Redo bypass surgery to the infrapopliteal arteries for critical leg ischaemia

Bioengineering artificial blood vessels from natural materials

Bioengineering an effective, small diameter (<6 mm) artificial vascular graft for use in bypass surgery when autologous grafts are unavailable remains a persistent challenge. Commercially available grafts are typically made from plastics, which have high strength but lack elasticity and present a foreign surface that triggers undesirable biological responses. Tissue engineered grafts, leveraging decellularized animal vessels or derived de novo from long-term cell culture, have dominated recent research, but failed to meet clinical expectations. More effective constructs that are readily translatable are urgently needed. Recent advances in natural materials have made the production of robust acellular conduits feasible and their use increasingly attractive. Here, we identify a subset of natural materials with potential to generate durable, small diameter vascular grafts.

Endovascular Recanalization of the Chronically Occluded Native Superficial Artery After Failed Bypass Graft: Midterm Results

PURPOSE

To evaluate the safety, effectiveness, and outcomes of endovascular recanalization of chronic total occlusion (CTO) of the superficial femoral artery (SFA) in patients with critical limb ischemia (CLI) after failed surgical bypass graft.

METHODS

Endovascular recanalization of SFA CTO was performed for 26 consecutive CLI patients with failed bypass grafts from 2016 to 2020. Patient demographics, bypass and lesion characteristics, procedural data, technical, and clinical outcomes were evaluated.

RESULTS

The technical success rate was 96.2% (25/26). Retrograde arterial access was used in 16 (61.6%) patients. Additional tibial and iliac angioplasty was performed in 15 and 2 patients, respectively. Fifteen complications occurred in 10 patients, including thrombosis, embolism, vessel rupture, dissection, arteriovenous fistula, and pseudoaneurysm. Pain relief and wound healing were achieved in 22 patients. The primary, assisted primary, and secondary patency rates were 95.5%, 100%, and 100% at 6 months, 81.8%, 95.5%, and 100% at 12 months, and 76.7%, 82.7%, and 87.5% at 24 months, respectively. By univariate analysis, hyperlipidemia (hazard ratio = 7.82; 95% CI: 1.27-48.04, P = .026) was found to be the only significant risk factor related to primary patency loss. Amputation-free survival and limb salvage rates were 100% and 100% at 6 months, 100% and 100% at 12 months, and 87.1% and 93.8% at 24 months, respectively.

CONCLUSIONS

Endovascular recanalization of SFA CTO in CLI patients with graft failures is effective with high technical success rates. Acceptable limb salvage and amputation-free survival rates make this technique a reasonable alternative to repeat surgery for high-risk patients.

Endovascular Relining of Chronically Occluded Infrainguinal Venous Bypass Grafts

BACKGROUND

Treatment of chronically occluded infrainguinal venous bypass grafts in patients presenting with recurrent chronic limb threatening limb ischemia (CLTI) represent a clinical challenge. Recent case reports have suggested the use of endovascular recanalization techniques without preceding thrombolysis. This study assesses feasibility and mid-term outcomes of this technique.

RESULTS

A retrospective review of 5 consecutive patients (3 men, 2 women, mean age 70 ± 5 years) presenting with chronic venous bypass graft occlusion and recurrence of CLTI during 1 year was performed. Patients were treated with relining of the bypass grafts. Patients were followed up at median 26 (6-36) months. All patients were treated successfully with restoration of flow in the grafts using recanalization and relining technique without thrombolysis. In 4 patients, a Viabahn stentgraft (SG) was used with the addition of interwoven nitinol stents (INS) in 3. In 1 patient, the graft was treated with INS without the addition of a stentgraft. No peripheral embolization was encountered during the procedures. One patient occluded the relined grafts after 6 months. The remaining 4 grafts were all patent at 24-month follow-up. A total of 6 reinterventions (in 3 patients) were performed to reach 80% secondary patency.

CONCLUSIONS

This case series demonstrate feasibility and promising mid-term results, from relining of chronically occluded infra-inguinal venous bypass grafts using stent grafts, interwoven and bare-metal stents without preceding thrombolysis. The technique could be an alternative treatment option in the treatment of these challenging cases.

Fístula arteriovenosa como tratamento adjunto na revascularização arterial do membro em risco

Acute arterial occlusion remains a major challenge for the vascular surgeon. The therapeutic approach depends mostly upon the severity of the tissue injury and the duration of symptoms. Several techniques are available in the current therapeutic arsenal, however, regardless of the technique chosen, postoperative factors frequently observed, such as poor outflow status, or even low graft flow, can contribute negatively to the outcome of revascularization. We describe a case of acute limb ischemia, in the postoperative period of a femoral-tibial bypass, which was occluded due to outflow limitation and high peripheral vascular resistance. The patient underwent a second tibial revascularization combined with construction of an arteriovenous fistula, followed by forefoot amputation and partial skin graft. An energetic approach to the at-risk limb makes it possible to reduce unfavorable outcomes, such as amputation and death, and accelerates recovery of tissues affected by acute ischemia.

Long-Term Results and Risk Analysis of Redo Distal Bypass for Critical Limb Ischemia

BACKGROUND

Distal bypass is the optimal treatment for patients with critical limb ischemia (CLI). However, effectiveness of redo distal bypass (rDB) after failed initial distal bypass (iDB) remains uncertain. This study aimed to analyze long-term results of rDB for CLI.

METHODS

Patients undergoing rDB for CLI from 2009 to 2018 at a single institute were retrospectively reviewed. Operative details, primary and secondary patency, survival rate, major amputation-free rate, and risk factors affecting patency were analyzed. The distal runoff was evaluated using the infrapopliteal Global Limb Anatomic Staging System (GLASS) grade (0 to 4: 0 represents good runoff and 4 represents the poorest runoff).

RESULTS

Of 310 iDB (251 patients), 46 rDB were performed in 44 patients: 27 men, mean age 75 ± 10 years, diabetes mellitus 77%, chronic renal failure with hemodialysis 45%. Only the autologous veins were used in distal bypasses: a great saphenous vein (GSV) in 28 (57%), a small saphenous vein in 13 (27%), an arm vein in 6 (12%), and a superficial femoral vein in 2 (4%). The GSV was used less frequently for rDB than for iDB (57% vs. 90%, P < 0.0001). The infrapopliteal GLASS grade 4 was recognized more in rDB than iDB (76% vs. 60%, P = 0.04). Primary and secondary patency of rDB was 25% and 44% at 1 year and 14% and 29% at 3 years, respectively, which were significantly lower than those of iDB (P < 0.0001). The survival rate after rDB was 68% at 1 year and 53% at 3 years. Freedom from major amputation rate in rDB was 83% at 1 year and 66% at 3 years. Multivariate analysis showed the risk factor influencing on secondary patency was patent duration of the iDB graft (P = 0.012). Secondary patency of rDB was higher in the group of late graft occlusion ≥6 months after iDB (late group) than in the group of early graft occlusion < 6 months after iDB (early group) (94% vs. 9% at 1 year and 75% vs. 5% at 3 years, P < 0.0001). However, freedom from major amputation rate at 3 years was comparable between both groups (71% in the late group vs. 61% in the early group).

CONCLUSIONS

Patency of rDB was significantly lower than that of iDB partly because of less use of the GSV and poorer runoff. Because survival and graft patency after rDB was low, rDB should be a suboptimal treatment especially in patients with early graft occlusion within 6 months after iDB.

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.

Development of a Scoring System for the Prediction of Early Graft Failure after Peripheral Arterial Bypass Surgery

BACKGROUND

An occluded lower limb arterial bypass is associated with poor prognosis for the limb. Currently, no risk assessment method to estimate the risk of early graft failure exists. Aim of this study was to investigate the effect of various potential factors on early graft failure of infrainguinal bypass surgery and to develop a risk-scoring model to predict it.

METHODS

A prospective observational clinical study was performed. One hundred infrainguinal bypass procedures (60 autologous and 40 synthetic grafts), throughout a 3-year period were included. Nearly, 84 patients suffered by chronic limb ischemia, whereas 16 by acute limb ischemia or popliteal aneurysm disease. Various possible factors including demographic data, atherosclerosis predisposing factors, and technical details of the procedure were examined as possible causes of early graft failure. Using a combination of univariable and multivariable analysis techniques, the most significant factors were extracted, and a simple predicting risk-scoring system of early graft failure was calculated.

RESULTS

The overall early graft failure rate was 14%. The factors related to it at a statistically significant level, 0.05, were the female gender, a bypass performed after a previous ipsilateral lower limb angioplasty, a redo procedure on the same limb, and a distal anastomosis at an inframalleolar level (pedal bypass). After internal validation, the FARP₂-predicting scoring system was formed as following: Female gender 1 point (F), bypass after a previous Angioplasty 1 point (A), Redo bypass 1 point (R), and Pedal bypass 2 points (P₂). An overall score equal or greater than 2, provided an early graft failure prediction with sensitivity of 100%, specificity 86%, positive predictive value 54%, and negative predictive value of 100% (area under the receiver operator characteristic curve: 0.959).

CONCLUSIONS

FARP₂ is a simple scoring system for predicting early graft failure after an infrainguinal bypass procedure. Further external validation in larger populations is needed.

Successful endothelialization and remodeling of a cell-free small-diameter arterial graft in a large animal model

The large number of coronary artery bypass procedures necessitates development of off-the-shelf vascular grafts that do not require cell or tissue harvest from patients. However, immediate thrombus formation after implantation due to the absence of a healthy endothelium is very likely. Here we present the successful development of an acellular tissue engineered vessel (A-TEV) based on small intestinal submucosa that was functionalized sequentially with heparin and VEGF. A-TEVs were implanted into the carotid artery of an ovine model demonstrating high patency rates and significant host cell infiltration as early as one week post-implantation. At one month, a confluent and functional endothelium was present and the vascular wall showed significant infiltration of host smooth muscle cells exhibiting vascular contractility in response to vaso-agonists. After three months, the endothelium aligned in the direction of flow and the medial layer comprised of circumferentially aligned smooth muscle cells. A-TEVs demonstrated high elastin and collagen content as well as impressive mechanical properties and vascular contractility comparable to native arteries. This is the first demonstration of successful endothelialization, remodeling, and development of vascular function of a cell-free vascular graft that was implanted in the arterial circulation of a pre-clinical animal model.

Prior failed ipsilateral percutaneous endovascular intervention in patients with critical limb ischemia predicts poor outcome after lower extremity bypass

BACKGROUND

Although open surgical bypass remains the standard revascularization strategy for patients with critical limb ischemia (CLI), many centers now perform peripheral endovascular intervention (PVI) as the first-line treatment for these patients. We sought to determine the effect of a prior ipsilateral PVI (iPVI) on the outcome of subsequent lower extremity bypass (LEB) in patients with CLI.

METHODS

A retrospective cohort analysis of all patients undergoing infrainguinal LEB between 2003 and 2009 within hospitals comprising the Vascular Study Group of New England (VSGNE) was performed. Primary study endpoints were major amputation and graft occlusion at 1 year postoperatively. Secondary outcomes included in-hospital major adverse events (MAE), 1-year mortality, and composite 1-year major adverse limb events (MALE). Event rates were determined using life table analyses and comparisons were performed using the log-rank test. Multivariate predictors were determined using a Cox proportional hazards model with multilevel hierarchical adjustment.

RESULTS

Of 1880 LEBs performed, 32% (n = 603) had a prior infrainguinal revascularization procedure (iPVI, 7%; ipsilateral bypass, 15%; contralateral PVI, 3%; contralateral bypass, 17%). Patients with prior iPVI, compared with those without a prior iPVI, were more likely to be women (32 vs 41%; P = .04), less likely to have tissue loss (52% vs 63%; P = .02), more likely to require arm vein conduit (16% vs 5%; P = .001), and more likely to be on statin (71% vs 54%; P = .01) and beta blocker therapy (92% vs 81%; P = .01) at the time of their bypass procedure. Other demographic factors were similar between these groups. Prior PVI or bypass did not alter 30-day MAE and 1-year mortality after the index bypass. In contrast, 1-year major amputation and 1-year graft occlusion rates were significantly higher in patients who had prior iPVI than those without (31% vs 20%; P = .046 and 28% vs 18%; P = .009), similar to patients who had a prior ipsilateral bypass (1 year major amputation, 29% vs 20%; P = .022; 1 year graft occlusion, 33% vs 18%; P = .001). Independent multivariate predictors of higher 1-year amputation and graft occlusion rates were prior iPVI, prior ipsilateral bypass, dialysis dependence, prosthetic conduit and distal (tibial and pedal) bypass target.

CONCLUSIONS

Prior iPVI is highly predictive for poor outcome in patients undergoing LEB for CLI with higher 1-year amputation and graft occlusion rates than those without prior revascularization, similar to prior ipsilateral bypass These findings provide information, which may help with the complex decisions surrounding revascularization options in patients with CLI.

Tertiary patency as a measure of active revascularization policy for leg salvage

BACKGROUND

An active surgical strategy to save lower limbs of patients with critical leg ischemia includes not only infrainguinal bypass surgery but also repeated surgery when needed. A failed infrainguinal bypass often threatens viability of the patient's legs, at which point a redo bypass procedure with a new graft may be the only alternative to major amputation. We assessed tertiary patency, defined as the whole period of time with a patent infrainguinal graft in a leg, to illustrate future potential of limb salvage surgery after a failed bypass.

METHODS

A total of 593 patients with critical leg ischemia and tissue defects (Fontaine IV) who underwent infrainguinal bypass surgery between January 2000 and December 2005 at our institution were included in this retrospective study.

RESULTS

Secondary and tertiary patency rates were 95 ± 1% and 96 ± 3% at 1 month, 75 ± 2% and 82 ± 2% at 1 year, and 61 ± 2% and 70 ± 3% at 5 years, respectively, p = 0.003. Leg salvage rate was 94 ± 1% at 1 month, 83 ± 2% at 1 year, and 78 ± 2% at 5 years. There was no significant difference between leg salvage and tertiary patency rates, p = 0.281.

CONCLUSION

Tertiary patency rate was higher than the secondary patency rate. This result might reflect active limb salvage surgery with satisfactory results. The absence of a gap between tertiary patency and leg salvage rates indicates the importance of a patent infrainguinal bypass graft to save lower limbs of patients with ischemic tissue defects.

Covalent linkage of heparin provides a stable anti-coagulation surface of decellularized porcine arteries

Establishing thrombosis-resistant surface is crucial to develop tissue-engineered small diameter vascular grafts for arterial reconstructive procedures. The objective of this study was to evaluate the stability and anti-coagulation properties of heparin covalently linked to decellularized porcine carotid arteries. Cellular components of porcine carotid arteries were completely removed with chemical and physical means. Heparin was covalently linked to the decellularized vessels by a chemical reaction of the carboxyl end of amino acids with hydroxylamine sulphate salt and heparin-EDC. Bound heparin contents were measured by quantitative colorimetric assay of toluidine blue staining. The average content of heparin in treated vessels was 35.6 +/- 11.6 mg/cm(2) tissue, which represented 6.21 +/- 2.03 UPS heparin/cm(2) tissue. The stability of heparin linkage was tested by incubating the heparin-linked vessels either in PBS at 37 degrees C or in 70% alcohol at room temperature up to 21 days, showing no significant reduction of heparin content. Anti-coagulation property of bound heparin was determined with a clotting time assay using fresh dog blood. Standardized small pieces of non-heparin-bound vessels were clotted in fresh dog blood within 10 min., whereas all heparin-bound vessels did not form clot during 1-hr observation. In vivo platelet deposition of the vessel was determined with a baboon model of the femoral arteriovenous external shunt and (111)Indium labelling of platelets. There were 1.38 +/- 0.07 x 10(9) and 0.64 +/- 0.11 x 10(9) baboon platelets deposited on the control and heparin-linked vessels, respectively, at 60 min. These data demonstrate that covalent linkage of heparin provides an effective and stable anti-coagulation surface of decellularized porcine carotid arteries. This study may suggest a new strategy to develop tissue-engineered biological vascular grafts, which could be used for human coronary or low extremity artery bypasses.

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.

Evaluation of platelet deposition and neointimal hyperplasia of heparin-coated small-caliber ePTFE grafts in a canine femoral artery bypass model

INTRODUCTION

Bypass graft failure due to acute thrombosis and intimal hyperplasia remains a major challenge in small-diameter vascular prosthetic graft reconstruction. Heparin has been shown to prevent thrombus formation and inhibit intimal antithrombotic in animal studies. In this study, we evaluated the effect of small-caliber heparin-coated expanded polytetrafluoroethylene (ePTFE) grafts on platelet deposition and intimal hyperplasia in a canine model of femoral artery bypass grafting.

METHODS

Nine adult greyhound dogs underwent placement of bilateral femorofemoral artery bypass grafts with ePTFE grafts (4 mm diameter and 7 cm long). In each animal, a heparin-coated ePTFE graft was placed on one side while a noncoated graft was placed on the contralateral side which served as the control. Platelet deposition was measured by autologous (111)indium-labeling and scintillation camera imaging analysis in 24 h. The graft patency was assessed at 4 weeks following the bypass. The effect of intimal hyperplasia was assessed with histological and morphometric analysis.

RESULTS

Platelet deposition on the heparin-coated grafts at 24 h was significantly reduced by 72% as compared to controls (P = 0.001). The patency rate was 44% in control grafts and 89% in heparin-coated grafts. There was a significant reduction of graft intimal hyperplasia at both proximal (0.38 +/- 0.21 mm(2)) and distal (0.19 +/- 0.06 mm(2)) anastomoses in the heparin-coated grafts as compared with proximal (1.01 +/- 0.28 mm(2)) and distal (0.42 +/- 0.01 mm(2)) anastomoses in the untreated control grafts, respectively (P < 0.05). Heparin coating significantly reduced graft neointimal hyperplasia at patent graft anastomoses by 55-72% as compared to controls.

CONCLUSIONS

These data demonstrate that heparin coating of ePTFE significantly reduced early platelet deposition and inhibited anastomotic neointimal hyperplasia. Moreover, small-caliber heparin-coated ePTFE graft significantly increased graft patency in a canine femoral artery bypass model. This may represent a promising treatment strategy for improving the clinical performance of small-caliber prosthetic vascular grafts.

Small-caliber heparin-coated ePTFE grafts reduce platelet deposition and neointimal hyperplasia in a baboon model

PURPOSE

Intimal hyperplasia and graft thrombosis are major causes of graft failure. Heparin prolongs graft patency and inhibits neointimal hyperplasia in animal models. The purpose of this study was to evaluate the effect of a heparin-coated expanded polytetrafluoroethylene (ePTFE) graft on platelet deposition and anastomotic neointimal hyperplasia after aortoiliac bypass grafting in a baboon model.

METHODS

Heparin-coated ePTFE grafts (4-mm diameter) were incorporated into exteriorized femoral arteriovenous shunts placed in five baboons. Platelet deposition was analyzed by measuring the accumulation of indium 111-labeled platelets on the grafts, with dynamic scintillation camera imaging. Eight adult male baboons (mean weight, 9.3 kg) underwent bilateral aortoiliac bypass grafting with ePTFE grafts (4-mm internal diameter). In each animal a heparin-coated ePTFE graft was placed in one aortoiliac artery, and an uncoated graft, which served as the control, was placed in the contralateral aortoiliac artery. All grafts were harvested at 4 weeks, and were analyzed quantitatively for neointimal hyperplasia at graft-vessel anastomoses.

RESULTS

Early platelet deposition on heparin-coated grafts after 1 to 4 hours of ex vivo circuitry was significantly reduced. All the harvested aortoiliac grafts were patent at 4 weeks. There was a significant reduction in neointimal area at both proximal (0.26 +/- 0.11 mm(2)) and distal (0.29 +/- 0.14 mm(2)) anastomoses in the heparin-coated grafts, compared with proximal (0.56 +/- 0.18 mm(2)) and distal (0.63 +/- 0.21 mm(2)) anastomoses in the untreated control grafts (P <.05). In addition, neointimal cell proliferation assayed with bromodeoxyuridine (BrdU) incorporation was reduced in the graft neointima (3.47% +/- 0.43%) in heparin-coated grafts compared with the graft neointima (6.21% +/- 0.59%) in untreated control grafts (P <.05).

CONCLUSIONS

Small-caliber heparin-coated ePTFE grafts significantly reduce platelet deposition and anastomotic neointimal hyperplasia and cell proliferation, without measurable side effects, in baboons. Surface coating with heparin in small-caliber ePTFE grafts is useful for improving prosthetic bypass graft patency.

CLINICAL RELEVANCE

An autologous vein graft is the ideal bypass conduit in peripheral arterial reconstruction; however, many patients who undergo bypass grafting do not have adequate or available autologous vein graft. As a result surgeons often must rely on prosthetic grafts as an alternative conduit in arterial bypass procedures. Clinical outcomes with prosthetic grafts in peripheral arterial reconstruction are generally inferior to those with autologous vein bypass grafts, in part because of anastomotic neointimal hyperplasia. This study evaluated the effect of small-caliber heparin-coated expandable polytetrafluoroethylene (ePTFE) grafts in aortoiliac reconstruction in a baboon model. The study found that heparin-coated ePTFE grafts resulted in less intimal hyperplasia and less platelet deposition after implantation, compared with noncoated control ePTFE grafts.

Redo infrainguinal bypass: factors predicting patency and limb salvage

The increased complexity of redo infrainguinal bypass procedures can result in prolonged operative time and increased morbidity. This review was undertaken to compare outcomes from primary and redo bypass procedures and to identify factors predictive of graft failure and limb loss after redo bypass. All infrainguinal bypasses ( n = 468) from 1995 to 1999 were reviewed. A total of 367 primary bypasses in 317 patients were compared to 101 redo grafts in 84 patients with previously failed bypasses. Risk factors and types of procedures were compared using Student's t-test and the chi(2) test. Patency and limb salvage were compared using life-table analysis. Patients requiring redo bypasses were less likely to have diabetes and end-stage renal disease. Two-year patency (66 +/- 4% primary vs. 55 +/- 7% redo, p = 0.13) and limb salvage (75 +/- 3% primary vs. 72 +/- 6% secondary, p = 0.43) were comparable between primary and redo bypass groups. Female gender was predictive of redo graft failure (2-year patency 73 +/- 8% male vs. 39 +/- 9% female, p = 0.01). Clinical indications that predicted failure of a redo bypass included thrombosis of an autologous graft (1-year patency 71 +/- 7% previous prosthetic vs. 49 +/- 10% previous autologous, p = 0.004), thrombosis of an infrageniculate bypass (2-year patency 65 +/- 10% suprageniculate vs. 46 +/- 9% infrageniculate, p = 0.044), and a limb salvage indication for the primary operation (2-year patency 86 +/- 9% claudication vs. 44 +/- 8% limb salvage, p = 0.008). When a primary bypass fails despite the use of optimal conduit (autologous vein) and an infrageniculate target vessel, the redo bypass has a higher risk of failure, particularly in female patients. Nonetheless, patency and limb salvage rates justify an attempt at revascularization after failed primary bypass.

Meta-analysis of polytetrafluoroethylene bypass grafts to infrapopliteal arteries

CONTEXT

Reports of polytetrafluoroethylene (PTFE) bypass grafting to the infrapopliteal arteries have often used survival analysis of acceptable quality to describe a wide range of long-term results. In theory, these results may be combined if variability between series and time intervals is considered.

OBJECTIVE

Meta-analysis was performed to gain insight into long-term graft patency and foot preservation after PTFE bypass grafting to infrapopliteal arteries.

DATA SOURCE

Studies published from 1982 through 2001 were identified from the PubMed database and pertinent original articles.

STUDY SELECTION

Three investigators selected 43 studies that used survival analysis, reported 2-year patency rates, and included at least 15 bypass procedures. Data extraction and transformation: Based on standard life-tables or survivor curves, an interval success rate was calculated for each month in each series. The monthly success rates were combined across series, enabling construction of pooled survivor curves.

DATA SYNTHESIS

Random-effects meta-analysis yielded 5-year pooled estimates (SE) of 30.5% (7.6%) for primary graft patency, 39.7% (5.5%) for secondary graft patency, and 55.7% (5.0%) for foot preservation. During the entire follow-up, pooled estimates were slightly higher for series of PTFE grafts with adjunctive procedures compared with series of PTFE grafts only. Sensitivity analysis: A simulation using only unfavorable assumptions showed a decrease of less than 5% at 5 years for all outcomes, and smaller differences at subgroup meta-analysis. Funnel plots suggested that publication bias was unlikely.

CONCLUSION

This meta-analysis indicated moderate success for PTFE bypass grafts to infrapopliteal arteries, but the role of adjunctive procedures at the distal anastomosis remains uncertain.

Long-term results of infrageniculate bypass grafting using all-autogenous composite vein

Infrageniculate (below-knee) bypass using all-autogenous composite vein requires multiple incisions, venovenostomy, and prolonged operating time. The purpose of this study was to evaluate the long-term results of this procedure, with comparisons to grafts created from single-segment greater saphenous vein (GSV) or polytetrafluoroethylene (PTFE). A total of 362 consecutive infrainguinal bypass grafts with infrageniculate distal target arteries were created in 283 patients in a single institution between January 1995 and December 2000. Comorbid conditions were common, including diabetes (58%), coronary artery disease (56%), prior lower extremity revascularization (41%), end-stage renal failure (20%), and prior coronary artery bypass grafting (18%). The indication for revascularization was limb salvage in 93% of cases. The grafts were constructed from single segments of GSV (n = 239), from two or more vein segments resulting in an all-autogenous composite graft (n = 61), or from PTFE (n = 62). All-autogenous composite grafts were constructed using segments of ipsilateral or contralateral GSV (n = 49), upper extremity vein (n = 23), superficial femoral vein (n = 7), or lesser saphenous vein (n = 5). Infrageniculate all-autogenous composite vein grafts exhibited similar long-term results to those of GSV grafts, and far superior results to those of PTFE grafts. For patients with available autogenous segments, the all-autogenous composite vein graft is the conduit of choice.