Suitable Saphenous Vein Research Articles

The Development of Small-Caliber Vascular Grafts Using Human Umbilical Artery: An Evaluation of Methods.

Due to the prevalence of cardiovascular disease in the United States, small-caliber vascular grafts for coronary bypass surgery continue to be in high demand. Human umbilical arteries, an underutilized resource, were decellularized using zwitterionic (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate [CHAPS]) and ionic (sodium dodecyl sulfate [SDS]) detergents and evaluated as potential vascular grafts. Vessels were tested for decellularization efficacy, mechanical integrity, and recellularization potential. Hematoxylin and eosin staining and DNA quantification revealed moderate to successful removal of cells in both conditions. While CHAPS-decellularized vessels displayed collagen structure most similar to intact tissue, both CHAPS- and SDS-decellularized vessels demonstrated burst pressures lower than that of intact tissue. Alcian Blue staining and sulfated glycosaminoglycan (sGAG) quantification indicated the preservation of sGAG content after both decellularization pathways. Both conditions were also capable of recellularization with human umbilical vein endothelial cells, and the use of a basic fibroblast growth factor treatment did not have a significant effect on the density of adhered cells after 5 days. Whole CHAPS-decellularized vessels were successfully recellularized. Additionally, an evaluation of the effects of freeze-thaw cycles was performed. In summary, human umbilical arteries present a promising alternative for small-caliber vascular grafts due to their high availability and ability to be decellularized and recellularized for safe and successful implantation. Impact Statement Coronary heart disease accounts for one of nine deaths in the United States each year. Bypass surgery has been shown to decrease the risk of heart attack; however, many patients do not have a suitable saphenous vein, which is required to redirect blood flow around their blocked arteries. In this study, we evaluate decellularized umbilical artery as a potential small-diameter vascular graft based on its mechanical properties and its recellularization potential.

Comparison of Cryopreserved Arterial Allografts Versus Heparin-bonded Vascular Grafts in Infragenicular Bypass for Chronic Limb Threatening Ischemia

The purpose of this study was to compare cryopreserved arterial allograft (CAA) to heparin-bonded prosthesis (HBP) in infragenicular bypasses for patients with chronic limb-threatening ischemia (CLTI). This retrospective study took place in 2 university hospitals and included 41 consecutive patients treated for CLTI. In the absence of a suitable saphenous vein, an infragenicular bypass was performed using either CAA (24 cases) or HBP (17 cases). Kaplan-Meyer analysis compared primary and secondary patency and amputation-free survival rates. Binomial logistic regression analyzed risk factors for major amputation and thrombosis. The mean followup was 18.5months (±14.3) in the CAA group, 17.6 (±6.1) in the HBP group. In the CAA group, primary and secondary patency rates at 12months were 52% (±10.6) and 61% (±10.3), compared to 88% (±7.8) and 94% (±5.7) in the HBP group, respectively. The difference in patency rates was not statistically different (P=0.27 and P=0.28, respectively). The statistically significant factors of graft thrombosis were, a stage 4 from the WIfI classification (Wound Ischemia foot Infection) with a 6 times higher risk (P=0.04), and a distal anastomosis on a leg artery with a 9 times higher risk of thrombosis (P=0.03). Amputation-free survival rates at 18months were similar between the groups (CCA: 75% (±9) versus HBP: 94% (±6), P=0.11). Patients classified as WIfI stage 4 had 13 times higher odds to undergo major amputation than patients with WIfI stage 2 or 3 (95% CI, 1.16-160.93; P=0.04). The intervention was longer in the CCA group of 74min (278min±86) compared to the HBP group (203min±69). This difference was statistically significant (95% CI, 17.86-132.98), t(35)=2.671, P=0.01. CCA is not superior to HBP in infragenicular bypasses for CLTI, and may not be worth the extra cost and the longer operative duration.

Response to Letter to Editor

We would like to thank Dr Chaudhuri for his in-depth response on our recent publication “Dacron or ePTFE for femoro-popliteal above-knee bypass grafting: short and long-term results of a multicentre randomised trial.” Eur J Vasc Endovasc Surg 2009; 37: 457–463. Indeed it was mentioned that the patency rates with large-caliber prosthetic grafts in the fem-distal position (8 mm instead of 6 mm) were maybe better.1Abbott W.M. Green R.M. Matsumoto T. Wheeler J.R. Miller N. Veith F.J. et al.Prosthetic above-knee femoropopliteal bypass grafting: results of a multicenter randomized prospective trial. Above-Knee Femoropopliteal Study Group.J Vasc Surg. 1997 Jan; 25: 19-28Google Scholar, 2Green R.M. Abbott W.M. Matsumoto T. Wheeler J.R. Miller N. Veith F.J. et al.Prosthetic above-knee femoropopliteal bypass grafting: five-year results of a randomized trial.J Vasc Surg. 2000 Mar; 31: 417-425Google Scholar Unfortunately all these studies were flawed by nonrandomised design and potential selection bias. There is no level 1 evidence which clearly showed the better results of 8 mm prostheses in the femoro-distal position. We agree that new graft technologies might give better results compared to both, the standard Dacron and ePTFE, we used in our study. The older vascular surgeons remembered the “strong expert opinion” that patency rates with PTFE femoro-popliteal bypass above and below the knee were equal to or better than those with the same operation performed with saphenous vein.3Veith F.J. Moss C.M. Fell S.C. Rhodes B.A. Somberg E. Weiss P. et al.Expanded polytetrafluorethylene grafts in reconstructive arterial surgery. Preliminary report of the first 110 consecutive cases for limb salvage.JAMA. 1978 Oct 20; 240: 1867-1869Google Scholar This “evidence” was the background of our prospective RCT which clearly showed the opposite of the opinion of the experts in the 80th. Our group was also involved in the prospective non-consecutive cohort study of the Gore–Tex Propaten Vascular Graft in the femoro-distal position. The design of this study lodged all the potential risks of bias.4Gurusamy K.S. Gluud C. Nikolova D. Davidson B.R. Assessment of risk of bias in randomised clinical trials in surgery.Br J Surg. 2009; 96: 342-349Google Scholar The primary patency result of 91% of the Gore Propaten resembles our 1-year patency result of Dacron.5Walluscheck K.P. Bierkandt S. Brandt M. Cremer J. Infrainguinal ePTFE vascular graft with bioactive surface heparin bonding. First clinical results.J Cardiovasc Surg (Torino). 2005; 46: 425-430Google Scholar The two-year primary patency was also comparable with our Dacron result.6Peeters P. Verbist J. Deloose K. Bosiers M. Results with heparin bonded polytetrafluoroethylene grafts for femorodistal bypasses.J Cardiovasc Surg (Torino). 2006 Aug; 47: 407-413Google Scholar We agree with Dr Chaudhuri that we should not ignore possible renewals of allograft materials but he should also agree with us that we should learn from the past. Only proper designed RCTs without a mix of above-knee and below-knee bypass grafts could prove that heparin bounding ePTFE grafts should become the first choice allograft material in the femoro-distal position. Lacking this evidence so far we still conclude that Dacron is the preferential graft material in the above-knee fem-pop position if a suitable saphenous vein is absent. Re: Dacron or ePTFE for Femoro-popliteal Above-Knee Bypass Grafting: Short- and Long-term Results of a Multicentre Randomised Trial, van Det et al. in Eur J Vasc Endovasc Surg (2009) 37, 457–463European Journal of Vascular and Endovascular SurgeryVol. 38Issue 2PreviewI read with interest the paper by the above authors that challenges the more conventional use of ePTFE for prosthetic above-knee femoropopliteal bypasses. A few issues arise: firstly, the use of grafts of 6 mm diameter when an 8 mm graft is an option, which is not an unconventional one. The authors have also ignored the issue of heparin-bonded ePTFE grafts such as the Gore Propaten vascular graft in the discussion, which has demonstrated 84% and 91% 1-year primary patency rates,1,2 which is also supported on a haematological basis. Full-Text PDF Open Archive

Cerebral revascularization using cadaveric vein grafts

Background Use of cadaveric cryopreserved saphenous vein grafts (CSVGs) has been described for peripheral vascular and coronary revascularization. The aim of this study is to recognize CSVGs as a potential alternative to autologous conduits for extracranial-intracranial (EC-IC) bypass in patients without available or suitable saphenous vein graft or radial artery. We report the short-term patency rate of CSVGs in EC-IC bypass. Methods We present our preliminary experience in 10 patients using CSVG for cerebral revascularization. Data regarding operative indications, patient demographics, and bypass patency were collected. Results The average age was 56 years old with equal sex distribution. The indications for the procedure were giant aneurysms in 7 patients, medically refractory vertebrobasilar ischemia in 2, and a skull base tumor in 1. ABO/Rh blood group compatible CSVG was used in each case. Postoperative angiography demonstrated patency in all cases. Quantitative magnetic resonance angiography was performed in 8 patients, demonstrating a mean bypass flow of 109 mL/min ± 19 mL/min (mean ± SE). Conclusions Use of CSVG for EC-IC bypass has not previously been reported. In our series, the short-term patency rate was 100%, better than that found in cardiac and peripheral vascular series, possibly because of the higher flow in EC-IC bypasses. Our preliminary experience suggests that CSVGs may be an option in patients without available autologous conduits, although longer follow-up is needed to assess long-term patency.

Superficial Femoral Artery Autograft Reconstruction for Complicated Popliteal Artery Entrapment Syndrome

We present an alternative surgical approach to popliteal artery entrapment syndrome with vascular complications in the absence of a suitable saphenous vein. Three patients (29, 35, and 78 years old) with thrombotic and/or aneurysmal lesions of the popliteal artery from popliteal artery entrapment syndrome were treated with superficial femoral artery autograft reconstruction. The procedure was performed through a medial approach. The superficial femoral artery was harvested in the upper third of the thigh and used as the conduit for reconstruction and the harvested segment was replaced by a polytetrafluoroethylene graft. At follow-up, patients were asymptomatic and duplex ultrasound revealed patent reconstruction with no morphological abnormalities.

Long-term experience in autologous in vitro endothelialization of infrainguinal ePTFE grafts

Based on a previous randomized study showing significantly superior patency rates for in vitro endothelialized expanded polytetrafluoroethylene (ePTFE) grafts we investigated whether it was feasible for a nontertiary institution to offer autologous in vitro endothelialization to all elective infrainguinal bypass patients who had no suitable saphenous vein available. Over a period of 15 years, 310 out of 318 consecutive nonacute patients (age 64.7 +/- 8.6) received 341 endothelialized ePTFE grafts (308 femoropopliteal: 153 above knee [AK] and 155 below knee [BK] and 33 femorodistal). Autologous endothelial cells were harvested from short segments (3.9 +/- 1.1 cm) of subcutaneous veins (80% cephalic, 11% basilic, 2% external jugular, and 7% saphenous) and grown to mass cultures within 18.9 +/- 4.5 days before being confluently lined onto fibrin glue-coated ePTFE grafts. The graft diameter was 6 mm (64%) or 7 mm (36%). The overall procedure-related delay for graft implantation was 27.6 + 7.8 days. Growth failure prevented 2.5% of patients from receiving an endothelialized graft. The mean observation period was 9.6 years. Primary patencies were obtained from Kaplan-Meier survivorship functions. Explants for morphological analysis were obtained from eight patients. The overall primary patency rate of femoropopliteal grafts was 69% at 5 years (68% [AK] vs 71% [BK]) and 61% at 10 years (59% [AK] vs 64% [BK]). Primary patency of 7 mm vs 6 mm grafts was 78%/62% at 5 years and 71%/55% at 10 years. The difference between the two groups was statistically significant (log rank test P = .023; Breslow test P = .017). Stage I vs II/III patients showed 5-year patencies of 67% vs 73% (N.S.) and 10-year patencies of 61%% vs 53% (N.S.). The primary patency of femorodistal grafts was 52% at 5 years and 36% at 10 years. The limb salvage rate was 94% (fempop) vs 86% (femdistal) at 5 years and 89% vs 71% at 10 years. All retrieved samples showed the presence of an endothelium after 38.9 +/- 17.8 months. Autologous in vitro endothelialization was shown to be a feasible routine procedure at a nontertiary hospital. Explants confirmed the presence of an endothelium years after implantation while the primary patency in the particularly challenging subgroup of patients without a suitable saphenous vein resembles that of vein grafts.

Superficial femoral artery autograft reconstruction in the treatment of popliteal artery aneurysm: Long-term outcome

This prospective, observational study evaluated the safety and efficacy of superficial femoral artery autograft reconstruction in the treatment of popliteal artery aneurysms in the absence of a suitable saphenous vein. From March 1997 to April 2007, data from patients with popliteal artery aneurysms treated by superficial femoral artery reconstruction were prospectively collected in two centers. The procedure was performed through a medial approach. The superficial femoral artery was harvested in the upper third of the thigh and used as the conduit for reconstruction, and the harvested segment was replaced by a polytetrafluoroethylene graft. The patients were observed for survival, limb salvage, and reconstruction patency. The results were calculated by the Kaplan-Meier method. During the 10-year study period, 37 popliteal artery aneurysms in 32 patients (all men; median age, 71 years) were treated by reconstruction using the superficial femoral artery. Indications for surgical treatment were symptomatic or complicated aneurysms in 11 (30%). Four (11%) of the 37 popliteal artery aneurysms were thrombosed, and 33 (89%) were patent. At surgery, 35% had a single vessel runoff. Because of acute ischemia, reconstruction was performed as an emergency procedure in three patients (8%). There were no perioperative deaths, early amputations, or early thrombosis. The mean follow-up period was 36 months (range, 7-103 months). Two grafts thrombosed during follow-up. At 3 years, the primary and secondary patency rates were 86% and 96%, and overall limb salvage was 100%. Follow-up duplex ultrasonography did not detect any aneurysmal dilatation of the autograft. Our experience shows that superficial femoral arterial reconstruction is a safe and useful treatment option in patients with popliteal artery aneurysms who lack suitable saphenous veins. This reconstruction seems to be a good alternative to prosthetic bypass crossing the knee joint, and our results suggest that this study should be continued.

Early Results of Lower Extremity Infrageniculate Revascularization with a New Polytetrafluoroethylene Graft

When an autologous vein is not available for lower extremity revascularization, prosthetic grafts are often required. However, prosthetic bypass grafts have limited patency for infrageniculate reconstruction. To potentially improve patency, a new geometric modification of the polytetrafluoroethylene (PTFE) graft, Distaflo (Impra, Tempe, AZ), has been developed for lower extremity bypass. We reviewed our early experience with the Distaflo graft in patients who required infrageniculate bypass for lower extremity ischemia when no suitable autologous saphenous vein was available. All patients were maintained on warfarin anticoagulation postoperatively. All grafts were followed at 6- to 12-week intervals with duplex ultrasound evaluation. Patient characteristics, operative procedures, and graft surveillance information were maintained on a computerized registry. Thirty-two patients with limb-threatening ischemia underwent 35 infrageniculate reconstructions with a Distaflo graft between February 26, 1999, and August 24, 2000. Thirty-two of 35 bypasses were performed on extremities that had previously undergone a surgical procedure. Forty-eight previous revascularization procedures were done on these 25 extremities. Thirty grafts were constructed to the tibial outflow sites, whereas the remaining five grafts were placed to the below-knee popliteal artery. One patient died on the second postoperative day secondary to unrelated causes, and only one graft (3%) failed during the same hospitalization. Fifteen of 35 grafts (43%) remained patent 1 to 30 months later. Four patent grafts (6%) were ligated between 2 and 14 months for infectious indications. When considering the 20 failed grafts, 9 patients underwent major amputation, 5 patients remain with chronically ischemic limbs, and 6 patients underwent additional bypass grafts. Twenty-three patients (72%) maintained limb salvage. The Distaflo PTFE graft achieves promising early patency for complex infrageniculate revascularization and may be used as an alternative conduit in patients with critical limb ischemia who do not have an adequate vein for lower extremity revascularization.

Diabetic revascularization: improving limb salvage in the absence of autogenous vein.

Summary Diabetic patients can be offered opportunities for lower extremity revascularization with the expectation of results equal to those in the nondiabetic population. For those diabetics in danger of limb loss without adequate saphenous vein, alternatives exist for distal bypass resulting in acceptable long-term patency and limb salvage. As the population ages and approaches toward limb salvage become more aggressive, vascular surgeons will require alternative conduits to autogenous saphenous vein in a certain subset of patients. A PTFE graft with a distal vein patch may prove an acceptable alternative in the absence of saphenous vein. A multicenter prospective randomized trial may be of benefit to address the question of the best alternative for the patient without suitable autogenous saphenous vein for limb salvage. Until then, we will offer the patient without adequate vein PTFE bypasses to tibial arteries for limb salvage with the addition of a distal vein patch.

The biocompound method in coronary artery bypass operations: surgical technique and 3-year patency

Background. Complete arterial revascularization may be unsafe in patients with a high operative risk. In patients with varicose ectatic veins, the biocompound technique, which uses unsuitable autologous veins, enables the surgeon to influence the bypass graft wall stress levels and diameter. This report summarizes the 3-year patency of 53 patients, the survival rate of 200 patients, and operative technical considerations. Methods. Biocompound grafts were used for aortocoronary bypass in 200 patients who were considered inappropriate subjects for complete arterial revascularization and who had unsuitable saphenous veins. Results. The mortality rate (30 days) of 200 patients was 3.5%. The 3-year survival rate was 88.5%. The patency rate of the left internal thoracic artery (LITA) after 3 years was 97.3%, of the native vein was 68.7%, and of the biocompound graft was 68.3%. The LITA showed a superior patency rate ( p = < 0.05). Conclusions. The LITA is the first choice in coronary bypass operation. The biocompound technique is a reliable method to achieve complete revascularization in patients with a lack of suitable saphenous veins.

Clinical and Biological Relevance of Vein Cuff Anastomosis

Since a significant number of patients do not have suitable autologous saphenous vein for femorodistal bypass, the search for alternative graft material continues. The most commonly used prosthetic material is Polytetrafluoroethylene, however because of the poor patency of these grafts in the below knee position, a variety of techniques have been tried to improve their patency. A series of studies utilizing venous cuffs at the distal anastomosis have showed improved patency of PTFE grafts. We have reviewed the biological basis for graft failure and the literature for possible mechanical explanations.

Clinical autologous in vitro endothelialization of infrainguinal ePTFE grafts in 100 patients: A 9-year experience

Clinical in vitro endothelialization was assessed for its ability to improve the long-term patency of prosthetic femoropopliteal bypass grafts. Between June 1989 and May 1998, 100 patients received 113 in vitro endothelialized expanded polytetrafluoroethylene grafts (ePTFE). Bilateral implantations were performed in 13 patients. In phase 1 of the study, 24 patients received 27 endothelialized grafts and 16 patients received 17 untreated grafts. In phase 2, endothelialization was offered to all patients who did not have a suitable saphenous vein available. Phase 2 began in June 1993 and included 76 patients who received 86 endotheliazed ePTFE grafts. In all, 100 patients had autologous endothelial cells harvested from 4- to 5-cm segments of a subcutaneous vein. In phase 1, the external jugular vein was used. In phase 2, the cephalic vein was used. These cells were grown to first-passage mass cultures and were lined confluently onto 6-mm ePTFE grafts, pre-coated with fibrin glue. Patency assessment for Kaplan-Meier survivorship analysis was determined by using duplex sonography and angiography. In phase 1, the Kaplan-Meier method revealed a primary 9-year patency rate for 65% for the endothelialized group, versus 16% for the control group (log-rank test, P = .002; Wilcoxon test, P = .003). In phase 2, the 5-year primary patency rate for all in vitro endothelialized infrainguinal reconstructions was 68% (66% for above-the-knee grafts and 76% for below-the-knee grafts). Nine years of clinical in vitro endothelialization provided strong evidence that autologous endothelial cell lining improves the patency of small-diameter vascular grafts and that a cell culture-dependent procedure can be used in a clinical routine.

Clinical autologous in vitro endothelialization of infrainguinal ePTFE grafts in 100 patients: A 9-year experience

Background: Clinical in vitro endothelialization was assessed for its ability to improve the long-term patency of prosthetic femoropopliteal bypass grafts. Methods: Between June 1989 and May 1998, 100 patients received 113 in vitro endothelialized expanded polytetrafluoroethylene grafts (ePTFE). Bilateral implantations were performed in 13 patients. In phase 1 of the study, 24 patients received 27 endothelialized grafts and 16 patients received 17 untreated grafts. In phase 2, endothelialization was offered to all patients who did not have a suitable saphenous vein available. Phase 2 began in June 1993 and included 76 patients who received 86 endotheliazed ePTFE grafts. In all, 100 patients had autologous endothelial cells harvested from 4- to 5-cm segments of a subcutaneous vein. In phase 1, the external jugular vein was used. In phase 2, the cephalic vein was used. These cells were grown to first-passage mass cultures and were lined confluently onto 6-mm ePTFE grafts, pre-coated with fibrin glue. Patency assessment for Kaplan-Meier survivorship analysis was determined by using duplex sonography and angiography. Results: In phase 1, the Kaplan-Meier method revealed a primary 9-year patency rate for 65% for the endothelialized group, versus 16% for the control group (log-rank test, P = .002; Wilcoxon test, P = .003). In phase 2, the 5-year primary patency rate for all in vitro endothelialized infrainguinal reconstructions was 68% (66% for above-the-knee grafts and 76% for below-the-knee grafts). Conclusions: .Nine years of clinical in vitro endothelialization provided strong evidence that autologous endothelial cell lining improves the patency of small-diameter vascular grafts and that a cell culture–dependent procedure can be used in a clinical routine.(Surgery 1999;126:847-55.)

Early experience with cryopreserved arterial allografts in below-knee revascularization for limb salvage

Background: Below-knee revascularization for limb salvage in the absence of a suitable autogenous saphenous vein is a frequent challenge associated with a high amputation rate. The aim of this prospective study was to evaluate the usefulness of cryopreserved arterial allografts in such cases. Methods: Arterial allografts were harvested from multiple organ donors and cryopreserved at −80°C. From March 1993 to December 1997, 35 cryopreserved arterial allografts were used as below-knee bypasses for repeated limb salvage in 32 patients. There were 15 men and 17 women with a mean age of 75 years (±10.7). Seven patients had rest pain and 25 patients (78%) had gangrene or nonhealing ulceration. Runoff was through a single tibial vessel in 25 cases (71%) and two vessels in 10 cases. Previous ipsilateral bypasses had been done in 26 of 35 limbs (74%). Patients were followed up prospectively for an average period of 18 months (range 2 to 56). Results: Aneurysmal dilatation occurred in two patent grafts, requiring segmental replacement at 13 and 18 months, respectively. The overall primary patency rate was 75% at 6 months, 57% at 12 months, and 39% at 18 months. The overall secondary patency rate was 75% at 6 months, 75% at 12 months, and 59% at 18 months. Overall limb salvage rate was 80% at 12 months, 73% at 18 months. Conclusions: These early data indicate that below-knee bypass with arterial allografts results in acceptable patency and limb salvage. Arterial allografts may be a useful alternative to other arterial substitutes in a difficult group of patients with critical ischemia and no suitable saphenous vein.

Quality of the Long Saphenous Vein Conduits Used for Coronary Artery Bypass Grafting Operations

The aim of this study was first to select preoperatively suitable long saphenous vein (LSV) segments by using color flow duplex imaging (CFDI) and second to evaluate the quality of the harvested LSVs histologically. Forty LSVs in 38 consecutive patients (mean age 63 years) were examined by CFDI for patency and luminal diameter. None of the patients had documented previous deep venous thrombosis or superficial thrombophlebitis. Perioperatively, 79 LSV specimens were harvested from the ankle, knee, and midthigh regions and examined histologically for wall calcification and fibrosis. According to the amount of fibrosis present the specimens were classified as being normal or mildly, moderately, or severely affected. All LSVs were found patent and nonvaricose, and their diameter ranged from 0.18 to 0.54 cm at the ankle, 0.29 to 0.69 cm at the knee, and 0.25 to 0.77 cm at the midthigh level. On histology 11% of the specimens were found to be normal, and 43% were mildly, 38% moderately, and 8% severely fibrotic. Also, various grades of fibrosis were found in different sites of the same vein. None of the specimens had calcification. It is concluded that the majority of the LSVs used for coronary artery bypass grafting have some degree of fibrosis. The histologic appearance of the LSV wall in a particular site cannot predict the condition of vein throughout its length. CFDI can be useful in the perioperative conduit selection.

Eight Years of Clinical Endothelial Cell Transplantation

After years of in vitro studies and non human primate implantations, the authors commenced their clinical program of autologous in vitro endothelialization of polytetrafluoroethylene (ePTFE) grafts in 1989. Based on the successful 3 year results of a pilot study (Phase I) with 49 patients (1:2 randomization, assigning 33 patients to the endothelialized group and 16 to the control group), the authors offered in vitro endothelialized grafts to all patients who did not have a suitable saphenous vein available from June 1993 onward (Phase II). Another 72 patients received 81 successfully endothelialized ePTFE grafts in this second phase of the transplantation program. In the Phase I randomized trial, the Kaplan-Meier survivorship analysis showed a primary 3 year patency rate of 84.7% for endothelialized grafts and 55.4% for control grafts. After 5 years, it was 73.8% for the endothelialized group and 20.8% for the controls. At the end of the 7 year follow-up period, the primary patency rate for endothelialized grafts remained high at 73.8%, whereas that for the control grafts dropped to zero (log-rank test; p = 0.001 and Wilcoxon test; p = 0.003). The subsequent Phase II routine clinical implantation of endothelialized ePTFE grafts showed a 3 1/2 year primary patency rate of 72.9% for all femoropopliteal reconstructions. The authors' overall 7 year follow-up with endothelialized femoropopliteal ePTFE grafts (n = 108) shows a patency of 66.0%. When pretreated with fibronectin (n = 43), the 7 year patency was 72.1%. In the above-knee group, the 7 year patency for fibronectin treated grafts was as high as 75.8% (n = 36). After 8 years of clinical endothelial cell transplantation, the authors conclude that in vitro endothelialization of ePTFE grafts results in a patency rate of arterial prostheses comparable with that of vein grafts.

Cryopreserved Arterial Allografts for Limb Salvage in the Absence of Suitable Saphenous Vein: Two-Year Results in 20 Cases

From January 1992 to November 1992, 20 cryopreserved arterial allografts were used as below-knee bypasses for repeated limb salvage in 18 patients lacking saphenous vein grafts. Arteries were obtained during multiorgan harvesting. A scheduled program of cryopreservation with 15% dimethylsulfoxide was used. Mean storage period was 37 days. All cases were matched for blood group compatibility. Patency was checked at 10 and 90 days and twice a year thereafter. Conventional arteriography was routinely performed 3 months postoperatively. Average follow-up was 26.8 months for the 18 patients and 20.8 months for the 20 bypass grafts. No patients were lost to follow-up. Aneurysmal dilation developed in one graft, which was replaced by another homograft. During follow-up 10 grafts occluded: five once, four twice, and one four times. These 10 grafts underwent a total of 16 reinterventions. Thrombectomy with angioplasty was performed 15 times and graft replacement once because of proximal and distal arterial deterioration. Primary actuarial patency was 68% at 1 year and 42% at 2 years. Secondary actuarial patency was 89% at 1 year and 72% at 2 years. Preliminary results of cryopreserved arterial allografts for repeated limb salvage in the absence of available saphenous veins are encouraging. Further studies are needed to determine the long-term deterioration rate of cryopreserved arterial allografts.

A Technique to Harvest the Inferior Epigastric Arteries for Coronary Bypass Procedures

The demonstrated superior long-term patency of the internal mammary artery (IMA) over the saphenous vein (SV) has prompted the use of other arterial grafts, particularly for younger patients and patients without a suitable SV. We have used the single or bilateral inferior epigastric arteries (IEA) as a detached arterial conduit in 27 patients undergoing coronary artery bypass operations (CABG). In this report we describe the surgical anatomy of the IEA, preoperative noninvasive evaluation by duplex scan, our harvesting technique, and early surgical experience.

Vascular Craft Selection

Twenty to thirty per cent of patients with arterial injuries and some patients with venous injuries require interpositional grafting. The first choice of grafting material for both arterial and venous injuries is autogenous vein. Injuries to large vessels such as the aorta and superior vena cava may necessitate synthetic prostheses. Synthetic aortic prostheses have excellent long-term patency rates, but the same materials are much less likely to remain patent in the vena cava. Panel or spiral grafts constructed from saphenous vein appear to be the best replacement for this vessel. Autogenous veins are present in different diameters ranging from a mean of 6.4 mm in the saphenous vein to a mean of 1.8 cm in the internal jugular vein. The thickest autogenous vein is the saphenous vein, and thus it is preferred for medium-sized and small arteries. The authors prefer the larger 7.5-mm cephalic vein for replacement of medium-sized veins. In the absence of suitable saphenous vein, the cephalic vein is also the choice for arterial interposition grafts. Although there are few reports of the use of arterial autografts in vascular trauma, the surgeon should be aware that autografts may be ideal for vascular injuries in children and for isolated injuries with severe contamination. Finally, the use of synthetic grafts in injuries where adequate tissue coverage is not possible may result in immediate limb salvage, but the incidence of limb loss in this situation will be extremely high.

The superficial femoral artery as a conduit: An alternative to prosthetic material

The occluded superficial femoral artery is almost universally present in atherosclerosis obliterans and requires vascular reconstruction. As an alternative autogenous conduit, when a suitable saphenous vein is not available, the properly prepared superficial femoral artery can obviate the need for prosthetic material. The technique for preparing the artery for use as a graft is discussed. A case of the superficial femoral artery used as an autogenous conduit is presented.