stent placement in one patient, and percutaneous mechanical thrombectomy in two patients. All patients had improvement in leg edema and two patients continue to have good pancreatic allograft function. CONCLUSIONS: Iliac DVT is a rare complication of pancreas transplantation that usually develops in an area of stenosis caudad to the pancreatic venous anastomosis. Catheter-based treatment modalities with use of endovascular stents for treatment of underlying stenoses can serve as an adjunct in treating these complications.     

Limb salvage in lower-extremity sarcomas and technical details about vascular reconstruction

Vascular surgery may allow limb salvage when a sarcoma of the lower limb involves the main vascular bundle. We present our experience and describe the techniques which have been employed for such surgery. From October 1995 to April 1999, vascular surgery procedures were employed in seven patients with sarcomas of the thigh: two complete subadventitia dissections of the main vascular trunks, four artery replacements (two polytetrafluoroethylene [PTFE] grafts and two autologous saphenous grafts), and five venous reconstructions (all with autogenous saphenous graft: three substitutions; two distal transpositions with one external rigid support at the anastomosis). Clinical and instrumental (sonogram, computed tomography [CT] scan, echodoppler) follow-up was carried out at 3, 6, and then every 12 months after surgery (mean, 25 months; range, 6–53 months). Operative mortality and morbidity were nil. All the grafts were patent (one arterial thrombosis was successfully treated on the first postoperative day). The functional result was good in six patients and fair in one. Two patients died, 24 and 13 months after surgery, with disseminated disease, but had no local recurrence. Five patients are alive and disease-free. Vascular techniques allow limb salvage with en-bloc resection of sarcomas of the thigh involving the main vessels. Venous reconstructions are indicated after removal of both the superficial and deep femoral veins. We suggest limiting the number of anastomoses (two transpositions in our series) and using external rigid support in those patients with a small saphenous vein graft (one patient in our series). Received: February 7, 2000 / Accepted: July 21, 2000     

Venous reconstruction of the inferior vena cava bifurcation for retroperitoneal rhabdomyosarcoma in a child. Case report

Retroperitoneal tumors, as well as traumatic lesions and occlusions of the bifurcation of the inferior vena cava (IVC) and the common iliac veins may require venous vascular reconstruction. We present a method for inferior vena caval bifurcation reconstruction which employs the advantages of a large size straight expanded polytetrafluorethylene (ePTFE) graft in this position after a new IVC bifurcation has been created by uniting the stumps of both common iliac veins, and construction of an arteriovenous (A-V) fistula with controlled flow to decrease the rethrombosis rate of the graft, and still not cause heart failure. This method was used in a case of recurrent rhabdomyosarcoma in an 8 year old child encroaching upon the bifurcation of the IVC as well as on both common iliac veins. The situation was managed by radical resection of the tumor and by creating a new caval bifurcation of the common iliac veins, followed by interposition of a straight ePTFE graft. An A-V fistula was created between the left femoral vein and left femoral artery using the left greater saphenous vein in controlled fashion. The arterial defect of the right common iliac artery was reconstructed by interposition of a PTFE graft end-to-end.     

Usability of ringed polytetrafluoroethylene grafts for middle hepatic vein reconstruction during living donor liver transplantation

Large vein allografts are suitable for middle hepatic vein (MHV) reconstruction, but their supply is often limited. Although polytetrafluoroethylene (PTFE) grafts are unlimitedly available, their long-term patency is relatively poor. We intended to enhance the clinical usability of PTFE grafts for MHV reconstruction during living donor liver transplantation (LDLT). Two sequential studies were performed. First, PTFE grafts were implanted as inferior vena cava replacements into dogs. Second, in a 1-year prospective clinical trial of 262 adults undergoing LDLT with a modified right lobe, MHV reconstruction with PTFE grafts was compared with other types of reconstruction, and the outcomes were evaluated. In the animal study, PTFE grafts induced strong inflammatory reactions and luminal thrombus formation, but the endothelial lining was well developed. In the clinical study, the reconstruction techniques were revised to make a composite PTFE graft with an artery patch on the basis of the results of the animal study. MHVs were reconstructed with cryopreserved iliac veins (n = 122), iliac arteries (n = 43), aortas (n = 13), and PTFE (n = 84), and these reconstructions yielded 6-month patency rates of 75.3%, 35.2%, 92.3%, and 76.6%, respectively. The overall 6-month patency rates for the iliac vein and PTFE grafts were similar (P = 0.92), but the 6-month patency rates with vein segment 5 were 51.0% and 34.7%, respectively (P = 0.001). The overall graft and patient survival rates did not differ among these 4 groups. In conclusion, ringed PTFE grafts combined with small vessel patches showed high patency rates comparable to those of iliac vein grafts; thus, they can be used for MHV reconstruction when other sizable vessel allografts are not available.