Management of Critical Limb Ischemia

Simultaneous Hybrid Treatment of Multilevel Peripheral Arterial Disease in Patients with Chronic Limb-Threatening Ischemia

BACKGROUND

Hybrid treatments (HT) aim to reduce conventional open surgery invasiveness and address multilevel peripheral arterial disease (PAD). Herein, the simultaneous HT treatment in patients with chronic limb-threatening ischemia (CLTI) is reported.

METHODS

Retrospective analysis, for the period from May 2012 to April 2018, of patients presenting multilevel PAD with CLTI addressed with simultaneous HT. The outcomes of these interventions were measured the following metrics: early technical successes (within 30 days following treatment) and late technical successes (30 days or more following treatment) and included mortality, morbidity symptoms recurrence, and amputation. Survival and patencies were estimated. The median follow-up was 43.77 months.

RESULTS

In the 45 included patients, the HT consisted of femoral bifurcation patch angioplasty followed by an endovascular treatment in 38 patients (84.4%) and endovascular treatment followed by a surgical bypass in 7 patients (15.6%). Technical success was 100% without perioperative mortality. Eight (17.8%) patients presented early complications without major amputations. During the follow-up, seven (15.6%) deaths occurred and six patients (13.3%) experienced symptoms recurrence, with five of those patients requiring major amputation. An estimated survival time of 5 years, primary patency, and secondary patency was 84.4%, 79.2%, and 83.3% respectively.

CONCLUSIONS

Hybrid treatments are effective in addressing patients presenting with multilevel PAD and CLTI. The common femoral artery involvement influences strategy selection. Larger studies with longer-term outcomes are required to validate the hybrid approach, indications, and results.

Important Role of Concomitant Lymphangiogenesis for Reparative Angiogenesis in Hindlimb Ischemia

[Figure: see text].

Neutrophil-to-lymphocyte ratio associated with an increased risk of mortality in patients with critical limb ischemia

Purpose

Association of the neutrophil-to-lymphocyte ratio (NLR) with mortality has not been comprehensively explored in critical limb ischemia (CLI) patients. We investigated the association between the NLR and clinical outcomes in CLI.

Materials and methods

We retrospectively enrolled consecutive CLI patients between 1/1/2013 and 12/31/2018. Receiver operating characteristic curve analysis determined NLR cutoffs for 1-year in-hospital, all-cause and cardiac-related mortality; major adverse cardiovascular events (MACEs); and major adverse limb events (MALEs).

Results

Among 195 patients (age, 74.0 years, SD: 11.5; 51.8% male; body mass index, 23.4 kg/m², SD: 4.2), 14.4% exhibited acute limb ischemia. After 1 year, patients with NLR>8 had higher in-hospital mortality (21.1% vs. 3.6%, P<0.001), all-cause mortality (54.4% vs. 13.8%, P<0.001), cardiac-related mortality (28.1% vs. 6.5%, P<0.001), MACE (29.8% vs. 13.0%, P = 0.008), and MALE (28.1% vs. 13.0%, P = 0.021) rates than those with NLR<8. In multivariate logistic regression, NLR≥8 was significantly associated with all-cause (P<0.001) and cardiac-related (adjusted HR: 5.286, 95% CI: 2.075–13.47, P<0.001) mortality, and NLR≥6 was significantly associated with MALEs (adjusted HR: 2.804, 95% CI: 1.292–6.088, P = 0.009). Each increase in the NLR was associated with increases in all-cause (adjusted HR: 1.028, 95% CI: 1.008–1.049, P = 0.007) and cardiac-related (adjusted HR:1.027, 95% CI: 0.998–1.057, P = 0.073) mortality but not in-hospital mortality or MACEs.

Conclusion

CLI patients with high NLRs had significantly higher risks of 1-year all-cause and cardiac-related mortality and MALEs. The NLR can be used for prognostic prediction in these patients.

The Association Between Pleural Empyema and Peripheral Arterial Disease in Younger Patients: A Retrospective National Population-Based Cohort Study

Background: To investigate the relationship between pleural empyema (PE) and peripheral arterial disease (PAD).

Methods: We conducted a retrospective cohort study using data from the National Health Institute Research Database. Univariable and multivariable Cox's proportional hazard regressions were performed to investigate the association between PE and the risk of PAD. Kaplan–Meier method and the differences were assessed using a log-rank test.

Results: The overall incidence of PAD was higher in the PE cohort than in the non-PE cohort (2.76 vs. 1.72 per 1,000 person-years) with a crude hazard ratio (HR) of 1.61 [95% confidence interval (CI) = 1.41–1.83]. After adjustment for age, gender, and comorbidities, patients with PE were noted to be associated with an increased risk of PAD compared with those without PE [adjusted HR (aHR) = 1.18, 95% CI = 1.03–1.35]. Regarding the age-specific comparison between the PE and non-PE cohorts, PAD was noted to be significantly high in the ≤ 49 years age group (aHR = 5.34, 95% CI = 2.34–10.1). The incidence of PAD was higher in the first 2 years, with an aHR of 1.35 (95% CI = 1.09–1.68) for patients with PE compared with those without PE.

Conclusion: The risk of PAD was higher if patients with PE were younger than 49 years and within the 2-year diagnosis of PE.

Therapeutic angiogenesis using zinc oxide nanoflowers for the treatment of hind limb ischemia in rat model

Critical limb ischemia (CLI) is considered as a severe type of peripheral artery diseases (PADs) which occurs due to the inadequate supply of blood to the limb extremities. CLI patients often suffer from extreme cramping pain, impaired wound healing, immobility, cardiovascular complications, amputation of the affected limb and even death. The conventional therapy for the treatment of CLI includes surgical revascularization as well as restoring angiogenesis using growth factor therapy. However, surgical revascularization is suitable for only a minor percentage of CLI patients and it is associated with high perioperative mortality rate. The use of growth factors is also limited in terms of their poor therapeutic angiogenesis potential as observed by the earlier clinical studies, which could be attributed to their poor bio-availability and non-specificity issues. Therefore, to outweigh the aforesaid disadvantages of the conventional strategies, there is an utmost need for the advancement of new alternative therapeutic biomaterials to treat CLI. Since past few decades, various research groups including ours have been involved in developing different pro-angiogenic nanomaterials. Among them, zinc oxide nanoflowers (ZONF), established in our laboratory, are considered as one of the potent nanoparticles to induce therapeutic angiogenesis. In our earlier studies, we have depicted that ZONF promote angiogenesis by inducing the formation of reactive oxygen species (ROS) and nitric oxide (NO) as well as activating Akt/MAPK/eNOS cell signaling pathways in the endothelial cells. Recently, we have also reported the therapeutic potential of ZONF to treat cerebral ischemia through their neuritogenic and neuroprotective properties, exploiting angio-neural cross talk. Considering the excellent pro-angiogenic properties of ZONF and importance of revascularization for the recovery of CLI, in this present study, we have comprehensively explored the therapeutic potential of ZONF in a rat hind limb ischemia model (established by ligating the femoral artery of hind limb), an animal model that mimics CLI in humans. The behavioural studies, laser Doppler perfusion imaging, histopathology, immunofluorescence as well as estimation of serum NO level depicted that the administration of ZONF could ameliorate the ischemic conditions in rats at a faster rate by promoting therapeutic angiogenesis to the ischemic sites. Altogether, the present study offers an alternative nanomedicine approach employing ZONF for the treatment of PADs.

Contemporary Endovascular 30-Day Outcomes for Critical Limb Threatening Ischemia Relative to Surgical Bypass Grafting

OBJECTIVES

Data from 2011-2014 showed lower extremity bypass(LEB) outperforming infrainguinal endovascular intervention(IEI) regarding major adverse limb events(MALE) but noted no significant difference in major adverse cardiac events(MACE) in propensity matched cohorts. This study aimed to determine if more recent(2015-2018) endovascular outcomes data have improved relative to surgical bypass.

METHODS

Patients who underwent intervention for chronic limb threatening ischemia (CLTI) from 2015-2018 were identified using the American College of Surgeons National Quality Improvement Program(NSQIP) Vascular Surgery module. The cohort was categorized as undergoing lower extremity bypass(LEB) or infrainguinal endovascular intervention(IEI). Primary 30-day outcomes included major adverse cardiac events(MACE), major adverse limb events(MALE), and major amputation. Inverse probability weighting was used for multivariable analysis.

RESULTS

A total of 10,783 patients underwent an infrainguinal intervention for CLTI from 2015-2018. Of these, 6,003(55.7%) underwent LEB and 4,780(44.3%) underwent IEI. Forty percent of the cohort was considered "high anatomic risk" by Objective Performance Goals(OPG) standards, and 13.6% were considered "high clinical risk." The IEI cohort vs. the LEB cohort experienced a Myocardial infarction(MI)/Stroke rate of 1.8% vs. 3.6%(p < .001), and had a mortality rate of 2.0% vs. 1.7%(p = .22), which yielded a composite MACE of 3.4% vs. 4.8%(p = .001). The rate of reintervention for IEI vs LEB was 4.4% vs. 5.3%(p = .04), the loss of patency (without re-intervention) rate was 1.8% vs. 1.8%(p = 1.0), and the major amputation rate was 4.1% vs. 3.5%(p = .15), which resulted in a MALE rate of 9.1% vs. 8.8%(p = .50). Following inverse probability weighting, comparing the IEI to the referent LEB, MALE AOR = 1.17, 95% CI[1.01 -1.36], p = .036, MACE AOR = 0.61, 95% CI[0.49-0.74], p < .001, and major amputation AOR = 1.31, 95% CI[1.05 -1.62], p = .016.

CONCLUSION

Endovascular outcomes continue to demonstrate inferiority in major amputation and overall MALE. However, endovascular intervention has a significantly reduced incidence of MACE. Overall, these results demonstrate an improvement in endovascular MACE rates in recent years relative to surgical bypass.

Economic model to examine the cost-effectiveness of FlowOx home therapy compared to standard care in patients with peripheral artery disease

BACKGROUND

Critical limb ischaemia is a severe stage of lower limb peripheral artery disease which can lead to tissue loss, gangrene, amputation and death. FlowOx™ therapy is a novel negative-pressure chamber system intended for home use to increase blood flow, reduce pain and improve wound healing for patients with peripheral artery disease and critical limb ischaemia.

METHODS

A Markov model was constructed to assess the relative cost-effectiveness of FlowOx™ therapy compared to standard care in lower limb peripheral artery disease patients with intermittent claudication or critical limb ischaemia. The model used data from two European trials of FlowOx™ therapy and published evidence on disease progression. From an NHS analysis perspective, various FlowOx™ therapy scenarios were modelled by adjusting the dose of FlowOx™ therapy and the amount of other care received alongside FlowOx™ therapy, in comparison to standard care.

RESULTS

In the base case analysis, consisting of FlowOx™ therapy plus nominal care, the cost estimates were £12,704 for a single dose of FlowOx™ therapy per annum as compared with £15,523 for standard care. FlowOx™ therapy patients gained 0.27 additional quality adjusted life years compared to standard care patients. This equated to a dominant incremental cost-effectiveness ratio per QALY gained. At the NICE threshold WTP of £20,000 and £30,000 per QALY gained, FlowOx™ therapy in addition to standard care had a 0.80 and 1.00 probability of being cost-effectiveness respectively.

CONCLUSIONS

FlowOx™ therapy delivered as a single annual dose may be a cost-effective treatment for peripheral artery disease. FlowOx™ therapy improved health outcomes and reduced treatment costs in this modelled cohort. The effectiveness and cost-effectiveness of FlowOx™ therapy is susceptible to disease severity, adherence, dose and treatment cost. Research assessing the impact of FlowOx™ therapy on NHS resource use is needed in order to provide a definitive economic evaluation.

Outcome after Hybrid Outflow Interventions for Chronic Limb-threatening Ischemia

BACKGROUND AND AIMS

Because chronic limb-threatening ischemia (CLTI) is often associated with multilevel arterial disease, it usually requires revascularization at different sites of the limb vasculature. We aim to assess the outcome of the hybrid interventions including open surgical revascularization together with outflow segment percutaneous transluminal angioplasty (PTA) in patients with chronic limb-threatening ischemia.

MATERIAL AND METHODS

This study included all hybrid outflow-PTA interventions (n = 80) on patients suffering from CLTI performed in Helsinki University Hospital between 2003 and 2015. Follow-up ended on 31 December 2019. Patient data were prospectively collected into our vascular registry and scrutinized retrospectively. Thirty-one patients (39%) suffered from rest pain (Rutherford category IV) and 49 patients (61%) had ischemic ulcers (Rutherford category V-VI). The most common open surgical procedure was femoral endarterectomy (n = 63, 79%) and the most common endovascular procedure was superficial femoral artery percutaneous transluminal angioplasty (n = 65, 81%). Mean follow-up time was 56 months (range: 4 days-183 months).

RESULTS

Limb salvage was at 30 days-92%, at 1 year-91%, and at 5 and 10 years-86%. Survival and amputation-free survival were at 30 days-93% and 86%, at 1 year-80% and 76%, at 5 years-51% and 48%, and at 10 years-21% and 21%. Wound healing at 3, 6, and 12 months was 48%, 71%, and 87%. Freedom from target lesion revascularization was at 30 days-97%, at 1 year-88%, at 5 years-72%, and at 10 years-66%.

CONCLUSION

Hybrid outflow revascularization is an important tool in the vascular surgeon's armamentarium for treatment of patients with multilevel arterial disease causing chronic limb-threatening ischemia.

Fabrication of New Hybrid Scaffolds for in vivo Perivascular Application to Treat Limb Ischemia

Cell therapies are emerging as a new therapeutic frontier for the treatment of ischemic disease. However, femoral occlusions can be challenging environments for effective therapeutic cell delivery. In this study, cell-engineered hybrid scaffolds are implanted around the occluded femoral artery and the therapeutic benefit through the formation of new collateral arteries is investigated. First, it is reported the fabrication of different hybrid “hard-soft” 3D channel-shaped scaffolds comprising either poly(ε-caprolactone) (PCL) or polylactic-co-glycolic acid (PLGA) and electro-spun of gelatin (GL) nanofibers. Both PCL-GL and PLGA-GL scaffolds show anisotropic characteristics in mechanical tests and PLGA displays a greater rigidity and faster degradability in wet conditions. The resulting constructs are engineered using human adventitial pericytes (APCs) and both exhibit excellent biocompatibility. The 3D environment also induces expressional changes in APCs, conferring a more pronounced proangiogenic secretory profile. Bioprinting of alginate-pluronic gel (AG/PL), containing APCs and endothelial cells, completes the hybrid scaffold providing accurate spatial organization of the delivered cells. The scaffolds implantation around the mice occluded femoral artery shows that bioengineered PLGA hybrid scaffold outperforms the PCL counterpart accelerating limb blood flow recovery through the formation arterioles with diameters >50 μm, demonstrating the therapeutic potential in stimulating reparative angiogenesis.

Contemporary Endovascular Outcomes for Critical Limb Ischemia Are Still Failing to Meet Society for Vascular Surgery Objective Performance Goals

OBJECTIVES

The Society for Vascular Surgery (SVS) created Objective Performance Goals (OPGs) for critical limb ischemia (CLI) in 2009. It was previously shown that endovascular therapy for CLI was not meeting these benchmarks. The OPG for all peripheral interventions is <8% for major adverse cardiac events (MACE), <8% for major adverse limb events (MALE), and <3% for major amputation. The goal of this study is to evaluate if outcomes have improved for CLI in recent years, specifically 2015-2018.

METHODS

The Targeted Vascular Module from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) was queried to identify patients who underwent endovascular intervention for critical limb ischemia from 2011-2018. Cohorts were divided into 2011-2014 and 2015-2018. Primary 30-day outcomes were MACE, MALE, and major amputation. Univariate analyses were performed using the Fisher's exact test and the Wilcoxon rank-sum test. Multivariate analysis comparing groups was performed using inverse probability weights and trend over time analysis was performed using logistic regression with year of intervention as a continuous variable.

RESULTS

From 2011 to 2018, 7,168 patients underwent an endovascular intervention for CLI. 28% were classified as "OPG high anatomic risk," and 17% were classified as "OPG high clinical risk." The 2015-2018 cohort vs. the 2011-14 cohort experienced MACE in 3.3% vs. 2.7% (p = .23), MALE in 9.1% vs. 8.9% (p = 0.83), and amputation in 4.0% vs. 4.2% (p = 0.71). When only high anatomic risk patients were considered (n = 1988), MACE was experienced in 2.4% vs. 2.2% (p = 0.87), MALE by 9.5% vs. 10.6% (p = 0.47) and amputation by 5.1% vs. 6.0% (p = 0.40). When only high clinical risk patients were considered (n = 1224), MACE was experienced in 5.2% vs. 3.9% (p = 0.33), MALE by 8.0% vs. 7.4% (p = 0.74) and amputation by 3.9% vs. 3.7% (p = 0.88). Comparing 2015-2018 to the reference 2011-2014, MALE adjusted odds ratio (AOR) = 0.99, 95% CI [0.83-1.18], MACE AOR = 1.19 95% CI [0.88-1.60], and major amputation AOR = 0.91 95% CI [0.70-1.17]. There were no decreases in the trend over time for MALE (AOR per year 0.97, CI [.94-1.02], major amputation (AOR per year: 0.97, CI [0.91-1.03], nor for MACE (AOR per year: 1.05, CI [.98-1.13]).

CONCLUSION

Outcomes following endovascular interventions for CLI continue to underperform when compared to OPG benchmarks for MALE and amputations. There is no decrease over time for these target outcomes. Target MACE events remain acceptable despite the increasing clinical complexity of patients being treated.

Involvement of microcirculation in critical ischemia: how to identify it?

Critical limb ischemia represents the most severe pattern of peripheral arterial disease (PAD) associated with the high risk of major amputation, cardiovascular events and death. The diagnosis and management of critical limb ischemia (CLI) is often challenging. Systolic ankle and toe pressure measurements are considered to be the basic techniques for the identification of PAD. However, they provide rough insight into the dependent local tissue perfusion. Furthermore, those techniques do not enable investigation of microcirculation which has crucial role in the pathogenesis of CLI. Some patients with mild deterioration of macrocirculation develop CLI if microcirculation is affected. Investigation of perfusion on macro- and local microcirculatory level enables more effective treatment: revascularization of the angiosome-related artery. The technologies capable of assessing limb tissue oxygenation or perfusion on microcirculatory level enable direct assessment of distant tissue oxygenation. Transcutaneous oxygen tension (TcPO2) measurement which was introduced in clinical practice represents one of the objective criteria for the diagnosis of CLI. Main weakness of this technique as well as laser Doppler flow measurement is low penetrance from the skin surface. Measurement of tissue blood flow on microcirculatory level can be performed with indocyanine green fluorescent imaging (ICG), contrast-enhanced magnetic resonance and vital microscopy. ICG is promising method which provides excellent informative image of tissue perfusion. However, it offers little quantitative information. Investigation of microcirculation in patients with CLI is of outmost importance because it enables insight in local tissue perfusion and oxygenation, which represents the basis of identification of most ischemic regions and provide more successful angiosome related revascularization of an affected artery.

Lower extremity revascularization via endovascular and surgical approaches: A systematic review with emphasis on combined inflow and outflow revascularization

This review is intended to help clinicians and patients understand the present state of peripheral artery disease, appreciate the progression and presentation of critical limb ischemia/chronic limb-threatening ischemia, and make informed decisions regarding inflow and outflow endovascular revascularization and surgical treatment options within the context of current debates in the medical community. A controlled literature search was performed to obtain research on outcomes of critical limb ischemia patients undergoing complete leg revascularization for peripheral artery disease inflow and outflow disease. Data for this review were identified by queries of medical and life science databases, expert referral, and references from relevant papers published between 1997 and 2019, resulting in 48 articles. The literature review herein indicates that endovascular revascularization-including ballooning, stenting, and atherectomy-is an effective peripheral artery disease therapy for both above the knee and below the knee disease, and can safely and effectively treat both inflow and outflow disease. As such, it plays a leading role in the therapy of lower extremity artery disease.

Digital Subtraction Angiography Prior to an Amputation for Critical Limb Ischemia (CLI): An Expert Recommendation Statement From the CLI Global Society to Optimize Limb Salvage

Despite recent guideline updates on peripheral artery disease (PAD) and critical limb ischemia (CLI) treatment, the optimal treatment for CLI is still being debated. As a result, care is inconsistent, with many CLI patients undergoing an amputation prior to what many consider to be mandatory: consultation with an interdisciplinary specialty care team and a comprehensive imaging assessment. More importantly, quality imaging is critical in CLI patients with below-the-knee disease. Therefore, the CLI Global Society has put forth an interdisciplinary expert recommendation for superselective digital subtraction angiography (DSA) that includes the ankle and foot in properly indicated CLI patients to optimize limb salvage. A recommended imaging algorithm for CLI patients is included.

Vascular Positron Emission Tomography and Restenosis in Symptomatic Peripheral Arterial Disease: A Prospective Clinical Study

OBJECTIVES

This study determined whether in vivo positron emission tomography (PET) of arterial inflammation (¹⁸F-fluorodeoxyglucose [¹⁸F-FDG]) or microcalcification (¹⁸F-sodium fluoride [¹⁸F-NaF]) could predict restenosis following PTA.

BACKGROUND

Restenosis following lower limb percutaneous transluminal angioplasty (PTA) is common, unpredictable, and challenging to treat. Currently, it is impossible to predict which patient will suffer from restenosis following angioplasty.

METHODS

In this prospective observational cohort study, 50 patients with symptomatic peripheral arterial disease underwent ¹⁸F-FDG and ¹⁸F-NaF PET/computed tomography (CT) imaging of the superficial femoral artery before and 6 weeks after angioplasty. The primary outcome was arterial restenosis at 12 months.

RESULTS

Forty subjects completed the study protocol with 14 patients (35%) reaching the primary outcome of restenosis. The baseline activities of femoral arterial inflammation (¹⁸F-FDG tissue-to-background ratio [TBR] 2.43 [interquartile range (IQR): 2.29 to 2.61] vs. 1.63 [IQR: 1.52 to 1.78]; p < 0.001) and microcalcification (¹⁸F-NaF TBR 2.61 [IQR: 2.50 to 2.77] vs. 1.69 [IQR: 1.54 to 1.77]; p < 0.001) were higher in patients who developed restenosis. The predictive value of both ¹⁸F-FDG (cut-off TBR_max value of 1.98) and ¹⁸F-NaF (cut-off TBR_max value of 2.11) uptake demonstrated excellent discrimination in predicting 1-year restenosis (Kaplan Meier estimator, log-rank p < 0.001).

CONCLUSIONS

Baseline and persistent femoral arterial inflammation and micro-calcification are associated with restenosis following lower limb PTA. For the first time, we describe a method of identifying complex metabolically active plaques and patients at risk of restenosis that has the potential to select patients for intervention and to serve as a biomarker to test novel interventions to prevent restenosis.

Long-Term Clinical Outcomes of Autologous Bone Marrow Mononuclear Cell Implantation in Patients With Severe Thromboangiitis Obliterans

BACKGROUND

Patients with severe Buerger disease, also known as thromboangiitis obliterans (TAO), are at risk of major limb amputation. It has been shown that autologous bone marrow mononuclear cell (BM-MNC) implantation improves the condition of critical limb ischemia in TAO patients. This study was conducted to further clarify the long-term (>10 years) results of autologous BM-MNC implantation in patients with TAO.Methods and Results:An observational study was conducted of the long-term results of BM-MNC implantation in 47 lower limbs of 27 patients with TAO. The mean (±SD) follow-up period was 12.0±8.6 years. There was no major amputation event up to 10 years of follow-up in patients treated with BM-MNC implantation. The overall amputation-free survival rates were significantly higher in patients who underwent BM-MNC implantation than in internal controls and historical controls. There was no significant difference in amputation-free survival rates between the historical and internal controls. There was also no significant difference in overall survival between patients who underwent BM-MNC implantation and the historical controls.

CONCLUSIONS

BM-MNC transplantation successfully prevented major limb amputation over a period of >10 years in patients with severe TAO who had no other therapeutic options.

The Role of Clopidogrel in 2020: A Reappraisal

Antiplatelet therapy is the mainstay of treatment and secondary prevention of cardiovascular disease (CVD), including acute coronary syndrome (ACS), transient ischemic attack (TIA) or minor stroke, and peripheral artery disease (PAD). The P2Y12 inhibitors, of which clopidogrel was the first, play an integral role in antiplatelet therapy and therefore in the treatment and secondary prevention of CVD. This review discusses the available evidence concerning antiplatelet therapy in patients with CVD, with a focus on the role of clopidogrel. In combination with aspirin, clopidogrel is often used as part of dual antiplatelet therapy (DAPT) for the secondary prevention of ACS. Although newer, more potent P2Y12 inhibitors (prasugrel and ticagrelor) show a greater reduction in ischemic risk compared with clopidogrel in randomized trials of ACS patients, these newer P2Y12 inhibitors are often associated with an increased risk of bleeding. Deescalation of DAPT by switching from prasugrel or ticagrelor to clopidogrel may be required in some patients with ACS. Furthermore, real-world studies of ACS patients have not confirmed the benefits of the newer P2Y12 inhibitors over clopidogrel. In patients with very high-risk TIA or stroke, short-term DAPT with clopidogrel plus aspirin for 21-28 days, followed by clopidogrel monotherapy for up to 90 days, is recommended. Clopidogrel monotherapy may also be used in patients with symptomatic PAD. In conclusion, there is strong evidence supporting the use of clopidogrel antiplatelet therapy in several clinical settings, which emphasizes the importance of this medication in clinical practice.

Risk of undiagnosed coronary artery disease associated with infrapopliteal artery occlusion from a multicenter study

Peripheral artery disease (PAD) is associated with high cardiovascular mortality. Which part of PAD with lower extremities is related to coronary artery disease (CAD) remains unknown. We hypothesized that PAD including infrapopliteal artery (IPA) occlusion was associated with CAD. A total of 260 patients who have no history of CAD or the anginal symptom, complain of the claudication or critical limb ischemia and underwent peripheral angiography were retrospectively analyzed. IPA occlusion was diagnosed with peripheral angiography, and CAD was diagnosed with the coronary angiography. A multivariate logistic regression analysis was performed to determine the predictors of silent CAD. Among them, a total of 146 patients (56.2%) had IPA occlusion. Baseline characteristics were significantly different between two groups as to the proportions of age, male, dyslipidemia (with vs. without IPA occlusion; 72.4 ± 10.8 vs. 69.1 ± 10.2; 62.3% vs. 75.4%; 38.6% vs. 52.6%, respectively, all comparisons P < 0.05). Notably, the prevalence of CAD was significantly higher in patients with IPA occlusion (50.7% vs. 34.2%, P = 0.008). On a multivariate analysis, IPA occlusion was an independent predictor for the presence of silent CAD (OR, 1.94; CI, 1.09-3.44, P = 0.024), but aortoiliac artery occlusion (OR, 1.16; CI, 0.53-2.56, P = 0.71) and femoropopliteal artery occlusion (OR, 1.02; CI, 0.57-1.83, P = 0.96) were not. IPA occlusion was associated with silent CAD. Vascular surgeons, interventional radiologists, as well as interventional cardiologists should recognize IPA occlusion as a risk factor of silent CAD.

Dynamic Volume Perfusion CT of the Foot in Critical Limb Ischemia: Response to Percutaneous Revascularization

OBJECTIVE. The purpose of this study was to assess the reproducibility and validity of quantitative perfusion parameters derived from dynamic volume perfusion CT in patients with critical limb ischemia (CLI) and to evaluate perfusion parameter changes before and after endovascular revascularization. SUBJECTS AND METHODS. Patients with CLI referred for unilateral extremity endovascular arterial recanalization were enrolled in this study. CT examinations obtained 1-3 days before the procedure and then within 1 week after the treatment were evaluated at two reading sessions. Blood flow (BF), blood volume (BV), and time to peak (TTP) were measured on color-coded maps and compared statistically. Intraobserver agreement was assessed using intraclass correlation coefficient (ICC) and Bland-Altman analysis. RESULTS. Endovascular treatment was technically successful for all 16 patients. The posttreatment BF and BV showed a statistically significant increase in both dermal and muscle areas (p < 0.05). The posttreatment TTP shortened at a statistically significant level (p < 0.05). In the 3-month clinical follow-up period, the limb salvage rate was 81% and the percentage change in BF and BV of patients with poor response to treatment had no statistically significant increase after treatment, consistent with the clinical assessment. The percentage change in BF and BV correlated well with the improvement of the clinical condition (r = 0.673-0.901). ICC values showed excellent agreement in the range of 0.95-0.98. CONCLUSION. As a reproducible method, dynamic volume perfusion CT of the foot may enable quantitative evaluation of the perfusion of soft tissues and also provide a novel approach to assessing response to endovascular recanalization in CLI.

Long non-coding RNA GAPLINC promotes angiogenesis by regulating miR-211 under hypoxia in human umbilical vein endothelial cells

In this study, we investigated the role of a long non-coding RNA GAPLINC in angiogenesis using human umbilical vein endothelial cells (HUVEC). We found that hypoxia and hypoxia-inducible factor 1α (HIF-1α) increased the expression of GAPLINC in HUVEC cells. Moreover, GAPLINC overexpression down-regulated miR-211 and up-regulated Bcl2 protein expression. Further rescue experiments confirmed that hypoxia directly increased GAPLINC expression. GAPLINC overexpression also increased cell migration and vessel formation which promoted angiogenesis, and these changes were attributed to the increased expression of vascular endothelial growth factor receptors (VEGFR) and delta-like canonical notch ligand 4 (DLL4) receptors. Finally, we demonstrated that GAPLINC promotes vessel formation and migration by regulating MAPK and NF-kB signalling pathways. Taken together, these findings comprehensively demonstrate that overexpression of GAPLINC increases HUVEC cells angiogenesis under hypoxia condition suggesting that GAPLINC can be a potential target for critical limb ischaemia (CLI) treatment.

Peripheral arterial disease: Scoping review of patient-centred outcomes

Peripheral arterial disease (PAD) impairs patients' quality of life (QOL), walking and ulcer healing, increasing patient pain, costs, and risks of amputation or mortality. A literature appraisal described PAD treatment capacity to improve validated patient-centred outcomes in controlled clinical studies. The PUBMED database was searched from 1 January 1970 to 21 June 2018, for original and derivative controlled clinical trial references addressing MeSH terms for 'ischemia' AND 'leg ulcer'. Non-ischemic ulcer treatment references were excluded. Frequencies of improved (P < .05) outcomes were reported. Eighty-eight studies on 4153 patients were summarized. Walking, pain or QOL improved mainly for interventions administered before PAD became severe. Amputation incidence, pain and ulcer healing were more frequently reported in those with severe PAD. Independent of PAD severity, patients experienced more likely improved walking, QOL, or pain reduction in response to structured walking interventions or those increasing calf muscle activity. Those with more severe PAD were more likely to report amputation reduction, mainly in response to invasive interventions. Those with PAD experienced more consistently improved patient-centred outcomes if they received multidisciplinary PAD management with supervised walking or calf muscle activity, with more likely amputation risk reduced for those with more severe PAD.

Critical limb ischemia: Current and novel therapeutic strategies

Critical limb ischemia (CLI) is the advanced stage of peripheral artery disease spectrum and is defined by limb pain or impending limb loss because of compromised blood flow to the affected extremity. Current conventional therapies for CLI include amputation, bypass surgery, endovascular therapy, and pharmacological approaches. Although these conventional therapeutic strategies still remain as the mainstay of treatments for CLI, novel and promising therapeutic approaches such as proangiogenic gene/protein therapies and stem cell-based therapies have emerged to overcome, at least partially, the limitations and disadvantages of current conventional therapeutic approaches. Such novel CLI treatment options may become even more effective when other complementary approaches such as utilizing proper bioscaffolds are used to increase the survival and engraftment of delivered genes and stem cells. Therefore, herein, we address the benefits and disadvantages of current therapeutic strategies for CLI treatment and summarize the novel and promising therapeutic approaches for CLI treatment. Our analyses also suggest that these novel CLI therapeutic strategies show considerable advantages to be used when current conventional methods have failed for CLI treatment.

Radiotracer Imaging Allows for Noninvasive Detection and Quantification of Abnormalities in Angiosome Foot Perfusion in Diabetic Patients With Critical Limb Ischemia and Nonhealing Wounds

Background:

Single photon emission computed tomography (SPECT)/computed tomography (CT) imaging allows for assessment of skeletal muscle microvascular perfusion but has not been quantitatively assessed in angiosomes, or 3-dimensional vascular territories, of the foot. This study assessed and compared resting angiosome foot perfusion between healthy subjects and diabetic patients with critical limb ischemia (CLI). Additionally, the relationship between SPECT/CT imaging and the ankle–brachial index—a standard tool for evaluating peripheral artery disease—was assessed.

Methods and Results:

Healthy subjects (n=9) and diabetic patients with CLI and nonhealing ulcers (n=42) underwent SPECT/CT perfusion imaging of the feet. CT images were segmented into angiosomes for quantification of relative radiotracer uptake, expressed as standardized uptake values. Standardized uptake values were assessed in ulcerated angiosomes of patients with CLI and compared with whole-foot standardized uptake values in healthy subjects. Serial SPECT/CT imaging was performed to assess uptake kinetics of technetium-99m-tetrofosmin. The relationship between angiosome perfusion and ankle–brachial index was assessed via correlational analysis. Resting perfusion was significantly lower in CLI versus healthy subjects (P=0.0007). Intraclass correlation coefficients of 0.95 (healthy) and 0.93 (CLI) demonstrated excellent agreement between serial perfusion measurements. Correlational analysis, including healthy and CLI subjects, demonstrated a significant relationship between ankle–brachial index and SPECT/CT (P=0.01); however, this relationship was not significant for diabetic CLI patients only (P=0.2).

Conclusions:

SPECT/CT imaging assesses regional foot perfusion and detects abnormalities in microvascular perfusion that may be undetectable by conventional ankle–brachial index in patients with diabetes mellitus. SPECT/CT may provide a novel approach for evaluating responses to targeted therapies.

Circulating exosomal miRNAs in cardiovascular disease pathogenesis: New emerging hopes

Cardiovascular diseases (CVDs) are one of the leading causes of morbidity and mortality. Standard therapies have failed to significantly increase patients' survival. Moreover, the majority of conventional screening procedures are ineffective for the diagnosis of CVDs at early stages. Accumulating evidence suggests that numerous cell types release a class of nano-sized vesicles named exosomes into the extracellular space. Exosomes are widely distributed in various body fluids and contain a number of diverse biomolecules such as proteins, lipids, and both mRNA and noncoding RNAs which reflect host-cell molecular architecture. MicroRNAs (miRNAs), which can be found in exosomes, could be taken up by both neighboring and distal cells. Not only has recent evidence indicated the regulatory role of exosomal miRNAs in the pathogenesis of CVD, but it has also been shown that differential expression of exosomal miRNAs in CVDs has made them promising biomarkers for early detection of CVDs. Owing to these remarkable features, exosomal miRNAs have emerged as hot spots in research. This review summarizes the role of exosomal miRNAs in the pathogenesis of CVDs and discusses their potential application in the clinical setting as both therapeutic and diagnostic tools.

Medial artery calcification increases neointimal hyperplasia after balloon injury

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

Nutritional Considerations for Peripheral Arterial Disease: A Narrative Review

Those with peripheral arterial disease (PAD) require important considerations with respect to food and nutrition, owing to advanced age, poor diet behaviours and immobility associated with the disease process and co-morbid state. These considerations, coupled with the economic effectiveness of medical nutrition therapy, mandate that dietetic care plays a vital role in the management of PAD. Despite this, optimising dietetic care in PAD remains poorly understood. This narrative review considers the role of medical nutrition therapy in every stage of the PAD process, ranging from the onset and initiation of disease to well established and advanced disease. In each case, the potential benefits of traditional and novel medical nutrition therapy are discussed.

Review of the Long-term Effects of Autologous Bone-Marrow Mononuclear Cell Implantation on Clinical Outcomes in Patients with Critical Limb Ischemia

Critical limb ischemia (CLI) is associated with a high risk of limb amputation. It has been shown that cell therapy is safe and has beneficial effects on ischemic clinical symptoms in patients with CLI. The aim of this study was to further investigate the outcomes of intramuscular injection of autologous bone-marrow mononuclear cells (BM-MNCs) in a long-term follow-up period in atherosclerotic peripheral arterial disease (PAD) patients who have no optional therapy. This study was a retrospective and observational study that was carried out to evaluate long-term clinical outcomes in 42 lower limbs of 30 patients with atherosclerotic PAD who underwent BM-MNC implantation. The median follow-up period was 9.25 (range, 6–16) years. The overall amputation-free rates were 73.0% at 5 years after BM-MNC implantation and 70.4% at 10 years in patients with atherosclerotic PAD. The overall amputation-free rates at 5 years and at 10 years after implantation of BM-MNCs were significantly higher in atherosclerotic PAD patients than in internal controls and historical controls. There were no significant differences in amputation rates between the internal control group and historical control group. The rate of overall survival was not significantly different between the BM-MNC implantation group and the historical control group. Implantation of autologous BM-MNCs is feasible for a long-term follow-up period in patients with CLI who have no optional therapy.

Restenosis is associated with prothrombotic plasma fibrin clot characteristics in endovascularly treated patients with critical limb ischemia

INTRODUCTION

Hypolysible fibrin clots composed of tightly packed fibers characterize patients with peripheral artery disease (PAD) especially those with critical limb ischemia (CLI). Little is known about the impact of a prothrombotic clot phenotype on restenosis following endovascular revascularization in CLI. The goal of this study was to compare fibrin clot properties and their determinants in CLI patients with restenosis after endovascular treatment (ET) and those free of this complication.

METHODS

85 patients with CLI and restenosis within 1 year after ET on optimal pharmacotherapy and 47 PAD control patients without restenosis were included into the study. Plasma fibrin clot permeability (Ks, a measure of the average pore size in the fibrin network) and clot lysis time (CLT) with its potential determinants were determined. During follow-up, the composite endpoint including re-intervention, amputation and death was assessed.

RESULTS

Compared with the control group, patients with restenosis had reduced Ks (- 9.5%, p < 0.001), prolonged CLT (+ 12.4%, p = 0.003), higher thrombin generation (+ 7.9%, p < 0.001) and elevated von Willebrand factor (vWF) antigen (+ 14.2%, p < 0.001). During a 24 months follow-up the composite endpoint occurred in 54 CLI patients with restenosis (63.5%) and nine control patients (19.1%, p < 0.001) with no association with baseline Ks and CLT.

CONCLUSION

The increased thrombin formation and unfavorable fibrin clot properties occur in patients with CLI who experienced restenosis despite optimal endovascular and pharmacological therapy.

Lower extremity critical limb ischemia: A review of clinical features and management

Lower extremity critical limb ischemia (CLI) represents symptoms related to end-stage atherosclerotic peripheral arterial disease manifested by rest pain and tissue loss. It is associated with increased risk of limb amputation and cardiovascular-related mortality. The prevalence and cost of CLI are expected to increase with both the aging of the U.S. population and continued influence of smoking and diabetes. Treatments encompass measures to reduce cardiovascular risk and preserve limb viability. Despite increasing popularity of endovascular modalities, revascularization with either surgical bypass or endovascular intervention is the cornerstone of therapy. Adequate Level I data to guide decisions regarding optimal strategies to treat CLI, particularly in patients who are candidates for both open and percutaneous approaches, are currently lacking. Ongoing randomized controlled trials aim to resolve the clinical equipoise.

On the Cutting Edge: Wound Care for the Endovascular Specialist

Clinical outcomes in patients with critical limb ischemia (CLI) depend not only on endovascular restoration of macrovascular blood flow but also on aggressive periprocedural wound care. Education about this area of CLI therapy is essential not only to maximize the benefits of endovascular therapy but also to facilitate participation in the multidisciplinary care crucial to attaining limb salvage. In this article, we review the advances in wound care products and therapies that have granted the wound care specialist the ability to heal previously nonhealing wounds. We provide a primer on the basic science behind wound healing and the pathogenesis of ischemic wounds, familiarize the reader with methods of tissue viability assessment, and provide an overview of wound debridement techniques, dressings, hyperbaric therapy, and tissue offloading devices. Lastly, we explore emerging technology on the horizons of wound care.

Current concepts for the evaluation and management of diabetic foot ulcers

The lifetime risk for diabetic patients to develop a diabetic foot ulcer (DFU) is 25%. In these patients, the risk of amputation is increased and the outcome deteriorates.More than 50% of non-traumatic lower-extremity amputations are related to DFU infections and 85% of all lower-extremity amputations in patients with diabetes are preceded by an ulcer; up to 70% of diabetic patients with a DFU-related amputation die within five years of their amputation.Optimal management of patients with DFUs must include clinical awareness, adequate blood glucose control, periodic foot inspection, custom therapeutic footwear, off-loading in high-risk patients, local wound care, diagnosis and control of osteomyelitis and ischaemia. Cite this article: EFORT Open Rev 2018;3:513-525. DOI: 10.1302/2058-5241.3.180010.

Efficacy Outcomes of Endovascular Versus Surgical Revascularization in Critical Limb Ischemia: Results From a Prospective Cohort Study

Data on efficacy outcomes of endovascular versus surgical revascularization in patients with critical limb ischemia (CLI) in contemporary practice are limited. In this prospective cohort study, 353 consecutive patients with CLI were enrolled and allocated to endovascular (PTA [percutaneous transluminal angioplasty]), surgical (SURG), or no revascularization (No REVASC) after interdisciplinary consensus. Outcome measures were sustained primary clinical success (sPCS; survival without major amputation, repeated target extremity revascularization, and freedom from CLI), limb salvage, and amputation-free survival. Propensity-matched Kaplan-Meier analyses and stratified log-rank tests were performed. The PTA, SURG, and No REVASC groups consisted of 264, 62, and 27 patients, respectively. Compared to SURG patients, PTA patients were significantly older, had more risk factors, and more often had ischemic lesions. Propensity score-adjusted analyses showed no significant differences: sPCS was 51.3%/52.2%, limb salvage rate 91.5%/93.7%, and major amputation-free survival 90.5%/87.2% at 12 months for PTA and SURG, respectively. Amputation-free survival for the No REVASC group was 69% at 12 months. In conclusion, endovascular and surgical revascularization in CLI has comparable efficacy outcomes after 12 months. Contemporary overall outcome of patients with CLI is considerably better compared to earlier studies.

Heterogeneity of Ankle-Brachial Indices in Patients Undergoing Revascularization for Critical Limb Ischemia

OBJECTIVES

This study sought to describe the distribution of pre-intervention treated-limb ankle-brachial indices (ABIs) among patients with critical limb ischemia (CLI) undergoing percutaneous vascular intervention (PVI) or surgical revascularization (SR).

BACKGROUND

CLI is diagnosed by the presence of rest pain, tissue ulceration, or gangrene due to chronic arterial insufficiency. It is unclear what fraction of patients with suspected CLI have severe peripheral artery disease (PAD) on noninvasive functional testing.

METHODS

The study included patients who underwent lower extremity revascularization for CLI in a multicenter registry in Michigan from January 2012 through June 2015. ABIs were classified as normal (ABI: 0.91 to 1.40), mild-moderate (ABI: 0.41 to 0.90), and severe (ABI: ≤0.40). Pre- and post-intervention Peripheral Artery Questionnaire summary scores were assessed in a subset of patients.

RESULTS

Among 10,756 patients with signs or symptoms of CLI, 9,113 (84.7%) underwent PVI and 1,643 (15.3%) underwent SR. ABIs were recorded in 4,972 (54.6%) PVI and 1,012 (61.6%) SR patients. Patients undergoing PVI had higher ABIs than those undergoing SR, with substantial variation in both groups (PVI: 0.72 ± 0.29 vs. SR: 0.61 ± 0.29; p < 0.001). Nearly a quarter of patients with compressible arteries had normal ABIs (24.0%), whereas severe PAD was uncommon (16.5%). A significant improvement in Peripheral Artery Questionnaire scores was noted after intervention across all ABI categories.

CONCLUSIONS

Among patients undergoing revascularization for CLI in contemporary practice, the authors found substantial heterogeneity in pre-intervention ABIs. The disconnect between ABI results and clinical diagnosis calls into question the utility of ABIs in this population and suggests the need for standardization of functional PAD testing.

Decision-Making in Critical Limb Ischemia: A Markov Simulation

BACKGROUND

Critical limb ischemia (CLI) is a feared complication of peripheral vascular disease that often requires surgical management and may require amputation of the affected limb. We developed a decision model to inform clinical management for a 63-year-old woman with CLI and multiple medical comorbidities, including advanced heart failure and diabetes.

METHODS

We developed a Markov decision model to evaluate 4 strategies: amputation, surgical bypass, endovascular therapy (e.g. stent or revascularization), and medical management. We measured the impact of parameter uncertainty using 1-way, 2-way, and multiway sensitivity analyses.

RESULTS

In the base case, endovascular therapy yielded similar discounted quality-adjusted life months (26.50 QALMs) compared with surgical bypass (26.34 QALMs). Both endovascular and surgical therapies were superior to amputation (18.83 QALMs) and medical management (11.08 QALMs). This finding was robust to a wide range of periprocedural mortality weights and was most sensitive to long-term mortality associated with endovascular and surgical therapies. Utility weights were not stratified by patient comorbidities; nonetheless, our conclusion was robust to a range of utility weight values.

CONCLUSIONS

For a patient with CLI, endovascular therapy and surgical bypass provided comparable clinical outcomes. However, this finding was sensitive to long-term mortality rates associated with each procedure. Both endovascular and surgical therapies were superior to amputation or medical management in a range of scenarios.

Epidemiology of Peripheral Arterial Disease and Critical Limb Ischemia

With a rise in the aging popluation, the prevalence of peripheral arterial disease (PAD) is markedly increasing. The overall disease prevalence of PAD is in the range of 3%-10%, which increases to 15%-20% in persons older than 70 years of age. Given this upward trend in disease prevalence, the economic and societal burden of PAD would be considerable. The subgroup of patients who develop critical limb ischemia (CLI) represents the most challenging population to manage medically, surgically, and endovascularly. Patients with symptomatic PAD and CLI have an increased risk for death and cardiovascular events, especially in those with CLI who carry with them a substantial risk of limb loss. Advances in medical, surgical, and endovascular techniques have shown excellent outcomes in the treatment of these patients, however the optimal management paradigm has not been elucidated. This article reviews the classification and epidemiology, risk factors, natural history, and health care costs associated with PAD and CLI.

Determining End Points for Critical Limb Ischemia Interventions

Critical limb ischemia is a condition that has increased in prevalence and carries a high degree of morbidity. Although endovascular therapy for treatment of patients with critical limb ischemia has undergone significant advances with improved outcomes over the past decade, these patients often have multilevel disease, and it may take weeks or months for ulceration healing. For this reason, the acceptable therapeutic end points during and immediately following revascularization remain somewhat obscure. There are multiple tools available to guide the treating vascular specialist in this regard. Establishment of in-line flow to the foot and the angiosome containing the ulceration, appearance of a "wound blush," restoration of pulses, and bleeding at the ulcer site are basic tenets intraprocedurally. Postprocedural noninvasive testing including the ankle-brachial and toe-brachial indices, segmental pressure measurements, pulse volume recordings, transcutaneous oxygen tension, skin perfusion pressures (SPPs), and toe pressures all play a role in determining the likelihood of clinical improvement. Newer technologies such as two-dimensional (2D) perfusion angiography, fluorescence angiography, and tissue oxygen saturation mapping may allow better real-time assessment of flow restoration. In combination with close clinical follow-up and wound care, these tools provide treating physicians with a better grasp of the necessary end points to optimize patients for clinical improvement.