Homologous Vein Research Articles

Usability of cryopreserved homologous great saphenous vein for hepatobiliary-pancreatic surgery and living donor liver transplantation

Usability of cryopreserved homologous great saphenous vein for hepatobiliary-pancreatic surgery and living donor liver transplantation

Portal vein wedge resection and patch venoplasty using autologous and homologous vein grafts during surgery for hepatobiliary malignancies.

Obtaining tumor-free resection margins is one of the most important factors for achieving favorable prognosis of patients undergoing resection for hepatobiliary malignancies. In this study, we present our experience of portal vein (PV) wedge resection and patch venoplasty using autologous or homologous vessel grafts for resecting perihilar cholangiocarcinoma, hepatocellular carcinoma, and distal bile duct cancer. Case 1 was 68-year-old male patient with type IV perihilar cholangiocarcinoma who underwent central bisectionectomy with caudate lobectomy and bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 14 months after surgery. Case 2 was 77-year-old male patient with type IIIA perihilar cholangiocarcinoma who underwent left medial sectionectomy with caudate lobectomy, bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 17 months after surgery. Case 3 was 54-year-old male patient with hepatitis B virus-associated liver cirrhosis and hepatocellular carcinoma with PV tumor thrombus who underwent left hepatectomy. The PV wall defect was repaired with an autologous greater saphenous vein patch. This patient survived 11 months after surgery. Case 4 was 65-year-old female patient with distal bile duct cancer who underwent pylorus-preserving pancreaticoduodenectomy, and main PV wedge resection and patch venoplasty with a cryopreserved iliac artery allograft patch. This patient survived 21 months after surgery. In conclusion, PV wedge resection and patch venoplasty can be used to facilitate complete tumor resection in patients undergoing various extents of surgical resection for hepatobiliary malignancies.

Portal vein wedge resection and patch venoplasty using autologous and homologous vein grafts during surgery for hepatobiliary malignancies

Obtainment of tumor-free resection margins is one of the most important factors for favorable prognosis of patients undergoing resection for hepatobiliary malignancies. In this study, we present our experience of portal vein (PV) wedge resection and patch venoplasty using autologous or homologous vessel grafts used in resection for perihilar cholangiocarcinoma, hepatocellular carcinoma and distal bile duct cancer. Case 1: A 68-year-old male patient with type IV perihilar cholangiocarcinoma underwent central bisectionectomy with caudate lobectomy and bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 14 months after surgery. Case 2: A 77-year-old male patient with type IIIA perihilar cholangiocarcinoma underwent left medial sectionectomy with caudate lobectomy and bile duct resection, and PV wedge resection and patch venoplasty with a cryopreserved iliac vein allograft patch. This patient survived 16 months after surgery. Case 3: A 54-year-old male patient with hepatitis B virus-associated liver cirrhosis and hepatocellular carcinoma with PV tumor thrombus underwent left hepatectomy. The PV wall defect was repaired with an autologous greater saphenous vein patch. This patient survived 11 months after surgery. Case 4: A 65-year-old female patient with distal bile duct cancer underwent pylorus-preserving pancreaticoduodenectomy and main PV wedge resection and patch venoplasty with a cryopreserved iliac artery allograft patch. This patient survived 21 months after surgery. In conclusion, PV wedge resection and patch venoplasty provide a useful option to facilitate complete tumor resection in patients undergoing various extents of surgical resection for hepatobiliary malignancies.

The wing venation of a new fossil species, reconstructed using geometric morphometrics, adds to the rare fossil record of Triassic Gondwanian Odonata

Probably the most common rock-imprint fossil-insect remain is an incomplete isolated wing. This pitfall has been traditionally addressed by manually reconstructing missing parts, which is not ideal to comprehend long-term evolutionary trends in the group, in particular for morphological diversity (i.e., disparity) approaches. Herein we describe a new Triassic relative of dragon- and damselflies (Odonata), Moltenophlebia lindae gen. et sp. nov., from the Molteno Formation (Karoo Basin, South Africa), on the basis of three incomplete, isolated wings. In order to provide a reconstruction of the complete wing venation of the species, we formalized and applied a repeatable method aiming at inferring the missing parts of a given specimen. It is based on homologous veins automatically identified thanks to a standardized color-coding. The dedicated script can be applied broadly to the fossil record of insect wings. The species is identified as a member of the Zygophlebiida, within the Triadophlebiomorpha. This discovery, therefore, represents the first ascertained occurrence of the latter group in Gondwana, an area where the fossil record of Odonata is depauperate.

Patency of Hemashield grafts versus ringed Gore-Tex grafts in middle hepatic vein reconstruction for living donor liver transplantation.

Backgrounds/AimsOwing to the short supply of homologous vein allografts, we previously used ringed Gore-Tex vascular grafts for middle hepatic vein (MHV) reconstruction in living donor liver transplantation. When ringed Gore-Tex grafts became unavailable, we used Hemashield vascular grafts. This study aimed to compare the patency and complication rates of Hemashield and ringed Gore-Tex grafts.MethodsThis retrospective two-arm study compared the study group that received Hemashield grafts (n=157) and the propensity score-matched control group that received ringed Gore-Tex grafts (n=157).ResultsIn the Hemashield and Gore-Tex groups, the recipient age was 54.7±9.4 and 53.3±6.3 years; Model for End-stage Liver Disease scores were 15.9±9.2 and 16.9±8.3; and graft-recipient weight ratios were 1.07±0.24 and 1.10±0.23, respectively. In the Hemashield group, V5 reconstruction was performed using single (n=113, 72.0%), double (n=39, 24.8%), and triple (n=3, 1.9%) anastomoses. The proportion of double and triple anastomoses for V5 and V8 was higher in the Hemashield group than in the Gore-Tex group. Two (1.3%) patients required MHV conduit stenting owing to early thrombosis of the Hemashield graft. There was no difference in conduit occlusion- free patient survival rates between groups (p=0.91). The incidence of accidental conduit migration in the Hemashield and Gore-Tex groups was 0 (0%) and 2 (1.3%), respectively.ConclusionsHemashield grafts used in MHV reconstruction demonstrated acceptably high short- and mid-term patency rates, no incidences of conduit migration, easy handling, and good flexibility for length adjustment. Therefore, we suggest that the Hemashield graft is the preferentially suitable prosthetic material for MHV reconstruction.

Limb salvage after aneurysmal degeneration of a cryopreserved vein allograft: Searching the autologous veins of the arm is worth the effort

We hereby report a case of limb salvage involving a 64-year-old man who was hospitalized with ischemic foot ulcers for two months. Endarterectomy with patching and stenting of the left iliofemoral artery failed. A composite bypass of two segments of the endarterectomized superficial femoral artery and a cryopreserved saphenous vein graft was implanted one week later. On day 4 postoperatively, an infection (Staphylococcus epidermidis and Pseudomonas aeruginosa) was treated empirically with antibiotics. Four months later, the femoro-tibial bypass thrombosed and the patency was restored by thrombolysis. The aneurysmal cryopreserved vein was excised. Iterative complications followed and final success was attained after implantation of autologous cephalic and basilic veins. Four years later, this femoro-tibial is still patent. After a gross observation, the explant was dissected and the most significant sections were processed for histology, followed by analyses in scanning electron microscopy, light microscopy and transmission electron microscopy. The explanted specimen showed a smooth flow surface proximally but a severe distortion distally, with an accumulation of poorly organized mural thrombi. The wall of the arterialized vein was accompanied with an important inflammatory reaction. The degradation of the collagen structure was evidenced in TEM. The fibrils of collagen were still individualized but were fragmented and did not display parallelly. The regular banding was preserved. The presence of Pseudomonas aeruginosa was shown inside the wall of the homologous vein. In case of sepsis, the most aggressive antibiotic treatments cannot fully eliminate the bacteremic colonizations within the wall of an alternative conduit. The cephalic and basilic autologous veins are proved to be preferable in absence of the autologous saphenous vein. The amputation was prevented and four years later the bypass is still patent. This is an outstanding result based upon the comorbidities of the patient. The most aggressive harvesting shall be recommended. This patient represented a considerable challenge and the clinical result is highly gratifying: the search for the autologous cephalic and basilic veins proved to be worth the effort.

Long-term patency and complications of ringed polytetrafluoroethylene grafts used for middle hepatic vein reconstruction in living-donor liver transplantation.

BackgroundHomologous vein allografts are adequate for reconstruction of the middle hepatic vein (MHV) in living-donor liver transplantation (LDLT). However, supply is a matter of concern. To replace homologous vein allografts, polytetrafluoroethylene (PTFE) grafts were used. This study aimed to assess the long-term patency rates and complications of PTFE grafts used for MHV reconstruction of LDLT in a high-volume liver transplantation center.MethodsWe analyzed the patency rates of PTFE-interposed MHV in 100 LDLT recipients and reviewed complications including PTFE graft migration.ResultsThe mean age was 53.5±5.4 years and male to female ratio was 73:27. Primary diagnoses were hepatitis B virus infection (n=71) and other (n=28). Mean model for end-stage liver disease score was 16.2±8.3. V5 reconstruction was performed as either single anastomosis (n=85) or double anastomoses (n=14). No V5 reconstruction was required in one patient. V8 reconstruction was performed as single anastomosis, double anastomoses, and no reconstruction in 75, 0, and 25 patients, respectively. During a mean follow-up of 6 years, three recipients required early MHV stenting within 2 weeks. After 3 months, there were no episodes of congestion-associated infarct, regardless of MHV patency. Patency rates of PTFE-interposed MHV were 54.0%, 37.0%, and 37.0% at 1, 3, and 5 years, respectively. Unwanted PTFE graft migration occurred in two recipients, and the actual incidence was 2% at 5 years.ConclusionsPTFE grafts combined with small-artery patches demonstrated acceptably high short- and long-term patency rates. Since the risk of unwanted migration of PTFE graft is not negligibly low, lifelong surveillance is necessary to detect unexpected rare complications.

Safety and efficacy of venous reconstruction in liver resection using cryopreserved homologous veins.

Only a few studies have reported the resection and reconstruction of major hepatic veins during hepatectomy. Here, we present our strategy and techniques for venous reconstruction with cryopreserved homologous veins, and describe the surgical outcome. Among 2,387 hepatectomy patients, 39 patients who required hepatic venous reconstruction were reviewed retrospectively. Venous reconstruction was performed to secure a non-congested liver remnant volume of at least 40% of the total liver volume. There was no operative mortality, and the severe morbidity rate was 5% in this series. A total of 41 veins were reconstructed; 30 with homologous veins (73.2%) and 11 with autologous veins (26.8%), with the middle hepatic vein being the most frequent (n=23, 56%). Interposition grafting was performed more often (P=0.003), the length of the venous resection was longer (P=0.007), and pathologic wall infiltration of the vein was revealed more often (P=0.002) in the homologous graft group than in the autologous graft group. The 1-, 2-, and 3-year overall patency of the reconstructed veins was 55.4%, 46.3%, and 46.3%, respectively. Aggressive venous reconstruction during hepatectomy using cryopreserved homologous veins is a feasible option with satisfactory short-term outcomes, and may be warranted to improve operative safety.

Outflow Reconstruction Using Cryopreserved Homologous Venous Grafts in Living Donor Liver Transplantation

ObjectivesThe techniques and outcomes of outflow reconstruction in living donor liver transplantation (LDLT) using cryopreserved homologous veins at the University of Tokyo Hospital are presented. MethodsWe performed 540 LDLTs from January 1996 to March 2015. Graft types included right liver graft (n = 262), left liver graft (n = 196), left lateral sector graft (n = 53), and posterior sector graft (n = 28). We routinely use cryopreserved homologous vein grafts for the hepatic vein reconstructions to secure the large outflow of the graft. In addition to the presentation of our techniques, the cases with symptomatic outflow obstruction and the treatments were also investigated. ResultsThe 1-, 3-, and 5-year graft survival rates were 90.6%, 86.1%, and 83.5%, respectively. The incidence of severe complications (Clavien-Dindo grade IIIb and more) was 38%. The overall incidence of outflow obstruction requiring invasive treatment was 1.9% (10/540), including 3 left liver grafts (1.5%, 3/196) and 7 right liver grafts (2.7%, 7/262). Regarding the patency of the reconstructed veins, the left hepatic vein, middle hepatic vein, and right hepatic vein achieved nearly 100% patency. On the contrary, venous tributaries such as V5, V8, and inferior right hepatic vein were frequently occluded in the postoperative course. ConclusionsOutflow reconstruction is a key for the successful LDLT. Cryopreserved homologous vein graft is useful for the promising hepatic vein reconstruction.

In Situ Procurement of a Recipient's Portal Vein for a Right Lobe Liver Graft With Multiple Venous Orifices: A Case Report

Reconstruction of multiple venous orifices of a right lobe graft is a time-consuming and troublesome procedure in right lobe living-donor liver transplantation. In the current study, we present a new venous reconstruction technique for a right lobe graft with multiple and complex hepatic vein (HV) orifices, in which procurement of the recipient's left portal vein was performed in situ to keep the anhepatic period to a minimum. All of the HV orifices were reconstructed together at the back table, while maintaining patency of the recipient's systemic and splanchnic circulation. A homologous vein graft and veno-venous bypass were not necessary. All HVs were patent during the follow-up and the patient was free from complications. In conclusion, the present technique is readily available for reconstruction of complex and multiple HV tributaries, while avoiding a long anhepatic time and the use of veno-venous bypass.

Safety and efficacy of cryopreserved homologous veins for venous reconstruction in pancreatoduodenectomy

There are several techniques for reconstructing the portal vein-superior mesenteric veinduring pancreatoduodenectomy. The aim of the present study was to present our results with portalvein-superior mesenteric vein reconstruction using cryopreserved homologous veins during pancreatoduodenectomy for patients with pancreatic head cancer. Patients who underwent pancreatoduodenectomy for pancreatic head cancer were reviewed retrospectively. In patients with portal vein-superior mesenteric vein resection, the detailed method of reconstruction and clinical outcomes were reviewed. Clinical characteristics, patient survival, and portal vein-superior mesenteric vein patency were compared between those with and without homologous vein grafts. Factors affecting the patency of reconstructed veins were assessed by univariate analysis. Among 144 patients undergoing pancreatoduodenectomy, portal vein-superior mesenteric vein resection was performed in 36 patients (25%); 18 (50%) underwent reconstruction with homologous veins, and the other 18 (50%) underwent reconstruction without homologous veins. The extent of portal vein-superior mesenteric vein involvement, operative time, duration of clamping of portal vein-superior mesenteric vein, intraoperative blood loss, and length of the venous resection were greater (P≤.013 each) in those with homologous vein grafts. There was no significant difference in postoperative morbidity/mortality, patient survival, or portal vein-superior mesenteric vein patency. The 1- and 2-year overall patency of portal vein-superior mesenteric vein was 76% and 71%, respectively, while the 2-year patencies were 67% and 67% in those with homologous veins and 87% and 73% in those without homologous veins without difference between the groups. Circumferential resection and pathologic portal vein-superior mesenteric vein involvement were associated with the patency of the reconstructed vein (P=.002 and P=.028, resp). Use of homologous venous grafts for portal vein-superior mesenteric vein reconstruction are feasible alternatives during pancreatoduodenectomy for advanced pancreatic head cancer.

Reconstruction of hepatic venous tributary in right liver living donor liver transplantation: The importance of the inferior right hepatic vein.

Special care must be taken in hepatic vein reconstruction to avoid outflow block in living donor liver transplantation (LDLT) with a right liver graft. We have used cryopreserved homologous veins to reconstruct the right hepatic vein (RHV), middle hepatic vein (MHV), MHV tributaries (V5 and V8), and inferior right hepatic vein (IRHV). The reconstruction of V5, V8, and IRHV was based on the estimated congestive volume, calculated by the computed tomography volumetry, to secure the functional graft volume of 40% of the recipient standard liver volume. Among 262 right liver LDLT recipients, the number of reconstructed RHVs, MHVs, V5s, V8s, and IRHVs was 262, 48, 110, 111, and 147, respectively, and the overall patency was 95%, 100%, 36%, 58%, and 86%, respectively. Although the patency of the RHVs and MHVs was satisfactory, that of the V5s, V8s, and IRHVs was suboptimal. Patency of the IRHVs (86%, 126/147) was significantly better than that of both V5s (36%, 40/110) and V8s (58%, 64/111; P < 0.001). In addition, the estimated volume drained by IRHVs was significantly greater than that of V5s and V8s (IRHV, 176 ± 92 mL; V5, 105 ± 49 mL; V8, 127 ± 60 mL; P < 0.001). The patency of IRHV was significantly improved by applying the double inferior vena cava method (93%, 94/101) when compared to the direct anastomosis to vena cava (68%, 25/37; P < 0.001). The IRHV functioned as a main drainage route in cases of an obstructed RHV. In conclusion, reconstruction of the IRHV is recommended, not only to improve the functional reserve of the graft, but also to secure multiple drainage routes of the graft.

Adult Right Living-Donor Liver Transplantation With Special Reference to Reconstruction of the Middle Hepatic Vein

Two hundred fifty-three consecutive living-donor liver transplant recipients with a right liver graft (RLG) were divided into three groups: an extended right liver graft (ERLG) group (n = 47) in which the middle hepatic vein (MHV) trunk was included in the graft, a modified right liver graft (MRLG) group (n = 114) in which the MHV tributaries were reconstructed with cryopreserved homologous veins and a simple RLG group (n = 92) in which the MHV tributaries were sacrificed. The volume of the anterior sector was significantly impaired in the RLG group compared to the other two groups, whereas the volume of the posterior sector was significantly improved in the RLG group, indicating that the impaired anterior sector regeneration by MHV deprivation was compensated by the posterior sector regeneration. The regeneration rate of the anterior sector was highest in the ERLG group (92%), moderate in the MRLG group (71%) and lowest in the RLG group (52%). The whole graft regeneration rate of the ERLG group was significantly higher than that of the other two groups. Poor regeneration, however, was not correlated with delayed functional recovery or long-term outcome. Short-term, the patency of reconstructed MHV tributaries was over 90%, but occlusion occurred frequently over the long-term, especially in V5.

A Step toward Nonrobotic Total Endoscopic Coronary Bypass Grafting: 40 Coronary Anastomoses in a Biomechanical Beating Heart Model

Nonrobotic total endoscopic coronary bypass grafting is commonly considered as technically too difficult. After endoscopic practicing in a simple box model, we questioned this statement in a more sophisticated training model. In a handmade chest model containing a mechanically actuated porcine heart, anastomoses between homologous vein and shunted anterior coronary artery were performed using Prolene 7-0 sutures or U-clips in 20 anastomoses each. Commercially available endoscopic instruments and exclusive two-dimensional endoscopic vision were used. As quality control, the procedures were recorded, flow was measured, indocyanine green dye angiograms were performed, vinylpolysiloxane endocasts were produced, and finally the anastomoses were assessed from the endothelial side. Three-dimensional computed tomographic reconstruction was explored for cast measuring. All anastomoses were completed successfully in a time of 51 ± 14 minutes (Prolene) and 48 ± 10 minutes (U-clips). Despite suboptimal equipment, a reproducible sequence of the procedure was established and documented. Improving surgical performance was reflected in a reduction in anastomotic leakage and time requirement. The quality assessment protocol showed a learning curve and problems itself, which are briefly discussed. A beating heart model is an adamant requirement of training for the technically demanding procedure of nonrobotic total endoscopic coronary bypass grafting. Refinement of the model and quality assessment as well as expansion of training to other regions of the heart should prepare for a cost-effective, broad-based clinical application of nonrobotic endoscopic techniques in coronary surgery. Available high-definition three-dimensional vision systems and the development of appropriate (articulating) instruments will make the procedure safer and quicker and will cut the learning curve.

Lower limb ischemia after migration of a coronary artery stent into the femoral artery

A coronary stent may be lost in the peripheral or visceral arterial system with an incidence ranging from 0.9 to 8.4%, however, a limb or organ ischemia after stent migration is very uncommon. We report the case of an 83-year-old man who underwent coronary artery stenting at our Hospital's Cardiological Department. During this difficult procedure, due to the critical stenosis of the circumflex artery, the stent was accidentally lost and found at the level of the insertion of the right common femoral on the external iliac artery. After several attempts to rescue the stent through an omolateral and contralateral femoral approach with the hook technique, the right common, superficial and profunda femoral arteries were surgically exposed. The stent was easily removed from the origin of the profunda femoral artery by a longitudinal arteriotomy. Finally, the arteriotomy was closed with a homologous saphenous vein patch. We underline the importance of an early extraction of the stent, discussing the preferable surgical approach to minimize the possible dramatic complications in the peripheral artery system.

Primary extraanatomical revascularization for groin infections in drug addicts

Arterial groin infections in drug addicts are associated with a risk of amputation and are potentially lethal. Primary revascularization with an obturator bypass represents a potential alternative to local revision and arterial ligation alone. We report our experience with this approach. From January 1999 until December 2005 twelve drug addicts were treated due to arterial infections in the groin. In eight patients (seven men, one woman, 31 years old on average), the defect in the artery could not be repaired and ligation of the femoral vessels led to critical ischemia. Therefore, an iliaco-popliteal bypass via the foramen obturatorium was implanted either primarily or secondarily. In three patients a cryopreserved homologous vein was used, five patients received alloplastic grafts. Four of eight obturator bypasses were implanted primarily. In the other four patients the initial treatment was limited to local debridement and artery ligation and an obturator bypass was implanted at a later date. Two grafts occluded within the first 30 days. Thereof one was successful thrombectomized. The other patient had no critical ischemia and he refused further surgery. Three more grafts occluded at 74, 90 and 103 days after surgery. No patient demonstrated signs of graft infection and all groin incisions healed uneventfully. A lower limb amputation became necessary in one patient even though the reconstruction was patent due to embolisation of mycotic material. All patients remained drug dependent throughout the followup time which was 3 months on average and ranged from one to 40 months. The patency of obturator bypasses was 75% at one month. This appears low, especially if one considers the youthful age of the patients and the absence of arterial occlusive disease. Nevertheless, the amputation rate also remained low. Therefore, we feel that this technique may contribute to limb salvage in groin infections in drug addicts.

Pseudo-aneurisma de artéria tibial posterior pós-tratamento de fratura de perna com fixador externo: relato de caso e revisão da literatura

Este trabalho descreve um caso de pseudo-aneurisma da artéria tibial posterior devido ao uso de fixador externo para tratamento de fratura dos ossos da perna (técnica de Ilizarov), bem como as técnicas utilizadas para seu tratamento. A compressão guiada por ultra-som e a injeção de trombina guiada por ultra-som foram realizadas, sem sucesso. O tratamento definitivo do pseudo-aneurisma e reconstrução arterial foi conseguido através do tratamento cirúrgico clássico, usando enxerto interposto de veia safena magna homóloga invertida. As indicações, vantagens e desvantagens das técnicas de tratamento não invasivo (compressão guiada por ultra-som e injeção de trombina guiada por ultra-som) e as possíveis causas de sua incapacidade na obliteração do pseudo-aneurisma são discutidas. Também foi realizada a revisão de casos de pseudo-aneurisma da artéria tibial posterior na literatura médica, encontrando-se apenas um caso semelhante, entre 24 publicados.

Portal Vein Interposition Using Homologous Iliac Vein Graft during Extensive Resection for Hilar Bile Duct Cancer

Although autologous vein grafts have been used for portal vein (PV) reconstruction after long-segment portal vein resection during surgery for hilar bile duct cancer, their procurement prolongs operation time and increases morbidity. Less is known regarding the use of homologous vein grafts. The feasibility of homografts for PV reconstruction was preliminarily evaluated in two patients who underwent curative resection for hilar cholangiocarcinoma. Both patients underwent left lobectomy, caudate lobectomy, bile duct resection, and segmental PV resection and interposition vein graft reconstruction. The iliac vein homografts were obtained from deceased organ donors and stored for 1–2 days in cold preservation solution without freezing. Neither immunosuppression nor anticoagulation was attempted. One patient has shown good PV patency for 27 months. The second patient, who had received adjuvant chemoradiotherapy, showed an asymptomatic waisting at the proximal PV anastomosis site after 4 months, which was relieved by percutaneous balloon dilatation, and has been doing well for 12 months. In conclusion, our preliminary experience with these two patients suggests that cold-stored iliac vein homografts can be considered as PV substitutes after long PV segment resection during extensive hepatobiliary surgery.

Blood flow study of arteriovenous grafts with homologous and autologous veins in canine femoral vessels

The objective of this study was to assess the blood flow in arteriovenous (AV) communications comparing autologous and homologous veins, in the femoral vessels of dogs. Ten mongrel dogs were used for the blood flow analysis, and two AV grafts (AVG) were placed in each of them. The grafts were made with an autologous vein in one side, and a omologous vein, kept in a 0.25% glutaraldehyde solution, in the other side. The volumetric flow was measured before and after AVG placement. Fifteen minutes after surgery, the volumetric flow was measured in the cranial artery, in the caudal artery, in the graft and in the vein, and the same procedure was repeated 15 days after surgery. Measurements were done using an eletromagnetic flowmeter calibrated previously. For data analysis, the Wilcoxon test was used (to compare the difference in the results between the times and the techniques used) alfa </=0.05). An increase of about 5.3 times was observed in the femoral artery cranial portion flow of these accesses during the first operation and an increase of 6.8 times in the re-operation for both techniques. In the femoral artery caudal portion of the AVGs there was a blood flow inversion of about 1.6 times for both techniques during the first operation and about 4.1 and 3.7 times for the autologous and homologous veins, respectively. There was a significant increase in the autologous grafts. In the cranial portion of the femoral vein, there was an increase in the flow in relation to the femoral artery flow before graft placement. There was an increase of 5.3 and 7.4 times for the autologous and homologous grafts, respectively, in the first operation and from 8-9.6 times in the re-operation. There was also a significant increase in the autologous graft in relation to the two procedures. A significant difference among the grafts placed during the first surgery was observed, which was not observed after 15 days. In the graft blood flow analysis, a flow increase of 5.1 times for the autologous vein and 6.6 times for the homologous vein and from 7.5-8.2 times in the re-operation was found in relation to the femoral artery flow. There was a significant increase in autologous vein flow between the first operation and the re-operation. The mean blood flow of the homologous AVG was greater during the first operation and similar to the autologous grafts during the re-operation. Therefore, the homologous AVG could be considered a possible alternative to vascular access for hemodialysis.

Reconstruction for renal artery aneurysm: operative techniques and long-term results.

Ninety-four patients (37 male, 57 female; mean age, 51.0 years) underwent reconstruction for renal artery aneurysm (RAA) between 1980 and 2001. RAAs were present in 52 patients in the right kidney, in 29 patients in the left kidney, and in 13 patients in both kidneys. Eighty-three aneurysms were located in the mainstem, 49 in a branch artery, and four in an accessory artery. Additional ipsilateral renal artery stenoses (RAS) occurred in 26 patients, bilateral RAS in 18, and contralateral RAS in six. The causes of RAA were fibromuscular dysplasia (n = 48), atherosclerosis (n = 28), dissection (n = 7), aortic coarctation (n = 5), arteritis (n = 3), giant cell arteritis (n = 1), Marfan's syndrome (n = 1), and trauma (n = 1). Seventy-five patients had hypertension, 14 were asymptomatic, and five had rupture. Indications for RAA repair concerned aneurysms with 1 cm or more diameter in combination with risk factors of hypertension, ipsilateral and contralateral stenosis, and childbearing age in women. Without risk factors, aneurysm size eligible for reconstruction was limited to 2 cm or more. Methods applied for reconstruction in 107 kidneys and 136 aneurysms included aneurysm resection with tailoring (n = 37), saphenous vein graft interposition (n = 40), tailoring and saphenous vein graft interposition (n = 7), resection and reanastomosis (n = 14), saphenous vein graft interposition and resection and reanastomosis (n = 3), polytetrafluoroethylene bypass (n = 5), and homologous vein graft interposition (n = 1). Four reconstructions had to be performed ex situ because of multiple branch involvement in three patients and rupture in one. In all patients, the concerned kidney was protected with hypothermic flush perfusion with addition of heparin and prostaglandin E1. The overall morbidity rate was 17%, including one early graft occlusion, one partial thrombosis of the renal artery that necessitated fibrinolytic therapy, and a branch artery stenosis after tailoring managed with aortorenal bypass. The mortality in elective cases was null; one patient died of myocardial infarction 2 days after an emergency operation for ruptured RAA. The technical primary success rate was 96.8%; the secondary success rate was 98.9%. After a follow-up period from 1 to 143 months (mean, 46 months) in 83 patients (88%), 67 (81%) had patent renal arteries free of stenoses. Among six patients with RAS, four underwent successful reoperation, five had mainstem occlusions, three had segmental artery occlusions, and two underwent nephrectomy. Concerning the patients who underwent reoperation, percutaneous transluminal angioplasty was considered seriously but assessed as inappropriate because of long extension of stenosis or involvement of branch arteries. Hypertension was cured in 19 patients (25%) and improved in 17 (22%). Surgical reconstruction of RAA is a safe procedure that provides good long-term results, prevents aneurysm rupture, cures or improves hypertension in about half of the cases, and can be achieved with autogenous reconstruction in 96%.