Impact of diabetes mellitus on outcomes of superficial femoral artery endoluminal interventions

Nationwide Study of the Outcome of Treatment of Lower Extremity Atherosclerotic Lesions With Endovascular Surgery With or Without Drug Eluting Methods in Patients With Diabetes

CLINICAL IMPACT

This retrospective observational registry trial combines national registries for vascular surgical procedures and diabetes mellitus to clarify results of drug eluting technology in treating diabetic subjects with intermittent claudication or chronic limb threatening ischemia compared to treatment of non-diabetic subjects. As earlier proposed and showed in this trial, there may be an implication for a beneficial treatment efficacy with drug eluting therapy in the diabetic population with PAD compared to the non-diabetic population. A finding worth further exploration.

Dichotomous grouping of peripheral arterial calcification grades: A practical predictor of outcome after endovascular therapy in peripheral arterial disease

BACKGROUND

There is a general agreement that arterial calcification affects the results of endovascular therapy for peripheral arterial disease (PAD). In addition to lacking evidence for their impact, existing calcification scores are complex, and not practical in everyday decision making. The global limb anatomic staging system (GLASS) adopted dichotomous grouping of calcification grades.

OBJECTIVE

In this study we aim to investigate the impact of peripheral arterial calcification scoring after dichotomous grouping on midterm outcomes following endovascular therapy for PAD.

METHODS

This prospective study included all consecutive patients with PAD indicated for endovascular therapy procedure who presented to our tertiary referral center in the period between October 2020 and October 2021. Patients were grouped into Group A (n = 40): with no-to mild calcification (PACSS grade 0,1 and 2), and Group B (n = 53): with severe calcification (PACSS grades 3 and 4). Primary endpoints included technical success rate, primary patency rates, and major adverse limb events rate (MALE) during 2 years of follow-up.

RESULTS

The mean age of the studied cases (n = 93) was 59.31 ± 6.46 years (range 50-75). 70 patients (75.3%) were males, and 23 (24.7%) were females. There was no statistically significant difference between the two groups regarding technical success rate (97.5% in group A versus 94.33% in Group B, p = .457). The Primary patency rate after 1 year was lower in group B (74%) compared to group A (89.7%), but this difference was not statistically significant (p = .059). However, the 2-year primary patency rate was significantly lower in group B compared to group A (64% versus 84.6% respectively, p = .034). MALE rate after 2 years was significantly higher in group B (28%) as compared to group A (10.4%), P = .048. Studying suspected risk factors revealed that severe calcification was more common in patients with ischemic heart disease (34%) and chronic kidney disease (11%), P= .003 and .002 respectively. Logistic regression analysis showed that patients suffered from IHD and those with length of lesion ≥ 5 cm are about five times more likely to have severe calcification compared to their counterparts (OR = 4.875, 95%CI = 1.293-18.383, p = .019, and OR = 4.513, 95% CI = 11.138-17.893, p = .032), respectively.

CONCLUSION

The presence of severe calcification is associated with significantly lower midterm primary patency rates and higher rate of major adverse limb events after endovascular intervention for lower limb denovo arterial lesions.

Targeting smooth muscle cell phenotypic switching in vascular disease

Objective

The phenotypic plasticity of vascular smooth muscle cells (VSMCs) is central to vessel growth and remodeling, but also contributes to cardiovascular pathologies. New technologies including fate mapping, single cell transcriptomics, and genetic and pharmacologic inhibitors have provided fundamental new insights into the biology of VSMC. The goal of this review is to summarize the mechanisms underlying VSMC phenotypic modulation and how these might be targeted for therapeutic benefit.

Methods

We summarize findings from extensive literature searches to highlight recent discoveries in the mechanisms underlying VSMC phenotypic switching with particular relevance to intimal hyperplasia. PubMed was searched for publications between January 2001 and December 2020. Search terms included VSMCs, restenosis, intimal hyperplasia, phenotypic switching or modulation, and drug-eluting stents. We sought to highlight druggable pathways as well as recent landmark studies in phenotypic modulation.

Results

Lineage tracing methods have determined that a small number of mature VSMCs dedifferentiate to give rise to oligoclonal lesions in intimal hyperplasia and atherosclerosis. In atherosclerosis and aneurysm, single cell transcriptomics reveal a striking diversity of phenotypes that can arise from these VSMCs. Mechanistic studies continue to identify new pathways that influence VSMC phenotypic plasticity. We review the mechanisms by which the current drug-eluting stent agents prevent restenosis and note remaining challenges in peripheral and diabetic revascularization for which new approaches would be beneficial. We summarize findings on new epigenetic (DNA methylation/TET methylcytosine dioxygenase 2, histone deacetylation, bromodomain proteins), transcriptional (Hippo/Yes-associated protein, peroxisome proliferator-activity receptor-gamma, Notch), and β3-integrin-mediated mechanisms that influence VSMC phenotypic modulation. Pharmacologic and genetic targeting of these pathways with agents including ascorbic acid, histone deacetylase or bromodomain inhibitors, thiazolidinediones, and integrin inhibitors suggests potential therapeutic value in the setting of intimal hyperplasia.

Conclusions

Understanding the molecular mechanisms that underlie the remarkable plasticity of VSMCs may lead to novel approaches to treat and prevent cardiovascular disease and restenosis.

Adverse Prognosis of Peripheral Artery Disease Treatments Associated With Diabetes: A Comprehensive Meta-Analysis

Many studies have investigated the influence of diabetes mellitus (DM) on outcomes in patients with peripheral artery disease (PAD). We performed a meta-analysis of the outcomes of PAD treatments in DM patients compared with those without DM. Long-term mortality was the primary endpoint. Secondary endpoints were in-hospital/30-day mortality, primary/secondary patency, amputation, and limb salvage. Thirty-one studies reporting 58113 patients were eligible for enrollment. The mean follow-up duration ranged from 1 to 89 months. DM was significantly associated with long-term mortality (relative risk (RR) = 1.67; 95% confidence intervals (CI), 1.43-1.94; P < .001). DM was also associated with significantly lower primary patency (RR = 0.74; 95% CI, 0.58-0.95; P = .001) and secondary patency (RR = 0.80; 95% CI, 0.67-0.96; P = .009). DM is associated with worse outcomes and adverse prognosis of treatment in patients with PAD, and may therefore be a modifiable risk factor for poor prognosis in PAD patients.

Endovascular recanalization of chronic total occlusions of the native superficial femoral artery after failed femoropopliteal bypass in patients with critical limb ischemia

BACKGROUND

Femoropopliteal bypass occlusions are a significant issue in patients with critical limb ischemia and chronic total occlusion of the native superficial femoral artery, which challenges vascular surgeons and interventional radiologists. Performing a secondary femoropopliteal bypass is still considered the standard of care, although it is associated with a higher complication rate and lower patency rate in comparison with primary bypass. Over the past few years, angioplasty has been commonly used, with the development in endovascular technologies, to treat chronic total occlusions of the native superficial femoral artery, with a good technical success rate and clinical prognosis. The purpose of the study is to assess the outcome of endovascular recanalization of chronic total occlusions of the native superficial femoral artery, in patients unfit for surgery with critical limb ischemia after failed femoropopliteal bypass.

RESULTS

A total of 54 patients were treated. 77.8 % of the conduits were PTFE grafts; the remainder were single-segment great saphenous veins. The most common clinical presentation was rest pain. Technical success was achieved in 51 (94.4 %) of 54 limbs. Angiographically, 77.8 % of the lesions were TASC II category D, while 22.2 % were TASC II category C. The average length of the native SFA lesions was 26.8 cm. Clinical success, with improved Rutherford classification staging, followed each case of technical success. The median follow-up value was 5.75 years (IQR, 1.5-7). By Kaplan-Meier survival analysis, primary patency rates were 61 % (± 0.07 SE) at 1 year and 46 % (± 0.07 SE) at 5 years. Secondary patency rates were 93 % (± 0.04 SE) at 1 year and 61 % (± 0.07 SE) at 5 years. Limb salvage rates were 94 % (± 0.03 SE) at 1 year and 88 % (± 0.05 SE) at 5 years.

CONCLUSIONS

The endovascular recanalization of chronic total occlusions (CTO) of the native superficial femoral artery (SFA) after a failed femoropopliteal bypass is a safe and effective therapeutic option in patients unfit for surgery with critical limb ischemia.

Patient and Institutional Costs of Failure of Angioplasty of the Superficial Femoral Artery

BACKGROUND

Debate surrounds the optimal management of superficial femoral artery (SFA) disease. Randomized trial data rarely reflect real world findings, specifically the consequences to the patient of angioplasty failure. We observed the effect of a failed SFA angioplasty on the need for repeated clinic visits, hospital readmissions, imaging requirements, and reinterventions.

METHODS

We reviewed a consecutive series of 148 patients (94 men, median age 72 years) undergoing solely SFA angioplasty over a 2-year period. Patient preangioplasty demographics and 2-year post-PTA follow-up data were collated, including hospital attendances (inpatient/outpatient), further imaging (including radiation exposure) and revascularization attempts. We defined "failed angioplasty" as presence of clinical symptoms with radiological evidence of significant restenosis after an initial successful primary SFA angioplasty.

RESULTS

Fifty-four patients represented with a failed angioplasty (median time of 4 months after index PTA). In this group, failure of index angioplasty resulted in a further 185 restenosis-related clinic visits and a total of 537 bed days of inpatient stay. This group underwent a further 149 imaging events and required a further 34 endovascular revascularization procedures and 12 infrainguinal bypass procedures. These interventions and investigations corresponded to overall effective radiation dose across all patients of 190.69 mSv. Of the cohort of 99 patients who did not have a "failed angioplasty," they required 100 clinic visits, 21 further scans (total radiation dose 6.42 mSv), and 36 bed days of inpatient admission.

CONCLUSIONS

Failed angioplasty results in significant additional consequences for patients and health-care systems. Further work should focus on refining decision-making, providing the right procedure to the right patient at the right time.

Clinical Outcomes after Endovascular Therapy Among Hemodialysis Patients with Peripheral Artery Disease Stratified by the Primary Kidney Disease

OBJECTIVES

The objective of this study was to investigate the clinical characteristics of hemodialysis patients with peripheral artery disease (PAD) and the outcomes after endovascular therapy (EVT) in such patients stratified by the primary kidney disease.

METHODS

This retrospective observational study evaluated 142 consecutive hemodialysis patients with symptomatic PAD who underwent EVT (men: n = 103, age: 74 ± 8 years). Patients were divided into 3 groups in accordance with the reason for hemodialysis: hypertensive nephrosclerosis (HTN [n = 26]), diabetic nephropathy (DN [n = 85]), and chronic glomerulosclerosis (CGN [n = 31]). The primary outcome was major adverse event(s) (MAEs), including target lesion revascularization, major amputation, and all-cause death. Clinical characteristics and outcomes were compared among the 3 groups.

RESULTS

Patients with HTN were older (81 ± 6 years vs. 72 ± 8 years vs. 74 ± 8 years; P < 0.001) and had a shorter hemodialysis vintage (2.4 years vs. 6.8 years vs. 11.2 years; P < 0.001) than those with DN and CGN. Critical limb ischemia (CLI) affected 15 (58%) patients in the HTN group, 52 (61%) in the DN group, and 10 (32%) in the CGN group. Target lesion length was longer in patients with HTN than in those in the other groups (155 ± 101 mm vs. 108 ± 77 mm [DN] vs. 98 ± 76 mm [CGN]; P = 0.020). During a median follow-up period of 372 days (interquartile range, 198-730 days), Kaplan-Meier curve analysis revealed that HTN was associated with an increased risk for MAEs (χ² 11.6; P = 0.003). Furthermore, multivariate Cox regression analysis revealed that CLI, HTN, and B-type natriuretic peptide levels were independent predictors of MAE (hazard ratio 3.91, 2.88, and 1.00; P < 0.001, P < 0.001, and P = 0.001, respectively).

CONCLUSIONS

Among hemodialysis patients with PAD, HTN was associated with an increased risk for MAEs after EVT.

The impact of chronic kidney disease on outcomes following peripheral vascular intervention

BACKGROUND

Patients with chronic kidney disease (CKD) have worsened clinical outcomes following percutaneous coronary intervention; however, limited evidence exists in patients undergoing peripheral vascular intervention (PVI).

PURPOSE

We aimed to assess the effect of CKD on outcomes following PVI for symptomatic peripheral artery disease.

METHODS

Using patients from the LIBERTY 360 study, we compared the rates of 30 day and 1 year major adverse vascular events (MAVE), a composite of all-cause mortality, major amputation, and target vessel/lesion revascularization, between patients with and without CKD (estimated glomular filtration rate less than 60) following PVI. Multivariable adjustment was performed to assess for independent association between CKD and outcomes.

RESULTS

Among 1189 patients enrolled, 378 patients (31.8%) had CKD. At 1 year, patients with CKD had higher rates of MAVE (34.6% vs 25.6%), all-cause mortality (11.9% vs 5.5%), and major amputation (5.9% vs 2.6%) when compared with patients without CKD (all P < .05). After adjustment, patients with CKD had higher risks of 1-year MAVE (HR 1.30, 95% CI 1.04-1.64; P = .023) and all-cause mortality (HR 1.88, 95% CI 1.22-2.91; P = .005) when compared with patients without CKD. There was no statistically significant difference in risk of major amputations (HR 1.70, 95% CI 0.91-3.17; P = .094).

CONCLUSIONS

Despite high procedural success and low amputation rates, patients with CKD remain at greater risk for MAVE and all-cause mortality after PVI. Further research is needed to determine treatment strategies to mitigate substantial mortality risk in this vulnerable population.

Factors affecting patency of arteriovenous fistula following first percutaneous transluminal angioplasty

BACKGROUND

Percutaneous transluminal angioplasty (PTA) has generally replaced surgical procedures to treat arteriovenous fistula (AVF) dysfunction, but the predictors of post-intervention patency are highly variable. This study aimed to determine predictors of primary patency following PTA of dysfunctional AVF.

MATERIALS AND METHODS

Retrospective analysis of first-time PTA of 307 AVF in 307 patients (171 males, mean age 64.3 ± 12.4 years). Demographic, clinical, anatomical and medication variables were reviewed and subjected to univariate and multivariate Cox regression analysis.

RESULTS

The post-intervention primary patency rates at 6, 12, 24, and 36 months were 76.3%, 58.3%, 43.2%, and 38.2%, respectively. The higher aortic arch calcification (AAC) grade patients were older, had higher incidence of comorbidities and cardiomegaly, and younger AVF age, but their dialysis vintage term was shorter and diastolic blood pressure was lower, and the maximum diameter of balloon angioplasty was mostly ≤ 6 mm, and had lower phosphorus level and less calcium-containing phosphate binder use. In multivariate Cox proportional hazard analysis, the presence of higher AAC grade [hazard ratio (95% confidence interval): (1.46 (1.02-2.09); p = 0.037)] and stenosis at upper arm [1.76 (1.16-2.67); p = 0.008] were associated with shorter post-intervention primary patency.

CONCLUSION

In conclusion, higher AAC grade and anatomic factor related to the location of AVF (upper arm) were the important predictors of AVF dysfunction after PTA. These results could assist in tailoring surveillance programs and performing appropriate interventions for risky AVF.

New Innovations and Devices in the Management of Chronic Limb-Threatening Ischemia

As the number of patients afflicted by chronic limb-threatening ischemia (CLTI) continues to grow, new solutions are necessary to provide effective, durable treatment options that will lead to improved outcomes. The diagnosis of CLTI remains mostly clinical, and endovascular revascularization remains mostly balloon-based. Multiple innovative techniques and technologies are in development or in early usage that may provide new solutions. This review categorizes areas of advancement, highlights recent developments in the management of CLTI and looks forward to novel devices that are currently under investigation.

Six-month results of stenting of the femoropopliteal artery and predictive value of interleukin-6: Comparison with high-sensitivity C-reactive protein

OBJECTIVES

To determine the association of pre- and postinterventional serum levels of interleukin-6 and high-sensitivity C-reactive protein at the six-month evaluation of restenosis after stenting of the femoropopliteal artery.

METHODS

Sixty-eight consecutive patients with steno-occlusive femoropopliteal artery disease of Rutherford category III or IV who underwent stent implantation were included. Six-month patency was evaluated with color-coded duplex ultrasound. The association of in-stent restenosis with interleukin-6 and high-sensitivity C-reactive protein levels at baseline, and 24-h postintervention was assessed with a multivariate logistic regression analysis.

RESULTS

In-stent restenosis was found in 15 patients (22.1%) within six months. Interleukin-6 and high-sensitivity C-reactive protein levels were significantly increased at 24-h postintervention compared to their preintervention values (p < 0.001 and p = 0.002, respectively). Interleukin-6 values at baseline (odds ratio, 1.11; 95% confidence interval: 1.00, 1.23; p = 0.044) and 24-h postintervention (odds ratio, 1.04; 95% confidence interval: 1.02, 1.06; p < 0.001) were independently associated with six-month in-stent restenosis. Twenty-four-hour postinterventional high-sensitivity C-reactive protein levels were also found to be related to restenosis (odds ratio, 1.15; 95% confidence interval: 1.04, 1.26; p = 0.006), but high-sensitivity C-reactive protein levels at baseline did not show an independent association with in-stent restenosis (odds ratio, 0.57; 95% confidence interval: 0.35, 1.80; p = 0.667). Smoking, diabetes mellitus, and cumulative stent length were other parameters associated with an increased risk for in-stent restenosis.

CONCLUSIONS

Femoropopliteal artery angioplasty with stent placement induces an inflammatory response. Interleukin-6 is a powerful independent predictor of intermediate-term outcomes for stenting of the femoropopliteal artery, suggesting that its predictive value may be superior to that of high-sensitivity C-reactive protein.

Medial artery calcification increases neointimal hyperplasia after balloon injury

Arterial calcification predicts accelerated restenosis after angioplasty and stenting. We studied the effects of calcification on neointimal hyperplasia after balloon injury in the rat carotid. Arterial calcification was induced by subcutaneous injection of vitamin D₃ or by adventitial application of calcium chloride. After balloon catheter injury, neointimal hyperplasia was significantly increased in rats with medial calcification compared with controls. Neointimal cell proliferation in calcified arteries as assessed by proliferating cell nuclear antigen (PCNA) staining was also higher. In calcified arteries, bone morphogenetic protein 2 (BMP-2)levels were increased at the time of injury suggesting a possible explanation for the altered responses. In vascular smooth muscle cells (SMCs) grown under calcifying conditions , stimulation with BMP-2 significantly increased cell proliferation, however, this did not occur in those grown under non-calcifying conditions. These data suggest that neointimal hyperplasia is accelerated in calcified arteries and that this may be due in part to increased BMP-2 expression in medial SMCs. Treatments aimed at inhibiting restenosis in calcified arteries may differ from those that work in uncalcified vessels.

The Impact of Diabetes and Time on the Atherosclerotic Plaque and Cardiovascular Outcome in Patients Undergoing Iliofemoral Endarterectomy

OBJECTIVE

The incidence of diabetes is rapidly increasing and diabetes is associated with an increased risk of peripheral artery disease. Recent studies have shown a time dependent decline in vulnerable plaque features and secondary cardiovascular events in iliofemoral endarterectomy (IFE) patients. IFE patients with diabetes have a high risk of cardiovascular events. It is not known, however, whether vulnerable plaque features and cardiovascular events reduce over time in IFE patients with diabetes.

METHODS

Between 2003 and 2014, 691 atherosclerotic plaques were obtained by IFE, from 212 patients with and 479 patients without diabetes. Plaques were immunohistochemically stained and analysed for the presence of intraplaque haemorrhage, lipid core, calcification, collagen, smooth muscle cells, and macrophages. Patients were stratified according to their diabetic status and year of inclusion. All patients had a follow up of three years in which cardiovascular adverse events were recorded.

RESULTS

A time dependent decrease was observed in intraplaque haemorrhage, plaque lipid core, and percentage of macrophages in IFE patients with diabetes. After multivariable correction for changes in risk factors over time, intraplaque haemorrhage (64.2% [2002-2005] vs. 39.6% [2012-2014], p = .01) became significantly less prevalent. Interestingly, the percentage of severely calcified plaques remained high over time. The number of secondary events decreased over time in patients without diabetes (HR 1.80, 95% CI 1.15-2.81 (p = .010) for 2002-2005 vs. 2012-2014), but remained high and unchanged in patients with diabetes.

CONCLUSION

In patients with diabetes undergoing IFE, a time dependent stabilisation of atherosclerotic plaque features was found in line with previous observations in patients with severe atherosclerosis. The presence of severely calcified lesions remained high and unchanged. The secondary event rate remained high in patients with diabetes in contrast to a significant decrease in patients without diabetes. These findings stress the need for improvement of care in IFE patients with diabetes.

Insulin Dependence Is Associated With Increased Risk of Complications After Upper Extremity Surgery in Diabetic Patients

Diabetes mellitus (DM) is associated with the development of carpal tunnel syndrome, Dupuytren disease, trigger digits, and limited joint mobility. Despite descriptions of poorer response to nonsurgical treatment, previous studies have not shown increased complication rates in diabetic patients after hand surgery. Few studies, however, differentiate between insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. The purpose of this study was to evaluate the impact of insulin dependence on the postoperative risk profile of diabetic patients after hand surgery using a national database.

MATERIALS AND METHODS

The data were obtained through the National Surgical Quality Improvement Program (NSQIP) database. Patients undergoing surgery from the distal humerus to the hand, between 2005 and 2015, were identified using 297 distinct Current Procedural Terminology codes. Thirty-day postoperative complications were collected and categorized into medical complications, surgical site complications, and readmission. Surgical complications, medical complications, and readmissions were compared between patients with NIDDM or IDDM to those without DM using multivariable logistic regression, adjusting for baseline patient and operative characteristics.

RESULTS

The study cohort included 52,727 patients. Patients with IDDM had a 5.7% overall complication rate compared with 2.3% and 1.5% in NIDDM and nondiabetic patients, respectively. After controlling for differences in patient and surgical characteristics, patients with IDDM had a statistically significant increased rate of any complication, surgical site complications, superficial surgical site infections, and readmission. There was no significant difference in complication rates between patients with NIDDM and nondiabetic patients.

CONCLUSIONS

Our data demonstrate a greater risk of complications following hand and upper extremity surgery for patients with IDDM, specifically surgical site infections. The NIDDM patients did not have an increased rate of complications relative to nondiabetic patients. These findings are important for patient risk stratification and may guide further investigation to decrease complication rates in IDDM patients after upper extremity surgery.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Predictive Parameters for Clinical Outcome in Patients with Critical Limb Ischemia Who Underwent Percutaneous Transluminal Angioplasty (PTA): A Systematic Review

Purpose

To identify possible risk factors in predicting clinical outcome in critical limb ischemia (CLI) patients undergoing percutaneous transluminal angioplasty (PTA).

Materials and Methods

PubMed and EMBASE were searched for studies analyzing CLI and clinical outcome after PTA from January 2006 to April 2017. Outcome measures were ulcer healing, amputation free survival (AFS)/limb salvage and overall survival. Data on predictive factors for ulcer healing, AFS/limb salvage and survival were extracted.

Results

Ten articles with a total of 2448 patients were included, all cohorts and based on prospective-designed databases. For ulcers, it seems that complete healing can be achieved in most of the patients within 1 year. No significant predictive factors were found. AFS/limb salvage: AFS rates for 1, 2 and 3 years ranged from 49.5 to 75.2%, 37 to 58% and 22 to 59%, respectively. Limb salvage rates for 1, 2 and 3 years ranged from 71 to 95%, 54 to 93.3% and 32 to 92.7%, respectively. All studies had different univariate and multivariate outcomes for predictive factors; however, age and diabetes were significant predictors in at least three studies. Survival: Survival rates for 1, 2 and 3 years ranged from 65.4 to 91.5%, 45.7 to 76% and 37.3 to 83.1%, respectively. Different predictive factors were found; however, age was found in 2 out of 5 studies reporting on predictive factors.

Conclusions

In several studies two factors, age and diabetes, were found as predictive factors for AFS/limb salvage and survival in patients with CLI undergoing PTA. Therefore, we believe that these factors should be taken into account in future research.

Level of Evidence

Level 2a.

Major Limb Outcomes Following Lower Extremity Endovascular Revascularization in Patients With and Without Diabetes Mellitus

PURPOSE

To determine whether diabetes mellitus has an independent impact on major limb outcomes at 1 year after endovascular treatment of lower extremity peripheral artery disease (PAD).

METHODS

The study involved 1906 consecutive patients (mean age 66 years; 1469 men) enrolled in the observational Excellence in Peripheral Artery Disease (XLPAD) registry ( ClinicalTrials.gov identifier NCT01904851) between January 2005 and October 2015 after undergoing index endovascular procedures in 2426 limbs for arterial occlusive disease. Patient outcomes included 12-month target limb amputation (above ankle) and target limb revascularization as well as all-cause death. Kaplan-Meier analysis and adjusted Cox proportional hazard models were used for time-to-event analysis of outcomes for the entire study sample as well as for the critical limb ischemia (CLI) and claudication subgroups. Results of the Cox regression models are reported as the hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Diabetics undergoing endovascular procedures had higher rates of comorbid conditions (p<0.001), CLI (p<0.001), heavily calcified lesions (p=0.002), multivessel disease (p=0.030), and fewer infrapopliteal runoff vessels (p<0.001). Regression analysis after adjusting for confounders revealed significantly higher target limb major amputation in diabetics compared with nondiabetics (HR 5.02, 95% CI 1.44 to 17.56, p=0.011). However, repeat revascularization rates were similar. When considering CLI and claudication subgroups, diabetes was associated with a nonsignificant increased risk of 12-month major amputation only for patients presenting with CLI (HR 3.48, 95% CI 0.97 to 12.51, p=0.056). Diabetes was also associated with an increased risk of 12-month all-cause mortality in the overall study sample (HR 4.64, 95% CI 2.01 to 10.70, p<0.001) and in the CLI subgroup (HR 14.15, 95% CI 3.16 to 63.32, p<0.001) but not in the claudication subgroup (HR 1.42, 95% CI 0.45 to 4.54, p=0.552).

CONCLUSION

Diabetes increases the risk of major amputation and all-cause death at 12 months following endovascular revascularization in patients with symptomatic PAD. These risks are especially heightened in patients presenting with CLI.

Think Before Chopping a Diabetic Foot: Insight to Vascular Intervention

Diabetes mellitus is a most commonly occurring chronic disease around the world, resulting in damage to multiple organs. One of the consequences of poorly controlled diabetes is vascular damage resulting in peripheral artery disease, leading to inadequate perfusion of the foot and eventually gangrene and amputation. Research over the past decade or so has provided us with the statistics that vascular intervention has better clinical outcomes including patient mortality, morbidity, quality of life, and patient satisfaction. This editorial advocates the importance of pursuing a vascular plan prior to a limb salvaging procedure. We highlight some important aspects of saving a diabetic foot and encourage the importance of giving a vascular trial.

Nitinol Self-Expanding Stents for the Superficial Femoral Artery

The superficial femoral artery is a complex artery subject to a unique set of biomechanical loading conditions in its course through the leg. Plain balloon angioplasty and balloon-expandable stents had unacceptably high rates of restenosis, necessitating target vessel revascularization. Nitinol alloy is well suited to provide the strength and flexibility needed of stents to withstand the external forces posed by the environment of the superficial femoral artery. Advances in stent technology with the addition of a slow-releasing antiproliferative agent and changes in scaffold design have shown promise in reducing the rates of stent fracture and in-stent restenosis.

Impact of Calcification on Clinical Outcomes After Endovascular Therapy for Superficial Femoral Artery Disease

Purpose: To investigate whether the severity of lesion calcification assessed by the novel peripheral artery calcification scoring system (PACSS) was associated with clinical outcomes after endovascular therapy (EVT) for superficial femoral artery (SFA) lesions. Methods: A retrospective analysis was conducted of 394 consecutive patients (mean age 72±8 years; 290 men) with intermittent claudication [223 (57%) with diabetes, 81 (21%) on hemodialysis] who underwent successful EVT for de novo SFA lesions [length 152.1±95.7 mm; 199 (50%) TransAtlantic Inter-Society Consensus II class C/D] between January 2010 and December 2013. The patients were retrospectively categorized using the PACSS classification (grades 0–4: no visible calcification of the target lesion, unilateral wall calcification <5 cm, unilateral calcification ≥5 cm, bilateral wall calcification <5 cm, and bilateral calcification ≥5 cm, respectively). The main outcome was primary patency, while the secondary outcome measures were mortality and major adverse limb events [MALE: any intervention (repeat EVT or surgical revision) or major (above ankle) amputation]. Cox proportional hazards analysis was used to explore whether the PACSS classification was an independent predictor of clinical outcomes. Results are presented as the hazard ratio (HR) and 95% confidence interval (CI). Results: The distribution of PACSS grades was 0 in 54%, grade 1 in 16%, grade 2 in 12%, grade 3 in 9%, and grade 4 in 9%. The 2-year primary patency rates in these grades, respectively, were 70.0%, 66.6%, 72.1%, 55.6%, and 36.3% (p<0.001). After multivariate analysis, PACSS grade 4 (HR 2.74, 95% CI 1.56 to 4.83, p<0.001), diabetes (HR 1.52, 95% CI 1.06 to 2.20, p=0.022), lesion length (HR 1.04, 95% CI 1.01 to 1.07, p=0.006), and vessel diameter (HR 0.80, 85% CI 0.65 to 0.98, p=0.038) were associated with loss of primary patency. PACSS grade 4 was also associated with MALE and mortality (p=0.048 and 0.011, respectively). Bare metal stent use (HR 0.47, 95% CI 0.30 to 0.73, p<0.001) was positively associated with primary patency. Conclusion: PACSS grade 4 calcification was independently associated with clinical outcomes after EVT for de novo SFA lesions.

Dorsomorphin homologue 1, a highly selective small-molecule bone morphogenetic protein inhibitor, suppresses medial artery calcification

BACKGROUND

Medial artery calcification develops in diabetes, chronic kidney disease, and as part of the aging process. It is associated with increased morbidity and mortality in vascular patients. Bone morphogenetic proteins (BMPs) have previously been implicated in the initiation and progression of vascular calcification. We thus evaluated whether dorsomorphin homologue 1 (DMH1), a highly selective BMP inhibitor, could attenuate vascular calcification in vitro and in an organ culture model of medial calcification.

METHODS

Confluent human aortic smooth muscle cells (SMCs) were cultured in calcification medium containing 3.0 mM inorganic phosphate (Pi) for 7 days with or without DMH1. Medial calcification was assessed using an aortic organ culture model. Calcification was visualized by alizarin red S staining, and calcium concentration was assessed by an o-cresolphthalein complexone calcium assay. Osteogenic cell and vascular SMC markers were determined by Western blot, quantitative reverse transcription polymerase chain reaction, and immunohistochemical staining.

RESULTS

DMH1 reduced Pi-induced calcium deposition in human SMCs. It also antagonized human recombinant BMP2-induced calcium accumulation. Western blot further revealed that DMH1 was able to block Pi-mediated upregulation of the osteoblast markers osterix and alkaline phosphatase and downregulation of the SMC markers smooth muscle myosin heavy chain and SM22α as well as p-Smad1/5/8, suggesting that DMH1 may regulate SMC osteogenic differentiation through the BMP/Smad1/5/8 signaling pathway. Finally, using an ex vivo aortic ring organ culture model, we observed that DMH1 reduces Pi-induced aortic medial calcification.

CONCLUSIONS

The selective BMP inhibitor DMH1 can inhibit calcium accumulation in vascular SMCs and arterial segments exposed to elevated phosphate levels. Such small molecules may have clinical utility in reducing medial artery calcification in our population of vascular patients.

Impact of Chronic Kidney Disease on Clinical Outcomes of Endovascular Treatment for Femoropopliteal Arterial Disease

PURPOSE

To evaluate effect of chronic kidney disease (CKD) on all-cause mortality, major adverse limb event (MALE), MALE and postoperative death (MALE + POD), and amputation after endovascular treatment of femoropopliteal disease.

MATERIALS AND METHODS

A retrospective review from January 2002 to October 2011 was performed of 440 patients who underwent endovascular treatment of symptomatic femoropopliteal disease for claudication (n = 251) or critical limb ischemia (CLI) (n = 267). CKD stage was divided based on Kidney Dialysis Outcomes Quality Initiative classification. Outcomes and factors associated with amputation, MALE, and MALE + POD were determined.

RESULTS

Patients with diabetes (hazard ratio [HR] = 2.2; 95% confidence interval [CI], 1.3-3.6; P = .002) and runoff score of 0 or 1 (HR = 2.0; 95% CI, 1.2-3.4; P = .01) relative to runoff score of 3 were at increased risk of amputation. Patients with baseline glomerular filtration rate < 45 mL/min/1.73 m(2) had a 17% increase in amputation for every 5-point decrease < 45 mL/min/1.73 m(2) (95% CI, 1.09-1.26; P < .001). Increase of 10 years in age (HR = 1.9; 95% CI, 1.5-2.3; P < .001), TransAtlantic Inter-Society Consensus class of C/D relative to A/B (HR = 1.6; 95% CI, 1.1-2.2; P = .01), and CLI (HR = 2.4; 95% CI, 0.5-0.9; P < .001) were associated with increased mortality. Female sex was associated with decreased risk of mortality (HR = 0.7; 95% CI, 0.5-0.9; P = .01).

CONCLUSIONS

Worsening CKD is associated with higher amputation rates, all-cause mortality, and MALE + POD in patients undergoing endovascular treatment of femoropopliteal disease.

Association of cardiovascular and biochemical risk factors with tibial artery calcification

The cardiovascular risk factors that contribute to coronary calcification have been extensively studied while those related to tibial artery calcium are less well defined. We sought to determine the associations between cardiovascular risk factors and tibial artery calcification in a cohort of patients with and without significant peripheral atherosclerosis. A total of 222 patients without end-stage renal disease were identified in a prospectively maintained database containing tibial artery calcification (TAC) scores, and demographic, cardiovascular, and biochemical risk factor information. Patients with prevalent tibial artery calcification were more likely to be older, male, and have a history positive for hypertension, hyperlipidemia, diabetes, and tobacco use. Patients with an abnormal ankle-brachial index (ABI) or symptoms of peripheral artery disease (PAD) were also more likely to have higher calcium values. In analyses using multivariable logistic regression, age, gender, diabetes, and tobacco use maintained their association with prevalent tibial calcification while hypertension, hyperlipidemia and body mass index did not. These associations remained when PAD was added to the model. After adjusting for relevant cardiovascular risk factors, we found that only abnormal ABI, current PAD symptoms, and lower serum calcium values were associated with the presence of tibial artery calcification. In conclusion, in patients without end-stage renal disease, tibial artery calcification has risk factors that are similar but not identical to those for coronary artery calcification and peripheral atherosclerosis.

Retrospective review of superficial femoral artery stenting in diabetic patients: thiazolidinedione use may decrease reinterventions

Background

Diabetics are known to have inferior outcomes following peripheral vascular interventions. Thiazolidinediones are oral diabetic agents which improve outcomes following coronary bare metal stenting. No studies have been performed evaluating thiazolidinedione use and outcomes following lower extremity endovascular interventions. We hypothesize that diabetic patients taking thiazolidinediones at the time of primary superficial femoral artery (SFA) stenting have fewer reinterventions.

Methods

A retrospective review was performed to identify diabetic patients undergoing primary SFA stenting. The unit of analysis was the extremity. The primary outcome was freedom from target lesion revascularization stratified by thiazolidinedione use, evaluated by Kaplan Meier curves and a log rank test. A Cox proportional hazards model was constructed to determine variables associated with freedom from target lesion revascularization.

Results

SFA stents were placed in 138 extremities in 128 diabetic patients between August 1, 2001 and July 15, 2012. Twenty-four patients were taking thiazolidinediones at the time of SFA stenting. All patients taking thiazolidinediones had TASC A or B lesions. Twenty-seven extremities in the non-thiazolidinedione group had TASC C or D lesions and were excluded to control for disease severity. Freedom from target lesion revascularization was significantly higher in diabetics taking thiazolidinediones at 2 years, 88.5% vs. 59.4%, P = 0.02, SE < 10%. Cox modeling identified a protective trend for thiazolidinedione use (thiazolidinedione use HR 0.33, 95% CI 0.09-1.13), whereas critical limb ischemia and insulin use were associated with trends for worse freedom from target lesion revascularization.

Conclusions

This pilot, translation study demonstrates that diabetic patients taking thiazolidinediones at the time of primary SFA stenting have decreased reintervention rates at 2 years. These results may be explained by higher adiponectin levels or other anti-inflammatory effects in patients taking thiazolidinedione. National and regional quality improvement registries should consider collecting information regarding specific diabetic regimens and use of PPAR agonists such as cilostazol and fibrates.

Management of critical lower limb ischemia in endovascular era: experience from 511 patients

This study aims at the assessment of the achievability of the endovascular treatment of patients with critical limb ischemia (CLI) and the role of bypass in such patient. This is a prospective study conducted on patients with chronic atherosclerotic critical lower limb ischemia presenting to us over a period of 3 years. Patients presenting with nonsalvageable limbs requiring primary major amputation and nonatherosclerotic causes of CLI were excluded. Endovascular treatment was the first choice modality of treatment in revascularization of all patients. Open surgery was offered selectively for patient whom endovascular failed or complicated and for long TransAtlantic Inter-Society Consensus (TASC) II lesions in fit patients. This study included 511 cases of CLI, and the mean age was 64.5 years. Patients with Rutherford IV, V, and VI were 19.25, 60.5, and 19.25%, respectively. The TASC II aortoiliac lesions were as follows: A, B, C, and D in 33.7, 12,15.7, and 38.6%, respectively, and infrainguinal lesions were A, B, C, and D in 3.7, 19, 35.4, and 68.3%, respectively. A total of 78.3% of patients were treated by endovascular totally, while 16% were treated by surgery from the start, 3.7% of endovascular cases were converted to open surgery after failure of endovascular treatment, and 2% was offered hybrid treatment. Crossing of lesions by subintimal and intraluminal was 12.5 and 87.5%, respectively. Technical success in endovascular was 94%; however, we could successfully revascularize 96.8% of all CLI presented in this study by either surgery or endovascular. On 24 months follow-up, primary patency, secondary patency, and limb salvage by percutaneous transluminal angioplasty are 77.8, 84.7, and 90.7%, respectively. Revascularization by endovascular achieves high technical success and limb salvage in CLI, hence should be considered as preferred choice of treatment. However, both endovascular and surgery should not be counteracting each other and using both can revascularize 96.6% of CLI.

Effect of metabolic syndrome on the response to arterial injury

BACKGROUND

Metabolic syndrome is now an epidemic in the United States population. Intimal hyperplasia remains the principal lesion in the development of restenosis after vessel wall injury. The aim of this study is to characterize the changes induced in wall morphology in the developing intimal hyperplasia within a murine model in the presence of diabetes (type 1) and metabolic syndrome.

METHODS

Control (wild type B6), Non Obese Diabetic, and metabolic syndrome (RCS-10) mice were used. The murine femoral wire injury model was used in which a micro wire is passed through a branch of the femoral and used to denude the common femoral and iliac arteries. Specimens were perfusion fixed and sections were stained with hematoxylin and eosin and Movat stains such that dimensional and compositional morphometry could be performed using an ImagePro system. Additional stains for proliferation and apoptosis were used.

RESULTS

In control mice, the injured femoral arteries develop intimal hyperplasia, which is maximal at 28 d and remains stable to day 56. Sham-operated vessels do not produce such a response. In diabetic mice, the intimal response increased 5-fold with a 2-fold increase in proteoglycan deposition, whereas in the metabolic syndrome mice there was a 6-fold increase in the intimal response and a similar increase in proteoglycan deposition. Collagen deposition was different with a 22-fold increase over control in collagen deposition in diabetes and a 100-fold increase over control in collagen deposition in metabolic syndrome as compared with the control injury mice. Maximal vascular smooth muscle cell (VSMC) proliferation was decreased in both diabetes and metabolic syndrome compared with controls, whereas early cell apoptosis in both diabetes and metabolic syndrome was sustained over a longer period of time compared with wild-type mice.

CONCLUSIONS

These data demonstrate that development of intimal hyperplasia is markedly different in diabetes and metabolic syndrome compared with controls, with an increase in collagen deposition, a reduction in VSMC proliferation, and an increase in early VSMC apoptosis. These findings suggest that preventative strategies against restenosis must be tailored for the diabetic and metabolic syndrome patients.

Peripheral arterial disease and bypass surgery in the diabetic lower limb

PAD is very common in people with diabetes and is one of the strongest predictors of developing nonhealing foot ulcers and suffering amputation. There is strong evidence to show that early detection of PAD and revascularization will reduce amputations. Despite this, many patients have no vascular assessment even when they present with a foot ulcer or before amputation. Even when identified, patients are referred late, which worsens their outcome. Currently there is no evidence to support surgical revascularization over endovascular treatments, but in reality the techniques are complementary and the choice of revascularization procedure should be determined by an experienced multidisciplinary vascular team. Surgical revascularization can achieve good results but careful patient selection, operative planning, and the use of autologous vein are necessary. What is clearly apparent is that at present not enough patients are being offered revascularization to prevent amputation.

Pilot trial of cryoplasty or conventional balloon post-dilation of nitinol stents for revascularization of peripheral arterial segments: the COBRA trial

OBJECTIVES

The purpose of this study is to compare post-dilation strategies of nitinol self-expanding stents implanted in the superficial femoral artery of diabetic patients with peripheral arterial disease.

BACKGROUND

Endovascular treatment of superficial femoral artery disease with nitinol self-expanding stents is associated with high rates of in-stent restenosis in patients with diabetes mellitus.

METHODS

We conducted a prospective, multicenter, randomized, controlled clinical trial of diabetic patients to investigate whether post-dilation of superficial femoral artery nitinol self-expanding stents using a cryoplasty balloon reduces restenosis compared to a conventional balloon. Inclusion criteria included diabetes mellitus, symptomatic peripheral arterial disease, and superficial femoral artery lesions requiring implantation of stents>5 mm in diameter and >60 mm in length. Primary endpoint was binary restenosis at 12 months, defined as ≥2.5-fold increase in peak systolic velocity by duplex ultrasonography.

RESULTS

Seventy-four patients, with 90 stented superficial femoral artery lesions, were randomly assigned to post-dilation using cryoplasty (n=45 lesions) or conventional balloons (n=45 lesions). Mean lesion length was 148±98 mm, mean stented length was 190±116 mm, mean stent diameter was 6.1±0.4 mm, and 50% of the lesions were total occlusions. Post-dilation balloon diameters were 5.23±0.51 mm versus 5.51±0.72 mm in the cryoplasty and conventional balloon angioplasty groups, respectively (p=0.02). At 12 months, binary restenosis was significantly lower in the cryoplasty group (29.3% vs. 55.8%, p=0.01; odds ratio: 0.36, 95% confidence interval: 0.15 to 0.89).

CONCLUSIONS

Among diabetic patients undergoing implantation of nitinol self-expanding stents in the superficial femoral artery, post-dilation with cryoplasty balloon reduced binary restenosis compared to conventional balloon angioplasty. (Study Comparing Two Methods of Expanding Stents Placed in Legs of Diabetics With Peripheral Vascular Disease [COBRA]; NCT00827853).

Neo-intimal hyperplasia, diabetes and endovascular injury

Diabetes is a significant major risk factor for peripheral arterial disease (PAD) and critical limb ischaemia (CLI), the latter which is also the most common cause of amputation in these patients. Revascularisation of the lower extremities of such patients is imperative for limb salvage and has become First-line therapy. However, the incidence of restenosis following endovascular stenting is very high and is largely due to neo-intimal hyperplasia (NIH), the regulation of which is for the greater part not understood. This article therefore reviews our understanding on the regulation of NIH following stent-induced vascular injury, and highlights the importance of future studies to investigate whether the profile of vascular progenitor cell differentiation, neo-intimal growth factors and lumen diameters predict the severity of post-stent NIH in the peripheral arteries. Results from future studies will (1) better our understanding of the regulation of NIH in general, (2) determine whether combinations of any of the vascular factors discussed are predictive of the extent of NIH postoperatively, and (3) potentially facilitate future therapeutic targets and/or change preventive strategies.

Efficacy of endoluminal interventional therapy in diabetic peripheral arterial occlusive disease: a retrospective trial

Background

The purpose of this study was to assess the efficacy of interventional therapy for peripheral arterial occlusive disease and the difference between diabetic patients and non-diabetic patients.

Methods

139 consecutive patients between September 2006 and September 2010 who underwent percutaneous lower extremity revascularization for arterial lesions were divided into diabetes group (n = 62) and non-diabetes group (n = 77). Before intervention, rest ankle brachial indexes and three dimensional computed tomography angiography from abdominal aorta to tiptoe were performed. The interventional treatments included angioplasty with or without stenting. The clinical outcomes included rest ankle-brachial indexes, primary patency rates, secondary patency rates and limb-salvage rates for 6-month, 12-month, 24-month and 36-month after treatment. The primary and secondary patency rates of all interventions and the limb-salvage rates of the patients are illustrated by Kaplan-Meier curves and compared by log-rank analysis.

Results

The interventional operation success rates were 98.4% (61/62) in diabetes group and 100% (77/77) in non-diabetes group. The re-interventional operation success rates were 85.7% (18/21) in diabetes group and 76.9% (20/26) in non-diabetes group. The mean value of ankle brachial indexes was significantly increased after intervention (0.397 ± 0.125 versus 0.779 ± 0.137, t = -25.780, P < 0.001) in diabetes group and (0.406 ± 0.101 versus 0.786 ± 0.121, t = -37.221, P < 0.001) in non-diabetes group. Perioperative 30-day mortality was 0%. Major complications included groin hematoma in 7.2%, and pseudoaneurysm formation 2.2%. In diabetes group, 6, 12, 24, and 36-month primary patency rates were 88.7% ± 4.0%, 62.3% ± 6.6%, 55.3% ± 7.0%, and 46.5% ± 7.5%; secondary patency rates were 93.5% ± 3.1%, 82.3% ± 5.1%, 70.8% ± 6.5%, and 65.7% ± 7%; limb-salvage rates were 95.2% ± 2.7%, 87.7% ± 4.4%, 85.5% ± 4.8%, and 81.9% ± 5.8%. In non-diabetes group, 6, 12, 24, and 36-month primary patency rates were 90.9% ± 3.3%, 71.8% ± 5.4%, 71.8% ± 5.4%, and 60.9% ± 6.2%; secondary patency rates were 96.1% ± 2.2%, 91.6% ± 3.3%, 82.7% ± 4.8%, and 71.8% ± 6.2%; limb-salvage rates were 97.4% ± 1.8%, 94.4% ± 2.7%, 90.6% ± 3.7%, and 83.1% ± 5.4%. The differences between two groups were not significant (P > 0.05).

Conclusion

With a low risk of morbidity and mortality, the percutaneous revascularization accepted by patients does not affect ultimate necessary surgical revascularization and consequently should be considered as the preferred therapy for chronic lower extremity ischemia. The efficacy and prognosis of interventional therapy in diabetic patients is similar that in non-diabetic patients.

Clinical outcomes after endovascular treatment of superficial femoral disease in patients with disabling claudication and critical limb ischemia: midterm analysis

We present the midterm clinical outcomes and predictors of balloon angioplasty and stent placement in atherosclerotic femoropopliteal (FP) arterial disease. Between January 2002 and August 2006, 155 patients (men = 56%; 71.4 ± 10.5 years) underwent 171 FP angioplasty or stent for claudication (n = 82, 54%) or critical limb ischemia ([CLI] n = 70, 46%). Follow-up was obtained through September 30, 2009. The average follow-up was 3.25 ± 1.73 years. In claudicants versus CLI, the 12-month patency for TransAtlantic InterSociety Consensus II (TASC II) classification (TASC A/B) was 93% versus 80%, respectively, and TASC C/D 83% versus 80%. At 3 years, TASC A/B was 82% versus 80%, respectively, and TASC C/D was 56% versus 80%, respectively. The predictor of clinical failure in claudicants was chronic renal insufficiency (CRI) and in CLI, the predictor of amputation was hyperlipidemia.

Long-term results of open and endovascular revascularization of superficial femoral artery occlusive disease

BACKGROUND

First-line treatment for patients with superficial femoral arterial (SFA) occlusive disease has yet to be determined. This study compared long-term outcomes between primary SFA stent placement and primary femoral-popliteal bypass. Periprocedural patient factors were examined to determine their effect on these results.

METHODS

All femoral-popliteal bypasses and SFA interventions performed in consecutive patients with symptoms Rutherford 3 to 6 between 2001 and 2008 were reviewed. Time-dependent outcomes were analyzed using the Kaplan-Meier method and log-rank test. Cox proportional hazards were performed to determine predictors of graft patency. Multivariate analysis was completed to identify patient covariates most often associated with the primary therapy.

RESULTS

A total of 152 limbs in 141 patients (66% male; mean age, 66 ± 22 years) underwent femoral-popliteal bypass, and 233 limbs in 204 patients (49% male; mean age, 70 ± 11 years) underwent SFA interventions. Four-year primary, primary-assisted, and secondary patency rates were 69%, 78%, and 83%, respectively, for bypass patients and 66%, 91%, and 95%, respectively, for SFA interventions. Six-year limb salvage was 80% for bypass vs 92% for stenting (P = .04). Critical limb ischemia (CLI) and renal insufficiency were predictors of bypass failure. Claudication was a predictor of success for SFA stenting. Three-year limb salvage rates for CLI patients undergoing surgery and SFA stenting were 83%. Amputation-free survival at 3 years for CLI patients was 55% for bypass and 59% for SFA interventions. Multivariate predictors (odds ratios and 95% confidence intervals) of covariates most frequently associated with first-line SFA stenting were TransAtlantic Inter-Society Consensus II A and B lesions (5.9 [3.4-9.1], P < .001), age >70 years (2.1 [1.4-3.1], P < .001), and claudication (1.7 [1.1-2.7], P = .01). Regarding bypass as first-line therapy, claudicant patients were more likely to have nondiabetic status (5.6 [3.3-9.4], P < .001), creatinine <1.8 mg/dL (4.6 [1.5-14.9], P = .01), age <70 years (2.7 [CI, 1.6-8.3], P < .001), and presence of an above-knee popliteal artery target vessel (1.9 [CI, 1.1-3.4] P = .02).

CONCLUSION

Indication, patient-specific covariates, and anatomic lesion classification have significant association when determining surgeon selection of SFA stenting or femoral-popliteal bypass as first-line therapy. Patients with SFA disease can have comparable long-term results when treatment options are well matched to patient-specific and anatomic characteristics.

Current assessment of endovascular therapy for infrainguinal arterial occlusive disease in patients with diabetes

Endovascular therapy has increasingly become the initial clinical option for the treatment of lower-extremity peripheral arterial occlusive disease not only for patients with claudication but also for those with critical limb ischemia. Despite this major clinical practice paradigm shift, the outcomes of endovascular therapy for peripheral arterial disease are difficult to evaluate and compare with established surgical benchmarks because of the lack of prospective randomized trials, incomplete characterization of indications for intervention, mixing of arterial segments and extent of disease treated, the multiplicity of endovascular therapy techniques used, the exclusion of early treatment failures, crossover to open bypass during follow-up, and the frequent lack of intermediate and long-term patency and limb salvage rates in life-table format. These data limitations are especially problematic when one tries to assess the outcomes of endovascular therapy in patients with diabetes. The purpose of the present article is to succinctly review and objectively analyze available data regarding the results of endovascular therapy in patients with diabetes.

Predictors of failure and success of tibial interventions for critical limb ischemia

OBJECTIVE

The efficacy of tibial artery endovascular intervention (TAEI) for critical limb ischemia (CLI) and particularly for wound healing is not fully defined. The purpose of this study is to determine predictors of failure and success for TAEI in the setting of CLI.

METHODS

All TAEI for tissue loss or rest pain (Rutherford classes 4, 5, and 6) from 2004 to 2008 were retrospectively reviewed. Clinical outcomes and patency rates were analyzed by multivariable Cox proportional hazards regression and life table analysis.

RESULTS

One hundred twenty-three limbs in 111 patients (62% male, mean age 74) were treated. Sixty-seven percent of patients were diabetics, 55% had renal insufficiency, and 21% required hemodialysis. One hundred two limbs (83%) exhibited tissue loss; all others had ischemic rest pain. All patients underwent tibial angioplasty (PTA). Tibial excimer laser atherectomy was performed in 14% of the patients. Interventions were performed on multiple tibial vessels in 20% of limbs. Isolated tibial procedures were performed on 50 limbs (41%), while 73 patients had concurrent ipsilateral superficial femoral artery or popliteal interventions. The mean distal popliteal and tibial runoff score improved from 11.8 ± 3.6 to 6.7 ± 1.6 (P < .001), and the mean ankle-brachial index increased from 0.61 ± 0.26 to 0.85 ± 0.22 (P < .001). Surgical bypass was required in seven patients (6%). The mean follow up was 6.8 ± 6.6 months, while the 1-year primary, primary-assisted, and secondary patency rates were 33%, 50%, and 56% respectively. Limb salvage rate at 1 year was 75%. Factors found to be associated with impaired limb salvage included renal insufficiency (hazard ratio [HR] = 5.7; P = .03) and the need for pedal intervention (HR = 13.75; P = .04). TAEI in an isolated peroneal artery (odds ratio = 7.80; P = .01) was associated with impaired wound healing, whereas multilevel intervention (HR = 2.1; P = .009) and tibial laser atherectomy (HR = 3.1; P = .01) were predictors of wound healing. In patients with tissue loss, 41% achieved complete closure (mean time to healing, 10.7 ± 7.4 months), and 39% exhibited partial wound healing (mean follow up, 4.4 ± 4.8 months) at last follow up. Diabetes, smoking, statin therapy, and revascularization of > 1 tibial vessel had no impact on limb salvage or wound healing. Re-intervention rate was 50% at 1 year.

CONCLUSIONS

TAEI is an effective treatment for CLI with acceptable limb salvage and wound healing rates, but requires a high rate of reintervention. Patients with renal failure, pedal disease, or isolated peroneal runoff have poor outcomes with TAEI and should be considered for surgical bypass.

Cryoplasty versus conventional balloon angioplasty of the femoropopliteal artery in diabetic patients: long-term results from a prospective randomized single-center controlled trial

The purpose of this study was to investigate the immediate and long-term results of cryoplasty versus conventional balloon angioplasty in the femoropopliteal artery of diabetic patients. Fifty diabetic patients (41 men, mean age 68 years) were randomized to cryoplasty (group CRYO; 24 patients with 31 lesions) or conventional balloon angioplasty (group COBA; 26 patients with 34 lesions) of the femoropopliteal artery. Technical success was defined as <30% residual stenosis without any adjunctive stenting. Primary end points included technical success, primary patency, binary in-lesion restenosis (>50%), and freedom from target lesion recanalization. Cox proportional hazards regression analysis was performed to adjust for confounding factors of heterogeneity. In total, 61.3% (19 of 31) in group CRYO and 52.9% (18 of 34) in group COBA were de novo lesions. More than 70% of the lesions were Transatlantic Inter-Society Consensus (TASC) B and C in both groups, and 41.4% of the patients in group CRYO and 38.7% in group COBA suffered from critical limb ischemia. Immediate technical success rate was 58.0% in group CRYO versus 64.0% in group COBA (p = 0.29). According to 3-year Kaplan-Meier estimates, there were no significant differences with regard to patient survival (86.8% in group CRYO vs. 87.0% in group COBA, p = 0.54) and limb salvage (95.8 vs. 92.1% in groups CRYO and COBA, respectively, p = 0.60). There was a nonsignificant trend of increased binary restenosis in group CRYO (hazard ratio [HR] 1.3; 95% CI 0.6-2.6, p = 0.45). Primary patency was significantly lower in group CRYO compared with group COBA (HR 2.2; 95% CI 1.1-4.3, p = 0.02). Significantly more repeat intervention events because of recurrent symptoms were required in group CRYO (HR 2.5; 95% CI 1.2-5.3, p = 0.01). Cryoplasty was associated with lower primary patency and more clinically driven repeat procedures after long-term follow-up compared with conventional balloon angioplasty.

Insulin enhances the effect of nitric oxide at inhibiting neointimal hyperplasia in a rat model of type 1 diabetes

Diabetes confers greater restenosis from neointimal hyperplasia following vascular interventions. While localized administration of nitric oxide (NO) is known to inhibit neointimal hyperplasia, the effect of NO in type 1 diabetes is unknown. Thus the aim of this study was to determine the efficacy of NO following arterial injury, with and without exogenous insulin administration. Vascular smooth muscle cells (VSMC) from lean Zucker (LZ) rats were exposed to the NO donor, DETA/NO, following treatment with different glucose and/or insulin concentrations. DETA/NO inhibited VSMC proliferation in a concentration-dependent manner to a greater extent in VSMC exposed to normal-glucose vs. high-glucose environments, and even more effectively in normal-glucose/high-insulin and high-glucose/high-insulin environments. G(0)/G(1) cell cycle arrest and cell death were not responsible for the enhanced efficacy of NO in these environments. Next, type 1 diabetes was induced in LZ rats with streptozotocin. The rat carotid artery injury model was performed. Type 1 diabetic rats experienced no significant reduction in neointimal hyperplasia following arterial injury and treatment with the NO donor PROLI/NO. However, daily administration of insulin to type 1 diabetic rats restored the efficacy of NO at inhibiting neointimal hyperplasia (60% reduction, P < 0.05). In conclusion, these data demonstrate that NO is ineffective at inhibiting neointimal hyperplasia in an uncontrolled rat model of type 1 diabetes; however, insulin administration restores the efficacy of NO at inhibiting neointimal hyperplasia. Thus insulin may play a role in regulating the downstream beneficial effects of NO in the vasculature.

Long-term outcomes of diabetic patients undergoing endovascular infrainguinal interventions

OBJECTIVE

Diabetes mellitus (DM) has traditionally predicted poor outcomes after lower extremity revascularization for peripheral vascular disease (PVD). This study assessed the influence of DM on long-term outcomes of percutaneous transluminal angioplasty, with or without stenting (PTA/stent), in patients with PVD.

METHODS

From January 2002 to December 2007, 920 patients underwent 1075 PTA/stent procedures. Patients were stratified into DM and non-DM cohorts. Study end points included primary patency (PP), assisted patency (AP), limb salvage, and survival and were evaluated using Kaplan-Meier and Cox regression analyses.

RESULTS

There were 533 DM and 542 non-DM limbs. Median follow-up was 34 months. Overall, the 5-year actuarial PP was 42% +/- 2.4%, AP was 81% +/- 2.0%, limb salvage was 89% +/- 1.6%, and survival was 60% +/- 2.4%. On univariate analysis, DM vs non-DM was associated with inferior 5-year PP (37% +/- 3.4% vs 46% +/- 3.3%; P = .009), limb salvage (84% +/- 2.6% vs 93% +/- 1.8%, P < .0001), and survival (52% +/- 3.5% vs 68% +/- 3.1%, P = .0001). AP did not differ between DM and non-DM patients (P = .18). In the entire cohort, DM (hazard ratio [HR], 1.25; 95% confidence interval [CI], 1.01-1.54; P = .04), single-vessel peroneal runoff (HR, 1.54; 95% CI, 1.16-2.08; P = .003), and dialysis (HR, 1.59; 95% CI, 1.10-2.33; P = .02) were associated with decreased PP on multivariate analysis. The only variables on multivariate analysis to predict limb loss and death were critical limb ischemia (HR, 9.09; 95% CI, 4.17-20.00; P < . 0001; HR, 2.99; 95% CI, 2.01-4.44; P < .0001, respectively) and dialysis (HR, 2.94; 95% CI, 1.39-5.00; P = .003; HR, 4.24; 95% CI 2.80-6.45; P < .0001, respectively).

CONCLUSIONS

DM is an independent predictor of decreased long-term primary patency after PTA/stent. Although acceptable assisted patency rates can be achieved with close surveillance and reintervention, long-term limb salvage remains inferior in diabetic patients compared with non-diabetic patients due to a more severe clinical presentation and poor runoff.