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

Poly(ferulic acid)-hybrid nanofibers for reducing thrombosis and restraining intimal hyperplasia in vascular tissue engineering

Small-diameter blood vascular transplantation failure is mainly caused by the vascular materials' unreliable hemocompatibility and histocompatibility and the unmatched mechanical properties, which will cause unstable blood flow. How to solve the problems of coagulation and intimal hyperplasia caused by the above factors is formidable in vascular replacement. In this work, we have synthesized poly(ferulic acid) (PFA) and prepared poly(ester-urethane)urea (PEUU)/silk fibroin (SF)/poly(ferulic acid) (PFA) hybrid nanofibers vascular graft (PSPG) by random electrospinning and post-double network bond crosslinking for process optimization. The results in vitro demonstrated that the graft is of significant anti-oxidation, matched mechanical properties, reliable cytocompatibility, and blood compatibility. Replacing resected rat abdominal aorta and rabbit carotid artery models with PSPG vascular grafts indicated that the grafts are capable of homogeneous hybrid PFA significantly promoted the stabilization of endothelial cells and the ingrowth of smooth muscle cells, meanwhile stabilizing the immune microenvironment. This research demonstrates the PSPG vascular graft with substantial patency, indicating their potential for injured vascular healing.

The application of tissue-engineered fish swim bladder vascular graft

Small diameter (< 6 mm) prosthetic vascular grafts continue to show very low long-term patency, but bioengineered vascular grafts show promising results in preclinical experiments. To assess a new scaffold source, we tested the use of decellularized fish swim bladder as a vascular patch and tube in rats. Fresh goldfish (Carassius auratus) swim bladder was decellularized, coated with rapamycin and then formed into patches or tubes for implantation in vivo. The rapamycin-coated patches showed decreased neointimal thickness in both the aorta and inferior vena cava patch angioplasty models. Rapamycin-coated decellularized swim bladder tubes implanted into the aorta showed decreased neointimal thickness compared to uncoated tubes, as well as fewer macrophages. These data show that the fish swim bladder can be used as a scaffold source for tissue-engineering vascular patches or vessels.

Bai et al. employ a fish bladder-derived decellularized matrix for the engineering of vascular grafts. The authors show that rapamycin-coated bladder-derived vascular grafts can be implanted as an interposition graft in rats, and that these vascular grafts showed decreased neointimal thickness both in artery and veins.

Amputations versus Salvage: Reconciling the Differences

BACKGROUND

 There are many factors to consider when choosing between amputations versus salvage in lower extremity reconstructive surgery. Postoperative functionality and survival benefit are critical factors when deciding between limb salvage and amputation.

METHODS

 In this review, we present the evidence and the risks and benefits between these two options in the setting of the acute, trauma population and the chronic, diabetes population.

RESULTS

 The trauma population is on average young without significant comorbidities and with robust vasculature and core strength for recovery. Therefore, these patients can often recover significant function with anamputation and prosthesis. Amputation can therefore be the more desirable in this patient population, especially in the case of complete traumatic disruption, unstable patients, high risk of extensive infection, and significant nerve injury. However, traumatic lower extremity reconstruction is also a viable option, especially in the case of young patients and those with intact plantar sensation and sufficient available tissue coverage. The diabetic population with lower extremity insult has on average a higher comorbidity profile and often lower core strength. These patients therefore often benefit most from reconstruction to preserve limb length and improve survival. However, amputation may be favored for diabetics that have no blood flow to the lower extremity, recalcitrant infection, high-risk comorbidities that preclude multiple operations, and those with end stage renal disease.

CONCLUSION

 Many patient-specific factors should be considered when deciding between amputation vs. salvage in the lower extremity reconstruction population.

Endo first is not appropriate in some patients with critical limb ischemia because "bridges are burned"

BACKGROUND

The aims of this study were to determine the effect of failed prior endovascular treatment (EV) on early and midterm outcomes of subsequent lower extremity open surgical (OS) bypass.

METHODS

Patients undergoing infrainguinal bypass for critical limb ischemia (CLI) from January 2008 to December 2011 were retrospectively reviewed. The results after first-line bypass and bypass after failure of EV treatment were compared. A total of 213 patients (65.25% men; average age, 73.30 years) underwent bypass. OS patients were then divided into 2 groups: group 1 consisted of 138 patients who underwent primary OS for CLI without prior EV (control group) and group 2 consisted of 75 patients who had OS after a failed attempt at elective EV for peripheral vascular disease. Of the 213 bypass performed, 34% had a prior infrainguinal failed EV. The primary study end points were early and 1-year major amputations and graft occlusion. The secondary outcomes included early and 1-year mortality and the level of distal revascularization.

RESULTS

Secondary patency and limb salvage rates were significantly better in group 1 up to 1 year (99% vs. 86%; P < 0.001 at 1 month and 95% vs. 76%, P < 0.05 at 12 months, respectively).

CONCLUSIONS

Previous failed EV should be predictive of poor outcome in patients undergoing distal OS for CLI.

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.

Risk factors for lower-extremity vein graft failure

Lower-extremity vein graft failure causes significant morbidity, increases health care costs, and negatively impacts patient quality of life. Identification of risk factors is essential for patient selection, risk factor modification, and identifying individuals who would benefit from more stringent surveillance protocols. Risk factors can be considered as either patient-related or technical. Here we discuss the patient-related risk factors for vein graft failure. Nontechnical factors related to the indication for operation include operation after a previously failed graft, or redo bypass, critical limb ischemia, and infection. Risk factors for vein graft failure are distinct from the risk factors for cardiovascular events. Young age and African American and Hispanic race are risk factors for lower-extremity vein graft failure. Hypercoaguable and inflammatory states also increase risk for vein graft failure. Therapy with statins is indicated in patients with peripheral atherosclerosis and may have beneficial effects on vein graft function, although further studies are needed in this area.

Análise espectral segmentar no seguimento de pacientes revascularizados

CONTEXTO: Pacientes tratados por revascularização arterial (enxertos e angioplastias) nos membros inferiores acometidos por doença arterial oclusiva periférica foram seguidos por até 2 anos pós-tratamento usando ultrassom vascular (análise espectral segmentar, AES). OBJETIVO: Demonstrar que a AES pode ser utilizada no seguimento dos pacientes tratados por doença arterial oclusiva periférica. MÉTODOS: As medidas de AES realizadas foram: velocidade sistólica de pico, índice de pulsatilidade e forma da onda de velocidade de fluxo. Essas foram comparadas em cada paciente no pré e pós-tratamento (com intervalos de 3 meses) para diagnóstico de perviedade. RESULTADOS: Medidas realizadas no pós-operatório nas artérias imediatamente distais aos segmentos tratados mostraram aumento consistente de velocidade sistólica de pico e índice de pulsatilidade com mudanças na forma da onda de velocidade de fluxo de unifásica para bi ou trifásica. A velocidade sistólica de pico e o índice de pulsatilidade aumentaram respectivamente em 92,26 e 98,2% (tratamentos no segmento aorto-ilíaco), em 112,83 e 62,39% (tratamentos no segmento fêmoro-poplíteo) e em 149,08 e 28,8% (tratamentos no segmento poplíteo-tibial). Tais mudanças nos padrões de velocidade de fluxo ocorreram em todos os pacientes e permaneceram quase inalteradas enquanto os tratamentos estivessem pérvios. Quando ocorria falência nos tratamentos (oclusões ou estenoses hemodinamicamente significantes), os parâmetros caíam a níveis similares aos de antes do tratamento. Se a falência do tratamento era corrigida por nova revascularização (enxerto ou angioplastia), os parâmetros de AES voltavam a se comportar como após o tratamento inicial. CONCLUSÃO: A AES pode ser usada no seguimento dos pacientes com revascularização dos membros devido a doença arterial oclusiva periférica, demonstrando tanto a perviedade quanto a falência do tratamento.

Infrainguinal occlusive disease: endovascular intervention is the first line therapy

The preferred treatment of infrainguinal occlusive disease at many centers has undergone a paradigm shift from open bypass to endovascular intervention as the first-line therapeutic modality. Our own experience supports a percutaneous first approach. Though skeptics initially cited lower primary patency rates for angioplasty when compared with bypass, more recent studies have shown favorable secondary patencies nearly challenging that of bypass. The need for repeat endovascular intervention to achieve a higher secondary patency is not a major deterring factor because most procedures are associated with a short hospital stay and a relatively low rate of complication. The risk is low and this complex group of patients can tolerate minimally invasive reinterventions well. The longevity of this patient population is generally short, and consequently less durable outcomes may be acceptable. Patients do require close follow-up with early treatment of restenosis. However, there appears to be a decreased cost of intervention when compared with surgery. Furthermore, the functional outcomes and quality of life appear more optimal with angioplasty. The concern that angioplasty may preclude future surgical intervention by damaging the distal bypass target has not borne true. It is unusual for a percutaneous therapy to eliminate the possibility of a bypass should the endovascular approach not be successful. Finally, advances in techniques and devices may herald improved outcomes because percutaneous therapy in the periphery is still in the early stages of its maturation. Thus, endovascular intervention has become an established, as well as a developed method for treating peripheral arterial occlusive disease and should be considered the first-line therapeutic modality for patients with.lower extremity vascular disease.

Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicentre, randomised controlled trial

BACKGROUND

The treatment of rest pain, ulceration, and gangrene of the leg (severe limb ischaemia) remains controversial. We instigated the BASIL trial to compare the outcome of bypass surgery and balloon angioplasty in such patients.

METHODS

We randomly assigned 452 patients, who presented to 27 UK hospitals with severe limb ischaemia due to infra-inguinal disease, to receive a surgery-first (n=228) or an angioplasty-first (n=224) strategy. The primary endpoint was amputation (of trial leg) free survival. Analysis was by intention to treat. The BASIL trial is registered with the National Research Register (NRR) and as an International Standard Randomised Controlled Trial, number ISRCTN45398889.

FINDINGS

The trial ran for 5.5 years, and follow-up finished when patients reached an endpoint (amputation of trial leg above the ankle or death). Seven individuals were lost to follow-up after randomisation (three assigned angioplasty, two surgery); of these, three were lost (one angioplasty, two surgery) during the first year of follow-up. 195 (86%) of 228 patients assigned to bypass surgery and 216 (96%) of 224 to balloon angioplasty underwent an attempt at their allocated intervention at a median (IQR) of 6 (3-16) and 6 (2-20) days after randomisation, respectively. At the end of follow-up, 248 (55%) patients were alive without amputation (of trial leg), 38 (8%) alive with amputation, 36 (8%) dead after amputation, and 130 (29%) dead without amputation. After 6 months, the two strategies did not differ significantly in amputation-free survival (48 vs 60 patients; unadjusted hazard ratio 1.07, 95% CI 0.72-1.6; adjusted hazard ratio 0.73, 0.49-1.07). We saw no difference in health-related quality of life between the two strategies, but for the first year the hospital costs associated with a surgery-first strategy were about one third higher than those with an angioplasty-first strategy.

INTERPRETATION

In patients presenting with severe limb ischaemia due to infra-inguinal disease and who are suitable for surgery and angioplasty, a bypass-surgery-first and a balloon-angioplasty-first strategy are associated with broadly similar outcomes in terms of amputation-free survival, and in the short-term, surgery is more expensive than angioplasty.

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.

Life-style Modification in Peripheral Arterial Disease

OBJECTIVE

To review the published evidence supporting the use of life-style modification in peripheral arterial disease (PAD).

DESIGN

A systematic search of the medical literature was performed for relevant studies.

MATERIALS

The publications obtained were then searched for randomised clinical trials which reported end-points of mortality or major cardiovascular event rates with various life-style modifications.

RESULTS

Only one randomised controlled trial was found reporting relevant end-points. Other trials were of other end-points such as walking distance or biochemical markers.

CONCLUSIONS

There is a lack of randomised controlled data proving the benefit of life-style modification in improving mortality and reducing cardiovascular events in patients with PAD. Despite this there is sufficient evidence to recommend some life-style modification as part of the overall approach to risk reduction in these patients. There is compelling evidence to support smoking cessation, increased exercise and improved diet.

Dacron femoral-popliteal bypass grafts in good-risk claudicant patients

PURPOSE

To evaluate prosthetic femoral-popliteal (FP) grafts as bypass conduits in favorable patients with refractory calf claudication.

SETTING

University-affiliated urban teaching hospital.

METHODS

Cohort study of patency of 6-mm Dacron FP grafts used to treat patients with medically refractory calf claudication meeting the following criteria: nonsmoker; above-knee popliteal artery as an appropriate target vessel; > or =2-vessel tibial outflow; and postoperative anticoagulation and antiplatelet therapy. End points included primary and secondary FP graft patency, need for and outcome of subsequent intervention, limb amputation, and survival.

RESULTS

From January 1998 through March 2001, 92 patients underwent 100 Dacron bypass grafts for medically refractory claudication. All underwent serial postoperative graft surveillance using duplex ultrasound. Using the Society for Vascular Surgery/International Society of Cardiovascular Surgery criteria life-table, primary patency was 84%, assisted primary patency was 88%, and secondary patency was 90% at 5 years. Two patients (2%) died during a mean follow-up period of 49 months (range 30 to 68). No limbs required amputation. Among 9 limbs in which Dacron FP bypass failed, 8 underwent subsequent successful autogenous bypass to the popliteal artery.

CONCLUSION

In highly selected subjects with favorable features known to increase the likelihood of prosthetic graft patency, prosthetic FP grafts function well. Such patients undergo a simpler, more straightforward procedure than when autogenous FP bypass is performed. Subsequent success of autogenous FP repeat bypass suggests that previous prosthetic FP bypass does not threaten lower-extremity arterial outflow.

Risk factors for autogenous infrainguinal bypass occlusion in patients with prosthetic inflow grafts

OBJECTIVE

In patients with prosthetic inflow (PI) grafts the proximal anastomosis of autogenous infrainguinal bypass (AIB) can be placed on the PI or on a distal native vessel in the groin. This study was performed to determine the effect of placement of an AIB proximal anastomotic site in a patient with ipsilateral PI.

METHODS

Patients undergoing AIB and PI between January 1990 and July 2002 were included in the study. They were classified into two groups on the basis of location of the proximal anastomosis. In group 1 the AIB proximal anastomosis was placed on the PI in the groin, whereas in group 2 the AIB proximal anastomosis was placed on a distal native groin artery. Patency, limb salvage, and patient survival in the two groups were calculated with the Kaplan-Meier method. The Cox proportional hazards model was used to determine independent risk factors affecting AIB patency.

RESULTS

Two hundred twenty-nine patients underwent AIB and PI. In group 1, 23 AIBs became thrombosed concurrent with 26 PI occlusions, and in group 2, 7 AIBs became thrombosed concurrent with 36 PI occlusions (P <.001). Five-year assisted primary patency, limb salvage, and patient survival in groups 1 and 2 were 50% and 75% (P <.001, log-rank test), 78% and 90% (P =.005, log-rank test), and 56% and 69% (P = NS, log-rank test), respectively. Factors independently associated with AIB occlusion are hypertension (hazard ratio [HR], 3.41; 95% confidence interval [CI], 1.65-7.05; P =.001), postoperative warfarin sodium therapy (HR, 1.86; 95% CI, 1.07-3.23; P =.03), continued smoking (HR, 1.72; 95% CI, 0.93-3.18; P =.08), AIB arising from PI (HR, 2.38; 95% CI, 1.35-4.18; P =.003), and PI occlusion (HR, 3.70; 95% CI, 2.15-6.36; P <.001).

CONCLUSION

A proximal AIB anastomosis located directly on the PI is an independent risk factor for decreased AIB patency of equal or greater importance than current smoking, hypertension, or PI occlusion. The proximal anastomosis of an AIB in a patient with an ipsilateral PI should be placed on a distal native artery.