Meta-analysis of allograft bypass grafting to infrapopliteal arteries

Evaluation of Arterial and Venous Allografts in Subinguinal Bypasses

BACKGROUND

Autologous saphenous vein is the preferred conduit for below-the-knee bypasses in patients with critical limb-threatening ischemia. Alternative graft must be considered for patients without (autologous saphenous vein). The aim of this article is to evaluate the mid-term performance of arterial allograft (AA) and venous allograft (VA) used as alternative conduits.

METHODS

This retrospective study included patients with critical limb-threatening ischemia, with or without a history of homolateral femoropopliteal bypass, and no autologous veins were available who underwent infrainguinal arterial reconstructions using VA or AA from 2008 to 2018. Patients undergoing revision operations for infected bypasses were excluded. Primary patency (PP), primary assisted patency, secondary patency, major amputation, and death from any cause were the endpoints. For each event, a set of analyses were performed.

RESULTS

Overall, 111 patients (63 VAs and 48 AAs) were included, with 108 having below-the-knee bypass. The median follow-up time was 27.8 months (15.6-37.4). The difference in PP between the 2 allograft types was significant (P = 0.049), with 65.9% (43.7-81.0), 44.1% (24.2-62.3), and 44.1% (24.2-62.3) in the AA group, respectively, at 6, 12, and 18 months, whereas 55.6% (40.0-68.6), 46.0% (30.6-60.2), and 33.2% (18.2-49.0) in the VA group. The choice of an AA over a VA was an independent factor associated with patency (for PP: hazard ratio [HR] = 0.43 [0.24-0.75], P = 0.003); primary assisted patency: HR = 0.52 (0.30-0.89], P = 0.018; and secondary patency: HR = 0.49 (0.27-0.88), P = 0.016. The allograft type did not affect either the incidence of major amputation or death from any cause (respectively, HR = 1.20 [0.49-2.93], and 0.88 [0.37-2.14]).

CONCLUSIONS

The nature of the allograft appears to influence the patency of infrainguinal reconstruction, but not the course of the disease. Performant alternative grafts answering infectious issues are needed.

Physico-mechanical and biological evaluation of heparin/VEGF-loaded electrospun polycaprolactone/decellularized rat aorta extracellular matrix for small-diameter vascular grafts

Although the continuous development of small-diameter vascular grafts (SDVGs) (D < 5 mm) continues, most vascular grafts are made from synthetic polymers, which lead to serious complications from arteriosclerosis, thrombosis, and vascular ischemia. Here, to address these shortcomings, we combine synthetic polymers with natural decellularized small-diameter vessels and loaded with growth factor. We fabricated vascular grafts by electrospinning polycaprolactone (PCL) to decellularized rat aorta matrix (ECM) followed by heparin and vascular endothelial growth factor (VEGF) loading. In- vitro studies showed that PCL/ECM/VEGF vascular grafts, showed excellent hemocompatibility and biocompatibility properties. The vascular grafts implanted into the rat aorta revealed that the PCL/ECM/VEGF grafts promotes endothelial cells and smooth-muscle cells infiltration with a rate of FLK-1, ICAM1, and a-SMA distribution higher than that of the PCL and PCL/ECM vascular grafts at 2 weeks and 4 weeks after implantation. The PCL/ECM/VEGF vascular graft should be considered for potential small-diameter vascular grafts in clinical fields.

Supera stent implantation for the treatment of isolated popliteal artery disease systematic review and evaluation of current endovascular strategies

&lt;b&gt;Introduction:&lt;/b&gt; The anatomical location of the popliteal artery is one of the greatest challenges for percutaneous interventions. The biomechanical attributes of the vessel lead to higher rates of restenosis, stent fracture, and occlusion. Some surgeons consider the popliteal artery as a no stenting zone. Many specialists favor percutaneous transluminal angioplasty to be the first line of endovascular treatment in the popliteal artery with bail-out stent implantation if the results are suboptimal. The Supera peripheral stent system is a novel stent that has been manufactured with a high degree of flexibility and supposedly might be appropriate for implantation in the popliteal artery. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Aim:&lt;/b&gt; Evaluation of the performance of Supera stent in isolated popliteal artery disease in comparison to other methods of treatment. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Methods:&lt;/b&gt; As many as 92 articles were found in the databases and after full-text review, 4 studies matched the inclusion criteria and were evaluated. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Results:&lt;/b&gt; Primary patency rates of Supera implantation in an isolated popliteal artery at 12 months ranged from 68% to 90%. In all four studies, no stent fractures were observed. Only one study provided longer follow-up than 12 months and evaluated the performance of the Supera stent 36 months after implantation. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Conclusion:&lt;/b&gt; In conclusion, mentioned studies show promising and superior to other stent patency rates of the Supera stent regarding popliteal artery lesions. What is more, no stent fracture is promising regarding longer follow-up. However, more studies with longer follow-ups and direct comparison to other methods are required to fully evaluate Supera&apos;s performance in the popliteal artery.

Fresh cold-stored vascular allografts in subgenicular location: Our experience with rescue endovascular techniques

OBJECTIVE

Critical limb ischemia (CLI) is considered the most severe pattern of peripheral artery disease. CLI is associated with high rates of morbidity and mortality and a high risk of limb amputation. In the absence of appropriate autologous grafts, unsuitability of prosthetic bypasses and endovascular methods, fresh cold-stored venous allografts is an option. Endovascular interventional methods are essential methods for maintaining primary and secondary patency.

METHODS

A single-centre retrospective analysis of 82 surgical revascularizations using allogeneic vascular grafts and rescue endovascular techniques restoring and maintaining the patency of these allogeneic revascularizations in the period between 7/2005 and 7/2021.

RESULT

We have performed 82 allogeneic revascularizations in 75 patients (52 reconstructions in men /63.4%/, 30 reconstructions in women /36.6%/). The median age of patients was 68 years (49 min, 87 max). We subsequently had to intervene a total of 26 bypasses. We intervened in 30 acute occluded allogeneic bypass grafts and 9 failing stenotic bypass grafts. We performed 52 angiographies. The success rate of rescue endovascular procedures in primary allogeneic reconstruction with distal anastomosis to the popliteal artery is statistically significant (p <0.02) compared to procedures with distal anastomosis to the tibial and pedal bed. The cumulative patency (primary at time) of allogeneic reconstructions in our group was 89% after 1 month, 51.9% after 12 months, 24.2% after 3 years, 9.8% after 5 years. Limb salvage was 72.6% in 1 year, 53% in 3 years, 36.5% in 5 years, respectively.

CONCLUSION

Cold-stored venous allografts may be used for performing below-the-knee revascularization for CLI with acceptable results despite poor long-term patency. Rescue endovascular techniques are an essential method for restoring or maintaining the patency of these reconstructions. These techniques have a high success rate and no other alternative.

Characterization of a heparinized decellularized scaffold and its effects on mechanical and structural properties

Decellularization is a promising approach in tissue engineering to generate small-diameter blood vessels. However, some challenges still exist. We performed two decellularization phases to develop an optimal decellularized scaffold and analyze the relationship between the extracellular matrix (ECM) composition and mechanical properties. In decellularization phase I, we tested sodium dodecylsulfate (SDS), Triton X-100 (TX100) and trypsin at different concentrations and exposure times. In decellularization phase II, we systematically compared five combined decellularization protocols based on the results of phase I to identify the optimal method. These protocols tested cell removal, ECM preservation, mechanical properties, and residual cytotoxicity. We further immobilized heparin to optimal decellularized scaffolds and determined its anticoagulant activity and mechanical properties. The combined decellularization protocol comprising treatment with 0.5% SDS followed by 1% TX100 could completely remove the cellular contents and preserve the mechanical properties and ECM architecture better. In addition, the heparinized decellularized scaffolds not only had sustained anticoagulant activity, but also similar mechanical properties to native vessels. In conclusion, heparinized decellularized scaffolds represent a promising direction for small-diameter vascular grafts, although further in vivo studies are needed.

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

BACKGROUND

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).

METHODS

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.

RESULTS

The mean followup was 18.5 months (±14.3) in the CAA group, 17.6 (±6.1) in the HBP group. In the CAA group, primary and secondary patency rates at 12 months 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 18 months 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 74 min (278 min ± 86) compared to the HBP group (203 min ± 69). This difference was statistically significant (95% CI, 17.86-132.98), t(35) = 2.671, P = 0.01.

CONCLUSIONS

CCA is not superior to HBP in infragenicular bypasses for CLTI, and may not be worth the extra cost and the longer operative duration.

A systematic review of isolated radial artery harvesting as a conduit for lower limb bypass grafting

BACKGROUND

Whilst autologous vein conduits have been heralded as the first-line approach for patients undergoing lower limb bypass grafting procedures, patients with peripheral arterial occlusive disease may have exhausted venous options given prior use for cardiac surgery, varicose vein surgery, or lower limb revascularization. Hence, the use of a radial artery graft may serve as a viable alternative.

METHODS

The systematic review was performed in accordance to the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. An electronic search was performed on the following databases: Medline (via PubMed); EMBASE; Cochrane library to search for relevant publications. A narrative analysis was conducted.

RESULTS

Four publications were included in this review including two retrospective cohort studies, one case series, and one case report, with a total of 43 patients. The most common indication for lower limb bypass grafting was critical limb ischemia, and the radial artery was chosen as graft conduit, most commonly due to the absence of suitable arm or leg vein. There was one case of 30-day mortality and 11 reinterventions.

CONCLUSION

Despite the encouraging results, the paucity of high-quality studies prevents the establishment of any firm conclusion. This warrants the need for appropriately conducted randomized controlled trials to compare the radial artery graft to autologous vein grafts and prosthetic grafts for lower limb bypass grafting.

Retrograde Pedal Access-Cutting Edge or Comical?

Retrograde pedal access is a technique utilized with increasing frequency by many interventionists to address patients with advanced multilevel peripheral artery disease and significant comorbidities. This approach to revascularization is being used both in patients who fail traditional antegrade access and in some patients thought to be poor candidates for antegrade approach. However, the lack of randomized controlled trial data, or long-term results, coupled with the associated potential risks including dissection, spasm, and thrombosis have rendered retrograde pedal access a controversial topic. This article details the pros and cons associated with the debate surrounding retrograde pedal access and highlights the current literature and remaining questions regarding outcomes of this technique.

Comparison of angioplasty and bypass surgery for critical limb ischaemia in patients with infrapopliteal peripheral artery disease

BACKGROUND

Both infrapopliteal (IP) bypass surgery and percutaneous transluminal angioplasty have been shown to be effective in patients with critical limb ischaemia (CLI). The most appropriate method of revascularization has yet to be established, as no randomized trials have been reported. The aim of this study was to compare the outcomes of patients with similar characteristics treated using either revascularization method.

METHODS

Consecutive patients undergoing IP bypass and IP angioplasty for CLI (Rutherford 4-6) at a single institution were compared following propensity score matching. The study endpoints were primary, assisted primary and secondary patency, and amputation-free survival at 12 months, calculated by Kaplan-Meier analysis.

RESULTS

Some 279 limbs in 243 patients were included in the study. The two groups differed significantly with respect to the incidence of diabetes (P = 0·024), estimated glomerular filtration rate (P = 0·006), total lesion length (P < 0·001) and Rutherford classification (P = 0·008). These factors were used to construct the propensity score model, which yielded a matched cohort of 125 legs in each group. Primary patency (54·4 versus 51·4 per cent; P = 0·014), assisted primary patency (77·5 versus 62·7 per cent; P = 0·003), secondary patency (84·4 versus 65·8 per cent; P < 0·001) and amputation-free survival (78·7 versus 74·1 per cent; P = 0·043) were significantly better after bypass than angioplasty. However, limb salvage was similar (90·4 versus 94·2 per cent; P = 0·161), and overall complications (36·0 versus 21·6 per cent; P = 0·041) as well as length of hospital stay (18(4-134) versus 5(0-110); P = 0·001) were worse in the surgical bypass group.

CONCLUSION

There was no difference in limb salvage rates, but patency and amputation-free survival rates were better 1 year after bypass surgery.

Cold-stored cadaveric venous allograft for superior mesenteric/portal vein reconstruction during pancreatic surgery

BACKGROUND

SMV/PV resection has become common practice in pancreatic surgery. The aim of this study was to evaluate the technical feasibility and surgical outcome of using cold-stored cadaveric venous allografts (AG) for superior mesenteric vein (SMV) and portal vein (PV) reconstruction during pancreatectomy.

METHODS

Patients who underwent pancreatic resection with concomitant vascular resection and reconstruction with AG between January 2006 and December 2014 were identified from our institutional prospective database. Medical records and pre- and postoperative CT-images were reviewed.

RESULTS

Forty-five patients underwent SMV/PV reconstruction with AG interposition (n = 37) or AG patch (n = 8). The median operative time and blood loss were 488 min (IQR: 450-551) and 900 ml (IQR: 600-2000), respectively. Major morbidity (Clavien ≥ III) occurred in 16 patients. Four patients were reoperated (thrombosis n = 2, graft kinking/low flow n = 2) and in-hospital mortality occurred in two patients. On last available CT scan, 3 patients had thrombosis, all of whom also had local recurrence. Estimated cumulative patency rate (reduction in SMV/PV luminal diameter <70% and no thrombosis) at 12 months was 52%.

CONCLUSION

Cold-stored cadaveric venous AG for SMV/PV reconstruction during pancreatic surgery is safe and associated with acceptable long-term patency.

An Update on Methods for Revascularization and Expansion of the TASC Lesion Classification to Include Below-the-Knee Arteries: A Supplement to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II): The TASC Steering Comittee(.)

The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) guidelines were last updated in 2007 (TASC II) and represented the collaboration of international vascular specialties involved in the management of patients with peripheral arterial disease (PAD). Since the publication of TASC II, there have been innovations in endovascular revascularization strategies for patients with PAD. The intent of this publication is to provide a complete anatomic lower limb TASC lesion classification, including the infrapopliteal segment, and an updated literature review of new endovascular techniques and practice patterns employed by vascular specialists today.

An Update on Methods for Revascularization and Expansion of the TASC Lesion Classification to Include Below-the-Knee Arteries: A Supplement to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II)

The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) guidelines were last updated in 2007 (TASC II) and represented the collaboration of international vascular specialties involved in the management of patients with peripheral arterial disease (PAD). Since the publication of TASC II, there have been innovations in endovascular revascularization strategies for patients with PAD. The intent of this publication is to provide a complete anatomic lower limb TASC lesion classification, including the infrapopliteal segment, and an updated literature review of new endovascular techniques and practice patterns employed by vascular specialists today.

An Update on Methods for Revascularization and Expansion of the TASC Lesion Classification to Include Below-the-Knee Arteries

The Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC) guidelines were last updated in 2007 (TASC II) and represented the collaboration of international vascular specialties involved in the management of patients with peripheral arterial disease (PAD). Since the publication of TASC II, there have been innovations in endovascular revascularization strategies for patients with PAD. The intent of this publication is to provide a complete anatomic lower limb TASC lesion classification, including the infrapopliteal segment, and an updated literature review of new endovascular techniques and practice patterns employed by vascular specialists today.

Cryopreserved autologous saphenous vein for staged treatment of bilateral popliteal aneurysms: report of three cases

Popliteal artery aneurysms are the most common aneurysmal disease of the lower extremity. Although endovascular solutions are gaining consensus, open surgery with interposition grafting remains the standard of care. The great saphenous vein (GSV) is the most commonly used conduit and shows the best long-term results. However, optimal vein segments can sometimes be unavailable, thus leading to the use of unsuitable segments or prosthetic grafts. We report the cases of 3 patients who had bilateral popliteal aneurysms and only 1 GSV that was considered suitable for grafting, without alternative venous segments. All patients underwent staged treatment with the use of the GSV. After the first operation, the remaining GSV was cryopreserved and then reused for the contralateral limb. All patients had an uneventful outcome. No graft occlusions and no aneurysmal dilatations were detected at follow-up. Cryopreservation of autologous vein for staged treatment of bilateral popliteal aneurysms is feasible and seems to avoid the risk of residual GSV loss during the time inbetween the interventions.

A cost-effectiveness analysis of infrainguinal bypass in the absence of great saphenous vein conduit

BACKGROUND

Good-quality great saphenous vein (GSV) is the preferred conduit for infrainguinal surgical revascularizations, but it is not available in all patients. We sought to identify the alternative conduit that would maximize cost-effectiveness in the context of infrapopliteal bypass for critical limb ischemia and nonhealing foot wounds.

METHODS

A Markov model was used to create a detailed simulation of 10-year outcomes in a hypothetical Edifoligide for the Prevention of Infrainguinal Vein Graft Failure (PREVENT) III-type patient cohort undergoing infrainguinal bypass for nonhealing foot wounds. The following management options were evaluated: (1) conservative therapy (local wound care, amputation as needed); (2) primary amputation; (3) bypass with autologous alternative vein (AAV), including arm or lesser saphenous vein; (4) bypass with GSV <3 mm in diameter; (5) bypass with polytetrafluoroethylene (PTFE); (6) cryopreserved venous allograft; and (7) cryopreserved arterial allograft. Estimates of 10-year total costs were incorporated into the model. Cost-effectiveness was measured in terms of incremental United States dollars per additional year of ambulation.

RESULTS

Bypass with AAV had the highest effectiveness as measured in median years of ambulation. After primary amputation, bypass with PTFE had the lowest total costs. With incremental cost-effectiveness ratios of $5325 and $21,228, bypass with PTFE or AAV appeared to be cost-effective alternatives to conservative therapy for nonhealing ischemic wounds. Primary amputation, GSV <3 mm, and allograft options were dominated (ie, more costly and less effective). Primary amputation was weakly dominated.

CONCLUSIONS

Bypass with PTFE or AAV appears to be a cost-effective option for the management of critical limb ischemia and nonhealing foot wounds when good-quality GSV is not available.

The peritoneum as a natural scaffold for vascular regeneration

Objective

The peritoneum has the same developmental origin as blood vessels, is highly reactive and poorly thrombogenic. We hypothesize that parietal peritoneum can sustain development and regeneration of new vessels.

Methods and Results

The study comprised two experimental approaches. First, to test surgical feasibility and efficacy of the peritoneal vascular autograft, we set up an autologous transplantation procedure in pigs, where a tubularized parietal peritoneal graft was covered with a metal mesh and anastomosed end-to-end in the infrarenal aorta. Second, to dissect the contribution of graft vs host cells to the newly developed vessel wall, we performed human-to-rat peritoneal patch grafting in the abdominal aorta and examined the origin of endothelial and smooth muscle cells. In pig experiments, the graft remodeled to an apparently normal blood vessel, without thrombosis. Histology confirmed arterialization of the graft with complete endothelial coverage and neointimal hyperplasia in the absence of erosion, inflammation or thrombosis. In rats, immunostaining for human mitochondri revealed that endothelial cells and smooth muscle cells rarely were of human origin. Remodeling of the graft was mainly attributable to local cells with no clear evidence of c-kit+ endothelial progenitor cells or c-kit+ resident perivascular progenitor cells.

Conclusions

The parietal peritoneum can be feasibly used as a scaffold to sustain the regeneration of blood vessels, which appears to occur through the contribution of host-derived resident mature cells.

Readily available tissue-engineered vascular grafts

Autologous or synthetic vascular grafts are used routinely for providing access in hemodialysis or for arterial bypass in patients with cardiovascular disease. However, some patients either lack suitable autologous tissue or cannot receive synthetic grafts. Such patients could benefit from a vascular graft produced by tissue engineering. Here, we engineer vascular grafts using human allogeneic or canine smooth muscle cells grown on a tubular polyglycolic acid scaffold. Cellular material was removed with detergents to render the grafts nonimmunogenic. Mechanical properties of the human vascular grafts were similar to native human blood vessels, and the grafts could withstand long-term storage at 4 °C. Human engineered grafts were tested in a baboon model of arteriovenous access for hemodialysis. Canine grafts were tested in a dog model of peripheral and coronary artery bypass. Grafts demonstrated excellent patency and resisted dilatation, calcification, and intimal hyperplasia. Such tissue-engineered vascular grafts may provide a readily available option for patients without suitable autologous tissue or for those who are not candidates for synthetic grafts.

Fifteen years of infrapopliteal arterial reconstructions with cryopreserved venous allografts for limb salvage

OBJECTIVE

The availability of autologous vein grafts remains the limiting factor in infragenual bypass surgery in many patients with critical limb ischemia (CLI). Alternatives such as prosthetic conduits are known to have a poor outcome and most are not resistant to infection. Based on previous experimental work, we started to use cryopreserved saphenous vein allografts for this indication 15 years ago. To evaluate their outcome, we performed a retrospective study of those bypasses with distal anastomosis on a crural or pedal vessel.

METHODS

Between November 1991 and December 2005, 108 cryopreserved great saphenous vein allografts were implanted for in 92 patients (42 women, 50 men) with a mean age of 71 years (range, 39-88 years). All patients received low-dose immunosuppressive therapy for up to 1 year after intervention. Follow-up was conducted until amputation, death, or the end of the study in March 2007.

RESULTS

Nondiabetic atherosclerosis the cause of CLI in 57%, 41% had diabetes, and 2% had Buerger disease. Forty-one conduits were performed for primary reconstructions and 67 for redo reconstructions. During a mean follow-up of 26.4 months, 69 occlusions occurred. Primary and secondary patency rates were 56% and 73% at 1 year, 32% and 60% at 3 years, and 17% and 38.5% at 5 years. Survival rates were 87.4% at 1 year and 64.5% at 5 years. At multivariate analysis, the intake of statins was predictive for improved patency (hazard ratio [HR], 0.09; P = .024) and for prolonged survival (HR, 0.335; P = .045). The presence of diabetes showed a trend for inferior patency (HR, 2.325; P = .116) and for decreased amputation risk (HR, 0.592; P = .078).

CONCLUSION

Cryopreserved saphenous vein allografts are a valuable alternative to prosthetic materials when autologous veins are not available. Our limb salvage and patency rates are higher then those described for prosthetic grafts at the infrapopliteal level in most studies. Moreover, these grafts are resistant to infection when performed for revascularization in patients with an infected ulcer. Better graft and patient selection, better graft surveillance and immunologic matching, and standard use of statins could possibly improve the results even further. Shortage in availability might be a limiting factor for their widespread use.

Uruguayan experience with cryopreserved arterial homografts

INTRODUCTION

We analyzed the Uruguayan experience with cryopreserved arterial homografts. We studied 55 medical records in the period from June 9, 2000 to April 7, 2007, including 41 from males and 14 from females, ranging from 36-78 years of age. The clinical indications were as follows: Group 1, revascularization of infrainguinal atherosclerotic occlusive disease by bypass due to the lack of availability of a suitable vein (n = 35); Group 2, substitution of an infected prosthetic grafts (n = 15); and Group 3, arteriovenous fistula (AVF) after failure of previous prosthetic loops by repeated thrombosis and/or infection in the absence of a vein (n = 5).

RESULTS

Among Group 1, primary and secondary patency rates were 61% and 71%, respectively at 1 year with 15 complications, 3 infections, 8 thromboses, 2 aneurysms, 1 homograft degradation, and 1 death related to surgery. Among Group 2, the primary and secondary patency rates were 71% and 79%, respectively, at 1 year with 6 patients experiencing complications. Group 3 did not have complications with a primary patency rate of 67% at 1 year.

CONCLUSIONS

The use of cryopreserved arterial homografts is a valid, accessible, and safe alternative in complicated vascular situations. In our country, it is a technology to consider for patients with critical limb ischemia, when the risk of a major amputation is high and it is not possible to have a suitable vein or prosthetic bypass. It can be an excellent alternative for the substitution of infected synthetic bypasses, especially to substitute in situ for an infected aortic graft.

Cold-stored Venous Allografts in the Treatment of Critical Limb Ischaemia

OBJECTIVES

To assess the outcome of cold-stored venous allografts in critically ischemic limbs in patients with no ipsilateral autogenous greater saphenous vein.

DESIGN

A non-randomised, retrospective, single-center study.

METHODS

From September 2000 to June 2006, 46 cold-stored venous allografts obtained during multiorgan harvest were implanted into 44 critically ischaemic limbs of 43 patients. The indication for reconstructions was rest pain (24%) or tissue lost (76%). Sixty-seven percent of procedures were performed as secondary reconstructions, and 61% of veins were anastomosed to tibial or pedal arteries. Thirty-seven percent of patients received prednisone, and 46% tacrolimus as postoperative immunosuppressive therapy. Mean patient follow-up period was 13.3 months (range 1 week to 60 months).

RESULTS

The secondary patency rate for the cohort was 83+/-5.6% at 1 month, 64+/-8.2% at 6 months, 57+/-10.0% at 12 months and 46+/-10.7% at 24 months. Limb salvage rate was 96+/-3.1% at 1 month, 78+/-6.9% at 6 months, 71+/-8.1% at 12 months and 50+/-11.8% at 24 months.

CONCLUSION

Cold-stored venous allografts are an alternative conduit for limb salvage procedures when ipsilateral autogenous vein is unavailable.

Treatment of severe infrapopliteal vascular disease using a novel atherectomy device: a case report

We report two first in man cases of percutaneous revascularization for severe intrapopliteal arterial disease using the novel PV atherectomy device.

[Surgical management of peripheral arterial disease. Operative methods and results]

Various operative and interventional methods are available to treat patients with peripheral arterial disease (PAD). The selection of the appropriate therapy should be made after a careful review of the patient's general condition, the morphology of the arterial occlusion, the risk of possible complications, and the likelihood of long-term success for each type of treatment. The different procedures complement one another in their technical possibilities and their risk profile The combination of surgical and interventional methods offers new therapeutic possibilities. The different surgical procedures and their long-term outcome are presented in this publication.

Systematic review of preservation methods and clinical outcome of infrainguinal vascular allografts

OBJECTIVE

We systematically reviewed clinical studies on the use of venous and arterial allografts for infrainguinal revascularization. We attempted to find evidence for the best infrainguinal vascular allograft by a systematic review of the available literature.

METHODS

An electronic search of the MEDLINE, EMBASE, and Cochrane databases was used to determine key articles from studies on the different types of vascular allografts used in infrainguinal reconstruction from 1966 to 2004. Articles were independently reviewed by using previously defined inclusion and exclusion criteria. Study results were gathered with cumulative primary patency as the primary end point. Secondary end points were major complications, graft disintegration, and major limb loss. Quantitative analysis was performed on the prospective randomized trials, and linear regression analysis was performed on cumulative primary patency. Fontaine's classification system was applied.

RESULTS

No systematic review of randomized controlled trials was found. Five randomized controlled trials, 3 prospective cohort or case series, and 15 retrospective case series with 3,837 vascular allografts were found. Methods of allograft preservation were cryopreservation (5 studies), cold storage (3 studies), and glutaraldehyde preservation of human umbilical veins (15 studies). One-year cumulative primary patency rates were 13% to 79% for cryopreservation, 63% to 80% for cold storage, and 40% to 91% for glutaraldehyde. The weighted mean 1-year cumulative primary graft patency rate was 41% for cryopreservation, 71% for cold storage, and 70% for glutaraldehyde allografts. Four randomized trials on femoropopliteal bypasses demonstrated higher patency rates of glutaraldehyde-preserved human umbilical veins than polytetrafluoroethylene grafts. Statistical heterogeneity between studies (I(2) = 91.4%) was too high to perform a formal meta-analysis. The rate of major limb loss was 20% to 58% for cryopreservation, 10% to 69% for cold storage, and 0% to 65% for glutaraldehyde, and the percentage of graft disintegration was 2% to 6% for cryopreservation, 4% to 15% for cold storage, and 0% to 11% for glutaraldehyde.

CONCLUSIONS

A firm conclusion could not be made because there were no studies available in which direct comparison was performed between different preservation methods of vascular allografts. In addition, heterogeneity of the individual studies hampered direct comparison of different types of vascular allografts. However, the overall graft performance of glutaraldehyde-preserved human umbilical vein allografts may be superior to that of other vascular allografts.

Meta-analysis of alternate autologous vein bypass grafts to infrapopliteal arteries

BACKGROUND

Several studies have described acceptable results for infrapopliteal bypass surgery that uses an autogenous vein other than the greater saphenous vein but is still no reliable prediction of outcomes. The objective of this study was to use meta-analysis to assess the long-term outcomes after infrapopliteal bypass grafting done with alternate autologous veins.

METHODS

Studies published from 1982 through 2004 were identified from electronic databases and pertinent original articles. Thirty-two series were selected, all of which had used survival analysis and had reported a 1-year graft patency rate, with at least 15 bypasses. An interval success rate was calculated for each month in each series of grafts by using data from life tables, survival curves, and texts. Monthly success rates were combined across series to obtain a pooled estimate of success for each month. Pooled survival curves were then constructed for graft patency and foot preservation.

RESULTS

The 5-year pooled estimates were 46.9% (95% confidence interval [CI] = 35.5%-58.3%) for primary patency, 66.5% (95% CI = 54.9%-78.2%) for secondary patency, and 76.4% (95% CI = 68.0%-84.8%) for foot preservation. These results were far superior to those reported for nonautologous grafts. Intensive duplex surveillance had a favorable impact on graft patency and foot preservation. No publication bias was detected.

CONCLUSIONS

When the greater saphenous vein is unavailable, alternate autologous veins are preferable to other graft materials in bypass surgery to infrapopliteal arteries.