Biodegradation and aneurysm formation in umbilical vein grafts. Observations and a realistic strategy.

In a series of 756 glutaraldehyde-stabilized umbilical vein grafts implanted over a 7 1/2-year period, aneurysms were identified in seven cases. The earliest aneurysm was seen at 31 months after implantation and the remainder between 43 and 79 months after surgery. Corrective surgery was performed in five cases and succeeded in four. Although definite mechanisms have not been identified, mechanical fatigue, reversal of aldehyde crosslinks, and immunologic factors may be operative. The pathologic changes include: (1) actual dilation of both graft and mesh with or without intraluminal thrombus and, (2) maintenance of graft diameter with erosion of the umbilical vein and polyester mesh rupture leading to perigraft hematoma and false aneurysm formation. Microscopic examination and infrared spectral analysis confirmed the presence of host-contributed lipid in some specimens. Although this is a low incidence of aneurysm formation, umbilical vein grafts should be selected primarily for patients with limited life expectancy or for whom alternative materials with comparable or superior patency rates are not available or acceptable. Periodic angiography, particularly after 3 or 4 years, is recommended as a routine part of follow-up examinations. Improved graft materials and control of host environmental factors are potential means to reduce the noted degradation.

Remote profunda femoral bypass for limb salvage.

Patients with patency of the distal segment of the profunda femoral arteries can be subjected to a direct end-to-side bypass with either tissue or synthetic grafts to increase blood flow to the lower extremity. The effectiveness and durability of this procedure will be enhanced by patency of the popliteal artery. Diffuse profunda femoris disease, popliteal or tibial peroneal obliterative disease and gangrenous lesions tend to militate against the success of this operation as an isolated procedure without augmenting flow to the distal part of an artery in the leg. Of 18 remote profunda femoris bypasses performed during a four year period, early amputation was required in two patients because of inadequate distal flow and the inability to establish downstream reconstruction. In one patient, an early bypass to the peroneal artery was required following closure of the profunda femoris bypass. The remaining 15 bypasses resulted in limb salvage and significant relief of symptoms. Three patients subsequently required secondary downstream reconstructions. The profunda femoris is surgically accessible for a long length and can serve as an adequate source of blood to the leg and foot in selected patients.

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.

The role of the peroneal artery for limb salvage.

Peroneal artery revascularization was performed in 61 cases for limb salvage and compared to a comparable group of 89 tibial artery reconstructions. Preoperative arteriography is essential to define runoff quality and pedal arch integrity. Intraoperative arteriography and flow determinations minimize failures due to technical error and provide some indication of the prognosis for graft patency. Failure to augment flow by at least 50% suggests pedal arch deficiency and is predictive for early graft closure. Cumulative patency for peroneal bypass was 55 +/- 8% at 1 year and 38 +/- 10% at 30 months compared to 63 +/- 6 and 59 +/- 7% for tibial reconstructions at the same time intervals. Most graft failures occurred within the first six months. Nineteen peroneals have been followed for more than one year with only three failures occurring. Improved criteria for case selection resulted in an 80% decrease in the number of failed grafts for the second half of this series. A similar reduction was noted for secondary operations. Results obtained with good quality saphenous veins (37 +/- 13% at 30 months) and glutaraldehyde tanned umbilical veins (53 +/- 11%) depend more on technical, pathologic and biologic factors than on the particular graft material employed. The mortality rate at 30 days was 3.3% and compared favorably with other limb salvage procedures and with primary amputations. Cumulative patient survival with functional limbs was 79 +/- 9% at 30 months and was distinctly superior to reported data on survival of amputees. A cumulative limb salvage rate of 79 +/- 6% at 30 months for the peroneal group makes such reconstructions definitely favorable to uniform limb ablation.

Evaluation of intraoperative arteriography as a routine for vascular reconstructions.

A retrospective analysis of 391 intraoperative arteriograms performed after reconstruction operations on the carotid, aorta and lower extremity vasculature showed the value of incorporating this procedure as a routine only for the last mentioned site. Identification and correction of inadequacies due to technique are possible. Revisions in technique based upon these experiences have significantly diminished their incidence. Routine intraoperative arteriography for revascularization procedures of the lower extremity has further enabled us to classify reliably the runoff and correlate these findings with subsequent graft patency. Late graft closure, predominantly due to progressive or accelerated obliterating atherosclerosis in the distal circulation, occurred almost exclusively within the first year following reconstruction in those patients identified as having poor runoff by intraoperative arteriography. This group, in particular, should be closely monitored by noninvasive physiologic means and even post-operative arteriography to enable either prophylactic or therapeutic correction. In some instances, based upon intraoperative arteriography or subsequent studies, fruitless and potentially harmful reoperative vascular procedures may be obviated.

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.

The use of modified human umbilical cord vein in femoral popliteal reconstruction.

Glutaraldehyde-tanned human umbilical cord veins were employed for reconstruction of the femoral popliteal segment in 80 instances. The primary indication for surgery was imminent loss of limb. The cumulative patency to 20 months was 84.8 percent. The primary mechanism for graft failure was thrombosis usually due to progressive atherosclerosis of the distal circulation (6 cases). There were no instances of infection, dilatation of the graft or aneurysm formation. The data indicate that the results obtained when the glutaraldehyde-tanned umbilical vein in femoral popliteal location are comparable and perhaps even superior to those obtained with the saphenous vein. This suggests that this graft material will be applicable as avascular prosthesis in many instances and will provide for limb salvage and function in patients who face potential loss of limb.

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.

Human umbilical cord. A new source for vascular prosthesis.

Reconstructions were performed to the popliteal, tibial, and peroneal arteries employing a modified umbilical cord vein prosthesis. The latter was obtained from human cords and was made available as an onshelf graft for surgery following glutaraldehyde tanning. The early patency and limb salvage rates are equivalent to those obtained with autogenous saphenous veins. Additional benefits include significant decreased operative time and morbidity. It is also probable that this new graft may be resistant to biodegradation and therefore may obviate many of the causes for late failure that occur with the use of living biologic tissues or collagen tubes. Long-term follow-up and study are essential to validate the results obtained thus far and to assess the potential of this new graft in a variety of vascular reconstructions.

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.

Successful arterial substitution with modified human umbilical vein.

Human umbilical veins were prepared as vascular grafts by tanning with dialdehyde starch or gluteraldehyde and by structural re-inforcement with an outer polyester fiber mesh. These grafts were implanted in baboons in the aortoiliac position for periods of 3 days to 9 months. There was no aneurysm formation and there was an excellent maintenance of patency as well as function. Histologic evaluation of the graft materials showed a dense collagen layer within the encircling polyester fiber mesh. A multicellular subintimal layer formed a discrete inner capsule. The inflammatory response with the umbilical component was insignificant. There was no evidence of rejection. This study suggests that the modified umbilical vein can serve as a satisfactory blood conduit. Experience with three short-term clinical implants supports the applicability and potential for this new vascular graft.

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.