Analysis of Outcomes Following Failed Endovascular Treatment of Chronic Limb Ischemia

Fracture and Fragmentation of Vascular Calcifications by Focused Ultrasound

Peripheral artery disease results in ischemia necessitating interventions such as balloon angioplasty. However, calcified lesions resist balloon and stent expansion, leading to poor outcomes. We hypothesized that focused ultrasound can fracture vascular calcifications and enable balloon angioplasty. In a first experiment, focused ultrasound was applied to ex vivo human calcified plaque specimens to determine its effects based on micro-CT imaging. In a second experiment, ultrasound was applied to an in vitro phantom to evaluate whether the effects enable balloon expansion. Fractures, thinning, and disintegration of calcified sections were observed in 15 of 18 treated human plaque samples. Minor mechanical disruption to soft plaque was found in 33% of samples. In tissue phantoms, n = 10/10 samples were successfully expanded by a water-filled angioplasty balloon with ultrasound applied prior to or during expansion. No controls (n = 0/10) were expanded. These results indicate focused-ultrasound plaque fracture is feasible and may enhance balloon angioplasty.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

To Cross or Not to Cross: Using MRI-Histology to Characterize Dense Collagenous Plaque in Critical Limb Ischemia

Peripheral artery disease (PAD) is caused by atherosclerotic buildup in the lower extremities, leading to obstruction and inadequate perfusion to the peripheral vasculature. Impenetrable plaques initially treated with percutaneous vascular intervention (PVI) have led to worse secondary bypass outcomes and amputation in patients. In this case report, we discuss the importance of using magnetic resonance imaging (MRI) histology in PVI planning in a patient with critical limb ischemia. PVI attempts to recanalize the limb failed because of an impenetrable occlusion in the popliteal artery that was not identified on routine preoperative imaging. Subsequent bypass occluded multiple times eventually requiring an above-knee amputation. An MRI-histology protocol-using ultrashort echo time (UTE) and T2-weighted (T2W) sequences-that was performed prior to the index PVI identified the occlusion as a dense collagen plaque. Histology analysis of the amputated specimen confirmed the MRI finding. This imaging modality offers a novel approach to characterize plaque composition and morphology, thereby identifying lesions at greatest risk of PVI failure and potentially playing an important role in selecting the right candidates for an endovascular-first approach.

Technical Success and Mid-Term Outcomes of Endovascular Revascularization of Tibio-Peroneal Trunk Lesions

Tibio-peroneal trunk (TPT) lesions are usually categorized as ‘complex’ in anatomical classifications, which leads to the perception that endovascular therapy (EVT) will be challenging and the outcome most likely poor. This multicenter, retrospective cohort study investigates the efficacy of the EVT of TPT lesions in patients with chronic limb threatening ischemia (CLTI) or an infrapopliteal bypass at risk. The primary endpoint was limb-salvage. The secondary outcomes were technical success, freedom from clinically driven target lesion revascularization (CD-TLR), overall survival, and amputation-free survival. A total of 107 TPT lesions were treated in 101 patients. At 3 years, the limb-salvage rate was 76.4% (95% CI 66.0–86.8%). Technical success was achieved in 96.3% of cases. The freedom from CD-TLR, amputation-free survival, and overall survival at 3 years were 53.0% (95% CI 38.1–67.9%), 33.6% (95% CI 23.0–44.2%), and 47.7% (95% CI 36.1–59.3%), respectively. Reintervention significantly increased the hazard ratio for amputation by 7.65 (95% CI 2.50–23.44, p < 0.001). Our results show that the EVT of both isolated and complex TPT lesions is associated with high technical success and acceptable limb-salvage rates, with reintervention being a major risk factor for amputation. Moreover, mid-term mortality rate was relatively high. In future revisions of the anatomical grading scales, the classification of TPT lesions as highly complex should be reconsidered.

Could prior endovascular interventions affect the results of lower extremity below the knee autologous vein bypasses?

BACKGROUND

Performing a non-selective primary endovascular approach involves risk of performing ineffective procedures and could compromise future treatments. The objective of this research is to determine if previous failed endovascular intervention could affect bypass results.

METHODS

Retrospective cohort study including 77 below the knee (BTK) bypasses with great saphenous vein (GSV) in patients with critical limb ischemia, carried out between 2008-2018. Primary bypasses (P-BP) were compared with bypasses with history of previous failed endovascular intervention (Secondary bypasses [S-BP]). Primary outcomes included: primary, primary-assisted, and secondary patency, and major amputation-free survival (AFS). The quality of GSV used was evaluated as a potential confounding factor.

RESULTS

Forty-six procedures were P-BP (59.7%) and 31 S-BP (40.3%). The mean follow-up was 35.4 (SD: 31) and 28 (DS: 30) months respectively. Univariate results showed an increased risk of loss of primary patency (HR=2.7), primary-assisted patency (HR=3.1) and secondary patency (HR=3.26) in S-BP (P<0.05). This group also presented a trend towards an increased risk of major amputation (HR=1.6; P>0.05). Suboptimal GSV was used in 29% of S-BP and 15% of P-BP. This factor was identified as confounding partially, as it decreased the influence assumed by the history of prior endovascular intervention in the analyzed variables.

CONCLUSIONS

Secondary bypasses show inferior results to primary bypasses in our series. Although the cause could be a prior failed endovascular intervention, the frequent use of suboptimal GSV in this type of patients may also contribute to this effect.

Outcomes of open and hybrid treatments in below the knee pathology for critical limb threatening ischemia

INTRODUCTION

The optimal management of below the knee pathology remains one of the most challenging areas for revascularization in patients presenting with critical limb threatening ischemia. Patients commonly have multilevel lesions and have a high amputation rate and associated mortality. This review aimed to assess the outcomes of below the knee revascularization strategies.

EVIDENCE ACQUISITION

An online literature search of medical databases for original articles or review articles was conducted using mesh terms.

EVIDENCE SYNTHESIS

Bypass surgery remains the gold standard for revascularization with good long-term outcomes with regards to patency, limb salvage, and quality of life but is associated with a higher morbidity than the endovascular approach. Given the increasing frailty of our patients, endovascular treatments have become the preferred strategy with results that are now equal to bypass. Hybrid surgery is an increasingly popular option as it combines the benefits of both endovascular and open surgery and although the evidence base is small the outcomes are encouraging.

CONCLUSIONS

Hybrid surgery offers promising results and could be considered in the treatment of multi-level lower limb arterial disease especially in high-risk patients or those who are not suitable for either open or endovascular techniques as a sole treatment modality.

Asia-Pacific Consensus Statement on the Management of Peripheral Artery Disease: A Report from the Asian Pacific Society of Atherosclerosis and Vascular Disease Asia-Pacific Peripheral Artery Disease Consensus Statement Project Committee

BACKGROUND

Peripheral artery disease (PAD) is the most underdiagnosed, underestimated and undertreated of the atherosclerotic vascular diseases despite its poor prognosis. There may be racial or contextual differences in the Asia-Pacific region as to epidemiology, availability of diagnostic and therapeutic modalities, and even patient treatment response. The Asian Pacific Society of Atherosclerosis and Vascular Diseases (APSAVD) thus coordinated the development of an Asia-Pacific Consensus Statement (APCS) on the Management of PAD.

OBJECTIVES

The APSAVD aimed to accomplish the following: 1) determine the applicability of the 2016 AHA/ACC guidelines on the Management of Patients with Lower Extremity Peripheral Artery Disease to the Asia-Pacific region; 2) review Asia-Pacific literature; and 3) increase the awareness of PAD.

METHODOLOGY

A Steering Committee was organized to oversee development of the APCS, appoint a Technical Working Group (TWG) and Consensus Panel (CP). The TWG appraised the relevance of the 2016 AHA/ACC PAD Guideline and proposed recommendations which were reviewed by the CP using a modified Delphi technique.

RESULTS

A total of 91 recommendations were generated covering history and physical examination, diagnosis, and treatment of PAD-3 new recommendations, 31 adaptations and 57 adopted statements. This Asia-Pacific Consensus Statement on the Management of PAD constitutes the first for the Asia-Pacific Region. It is intended for use by health practitioners involved in preventing, diagnosing and treating patients with PAD and ultimately the patients and their families themselves.

Revascularization of a specific angiosome for limb salvage: does the target artery matter?

Background

To compare clinical outcomes and technical success when direct versus indirect revascularization was achieved after endovascular technique for critical limb ischemia patients with isolated below-the-knee lesions. Fifty patients were included, 34 male and 16 female, their age from 49 to 77 years (mean 63 ±16). All patients were subjected to infra-genicular angioplasty and divided into direct 28 (31 limbs) and indirect groups 22 (24 limbs). Antegrade approach through ipsilateral CFA was used in 48 patients, while retrograde approach through tibiopedal access was used in 2 patients. Diagnostic angiography was done for all cases and duplex ultrasound was used for follow-up.

Results

One hundred thirty-two lesions were encountered, 46 in the ATA, 43 in PTA, 29 in peroneal artery, and 19 in dorsalis pedis artery. Transluminal approach was done in 47 limbs while subintimal cross was used in 8 limbs. After 1 year follow-up, AFS was 75% in the direct group and 67% in the indirect group. Freedom from MALE was 65% in the direct group and 55% in the indirect group. Freedom from MA was 86% in the direct group and 75% in the indirect group.

Conclusion

When there is a choice of target artery for revascularization, preference should be given to the artery directly feeding the wound’s angiosome.

Effects of endovascular first strategy on spliced vein bypass outcomes

OBJECTIVE

Aggressive endovascular interventions for patients without adequate full-length venous conduit have gained popularity. The purpose of this study is to evaluate the outcomes of spliced vein bypass (SVB) as primary treatment versus treatment after failed endovascular intervention (endovascular SVB [ESVB]) for infrainguinal revascularization.

METHODS

A retrospective analysis of a single vascular group's database of all SVBs was queried for demographics, indications, intraoperative details, and outcomes. Exclusion criteria included acute ischemia, aneurysm, dual outflow, bypass revisions, and patients lost to immediate follow-up. SPSS software was used for statistical analysis.

RESULTS

Two hundred thirty-five infrainguinal SVBs were performed between January 2011 and March 2017. There were 182 SVB (77%) and 53 ESVB (23%) with a mean follow-up of 488 days (range, 1-2140). Demographics between the SVB and ESVB groups were similar in all categories recorded: diabetes, hypertension, coronary artery disease, current smoker, chronic obstructive pulmonary disease, hyperlipidemia, and renal disease (P = .29). Indications for bypass were not statistically significant between SVB and ESVB (P = .48). The study included Rutherford class 3 (14 vs 2), class 4 (51 vs 20), class 5 (67 vs 18), and class 6 (50 vs 13). Inflow was grouped into iliac (2.6%), femoral (88%), and popliteal (9.8%). Outflow arteries were grouped into below knee popliteal (14.9%) and infrapopliteal (85.1%). Inflow and outflow arteries, as well as number of spliced pieces per bypass were not different between groups. Major amputation rates were not different between SVB and ESVB for the entire study period. There was no statistical difference with patency outcomes based on Kaplan-Meier survival analysis (P = .84).

CONCLUSIONS

An aggressive endovascular first strategy for treatment of patients without adequate autogenous conduit seems to offer benefit without negatively affecting future bypass options. SVB patency and major amputation rates in this series were not affected by a prior endovascular treatment.

Clinical Assessment of Peripheral Arterial Disease in the Office: What Do the Guidelines Say?

Lower extremity peripheral arterial disease (PAD) is the manifestation of atherosclerotic disease within the lower extremities. The presentation of PAD is diverse ranging from asymptomatic disease to claudication or to debilitating rest pain, nonhealing ulcers, and gangrene. PAD is associated with significant morbidity, mortality, and healthcare costs. Proper diagnosis and management of PAD is important so as to maintain quality of life and reduce the risk of cardiovascular disease and adverse limb events such as amputation. This document provides a comprehensive outpatient approach to the clinical assessment of PAD that includes risk factors, diagnosis, treatment, and follow-up options.

A Comparison of Outcomes After Lower Extremity Bypass and Repeat Endovascular Intervention Following Failed Previous Endovascular Intervention for Critical Limb Ischemia

The optimal approach for repeat revascularization after failed endovascular intervention for critical limb ischemia (CLI) is unclear. This study compared major adverse limb events (MALEs) and major adverse cardiac events (MACEs) between lower extremity bypass (LEB) and repeat endovascular intervention (REI) in patients with prior failed ipsilateral endovascular intervention. American College of Surgeons National Surgical Quality Improvement Program database identified patients undergoing LEB and endovascular intervention for CLI from 2011 to 2014. We compared REI to LEB with single-segment saphenous vein (LEB-SV) and LEB alternative conduit (LEB-alt). Primary outcomes were 30-day MALE and MACE. Multivariate analysis identified independent predictors of MALE and MACE. A total of 1567 revascularizations were performed after failed ipsilateral endovascular intervention (REI: 683 [43.5%], LEB-SV: 570 [36.4%], LEB-alt: 314 [20.0%]). There were 994 and 573 suprageniculate and infrageniculate revascularizations, respectively. Major adverse cardiac events were significantly lower after REI compared to LEB (REI: 15 [2.2%], LEB-SV: 33 [5.8%], LEB-alt: 21 [6.7%], P < .001). Major adverse limb event were not different between groups ( P = .99). In patients with CLI presenting after failed endovascular intervention, REI is associated with lower MACE without an increased risk of MALE compared to LEB. When the anatomy is amenable, REI should be considered a less morbid first option.

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. These guidelines, based on systematic methods to evaluate and classify evidence, provide a cornerstone of quality cardiovascular care.

In response to reports from the Institute of Medicine1 ,2 and a mandate to evaluate new knowledge and maintain relevance at the point of care, the ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) modified its methodology.3 –5 The relationships among guidelines, data standards, appropriate use criteria, and performance measures are addressed elsewhere.5

Perioperative outcomes of infrainguinal bypass surgery in patients with and without prior revascularization

OBJECTIVE

Although an increasing number of patients with peripheral arterial disease undergo multiple revascularization procedures, the effect of prior interventions on outcomes remains unclear. The purpose of this study was to evaluate perioperative outcomes of bypass surgery in patients with and those without prior ipsilateral treatment.

METHODS

Patients undergoing nonemergent infrainguinal bypass between 2011 and 2014 were identified in the National Surgical Quality Improvement Program Targeted Vascular module. After stratification by symptom status (chronic limb-threatening ischemia [CLTI] and claudication), patients undergoing primary bypass were compared with those undergoing secondary bypass. Within the secondary bypass group, further analysis compared prior bypass with prior endovascular intervention. Multivariable logistic regression analysis was used to establish the independent association between prior ipsilateral procedure and perioperative outcomes.

RESULTS

A total of 7302 patients were identified, of which 4540 (62%) underwent primary bypass (68% for CLTI), 1536 (21%) underwent secondary bypass after a previous bypass (75% for CLTI), and 1226 (17%) underwent secondary bypass after a previous endovascular intervention (72% for CLTI). Prior revascularization on the same ipsilateral arteries was associated with increased 30-day major adverse limb event in patients with CLTI (9.8% vs 7.4%; odds ratio [OR], 1.4 [95% confidence interval (CI), 1.1-1.7]) and claudication (5.2% vs 2.5%; OR, 2.1 [95% CI, 1.3-3.5]). Similarly, secondary bypass was an independent risk factor for 30-day major reintervention (CLTI: OR, 1.4 [95% CI, 1.1-1.8]; claudication: OR, 2.1 [95% CI, 1.3-3.5]), bleeding (CLTI: OR, 1.4 [95% CI, 1.2-1.6]; claudication: OR, 1.7 [95% CI, 1.3-2.4]), and unplanned reoperation (CLTI: OR, 1.2 [95% CI, 1.0-1.4]; claudication: OR, 1.6 [95% CI, 1.1-2.1]), whereas major amputation was increased in CLTI patients only (OR, 1.3 [95% CI, 1.01-1.8]). Postoperative mortality was not significantly different in patients undergoing secondary compared with primary bypass (CLTI: 1.7% vs 2.2% [P = .22]; claudication: 0.4% vs 0.6% [P = .76]). Among secondary bypass patients with CLTI, those with prior bypass had higher 30-day reintervention rates (7.8% vs 4.9%; OR, 1.5 [95% CI, 1.0-2.2]) but fewer wound infections (7.3% vs 12%; OR, 0.6 [95% CI, 0.4-0.8]) compared with patients with prior endovascular intervention.

CONCLUSIONS

Prior revascularization, in both patients with CLTI and patients with claudication, is associated with worse perioperative outcomes compared with primary bypass. Furthermore, prior endovascular intervention is associated with increased wound infections, whereas those with prior bypass had higher reintervention rates. The increasing prevalence of patients undergoing multiple interventions stresses the importance of the selection of patients for initial treatment and should be factored into subsequent revascularization options in an effort to decrease adverse events.

Puncturing Plaques

PURPOSE

To test and validate magnetic resonance imaging (MRI) sequences for peripheral artery lesion characterization and relate the MRI characteristics to the amount of force required for a guidewire to puncture peripheral chronic total occlusions (CTOs) as a surrogate for immediate failure of endovascular therapy.

METHODS

Diseased superficial femoral, popliteal, and tibial artery segments containing 55 atherosclerotic lesions were excised from the amputated limbs of 7 patients with critical limb ischemia. The lesions were imaged at high resolution (75 μm³ voxels) with T2-weighted (T2W) and ultrashort echo time (UTE) sequences on a 7-T MR scanner. The MR images (n=15) were validated with micro-computed tomography and histology. CTOs (n=40) were classified by their MR signal characteristics as "soft" (signals indicating fat, thrombus, microchannels, or loose fibrous tissue), "hard" (collagen and/or speckled calcium signals), or "calcified" (calcified nodule signals). A 2-kg load cell advanced the back end of a 0.035-inch stiff guidewire at a fixed displacement rate (0.05 mm/s) through the CTOs, and the forces required to cross each lesion were measured.

RESULTS

T2W images showed fat as hyperintense and hardened tissue as hypointense. Calcium and thrombus appeared as a signal void in conventional MRI sequences but were easily identified in UTE images (thrombus was hyperintense and calcium hypointense). MRI accurately differentiated "hard," "soft," and "calcified" CTOs based on associated guidewire puncture force. The guidewire could not enter "calcified" CTOs (n=6) at all. "Hard" CTOs (n=9) required a significantly higher (p<0.001) puncture force of 1.71±0.51 N vs 0.43±0.36 N for "soft" CTOs (n=25).

CONCLUSION

MRI characteristics of PAD lesions correlate with guidewire puncture forces, an important aspect of crossability. Future work will determine if clinical MR scanners can be used to predict success in peripheral vascular interventions.

Influence of Repeat Intervention on the Risk of Major Amputation After Infrapopliteal Angioplasty for Critical Limb Ischemia

PURPOSE

To assess the influence of repeat intervention on the risk of major amputation after infrapopliteal angioplasty for patients with critical limb ischemia (CLI).

METHODS

A multicenter database of Japanese CLI patients was interrogated to identify patients who underwent balloon angioplasty for isolated infrapopliteal lesions from April 2004 to December 2012. In that time frame, 1298 limbs of 1065 patients (mean age 72±10 years; 739 men) were eligible for this analysis. The prevalence of tissue loss was 76%, with 33% accompanied by infection. The association between repeat intervention and future risk for major amputation was evaluated using a mixed effects logistic regression model. A stratification analysis was also performed with baseline variables. A supplementary analysis compared baseline characteristics between the cases with and without repeat intervention. Hazard ratios (HR) and their 95% confidence intervals (CI) are reported.

RESULTS

Median follow-up was 1.2 years (interquartile range 0.4-2.5), during which time 143 (11.0%) limbs had major amputations and 499 (38.4%) underwent repeat intervention. The mixed effects modeling revealed that repeat intervention was significantly associated with future risk for major amputation (unadjusted HR 3.01, 95% CI 2.05 to 4.41, p=0.001). From the stratification analysis, repeat intervention significantly increased future risk of major amputation in cases with regular dialysis (HR 3.35, 95% CI 2.14 to 5.26, p<0.001), whereas it did not in those without dialysis. The supplemental analysis showed that patients with repeat intervention within 1 year had a higher prevalence of nonambulatory status, regular dialysis, tissue loss, and infection at baseline compared to those without repeat intervention for 1 year.

CONCLUSION

In the patients with CLI due to infrapopliteal lesions, the need for repeat intervention increased the risk of future major amputation. However, this correlation was not applicable to nondialysis patients.

Occluded Superficial Femoral and Popliteal Artery Stents Can Have a Negative Impact on Bypass Target

PURPOSE

To identify whether occluded femoropopliteal stents influence previously available lower extremity bypass (LEB) targets.

METHODS

Among 621 consecutive patients who had undergone stenting of a superficial femoral artery or popliteal artery lesion from January 2009 to December 2013, 30 patients (mean age 69.9±10.2 years; 16 women) were found to have occluded stents. Angiograms before stent placement were analyzed to determine what would have been the optimal distal bypass site, which was compared with the angiogram following stent occlusion.

RESULTS

Seven (22%) limbs lost the bypass target. In one limb, the target changed from above-knee to below-knee popliteal, in 2 limbs from above-knee popliteal to tibial, and in 4 limbs from below-knee popliteal to tibial artery. Eleven (34%) limbs required LEB during follow-up. Chronic obstructive pulmonary disease (p=0.007), chronic renal insufficiency (p=0.026), a popliteal artery stent (p=0.001), and the below-knee popliteal artery as an optimal bypass target (p=0.026) were associated with loss of bypass target following stent occlusion.

CONCLUSION

Superficial femoral artery and popliteal artery stent occlusion can affect target vessels in patients who may require subsequent LEB. This should be considered when performing stenting.

Lower-extremity arterial revascularization: Is there any evidence for diabetic foot ulcer-healing?

The presence of peripheral arterial disease (PAD) is an important consideration in the management of diabetic foot ulcers. Indeed, arteriopathy is a major factor in delayed healing and the increased risk of amputation. Revascularization is commonly performed in patients with critical limb ischaemia (CLI) and diabetic foot ulcer (DFU), but also in patients with less severe arteriopathy. The ulcer-healing rate obtained after revascularization ranges from 46% to 91% at 1 year and appears to be improved compared to patients without revascularization. However, in those studies, healing was often a secondary criterion, and there was no description of the initial wound or its management. Furthermore, specific alterations associated with diabetes, such as microcirculation disorders, abnormal angiogenesis and glycation of proteins, can alter healing and the benefits of revascularization. In this review, critical assessment of data from the literature was performed on the relationship between PAD, revascularization and healing of DFUs. Also, the impact of diabetes on the effectiveness of revascularization was analyzed and potential new therapeutic targets described.

Optimal management of infrainguinal arterial occlusive disease

Peripheral arterial occlusive disease is becoming a major health problem in Western societies as the population continues to age. In addition to risk of limb loss, the complexity of the disease is magnified by its intimate association with medical comorbidity, especially cardiovascular and cerebrovascular disease. Risk factor modification and antiplatelet therapy are essential to improve long-term survival. Surgical intervention is indicated for intermittent claudication when a patient’s quality of life remains unacceptable after a trial of conservative therapy. Open reconstruction and endovascular revascularization are cornerstone for limb salvage in patients with critical limb ischemia. Recent advances in catheter-based technology have made endovascular intervention the preferred treatment approach for infrainguinal disease in many cases. Nevertheless, lower extremity bypass remains an important treatment strategy, especially for reasonable risk patients with a suitable bypass conduit. In this review, we present a summary of current knowledge about peripheral arterial disease followed by a review of current, evidence-based medical and surgical therapy for infrainguinal arterial occlusive disease.

Role of the latest endovascular technology in the treatment of intermittent claudication

Intermittent claudication is a serious symptom in patients with peripheral arterial disease, and severely limits activities of daily living. Conservative treatment (optimal medical therapy and exercise rehabilitation programs) and revascularization procedures (endovascular treatment [EVT] or open bypass surgery) can relieve intermittent claudication. Among these treatment options, EVT has developed dramatically during the past decade, and has enabled physicians to offer less invasive treatment options with increasing durability. EVT for aortoiliac lesions has matured, and its long-term patency now approaches that of open bypass surgery. The latest EVT technologies include drug-eluting stents, stent grafts, drug-coated balloons, and bioresorbable stents. The recently reported patency of stent grafts in the femoropopliteal lesions was comparable with that of the prosthetic bypass graft. In the course of the paradigm shift from bypass surgery to EVT, evidence of any long-term benefit of EVT compared with supervised exercise is still inconclusive. EVT could improve walking performance in the short-term, while supervised exercise could improve walking performance more efficiently in the long-term. Combined treatment with EVT and exercise may offer the most sustainable and effective symptom relief. This paper reviews the relevant literature on the treatment of intermittent claudication, focusing on the latest EVT technologies, and outlines a strategy for achieving long-term benefits.

Clinical efficacy of successful angioplasty in critical ischemia--a cohort study

BACKGROUND

To evaluate the impact of percutaneous angioplasty (PA), objectively assessed with duplex-ultrasound, on 3-year clinical outcome.

METHODS

Thirty-nine patients with atherosclerotic disease successfully treated by PA were included (40 limbs). All patients had critical ischemia with rest pain and ischemic ulcers due to infrainguinal obstructions alone. The patients were submitted to duplex ultrasound examination on the day before and on the first or second day after the procedure. Peak systolic velocities (PSV) were recorded in the anterior tibial, posterior tibial, and fibular arteries at the level of distal third of the leg. All patients were followed for 3 years. Comparison between groups with good and bad results were based on perioperative VPS gradient (GPSV) of the mean of the VPS in the 3 arteries. After 3 years, a good result was defined as a patient having no pain and complete healing of a previous ulcer or minor amputations.

RESULTS

Mean age was 68.5±8.1 years with no difference in demographic characteristics (P>0.05). In 26 cases, the long-term result was good. Healing time ranged from 4 to 130 weeks (median 26.5). Bad long-term results were observed in 12 cases. Two lesions remained unhealed despite patent angioplasty. In 10 cases, a second procedure was carried out (repeat angioplasty in 6 and bypass in 4). TransAtlantic Inter-Society Consensus (TASC) II category A/B registered better clinical success then TASC II category C/D (P<0.05) at 1-year follow-up but not at 3 years (P=0.36). Two-year limb salvage was 92.5%±4.2%. Primary patency was 52.5%±9.5% at 3 years. GVPS was 21.9 cm/sec in the good results group and 24.7 cm/sec in the bad results group (P>0.05). The quality of the initial result, as measured by GPSV, was not associated with long-term success (P>0.05).

CONCLUSIONS

An initially successful procedure indicated by the degree of increased flow is not related to long-term durability and ulcer healing.

Growing impact of restenosis on the surgical treatment of peripheral arterial disease

Background

Patients with peripheral arterial disease often experience treatment failure from restenosis at the site of a prior peripheral endovascular intervention (PVI) or lower extremity bypass (LEB). The impact of these treatment failures on the utilization and outcomes of secondary interventions is poorly understood.

Methods and Results

In our regional vascular quality improvement collaborative, we compared 2350 patients undergoing primary infrainguinal LEB with 1154 patients undergoing secondary infrainguinal LEB (LEB performed after previous revascularization in the index limb) between 2003 and 2011. The proportion of patients undergoing secondary LEB increased by 72% during the study period (22% of all LEBs in 2003 to 38% in 2011, P<0.001). In‐hospital outcomes, such as myocardial infarction, death, and amputation, were similar between primary and secondary LEB groups. However, in both crude and propensity‐weighted analyses, secondary LEB was associated with significantly inferior 1‐year outcomes, including major adverse limb event‐free survival (composite of death, new bypass graft, surgical bypass graft revision, thrombectomy/thrombolysis, or above‐ankle amputation; Secondary LEB MALE‐free survival = 61.6% vs primary LEB MALE‐free survival = 67.5%, P=0.002) and reintervention or amputation‐free survival (composite of death, reintervention, or above‐ankle amputation; Secondary LEB RAO‐free survival = 58.9% vs Primary LEB RAO‐free survival 64.1%, P=0.003). Inferior outcomes for secondary LEB were observed regardless of the prior failed treatment type (PVI or LEB).

Conclusions

In an era of increasing utilization of PVI, a growing proportion of patients undergo LEB in the setting of a prior failed PVI or surgical bypass. When caring for patients with peripheral arterial disease, physicians should recognize that first treatment failure (PVI or LEB) affects the success of subsequent revascularizations.

Cell therapy of peripheral arterial disease: from experimental findings to clinical trials

The age-adjusted prevalence of peripheral arterial disease in the US population was estimated to approach 12% in 1985, and as the population ages, the overall population having peripheral arterial disease is predicted to rise. The clinical consequences of occlusive peripheral arterial disease include intermittent claudication, that is, pain with walking, and critical limb ischemia (CLI), which includes pain at rest and loss of tissue integrity in the distal limbs, which may ultimately lead to amputation of a portion of the lower extremity. The risk factors for CLI are similar to those linked to coronary artery disease and include advanced age, smoking, diabetes mellitus, hyperlipidemia, and hypertension. The worldwide incidence of CLI was estimated to be 500 to 1000 cases per million people per year in 1991. The prognosis is poor for CLI subjects with advanced limb disease. One study of >400 such subjects in the United Kingdom found that 25% required amputation and 20% (including some subjects who had required amputation) died within 1 year. In the United States, ≈280 lower-limb amputations for ischemic disease are performed per million people each year. The first objective in treating CLI is to increase blood circulation to the affected limb. Theoretically, increased blood flow could be achieved by increasing the number of vessels that supply the ischemic tissue with blood. The use of pharmacological agents to induce new blood vessel growth for the treatment or prevention of pathological clinical conditions has been called therapeutic angiogenesis. Since the identification of the endothelial progenitor cell in 1997 by Asahara and Isner, the field of cell-based therapies for peripheral arterial disease has been in a state of continuous evolution. Here, we review the current state of that field.

Predictors and outcomes of restenosis following tibial artery endovascular interventions for critical limb ischemia

OBJECTIVE

Restenosis following tibial artery endovascular interventions (TAEIs) is thought to be benign but is not well characterized. This study examines the consequences and predictors of recurrent stenosis of TAEIs for critical limb ischemia.

METHODS

All TAEIs for critical limb ischemia performed between 2004 and 2010 were retrospectively reviewed. Restenosis was detected by noninvasive imaging and angiography when indicated. Restenoses were identified and the limb outcomes recorded. Tibial reinterventions were performed only for persistent, worsening, or recurrent tissue loss or rest pain with evidence of recurrence on duplex ultrasound or hemodynamic imaging. The χ test and logistic regression were applied as indicated. One-year patency rates were calculated using the Kaplan-Meier method.

RESULTS

A total of 235 limbs in 210 patients were treated for critical limb ischemia (70% tissue loss, 30% rest pain). Tissue loss included gangrene (49%) and ulcers (51%), and involved the forefoot (80%), the heel (14%), or both (6%). Seventy-eight percent of limbs had Trans-Atlantic InterSociety Consensus C/D lesions, with mean preoperative runoff score of 12. Interventions were isolated tibial (45%) or multilevel (55%) (including tibial). Mean postoperative runoff score improved to 6.6, but restenosis occurred in 96 limbs (41%) at a mean of 4 months. The 1-year primary patency was 59% with a mean follow-up of 9 months. Restenosis presented with a persistent wound (32%), worsened wound (42%), rest pain (16%), or no symptoms (10%). A repeat TAEI was performed in 42 (44%), major amputation in 26 (27%), open bypass in 20 (21%), and observation in eight (8%). The overall amputation rate was 13%, but limb loss was significantly higher in patients with restenosis (n = 26 [27%]) than in patients with no restenosis (n = 5 [4%]; P < .001). Patients with restenosis and tissue loss were more likely to have presented with gangrene (63% vs 38%; P = .0003) but had comparable wound distribution (P = NS). There was a trend toward a higher restenosis rate in patients with renal insufficiency (odds ratio, 5.57; P = .08), but this was unaffected by diabetes, statin therapy, or smoking (P = NS). The rate of repeat intervention after the first reintervention was 36%, with an 87% overall limb salvage rate.

CONCLUSIONS

TAEIs can be used successfully to treat patients with critical limb ischemia with acceptable limb salvage rates. Special attention should be given to patients with extensive tissue loss or gangrene because they are at risk for early restenosis and subsequent limb loss. Strict wound and hemodynamic surveillance, wound care, and timely reinterventions are crucial to achieve successful outcomes in this patient population. Amputation or alternative revascularization options, when feasible, should be considered in patients with restenosis and tissue loss given the high rate of limb loss with tibial reinterventions.

Predictors of Failure of Endovascular Revascularization for Critical Limb Ischemia

Background and Aims:

To characterize predictors of failure when treating critical limb ischemia (CLI) patients with an endovascular intervention as the first-line strategy.

Patients and Methods:

This retrospective, registry-based study included 217 consecutive patients with 240 chronic critically ischemic limbs treated with infrainguinal percutaneous transluminal angioplasty (PTA) during 2006–2007 at Helsinki University Central Hospital, Finland. The primary outcome measures were death, major (above-ankle) amputation, and the need for surgical re-intervention within 6 months after the primary procedure. The secondary outcome measures were overall major amputation and survival rates as well as the overall need for surgical or any other (surgical or endovascular) type of re-intervention. Predictors of outcome endpoints were identified with a univariate screen, and a Cox regression model was used in the multivariate analysis.

Results:

Compared to ulcer, gangrene was significantly more strongly associated with amputation within 6 months post-procedurally as well as during the whole follow-up period (p ≤ 0.028). The patient's inability to walk upon hospital arrival was a significant predictor of death, amputation and surgical re-intervention. Mediasclerotic ankle-brachial index (ABI) was an independent predictor of amputation as well as endovascular re-interventions.

Conclusions:

The strong predictors of poor outcome after endovascular revascularization for patients with CLI are cardiac morbidity, the inability to ambulate upon hospital arrival, and gangrene as a manifestation of CLI. The risk of amputation seems to be significantly higher for gangrene than for ulcer and this matter should be taken into account in the clinical classifications for CLI.

TGF-β and Smad3 modulate PI3K/Akt signaling pathway in vascular smooth muscle cells

Transforming growth factor-β (TGF-β) is upregulated at the time of arterial injury; however, the mechanism through which TGF-β enhances the development of intimal hyperplasia is not clear. Recent studies from our laboratory suggest that in the presence of elevated levels of Smad3, TGF-β stimulates smooth muscle cell (SMC) proliferation. This is a novel phenomenon in that TGF-β has traditionally been known as a potent inhibitor of cellular proliferation. In these studies we explore the signaling pathways through which TGF-β mediates its proliferative effect in vascular SMCs. We found that TGF-β phosphorylates and activates Akt in a time-dependent manner, and this effect is significantly enhanced by overexpression of Smad3. Furthermore, both chemical and molecular inhibition of Smad3 can reverse the effect of TGF-β on Akt. Although we found numerous signaling pathways that might function as intermediates between Smad3 and Akt, p38 appeared the most promising. Overexpression of Smad3 enhanced p38 phosphorylation and inhibition of p38 with a chemical inhibitor or a small interfering RNA blocked TGF-β-induced Akt phosphorylation. Moreover, TGF-β/Smad3 enhancement of SMC proliferation was blocked by inhibition of p38. Phosphorylation of Akt by TGF-β/Smad3 was not dependent on gene expression or protein synthesis, and immunoprecipitation studies revealed a physical association among p38, Akt, and Smad3 suggesting that activation requires a direct protein-protein interaction. Our findings were confirmed in vivo where overexpression of Smad3 in a rat carotid injury model led to enhancement of p-p38, p-Akt, as well as SMC proliferation. Furthermore, inhibition of p38 in vivo led to decreased Akt phosphorylation and SMC proliferation. In summary, our studies reveal a novel pathway whereby TGF-β/Smad3 stimulates SMC proliferation through p38 and Akt. These findings provide a potential mechanism for the substantial effect of TGF-β on intimal hyperplasia and suggest new targets for chemical or molecular prevention of vascular restenosis.

Diagnosis and treatment of peripheral arterial disease in diabetic patients with a foot ulcer. A progress report of the International Working Group on the Diabetic Foot

The International Working Group on the Diabetic Foot (IWDGF) has produced in 2011 a guideline on the diagnosis and treatment of peripheral arterial disease in patients with diabetes and a foot ulcer. This document, together with a systematic review that provided the background information on management, was produced by a multidisciplinary working group of experts in the field and was endorsed by the IWDGF. This progress report is based on these two documents and earlier consensus texts of the IWDGF on the diagnosis and management of diabetic foot ulcers. Its aim is to give the clinician clear guidance on when and how to diagnose peripheral arterial disease in patients with diabetes and a foot ulcer and when and which treatment modalities should be considered, taking both risks and benefits into account.

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.