Evaluation of glutaraldehyde-tanned human umbilical cord vein as a vascular prosthesis for bypass to the popliteal, tibial, and peroneal arteries.

One hundred and thirty-one reconstructions to the popliteal (n = 80), tibial (n = 26), and peroneal (n = 25) arteries were performed using glutaraldehyde (GA)-tanned human umbilical cord veins. Cumulative patency rates to 20 months, calculated by the standard life-table method were 84.8%, 74.0%, and 49.6% for popliteal, tibial, and peroneal reconstructions, respectively. The latter included many of the early cases with extremely advanced obliterative atherosclerosis and gangrene. These results are equivalent and even superior to those obtained with saphenous veins, particularly when the cases are analyzed in distinct clinical and pathological categories. The quality of the runoff was the major determinant in obtaining long-term patency and limb function. The primary factor accounting for graft closure was progression of the atherosclerotic process in the distal circulation. No failures could be attributed directly to the graft. This clinical experience confirmed previous data showing the unique properties of the GA-tanned umbilical vein. It is anticipated that longer-term follow-up will continue to show the superior qualities of this new vascular substitute.

Clinical experience with modified human umbilical cord vein for arterial bypass.

Umbilical veins were removed from human cords, tanned with gluteraldehyde, and surrounded by a polyester fiber mesh. Arterial bypasses were performed with this material in eight persons with threatened limb loss and for whom no other graft material was available. The distal anastomoses were to the small vessels of the leg or to the popliteal artery below the knee. Limb salvage and function were obtained in five patients. Three of these also required early thrombectomy to obtain success. This complication may be related to the presence of gluteraldehyde oligomers and polymers of free aldehyde groups. Morphologic evaluation of the graft suggests that human umbilical cords are a potentially valuable source for vascular substitutes.

Influence of failed vascular bypass procedures on conversion of below-knee to above-knee amputation levels.

From 1975 to 1980, 79 major limb amputations were performed from a group of 552 lower extremity vascular reconstructions with glutaraldehyde-stabilized umbilical vein grafts. All amputations were performed in instances in which limb salvage had been the indication for the attempted bypass (n = 520)--an incidence of 15.2%. Twelve of 51 below-knee (BK) amputations were converted to above-knee (AK) levels (crude failure rate, 23.5%). The highest crude failure rate occurred after failed bypass to the popliteal artery (33.3%); the lowest occurred after failed tibial bypass (16.7%), and the peroneal arteries were intermediate (22.2%). In addition to these 12, 28 primary AK amputations were performed. Excluding nine cases judged to require AK amputations before the attempted vascular reconstruction, success/failure rates for the entire series and each of the reconstruction types were calculated. Success, defined as a healed BK stump, occurred least after failed popliteal bypass, 44.5%, compared to 71.4% and 53.8% for the tibial and peroneal groups, respectively. Thus, failure of a popliteal bypass was more apt to lead to an AK amputation (56.5%) than failure of a distal bypass. In fact, tibial bypass failure leading to an AK stump occurred at a frequency (28.6%) almost similar to that obtained by other investigators when no previous bypass had been performed. Comparative cumulative graft patency and limb salvage rate data confirm the value of reconstructive vascular surgery, particularly in the peroneal group where negativism with regard to its clinical usefulness persists. With improved case selectivity and surgical expertise, increasing limb salvage rates can be secured while minimizing the definite morbidity of conversion of BK to AK amputation with failed vascular bypass.

Distal arteriovenous fistula as an adjunct to maintaining arterial and graft patency for limb salvage.

Sixty-one distal arteriovenous fistulas (dAVFs) were constructed as adjuncts to tibial and peroneal vascular reconstructive procedures in 58 patients threatened with imminent limb loss. Specific indications for dAVF construction were absent or deficient pedal arches, usually associated with small, calcareous crural vessels. Conventional bypasses had been previously performed in 35 patients. Cumulative graft patency rates were 56%, 39%, and 18% at 6, 12, and 24 months, respectively. For the same intervals, the figures were 56%, 52%, and 52% (P less than 0.001 at 24 months) for nonAVF reconstructions (n = 49). The corresponding cumulative limb salvage rates were 62%, 52%, and 40% for the dAVF group and 78%, 72%, and 72% for the nonAVF group (P less than 0.05 at 24 months). The perioperative mortality rate was 7% (four of 61). Twenty-four amputations were required, of which 16 were below the knee and six despite patent grafts. There was no significant morbidity attributable directly to the dAVF. Cardiac output showed no deviations from normal values. Primary causes of early failure were infection (n = 4), absence of satisfactory veins (n = 6), and inappropriate case selection (n = 7). Intimal hyperplasia led to dAVF closure and graft failure in 13 patients. This study shows that dAVFs can maintain graft patency by diversion of the overload on a high-resistance vascular bed and, secondarily, by augmentation of inflow. Immediate survival of the limb still depends on the arterial runoff, as retrograde venous flow caused by venous valvular incompetence is a delayed development. Adjunctive dAVF is justified in selected cases where conventional bypass failure has occurred or is predictable by increased pedal vascular resistance.

Intravenous rupture of arteriosclerotic aneurysms of the abdominal aorta.

Intravenous rupture of abdominal aortic aneurysms occurs infrequently but should be considered with the coexistence of severe congestive failure, anasarca, and abdominal bruits. Six patients are presented with four survivors. In only two patients was the diagnosis considered preoperatively without angiography. Two were variants in that thrombus occluded the fistula, thereby negating findings usually manifested clinically. Diagnosis of this type can be made only during operation when copious venous bleeding ensues with evacuation of the aortic thrombus. Careful fluid management and prompt surgery are prerequisites to obtaining a successful outcome. Repair is accomplished easily by suturing the fistula from the aortic aspect, but care is required to avoid dislodgement of thrombus and atherosclerotic debris resulting in pulmonary embolism.

Patient selection and improved technical factors in small-vessel bypass procedures of the lower extremity.

Thirty-two small-vessel bypasses were constructed as limb-salvage procedures. The one month patency rate was 72 percent and the one year cumulative patency rate was 55 percent. Preoperative, intraoperative, and postoperative angiography was performed in most cases and the results correlated with the ultimate fate of the graft. Preoperative angiography is critical in determining the location of a suitable small vessel, including the peroneal artery, and the quality of the runoff. Intraoperative angiography is required to delineate correctable intraoperative defects usually appearing at the distal anastomotic area. Additionally, failure to demonstrate runoff or a pedal arch can help support a decision not to re-explore a graft should early closure occur. Postoperative angiography is essential to validate clinical success with graft patency and function. It also serves to discover potential graft defects that might otherwise lead to closure and potential limb loss. Selected cases of failed small-vessel bypass grafts may be salvaged by thrombectomy with or without graft revision. Small-vessel bypass is generally contraindicated if there is extensive tissue necrosis and infection extending into the proximal foot. In cases where the necrotizing infection is localized, particularly to the forefoot, then open drainage, debridement, or amputation should be performed together with small-vessel bypass. Finally, the risks indigenous to small-vessel bypass procedures demand optimal patient selection and exquisite operative technique.

Arteriovenous fistulas constructed with modified human umbilical cord vein graft.

Arteriovenous (AV) shunts were created using modified umbilical veins in baboons. The shunts consisted of veins removed from human umbilical cords tanned by either dialdehyde starch or glutaraldehyde 2% and surrounded with a polyester fiber mesh. Twelve fistulas were constructed employing the femoral or axillobrachial vessels. Six of the seven straight axillobrachial shunts remained patent for up to four months during the period of study. One of two loop fistulas and three femoral AV fistulas thrombosed because of kinking. There were no infections, mural disruptions, or aneurysm formations. Anglogram results and histologic studies confirmed the maintenance of graft function, morphologic appearance, and tolerance to repetitive punctures.

Routine intraoperative angiography. An essential adjunct in vascular surgery.

Intraoperative angiography was performed during a variety of 155 arterial reconstructive procedures including bypass, endarterectomy, embolectomy, thrombectomy, primary reconstruction, and angioplasty. In 27 or 17% of these cases, defects were identified that could be corrected. These included technical errors at the suture line, accumulation of platelet thrombus and atherosclerotic debris, or unrecognized lesions in the runoff. The likelihood of identifying such lesions is greatest in patients undergoing bypass surgery, particularly when the distal anastomosis involves one of the leg arteries. Routine use of intraoperative angiography as an adjunct to vascular surgery is justified and will help to obviate many early graft failures.

Remote hydraulic syringe actuator: its use to avoid radiation exposure during intraoperative arteriography.

A simple, inexpensive device consisting of a double hydraulic syringe system and a holding fixture was devised for intraoperative arteriography to avoid exposure of personnel to radiation. The procedure of intraoperative angiography has thus become safer, less time consuming, and more reliable in obtaining high-quality angiographic studies.

Continuous epidural anesthesia and postoperative epidural narcotics in vascular surgery.

A combination epidural technique using local anesthetics intraoperatively and morphine postoperatively is shown to offer many advantages. These benefits include inhibition of the surgical stress response, decreased cardiorespiratory depression, decreased blood loss, decreased intubation and pulmonary infection, decreased thromboembolism, decreased hyperglycemic and hypertensive response, nitrogen sparing, a stable resting metabolic rate, prevention of immunosuppression, simplification of cerebral status monitoring, and earlier ambulation and hospital discharge. The main disadvantage in patients undergoing vascular procedures is the risk of epidural hematoma. A review of the literature confirms the extreme rarity of this risk and, in view of the emerging benefits, argues for reconsideration of epidural technique in vascular patients. The addition of epidural morphine to this combined technique affords a postoperative pain-free continuum unmatched by any other method. This significantly decreased pain stress in cardiac patients increases safety and comfort. In conclusion, epidural anesthesia and postoperative epidural narcotics provide a safe and reliable method of management for patients undergoing vascular procedures.

Femoral tibial-peroneal bypass: the lateral approach and use of glutaraldehyde-tanned umbilical vein.

Access to the peroneal artery as well as to the anterior tibial artery can be accomplished by a lateral approach with fibular resection. The technic is described as well as the use of the glutaraldehyde-tanned human umbilical cord vein as a vascular prosthesis. The results using the latter have been extremely gratifying.

A simple guideline to facilitate axial alignment of vascular grafts.

The proper orientation of vascular prostheses is essential for successful performance of vascular reconstructions. To prevent axial rotation of grafts, particularly in long tunnels such as in the axillo-femoral or subsartorial position, vascular prostheses with a simple guideline incorporated within their fibers were employed. The advantages of these grafts are discussed.

Blood-flow augmentation of intermittent pneumatic compression systems used for prevention of deep vein thrombosis prior to surgery.

PURPOSE: To compare, using Duplex ultrasonography, different intermittent pneumatic compression (IPC) systems to augment venous blood flow for deep venous thrombosis (DVT) prevention during and after surgery and during periods of immobility. METHODS: This cross-over study randomly assigned 26 young, healthy, adult subjects, without history of DVT, hypertension, diabetes, stroke. vascular or cardiac pathologies, to an order of knee-high, foam, single-pulse IPC device and thigh-high, vinyl, sequential-pulse pneumatic compression systems. Prior to making the flow measurement, the girth of the calf and thigh and length of the leg of each subject were determined. The right leg was used in this evaluation. RESULTS: The average flow augmentation, which is a direct measure of the amount of femoral vein blood flow velocity increase over the base, was 107%+/-49% with the knee-high system, and 77%+/-35% with the thigh-high IPC system (P<0.002). Augmentation was higher for 62% of the subjects with knee-high IPC, and for 23% of the subjects with the thigh-high system. Overall, the blood was actively moving through the vein during the decompression phase. On occasion, the velocity during the decompression phase would fall to zero for short intervals with both systems, indicating complete emptying of the vessel. Variation in limb anatomy did not significantly affect blood-flow augmentation with the knee-high IPC, but augmentation decreased with increase in girth with the thigh-high IPC. CONCLUSIONS: The study indicates that the knee-high, foam, single-pulse IPC device produces a significantly higher venous blood-flow augmentation than the thigh-high, vinyl, sequential-pulse system.

Improved patient selection for enzymatic lysis of peripheral arterial and graft occlusions.

Intraarterial thrombolysis by remote intravenous or direct intraarterial infusion of streptokinase is possible. The latter may be more effective with a lesser potential for systemic hemorrhagic complications because of the smaller dose administered directly in the area. Fifty patients with prosthetic graft, embolic, and renal artery occlusions were evaluated. Embolic occlusion responded dramatically, particularly since lytic therapy was initiated at an early stage. Patients with severe ischemia or those with simple localized occlusion were best treated by surgical means. Successful thrombolysis was also obtained with renal artery occlusions combined with percutaneous transluminal angioplasty. The management of patients with prosthetic graft occlusion by lytic therapy is complex. Optimal results can be obtained in patients presenting with occluded grafts after the immediate postoperative period and in those in whom previous satisfactory runoff has been demonstrated. Failure of lysis in this group is associated with a high incidence of limb loss due to unreconstructable obliterative disease. Successful lysis of occluded prosthetic grafts will often require corrective angioplasty or surgical revision.

Total pancreatectomy with primary mesenteric vascular reconstruction.

Total pancreaticoduodenectomy with resection of the superior mesenteric artery and vein was performed in a sixty-two year old man with islet cell carcinoma of the pancreas. Arterial reconstruction was accomplished with an aortomesenteric interposition Dacron graft. The venous system was reanastomosed primarily, the infrapancreatic superior mesenteric vein to the portal vein in the hepatic hilum. This procedure, although it did not result in long-term survival, demonstrates the technical feasibility of wide regional resection for tumors of the pancreas impinging upon the mesenteric vasculature in the region of the neck and uncinate process.

Adjunctive arteriovenous fistula with tibial and peroneal reconstruction for limb salvage.

Arteriovenous fistulas were constructed as an adjunct to femoral peroneal and tibial bypasses in 13 patients threatened by imminent limb amputation. Previous attempts at conventional vascular reconstructive procedures had failed in nine patients. Deficient or absent pedal arches were noted in all patients, as were poor quality or small crural arteries. Graft patency was achieved in 11 cases and limb salvage in 10. There was no mortality. A steal phenomenon occurred in one patient and was successfully treated by secondary popliteal vein ligation. These preliminary results clearly indicate that an adjunctive arteriovenous fistula can maintain patency in a femoral tibial or peroneal bypass graft while preserving flow into the markedly diseased distal circulation.

Comparative efficacy of topical hemostatic agents in a rat kidney model.

The efficacies of four topical hemostatic agents were compared in a rat model employing a standardized renal injury. The materials used to effect hemostasis were oxidized cellulose, microfibrillar collagen powder, positively charged modified collagen, and single donor heterologous fibrin glue. Animals that were treated only with surgical gauze served as controls. Hemostasis was achieved by application of one of the topical hemostatic agents plus moderate digital pressure. The time necessary to achieve complete hemostasis was recorded for each animal. Control animals bled profusely and suffered an increased postoperative mortality rate compared with the experimental animals. Microscopic studies demonstrated progressive healing of the injuries with varying degrees of inflammation and scar formation. Fibrin glue was by far the most effective agent in controlling hemostasis. The collagen materials, though effective, required a longer time to control bleeding and did not differ statistically in their activity from one another.

Epidural anesthesia as an adjunct to retroperitoneal aortic surgery.

Recent developments in vascular surgery suggest that the retroperitoneal approach to the aorta and the use of epidural anesthesia for lower limb revascularization are associated with decreased morbidity and shorter hospital stays. By combining these principles, we sought to determine if retroperitoneal aortic surgery could be performed under epidural anesthesia and if this might be advantageous. Over a 16-month period, 57 patients underwent aortic surgery via the retroperitoneal (n = 33) or transperitoneal (n = 24) approach. In the former, epidural anesthesia was employed in 10 patients, general anesthesia in 3, and combined epidural anesthesia and general anesthesia in the remaining 20. In the transperitoneal group, general anesthesia was employed in 21 patients and combined epidural anesthesia and general anesthesia in 3. Both groups were similar in age and gender, but risk factors were predominant in the retroperitoneal group. With the exception of one death due to aspiration, there were no significant differences between the transperitoneal and retroperitoneal groups with respect to overall morbidity, pulmonary complications, and length of stay in the intensive care unit and hospital. Despite these findings, we favor the combination of epidural and general anesthesia for retroperitoneal aortic surgery. Morbidity was significantly decreased (p less than 0.05) in low-risk retroperitoneal patients when combined epidural anesthesia and general anesthesia were employed.

History of prosthetic grafts.

The evolution of vascular surgery during the past five decades has established what was once controversial to be mandate, what was never dreamed of as debatable, and the vast body of knowledge yet to be unraveled--but requiring clinical application--as currently controversial. Controversy results when dissimilar therapies yield comparable outcomes, despite having been reached by different pathways. Scientific methods to dissect the precise mechanisms of cause/effect, and not reliance on associations, are necessary to resolve controversies that may contribute to inappropriate conclusions. Much effort has been expended by vascular surgeons in the search for an ideal vascular conduit. This edition of Seminars explores the status, past, present, and future, of a variety of graft materials. Future modifications and availability of the "ideal graft" will evolve as challenges are met.

Biological vascular grafts.

Biological bypass graft material has been used as an alternative to autogenous vein since the first lower extremity revascularization procedures were performed. Both immunogenicity and biodegradation can contribute to the failure of these grafts and must be addressed. Cryopreservation at ultralow temperatures (-196 degrees C) after pretreatment with dimethylsulfoxide has been successful in preserving viable vein graft endothelium. Both rejection and deterioration of the cellular elements may contribute to the relatively high failure rates. The umbilical vein graft has become an effective alternative to autogenous material. The glutaraldehyde tanning procedure increases tensile strength, masks antigenicity, and sterilizes the tissue. Recent results with excellent 5-year patency (67%) and cumulative limb salvage (80%) confirm the utility of this graft.