Risk factors, medical therapies and perioperative events in limb salvage surgery: observations from the PREVENT III multicenter trial

Exploring Prognostic Implications of Race and Ethnicity in Patients With Peripheral Arterial Disease

INTRODUCTION

Significant health inequalities in major adverse limb events exist. Ethnically minoritized groups are more prone to have a major adverse event following peripheral vascular interventions. This systematic review and meta-analysis aimed to describe the postoperative implications of racial and ethnic status on clinical outcomes following vascular interventions for claudication and chronic limb-threatening ischemia.

METHODS

Searches were conducted across seven databases from inception to June 2021 and were updated in October 2022 to identify studies reporting claudication or chronic limb-threatening ischemia in patients who underwent open, endovascular, or hybrid procedures. Studies with documented racial and ethnic status and associated clinical outcomes were selected. Extracted data included demographic and clinical characteristics, vascular interventions, and measured outcomes associated with race or ethnicity. Meta-analyses were performed using random-effect models to report pooled odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Seventeen studies evaluating the impact of Black versus White patients undergoing amputation as a primary intervention were combined in a meta-analysis, revealing that Black patients had a higher incidence of amputations as a primary intervention than White patients (OR: 1.91, 95% CI: 1.61-2.27). Another meta-analysis demonstrated that Black patients had significantly higher rates of amputation after revascularization (OR: 1.56, 95% CI: 1.28-1.89). Furthermore, multiple trends were demonstrated in the secondary outcomes evaluated.

CONCLUSIONS

Our findings suggest that Black patients undergo primary major amputation at a significantly higher rate than White patients, with similar trends seen among Hispanic and First Nations patients. Black patients are also significantly more likely to be subjected to amputation following attempts at revascularization when compared to White patients.

Rheocarna® therapy after distal bypass surgery

Objectives: Rheocarna® therapy has recently been reported to improve peripherally measured blood flow as an adjuvant treatment after revascularization in patients with chronic limb-threatening ischemia. We investigated whether skin perfusion pressure and continuous walking distance were improved by performing Rheocarna® therapy after distal bypass surgery. Methods: This study included 10 patients who underwent Rheocarna® therapy after distal bypass surgery between June 2022 and March 2023. Rheocarna® therapy was performed five times after distal bypass surgery, and the skin perfusion pressure and continuous walking distance after distal bypass surgery were compared with those after Rheocarna® therapy. Results: The average age was 74.7 years, and nine patients (90%) were male. All patients were undergoing dialysis, with an average of 14.5 years of dialysis history. There were six patients (60%) with diabetes mellitus and five (50%) with hyperlipidemia. The ankle-brachial index was 0.62 ± 0.36 before distal bypass surgery and 0.936 ± 0.16 after Rheocarna® therapy, indicating a significant increase (p = 0.0117). Skin perfusion pressure dorsalis pedis was 71.5 ± 27.0 mmHg after Rheocarna® therapy, showing a marked increase from the preoperative value (p = 0.0020). Skin perfusion pressure planta pedis was 65.0 ± 26.3 mmHg after Rheocarna® therapy, which was a significant increase from the preoperative value (p = 0.0293). The continuous walking distance was 78.5 ± 102.7 m after the Rheocarna® therapy, which was a significant increase from the preoperative value (p = 0.0039). Conclusion: The skin perfusion pressure and continuous walking distance were significantly improved by Rheocarna® therapy after distal bypass surgery.

Bias in Care: Impact of Ethnicity on Time to Emergent Surgery Varies Between Subspecialties

INTRODUCTION

Disparity in access to emergency care among minority groups continues to exist despite growing awareness of the effect of implicit bias on public health. In this study, we evaluated ethnicity-based differences in time between admission and surgery for patients undergoing emergent procedures at hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program.

METHODS

We conducted a retrospective review of 249,296 National Surgical Quality Improvement Program cases from 2006 to 2018 involving general, orthopaedic, and vascular surgeries. Analysis of variance was used to compare "time to operating room" (OR) between ethnic groups.

RESULTS

Notable differences in time to OR were noted among general and vascular surgeries but not orthopaedic surgery. Post hoc comparison identified notable variation in general surgery between White and Black/African Americans. In vascular surgery, notable variations were identified between White and Black/African Americans and White and Native Hawaiian/Pacific Islanders.

DISCUSSION

These findings suggest that certain surgical subspecialties continue to exhibit disparities in care that may manifest as surgical delay, most notably between White and Black/African Americans. Interestingly, variation in time to OR for patients treated by orthopaedic surgery was not notable. Overall, these results highlight the need for additional research into the role of implicit bias in emergent surgical care in the United States.

Lower extremity symptoms and ankle-brachial index screening as predictors of cardiovascular outcomes in Black adults

BACKGROUND

The prevalence of peripheral artery disease (PAD) and leg symptoms are higher in Black than White adults. We studied the effects of self-reported lower extremity symptoms and ankle-brachial indices (ABI) groups on outcomes.

METHODS

Black participants in the Jackson Heart Study with baseline ABI and PAD symptom assessments (exertional leg pain by the San Diego Claudication questionnaire) were included. Abnormal ABI was < 0.90 or > 1.40. Participants were divided into (1) normal ABI, asymptomatic, (2) normal ABI, symptomatic, (3) abnormal ABI, asymptomatic, and (4) abnormal ABI, symptomatic to examine their associations with MACE (stroke, myocardial infarction, fatal coronary heart disease) and all-cause mortality, using Kaplan-Meier survival curves and stepwise Cox proportional hazard models adjusting for Framingham risk factors.

RESULTS

Of 4586 participants, mean age was 54.6 ± 12.6 years, with 63% women. Compared with participants with normal ABI who were asymptomatic, participants with abnormal ABI and leg symptoms had highest risk of MACE (adjusted HR 2.28; 95% CI 1.62, 3.22) and mortality (aHR 1.82; 95% CI 1.32, 2.56). Participants with abnormal ABI without leg symptoms had higher risk for MACE (aHR 1.49; 95% CI 1.06, 2.11) and mortality (aHR 1.44; 95% CI 1.12, 1.99). Participants with normal ABI and no leg symptoms did not have higher risks.

CONCLUSION

Among Black adults, the highest risk for adverse outcomes were in symptomatic participants with abnormal ABIs, followed by asymptomatic participants with abnormal ABIs. These findings underscore the need for further studies to screen for PAD and develop preventative approaches in Black adults with asymptomatic disease.

Topical and intravenous administration of human umbilical cord mesenchymal stem cells in patients with diabetic foot ulcer and peripheral arterial disease: a phase I pilot study with a 3-year follow-up

Background

Diabetic foot ulcer (DFU) is a serious chronic complication of diabetes mellitus that contributes to 85% of nontraumatic lower extremity amputations in diabetic patients. Preliminary clinical benefits have been shown in treatments based on mesenchymal stem cells for patients with DFU or peripheral arterial disease (PAD). However, the long-term safety and benefits are unclear for patients with both DFU and PAD who are not amenable to surgical revascularization.

Methods

In this phase I pilot study, 14 patients with PAD and incurable DFU were enrolled to assess the safety and efficacy of human umbilical cord mesenchymal stem cell (hUC-MSC) administration based on conservative treatments. All patients received topical and intravenous administrations of hUC-MSCs at a dosage of 2 × 10⁵ cells/kg with an upper limit of 1 × 10⁷ cells for each dose. The adverse events during treatment and follow-up were documented for safety assessments. The therapeutic efficacy was assessed by ulcer healing status, recurrence rate, and 3-year amputation-free rate in the follow-up phase.

Results

The safety profiles were favorable. Only 2 cases of transient fever were observed within 3 days after transfusion and considered possibly related to hUC-MSC administration intravenously. Ulcer disclosure was achieved for more than 95% of the lesion area for all patients within 1.5 months after treatment. The symptoms of chronic limb ischaemia were alleviated along with a decrease in Wagner scores, Rutherford grades, and visual analogue scale scores. No direct evidence was observed to indicate the alleviation of the obstruction in the main vessels of target limbs based on computed tomography angiography. The duration of rehospitalization for DFU was 2.0 ± 0.6 years. All of the patients survived without amputation due to the recurrence of DFU within 3 years after treatments.

Conclusions

Based on the current pilot study, the preliminary clinical benefits of hUC-MSCs on DFU healing were shown, including good tolerance, a shortened healing time to 1.5 months and a favorable 3-year amputation-free survival rate. The clinical evidence in the current study suggested a further phase I/II study with a larger patient population and a more rigorous design to explore the efficacy and mechanism of hUC-MSCs on DFU healing.

Trial registration: The current study was registered retrospectively on 22 Jan 2022 with the Chinese Clinical Trial Registry (ChiCTR2200055885), http://www.chictr.org.cn/showproj.aspx?proj=135888

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03143-0.

A Single-Cell Survey of Cellular Heterogeneity in Human Great Saphenous Veins

Background: The great saphenous vein (GSV) is the most commonly used conduit for coronary arterial bypass graft. However, the status of the GSV, including metabolic dysfunction such as diabetes mellitus (DM) complication, is strongly associated with vein graft failure (VGF). To date, the molecular mechanism underlying VGF remains elusive. Detailed characterization of the cellular components and corresponding expression regulation in GSVs would be of great importance for clinical decision making to reduce VGF. Methods: To this end, we performed single-cell RNA sequencing to delineate cellular heterogeneity in three human GSV samples. Results: Scrutinization of cellular composition and expression revealed cell diversity in human GSVs, particularly endothelial cells (ECs). Our results unraveled that functional adaptation drove great expression differences between venous ECs and valvular ECs. For instance, cell surface receptor ACKR1 demarcated venous Ecs, whereas ACRK3/ACKR4 were exclusively expressed by valvular ECs. Differential gene expression analysis suggested that genes highly expressed in venous ECs were mainly involved in vasculature development and regulation of leukocyte adhesion, whereas valvular ECs have more pronounced expression of genes participating in extracellular matrix organization, ossification and platelet degranulation. Of note, pseudo-time trajectory analysis provided in silico evidence indicating that venous ECs, valvular ECs and lymphatic vessels were developmentally connected. Further, valvular ECs might be an importance source for lymphatic vessel differentiation in adults. Additionally, we found a venous EC subset highly expressing IL6, which might be associated with undesirable prognosis. Meanwhile, we identified a population of ANGPTL7+ fibroblasts (FBs), which may be profibrotic and involved in insulin resistance in human GSVs. Additionally, our data suggest that immune cells only accounted for a small fraction, most of which were macrophages. By assessing the intertwined remodeling in metabolic dysfunction that potentially increases the gene expression regulatory network in mural cells and leukocytes, we found that transcription factor KLF9 likely operated a proinflammatory program, inducing the transcription of metallothionein proteins in two mural cell subsets and proinflammatory immune cells. Lastly, cellular communication analysis revealed that proinflammatory signaling, including TRAIL, PVR, CSF and GDF, were uniquely activated in patients with metabolic dysfunction. Conclusions: Our results identified critical cell-specific responses and cellular interactions in GSVs. Beyond serving as a repertoire, this work illustrates multifactorial likelihood of VGF.

Role of Lipid-Lowering Therapy in Peripheral Artery Disease

Atherosclerosis is a multifactorial, lipoprotein-driven condition that leads to plaque formation within the arterial tree, leading to subsequent arterial stenosis and thrombosis that accounts for a large burden of cardiovascular morbidity and mortality globally. Atherosclerosis of the lower extremities is called peripheral artery disease and is a major cause of loss in mobility, amputation, and critical limb ischemia. Peripheral artery disease is a common condition with a gamut of clinical manifestations that affects an estimated 10 million people in the United States of America and 200 million people worldwide. The role of apolipoprotein B-containing lipoproteins, such as LDL and remnant lipoproteins in the development and progression of atherosclerosis, is well-established. The focus of this paper is to review existing data on lipid-lowering therapies in lower extremity atherosclerotic peripheral artery disease.

Renin-Angiotensin-Aldosterone System Inhibitors, Statins, and Beta-Blockers in Diabetic Patients With Critical Limb Ischemia and Foot Lesions

Medical therapy for secondary prevention is known to be under-used in patients with peripheral artery disease (PAD). Few data are available on the subgroup with critical limb ischemia (CLI). Prescription of cardiovascular preventive therapies was recorded at discharge in a large, prospective cohort of patients admitted for treatment of CLI and foot lesions, stratified for coronary artery disease (CAD) diagnosis. All patients were followed up for at least 1 year. The primary endpoint was major adverse cardiovascular events (MACE). 618 patients were observed for a median follow-up of 981 days. Renin-angiotensin-aldosterone system (RAAS) inhibitors, statins, beta-blockers, and antithrombotic drugs were prescribed in 52%, 80%, 51%, and 99% of patients, respectively. However, only 43% of patients received optimal medical therapy (OMT), defined as the combination of RAAS inhibitor plus statin plus at least one antithrombotic drug. It was observed that the prescription of OMT was not affected by the presence of a CAD diagnosis. On the other hand, it was noticed that the renal function affected the prescription of OMT. OMT was independently associated with MACE (HR 0.688, 95%CI 0.475-0.995, P = .047) and, after propensity matching, also with all-cause mortality (HR 0.626, 95%CI 0.409-0.958, P = .031). Beta-blockers prescription was not associated with any outcome. In conclusion, patients with critical limb ischemia are under-treated with cardiovascular preventive therapies, irrespective of a CAD diagnosis. This has consequences on their prognosis.

High lipoprotein(a) is associated with major adverse limb events after femoral artery endarterectomy

BACKGROUNDS AND AIMS

Elevated lipoprotein(a) (Lp[a]) has been identified as a causal risk factor for cardiovascular disease including peripheral arterial disease (PAD). Although Lp(a) is associated with the diagnosis of PAD, it remains elusive whether there is an association of Lp(a) with cardiovascular and limb events in patients with severe PAD.

METHODS

Preoperative plasma Lp(a) levels were measured in 384 consecutive patients that underwent iliofemoral endarterectomy and were included in the Athero-Express biobank. Our primary objective was to assess the association of Lp(a) levels with Major Adverse Limb Events (MALE). Our secondary objective was to relate Lp(a) levels to Major Adverse Cardiovascular Events (MACE) and femoral plaque composition that was acquired from baseline surgery.

RESULTS

During a median follow-up time of 5.6 years, a total of 225 MALE were recorded in 132 patients. Multivariable analysis, including history of peripheral intervention, age, diabetes mellitus, end stage renal disease and PAD disease stages, showed that Lp(a) was independently associated with first (HR of 1.36 (95% CI 1.02-1.82) p = .036) and recurrent MALE (HR 1.36 (95% CI 1.10-1.67) p = .004). A total of 99 MACE were recorded but Lp(a) levels were not associated with MACE.sLp(a) levels were significantly associated with a higher presence of smooth muscle cells in the femoral plaque, although this was not associated with MALE or MACE.

CONCLUSIONS

Plasma Lp(a) is independently associated with first and consecutive MALE after iliofemoral endarterectomy. Hence, in patients who undergo iliofemoral endarterectomy, Lp(a) could be considered as a biomarker to enhance risk stratification for future MALE.

Factors Affecting One-Year Outcomes After Major Lower Extremity Amputation in the Vascular Quality Initiative Amputation Registry

INTRODUCTION

Major lower extremity amputation (LEA) results in significant morbidity and mortality. This study identifies factors contributing to adverse long-term outcomes after major LEA.

STUDY DESIGN

Amputations in the Vascular Quality Initiative (VQI) long-term follow-up database from 2012 to 2017 were included. Multivariable logistic regression determined which significant patient factors were associated with 1-year mortality, long-term functional status, and progression to higher level amputation within 1 year.

RESULTS

3440 major LEAs were performed and a mortality rate of 19.9% was seen at 1 year. Logistic regression demonstrated that 1-year mortality was associated with post-op myocardial infarction (MI) (odds ratio (OR) 1.7, CI 1.02-2.97, P = .04), congestive heart failure (CHF) (OR 1.9, confidence interval (CI) 1.56-2.38, P < .001), hypertension (HTN) (OR 1.31, CI 1.00-1.72, P = .05), chronic obstructive pulmonary disease (COPD) (OR 1.36, CI 1.13-1.63, P < .001), and dependent functional status (OR 2.01, CI 1.67-2.41, P < .001). A decline in ambulatory status was associated with COPD (OR 1.36, CI 1.09-1.68, P = .006). Dependent functional status was protective against revision to higher level amputation (OR .18, CI .07-.45, P < .001).

CONCLUSION

In the VQI, 1-year mortality after major LEA is nearly 20% and associated with HTN, CHF, COPD, dependent functional status, and post-op MI. Decreased functional status at 1 year was associated with COPD, and progression to higher level amputation was less likely in patients with dependent functional status.

Current review with evolving management strategies in critical limb ischemia

Critical limb ischemia represents the end stage of peripheral artery disease, which is associated with impaired quality of life and considerable morbidity and mortality. Economical impact of the disease is huge with a substantial burden on patients, healthcare providers, and resources. Varied therapeutic strategies have been employed in the management of these patients. These patients usually have complex multilevel occlusive arteriopathy with significant comorbidities, rendering surgical interventions undesirable in many cases. Recent therapeutic advances with evolving endovascular techniques and gene or cell-based therapies have the potential to dramatically change the therapeutic outlook in these patients.

Association between Preoperative Indications and Outcomes after Major Lower Extremity Amputation

Despite aggressive limb salvage techniques, lower extremity amputation (LEA) is frequently performed. Major indications for LEA include ischemia and uncontrolled infection (UI). A review of the national Vascular Quality Initiative amputation registry was performed to analyze the influence of indication on outcomes after LEA. Retrospective review of the Vascular Quality Initiative LEA registry (2012–2017) identified all above- and below-knee amputations. Outcome measures included 30-day mortality, return to operating room (OR), postoperative myocardial infarctions, and postoperative SSI. Indications for surgery included ischemic rest pain, ischemic tissue loss (TL), acute limb ischemia (ALI), UI, and neuropathic TL. A total of 6701 patients met the inclusion criteria. The indications for surgery included TL (49.0%), UI (31.7%), ALI (8.0%), rest pain (6.6%), and neuropathic TL (2.3%). Patients with ALI had the highest 30-day mortality (12.0%) compared with TL (6.6%) and UI (6.4%) [ P < 0.001]. The highest rate of return to OR occurred in the UI group (12.6%) [ P < 0.001]. Multivariate analysis demonstrated that patients with UI have significantly higher rates of return to OR, whereas those with ALI have a 30-day mortality twice as high as other indications (both P < 0.001). These data can inform expectations after LEA based on the indications for surgery.

Functional prognosis of critical limb ischemia and efficacy of restoration of direct flow below the ankle

OBJECTIVE

Patients with critical limb ischemia have serious systemic comorbidities and are at high risk of impairment of limb function. In this study, we assessed the prognostic factors of limbs after revascularization.

METHODS

In this retrospective single-center cohort study, from April 2008 to December 2012, we treated 154 limbs of 121 patients with critical limb ischemia by the endovascular therapy-first approach based on the patients' characteristics. The primary end point was amputation-free survival. Secondary end points were patency of a revascularized artery, major adverse limb events, or death. Furthermore, we investigated the ambulatory status one year after revascularization as prognosis of limb function.

RESULTS

Endovascular therapy was performed in 85 limbs in 65 patients as the initial therapy (endovascular therapy group) and surgical reconstructive procedures (bypass group) were performed in 69 limbs in 56 patients. Early mortality within 30 days was not observed in either group. The primary patency rate was significantly better in the bypass group than in the endovascular therapy group ( p < 0.0001). Furthermore, the secondary patency rate was similar between the two groups ( p = 0.0096). There were no significant differences in amputation-free survival and major adverse limb event between the two groups. Univariate analysis showed that ulcer healing ( p < 0.0001), no hypoalbuminemia ( p = 0.0019), restoration of direct flow below the ankle ( p = 0.0219), no previous cerebrovascular disease ( p = 0.0389), and Rutherford 4 ( p = 0.0469) were predictive factors for preservation of ambulatory status one year after revascularization. In multivariate analysis, ulcer healing ( p < 0.0001) and restoration of direct flow below the ankle ( p = 0.0060) were significant predictors.

CONCLUSIONS

Ulcer healing and restoration of direct flow below the ankle are independently associated with prognosis of limb functions in patients who undergo infrainguinal arterial reconstruction.

Association of Race with Long-Term Outcomes in Patients Undergoing Popliteal and Infra-Popliteal Percutaneous Peripheral Arterial Interventions

BACKGROUND

Race-related differences in clinical features, presentation, treatment and outcomes of patients with various cardiovascular diseases have been reported in previous studies. However, the long-term outcomes in black versus white patients with popliteal and/or infra-popliteal peripheral arterial disease (PAD) undergoing percutaneous peripheral vascular interventions (PVI) are not well known.

METHODS AND RESULTS

We retrospectively evaluated long-term outcomes in 696 patients (263 blacks and 433 whites) who underwent PVI for popliteal and/or infra-popliteal PAD at our institution between 2007 and 2012. When compared to white patients, black patients were younger (70 ± 11 vs. 72 ± 11; P = 0.002) and had more comorbidities: higher creatinine (2.04 ± 2.08 vs. 1.33 ± 1.16; P < 0.0001) with more ESRD (19% vs. 6%; P < 0.0001) and more diabetes (64% vs. 55%; P = 0.004). At mean follow-up of 36 ± 20 months, there was no statistically significant difference between black and white patients either in all-cause mortality (29% vs. 32%; P = 0.38) or in major amputation (4.4% vs. 4.2%; P = 0.88), respectively. In a multi-variate Cox proportional hazard model, repeat ipsilateral percutaneous revascularization or bypass were lower in black patients (HR = 0.64 [95% CI 0.46-0.89]; P = 0.007) and major adverse vascular events (MAVE) were lower in black patients as well (HR = 0.7 [95% CI 0.56-0.89]; P = 0.003).

CONCLUSION

Black patients undergoing popliteal or infra-popliteal PVI had similar mortality and major amputation, but lower repeat revascularization and MAVE compared to white patients. These data support the use of PVI in minorities despite higher baseline comorbidities and call for more research to understand the mechanisms underlying the high mortality irrespective of race.

Prognostic factors of ulcer healing and amputation-free survival in patients with critical limb ischemia

Objective

A multidisciplinary approach is required to treat critical limb ischemia. We determined the poor prognostic factors of ischemic ulcer healing after optimal arterial revascularization, and assessed the efficacy of the medication therapy using cilostazol, which is a selective inhibitor of phosphodiesterase 3.

Methods

In this retrospective, single-center, cohort study, 129 limbs that underwent infrainguinal arterial revascularization for Rutherford class 5 critical limb ischemia were reviewed. The primary end point was the ulcer healing time after arterial revascularization. The secondary end point was the amputation-free survival rate.

Results

Of the 129 limbs, endovascular therapy was performed in 69 limbs, and surgical reconstructive procedures were performed in 60 limbs for initial therapy. Complete ulcer healing was achieved in 95 limbs (74%). The median ulcer healing time was 90 days. In multivariate analysis, no cilostazol use significantly inhibited ulcer healing ( p = 0.0114). A white blood cell count >10,000 ( p = 0.0185), a major defect after debridement ( p = 0.0215), and endovascular therapy ( p = 0.0308) were significant poor prognostic factors for ulcer healing. Additionally, ischemic heart disease ( p < 0.0001), albumin levels <3 g/dl ( p = 0.0016), no cilostazol use ( p = 0.0078), and a major defect after debridement ( p = 0.0208) were significant poor prognostic factors for amputation-free survival rate.

Conclusions

Ulcer healing within 90 days after arterial revascularization is impaired by no cilostazol use, a white blood cell count >10,000, a major defect after debridement, and endovascular therapy. Furthermore, cilostazol improves amputation-free survival rate in patients with critical limb ischemia.

Association of Statin Dose With Amputation and Survival in Patients With Peripheral Artery Disease

BACKGROUND

Statin dose guidelines for patients with peripheral artery disease (PAD) are largely based on coronary artery disease and stroke data. The aim of this study is to determine the effect of statin intensity on PAD outcomes of amputation and mortality.

METHODS

Using an observational cohort study design and a validated algorithm, we identified patients with incident PAD (2003-2014) in the national Veterans Affairs data. Highest statin intensity exposure (high-intensity versus low-to-moderate-intensity versus antiplatelet therapy but no statin use) was determined within 1 year of diagnosis of PAD. Outcomes of interest were lower extremity amputations and death. The association of statin intensity with incident amputation and mortality was assessed with Kaplan-Meier plots, Cox proportional hazards modeling, propensity score-matched analysis, and sensitivity and subgroup analyses, as well, to reduce confounding.

RESULTS

In 155 647 patients with incident PAD, more than a quarter (28%) were not on statins. Use of high-intensity statins was lowest in patients with PAD only (6.4%) in comparison with comorbid coronary/carotid disease (18.4%). Incident amputation and mortality risk declined significantly with any statin use in comparison with the antiplatelet therapy-only group. In adjusted Cox models, the high-intensity statin users were associated with lower amputation risk and mortality in comparison with antiplatelet therapy-only users (hazard ratio, 0.67; 95% confidence interval, 0.61-0.74 and hazard ratio, 0.74; 95% confidence interval, 0.70-0.77, respectively). Low-to-moderate-intensity statins also had significant reductions in the risk of amputation and mortality (hazard ratio amputation, 0.81; 95% confidence interval, 0.75- 0.86; hazard ratio death, 0.83; 95% confidence interval, 0.81-0.86) in comparison with no statins (antiplatelet therapy only), but effect size was significantly weaker than the high-intensity statins (P<0.001). The association of high-intensity statins with lower amputation and death risk remained significant and robust in propensity score-matched, sensitivity, and subgroup analyses.

CONCLUSIONS

Statins, especially high-intensity formulations, are underused in patients with PAD. This is the first population-based study to show that high-intensity statin use at the time of PAD diagnosis is associated with a significant reduction in limb loss and mortality in comparison with low-to-moderate-intensity statin users, and patients treated only with antiplatelet medications but not with statins, as well.

Surgeon, not institution, case volume is associated with limb outcomes after lower extremity bypass for critical limb ischemia in the Vascular Quality Initiative

OBJECTIVE

Studies from large administrative databases have demonstrated associations between institutional case volume and outcomes after lower extremity bypass (LEB). We hypothesized that increased institutional and surgeon volume would be associated with improved outcomes after LEB. Using a national, prospectively collected clinical database, the objective of this study was to determine the effects of both surgeon and institutional volume on outcomes after LEB.

METHODS

The Vascular Quality Initiative (VQI) was queried to identify all LEBs for critical limb ischemia or claudication between 2004 and 2014. Average annual case volume was calculated by dividing an institution's or surgeon's total LEB volume by the number of years they reported to the VQI. Institutional and surgeon volumes were analyzed as continuous variables to determine the impact of volume on major adverse cardiac events (MACEs), major adverse limb events (MALEs), graft patency, and amputation-free survival. Hierarchical regression models were used with cases clustered by surgeon and center. Time-dependent outcomes were evaluated with multivariable shared frailty Cox proportional hazards models.

RESULTS

From 2004 to 2014, there were 14,678 LEB operations performed at 114 institutions by 587 surgeons. Average annual institutional volume ranged from 1.0 to 137.5 LEBs per year, with a median of 26.9 (interquartile range, 14-45.3). Average annual surgeon volume ranged from 1 to 52 LEBs per year with a median of 5.7 (interquartile range, 2.5-9.3). Institutional LEB volume was not associated with MACEs or MALEs or with loss of patency. However, average annual surgeon volume was independently associated with reduced MALEs and improved primary patency. Institutional and surgeon volume did not predict MACEs.

CONCLUSIONS

In contradistinction to previous studies, there was no relationship in this study between institutional LEB volume and outcomes after LEB. However, greater average annual surgeon volume was associated with improved primary patency and decreased risk of MALEs. Open LEB remains a safe and effective procedure for limb salvage. Limb-related outcomes in critical limb ischemia and claudication will be optimized if surgeons maintain adequate volume of LEB.

Lower extremity bypass for critical limb ischemia decreases major adverse limb events with equivalent cardiac risk compared with endovascular intervention

OBJECTIVE

Lower extremity bypass (LEB) has traditionally been the "gold standard" in the treatment of critical limb ischemia (CLI). Infrainguinal endovascular intervention (IEI) has become more commonly performed than LEB, but comparative outcomes are limited. We sought to compare rates of major adverse limb events (MALEs) and major adverse cardiovascular events (MACEs) after LEB and IEI in a propensity score-matched, national cohort of patients with CLI.

METHODS

The National Surgical Quality Improvement Program (NSQIP) vascular targeted files (2011-2014) for LEB and IEI were merged. CLI patients were identified by ischemic rest pain or tissue loss. Patients were matched on a 1:1 basis for propensity to undergo LEB or IEI. Primary outcomes were 30-day MALEs and MACEs. Within the propensity-matched cohort, multivariate logistic regression was used to identify independent predictors of MALEs and MACEs.

RESULTS

A total of 13,294 LEBs and IEIs were identified, with 8066 cases performed for CLI. Propensity matching identified 3848 cases (1924 per group). There were no differences in preoperative variables between the propensity-matched LEB and IEI groups (all P > .05). At 30 days, rates of MALEs were significantly lower in the LEB group (9.2% LEB vs IEI 12.2%; P = .003). On multivariate logistic regression, bypass with single-segment saphenous vein vs IEI (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.54-0.92; P = .01), bypass with alternative conduit (prosthetic, spliced vein, or composite) vs IEI (OR, 0.7; 95% CI, 0.56-0.98; P = .04), antiplatelet therapy (OR, 0.8; 95% CI, 0.58-1.00; P = .049), and statin therapy (OR, 0.8; 95% CI, 0.62-0.99; P = .04) were protective against MALEs, whereas infrageniculate intervention (OR, 1.4; 95% CI, 1.09-1.72; P = .01) and a history of prior bypass of the same arterial segment (OR, 1.8; 95% CI, 1.41-2.41; P <. 0001) were predictive. Rates of 30-day MACEs were not significantly different (4.9% LEB vs 3.7% IEI; P = .07) between the groups. Independent predictors of MACEs included age (OR, 1.02; 95% CI, 1.01-1.04; P = .01), steroid use (OR, 1.8; 95% CI, 1.08-2.99; P = .03), congestive heart failure (OR, 1.7; 95% CI, 1.00-1.96; P = .02), beta blocker use (OR, 1.6; 95% CI, 1.09-1.43; P = .01), dialysis (OR, 2.3; 95% CI, 1.55-3.45; P < .0001), totally dependent functional status (OR, 3.1; 95% CI, 1.25-7.58; P = .02), and suboptimal conduit for LEB compared with IEI (OR, 1.6; 95% CI, 1.08-2.36; P = .02).

CONCLUSIONS

Within this large, propensity-matched, national cohort, LEB predicted lower risk-adjusted 30-day MALE rate compared with IEI. Furthermore, there was no difference in 30-day MACE rate between the groups despite higher inherent risk with open surgical procedures. Therefore, this study supports the effectiveness and primacy of LEB for revascularization in CLI.

Infrainguinal open reconstruction: a review of surgical considerations and expected outcomes

Infrainguinal arterial occlusive disease can lead to potentially disabling and limb-threatening conditions. Revascularization may be indicated for claudication, rest pain, or tissue loss. Although endovascular interventions are becoming more prevalent, open surgeries such as endarterectomy and bypass are still needed and performed regularly. Open reconstruction has been associated with postoperative morbidity, both at the local and at the systemic levels. Local complications include surgical site infections (SSIs 0-5.3%), graft failure (12-60%), and amputation (5.7-27%), and more systemic issues include cardiac (2.6-18.4%), respiratory (2.5%), renal (4%), neurovascular (1.5%), and thromboembolic (0.2-1%) complications. While such outcomes present an additional challenge to the postoperative management of surgical patients, it may be possible to minimize their occurrence through careful risk stratification and preoperative assessment. Therefore, individualized selection of candidates for open repair requires weighing the need for intervention against the likelihood of adverse outcomes based on preoperative risk factors. This review provides an overview of open reconstruction, focusing on identifying the clinical indications for surgery and perioperative morbidity and mortality.

Pre-operative predictors of poor outcomes in patients undergoing surgical lower extremity revascularisation - Retrospective cohort study

BACKGROUND

Surgical lower extremity revascularisation (LER) can lead to poor outcomes that include delayed hospital discharge, in-hospital mortality, major amputations and readmissions. The aim of this study was to identify pre-operative predictors associated with these poor clinical outcomes.

MATERIALS AND METHODS

All patients (n = 635; mean age 69; male 67.4%) who underwent surgical LER over a 5 year period in a single tertiary vascular institution were identified. Patients considered to have suffered a poor outcome (Group A) included all in-hospital mortality and major amputations, delayed discharges with a length of stay (LOS) over one standard deviation above the mean or any readmission under any specialty within 12 months. Group A included 247 patients (38.9%) and the good outcome group included the remaining 388 patients (61.1%) from which a sample of 99 patients were selected as controls (Group B).

RESULTS

Mean LOS for the entire study group was 14.4 ± 17.5 days, 12 month readmission rate was 29.1% and in-hospital mortality and major amputation rate was 2.7% and 1.4%, respectively. Pre-admission residence other than own home (OR 9.0; 95% CI 1.2-70.1; P = 0.036), atherosclerotic disease burden (OR 2.2; 95% CI 1.3-3.8; P = 0.003) and tissue loss (OR 3.0; 95% CI 1.6-5.3; P < 0.001) were identified as independent, statistically significant pre-operative predictors of poor outcome. Following discharge, group B patients had a significantly higher rate of amputation free survival and graft infection free survival (P < 0.001) compared to group A.

CONCLUSION

Recognition of pre-operative predictors of poor outcome should inform case selection and identify high risk patients requiring intensive perioperative optimisation and post discharge follow up.

Results for primary bypass versus primary angioplasty/stent for lower extremity chronic limb-threatening ischemia

BACKGROUND

Long-term results comparing percutaneous transluminal angioplasty with or without stenting (PTA/S) and open surgical bypass for chronic limb-threatening ischemia (CLTI) in patients who have had no prior intervention are lacking.

METHODS

All patients undergoing a first-time lower extremity revascularization for CLTI by vascular surgeons at our institution from 2005 to 2014 were retrospectively reviewed. Outcomes included perioperative complications, wound healing, restenosis, primary patency, reintervention, major amputation, RAS events (ie, reintervention, major amputation, or stenosis), and mortality. Outcomes were evaluated using χ², Kaplan-Meier, and Cox regression analyses.

RESULTS

Of the 2869 total lower extremity revascularizations performed between 2005 and 2014, there were 1336 that fit our criteria of a first-time lower extremity intervention for CLTI (668 bypass procedures and 668 PTA/S procedures). Bypass patients were younger (71 vs 72 years; P = .02) and more often male (62% vs 56%; P < .02). Total mean hospital length of stay (LOS) was significantly longer after a first-time bypass (10 vs 8 days; P < .001), as were mean preoperative LOS (4 vs 3 days; P < .01) and postoperative LOS (7 vs 5 days; P < .001). There was no difference in perioperative mortality (3% vs 3%; P = .63). Surgical site infection occurred in 10% of bypass patients. Freedom from reintervention was significantly higher in patients undergoing a first-time bypass procedure (62% vs 52% at 3 years; P = .04), as was freedom from restenosis (61% vs 45% at 3 years; P < .001). Complete wound healing at 6-month follow-up was significantly better after an initial bypass (43% vs 36%; P < .01). A Cox regression model of all patients showed that reintervention was predicted by a first-time PTA/S (hazard ratio, 1.6; 95% confidence interval, 1.3-2.1) and both preoperative femoropopliteal TransAtlantic Inter-Society Consensus (TASC) C and TASC D lesions (2.0 [1.3-3.1] and 1.8 [1.3-2.7], respectively). Major amputation among all patients was predicted by an initial presentation of gangrene (2.5 [1.3-5.0]), dialysis dependence (1.9 [1.3-2.9]), diabetes (2.0 [1.1-3.8]), and preoperative femoropopliteal TASC D lesions (2.1 [1.1-4.0]) and was not predicted by procedure type.

CONCLUSIONS

In this retrospective analysis, bypass for the primary treatment of CLTI showed improved 6-month wound healing, higher freedom from restenosis, improved patency rates, significantly fewer reinterventions, and higher survival than PTA/S within 3 years; however, a bypass-first approach was associated with increased total hospital LOS and wound infection. Perioperative mortality and amputation rates were similar between procedure types.

Predictors of Postoperative Outcome in Patients with Lower Limb Surgical Revascularization

Objective: In patients with critical limb ischemia who undergone revascularization procedures, the assessment of risk factors that may affect the postoperative outcome is of great importance. The main objective in this study is to assess the utility of two specific risk scores, the Finnvasc score and the modified Prevent III score.

Methods: We evaluated the applicability of these two risk scores in 150 patients who undergone an unilateral infrainguinal surgical revascularization procedure. The receiver operating characteristic curve analysis was used to estimate the predictive value of the scoring methods. A comparison between the risk scores, determine the areas under the curve. Medium-term prediction ability was analyzed for both scoring methods.

Results: The area under the curve of Finnvasc score for predicting amputation was 0.739 (95%CI:0.661-0.807) and of the modified PIII score 0.713 (95%CI:0.633-0.784); for restenosis we obtained 0.528 (95%CI:0.444-0.611), respectively 0.529 (95%CI:0.445-0.612) and for thrombosis 0.628 (95%CI:0.544-0.706) and 0.556 (95%CI:0.472-0.638), demonstrating that the Finnvasc score performs better in overall prediction. Heart failure is a strong independent predictor of amputation (p=0.0001, OR=26.90; 95%CI:5.81-124.2), restenosis (p=0.0003, OR=4.80; 95%CI:1.96-11.8) and mortality (p=0.01, OR=7.16; 95%CI:1.33-38.52).

Conclusions: The accuracy of the two risk scoring methods in predicting the medium-term outcome of patients undergoing surgical infrainguinal revascularization is acceptable. The Finnvasc score is easier to be applied to the characteristics of our patients.

Vein graft failure: from pathophysiology to clinical outcomes

Occlusive arterial disease is a leading cause of morbidity and mortality worldwide. Aside from balloon angioplasty, bypass graft surgery is the most commonly performed revascularization technique for occlusive arterial disease. Coronary artery bypass graft surgery is performed in patients with left main coronary artery disease and three-vessel coronary disease, whereas peripheral artery bypass graft surgery is used to treat patients with late-stage peripheral artery occlusive disease. The great saphenous veins are commonly used conduits for surgical revascularization; however, they are associated with a high failure rate. Therefore, preservation of vein graft patency is essential for long-term surgical success. With the exception of 'no-touch' techniques and lipid-lowering and antiplatelet (aspirin) therapy, no intervention has hitherto unequivocally proven to be clinically effective in preventing vein graft failure. In this Review, we describe both preclinical and clinical studies evaluating the pathophysiology underlying vein graft failure, and the latest therapeutic options to improve patency for both coronary and peripheral grafts.

The Concept of Risk Assessment and Being Unfit for Surgery

The concept of risk assessment and the identification of surgical unfitness for vascular intervention is a particularly controversial issue today as the minimally invasive surgical population has increased not only in volume but also in complexity (comorbidity profile) and age, requiring an improved pre-operative selection and definition of high risk. A practical step by step (three steps, two points for each) approach for surgical risk assessment is suggested in this review. As a general rule, the identification of a "high risk" patient for vascular surgery follows a step by step process where the risk is clearly defined, quantified (when too "high"?), and thereby stratified based on the procedure, the patient, and the hospital, with the aid of predictive risk scores. However, there is no standardized, updated, and objective definition for surgical unfitness today. The major gap in the current literature on the definition of high risk in vascular patients explains the lack of sound validated predictive systems and limited generalizability of risk scores in vascular surgery. In addition, the concept of fitness is an evolving tool and many traditional high risk criteria and definitions are no longer valid. Given the preventive purpose of most vascular procedures performed in elderly asymptomatic patients, the decision to pursue or withhold surgery requires realistic estimates not only regarding individual peri-operative mortality, but also life expectancy, healthcare priorities, and the patient's primary goals, such as prolongation of life versus maintenance of independence or symptom relief. The overall "frailty" and geriatric risk burden, such as cognitive, functional, social, and nutritional status, are variables that should be also included in the analyses for stratification of surgical risk in elderly vascular patients.

Evidence for the Use of Multiple Mechanisms by Herpes Simplex Virus-1 R7020 to Inhibit Intimal Hyperplasia

Intimal hyperplasia (IH) is the primary cause of vein bypass graft failure. The smooth muscle cell (SMC) is a key element of IH as it phenotypically switches from a contractile to a synthetic state which can become pathological. R7020, which is an engineered strain of Herpes Simplex Virus-1, inhibits IH in animal models. Although it has many characteristics which make it a strong candidate for use as a prophylactic agent how it inhibits IH is not well understood. The objective of this study was to identify modes of action used by R7020 to function in blood vessels that may also contribute to its inhibition of IH. The cytopathic effect of R7020 on SMCs was determined in vitro and in a rabbit IH model. In vitro assays with R7020 infected SMCs were used to quantify the effect of dose on the release kinetics of the virus as well as the effects of R7020 on cell viability and the adhesion of peripheral blood mononuclear cells (PBMCs) to SMCs in the absence and presence of tumor necrosis factor alpha (TNF-α). The observed cytopathic effect, which included R7020 positive filopodia that extend from cell to cell and the formation of syncytia, suggests that R7020 remains cell associated after egress and spreads cell to cell instead of by diffusion through the extracellular fluid. This would allow the virus to rapidly infect vascular cells while evading the immune system. The directionality of the filopodia in vivo suggests that the virus preferentially travels from the media towards the intima targeting SMCs that would lead to IH. The formation of syncytia would inhibit SMC proliferation as incorporated cells are not able to multiply. It was also observed that R7020 induced the fusion of PBMCs with syncytia suggesting the virus may limit the effect of macrophages on IH. Furthermore, R7020 inhibited the proliferative effect of TNF-α, an inflammatory cytokine associated with increased IH. Thus, the results of this study suggest that R7020 inhibits IH through multiple mechanisms.

Surgical Intervention for Peripheral Arterial Disease

The prevalence of peripheral arterial disease (PAD) is increasing worldwide, with recent global estimates exceeding 200 million people. Advanced PAD leads to a decline in ambulatory function and diminished quality of life. In its most severe form, critical limb ischemia, rest pain, and tissue necrosis are associated with high rates of limb loss, morbidity, and mortality. Revascularization of the limb plays a central role in the management of symptomatic PAD. Concomitant with advances in the pathogenesis, genetics, and medical management of PAD during the last 20 years, there has been an ongoing evolution of revascularization options. The increasing application of endovascular techniques has resulted in dramatic changes in practice patterns and has refocused the question of which patients should be offered surgical revascularization. Nonetheless, surgical therapy remains a cornerstone of management for advanced PAD, providing versatile and durable solutions to challenging patterns of disease. Although there is little high-quality comparative effectiveness data to guide patient selection, existing evidence suggests that outcomes are dependent on definable patient factors such as distribution of disease, status of the limb, comorbid conditions, and conduit availability. As it stands, surgical revascularization remains the standard against which emerging percutaneous techniques are compared. This review summarizes the principles of surgical revascularization, patient selection, and expected outcomes, while highlighting areas in need of further research and technological advancement.

Acute reductions in mechanical wall strain precede the formation of intimal hyperplasia in a murine model of arterial occlusive disease

OBJECTIVE

Intimal hyperplasia (IH) continues to plague the durability of vascular interventions. Employing a validated murine model, ultrasound biomicroscopy, and speckle-tracking algorithms, we tested the hypothesis that reduced cyclic arterial wall strain results in accentuated arterial wall IH.

METHODS

A 9-0 suture was tied around the left mouse (n = 10) common carotid artery and a 35-gauge (outer diameter = 0.14 mm) blunt mandrel. We previously showed that mandrel removal results in a ∼78% reduction in diameter and ∼85% reduction in flow, with subsequent delayed induction of IH by day 28. Preoperative, postoperative day-4 (before measurable IH), and postoperative day-27 circumferential wall strains were measured in locations 1, 2, and 3 mm proximal to the stenosis and in the same locations on the contralateral (nonstenosed) carotid. At postoperative day 28, arteries were perfusion fixed and arterial wall morphology was assessed microscopically in the same regions.

RESULTS

Strains were the same in all locations preoperatively. Wall strain was decreased in all regions proximal to the stenosis by day 4 (0.26 ± 0.01 to 0.11 ± 0.02; P < .001), while strains remained unchanged for the contralateral artery (P = .45). No statistical regional differences in mean strain or IH were noted at any time point for the experimental or contralateral artery. Based on the median, regions were divided into those with low strain (≤0.1) and high strain (>0.1). Average preoperative strains in both groups were the same (0.27 ± 0.09 and 0.27 ± 0.08). All segments in the low-strain group (n = 13) demonstrated significant IH formation by day 28, while only 31% of the high strain group demonstrated any detectable IH at day 28. (Mean low-strain intimal thickness = 32 ± 20 μm, high strain = 8.0 ± 16 μm; P < .01). Changes in cross-sectional area at diastole drove the reduction in strain in the low-strain group, increasing significantly from preoperatively to day 4 (P = .04), while lumen cross-section at systole remained unchanged (P = .46). Cross-sectional area at diastole and systole in the high-strain group remained unchanged from preoperatively to day 4 (P = .67).

CONCLUSIONS

Early reduction in arterial wall strain is associated with subsequent development of hemodynamically induced IH.

The impact of preoperative statin therapy on open and endovascular abdominal aortic aneurysm repair outcomes

OBJECTIVES

This study evaluated the utilization of preoperative statins and their impact on perioperative outcomes in patients undergoing open or endovascular aortic repair.

METHODS

Patients ≥50 years of age with non-ruptured abdominal aortic aneurysm repair were identified in MedPAR files 2007-2008 utilizing ICD-9-CM codes. Preoperative statins use was identified using National Drug Codes in Part D. Chi-square test, multivariable logistic regression, Kaplan-Meier and Cox regression modeling were performed.

RESULTS

In all, 19,323 patients were identified undergoing abdominal aortic aneurysm repair (14,602 endovascular aortic repair and 4721 open aortic repair); 9913 (50.3%) used statins before surgery. Bivariate analysis demonstrated lower rates of hospital, 30-, 90-day and 1-year mortality in patients with statins compared to those without statins after endovascular aortic repair (1.0% vs. 1.45%, p = 0.01; 1.51% vs. 2.3%, p = 0.0004; 3.05% vs. 4.66%, p < 0.0001; 7.91% vs. 11.56%, p < 0.0001, respectively). Multivariable logistic regression adjusting for age, gender, race, comorbidities and procedure demonstrated preoperative statins use was associated with a mortality reduction at 90-days postoperatively (odds ratio = 0.80; 95% CI 0.70-0.91, p = 0.0014) and 1-year postoperatively (odds ratio = 0.76; 95% CI 0.69-0.84, p = 0.0001).

CONCLUSIONS

Only half of the patients undergoing abdominal aortic aneurysm repair were prescribed preoperative statins. After adjustment, statins were significantly associated with improved survival during 1 year after surgery and a decreased incidence of lower extremity embolic complications after endovascular aortic repair. These data support a beneficial role of statin use prior to surgery for patients undergoing abdominal aortic aneurysm repair. Further prospective studies are needed to assess the benefit of statins in the perioperative period after 365 days.

The impact of prolonged lower limb ischemia on amputation, mortality, and functional status: the FRIENDS registry

BACKGROUND

Peripheral artery disease (PAD) is a major cause of cardiovascular ischemic events and amputation. Knowledge gaps exist in defining and measuring key factors that predict these events. The objective of this study was to assess whether duration of limb ischemia would serve as a major predictor of limb and patient survival.

METHODS

The FReedom from Ischemic Events: New Dimensions for Survival (FRIENDS) registry enrolled consecutive patients with limb-threatening peripheral artery disease at a single tertiary care hospital. Demographic information, key clinical care time segments, functional status and use of revascularization, and pharmacotherapy data were collected at baseline, and vascular ischemic events, cardiovascular mortality, and all-cause mortality were recorded at 30 days and 1 year.

RESULTS

A total of 200 patients with median (interquartile range) age of 76 years (65-84 years) were enrolled in the registry. Median duration of limb ischemia was 0.75 days for acute limb ischemia (ALI) and 61 days for chronic critical limb ischemia (CLI). Duration of limb ischemia of <12, 12 to 24, and >24 hours in patients with ALI was associated with much higher rates of first amputation (P = .0002) and worse amputation-free survival (P = .037). No such associations were observed in patients with CLI.

CONCLUSIONS

For individuals with ischemic symptoms <14 days, prolonged limb ischemia is associated with higher 30-day and 1-year amputation, systemic ischemic event rates, and worse amputation-free survival. No such associations are evident for individuals with chronic CLI. These data imply that prompt diagnosis and revascularization might improve outcomes for patients with ALI.

Quality of care among patients undergoing lower extremity revascularization

BACKGROUND

Compliance with guidelines for treating patients with peripheral artery disease (PAD) lags compliance for treating patients with coronary artery disease. We assessed the gap between guidelines and practice for patients with PAD who underwent lower extremity revascularization (LER) at our institution from 2007 to 2010.

METHODS

Quality of care (QoC) was calculated by measuring provider performance on four indicators (antiplatelet therapy, dyslipidemia management, control of hypertension, and diabetes) derived from the ACCF/AHA PAD guidelines. The QoC score was calculated at the time of admission and at time of discharge for each patient, and reflects the proportion of indicated treatments received.

RESULTS

Patients (n = 734, mean age 70±11, female 51%) were followed for a mean of 2.0±1.4 years (range 0-5.7) following LER. The indication for LER was claudication (24.8%), rest pain (16.7%), and tissue loss (58.4%). The percentage of patients with a perfect QoC score increased significantly during hospital admission (11% to 21%, p < 0.001). Significant multivariate predictors of perfect QoC score included race/ethnicity, Charlson score, severity of LE ischemia, and observation period (admission, discharge). Multivariate analysis demonstrated that age>75 years, heart failure, chronic kidney disease, rest pain, and tissue loss-but not compliance with four guideline-based therapies-were associated with decreased freedom from the composite endpoint of major amputation, repeat revascularization, and death.

CONCLUSIONS

Although adherence to guidelines improved over time, we found a significant gap between guidelines and practice for this cohort of patients at increased risk for adverse cardiovascular events.

Antiplatelet Therapy for Peripheral Arterial Disease and Critical Limb Ischemia

Antiplatelet therapy is invariably prescribed for patients with peripheral arterial disease and critical limb ischemia, and numerous major society guidelines espouse their use, but high-quality data in this high-risk and challenging patient population are often lacking. This article summarizes the major guidelines for antiplatelet therapy, reviews the major studies of antiplatelet therapy in peripheral arterial disease (including data for aspirin, clopidogrel, dipyridamole, cilostazol, and prostanoids), and offers perspective on the potential benefits of ticagrelor, vorapaxar, and rivaroxaban. The review concludes with a discussion of the relative lack of efficacy that antiplatelet therapy has shown in regard to peripheral vascular outcomes.

Defining risks and predicting adverse events after lower extremity bypass for critical limb ischemia

Successful treatment of patients with critical limb ischemia (CLI), hinges on the adequacy of revascularization. However, CLI is associated with a severe burden of systemic atherosclerosis, and patients often suffer from multiple cardiovascular comorbidities. Therefore, CLI patients in general represent a cohort at increased risk for procedural complications and adverse events. Although endovascular therapy represents a minimally invasive alternative to open surgical bypass, the durability of surgical reconstruction is superior, and it remains the "gold standard" approach to revascularization in CLI. Therefore, selection of the optimal treatment modality for individual patients requires careful consideration of the procedural risks and likelihood of adverse events associated with surgery. Individualized decision-making with regard to revascularization strategy requires a comprehensive understanding of the likelihood of adverse outcomes after major surgery. Here we review the risks of surgical bypass in patients with CLI, with particular emphasis on the identification of preoperative variables that predict poor outcome.

Trends in the incidence, treatment, and outcomes of acute lower extremity ischemia in the United States Medicare population

OBJECTIVE

Acute lower extremity ischemia (ALI) is a common vascular surgery emergency associated with high rates of morbidity and mortality. The purpose of this study was to assess contemporary trends in the incidence of ALI, the methods of treatment, and the associated mortality and amputation rates in the U.S. Medicare population.

METHODS

This was an observational study using Medicare claims data between 1998 and 2009. Outcomes examined included trends in the incidence of ALI; trends in interventions for ALI; and trends in amputation, mortality, and amputation-free survival rates.

RESULTS

Between 1998 and 2009, the incidence of hospitalization for ALI decreased from 45.7 per 100,000 to 26.0 per 100,000 (P for trend < .001). The percentage of patients undergoing surgical intervention decreased from 57.1% to 51.6% (P for trend < .001), whereas the percentage of patients undergoing endovascular interventions increased from 15.0% to 33.1% (P for trend < .001). In-hospital mortality rates decreased from 12.0% to 9.0% (P for trend < .001), whereas 1-year mortality rates remained stable at 41.0% and 42.5% (P for trend not significant). In-hospital amputation rates remained stable at 8.1% and 6.4% (P for trend not significant), whereas 1-year amputation rates decreased from 14.8% to 11.0% (P for trend < .001). In-hospital amputation-free survival after hospitalization for ALI increased from 81.2% to 85.4% (P for trend < .001); however, 1-year amputation-free survival remained unchanged.

CONCLUSIONS

Between 1998 and 2009, the incidence of ALI among the U.S. Medicare population declined significantly, and the percentage of patients treated with endovascular techniques markedly increased. During this time, 1-year amputation rates declined. Furthermore, although in-hospital mortality rates declined after presentation with ALI, 1-year mortality rates remained unchanged.

Therapeutic approach to CLI with tissue loss--a comparative prospective cohort study in Finland and Japan

BACKGROUND

To compare the demographics, chosen treatment options, and 1-year outcome of patients with severe critical limb ischemia (Fontaine IV) in 2 different patient cohorts.

METHODS

A total of 118 consecutive patients with an ischemic tissue lesion in a lower extremity referred for the first time to the vascular surgery outpatient clinic of Helsinki University Hospital and 96 patients referred to the Division of Vascular Surgery of the Tokyo Medical and Dental University Hospital were included in this comparative analysis. Kaplan-Meier estimates were used to assess survival, leg salvage, and amputation-free survival (AFS). Propensity score analysis was used to adjust for differences between the study groups.

RESULTS

The median age of the study cohorts was greater in Finland than in Japan (80 vs. 69 years, P < 0.001). The prevalence of coronary artery disease and hypertension were greater in the Finnish cohort (72% vs. 41%, P < 0.001 and 86% vs. 51%, P < 0.001, respectively). The prevalence of male gender (77% vs. 42%, P < 0.001), cerebrovascular disease (35% vs. 20%, P = 0.015), end-stage renal disease (35% vs. 5%, P < 0.001), and current smoking (64% vs. 21%, P < 0.001) was greater in the Japanese cohort. The prevalence of diabetes did not differ between the cohorts (52% vs. 47%, P = 0.286). The proportion of independently ambulant patients at referral was greater in Finland (80% vs. 54%, P < 0.001). In Helsinki and Tokyo, the initial treatment was bypass, an endovascular procedure, conservative treatment, and amputation in 42% vs. 41%, 24% vs. 14%, 24% vs. 41%, and 10% vs. 5% of the cases, respectively. One-year survival, leg salvage, and AFS were 65% vs. 71% (P = 0.326), 82% vs. 74% (P = 0.216), and 59% vs. 55% (P = 0.573) in the Finnish and Japanese cohorts, respectively. AFS was significantly better in ambulant than in nonambulant patients in the combined data (68% vs. 36%, P < 0.001). Adjusted propensity score analysis showed no statistical difference in survival between the study cohorts.

CONCLUSIONS

The pattern of comorbid conditions in these 2 patient cohorts is significantly different, but the outcome did not differ significantly between cohorts.

Preoperative Statins and Limb Salvage After Lower Extremity Revascularization in the Medicare Population

Background—

Statins stabilize atherosclerotic plaque, decrease mortality after surgical procedures, and are linked to anti-inflammatory effects. The objective of this study was to evaluate preoperative administration of statins and longitudinal limb salvage after lower extremity endovascular revascularization and lower extremity open surgery.

Methods and Results—

Patients were selected from 2007 to 2008 Medicare claims using the International Classification of Diseases, Ninth Revision, Clinical Modification , diagnosis codes for claudication (N=8128), rest pain (N=3056), and ulceration/gangrene (N=11 770) and Current Procedural Terminology codes for endovascular revascularization (N=14 353) and open surgery (N=8601). Half (N=11 687) were identified as statin users before revascularization using Part D files. Amputations were identified using Current Procedural Terminology codes. Statin users compared with nonusers had lower amputation rates at 30 days (11.5% versus 14.4%; P <0.0001), 90 days (15.5% versus 19.3%; P <0.0001), and 1 year (20.9% versus 25.6%; P <0.0001). Survival analysis demonstrated improved limb salvage during 1 year for statin users compared with nonusers for the diagnosis of claudication ( P =0.003), a similar trend for rest pain ( P =0.061), and no improvement for ulceration/gangrene ( P =0.65).

Conclusions—

Preoperative statins were associated with improved 1-year limb salvage after lower extremity revascularization. The strongest association was found for patients with the diagnosis of claudication. Statins seem to be underused among Medicare patients with peripheral artery disease. Further evaluation of the use of preoperative statins and the potential benefits for peripheral vascular interventions is warranted.

Impact of critical limb ischemia on long-term cardiac mortality in diabetic patients undergoing percutaneous coronary revascularization

OBJECTIVE

Development of critical limb ischemia (CLI) has been reported as an independent predictor of cardiac mortality in diabetic patients. We aimed to determine whether CLI, managed in a structured setting of close collaboration between different vascular specialists and treated with early endovascular intervention, has any impact on long-term cardiac mortality of diabetic patients initially presenting with symptomatic coronary artery disease (CAD).

RESEARCH DESIGN AND METHODS

We designed a prospective observational study of 764 consecutive diabetic patients undergoing percutaneous coronary intervention (PCI) in whom development of CLI was assessed by a dedicated diabetic foot clinic. Cardiac mortality at 4-year follow-up was the primary end point of the study.

RESULTS

Among the 764 patients, 111 (14%) developed CLI (PCI-CLI group) and underwent revascularization of 145 limbs, with procedural success in 140 (96%). PCI-CLI patients at baseline had lower left ventricular ejection fraction (51 ± 11% vs. 53 ± 10%, P = 0.008), higher prevalence of dialysis (7% vs. 0.3%, P < 0.0001), and longer diabetes duration (13 ± 8 vs. 11 ± 7 years, P = 0.02) compared with PCI-only patients. At 4-year follow-up, cardiac mortality occurred in 10 (9%) PCI-CLI patients vs. 42 (6%) PCI-only patients (P = 0.2). Time-dependent Cox regression model for cardiac death revealed that CLI was not associated with an increased risk of cardiac mortality (hazard ratio 1.08 [95% CI 0.89-3.85]; P = 0.1).

CONCLUSIONS

The development of promptly assessed and aggressively treated CLI was not significantly associated with increased risk of long-term cardiac mortality in diabetic patients initially presenting with symptomatic CAD.

Haemodynamic optimisation in lower limb arterial surgery: room for improvement?

BACKGROUND

Goal-directed therapy has been proposed to improve outcome in high-risk surgery patients. The aim of this study was to investigate whether individualised goal-directed therapy targeting stroke volume and oxygen delivery could reduce the number of patients with post-operative complications and shorten hospital length of stay after open elective lower limb arterial surgery.

METHODS

Forty patients scheduled for open elective lower limb arterial surgery were prospectively randomised. The LiDCO™plus system was used for haemodynamic monitoring. In the intervention group, stroke volume index was optimised by administering 250 ml aliquots of colloid intraoperatively and during the first 6 h post-operatively. Following surgery, fluid optimisation was supplemented with dobutamine, if necessary, targeting an oxygen delivery index level ≥ 600 ml/min(/) m(2) in the intervention group. Central haemodynamic data were blinded in control patients. Patients were followed up after 30 days.

RESULTS

In the intervention group, stroke volume index, and cardiac index were higher throughout the treatment period (45 ± 10 vs. 41 ± 10 ml/m(2), P < 0.001, and 3.19 ± 0.73 vs. 2.77 ± 0.76 l/min(/) m(2), P < 0.001, respectively) as well as post-operative oxygen delivery index (527 ± 120 vs. 431 ± 130 ml/min(/) m(2), P < 0.001). In the same group, 5/20 patients had one or more complications vs. 11/20 in the control group (P = 0.05). After adjusting for pre-operative and intraoperative differences, the odds ratio for ≥ 1 complications was 0.18 (0.04-0.85) in the intervention group (P = 0.03). The median length of hospital stay did not differ between groups.

CONCLUSION

Perioperative individualised goal-directed therapy may reduce post-operative complications in open elective lower limb arterial surgery.

Factors predicting resource utilization and survival after major amputation

OBJECTIVE

Major amputation is associated with increased short-term healthcare resource utilization (RU), early mortality, and socioeconomic status (SES) disparities. Our objective is to study patient-specific and SES-related predictors of long-term RU and survival after amputation.

METHODS

This retrospective analysis identified 364 adult patients who underwent index major amputation for critical limb ischemia from January 1995 through December 2000 at two tertiary centers with outcomes through December 2010. Age, gender, SES (race, income, insurance, and marital status), comorbidities (congestive heart failure [CHF], diabetes, diabetes with complications, and renal failure [RF]), subsequent procedures, cumulative length of stay (cLOS), and mortality were analyzed. Bivariate and multivariate Poisson regression for subsequent procedures and cLOS and Cox proportional hazard modeling for all-cause mortality were undertaken.

RESULTS

During a mean follow-up of 3.25 years, amputation patients had mean cLOS of 71.2 days per person-year (median, 17.6), 19.5 readmissions per person-year (median, 2.1), 0.57 amputation-related procedures (median, 0), and 0.31 cardiovascular procedures (median, 0). Below-knee amputation as the index procedure was performed in 70% of patients, and 25% had additional amputation procedures. Of readmissions at ≤ 30 days, 52% were amputation-related. Overall mortality during follow-up was 86.9%; 37 patients (10.2%) died within 30 days. Among patients surviving >30 days, multivariate Poisson regression demonstrated that younger age (incidence rate ratio [IRR], 0.98), public insurance (IRR, 1.63), CHF (IRR, 1.60), and RF (IRR, 2.12) were associated with increased cLOS. Diabetes with complications (IRR, 1.90) and RF (IRR, 2.47) affected subsequent amputation procedures. CHF (IRR, 1.83) and RF (IRR, 3.67) were associated with a greater number of cardiovascular procedures. Cox proportional hazard modeling indicated older age (hazard ratio [HR], 1.04), CHF (HR, 2.26), and RF (HR, 2.60) were risk factors for decreased survival. Factors associated with SES were not significantly related to the outcomes.

CONCLUSIONS

This study found that RU is high for amputees, and increased RU persists beyond the perioperative period. Results were similar across SES indices, suggesting higher SES may not be protective against poor outcomes when limb salvage is no longer attainable. These findings support the hypothesis that SES disparities may be more modifiable during earlier stages of care for critical limb ischemia.

Influence of risk factors and comorbidities on the successful therapy and survival of patients with critical limb ischemia

BACKGROUND

Critical limb ischemia (CLI) is associated with an increased risk of limb amputation, low quality of life and cardiovascular death. The aim of this study is to identify the prognostic factors of mortality, revascularization failure and amputation failure, as part of risk factors for athero-sclerosis and comorbidities.

PATIENTS AND METHODS

We examined 198 patients operated for CLI. Cox analysis was performed to discern the factors that were associated with failure of initial surgical therapy and death.

RESULTS

For survival analysis, a significant model emerged with hypertension (p=0.00), cardiac comorbidities (p=0.00), renal comorbidities (p=0.04) and respiratory comorbidities (p=0.02) as significant predictors. Regarding the time to amputation failure, there was a significant model with insulin treated diabetes (p=0.00), coronary artery disease (p=0.02) and cerebrovascular disease (p=0.05) as significant predictors.

CONCLUSIONS

Significant predictors for mortality in CLI patients are high risk hypertension, severe coronary artery disease, renal failure requiring dialysis and chronic obstructive pulmonary disease. The association of these prognostic factors results in a proportional decrease of survival. The predictors for amputation failure were, in addition to local factors, insulin treated diabetes, coronary artery disease and cerebrovascular disease. The revascularization for limb salvage depends on the correct indication and accurate surgical technique.

Using risk models to improve patient selection for high-risk vascular surgery

Vascular surgeons frequently perform procedures aimed at limiting death, stroke, or amputation on patients who present with diseases such as aortic aneurysms, carotid atherosclerosis, and peripheral arterial occlusive disease. However, now more than ever surgeons must balance the potential benefits associated with these interventions with the risks of physiologic insult for these elderly patients, who often have significant comorbidity burdens and the potential for costly complications. In this paper, we highlight how regional and national datasets can help surgeons identify which patients are most likely to benefit from vascular operations and which patients are most likely to suffer complications in the postoperative period. By using these guidelines to improve patient selection, our risk models can help patients, physicians, and policymakers improve the clinical effectiveness of surgical and endovascular treatments for vascular disease.

Prediction of graft patency and mortality after distal revascularization and interval ligation for hemodialysis access-related hand ischemia

OBJECTIVE

The treatment goals of access-related hand ischemia (ARHI) are to reverse symptoms and salvage the access. Many procedures have been described, but the optimal treatment strategy remains unresolved. In an effort to guide clinical decision making, this study was undertaken to document our outcomes for distal revascularization and interval ligation (DRIL) and to identify predictors of bypass patency and patient mortality.

METHODS

A retrospective review was performed of all patients who underwent DRIL at the University of Florida from 2002 to 2011. Diagnosis of ARHI was based primarily upon clinical symptoms with noninvasive studies used to corroborate in equivocal cases. Patient demographics, procedure-outcome variables, and reinterventions were recorded. Bypass patency and mortality were estimated using cumulative incidence and Kaplan-Meier methodology, respectively. Cumulative incidence and Cox regression analysis were performed to determine predictors of bypass patency and mortality, respectively.

RESULTS

A total of 134 DRILs were performed in 126 patients (mean [standard deviation] age, 57 [12] years) following brachial artery-based access. The postoperative complication rate was 27% (19% wound), and 30-day mortality was 2%. The wrist-brachial index and digital brachial index increased 0.31 (0.25) and 0.25 (0.29), respectively. Symptoms resolved in 82% of patients, and 85% continued to use their access. Cumulative incidences (± standard error of the mean) of loss of primary and primary-assisted patency rates were 5% ± 2% and 4% ± 2% at 1 year and 22% ± 5% and 18% ± 5% at 5 years, respectively, with mean follow-up of 14.8 months. Univariate predictors of primary patency failure were DRIL complications (odds ratio [OR], 3.3; 95% confidence interval [CI], 1.2-8.9; P = .02), configuration other than brachiobasilic/brachiocephalic autogenous access (OR, 3.4; 95% CI, 1.4-8.3; P = .009), and two or more prior access attempts (OR, 4.1; 95% CI, 1.6-10.4; P = .004). Brachiocephalic access configuration (OR, 0.2; 95% CI, 0.04-0.8; P = .02) and autogenous vein conduit (OR, 0.2; 95% CI, 0.06-0.58; P = .004) were predictors of improved bypass patency. All-cause mortality was 28% and 79% at 1 and 5 years, respectively. Multivariable predictors of mortality were age >40 (hazard ratio [HR], 8.3; 95% CI, 2.5-33.3; P = .0004), grade 3 ischemia (HR, 2.6; 95% CI, 1.5-4.6; P = .0008), complication from DRIL (HR, 2.4; 95% CI, 1.3-4.5; P = .004), and smoking history (HR, 2.2; 95% CI, 1.3-4; P = .007). Patients with no prior access attempts had lower predicted mortality (HR, 0.5; 95% CI, 0.3-0.9; P = .02).

CONCLUSIONS

The DRIL procedure effectively improves distal perfusion and reverses the symptoms of ARHI while salvaging the access, but the long-term survival of these patients is poor. Given the poor survival, preoperative risk stratification is critical. Patients at high risk for DRIL failure and mortality may be best served with alternate remedial procedures.

APC resistance due to Factor V Leiden is not related to baseline inflammatory mediators or survival up to 10 years in patients with critical limb ischemia

To prospectively evaluate the potential influence of resistance to activated protein C (APC-resistance) on the initial inflammatory response, amputation rate and survival during 10 years of follow-up in patients with critical limb ischemia (CLI). Two hundred and fifty-six consecutive CLI patients were analyzed for APC-ratio, the Factor V Leiden mutation and inflammatory mediators and then prospectively followed for 10 years. Inflammatory mediators, amputation rate, morbidity and mortality were compared between patients with and without APC resistance. Of the 256 CLI patients, 35 (14 %) were heterozygotes and 2 (1 %) homozygotes for the Factor V gene mutation, whereas 219 (86 %) patients were non-APC resistant. No significant differences were found between APC resistant and non-APC resistant patients regarding inflammatory mediators. Non-APC resistant patients more often had infrainguinal atherosclerosis (172 [79 %] vs 22 [59 %]; p = 0.017). Amputation rate at 1 year did not differ. Furthermore, there were no significant differences between groups regarding 1-, 3-, 5-, or 10-year survival. APC resistance in patients with CLI was not related to inflammatory activity, and had no impact on limb salvage or rate of amputation or long-term mortality. APC-resistant CLI-patients less frequently had infrainguinal arteriosclerosis, however.

Critical limb ischemia: advanced medical therapy

Systemic atherosclerosis and its risk factors are present in the majority of patients with critical limb ischemia. Aggressive medical therapy is an immediate and necessary part of the work-up and management of these patients and will involve a multidisciplinary approach. Risk stratification based on a patient's current clinical cardiovascular condition is important in determining the most appropriate and safe intervention and will allow both the patient and physician to make an informed decision regarding risk- and cost-benefits of treatment.