Long-term outcome after early infrainguinal graft failure

Treatment of bypass failure in patients with chronic limb threatening ischemia – open surgery vs. percutaneous mechanical thrombectomy

Summary: Background: Lower limb bypass occlusion in patients with chronic limb threating ischemia remains a challenge. We can choose between different treatment options: open surgery, local thrombolysis, thrombectomy/atherectomy devices. In this pilot study, we compare clinical outcomes and treatment costs between open surgery (OS) and percutaneous mechanical thrombectomy (pMTH). Patients and methods: This pilot study represents a retrospective analysis of hospital data of 48 occluded bypasses admitted from 2013 to 2018. Only patients presenting with severe ischemia and recrudescence of symptoms (Rutherford 4–6) were included in the current analysis. Two cohorts of patients were analysed: patients who underwent OS and patients that underwent pMTH. Primary clinical outcomes were one-year cumulative patency and limb salvage rates. Total cost was calculated as a sum of intra- and post-operative costs. To weigh clinical benefits against the economic consequences of OS versus pMTH a cost-effectiveness framework was adopted. Results: We analysed a series of 48 occluded bypasses 17 treated with open surgery and 31 with pMTH. Procedural success was 100% in both groups. When comparing one-year death rates ( p-value = .22) and re-occlusion rates ( p-value = .43), no statistically significant differences were observed between the two cohorts. Mean patency duration in the surgery cohort was significantly shorter ( p-value < .05). Primary patency (OS 41.2% vs. pMTH 48.4%) and limb salvage rate (OS 88.2% vs. pMTH 90.3%) at one year are similar in both groups. The total cost of surgery was substantially higher (OS 10,159€ vs. pMTH 8,401€) Conclusions: This pilot study, although limited to 48 occluded bypasses, demonstrates that endovascular treatment with pMTH is less invasive, less time consuming and less expensive, and produces greater health benefits than traditional OS.

Innovative endovascular approach for limb salvage in critical limb ischemia

In the absence of feasible revascularization, nearly one third of patients with critical limb ischemia experienced major amputation at 6 months. In patients with an independent living status, this decision is difficult to support without exhausting all chances to attain limb salvage and preserve functional autonomy. The present report describes a new procedure of revascularization by performing a full endovascular extra-anatomic femoropopliteal bypass for the treatment of limb-threatening ischemia. The patient presented with extensive tissue loss and a short-term risk of major amputation. She had experienced previous failure of conventional surgical and endovascular revascularization procedures and ligation of proximal femoral artery precluded any further revascularization attempt. Limb salvage was achieved with this endovascular revascularization procedure with complete wound closure. The patient still presents an independent living status and preserved functional autonomy without wound recurrence after a follow-up of more than 5 years.

Gene Therapy for the Extension of Vein Graft Patency: A Review

The mainstay of treatment for long-segment small-vessel chronic occlusive disease not amenable to endovascular intervention remains surgical bypass grafting using autologous vein. The procedure is largely successful and the immediate operative results almost always favorable. However, the lifespan of a given vein graft is highly variable, and less than 50% will remain primarily patent after 5 years. The slow process of graft malfunction is a result of the vein's chronic maladaptive response to the systemic arterial environment, its primary component being the uncontrolled proliferation of vascular smooth muscle cells (SMCs). It has recently been suggested that this response might be attenuated through pre-implantation genetic modification of the vein, so-called gene therapy for the extension of vein graft patency. Gene therapy seems particularly well suited for the prevention or postponement of vein graft failure since: (1) the stimulation of SMC proliferation appears to largely be an early and transient process, matching the kinetics of current gene transfer technology; (2) most veins are relatively normal and free of disease at the time of bypass allowing for effective gene transfer using a variety of systems; and (3) the target tissue is directly accessible during operation because manipulation and irrigation of the vein is part of the normal workflow of the surgical procedure. This review briefly summarizes the current knowledge of the incidence and basic mechanisms of vein graft failure, the vector systems and molecular targets that have been proposed as possible pre-treatments, the results of experimental genetic modification of vein grafts, and the few available clinical studies of gene therapy for vascular proliferative disorders.

Surveillance after distal revascularization for critical limb ischaemia

Patients with critical limb ischaemia (CLI) are usually elderly and suffer from several co-morbidities. The goal of surveillance after both endovascular and surgical revascularization for CLI is not only the protection of re-established distal perfusion and sustained ambulation but also the reduction of systemic atherothrombotic risk and mortality by ensuring continued best medical care. However, preferred format and rhythm of structured follow-up programs have remained controversial, mainly because of lack of compelling evidence. This review aims to summarize and to appraise available information critically. Thereby, it underlines the importance of systematic surveillance after both surgical and endovascular revascularization for CLI. Recent European guidelines are considered and areas of uncertainty are highlighted and discussed. According to currently available literature and recent guidelines, the early duplex scan is justified in all patients undergoing endovascular or surgical distal revascularization for CLI. There is no best level evidence supporting continued long term duplex surveillance of revascularizations with normal findings at early duplex scan, whereas those patients with abnormal early duplex scan or high risk revacularization are likely to benefit from continued duplex surveillance. Regular clinical follow-up is suggested and clinical deterioration should trigger duplex scanning to ensure revascularization patency.

Antithrombotic agents for preventing thrombosis after infrainguinal arterial bypass surgery

BACKGROUND

Peripheral arterial disease (PAD) is frequently treated by either an infrainguinal autologous (using the patient's own veins) or synthetic graft bypass. The rate of occlusion of the graft after one year is between 12% and 60%. To prevent occlusion, patients are treated with an antiplatelet or antithrombotic drug, or a combination of both. Little is known about which drug is optimal to prevent infrainguinal graft occlusion. This is an update of a Cochrane review first published in 2003.

OBJECTIVES

To evaluate whether antithrombotic treatment improves graft patency, limb salvage and survival in patients with chronic PAD undergoing infrainguinal bypass surgery.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched August 2010) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 3).

SELECTION CRITERIA

Randomised, controlled trials; two review authors independently assessed the methodological quality of each trial using a standardised checklist.

DATA COLLECTION AND ANALYSIS

Data collected included patient details, inclusion and exclusion criteria, type of graft, antithrombotic therapy, outcomes, and side effects.

MAIN RESULTS

A total of 14 trials were included in this review; 4970 patient results were analysed. Four trials evaluating vitamin K antagonists (VKA) versus no VKA suggested that oral anticoagulation may favour autologous venous, but not artificial, graft patency as well as limb salvage and survival. Two other studies comparing VKA with aspirin (ASA) or aspirin and dipyridamole provided evidence to support a positive effect of VKA on the patency of venous but not artificial grafts. Three trials comparing low molecular weight heparin (LMWH) to unfractionated heparin (UFH) failed to demonstrate a significant difference on patency. One trial comparing LMWH with placebo found no significant improvement in graft patency over the first postoperative year in a population receiving aspirin. One trial showed an advantage for LMWH versus aspirin and dipyridamol at one year for patients undergoing limb salvage procedures. Perioperative administration of ancrod showed no greater benefit when compared to unfractionated heparin. Dextran 70 showed similar graft patency rates to LMWH but a significantly higher proportion of patients developed heart failure with dextran.

AUTHORS' CONCLUSIONS

Patients undergoing infrainguinal venous graft are more likely to benefit from treatment with VKA than platelet inhibitors. Patients receiving an artificial graft benefit from platelet inhibitors (aspirin). However, the evidence is not conclusive. Randomised controlled trials with larger patient numbers are needed in the future to compare antithrombotic therapies with either placebo or antiplatelet therapies.

Outcome of Lower Limb Distal Bypass in Afro-Caribbean Populations

There is little data on outcome following lower limb bypass surgery in ethnic minorities in the United Kingdom. We looked at the results of distal bypass surgery in Afro-Caribbeans (AFCs) and compared it to caucasians (CAs). Patients undergoing distal bypass between 2004 and 2009 were analyzed. Life table analyses and log rank were used to compare graft patency and amputation-free survival. A total of 86 CA and 39 AFC patients, with a median age of 78 years and 73 years, respectively (P = .01), underwent bypass. There were more women in AFC groups (41.1%) compared to CA group (19.2%, P = .01). Tissue loss as indication for surgery was more in AFC than in CA group (92.3% vs73.9%, P = .03). Primary, primary-assisted and secondary patency rates, and amputation-free survival at 12 months for AFCs compared to CAs (51.3 vs 44.6; 85.2 vs 80.9; 91.2 vs 84.4; and 84.9 vs 75.1). Graft patency after lower limb distal revascularization in AFCs is comparable to CAs.

A personal experience with the influence of diabetes and other factors on the outcome of infrainguinal bypass grafts for occlusive disease

OBJECTIVE

To investigate the influence of diabetes mellitus and other factors on the outcome of all infrainguinal bypass grafts performed for occlusive disease by a single surgeon at a tertiary referral center.

METHODS

The series includes 650 operations in 412 men and 238 women with median ages of 65 and 69 years, respectively. Critical ischemia was the indication for most procedures (n = 553, 85%), but 97 (15%) were done for claudication alone. Nearly half (n = 312, 48%) of the patients were diabetic, and 195 (30%) required insulin. All-autogenous vein was used for 389 grafts (60%). Synthetic or composite materials were employed for the remaining 261 grafts, 91 (35%) of which were entirely above the knee. Perioperative data were recorded contemporaneously and were supplemented by reviewing 558 of the 565 medical records and the Social Security Death Index. Survival, graft patency, and limb salvage were analyzed using logistic regression, Kaplan-Meier estimates and proportional hazards models.

RESULTS

Diabetics were more likely to have critical preoperative limb ischemia (P < .001), elevated serum creatinine (P = .003) or a history of previous coronary intervention (P = .015), lower extremity revascularization (P < .001) or minor amputations (P = .002). The operative mortality rate was 4.8%, and there were 81 graft occlusions (12%) and 49 major amputations (7.5%) during the index hospital admission. Patency was immediately restored in 46 of the 81 occluded grafts, but their secondary patency rates were only 62 +/- 16% at 1 year and 26 +/- 18% at 5 years. Insulin-dependent diabetes was associated with a higher incidence of early amputation (odds ratio, 2.6; 95% confidence interval [CI], 1.4-4.8; P = .004). Overall survival was 52 +/- 4% at 5 years and 25 +/- 5% at 10 years, and there were 175 late graft occlusions (27%), a total of 198 related reoperations and 107 late amputations (16%). The risks for further occlusion and/or major amputation after three or more graft revisions were 65% and 71%, respectively. Insulin-dependent diabetes also was associated with higher late mortality (hazard ratio [HR], 1.5; 95% CI, 1.2-1.8; P = .001) and amputation rates (HR, 1.5; 95% CI, 1.0-2.1; P = .026), but other independent variables like age, elevated serum creatinine, critical preoperative ischemia, synthetic conduits, and previous ipsilateral bypass had at least as much influence as diabetes on survival, graft failure or limb loss.

CONCLUSIONS

Diabetes was one of several factors influencing survival and limb preservation, but it did not adversely affect graft patency. The number of graft revisions was an important predictor of further occlusion or amputation.

The role of established and emerging risk factors in peripheral vascular graft occlusion

Several studies have evaluated the association between established as well as emerging vascular risk factors with peripheral graft occlusion. There is evidence for a link between the risk for graft occlusion and total serum cholesterol, low-density lipoprotein cholesterol and triglyceride levels. The overall effect of smoking shows a 2.35-fold increase in risk of graft failure. Studies involving diabetic patients undergoing peripheral bypass may have failed to detect higher occlusion rates, possibly due to increased morbidity and mortality as well as higher amputation rates even if the graft is patent. Both antiplatelet agents and anticoagulation seem to be effective in the prevention of graft occlusion. Unconvincing data have been published with regards to the effect of hypertension on graft patency. Emerging factors such as fibrinogen, lipoprotein (a), C-reactive protein and homocysteine levels should also be considered when assessing the risk of graft occlusion. More research is needed to prevent graft occlusion due to the obvious clinical relevance, quality of life and cost issues.

Does the timing of reoperation influence the risk of graft infection?

OBJECTIVE

This study compared the incidence and characteristics of graft infection in patients who underwent early vs late revisional surgery of lower extremity arterial bypass grafts.

METHODS

Between 1992 and July 2005, 500 revisional procedures were performed on 198 lower extremity bypass grafts. Patients whose revisions were performed <30 days after the primary bypass were in the early revision (ER) group (n = 99), and those done >30 days after bypass were in the late revision (LR) group (n = 99). Infection was defined as cellulitis with graft exposure or purulence in continuity with a graft that required antibiotics and operation for infection control. Mean follow-up was 60 months (range, 2 to 60 months). Groups were compared using Student's t test.

RESULTS

The ER group included 66 autogenous and 33 prosthetic grafts. The LR group consisted of 53 autogenous and 46 prosthetic grafts. Of the 500 revisional procedures performed, 17 graft infections occurred (3.4%). Twelve (70.6%) were prosthetic grafts and five (29.4%) were autogenous grafts (P = .004). Defining the infection rate per graft rather than per revisional procedure, the ER group had a significantly higher graft infection rate at 11% (11/99) compared with 6.1% in the LR group (6/99; P = .012). The risk of infection for prosthetic grafts was significantly higher within the ER group at 27.3% (9/33) compared with autogenous grafts at 3.1% (2/66; P = .0001). Infection developed in three vein grafts and three prosthetic grafts in the LR group (P = NS). For prosthetic graft revisions only, infection risk was 27.3% (9/33) in the ER group and 6.5% (3/46) in the LR group (P = .005). The most common cultured pathogen was methicillin resistant Staphylococcus aureus (ER, 6/11 vs LR, 3/6; P = NS). Within the ER group, the prevalence of Pseudomonas aeruginosa was significantly higher at 27.3% (3/11) compared with 0% (0/6) in the LR group (P = .04).

CONCLUSIONS

Early revision of lower extremity arterial bypass grafts has a significantly higher risk of graft infection compared with revision >1 month after surgery. Infection will develop in approximately 25% (9/33) of prosthetic grafts that are reoperated on early. If feasible, reoperation should be delayed >1 month for prosthetic grafts needing revision. Endovascular or extra-anatomic interventions should be considered if early revision is mandated in this group.

Smoking and the patency of lower extremity bypass grafts: A meta-analysis

OBJECTIVE

Smoking is the major risk factor associated with the development and progression of peripheral arterial disease (PAD). To establish the best estimate of the effect of smoking, smoking cessation, and the dose-response relationship on the patency of lower extremity bypass grafts, we performed a systematic review.

METHODS

A search of medical articles and reviews relating to the influence of smoking on the patency of arterial reconstructive grafts in patients with PAD was made. Studies considered for inclusion were those that evaluated the influence of smoking on the primary, secondary, or cumulative patency rates of arterial reconstructive surgery in the lower extremities in patients with PAD. Primary data were used to calculate summary estimates with standard meta-analysis techniques.

RESULTS

The 29 eligible studies included 4 randomized clinical trials, 12 prospective studies, and 13 retrospective studies. The effect of smoking on graft patency in the randomized clinical trials and other prospective studies had a 3.09-fold (2.34 to 4.08; P < .00001) increase in graft failure. A comparison of patency rates among all studies that used autogenous or polyester grafts showed no difference. A clear dose-response relationship was present, with a decreased patency in heavy smokers compared with moderate smokers. Smoking cessation restores patency rates toward the never smokers group.

CONCLUSION

Continued smoking after lower limb bypass surgery results in a threefold increased risk of graft failure. Smoking cessation, even if instigated after the operation, restored graft patency towards the patency of never smokers. These results indicate that adequate smoking cessation strategies in patients eligible for lower limb bypass surgery are of utmost importance.

A randomized prospective study of valvulotome efficacy in in situ reconstructions

OBJECTIVES

To compare the efficacy of valvulotomes during in situ bypass surgery.

DESIGN

A randomized prospective blinded study.

MATERIALS AND METHODS

Thirty PAD patients scheduled for infrainguinal greater saphenous vein bypass were randomized to use of adjustable or fixed valvulotomes for valve destruction. Valvulotomy was performed after construction of the proximal anastomosis. The efficacy of valve destruction was determined by angioscopy after completion of the distal anastomosis by a separate blinded examiner.

RESULTS

A total of 123 valves were evaluated, 61 after use of an adjustable and 62 with a fixed valvulotome. There was no difference ( p = .88) in number of retained valves between the two groups ( n = 16, 17, respectively). The majority of incompletely destroyed valves were found in the proximal parts of the graft (46%, 13 out of 28). The primary patency at 30 days was 100 and 79%, respectively, p = .09).

CONCLUSIONS

No significant difference in efficacy between valvulotomes was found. Both types tend to miss a large proportion of proximal valves.

Timing of Pedal Bypass Failure and Its Impact on the Need for Amputation

Although the utility of dorsalis pedis (DP) bypass for limb ischemia has been well established, the fate of limbs with a failed bypass to the DP artery remains unclear. Data of all patients undergoing DP bypass grafting within a 12-year period from two university hospitals' vascular registries were retrospectively reviewed. Outcomes of early (<30 days) and delayed graft failure (>30 days) were examined. The Student's t-test and chi-squared test were used for univariate analysis; patency rates and patient survival were calculated using the Kaplan-Meier product limit method. Of 1434 DP bypass grafts, 277 (19.3%) failed grafts were identified. Sixty five (4.5%) grafts failed early (within 30 days of surgery) and 212 (14.8%) failed late at a mean time of 15.3 months (range, 1.5-105 months) after initial bypass. Of the 65 limbs with early graft failure, 28 (43.1%) proceeded directly to amputation and 20 underwent additional revascularization attempts, but limb salvage was achieved in only 7 patients; in 45 (69.2%) patients no further revascularizations were attempted. Seventy-four (34.9%) patients with late graft failure underwent redo revascularization. Thirty-nine (52.6%) had their limb saved with graft revision, but 35 patients (47.3%) ultimately lost their limb. In 138 patients with late graft failure (65.1%) no further revascularization attempts were performed. Sixty-two (44.9%) required major amputation. Overall, 49.8% of patients with failed pedal grafts ultimately suffered limb loss. Early graft failure resulted in a significantly higher rate of major amputation that did late graft failure (63.1% vs. 45.8%, respectively; p = 0.015). These results indicate that early occlusion of pedal bypass often leads to immediate major amputation and interventions to maintain graft patency in this setting are often futile. Late failure of pedal bypass is associated with a lower likelihood of amputation because of a higher rate of success of bypass revisions and a lower occurrence of critical ischemia with graft failure.

Limb salvage after infrainguinal bypass graft failure

OBJECTIVE

The purpose of this study was to examine the outcome of patients in whom an infrainguinal bypass graft failed.

METHODS

This was a retrospective analysis of consecutive patients undergoing infrainguinal bypass grafting in a single institution over 8 years.

RESULTS

Six hundred thirty-one infrainguinal bypass grafts were placed in 578 limbs in 503 patients during the study period. The indication for surgery was limb-threatening ischemia in 533 patients (85%); nonautologous conduits were used in 259 patients (41%), and 144 (23%) were repeat operations. After a mean follow-up of 28 +/- 1 months (median, 23 months; range, 0-99 months), 167 grafts (26%) had failed secondarily. The rate of limb salvage in patients with graft failure was poor, only 50% +/- 5% at 2 years after failure. The 2-year limb salvage rate depended on the initial indication for bypass grafting: 100% in patients with claudication (n = 16), 55% +/- 8% in patients with rest pain (n = 49), and 34% +/- 6% in patients with tissue loss (n = 73; P <.001). The prospect for limb salvage also depended on the duration that the graft remained patent. Early graft failure (<30 days; n = 25) carried a poor prognosis, with 2-year limb salvage of only 25% +/- 10%; limb salvage was 53% +/- 5% after intermediate graft failure (<2 years, n = 110) and 79% +/- 10% after late failure (>2 years, n = 15; P =.04). Multivariate analysis revealed shorter patency interval before failure (P =.006), use of warfarin sodium (Coumadin) postoperatively (P =.006), and infrapopliteal distal anastomosis (P =.01) as significant predictors for ultimate limb loss.

CONCLUSION

The overall prognosis for limb salvage in patients with failed infrainguinal bypass grafts is poor, particularly in patients with grafts placed because of tissue loss and those with early graft failure.

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.

Antithrombotic agents for preventing thrombosis after infrainguinal arterial bypass surgery

BACKGROUND

Chronic peripheral arterial disease (PAD) is frequently treated by implantation of either an infrainguinal autologous venous or artificial graft. One-year occlusion rates for infrainguinal bypasses vary between 15 and 75%, depending on the site of distal anastomosis, length, quality, and material of the graft, but also on other factors such as proximal inflow and distal outflow conditions. To prevent graft occlusion, patients are usually treated with either an antiplatelet or antithrombotic drug, or a combination of both. Little is known about which drug is optimal to prevent infrainguinal graft occlusion.

OBJECTIVES

To evaluate whether antithrombotic treatment in patients with chronic PAD undergoing infrainguinal bypass surgery improves graft patency, limb salvage and survival by performing a meta-analysis of performed RCTs.

SEARCH STRATEGY

The search strategy was that adopted by the Cochrane Review Group on Peripheral Vascular Diseases. Additional data bases were reviewed (Reference lists of papers resulting from this search, MEDLINE from 1966-onwards and EMBASE from 1980-onwards using the terms 'anticoagulant' and 'arterial surgery'.

SELECTION CRITERIA

The methodological quality of each trial was assessed independently by at least two reviewers using the checklist provided by the Peripheral Vascular Diseases Collaborative Review Group, with emphasis on concealment of randomisation. Each trial was given an allocation score of A (clearly concealed), B (unclear if concealed), or C (clearly not concealed) and a summary score of A (low risk of bias), B (moderate risk), or C (high risk). Trials scoring A were included and those scoring C were excluded. For a trial scoring B, an attempt was made to obtain more information by contacting the author.

DATA COLLECTION AND ANALYSIS

For each trial, the number of patients originally allocated to each treatment group was extracted from the data and an 'intention to treat' analysis performed. Data collection on each trial included inclusion and exclusion criteria, patient details, type of graft, type and dose of antithrombotic therapy used, outcome, and side effects. The treatment and control groups were compared for important prognostic factors and differences described. If any of the above data was not available, further information was sought from the author. However, the heterogeneity between trials could not be tested due to inaccessible data. Data were synthesized by comparing group results.

MAIN RESULTS

The analysis including four trials which evaluated vitamin K antagonists (VKA) versus no VKA indicate, that oral anticoagulation tendentially favours venous but not artificial graft patency as well as limb salvage and survival. Two other studies comparing VKA with aspirin or aspirin/dipyridamole supported evidence for a positive effect of VKA on the patency of venous but not artificial grafts. Subgroup analysis for artificial grafts as performed in one trial showed a favourable effect of antiplatelet agents on synthetic bypasses. In two trials with a relatively small number of patients low molecular weight heparin treatment was associated with a lower incidence of early postoperative graft thrombosis compared to treatment with unfractionated heparin. In one trial infusion of antithrombin concentrate was reported to have a negative effect on intraoperative graft thrombosis necessitating the study to be stopped before termination. Perioperative administration of ancrod was compared to unfractionated heparin showing no benefit of one drug compared to the other.

REVIEWER'S CONCLUSIONS

Patients operated for an infrainguinal venous graft might benefit from treatment with VKA, whereas patients receiving an artificial graft might profit more from platelet inhibitors (aspirin). However, the evidence is not conclusive. Randomised controlled trials with larger patient numbers comparing antithrombotic therapies with either placebo or antiplatelet therapies are called for in the future.

Modifiable patient factors are associated with reverse vein graft occlusion in the era of duplex scan surveillance

OBJECTIVE

Modifiable patient factors that contribute to graft occlusion may be addressed after surgery. To determine risk factors associated with reverse vein graft (RVG) occlusion, we examined the characteristics and duplex scan surveillance (DS) patterns of patients with RVGs.

METHODS

Patients treated with RVG from January 1996 through December 2000 were identified from a prospective registry. The study population consisted of all patients with RVGs performed during the study period with grafts that subsequently occluded. Patients whose grafts remained patent served as age-matched and gender-matched control subjects. The prescribed DS regimen was every 3 months for the first postoperative year and every 6 months thereafter. Early DS failure was defined as having no DS within the first 3 months. Cox proportional hazards analysis was used to compare the two groups. Hazard ratios were calculated.

RESULTS

During the study period, 674 patients underwent RVG. Fifty-five patients with occluded RVGs were compared with 118 with patent RVGs. The follow-up period for occluded grafts was 13.40 +/- 12.59 months and for patent grafts was 32.40 +/- 15.61 months. Dialysis therapy, a known hypercoagulable state, continued smoking, and DS failure were independent factors associated with RVG occlusion. The hazards ratio for dialysis was 6.45 (95% CI, 3.07 to 13.51; P <.001), for current smoking was 4.72 (95% CI, 2.5 to 8.85; P <.001), for hypercoagulable state was 2.99 (95% CI, 1.47 to 6.10; P =.003), and for early DS failure was 2.43 (95% CI, 1.29 to 4.59; P =.006).

CONCLUSION

Continued smoking and failure to undergo DS within the first three postoperative months are modifiable factors associated with RVG occlusion. Smoking cessation and graft surveillance must be stressed to optimize patency of infrainguinal RVGs.

Tissue loss, early primary graft occlusion, female gender, and a prohibitive failure rate of secondary infrainguinal arterial reconstruction

PURPOSE

This study tested the hypothesis that a subset of secondary infrainguinal arterial reconstructions show prohibitive failure rates.

METHODS

Records of 79 consecutive patients, 44 men and 35 women, with a mean age of 60 years, who underwent secondary infrainguinal bypass from 1992 to 2000 at the University of Michigan Hospital, were reviewed. Data were analyzed with life-table analysis, logistic regression, and descriptive statistics.

RESULTS

Secondary infrainguinal reconstructions were performed in patients who had undergone earlier ipsilateral bypasses once (n = 35) or twice (n = 44). Among the prior procedures, 68% (n = 54) were done at an institution other than the authors'. Comorbidities included coronary artery disease (72%), tobacco use (77%), and diabetes mellitus (34%), but no patient had hemodialysis-dependent renal failure. Disabling claudication, with average ankle brachial index of 0.48, had been the indication for the primary operation in 77% of cases. Femoral-popliteal bypass was the primary procedure in 67%, with a prosthetic graft used in 62%. The mean patency duration of these earlier bypasses was 25 months. The indication for the final bypass was rest pain or tissue loss in 51% of patients, with an average ankle brachial index of 0.37. The most common procedure was a femoral-distal bypass with autologous vein (63%). Mean patency duration of the secondary bypasses was 30 months. Graft failure within 30 days of operation occurred in 22 patients (28%), and amputation was necessitated in 86% of these patients. The presence of rest pain or tissue loss, when accompanied with a history of early prior graft thrombosis in female patients, correlated with worse mean patency rates, recurrent graft failure (P </=.05), and a 94% amputation rate. Men in a similar setting incurred a 57% amputation rate. No association of final patency existed with regard to age, number of prior bypasses, conduit types, tobacco use, or diabetes.

CONCLUSION

Secondary infrainguinal bypasses are associated with an increased rate of graft failure and significant limb loss, particularly in those with a history of rest pain or tissue loss, female gender, and early prior graft failure. More appropriate initial operations in carefully selected patients and aggressive postoperative graft surveillance is speculated to improve these outcomes.

Long-term results of revised infrainguinal arterial reconstructions

PURPOSE

Infrainguinal arterial reconstruction with vein as the conduit has been regarded as the gold standard within the past two decades. However, as many as 20% of patients undergoing these bypass grafting procedures may need secondary interventions for continued patency. Once these reconstructions have been altered, there is concern about the continued patency of these types of revascularizations. In this study, we evaluated the long-term patency of venous reconstructions that had been revised, compared them with those bypass grafting procedures that did not require any intervention, and analyzed long-term outcome.

METHODS

In the past 15 years, 3944 infrainguinal arterial reconstructions were completed with vein as the conduit. A total of 2780 were performed with the vein in situ, and 1164 were performed by using excised vein in a single piece or spliced configuration. Indication, risk factors, and patient demographics were evaluated. Grafts were stratified into revised and unrevised, in situ and excised; excised vein was then stratified into spliced and non-spliced. All grafts were followed with duplex ultrasound scans performed at 3, 6, and 12 months in the first year and every 6 months thereafter. Statistical analysis was performed by using Gehan's generalized Wilcoxon test.

RESULTS

Demographics and indications were similar between groups. Nine percent of all excised veins required some revision, compared with 10% of all in situ reconstructions. When the excised veins were further stratified, 6% of single-piece venous conduits were revised, as opposed to 14% of reconstructions with spliced venous reconstruction. The 5-year patency rates were 67% for revised reconstructions and 78% for unrevised reconstructions (P <.0001). The 5-year patency rate of unrevised in situ bypass grafts was 81%, as compared with 69% for revised in situ reconstruction (P <.0001), and the 5-year patency rate for unrevised excised veins was 68%, with revised excised vein having a 5-year patency rate of 59% (P = not significant).

CONCLUSION

Venous conduits that require revision have a significantly lower long-term patency rate than those that were unrevised. Grafts that require revision may be best suited for aggressive surveillance protocol to maximize long-term patency.

Identification of factors predictive of lower extremity vein graft thrombosis

OBJECTIVE

The objective of this study was to assess the prognostic value of hemodynamic parameters measured with duplex ultrasound scan, together with other important graft and patient characteristics, in predicting lower extremity vein graft thrombosis.

METHODS

A total of 165 lower extremity vein grafts were entered prospectively into a postoperative duplex ultrasound scan surveillance program with examinations performed at 1, 2, 3, 4, 6, 9, 12, 18, and 24 months, and annually thereafter. Duplex scan-derived blood flow velocity measurements were recorded at 1562 patient visits over 7 years. Graft patency was determined after each visit, and an analysis of factors predictive of vein graft thrombosis was performed with Poisson regression.

RESULTS

Thirty-two episodes of first-time graft thrombosis occurred, 23 of which were permanent. One-, 3-, and 5-year secondary graft patency rates were 90%, 86%, and 79%, respectively. In multivariate analyses, duplex scan velocity measurements predictive of lower extremity graft thrombosis included the maximum velocity ratio (Vr) in association with a graft stenosis and the mean graft peak systolic velocity (MGV) within nonstenotic portions of the body of the graft. The incidence of graft thrombosis among grafts without inflow/outflow stenoses, with Vr less than 3.5, and with MGV 50 cm/s or more, was 2.9% per year. Incidence rates were considerably higher among grafts with a of Vr of 3.5 or more (incidence rate ratio = 7.0; 95% CI, 3.4-14.6) or an MGV less than 50 cm/s (incidence rate ratio = 6.5; 95% CI, 3.3-13.1). In grafts without identifiable inflow, outflow, or graft stenoses, there was no association between MGV and the risk of graft thrombosis.

CONCLUSION

Duplex scan velocity measurements are valid predictors of impending graft thrombosis. A Vr of 3.5 or more and an MGV less than 50 cm/s are the best predictive measures. Repair of correctable graft lesions with a Vr of 3.5 or more, or inflow, outflow, or graft lesions associated with an MGV less than 50 cm/s are recommended. Grafts without detectable inflow, outflow, or graft stenoses, regardless of MGV, may be safely followed.

Predictors of outcome when reoperating for early infrainguinal bypass occlusion

The purpose of this study is to identify factors that predict outcome after intervention for early (<30 days) infrainguinal graft thrombosis. We reviewed the medical records, arteriograms, and follow-up studies of patients who underwent infrainguinal bypass for limb salvage between 8/91 and 9/98 and whose graft failed <30 days from the index procedure. Five factors were analyzed: (1) conduit: single segment saphenous vein versus alternative vein or composite conduit (20 vs. 13 patients); (2) repair modality: construction of a new graft at the time of the initial take-back procedure versus local revision and/or thrombectomy alone (12 vs. 21 patients); (3) run-off: good run-off versus poor run-off (20 vs. 13 patients); (4) operative findings: the presence of a correctable problem versus noncorrectable problem (20 vs. 13 patients); and (5) surgical history: previous versus no previous ipsilateral bypass (16 vs. 17 patients). These variables are statistically significant risk factors that can be used in combination to predict outcome. Unless a focal lesion clearly responsible for graft occlusion is found, complete graft replacement should be considered even if the new bypass must be prosthetic. The costs and morbidity of repeated procedures argue for primary amputation when adverse risk factors exist.

Gender does not impact infrainguinal vein bypass graft outcome

BACKGROUND

The percentage of women requiring infrainguinal bypass graft operations continues to increase, whereas the effect of gender on postoperative outcome remains unclear. The purpose of this study was to assess the influence of gender on patient selection and outcome in patients requiring infrainguinal vein bypass grafting procedures.

METHODS

This retrospective study reviewed 217 infrainguinal vein bypass grafts performed over an 8-year period. Medical records and patient interviews were used to determine study measures and outcomes. Gender and multiple covariables affecting patient survival were analyzed; postoperative complications and graft patencies were examined. Bivariate and life-table analyses were conducted, followed by multivariate analysis with the Cox proportional hazards model.

RESULTS

No statistical differences existed between men and women for age, diabetes, cardiac disease, tobacco use, hypertension, stroke, renal disease, or prior contralateral bypass or major amputation. Women were more likely to be black (P =.014) and have a spliced vein graft (P =.035). No differences were noted between the 2 groups for 30-day morbidity rates-except women had more incisional complications (P =.01)-or for survival (P =.45), primary-patency (P =.57), secondary-patency (P =. 79), or limb-salvage rates (P =.40). Multivariate analysis showed that gender had no role in affecting survival rates.

CONCLUSIONS

Gender does not affect graft patency, limb salvage, or survival rates. There should be no introduction of a gender bias into management of infrainguinal occlusive disease.

Above-knee prosthetic femoropopliteal bypass for intermittent claudication. Results of the initial and secondary procedures

OBJECTIVES

[corrected] to report the results of primary and secondary prosthetic above-knee femoropopliteal bypass for intermittent claudication.

DESIGN

a retrospective study in a University hospital.

PATIENTS

one hundred and twelve operations performed in 103 patients (26 women) between January 1990 and June 1997.

METHODS

a comparison of primary assisted patency was made between Dacron and PTFE, between men and women and between operations performed early and late in the study period. Patency of secondary procedures was also studied.

RESULTS

there were no operative deaths. The 5-year survival rate was 81% and equal to that of a demographically matched population. The primary assisted graft patency was 58% after two years. Women had a significantly better graft patency than men (79% vs. 49%). The type of graft and the date of the operation did not influence the outcome. Forty of the 55 occluded grafts were subjected to a redo procedure with a 1-year patency of 29%.

CONCLUSIONS

the results after prosthetic above-knee femoropopliteal bypass procedures are disappointing, and a controversy persists as to whether this operation should be performed for intermittent claudication. The results of secondary procedures are even worse, and perhaps should only be considered in patients suffering critical ischaemia.

Infrainguinal revascularisation in the era of vein-graft surveillance--do clinical factors influence long-term outcome?

OBJECTIVES

To investigate the variables affecting the long-term outcome of infrainguinal vein bypass grafts that have undergone postoperative surveillance.

DESIGN

A retrospective analysis.

PATIENTS AND METHODS

Details of 299 consecutive infrainguinal vein grafts performed in 275 patients from a single university hospital were collected and analysed. All grafts underwent postoperative duplex surveillance. Factors affecting patency, limb salvage and survival rates were examined. These factors were gender, diabetes, hypertension, aspirin, warfarin, ischaemic heart disease, run-off, graft type, early thrombectomy, level of anastomoses and indication for surgery.

RESULTS

The 6-year primary, primary assisted and secondary patency rates were 23, 47, and 57%, respectively. Six-year limb salvage and patient survival were 68 and 45%, respectively. Primary patency was adversely influenced by the use of composite vein grafts. Early thrombectomy was the only factor that significantly influenced secondary patency. Limb salvage was worse in diabetic limbs, limbs with poor run-off and in grafts that required early thrombectomy. Postoperative survival was better in males, claudicants and in patients who took aspirin.

CONCLUSIONS

Although co-morbid factors did not influence graft patency rates, diabetes did adversely effect limb salvage. This study, like others before it, confirms that aspirin significantly reduces long-term mortality in patients undergoing infrainguinal revascularisation.

Warfarin improves the outcome of infrainguinal vein bypass grafting at high risk for failure

OBJECTIVE

Patients with marginal venous conduit, poor arterial runoff, and prior failed bypass grafts are at high risk for infrainguinal graft occlusion and limb loss. We sought to evaluate the effects of anticoagulation therapy after autogenous vein infrainguinal revascularization on duration of patency, limb salvage rates, and complication rates in this subset of patients.

METHODS

This randomized prospective trial was performed in a university tertiary care hospital and in a Veterans Affairs Hospital. Fifty-six patients who were at high risk for graft failure were randomized to receive aspirin (24 patients, 27 bypass grafts) or aspirin and warfarin (WAR; 32 patients, 37 bypass grafts). All patients received 325 mg of aspirin each day, and the patients who were randomized to warfarin underwent anticoagulation therapy with heparin immediately after surgery and then were started on warfarin therapy to maintain an international normalized ratio between 2 and 3. Perioperative blood transfusions and complications were compared with the Student t test or with the chi2 test. Graft patency rates, limb salvage rates, and survival rates were compared with the Kaplan-Meier method and the log-rank test.

RESULTS

Sixty-one of the 64 bypass grafts were performed for rest pain or tissue loss, and 3 were performed for short-distance claudication. There were no differences between the groups in ages, indications, bypass graft types, risk classifications (ie, conduit, runoff, or graft failure), or comorbid conditions (except diabetes mellitus). The cumulative 5-year survival rate was similar between the groups. The incidence rate of postoperative hematoma (32% vs 3.7%; P = .004) was greater in the WAR group, but no differences were seen between the WAR group and the aspirin group in the number of packed red blood cells transfused, in the incidence rate of overall nonhemorrhagic wound complications, or in the overall complication rate (62% vs 52%). The immediate postoperative primary graft patency rates (97.3% vs 85.2%) and limb salvage rates (100% vs 88.9%) were higher in the WAR group as compared with the aspirin group. Furthermore, the cumulative 3-year primary, primary assisted, and secondary patency rates were significantly greater in the WAR group versus the aspirin group (74% vs 51%, P = .04; 77% vs 56%, P = .05; 81% vs 56%, P = .02) and cumulative limb salvage rates were higher in the WAR group (81% vs 31%, P = .01).

CONCLUSIONS

Perioperative anticoagulation therapy with heparin increases the incidence rate of wound hematomas, but long-term anticoagulation therapy with warfarin improves the patency rate of autogenous vein infrainguinal bypass grafts and the limb salvage rate for patients at high risk for graft failure.