Critical limb ischemia

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers are Associated with Improved Amputation Free Survival in Chronic Limb-Threatening Ischemia

BACKGROUND

In the Heart Outcomes Prevention Evaluation (HOPE) study, investigators found that ramipril was associated with improved survival as well as decreased MI and stroke rates in patients with peripheral arterial disease. Nonetheless, their effect on chronic limb-threatening ischemia (CLTI)-specific outcomes is unclear. We aim to assess the effect of ACEIs/ARBs on amputation-free survival in CLTI patients undergoing peripheral vascular intervention (PVI) in a Medicare-linked database.

METHODS

Patients undergoing PVI in the VQI-VISION database were included. Primary outcome included amputation-free survival. Kaplan Meier survival and multivariable Cox regression analyses were used to assess one-year outcomes.

RESULTS

A total of 34,284 patients were included, and 46.3% of whom were discharged on ACEIs/ARBs. Patients discharged on ACEIs/ARBs were more likely to be smokers, diabetics, and hypertensive. They were also more likely to present with rest pain. The overall one-year survival for patients on ACEIs/ARBs vs those who are not was (79.1% vs 69.4%, P<0.001). Freedom from amputation was 87.8% for patients on ACEIs/ARBs vs 84.2% for those who were not (P<0.001). Amputation-free survival was 70.5% vs 59.5% for ACEIs/ARBs vs no ACEIs/ARBs (P<0.001). After adjusting for potential confounders, ACEIs/ARBs use was associated with lower one-year mortality (HR: 0.77, 95%CI (0.7-0.8), P<0.001), amputation (HR: 0.89, 95%CI (0.8-0.9), P<0.001), and amputation or death (HR: 0.79, 95%CI (0.76-0.8), P<0.001).

CONCLUSIONS

ACEIs/ARBs were independently associated with lower amputation, improved survival, and amputation-free survival at one year in CLTI patients undergoing PVI. The fact that more than half the patients were not discharged on these medications presents an area for potential quality improvement.

Comparison between intermittent claudication versus chronic limb-threatening ischemia in peripheral arterial disease: a retrospective multicenter cohort study

Purpose

The anatomical distribution, characteristics of lesions, and treatment modalities for peripheral artery disease (PAD) are diverse. Endovascular intervention is popular for symptomatic PAD, for both intermittent claudication (IC) and chronic limb-threatening ischemia (CLTI). We aimed to investigate the endovascular devices used by comparing patients with PAD referred for endovascular revascularization with IC and CLTI.

Methods

We identified 736 patients with PAD enrolled in the multicenter PAD registry in South Korea from 2019 to 2022. Of these patients, 636 received endovascular treatment at the time of this study. After excluding missing data, we analyzed 506 patients with IC or CLTI. Patients' characteristics, target lesions, and endovascular device data such as type, length, balloon diameter, and stent, were examined. Procedure outcomes of the aortoiliac, femoropopliteal, and below-the-knee lesions were analyzed.

Results

Patients with CLTI were more likely to have diabetes mellitus, below-the-knee interventions, and multilevel PAD than the IC group. Patients with IC had more aortoiliac artery lesions and underwent atherectomies than the CLTI group (63.3% and 61.1% vs. 39.7% and 40.6%, respectively; P < 0.001). In patients with femoropopliteal lesions, those with CLTI were more revascularized with stents than the patients with IC, without significant differences (35.3% vs. 29.1%, P = 0.161). Compared to the IC group, the CLTI patients showed significantly worse rates of primary patency, amputation, and mortality (P = 0.029, P < 0.001, and P < 0.001, respectively).

Conclusion

Among Korean patients with PAD, there is a significant difference in baseline and lesion characteristics, endovascular strategies, and short-term follow-up outcomes among those with IC and CLTI.

Histological Changes in the Popliteal Artery Wall in Patients with Critical Limb Ischemia

INTRODUCTION

This prospective study aims to illustrate the histopathological arterial changes in the popliteal artery in peripheral arterial disease of the lower limbs.

MATERIAL AND METHOD

A total of 60 popliteal artery segments taken from patients who had undergone lower limb amputation were examined between April and June 2023. The degree of arterial stenosis, medial calcinosis, and the vasa vasorum changes in the arterial adventitia were quantified. The presence of risk factors for atherosclerosis was also observed.

RESULTS

Atherosclerotic plaque was found in all of the examined segments. Medial calcinosis was observed in 40 (66.6%) of the arterial segments. A positive association between the degree of arterial stenosis and the vasa vasorum changes in the arterial adventitia was also found (p = 0.025). The level of blood sugar and cholesterol were predictive factors for the severity of atherosclerosis.

CONCLUSIONS

Atherosclerosis and medial calcinosis are significant in patients who underwent lower limb amputation. Medial calcinosis causes damage to the arterial wall and leads to a reduction in responsiveness to dilator stimuli.

Bioengineering Cell Therapy for Treatment of Peripheral Artery Disease

Peripheral artery disease is an atherosclerotic disease associated with limb ischemia that necessitates limb amputation in severe cases. Cell therapies comprised of adult mononuclear or stromal cells have been clinically tested and show moderate benefits. Bioengineering strategies can be applied to modify cell behavior and function in a controllable fashion. Using mechanically tunable or spatially controllable biomaterials, we highlight examples in which biomaterials can increase the survival and function of the transplanted cells to improve their revascularization efficacy in preclinical models. Biomaterials can be used in conjunction with soluble factors or genetic approaches to further modulate the behavior of transplanted cells and the locally implanted tissue environment in vivo. We critically assess the advances in bioengineering strategies such as 3-dimensional bioprinting and immunomodulatory biomaterials that can be applied to the treatment of peripheral artery disease and then discuss the current challenges and future directions in the implementation of bioengineering strategies.

Hypertension Management in Peripheral Artery Disease: A Mini Review

Lower extremity peripheral artery disease (PAD) affects over 230 million adults globally, with hypertension being one of the major risk factors for the development of PAD. Despite the high prevalence, patients with hypertension who have concomitant PAD are less likely to receive adequate therapy. Through this review, we present the current evidence underlying hypertension management in PAD, guideline-directed therapies, and areas pending further investigation. Multiple studies have shown that both high and relatively lower blood pressure levels are associated with worse health outcomes, including increased morbidity and mortality. Hence, guideline-directed recommendation involves cautious management of hypertensive patients with PAD while ensuring hypotension does not occur. Although any antihypertensive medication can be used to treat these patients, the 2017 American Heart Association/American College of Cardiology (AHA/ACC), 2017 European Society of Cardiology (ESC), and 2022 Canadian guidelines favor the use of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) as the initial choice. Importantly, data on blood pressure targets and treatment of hypertension in PAD are limited and largely stem from sub-group studies and post-hoc analysis. Large randomized trials in patients with PAD are required in the future to delineate hypertension management in this complex patient population.

The CathCam: A Novel Angioscopic Solution for Endovascular Interventions

Peripheral arterial diseases are commonly managed with endovascular procedures, which often face limitations in device control and visualization under X-ray fluoroscopy guidance. In response, we developed the CathCam, an angioscope integrated into an expandable cable-driven parallel mechanism to enhance real-time visualization, precise device positioning and catheter support for successful plaque crossing. The primary objective of this study was to assess and compare the performance of the novel CathCam with respect to conventional catheters and the CathPilot (i.e., CathCam without the angioscope), for applications in crossing chronic total occlusions (CTO). We first assessed the system in 3D-printed phantom models, followed by an ex vivo evaluation with CTO samples from a patient's superficial femoral artery. We measured and compared success rates, crossing times, and fluoroscopy times in both experiments. The CathCam demonstrated a 100% success rate in phantom experiments and a 75% success rate in ex vivo experiments with CTO samples, compared to conventional catheters, with 35% and 25% success rates, respectively. The average crossing times for the CathCam and the conventional catheter were 31 s and 502 s for the phantom experiments and 210 s and 511 s for the actual CTO lesions. The Cathcam also showed to be a reliable endovascular imaging approach in an in vivo experiment. Compared to conventional catheters, the CathCam significantly increased the success rate and reduced crossing and fluoroscopy times in both phantom and ex vivo setups. CathCam can potentially improve clinical outcomes for minimally invasive endovascular interventions by offering high-resolution real-time imaging alongside accurate device control.

Effects of iloprost in patients with critical limb ischemia: Results of a cohort study from the COPART registry

BACKGROUND

Iloprost has been proposed as an alternative to amputation in Critical Limb Ischemia (CLI) patients when revascularization was unsuccessful or not possible. Nonetheless, there is limited evidence of its benefit. The main objective was to evaluate the effectiveness of iloprost and the secondary objective was to evaluate its safety.

METHODS

In this cohort study including CLI patients from the COPART registry from 2006/10 to 2021/01, patients exposed to iloprost were matched with up to three unexposed patients according to age, sex, and Propensity Score (PS) for exposure to iloprost. The main outcome combined the occurrence of all-cause death and major amputations; survival was assessed over one-year using Kaplan-Meier estimates and Cox model analyses. Major Adverse Cardiovascular Events (MACE) were chosen as the safety outcome; the association with iloprost was estimated using a logistic regression model.

RESULTS

Among 1850 CLI patients, 201 were exposed to iloprost (71.6% men; median age: 72 years vs. 72.1%; 75 years for unexposed). In 134 exposed patients matched to 375 unexposed patients, 14 major amputations and 24 deaths occurred in exposed patients (28.4%) vs. 33 and 46 respectively in the unexposed patients (20.9%). The hazard ratio (HR) was of 1.49 (95% Confidence Interval: 1.01-2.20). The association remained in the subgroup of "no option" patients (HR: 1.74; [1.01-2.20]). Regarding safety, 21/201 (10.7%) exposed patients experienced MACE vs. 146/1649 (9.41%) unexposed patients (unadjusted Odds Ratio [OR]: 1.17 [0.72-1.90]; adjusted OR: 1.23 [0.72-2.11]).

CONCLUSION

The study did not find any benefit of iloprost in CLI patients and even suggested a deleterious effect.

Gender Differences and Amputation Risk in Peripheral Artery Disease-A Single-Center Experience

Background and Objectives: Peripheral artery disease (PAD) affects both genders, but the knowledge of clinical and therapeutic aspects particular to each gender has a prognostic value, modulating the risk of amputation and helping to reduce the risk of death or the occurrence of an acute vascular event secondary to optimal management. Materials and Methods: We conducted a retrospective, descriptive study that included 652 patients with PAD who were evaluated at "St. Spiridon" Hospital's Cardiology Department and divided into two groups according to gender: women (100 cases) and men (552 cases). We evaluated demographics, anthropometric data, as well as clinical and paraclinical parameters in the two groups. Results: Men had a lower mean age (p < 0.001), higher mean BMI (p = 0.049) and were more frequent smokers. (p = 0.008). Hypercholesterolemia (p = 0.026), obesity (p = 0.009), concomitant cerebrovascular (p = 0.005) and chronic kidney disease (p = 0.046) were more common in women, while coronary artery disease (p = 0.033) was more common in men. The number of angiographic stenotic lesions (p = 0.037) is a statistically significant parameter in our study, with both genders predominantly associated with stenotic lesions. In addition, directly proportional relationships were found between smoking, uric acid, inflammatory markers, and the number of stenotic lesions and thromboses or the ankle-brachial index (ABI). In the subgroup of men, the number of stenotic and thrombosed lesions positively correlated with the ABI value (p < 0.001). The presence of more than three cardiovascular risk factors (p = 0.001) and serum triglyceride levels (p = 0.019) significantly correlated with the number of angiographically detected lesions. We applied several risk scores (PREVENT III, Finnvasc Score, or GermanVasc risk score) in our study group for prognostic purposes, without showing statistically significant differences between genders. Men, rest pain, gangrene, smoking status, the presence of more than three cardiovascular risk factors, or a serum HDL-cholesterol level below 40 mg/dL (p < 0.001 for all parameters) are independent predictors associated with amputation in our study group. Conclusions: In our study, we demonstrated that several clinical-paraclinical particularities guide the diagnosis, providing the clinician with prognostic and therapeutic tools to choose the optimal management with maximum benefits.

Synergistic Therapeutic Potential of Dual 3D Mesenchymal Stem Cell Therapy in an Ischemic Hind Limb Mouse Model

Three-dimensional (3D) culture systems have been widely used to promote the viability and metabolic activity of mesenchymal stem cells (MSCs). The aim of this study was to explore the synergistic benefits of using dual 3D MSC culture systems to promote vascular regeneration and enhance therapeutic potential. We used various experimental assays, including dual 3D cultures of human adipose MSCs (hASCs), quantitative reverse transcription polymerase chain reaction (qRT-PCR), in vitro cell migration, Matrigel tube network formation, Matrigel plug assay, therapeutic assays using an ischemic hind limb mouse model, and immunohistochemical analysis. Our qRT-PCR results revealed that fibroblast growth factor 2 (FGF-2), granulocyte chemotactic protein-2 (GCP-2), and vascular endothelial growth factor-A (VEGF-A) were highly upregulated in conventional 3D-cultured hASCs (ASC-3D) than in two-dimensional (2D)-cultured hASCs. Hepatocyte growth factor (HGF), insulin-like growth factor-1 (IGF-1), and stromal-cell-derived factor-1 (SDF-1) showed higher expression levels in cytokine-cocktail-based, 3D-cultured hASCs (ASC-3Dc). A conditioned medium (CM) mixture of dual 3D ASCs (D-3D; ASC-3D + ASC-3Dc) resulted in higher migration and Matrigel tube formation than the CM of single 3D ASCs (S-3D; ASC-3D). Matrigel plugs containing D-3D contained more red blood cells than those containing S-3D. D-3D transplantation into ischemic mouse hind limbs prevented limb loss and augmented blood perfusion when compared to S-3D transplantation. Transplanted D-3D also revealed a high capillary density and angiogenic cytokine levels and transdifferentiated into endothelial-like cells in the hind limb muscle. These findings highlight the benefits of using the dual 3D culture system to optimize stem-cell-based therapeutic strategies, thereby advancing the therapeutic strategy for ischemic vascular disease and tissue regeneration.

Therapeutic application of regeneration-associated cells: a novel source of regenerative medicine

Chronic diseases with comorbidities or associated risk factors may impair the function of regenerative cells and the regenerative microenvironment. Following this consideration, the vasculogenic conditioning culture (VCC) method was developed to boost the regenerative microenvironment to achieve regeneration-associated cells (RACs), which contain vasculogenic endothelial progenitor cells (EPCs) and anti-inflammatory/anti-immunity cells. Preclinical and clinical studies demonstrate that RAC transplantation is a safe and convenient cell population for promoting ischemic tissue recovery based on its strong vasculogenicity and functionality. The outputs of the scientific reports reviewed in the present study shed light on the fact that RAC transplantation is efficient in curing various diseases. Here, we compactly highlight the universal features of RACs and the latest progress in their translation toward clinics.

Integration of palliative care consultation into the management of patients with chronic limb-threatening ischemia

OBJECTIVE

We assessed the feasibility of integrating palliative care consultation into the routine management of patients with chronic limb-threatening ischemia (CLTI). Additionally, we sought to describe patient-reported outcomes from the palliative care and vascular literature in patients with CLTI receiving a palliative care consultation at our institution.

METHODS

This was a single-institution, prospective, observational study that aimed to assess feasibility of incorporating palliative care consultation into the management of patients admitted to our tertiary academic medical center with CLTI by looking at utilization of palliative care before and after implementation of a protocol-based palliative care referral system. A survey comprised of patient-reported outcomes from the palliative care literature was administered to patients before and after palliative consultation. Length of stay and mortality were compared between our study cohort and a historic cohort of patients admitted with CLTI.

RESULTS

Over a 14-month enrollment period, 44% of patients (n = 39) with CLTI (rest pain, 36%; tissue loss, 64%) admitted to the vascular service received palliative care consultation, compared with 5% of patients (n = 4) who would have met criteria over the preceding 14 months before our protocol was instituted. The mean age was 69 years, 23% were female, 92% were white, and 49% were able to ambulate independently. Revascularization included bypass (46%), peripheral vascular intervention (23%), and femoral endarterectomy (21%). Additional procedures included minor amputation or wound debridement (26%) and major amputation (15%). No patients received medical management alone. After receiving palliative care consultation, patients reported experiencing less emotional distress than before consultation (P = .03). They also reported being less bothered by uncertainty regarding what to expect from the course of their illness (P = .002). Fewer patients reported being unsure of the purpose of their medical care after palliative care consultation (8%) vs before (18%), although this was not statistically significant (P = .10). Median length of stay was longer in the study group compared with the historic cohort (8 vs 7 days; P = .02). There was no difference in 30-day mortality (3% vs 8%; P = .42) between the study group and the historic cohort (n = 77).

CONCLUSIONS

Integrating inpatient palliative care consultation into the routine management of patients with CLTI is feasible and may improve emotional domains of health-related quality of life. This study laid the foundation for future studies on longer term outcomes of patients with CLTI undergoing palliative care consultation as well as the benefit of outpatient palliative care consultation in patients with CLTI.

Robust critical limb ischemia porcine model involving skeletal muscle necrosis

This work sought to develop a robust and clinically relevant swine model of critical limb ischemia (CLI) involving the onset of ischemic muscle necrosis. CLI carries about 25-40% risk of major amputation with 20% annual mortality. Currently, there is no specific treatment that targets the ischemic myopathy characteristic of CLI. Current swine models of CLI, with tolerable side-effects, fail to achieve sustained ischemia followed by a necrotic myopathic endpoint. Such limitation in experimental model hinders development of effective interventions. CLI was induced unilaterally by ligation-excision of one inch of the common femoral artery (CFA) via infra-inguinal minimal incision in female Yorkshire pigs (n = 5). X-ray arteriography was done pre- and post-CFA transection to validate successful induction of severe ischemia. Weekly assessment of the sequalae of ischemia on limb perfusion, and degree of ischemic myopathy was conducted for 1 month using X-ray arteriography, laser speckle imaging, CTA angiography, femoral artery duplex, high resolution ultrasound and histopathological analysis. The non-invasive tissue analysis of the elastography images showed specific and characteristic pattern of increased muscle stiffness indicative of the fibrotic and necrotic outcome expected with associated total muscle ischemia. The prominent onset of skeletal muscle necrosis was evident upon direct inspection of the affected tissues. Ischemic myopathic changes associated with inflammatory infiltrates and deficient blood vessels were objectively validated. A translational model of severe hindlimb ischemia causing ischemic myopathy was successfully established adopting an approach that enables long-term survival studies in compliance with regulatory requirements pertaining to animal welfare.

Systemic arterial calcium burden in patients with chronic limb-threatening ischemia

INTRODUCTION

5-year mortality of chronic limb-threatening ischemia (CLTI) is 50-60% and coronary artery disease (CAD) is the main cause of death of CLTI patients, followed by stroke. The aim of this study is to quantify and qualify the calcium load in different arterial territories in patients with CLTI.

METHODS

Prospectively, 60 patients with CLTI were included and received a full-body CT scan. 6 patients were excluded. Different arterial territories (the peripheral lower extremity arteries, coronary arteries, extracranial and intracranial carotid arteries, thoracic and abdominal aorta) were analyzed. Analysis and interrelations of both quantitative and semi-quantitative CT measurements was performed.

RESULTS

Mean age was 72 years (range 47-95; SD 11.4). Almost all CLTI patients had calcified arterial beds (femoropopliteal 100%, crural 98.1%, coronary 100%, carotid bifurcation 96.2%, internal carotid artery 98.1%, thoracic aorta 96.2%, abdominal aorta 92.3%). Nearly all arterial territories had severe calcifications. 57% had a very high coronary Agatston score (>1000), and 35% extremely high (>2000). Calcifications in the lower extremity were significantly correlated to CAC score, carotid artery bifurcation calcification score, and to a lesser extent correlated to annular calcifications in the aorta. Very high and extremely high total CAC scores were strongly correlated with severe lower extremity arterial calcifications and severe carotid and intracranial internal carotid artery, thoracic and abdominal aorta calcifications in patients with CLTI patients.

CONCLUSIONS

In CLTI patients nearly all arterial territories are severely calcified, suggesting that systemic calcification plays an important role in the poor outcome of this disease.

Application of machine learning algorithms in electronic medical records to predict amputation-free survival after first revascularization in patients with peripheral artery disease

BACKGROUND

This study aimed to apply eight machine learning algorithms to develop the optimal model to predict amputation-free survival (AFS) after first revascularization in patients with peripheral artery disease (PAD).

METHODS

Among 2130 patients from 2011 to 2020, 1260 patients who underwent revascularization were randomly assigned to training set and validation set in an 8:2 ratio. 67 clinical parameters were analyzed by lasso regression analysis. Logistic regression, gradient boosting machine, random forest, decision tree, eXtreme gradient boosting, neural network, Cox regression, and random survival forest (RSF) were applied to develop prediction models. The optimal model was compared with GermanVasc score in testing set comprising patients from 2010.

RESULTS

The postoperative 1/3/5-year AFS were 90%, 79.4%, and 74.1%. Age (HR:1.035, 95%CI: 1.015-1.056), atrial fibrillation (HR:2.257, 95%CI: 1.193-4.271), cardiac ejection fraction (HR:0.064, 95%CI: 0.009-0.413), Rutherford grade ≥ 5 (HR:1.899, 95%CI: 1.296-2.782), creatinine (HR:1.03, 95%CI: 1.02-1.04), surgery duration (HR:1.03, 95%CI: 1.01-1.05), and fibrinogen (HR:1.292, 95%CI: 1.098-1.521) were independent risk factors. The optimal model was developed by RSF algorithm, with 1/3/5-year AUCs in training set of 0.866 (95% CI:0.819-0.912), 0.854 (95% CI:0.811-0.896), 0.844 (95% CI:0.793-0.894), in validation set of 0.741 (95% CI:0.580-0.902), 0.768 (95% CI:0.654-0.882), 0.836 (95% CI:0.719-0.953), and in testing set of 0.821 (95%CI: 0.711-0.931), 0.802 (95%CI: 0.684-0.919), 0.798 (95%CI: 0.657-0.939). The c-index of the model outperformed GermanVasc Score (0.788 vs 0.730). A dynamic nomogram was published on shinyapp (https://wyy2023.shinyapps.io/amputation/).

CONCLUSION

The optimal prediction model for AFS after first revascularization in patients with PAD was developed by RSF algorithm, which exhibited outstanding prediction performance.

The Relationship Between Peripheral Arterial Disease Severity and Socioeconomic Status

BACKGROUND

Although socioeconomic disparities in outcomes of peripheral artery disease (PAD) have been well studied, little is known about relationship between severity of PAD and socioeconomic status. The objective of this study was to examine this relationship.

METHODS

Patients who had operations for severe PAD (rest pain or tissue loss) were identified in the National Inpatient Sample, 2005-2014. They were stratified by the median household income (MHI) quartiles of their residential ZIP codes. Other characteristics such as race/ethnicity and insurance type were extracted. Factors associated with more severe disease (tissue loss) were evaluated using multivariable regression analyses.

RESULTS

There were 765,175 patients identified; 34% in the first MHI quartile and 18% in the fourth MHI quartile. Compared to patients in the first quartile, those in the fourth quartile were more likely White (69% vs. 42%, P < 0.001), more likely ≥65 years old (75% vs. 62%, P < 0.001), and were less likely to undergo amputations (25% vs. 34%, P < 0.001). After adjusting for patient characteristics, the fourth quartile was associated with more severe disease [Odds ratio: 1.19, 95% confidence interval (CI): 1.11-1.27] compared to the first quartile.

CONCLUSIONS

While higher MHI was associated with higher PAD severity, patients with high MHI were less likely to undergo amputations indicating a disparity in the choice of treatment for PAD. Increased efforts are necessary to reduce socioeconomic disparities in the treatment of severe PAD.

The impact of diabetic nephropathy and severe diabetic retinopathy on chronic limb threatening ischemia risk in individuals with type 1 diabetes: a nationwide, population study

Background

The prevalence, incidence and risk factors and especially the effect of diabetic nephropathy (DN) and diabetic retinopathy on the risk of chronic limb threatening ischemia (CLTI) have been sparsely studied in individuals with type 1 diabetes (T1D).

Methods

The prospective cohort study consisted of 4697 individuals with T1D from the nationwide Finnish Diabetic Nephropathy (FinnDiane) Study. Medical records were thoroughly reviewed in order to ascertain all CLTI events. The key risk factors were DN and severe diabetic retinopathy (SDR).

Findings

There were 319 events of confirmed CLTI, 102 prevalent events at baseline and 217 incident events during the follow-up of 11.9 (IQR 9.3-13.8) years. The 12-year cumulative incidence of CLTI was 4.6% (95% CI 4.0-5.3). Risk factors included presence of DN, SDR, age, duration of diabetes, HbA_1c, systolic blood pressure, triglycerides and current smoking. Sub-hazard ratios (SHRs) according to combinations of DN status and presence (+) or absence (-) of SDR were 4.8 (2.0-11.7) for normoalbuminuria/SDR+, 3.2 (1.1-9.4) for microalbuminuria/SDR-, 11.9 (5.4-26.5) for microalbuminuria/SDR+, 8.7 (3.2-23.2) for macroalbuminuria/SDR-, 15.6 (7.4-33.0) for macroalbuminuria/SDR+ and 37.9 (17.2-78.9) for kidney failure compared with individuals with normal albumin excretion rate and without SDR.

Interpretation

Diabetic nephropathy, especially kidney failure, is associated with high risk of limb threatening ischemia in individuals with T1D. The risk of CLTI increases gradually according to the severity of diabetic nephropathy. Also, diabetic retinopathy is independently and additively associated with high risk of CLTI.

Funding

This research was funded by grants from Folkhälsan Research Foundation, Academy of Finland (316664), Wilhelm and Else Stockmann Foundation, Liv och Hälsa Society, Novo Nordisk Foundation (NNF OC0013659), Finnish Foundation for Cardiovascular Research, Finnish Diabetes Research Foundation, Medical Society of Finland, Sigrid Jusélius Foundation and Helsinki University Hospital Research Funds.

An Overview of the Treatment Strategies of Extremities Ischemia in the Intensive Care Unit

OBJECTIVES

 To investigate the effect of the peripheral block on peripheral ischemia on the extremities of patients in the intensive care unit (ICU).

MATERIALS AND METHODS

Sixty-two patients with ischemic peripheral vascular disease were divided retrospectively into two groups; Group 1 (patients who underwent USG-guided infraclavicular or femoral block, n=20) and Group 2 (patients who did not experience any block, n=42). The demographic characteristics of the patients, the diagnosis of hospitalization, the day when the circulatory disorder developed, laboratory tests at the time of diagnosis, other medical treatments applied, presence of inotropic support, the response of ischemia on extremities, amputation, duration of hospital stay, discharge and mortality were compared.

RESULTS

The most common reason for hospitalization was cerebrovascular disease. There was no statistical difference between the groups regarding age, gender, height, body weight, and diagnosis. There was no statistical difference between the groups regarding hematocrit, lactate, creatinine, and albumin values, the day when the peripheral ischemia developed in extremities, inotropic and prednisolone use, presence of cannulation, length of hospital stays, and mortality. The number of patients discharged from the intensive care unit in Group 1 was significantly higher than in Group 2 (p=0.048). Amputation was performed on one patient in Group 1 and two patients in Group 2. There was a decrease in peripheral ischemia in 14 (70%) of the patients in Group 1 and 25 (59.5%) of the patients in Group 2.

CONCLUSIONS

Targeted peripheral block techniques for peripheral circulatory disorders for selected ICU patients in conjunction with preventive and medical treatments may decrease peripheral ischemia in extremities and increase ICU discharge.

Safety of paclitaxel-coated devices in the femoropopliteal arteries: A systematic review and meta-analysis

Background

Clinical benefit of paclitaxel-coated devices for patients with peripheral arterial disease has been confirmed in randomized controlled trials (RCTs). A meta-analysis published in 2018 identified late mortality risk over a long follow-up period due to use of paclitaxel-coated devices in the femoropopliteal arteries, which caused enormous controversy and debates globally. This study aims to further evaluate the safety of paclitaxel-coated devices by incorporating the most recently published data.

Methods

We searched for candidate studies in PubMed (MEDLINE), Scopus, EMBASE (Ovid) online databases, government web archives and international cardiovascular conferences. Safety endpoints of interest included all-cause mortality rates at one, two and five years and the risk ratio (RR) was used as the summary measure. The primary analysis was performed using random-effects models to account for potential clinical heterogeneity.

Findings

Thirty-nine RCTs including 9164 patients were identified. At one year, the random-effects model yielded a pooled RR of 1.06 (95% CI [0.87, 1.29]) indicating no difference in short-term all-cause deaths between the paclitaxel and control groups (crude mortality, 4.3%, 214/5025 versus 4.5%, 177/3965). Two-year mortality was reported in 26 RCTs with 382 deaths out of 3788 patients (10.1%) in the paclitaxel arm and 299 out of 2955 patients (10.1%) in the control arm and no association was found between increased risk of death and usage of paclitaxel-coated devices (RR 1.08, 95% CI [0.93, 1.25]). Eight RCTs recorded all-cause deaths up to five years and a pooled RR of 1.18 (95% CI [0.92, 1.51]) demonstrated no late mortality risk due to use of paclitaxel-coated devices (crude mortality, paclitaxel 18.2%, 247/1360 versus control 15.2%, 122/805).

Conclusions

We found no significant difference in either short- or long-term all-cause mortalities between patients receiving paclitaxel-coated and uncoated devices. Further research on the longer-term safety of paclitaxel usage (e.g., 8- or 10-year) is warranted.

Registration

PROSPERO, CRD42021246291.

Predictors of Amputation-free Survival after Endovascular Intervention for Chronic Limb-Threatening Ischemia in the Modern era

BACKGROUND

Chronic limb-threatening (CLTI) is associated with 25% limb loss and 25% mortality at 1-year. Its lethality increases to 45% in patients subjected to a major amputation. Percutaneous peripheral intervention (PPI) constitutes an attractive and less morbid treatment option for patients with CLTI. The purpose of this study was to assess amputation-free survival (AFS) in a contemporary cohort treated with endovascular recanalization and assess its predictors.

METHODS

Patients with CLTI undergoing endovascular revascularization at a single regional hospital between 2015-2019 were reviewed. Baseline demographic characteristics, Wound, Ischemia, and foot Infection (WIfI) stage, technical details, and clinical outcomes were tabulated. The primary endpoint was AFS; a P-value < 0.05 was used for univariate screening and inclusion in a multivariable model.

RESULTS

A total of 137 limbs in 111 patients were studied. Comorbidities were prevalent and included diabetes (65%), congestive heart failure (21%), and dialysis dependence (18%). The majority of revascularized limbs presented with advanced wounds (66% WIfI stages 3-4; 47% Rutherford category 6). Presenting WIfI stages were similar across races (P = 0.26). Peripheral interventions most commonly targeted femoropopliteal disease (69%), although 26% were multilevel. Percutaneous atherectomy, stenting, and paclitaxel-coated or eluting devices were utilized in 68%, 28%, and 15% of cases, respectively. After a median follow-up of 16 months (interquartile range IQR = 4-29 months), significant independent predictors of reduced AFS included nonWhite race (HR = 2.96 [1.42-6.17]; P = 0.004) and WIfI stage 4 wounds (HR = 2.23 [1.10-4.52]; P = 0.026). At one year following successful revascularization, only 59% ± 1% of patients were alive with their limb intact.

CONCLUSIONS

Despite considerable and consistent advances in urban health care delivery and the techniques of PPI, CLTI remains a morbid and deadly disease. Even in the endovascular era, nearly half of all patients presenting with CLTI will lose their limb and/or life within the first year. Unfortunately, late-stage presentation continues to be commonplace. Although endovascular intervention can reliably restore patency to affected arteries, this appears insufficient to restore most patients to health.

Peripheral arterial disease and hypertension

PURPOSE OF REVIEW

Hypertension (HTN) is a well known risk factor for atherosclerosis and peripheral arterial disease (PAD). PAD affects more than 250 million people globally and is associated with worse clinical outcomes. Although multiple studies have been performed to evaluate treatment of HTN in patients with PAD, blood pressure management in this high-risk cohort remains poor.

RECENT FINDINGS

There has been conflicting evidence regarding blood pressure goals in PAD with some recent studies showing adverse outcomes with low blood pressure in this patient population. Current guidelines, however, continue to recommend treatment goals in PAD patients similar to patients without PAD. To date, no single antihypertensive drug class has shown a clear benefit in PAD population over other antihypertensive drug classes.

SUMMARY

Prospective randomized trials enrolling PAD patients are required that can shed light on optimum blood pressure target and also distinguish between different antihypertensive drugs in terms of reducing adverse outcomes.

Off-the-Shelf, Heparinized Small Diameter Vascular Graft Limits Acute Thrombogenicity in a Porcine Model

Thrombogenicity poses a challenge to the clinical translation of engineered grafts. Previously, small-diameter vascular grafts (sdVG) composed of fibrin hydrogel microfiber tubes (FMT) with an external poly(ε-caprolactone) (PCL) sheath supported long-term patency in mice. Towards the development of an sdVG with off-the-shelf availability, the FMT's shelf stability, scale-up, and successful conjugation of an antithrombotic drug to the fibrin scaffold are reported here. FMTs maintain mechanical stability and high-water retention after storage for one year in a freezer, in a refrigerator, or at room temperature. Low molecular weight heparin-conjugated fibrin scaffolds enabled local and sustained delivery during two weeks of enzymatic degradation. Upscaled fabrication of sdVGs provides natural biodegradable grafts with size and mechanics suitable for human application. Implantation in a carotid artery interposition porcine model exhibited no rupture with thrombi prevented in all heparinized sdVGs (n=4) over 4-5 weeks. Remodeling of the sdVGs is demonstrated with endothelial cells on the luminal surface and initial formation of the medial layer by 4-5 weeks. However, neointimal hyperplasia at 4-5 weeks led to the stenosis and occlusion of most of the sdVGs, which must be resolved for future long-term in vivo assessments. The off-the-shelf, biodegradable heparinized fibrin sdVG layer limits acute thrombogenicity while mediating extensive neotissue formation as the PCL sheath maintains structural integrity. STATEMENT OF SIGNIFICANCE: : To achieve clinical and commercial utility of small-diameter vascular grafts as arterial conduits, these devices must have off-the-shelf availability for emergency arterial bypass applications and be scaled to a size suitable for human applications. A serious impediment to clinical translation is thrombogenicity. Treatments have focused on long-term systemic drug therapy, which increases the patient's risk of bleeding complications, or coating grafts and stents with anti-coagulants, which minimally improves patient outcomes even when combined with dual anti-platelet therapy. We systematically modified the biomaterial properties to develop anticoagulant embedded, biodegradable grafts that maintain off-the-shelf availability, provide mechanical stability, and prevent clot formation through local drug delivery.

Differences in Comorbidities Explain Black-White Disparities in Outcomes After Femoropopliteal Endovascular Intervention

BACKGROUND

Black adults have a higher incidence of peripheral artery disease and limb amputations than White adults in the United States. Given that peripheral endovascular intervention (PVI) is now the primary revascularization strategy for peripheral artery disease, it is important to understand whether racial differences exist in PVI incidence and outcomes.

METHODS

Data from fee-for-service Medicare beneficiaries ≥66 years of age from 2016 to 2018 were evaluated to determine age- and sex-standardized population-level incidences of femoropopliteal PVI among Black and White adults over the 3-year study period. Patients' first inpatient or outpatient PVIs were identified through claims codes. Age- and sex-standardized risks of the composite outcome of death and major amputation within 1 year of PVI were examined by race.

RESULTS

Black adults underwent 928 PVIs per 100 000 Black beneficiaries compared with 530 PVIs per 100 000 White beneficiaries (risk ratio, 1.75 [95% CI, 1.73-1.77]; P<0.01). Black adults who underwent PVI were younger (mean age, 74.5 years versus 76.4 years; P<0.01), were more likely to be female (52.8% versus 42.7%; P<0.01), and had a higher burden of diabetes (70.6% versus 56.0%; P<0.01), chronic kidney disease (67.5% versus 56.6%; P<0.01), and heart failure (47.4% versus 41.7%; P<0.01) than White adults. When analyzed by indication for revascularization, Black adults were more likely to undergo PVI for chronic limb-threatening ischemia than White adults (13 023 per 21 352 [61.0%] versus 59 956 per 120 049 [49.9%]; P<0.01). There was a strong association between Black race and the composite outcome at 1 year (odds ratio, 1.21 [95% CI, 1.16-1.25]). This association persisted after adjustment for socioeconomic status (odds ratio, 1.08 [95% CI, 1.03-1.13]) but was eliminated after adjustment for comorbidities (odds ratio, 0.96 [95% CI, 0.92-1.01]).

CONCLUSIONS

Among fee-for-service Medicare beneficiaries, Black adults had substantially higher population-level PVI incidence and were significantly more likely to experience adverse events after PVI than White adults. The association between Black race and adverse outcomes appears to be driven by a higher burden of comorbidities. This analysis emphasizes the critical need for early identification and aggressive management of peripheral artery disease risk factors and comorbidities to reduce Black-White disparities in the development and progression of peripheral artery disease and the risk of adverse events after PVI.

Delays to revascularization for patients with chronic limb-threatening ischaemia

BACKGROUND

Vascular services in England are organized into regional hub-and-spoke models, with hubs performing arterial surgery. This study examined time to revascularization for chronic limb-threatening ischaemia (CLTI) within and across different care pathways, and its association with postrevascularization outcomes.

METHODS

Three inpatient and four outpatient care pathways were identified for patients with CLTI undergoing revascularization between April 2015 and March 2019 using Hospital Episode Statistics data. Differences in times from presentation to revascularization across care pathways were analysed using Cox regression. The relationship between postoperative outcomes and time to revascularization was evaluated by logistic regression.

RESULTS

Among 16 483 patients with CLTI, 9470 had pathways starting with admission to a hub or spoke hospital, whereas 7013 (42.5 per cent) were first seen at outpatient visits. Among the inpatient pathways, patients admitted to arterial hubs had shorter times to revascularization than those admitted to spoke hospitals (median 5 (i.q.r. 2-10) versus 12 (7-19) days; P < 0.001). Shorter times to revascularization were also observed for patients presenting to outpatient clinics at arterial hubs compared with spoke hospitals (13 (6-25) versus 26 (15-35) days; P < 0.001). Within most care pathways, longer delays to revascularizsation were associated with increased risks of postoperative major amputation and in-hospital death, but the effect of delay differed across pathways.

CONCLUSION

For patients with CLTI, time to revascularization was influenced by presentation to an arterial hub or spoke hospital. Generally, longer delays to revascularization were associated with worse outcomes, but the impact of delay differed across pathways.

Sex Differences in Peripheral Artery Disease

Peripheral artery disease (PAD) is a prevalent condition that confers substantial morbidity and mortality and remains underdiagnosed as well as undertreated in the overall population. Although PAD prevalence is similar or higher in women compared with men, associations of traditional and nontraditional risk factors with PAD and clinical manifestations of PAD differ by sex and may contribute to delayed or lack of diagnosis in women. Such sex-based differences in the manifestation of PAD may arise from sexual dimorphism in the vascular substrate in health as well as sex variation in the responses to vascular stressors. Despite the availability of proven therapies for improving symptoms and reducing risk of ischemic cardiovascular and limb events among patients with diagnosed PAD, important sex differences in treatment and outcomes have been observed. We provide an overview of current knowledge regarding sex differences in the epidemiology, pathophysiology, clinical presentation, and management of PAD.

Pro-angiogenic approach for skeletal muscle regeneration

The angiogenesis process is a phenomenon in which numerous molecules participate in the stimulation of the new vessels' formation from pre-existing vessels. Angiogenesis is a crucial step in tissue regeneration and recovery of organ and tissue function. Muscle diseases affect millions of people worldwide overcome the ability of skeletal muscle to self-repair. Pro-angiogenic therapies are key in skeletal muscle regeneration where both myogenesis and angiogenesis occur. These therapies have been based on mesenchymal stem cells (MSCs), exosomes, microRNAs (miRs) and delivery of biological factors. The use of different calls of biomaterials is another approach, including ceramics, composites, and polymers. Natural polymers are use due its bioactivity and biocompatibility in addition to its use as scaffolds and in drug delivery systems. One of these polymers is the natural rubber latex (NRL) which is biocompatible, bioactive, versatile, low-costing, and capable of promoting tissue regeneration and angiogenesis. In this review, the advances in the field of pro-angiogenic therapies are discussed.

OUP accepted manuscript

Aims

The prevalence of chronic limb-threatening ischaemia (CLTI) is increasing and available data often derive from cohorts with various selection criteria. In the present study, we included CLTI patients and studied sex-related differences in their risk profile, vascular procedures, and long-term outcome.

Methods and results

We analysed 199 953 unselected patients of the largest public health insurance in Germany (AOK: Local healthcare funds), hospitalized between 2010 and 2017 for a main diagnosis of CLTI. A baseline period of 2 years before index hospitalization to assess comorbidities and previous procedures, and a follow-up period until 2018 were included. Female CLTI patients were older (median 81.4 vs. 73.8 years in males; P < 0.001) and more often diagnosed with hypertension, atrial fibrillation, chronic heart failure, and chronic kidney disease. Male patients suffered more frequently from diabetes mellitus, dyslipidaemia, smoking, cerebrovascular disease, and chronic coronary syndrome (all P < 0.001). Within hospitalized CLTI patients, females represent the minority (43% vs. 57%; P < 0.001) and during index hospitalization, women underwent less frequently diagnostic angiographies (67 vs. 70%) and revascularization procedures (61 vs. 65%; both P < 0.001). Moreover, women received less frequently guideline-recommended drugs like statins (35 vs. 43%) and antithrombotic therapy (48 vs. 53%; both P < 0.001) at baseline. Interestingly, after including age and comorbidities in a Cox regression analysis, female sex was associated with increased overall-survival (OS) [hazard ratio (HR) 0.95; 95% confidence interval (CI) 0.94–0.96] and amputation-free survival (AFS) (HR 0.84; 95% CI 0.83–0.85; both P < 0.001).

Conclusion

Female patients with CLTI were older, underwent less often vascular procedures, and received less frequently guideline-recommended medication. Nevertheless, female sex was independently associated with better OS and AFS during follow-up.

Relationship between Mean Platelet Volume and Critical Limb Ischemia in Diabetes Mellitus Patients

The prevalence of diabetes mellitus continues to increase from year to year. Critical limb ischemia (CLI) is one of the complications of diabetes mellitus with a high mortality rate and requires amputation if not treated properly. Mean platelet volume (MPV) is an indicator of platelet activation and is expected to be a predictor of CLI in diabetes mellitus patients. This article investigates the relationship between MPV and the incidence of CLI in diabetes mellitus patients. This case-control study was conducted using the vascular registry of Dr. Sardjito Hospital, Yogyakarta, Indonesia, from January 2016 to December 2016. The relationship between MPV and the incidence of CLI was analyzed using bivariate and multivariate analysis. There was a significant association between MPV and incidence of CLI in diabetes mellitus patient both on bivariate analysis ( p  = 0.035) and multivariate analysis ( p  = 0.029). Diabetes mellitus patients with MPV values of ≥ 9.8 fl had a protective effect to prevent the incidence of CLI (bivariate analysis: odds ratio [OR] = 0.366, 95% confidence interval [CI] = 0.142-0.943; multivariate analysis: adjusted OR = 0.288, 95% CI = 0.09-0.88). Confounding factors such as sex, age, obesity, and use of antiplatelet agents were not associated with the incidence of CLI ( p  > 0.05). Meanwhile, history of dyslipidemia as a confounding factor was significantly associated with the incidence of CLI ( p  < 0.05). Low MPV was found to be significantly associated with the incidence of CLI in diabetes mellitus patients.

A Swine Hind Limb Ischemia Model Useful for Testing Peripheral Artery Disease Therapeutics

Currently, there is no large animal model of sustained limb ischemia suitable for testing novel angiogenic therapeutics for peripheral artery disease (PAD) such as drugs, genes, materials, or cells. We created a large animal model suitable for efficacy assessment of these therapies by testing 3 swine hind limb ischemia (HLI) variations and quantifying vascular perfusion, muscle histology, and limb function. Ligation of the ipsilateral external and bilateral internal iliac arteries produced sustained gait dysfunction compared to isolated external iliac or unilateral external and internal iliac artery ligations. Hyperemia-dependent muscle perfusion deficits, depressed limb blood pressure, arteriogenesis, muscle atrophy, and microscopic myopathy were quantifiable in ischemic limbs 6 weeks post-ligation. Porcine mesenchymal stromal cells (MSCs) engineered to express a reporter gene were visualized post-administration via positron emission tomography (PET) in vivo. These results establish a preclinical platform enabling better optimization of PAD therapies, including cellular therapeutics, increasing bench-to-bedside translational success. A preclinical platform for porcine studies of peripheral artery disease therapies including (1) a hind limb ischemia model and (2) non-invasive MSC viability and retention assessment via PET.

"Elephant-trunk" negative pressure wound therapy for fixing artificial dermis with basic fibroblast growth factor for critical limb ischemia

INTRODUCTION

The treatment of intractable toe ulcer with critical limb ischemia (CLI) is a challenge because of its poor blood flow and the wound. Here, a novel fixation technique for artificial dermis with negative pressure wound therapy (NPWT) was reported.

METHOD

After the amputation of toe, artificial dermis made of collagen-gelatin sponge (CGS) was grafted onto the wound where human recombinant basic fibroblast growth factor (bFGF) was sprayed. The foot was put on adhesive iodine-impregnated drape, the artificial-dermis area was covered with a sponge dressing of which another end reached to the drape, and the vacuum port was applied on the dressing sponge sandwiched with two drapes and connected to an NPWT system. Since the shape of sponge-dressing was similar to that of elephant-trunk, the technique in this study was named an "Elephant-trunk" technique.

RESULT

During NPWT period, no complications such as air leakage, skin erosion, ischemic around tissue were confirmed. The artificial dermis was engrafted completely at one week after surgery, and the wound was confirmed to close completely.

CONCLUSION

This NPWT technique with bFGF and CGS accelerated the healing of wound treated conservatively with artificial dermis in CLI patients.

The role of directional atherectomy in critical-limb ischemia

Background:

Our aim was to review the current literature of the use of directional atherectomy (DA) in the treatment of lower extremity critical-limb ischemia.

Methods:

A search for relevant literature was performed in PubMed and PubMed Central on 16 April 2020, sorted by best match. Three searches across two databases were performed. Articles were included that contained clinical and procedural data of DA interventions in lower extremity critical-limb ischemia patients. All studies that were systematic reviews were excluded.

Results:

Eleven papers were included in this review. Papers were examined under several parameters: primary patency and secondary patency, limb salvage/amputation, technical/procedural success, complications/periprocedural events, and mean lesion length. Primary and secondary patency rates ranged from 56.3% to 95.0% and 76.4% to 100%, respectively. Limb salvage rates ranged from 69% to 100%. Lesion lengths were highly varied, representing a broad population, ranging from 30 ± 33 mm to 142.4 ± 107.9 mm.

Conclusions:

DA may be a useful tool in the treatment of lower extremity critical-limb ischemia.

Pathogenesis and Clinical Significance of In-Stent Restenosis in Patients with Diabetes

Diabetes mellitus (DM) is a strong risk factor for the development of cardiovascular diseases such as coronary heart disease, cerebrovascular disease, and peripheral arterial disease (PAD). In the population of people living with DM, PAD is characterised by multi-level atherosclerotic lesions as well as greater involvement of the arteries below the knee. DM is also a factor that significantly increases the risk of lower limb amputation. Percutaneous balloon angioplasty with or without stent implantation is an important method of the treatment for atherosclerotic cardiovascular diseases, but restenosis is a factor limiting its long-term effectiveness. The pathogenesis of atherosclerosis in the course of DM differs slightly from that in the general population. In the population of people living with DM, more attention is drawn to such factors as inflammation, endothelial dysfunction, platelet dysfunction, blood rheological properties, hypercoagulability, and additional factors stimulating vascular smooth muscle cell proliferation. DM is a risk factor for restenosis. The purpose of this paper is to provide a review of the literature and to present the most important information on the current state of knowledge on mechanisms and the clinical significance of restenosis and in-stent restenosis in patients with DM, especially in association with the endovascular treatment of PAD. The role of such processes as inflammation, neointimal hyperplasia and neoatherosclerosis, allergy, resistance to antimitotic drugs used for coating stents and balloons, genetic factors, and technical and mechanical factors are discussed. The information on restenosis collected in this publication may be helpful in planning further research in this field, which may contribute to the formulation of more and more precise recommendations for the clinical practice.

Effect on healing rates of wounds treated with direct cold atmospheric plasma: a case series

OBJECTIVE

The response of different critical acute and hard-to-heal wounds to an innovative wound care modality-direct application of cold atmospheric plasma (CAP)-was investigated in this clinical case series.

METHOD

Over an observation period of two years, acute wounds with at least one risk factor for chronification, as well as hard-to-heal wounds were treated for 180 seconds three times per week with CAP. CAP treatment was additional to standard wound care. Photographs were taken for wound documentation. The wound sizes before the first CAP treatment, after four weeks, after 12 weeks and at wound closure/end of observation time were determined using image processing software, and analysed longitudinally for the development of wound size.

RESULTS

A total of 27 wounds (19 hard-to-heal and eight acute wounds) with a mean wound area of 15cm² and a mean wound age of 49 months were treated with CAP and analysed. All (100%) of the acute wounds and 68% of the hard-to-heal wounds healed after an average treatment duration of 14.2 weeks. At the end of the observation period, 21% of hard-to-heal wounds were not yet closed but were reduced in size by >80%. In 11% of the hard-to-heal wounds (n=2) therapy failed.

CONCLUSION

The results suggested a beneficial effect of additional CAP therapy on wound healing.

DECLARATION OF INTEREST

This work was carried out within the research projects 'Plasma for Life' (funding reference no. 13FH6I04IA) with financial support from the German Federal Ministry of Education and Research (BMBF). In the past seven years AFS has provided consulting services to Evonik and has received institutional support by Heraeus, Johnson & Johnson and Evonik. There are no royalties to disclose. The Department for Trauma Surgery, Orthopaedics and Plastic Surgery received charitable donations by CINOGY GmbH. CINOGY GmbH released the di_CAP devices and electrodes for the study. WV and AH were involved in the development of the used di_CAP device (Plasmaderm, CINOGY GmbH). WV is shareholder of the outsourced start-up company CINOGY GmbH.

Efficacy and Safety of Vorapaxar by Intensity of Background Lipid-Lowering Therapy in Patients With Peripheral Artery Disease: Insights From the TRA2P-TIMI 50 Trial

Background Patients with peripheral artery disease are at increased risk of both major adverse cardiovascular events (MACEs) and limb events. The pathobiology of limb events is likely multifactorial. Observational studies suggest a benefit of statin therapy for reducing the risk of limb ischemic events while randomized trials demonstrate a benefit with more potent antithrombotic therapies, particularly those targeting thrombin. Whether the effects of these therapeutic pathways are independent and complementary is not known. Methods and Results The TRA 2°P-TIMI 50 (Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events-Thrombolysis in Myocardial Infarction 50) trial demonstrated that vorapaxar significantly reduced MACEs and limb events. The purpose of the current analysis was to evaluate the association of statin use and intensity and the occurrence of MACEs and limb events in 5845 patients with symptomatic peripheral artery disease randomized in TRA 2°P-TIMI 50 and then to understand whether statin use modified the benefits of vorapaxar for MACEs or limb ischemic events. We found that statin therapy was associated with significantly lower risk of MACEs (hazard ratio [HR], 0.77; 95% CI, 0.66-0.89; P<0.001) and limb ischemic events (HR, 0.73; 95% CI, 0.60-0.89; P=0.002). The benefit of vorapaxar for reducing MACEs and limb events was consistent regardless of background statin (P-interaction=0.715 and 0.073, respectively). Event rates were lowest in patients receiving the combination of statin therapy and vorapaxar. Conclusions In conclusion, statin use and intensity is associated with significantly lower rates of MACEs and limb ischemic events. Thrombin inhibition with vorapaxar is effective regardless of background statin therapy. These results suggest that targeting both lipid and thrombotic risk in peripheral artery disease is necessary in order to optimize outcomes.

A Thermoresponsive Chitosan/β-Glycerophosphate Hydrogel for Minimally Invasive Treatment of Critical Limb Ischaemia

A reduction in blood supply to any limb causes ischaemia, pain and morbidity. Critical limb ischaemia is the most serious presentation of peripheral vascular disease. One in five patients with critical limb ischaemia will die within six months of diagnosis and one in three will require amputation in this time. Improving blood flow to the limb, via the administration of angiogenic agents, could relieve pain and avoid amputation. Herein, chitosan is combined with β-glycerophosphate to form a thermoresponsive formulation (chitosan/β-GP) that will flow through a syringe and needle at room temperature but will form a gel at body temperature. The chitosan/β-GP hydrogel, with or without the angiogenic molecule desferrioxamine (DFO), was injected into the mouse hind limb, following vessel ligation, to test the ability of the formulations to induce angiogenesis. The effects of the formulations were measured using laser Doppler imaging to determine limb perfusion and CD31 staining to quantify the number of blood vessels. Twenty-eight days following induction of ischaemia, the chitosan/β-GP and chitosan/β-GP + 100 µM DFO formulations had significantly (p < 0.001 and p < 0.05, respectively) improved blood flow in the ischaemic limb compared with an untreated control. Chitosan/β-GP increased vessel number by 1.7-fold in the thigh of the ischaemic limb compared with an untreated control, while chitosan/β-GP + 100 µM DFO increased vessel number 1.8-fold. Chitosan/β-GP represents a potential minimally invasive treatment for critical limb ischaemia.

Angiogenic effects of cell therapy within a biomaterial scaffold in a rat hind limb ischemia model

Critical limb ischemia (CLI) is a life- and limb-threatening condition affecting 1-10% of humans worldwide with peripheral arterial disease. Cellular therapies, such as bone marrow-derived mesenchymal stem cells (MSCs) have been used for the treatment of CLI. However, little information is available regarding the angiogenic potency of MSCs and mast cells (MC) in angiogenesis. The aim of this study was to evaluate the ability of MCs and MSCs to induce angiogenesis in a rat model of ischemic hind limb injury on a background of a tissue engineered hydrogel scaffold. Thirty rats were randomly divided into six control and experimental groups as follows: (a) Control healthy (b) Ischemic positive control with right femoral artery transection, (c) ischemia with hydrogel scaffold, (d) ischemia with hydrogel plus MSC, (e) ischemia with hydrogel plus MC and (f) ischemia with hydrogel plus MSC and MCs. 106 of each cell type, isolated from bone marrow stroma, was injected into the transected artery used to induce hind limb ischemia. The other hind limb served as a non-ischemic control. After 14 days, capillary density, vascular diameter, histomorphometry and immunohistochemistry at the transected location and in gastrocnemius muscles were evaluated. Capillary density and number of blood vessels in the region of the femoral artery transection in animals receiving MSCs and MCs was increased compared to control groups (P < 0.05). Generally the effect of MCs and MSCs was similar although the combined MC/MSC therapy resulted in a reduced, rather than enhanced, effect. In the gastrocnemius muscle, immunohistochemical and histomorphometric observation showed a great ratio of capillaries to muscle fibers in all the cell-receiving groups (P < 0.05). The data indicates that the combination of hydrogel and cell therapy generates a greater angiogenic potential at the ischemic site than cell therapy or hydrogels alone.

Reinterventions in Patients with Claudication and Chronic Limb Threatening Ischemia

BACKGROUND

Patients with peripheral artery disease (PAD) present with claudication or chronic limb threatening ischemia (CLTI). CLTI patients have a more advanced stage of atherosclerosis and increased comorbidities compared to claudicants, and are at an elevated risk of major amputation and mortality after lower extremity revascularization (LER). However, the frequency of reinterventions for claudication and CLTI have not been compared. Our hypothesis is that patients with CLTI undergo more frequent reinterventions to prevent major amputation.

METHODS

A single-center retrospective chart review of consecutive patients undergoing lower extremity revascularization (LER) for PAD in 2013-2015 was performed. Patients were stratified based on indication for revascularization into claudication or CLTI. Patient characteristics, outcomes, and reinterventions were compared between the 2 groups.

RESULTS

There were 826 patients undergoing LER and 44% (N = 361) had CLTI. Patients treated for CLTI were more likely to be smokers (P < 0.001), to have diabetes (P< 0.001), chronic renal insufficiency (P< 0.001), end stage renal disease (P< 0.001), and cardiac disease (P< 0.001). CLTI patients were less likely to be on optimal medical management as reflected by decreased rate of aspirin (P< 0.001), ADP receptor/P2Y12 inhibitors (P< 0.001), and statins (P< 0.001) compared to patients with claudication. Patients with CLTI had significantly higher major amputation (3.7% vs. 0.2%, P< 0.001) and mortality (1.4% vs. 0.2%, P = 0.092) at 30 days. At long-term follow up, patients with CLTI had higher rates of major amputation (15.5% vs. 1.3%, P < 0.001) and mortality (37.1% vs. 18.1%, P < 0.001) compared to patients with claudication. There was a significant difference in mean follow-up time between the 2 cohorts (claudication: 3.7 ± 1.5 years versus CLTI: 2.6 ± 1.8 years, P < 0.001). There was no significant difference in the ipsilateral reintervention rate between the 2 groups (claudication: 39.6% vs. CLTI: 42.7%, P = 0.37) or the mean number of ipsilateral reinterventions (claudication: 2.0 ± 1.6 vs. CLTI: 2.0 ± 1.7). However, after adjusting for follow-up time, the mean number of reinterventions per year was significantly higher for CLTI patients compared to patients with claudication (1.4 ± 2.2 vs. .6 ± 0.7 intervention per year, P < 0.001).

CONCLUSIONS

Patients undergoing LER for CLTI undergo more frequent reinterventions over time compared to patients treated for claudication. Research on reinterventions after LER should include reporting of the frequency of reintervention adjusted for the follow up period in addition to the reintervention rate defined as the percentage of patients undergoing reintervention.

Impact of nutritional and inflammatory status in patients with critical limb-threatening ischemia

BACKGROUND

A pro-inflammatory state and a poor nutritional status have been associated with severity and prognosis of patients with peripheral arterial disease (PAD). The clinical applicability of the different pre-operative nutritional and inflammatory biomarkers in patients with critical limb-threatening ischemia (CLTI) was analyzed.

METHODS

A retrospective observational study was performed, that included all patients with CLTI revascularized from January 2016 to July 2019. The inflammatory state was calculated using neutrophil/lymphocyte (NLR), lymphocyte/monocyte (LMR) and platelet/lymphocyte ratios (PLR). For nutritional status, the Prognostic Nutritional Index (PNI) was calculated. Mortality and number of major amputations at 6 months and hospital length-of stay were studied.

RESULTS

310 patients were included. Higher levels of NLR and lower levels of PNI were associated with mortality (6.61±5.6 vs. 3.98±3.27, P=0.034; 40.33±7.89 vs. 45.73±7.48, P=0.05, respectively). Lower levels of PNI and LMR (42.57±7.82 vs. 45.44±7.65, P=0.036; 2.77±1.61 vs. 3.22±1.75, P=0.013, respectively) and higher levels of NLR (6.91±7.85 vs. 3.94±2.57, P=0.023) were associated with major amputations. The mean hospital length-of-stay was higher in patients with lower levels of PNI and LMR (P=0.000 and P=0.003) and higher levels of NLR and PLR (P=0.001 and P=0.002). A PNI<42.87 predicted short-term mortality with a 66.7% of sensitivity and a 66.8% of specificity (P=0.000).

CONCLUSIONS

Our experience suggests that these inflammatory and nutritional biomarkers are independent predictors of short-term mortality and major amputations. In addition, our results suggest that PNI could be used to predict the short-term mortality with high sensitivity and specificity.

Characteristics and outcomes of octogenarians with revascularized critical limb ischemia: Impact of altered cardiac function for early mortality

OBJECTIVE

Patients with critical limb ischemia (CLI) present with advanced age and end-stage organ damage, in particular heart failure. The aim of the present study is to describe clinical and biological characteristics in octogenarian patients with CLI compared to their younger counterparts and to determine the peri-procedural risk and early mortality after endovascular procedure.

METHODS

From November 2013 to May 2019, 315 consecutive patients were retrospectively included. Clinical and biological parameters were recorded at baseline before endovascular revascularization. The main outcome was total 1-year mortality.

RESULTS

The study included 170 octogenarians and 145 non-octogenarians. The mean age of octogenarian patients was 86.9±4.8 years, almost 20 years higher than that registered in non-octagenarians patients (67.4±8.6 years). Octogenarian patients were mostly women (59.4%), presented with lower body mass index (23.8±4.4kg/m²), lower serum albumin level (31.5±5.4g/L) and lower creatinine clearance (66.1±24.5mL/mn) than younger counterparts. They were more likely to be institutionalized in a nursing home (27.1%). In the peri-procedural period, major bleeding occurred in 40 patients (12.7%), without statistical significance between the two age groups. Peri-procedural mortality occurred in 12 patients (3.8%), of whom 10 patients (83%) were octogenarians. Cumulative mortality rate was 25.4% (80 patients) during the one-year follow-up period: 58 octogenarians died (34.1%) compared to 22 non-octogenarian patients (15.2%), P<0.001. Cardiovascular events were highly prevalent, accounting for 40% of overall mortality. Twenty-five patients (8%) experienced major amputation, without significant difference between the two age groups. In octogenarian population, institutionalized status (P=0.004) and BNP level (P=0.001) were positively correlated with mortality whereas systolic blood pressure (P<0.001), left ventricular ejection fraction (P=0.003), serum albumin (P=0.020), C-Reactive protein (P=0.020) and renin-angiotensin system inhibitors at hospital discharge were negatively correlated with mortality. In multivariate analysis for mortality, only BNP level≥500pg/mL (HR 3.27; 95% CI 1.04-10.97; P=0.04), was correlated with mortality, independently of other confounders.

CONCLUSION

In the present study population, octogenarians represent a rather distinct CLI population, 20 years of age older as compared to non-octogenarians, with prevalent malnutrition and institutionalized status. The present results underline a substantial one-year mortality rate of 34.1% in this elderly population following revascularization procedure with a 6% peri-procedural mortality. Decompensated heart failure is an important contributor for mortality.

Antithrombotic Therapy in Peripheral Artery Disease: Stepping in the Right Direction

We reviewed the various antithrombotic therapies available to treat peripheral artery disease (PAD). A literature review using the PubMed and MEDLINE databases used the following keywords: antithrombotic therapy, anticoagulation, peripheral artery disease, and peripheral vascular disease. Randomized studies written in English that assessed the use of antithrombotic therapy in patients with PAD were evaluated. PAD is a worldwide condition that limits blood flow in the lower extremities, leading to a risk of major adverse cardiovascular events and major adverse limb events. Antithrombotic therapy is necessary to prevent these complications, and the choice of therapy depends upon the stage of disease progression. For symptomatic patients in the beginning stage, single antiplatelet therapy (SAPT) is the preferred therapy, specifically, aspirin. For patients undergoing endovascular revascularization, the preferred therapy is dual antiplatelet therapy using aspirin and clopidogrel combined for at least the first month followed by long-term SAPT. For patients undergoing surgical revascularization, the preferred choice of therapy depends upon the type of graft used, with better results obtained with antiplatelet therapy for prosthetic grafts and anticoagulation for venous grafts. New studies have shown that therapy using both antiplatelets and anticoagulation in the form of aspirin plus low-dose rivaroxaban can reduce complications in all three patient populations, which has paved the way for future studies featuring direct oral anticoagulants with the potential to change current guideline recommendations.

Induced endothelial cells from peripheral arterial disease patients and neonatal fibroblasts have comparable angiogenic properties

Induced endothelial cells (iECs) generated from neonatal fibroblasts via transdifferentiation have been shown to have pro-angiogenic properties and are a potential therapy for peripheral arterial disease (PAD). It is unknown if iECs can be generated from fibroblasts collected from PAD patients and whether these cells are pro-angiogenic. In this study fibroblasts were collected from four PAD patients undergoing carotid endarterectomies. These cells, and neonatal fibroblasts, were transdifferentiated into iECs using modified mRNA. Endothelial phenotype and pro-angiogenic cytokine secretion were investigated. NOD-SCID mice underwent surgery to induce hindlimb ischaemia in a murine model of PAD. Mice received intramuscular injections with either control vehicle, or 1 × 106 neonatal-derived or 1 × 106 patient-derived iECs. Recovery in perfusion to the affected limb was measured using laser Doppler scanning. Perfusion recovery was enhanced in mice treated with neonatal-derived iECs and in two of the three patient-derived iEC lines investigated in vivo. Patient-derived iECs can be successfully generated from PAD patients and for specific patients display comparable pro-angiogenic properties to neonatal-derived iECs.

Risk Models and Scores in Patients with Peripheral Artery Disease and Chronic Limb-threatening Ischemia: A Comprehensive Review

Peripheral artery disease (PAD) affects more than 200 million patients worldwide and chronic limbthreatening ischemia (CLTI) is the most advanced stage of PAD with very high morbidity and mortality rates. Cardiovascular medicine is trending towards a more personalized approach where each individual patient will be managed according to specific risk factors, disease characteristics, expectations related to their disease and individualized assessment of potential outcomes. For this reason, a number of risk models and scores have been developed during the last few years. Our aim in this comprehensive review article is to provide an overview of selected risk models and scores for patients with PAD and CLTI. Given that some of the published scores were of low quality (minimal discriminatory ability), we included scores that were already externally validated or scores that had promising initial findings. Available scoring systems were grouped in the five following categories according to their utility: i) scores that can detect asymptomatic patients who should be screened for PAD, ii) scores for assessment of functional status and quality of life in patients with PAD, iii) scores assessing risk for amputation and other major adverse limb events among patients with CLTI, iv) scores for the optimal revascularization strategy in each patient and scores predicting successful procedural outcomes; v) scores predicting short or long-term cardiovascular and limb related outcomes after either revascularization or at least angiographic assessment. Limitations of available scoring systems include development and validation in specific populations, lack of external validation (for some of them) and also lack of synchrony with current era endovascular technology. However, with further optimization of current scores and the development of new scores, the field of PAD and CLI can be transitioned to a personalized medicine approach.

Hydrogel-based therapeutic angiogenesis: An alternative treatment strategy for critical limb ischemia

Critical limb ischemia (CLI) is the most severe clinical manifestation of peripheral arterial disease (PAD), resulting in the total or partial loss of limb function. Although the conventional treatment strategy of CLI (e.g., medical treatment and surgery) can improve blood perfusion and restore limb function, many patients are unsuitable for these strategies and they still face the threats of amputation or death. Therapeutic angiogenesis, as a potential solution for these problems, attempts to manipulate blood vessel growth in vivo for augment perfusion without the help of extra pharmaceutics and surgery. With the rise of interdisciplinary research, regenerative medicine strategies provide new possibilities for treating many clinical diseases. Hydrogel, as an excellent biocompatibility material, is an ideal candidate for delivering bioactive molecules and cells for therapeutic angiogenesis. Besides, hydrogel could precisely deliver, control release, and keep the bioactivity of cargos, making hydrogel-based therapeutic angiogenesis a new strategy for CLI therapy. In this review, we comprehensively discuss the approaches of hydrogel-based strategy for CLI treatment as well as their challenges, and future directions.

Clinical considerations after endovascular therapy of peripheral artery disease

Introduction: Patients with peripheral artery disease (PAD) are at higher risk for all-cause mortality, driven by increased cardiovascular mortality rates. In this manuscript we review the literature on guideline-recommended therapies and discuss the major clinical considerations after endovascular therapy of PAD.Areas covered: Current guidelines recommend smoking cessation, aspirin, statin, and renin-angiotensin system inhibitors in order to reduce the risk of cardiovascular and limb-related adverse events. Nonetheless, studies have shown that patients with PAD are undertreated with these important medical therapies. Additionally, there is lack in evidence regarding the most optimal follow up imaging approach for early detection of disease recurrence and re-intervention among patients undergoing endovascular therapy for PAD. We also describe the benefits of supervised walking exercise for patients with PAD that undergo revascularization procedures and are fit for such interventions.Expert opinion: Adherence to guideline recommended medical therapy is crucial for improved outcomes in PAD management. Systematic assessment of risk-reduction interventions could help increase adherence to clinically beneficial interventions and improve the overall prognosis of patients with PAD undergoing revascularization procedures. Additionally, optimization of current follow up protocols is needed, with the optimal goal to develop standardized cost-effective algorithms regarding early detection of disease recurrence and re-intervention.

Validation of ERICVA Risk Score as a Predictor of One Year Amputation-Free Survival of Patients with Critical Limb Ischemia

Background

The ERICVA score was derived to predict amputation-free survival in patients with critical limb ischemia (CLI). It may be a useful tool to stratify patients in trials of novel interventions to treat CLI but, as yet, it has not been externally validated.

Methods

A prospective database of CLI patients was developed during prescreening of patients for a phase 1 stem cell therapy clinical trial. The primary outcome was amputation free survival (AFS) at 1 year. Both the full ERICVA scale (11 parameters) and simplified ERICVA scale (5 parameters) were validated. Data analysis was performed by calculation of the area under the receiver operating characteristic (ROC) curve examining the predictive value of the scores. The Chi-square test was used to examine the association between risk group and one-year AFS and the cumulative survival of the three risk groups was compared using Kaplan Meier survival curves.

Results

A series of 179 CLI patients were included in the analysis. The Chi-square test of independence showed a significant association between the risk group (high, medium and low) and one-year AFS outcome (P = 0.0007). Kaplan-Meier survival curve showed significant difference in one-year AFS between the three risk groups (log-rank P < 0.001). The area under the curve (AUC) was found to be 0.63 and 0.61 for the full and simplified score, respectively. The sensitivity of the full score was 0.44 with specificity of 0.84. The simplified score had a sensitivity of 0.28 and specificity of 0.92.

Conclusion

The ERICVA risk score system was found to have a fair validity but cannot be considered reliable as a single predictor of one year AFS of CLI patients. The simplified score had an AUC almost identical to the full score and can accordingly replace the full score.

Low admission blood pressure as a marker of poor 1-year survival in patients with revascularized critical limb ischemia

OBJECTIVE

To contrast the association between blood pressure (BP) level and antihypertensive medications at hospital admission with 1-year mortality in patients undergoing revascularization for critical limb ischemia (CLI).

METHODS

From November 2013 to May 2019, 315 consecutive patients were retrospectively included. A median of seven (IQR 3-13) separate readings were recorded for each patient before revascularization procedure and the average represented patient's mean BP. BP-lowering medications, clinical and biological parameters were recorded at baseline. The main outcome was total 1-year mortality.

RESULTS

The cohort included 172 men (55%) and 143 women (45%), with a mean age of 77.9 ± 11.9 years. Treated hypertension was present in 245 (78%) patients; 288 (91%) patients had BP-lowering drug prescriptions (2.1 ± 1.3 medications at baseline). Mean SBP, DBP, mean BP (MBP) and pulse pressure (PP) were 132 ± 18, 70 ± 8, 90 ± 10 and 62 ± 16mmHg. During 1-year follow-up, 80 (25.4%) patients died. In single-pressure multivariate analysis, SBP (hazard ratio 0.97; 95% CI 0.96-0.99; P = 0.005), MBP (hazard ratio 0.96; 95% CI 0.92-0.99; P = 0.01), PP (hazard ratio 0.97; 95% CI 0.95-0.99; P = 0.009), but not DBP, were inversely correlated with 1-year mortality, independently of age, coronary heart disease, left ventricular ejection fraction, brain natriuretic peptide, serum albumin, institutionalized status and antihypertensive drugs. Association between SBP, MBP and PP with 1-year mortality had a quite linear reverse pattern.

CONCLUSION

Among patients undergoing revascularization for CLI, there is an inverse correlation between admission SBP, MBP and PP with 1-year mortality. BP may represent a modifiable therapeutic target to prevent poor outcome in CLI patients.