Functional ability in patients with critical limb ischaemia is unaffected by successful revascularisation

Post-operative transfusion is associated with infrainguinal bypass graft failure: contemporary Australian tertiary centre experience

BACKGROUNDS

Peripheral arterial disease (PAD) is an increasingly prevalent and highly morbid pathology affecting the older population. Infra-inguinal bypass (IIB) surgery remains a robust revascularization option in these patients. This study aimed to identify modifiable predictors associated with graft patency and functional outcomes in contemporary Australian vascular surgical practice.

METHODS

A retrospective analysis of patients undergoing IIB between 2010 and 2020 at a tertiary vascular surgery centre in Australia was performed. Data regarding patient demographics, co-morbidities, pre-operative investigations, bypass characteristics, and discharge outcomes were collected. Surveillance ultrasound scans were reviewed to gain information on graft patency and compliance up to 2 years post-operatively. The primary outcome was graft failure. Secondary outcomes were mobility status and amputation-free survival at 1 year.

RESULTS

A total of 239 IIBs were performed on 207 patients during the 10-year period. Significant predictors for primary graft occlusion included regional referral (P < 0.01), low pre-operative haemoglobin level (P < 0.01), post-operative transfusion requirement (P = 0.02), use of prosthetic conduit (P < 0.01) and non-compliance to ultrasound surveillance (P < 0.01). Patients with a thrombosed graft were 2.4 times more likely to experience deterioration in mobility status (P < 0.01) and 8.6 times more likely to have major limb amputation or death at 1 year. The amputation-free survival was 88.3% at 1 year.

CONCLUSION

Optimization of pre-operative haemoglobin level for IIB should be advocated in clinical practice in order to reduce the risk of graft failure, deterioration in ambulatory function, major limb amputation and mortality.

One year clinical outcomes of Rutherford 6 chronic limb threatening ischemia patients undergoing lower limb endovascular revascularisation from Singapore

BACKGROUND

Percutaneous transluminal angioplasty (PTA) is widely used as a first-line revascularisation option in patients with chronic limb threatening ischemia (CLTI). This study aimed to evaluate the short-term endovascular revascularisation treatment outcomes of a cohort of Rutherford 6 (R6) CLTI patients, from a multi-ethnic Asian population in Singapore. Patients with R6 CLTI who underwent endovascular revascularisation from June 2019 to February 2020 at Singapore General Hospital, a tertiary vascular centre in Singapore, were included and followed up for one year. Primary outcome measures included number and type of reinterventions required, 3-, 6- and 12-month mortality, 6- and 12-month amputation free survival (AFS), wound healing success and changes in Rutherford staging after 3, 6 and 12 months.

RESULTS

Two hundred fifty-five procedures were performed on 86 patients, of whom 78 (90.7%) were diabetics, 54 (62.8%) had coronary artery disease (CAD) and 54 (62.8%) had chronic kidney disease (CKD). 42 patients (48.8%) required reintervention within 6 months. Multivariate analysis revealed that the presence of CAD was a significant independent predictor for reintervention. Mortality was 15.1%, 20.9% and 33.7% at 3, 6 and 12 months respectively. AFS was 64.0% and 49.4% at 6 and 12 months. Inability to ambulate, congestive heart failure (CHF), dysrhythmia and CKD were significant independent predictors of lower 12-month AFS.

CONCLUSIONS

PTA for R6 CLTI patients was associated with relatively high mortality and reintervention rates at one year. CAD was an independent predictor of reintervention. More research is required to help risk stratify which CLTI patients would benefit from an endovascular-first approach versus conservative treatment or an immediate major lower extremity amputation policy.

Associations of Clinical Frailty with Severity of Limb Threat and Outcomes in Chronic Limb-threatening Ischaemia

OBJECTIVE

Investigate the relationship of frailty and severity of chronic limb-threatening ischaemia (CLTI), and their comparative associations with one-year outcomes, in patients presenting to a vascular limb salvage (VaLS) clinic.

METHODS

This retrospective cohort study utilised data collected from a prospectively maintained VaLS clinic database. Patients aged ≥50 presenting to the VaLS clinic with CLTI between February 2018 and April 2019 were included. Frailty was measured using the Clinical Frailty Scale (CFS) and limb threat severity by the Wound, Ischaemia, and foot Infection (WIfI) score. Excessive polypharmacy was defined as ≥10 medications. Anticholinergic burden (ACB) score and Charlson comorbidity index (CCI) were calculated for all patients. The primary outcome measure was a composite endpoint of death or amputation at one-year. Associations with outcome were assessed using Cox regression and reported as hazards ratios (HR) with 95% confidence intervals (CI).

RESULTS

A total of 198 patients were included, with CFS scores available for 190 patients. 98 patients (52%) were frail (CFS ≥5). 127 patients (67%) initially underwent endovascular revascularisation. Excessive polypharmacy was common (55 patients; 28%). Frailty was associated with increased WIfI stage (P = 0.025) as well as age, female sex, CCI score, number of medications, excessive polypharmacy but not ACB score. Frail patients were more frequently managed non-operatively (P = 0.017). Frailty (HR 1.91; 95% CI 1.09, 3.34; P = 0.024) and WIfI stage 4 (HR 3.29; 95%CI 1.23, 8.80; P = 0.018) were associated with death or amputation on univariable analysis. WIfI stage 4 (HR 2.80; 95%CI 1.04, 7.57; P = 0.042) and CCI score (HR 1.21; 95%CI 1.03, 1.41; P = 0.015), but not frailty (HR 1.25; 95%CI 0.67, 2.33; P = 0.474), were independently associated with death or amputation on multivariable analysis.

CONCLUSIONS

Frailty is highly prevalent among CLTI patients and related to severity of limb threat. The CFS may be a useful adjunct to patient risk assessment in CLTI.

Two-year Outcome of Quality of Life and Health Status for the Elderly with Chronic Limb-threatening Ischemia

Purpose

In elderly patients with chronic limb-threatening ischemia (CLTI), there is little scientific understanding of the long-term changes of quality of life (QoL) and health status (HS) after treatment. The primary goal of this study was to provide long-term QoL and HS results for elderly CLTI patients after therapy. Treatments consisted of endovascular revascularization, surgical revascularization, or conservative treatment. Furthermore, the aim of this study was to identify the distinctive trajectories of QoL and HS.

Patients and Methods

CLTI patients aged ≥70 years were included in a prospective observational cohort study with a two-year follow-up. The WHOQOL-BREF was used to asses QoL. The 12-Item Short Form Health Survey was used to measure HS. The QoL and HS scores were compared to the scores in the general elderly Dutch population. Latent class trajectory analysis was used.

Results

A total of 195 patients were included in this study. After two years, in all treatment groups patients showed significantly higher physical QoL score compared to baseline and there was no significant difference with the corresponding values in the elderly Dutch population. In the latent class trajectory analysis, there were no overlapping risk factors for poorer QoL or HS.

Conclusion

This study shows that QoL levels in surviving elderly CLTI patients in the long-term do not differ from the corresponding values for elderly in the general population. There were no disparities in sociodemographic, clinical and treatment characteristics associated with poorer QoL and HS. This study was carried out to encourage further analysis of the influence of biopsychosocial characteristics on QoL and HS in elderly CLTI patients.

Arterial Reconstruction for Patients with Chronic Limb Ischemia Improves Ambulatory Function and Health-related Quality of Life

BACKGROUND

Arterial reconstruction (AR) for limb ischemia may improve ambulatory function (AF) and health-related quality of life (HR-QoL). However, the efficacy of AR in terms of HR-QoL varies in studies, probably because of cohort differences in disease severity, hemodynamic outcomes, and observation duration. We assessed HR-QoL for patients with various severities of ischemia in a 3-year observational study.

METHODS

We conducted a single-center 3-year observational study using Short Form 36 in patients with chronic limb ischemia. Between 2001 and 2009, 515 consecutive patients had AR, and 330 who underwent elective AR consented to the study. Of the 330 patients (claudicants 49%, critical limb ischemia [CLI] 51%), 307 underwent bypass and 23 endovascular therapy. Postal questionnaires were sent after AR, and 8 domains, the physical and mental component summary (PCS and MCS) scores, and the patient-reported AF were compared, and negative predictors were identified.

RESULTS

Overall, the MCS was minimally affected, but AF and the PCS were impaired. After AR, these measures were significantly improved, and maximum recovery was attained at 6 months. In subgroup analysis, significant predictors of a negative impact on postoperative PCS included age ≥80, CLI, physical aftereffects of stroke (PAS), and previous major amputation (PMA). Of these, PMA was associated with the lowest PCS score, followed by PAS; for these patients, AR contributed minimally to HR-QoL recovery. PCS scores of claudicants attained a maximum value at 6 months; however, PCS scores of CLI patients were significantly lower than intermittent claudication patients (P < 0.0001), and patients with major tissue loss required 2 years to attain maximum PCS recovery.

CONCLUSIONS

This 3-year observational study verified the efficacy of AR in improving AF and HR-QoL. Age ≥80, CLI, PAS, and PMA were definitive predictors, and for patients with the latter 2, AR contributed minimally to improving HR-QoL.

Impact of Low Activity of Daily Living on the Prognosis of Patients with Critical Limb Ischemia and Sarcopenia

BACKGROUND

We aimed to investigate the impact of low activity of daily living (ADL) on the long-term outcomes after infrainguinal bypass surgery in patients with critical limb ischemia (CLI) and sarcopenia.

METHODS

In this multicenter retrospective cohort study, 110 patients with CLI who underwent infrainguinal bypass between April 2011 and September 2016 were divided into 4 groups according to the presence or absence of sarcopenia before surgery and ADL at discharge (Normal group: absence of sarcopenia and normal ADL [Barthel Index ≥60]; Low ADL alone group: absence of sarcopenia and abnormal ADL [Barthel Index <60]; Sarcopenia alone group: presence of sarcopenia and normal ADL; Sarcopenia and low ADL group: presence of sarcopenia and abnormal ADL). Three-year overall survival (OS) and amputation-free survival (AFS) were compared among the 4 groups using the Kaplan-Meier method, and Cox proportional hazards models were used to assess the unadjusted and adjusted associations between patient characteristics and 3-year OS and AFS.

RESULTS

The Sarcopenia and low ADL group was significantly inferior to the other 3 groups in 3-year OS (versus Normal group, P < 0.001; versus Low ADL alone group, P = 0.005; versus Sarcopenia alone group, P = 0.022) and was significantly inferior to the Normal group and Sarcopenia alone group in 3-year AFS (P < 0.001 and P = 0.027, respectively). In the multivariable analysis, after adjustment for age, sex, ischemic heart disease, and hemodialysis, the presence of both sarcopenia and low ADL was a significant predictor of 3-year OS (hazard ratio [HR] 5.99, 95% confidence interval [CI] 1.92-18.69, P = 0.002) and AFS (HR 3.63, 95% CI 1.27-10.39, P = 0.016).

CONCLUSIONS

Low ADL at discharge was a significant predictor of 3-year OS and AFS in patients with CLI and sarcopenia, while either sarcopenia alone or low ADL alone did not significantly affect outcomes.

Important differences between quality of life and health status in elderly patients suffering from critical limb ischemia

Introduction

Critical limb ischemia (CLI) patients are often of advanced age with reduced health status (HS) and quality of life (QoL) at baseline. Physical health is considered as the most affected domain due to reduced mobility and ischemic pain. QoL and HS are often used interchangeably in the current literature. HS refers to objectively perceived physical, psychological, and social functioning and in assessing QoL, change is measured subjectively and can only be determined by the individual since it concerns patients’ evaluation of their functioning. It is important to distinguish between QoL and HS, especially in the concept of shared decision-making when the opinion of the patient is key. Goal of this study was to examine and compare QoL and HS in elderly CLI patients in relation to the used therapy, with a special interest in conservatively treated patients.

Methods

Patients suffering from CLI and ≥70 years old were included in a prospective study with a follow-up period of 1 year. Patients were divided into three groups; endovascular revascularization, surgical revascularization, and conservative therapy. The WHOQoL-Bref was used to determine QoL, and the 12-Item Short Form Health Survey was used to evaluate HS at baseline, 5–7 days, 6 weeks, 6 months, and 1 year.

Results

Physical QoL of endovascularly and surgically treated patients showed immediate significant improvement during follow-up in contrast to delayed increased physical HS at 6 weeks and 6 months (P<0.001). Conservatively treated patients showed significantly improved physical QoL at 6 and 12 months (P=0.02) in contrast to no significant improvement in physical HS.

Conclusion

This study demonstrates that QoL and HS are indeed not identical concepts and that differentiating between these two concepts could influence the choice of treatment in elderly CLI patients. Discriminating between QoL and HS is, therefore, of major importance for clinical practice, especially to achieve shared decision-making.

Toll-like receptors 2 and 6 mediate apoptosis and inflammation in ischemic skeletal myotubes

Critical limb ischemia (CLI) is associated with skeletal muscle damage. However, the pathophysiology of the muscle damage is poorly understood. Toll-like receptors (TLR) have been attributed to play a role in ischemia-induced tissue damage but their role in skeletal muscle damage in CLI is unknown. TLR2 and TLR6 expression was found to be upregulated in skeletal muscle of patients with CLI. In vitro, ischemia led to upregulation of TLR2 and TLR6 by myotubes, and activation of the downstream TLR signaling pathway. Ischemia-induced activation of the TLR signaling pathway led to secretion of the pro-inflammatory cytokine interleukin-6 and muscle apoptosis, which were abrogated by neutralising TLR2 and TLR6 antibodies. Our study demonstrates that TLR2 and TLR6 are upregulated in ischemic muscle and play a role in ischemia-induced muscle damage. Thus, manipulating the TLR pathway locally may be of potential therapeutic benefit.

Quality of Life and not Health Status Improves After Major Amputation in the Elderly Critical Limb Ischaemia Patient

OBJECTIVES

A patient-oriented appraisal of treatment has become extremely important, particularly in elderly patients with critical limb ischaemia (CLI). Quality of life (QoL) is an important patient-reported outcome in vascular surgery. Frequently, the physical domain of QoL questionnaires represents an 'objective' evaluation of performing activities, which is expected to be impaired after major limb amputation. However, an objective appraisal of physical function is an assessment of health status (HS) and not of QoL. Little is known about the subjective appraisal of physical health (QoL). The goal of this study was to evaluate, prospectively, QoL in relation to HS in elderly CLI patients undergoing major limb amputation.

METHODS

Patients suffering from CLI aged 70 years or older were included in a prospective observational cohort study with a follow-up period of 1 year. Patients were divided according to having had an amputation or not. The World Health Organization Quality Of Life-BREF (WHOQOL-BREF) was used to asses QoL. The 12-Item Short Form Health Survey (SF-12) was used to measure HS. These self-reported questionnaires were completed five times during follow-up.

RESULTS

Two-hundred patients were included of whom 46 underwent a major limb amputation within one year. Amputees had a statistically significant improvement of their physical QoL after six months (14.0 vs. 9.0 (95% CI -7.84;-1.45),p = 0.005) and after a one-year follow-up (14.0 vs. 9.0 (95% CI -9.58;-1.46),p = 0.008). They did not however show any statistically significant difference in HS. For non-amputees, both physical QoL and HS improved. An instant statistically significant improvement of the physical QoL appeared 1 week after inclusion (12.0 vs. 10.9 (95% CI -1.57;-0.63),p<0.001). Similarly, statistically significant improvement in the physical HS first occurred at 1 week follow-up (29.0 vs. 28.9 (95% CI -5.78; -2.23),p = 0.003).

CONCLUSIONS

There is a clear difference between patients' functioning (HS) and the patients' appraisal of functioning (QoL). In elderly CLI patients, this study clearly suggests a discrepancy between the physical QoL (WHOQOL-BREF) and HS (SF-12) measurements in vascular amputees. This raises the question, which outcome measurement is the most relevant for elderly CLI patients. Individual treatment goals should be kept in mind when assessing the HS or QoL outcome of patients undergoing hospital care. With respect to shared decision making, distinctive and subjective QoL questionnaires, like the WHOQOL-BREF, provide a very important outcome measurement and should be used in future research.

Serum-derived extracellular vesicles (EVs) impact on vascular remodeling and prevent muscle damage in acute hind limb ischemia

Serum is an abundant and accessible source of circulating extracellular vesicles (EVs). Serum-EV (sEV) pro-angiogenic capability and mechanisms are herein analyzed using an in vitro assay which predicts sEV angiogenic potential in vivo. Effective sEVs (e-sEVs) also improved vascular remodeling and prevented muscle damage in a mouse model of acute hind limb ischemia. e-sEV angiogenic proteomic and transcriptomic analyses show a positive correlation with matrix-metalloproteinase activation and extracellular matrix organization, cytokine and chemokine signaling pathways, Insulin-like Growth Factor and platelet pathways, and Vascular Endothelial Growth Factor signaling. A discrete gene signature, which highlights differences in e-sEV and ineffective-EV biological activity, was identified using gene ontology (GO) functional analysis. An enrichment of genes associated with the Transforming Growth Factor beta 1 (TGFβ1) signaling cascade is associated with e-sEV administration but not with ineffective-EVs. Chromatin immunoprecipitation analysis on the inhibitor of DNA binding I (ID1) promoter region, and the knock-down of small mother against decapentaplegic (SMAD)1–5 proteins confirmed GO functional analyses. This study demonstrates sEV pro-angiogenic activity, validates a simple, sEV pro-angiogenic assay which predicts their biological activity in vivo, and identifies the TGFβ1 cascade as a relevant mediator. We propose serum as a readily available source of EVs for therapeutic purposes.

Validation of the Risk Score of the Mortality and Lower Limb Loss Considering Ambulatory Status after Surgical Revascularization in Maintaining Patients with Dialysis

Surgical revascularization is performed to preserve limb and to maintain functional status of patients with critical limb ischemia (CLI). The PREVENT III risk score helps to predict the postoperative course of CLI. However, this score is not available to estimate the risk of amputation or death properly in patients with hemodialysis (HD) and tissue loss (HD: 4 points, Tissue loss: 3 points), because they are classified as a high-risk group. Therefore, we investigated 213 patients with revascularized HD for CLI and proposed prognosis amputation or death for patients with HD risk score (PAD for HD risk score). PAD for HD risk score (non-ambulation: 3 points, ulcer/gangrene: 2 points, GNRI<92: 2 points, CRP>0.3 mg/dl: 1 point, Age≥75: 1 point) is more accurate for the prediction of amputation or death than the PREVENT III risk score (area under the curve [AUC]: 0.79 [95% confidence interval: CI: 0.71-0.87], p<0.01 vs. AUC: 0.63 [95%CI: 0.56-0.71]). The patients were stratified into three groups by total score in ascending order. The rate of 1-year amputation-free survival and independent ambulatory status were significantly different among three groups. PAD for HD risk score is useful for rehabilitation planning in patients with HD and CLI. (This is a translation of J Jpn Coll Angiol 2016; 56: 85-91.).

TLR-4 and CD14 Genotypes and Soluble CD14: Could They Predispose to Coronary Atherosclerosis?

Background: Inflammatory mechanisms are key to the pathogenesis of atherosclerosis. Functional polymorphisms of TLR-4, Asp299Gly and Thr399Ile, CD14 promoter area C260T polymorphism and plasma levels of soluble CD14 are studied in subjects with Coronary Artery Disease (CAD). Methods: DNA was obtained from 100 human paraffin-embedded aortic specimens, from cadavers with known coronary atheromatosis (Group A) and 100 blood samples from patients with CAD, as detected by cardiac Multi-Detector-row-Computed-Tomography (MDCT) (Group B). Our control group consisted of 100 healthy individuals (Group C). Genotyping was performed by Restriction Fragment Length Polymorphism-Polymerase Chain Reaction (RFLP-PCR). Plasma levels of sCD14 were measured with ELISA. Results: For TLR-4 Asp299Gly and Thr399Ile polymorphisms, no statistically significant differences were observed. Regarding the C260T polymorphism, frequencies of T allele were significantly higher in the control group compared to the case group (p = 0.05). The Odds Ratio (OR) showed statistically significant association of TT genotype with healthy individuals (OR 0.25, 95% Confidence Interval CI 0.10–0.62, p = 0.0017). Plasma levels of sCD14 in patients with CAD (mean value = 1.35 μg/mL) were reduced when compared to reference value. Conclusions: The studied polymorphisms ofTLR-4 showed no association with CAD. Conversely, the functional polymorphism of CD14 has a statistically significant difference in expression between healthy and affected by CAD individuals.

Anthropometric and Quality-of-Life Parameters in Acute Intermittent Porphyria Patients

The porphyrias are a group of rare metabolic disorders. The incidence and prevalence are low because the acute intermittent porphyria (AIP) is rare. Our aim was to assess the use of anthropometric and quality-of-life parameters in porphyric patients in order to identify predictor factors that might help in characterizing AIP patients.Sixteen AIP patients from Murcia (Spain) were recruited from local health centers in 2008 and 2009. A control group of 16 healthy people was established. Body composition was assessed by bioelectrical impedance analysis (BIA) and anthropometric measurements: body weight; height; knee-heel height; waist, hip, upper arm and calf circumferences (CCs); biacromion and biiliac diameters; bicondylar and biepicondylar width; and triceps, subscapular, supraspinale, and calf skinfold thickness. Anthropometric indicators were obtained from anthropometric measurements. A quality-of-life evaluation was carried out using the EuroQol-5D (EQ-5D) questionnaire and Barthel and Katz indexes. Significant differences in means were tested by unpaired Student t test. Group differences in anthropometric measurements were tested with a 2-way analysis of variance (group × condition: age group, overweight, and adiposity degree). Relative frequencies were obtained for noncontinuous variables. Significant differences in prevalence were calculated by means of χ.AIP patients showed statistically significant differences in terms of knee-heel height, biiliac diameter, CC, triceps skinfold thickness, BIA, ponderal index, endomorphy, and ectomorphy. Only 1 quality-of-life indicator, visual analog scale, in the EQ-5D questionnaire showed significant differences between porphyric and control groups.Some anthropometric parameters and the EQ-5D questionnaire could be used to appreciate the presence or follow the evolution of the disease in AIP patients.

Validation of the Guy's scoring system in patient selection for femoro-distal bypass grafting to a single calf or pedal artery

OBJECTIVES

First external validation of a preoperative scoring system (Guy's) in patient selection for femoro-distal bypass grafting to single calf or pedal artery in critical limb ischemia (Fontaine III & IV/Rutherford grade IV, V & VI).

MATERIAL AND METHODS

A prospective study of 76 (n = 76) consecutive femoro-crural/pedal bypass grafts on 72 individuals (n = 72) from 2008 to 2011 with 36 months mean follow-up was performed. All cases were scored against a previously designed and published scoring system (ranging from 0 to 10) based on: inflow, outflow, graft material, flow type, patent pedal vessels and diabetes mellitus.

RESULTS

Preoperative score of 0-4 (n = 37) demonstrated the primary patency of 27% at 10.3 months. This value for intermediate group 5-7 (n = 34) was 70.6% at 18.9 months. The high-score group 8-10 (n = 4) showed the longest primary patency (80%) at 27.3 months. Kaplan-Meier survival analysis exhibited a consistent and significant difference in primary assisted, secondary patency and overall limb/foot salvage amongst all individual scoring groups (p < 0.001).

CONCLUSION

This study validates and complements the Guy's scoring system and provides a platform for the identification of critical limb ischemia patients in whom the result of femoro-crural/distal bypass grafting is so poor that primary amputation may be both clinically and economically more justified.

Unacylated ghrelin induces oxidative stress resistance in a glucose intolerance and peripheral artery disease mouse model by restoring endothelial cell miR-126 expression

Reactive oxygen species (ROS) are crucial in long-term diabetes complications, including peripheral artery disease (PAD). In this study, we have investigated the potential clinical impact of unacylated ghrelin (UnAG) in a glucose intolerance and PAD mouse model. We demonstrate that UnAG is able to protect skeletal muscle and endothelial cells (ECs) from ROS imbalance in hind limb ischemia-subjected ob/ob mice. This effect translates into reductions in hind limb functional impairment. We show that UnAG rescues sirtuin 1 (SIRT1) activity and superoxide dismutase-2 (SOD-2) expression in ECs. This leads to SIRT1-mediated p53 and histone 3 lysate 56 deacetylation and results in reduced EC senescence in vivo. We demonstrate, using small interfering RNA technology, that SIRT1 is also crucial for SOD-2 expression. UnAG also renews micro-RNA (miR)-126 expression, resulting in the posttranscriptional regulation of vascular cell adhesion molecule 1 expression and a reduced number of infiltrating inflammatory cells in vivo. Loss-of-function experiments that target miR-126 demonstrate that miR-126 also controls SIRT1 and SOD-2 expression, thus confirming its role in driving UnAG-mediated EC protection against ROS imbalance. These results indicate that UnAG protects vessels from ROS imbalance in ob/ob mice by rescuing miR-126 expression, thus emphasizing its potential clinical impact in avoiding limb loss in PAD.

The effect of genetic polymorphisms of TLR2 and TLR4 in Turkish patients with coronary artery disease

Coronary artery disease (CAD), being a multifactorial disease process, has been suggested to be associated by the interaction of both environmental and genetic risk factors. Toll-like receptors (TLRs) are related to the receptors of the innate immune system which serves as the recognition of the conserved pathogen motifs and the activation of the signals that stimulate inflammatory genes. In this study, we investigated the relationship between the polymorphisms in the TLR2-Arg753Gly, TLR4-Asp299Gly and Thr399Ile gene and CAD. The study population consisted of 300 patients (149 men, 151 women) with angiographically documented CAD. The polymorphisms were genotyped by real time PCR. No association between TLR2-Arg677Trp or TLR4-Asp299Gly and -Thr399Ile gene polymorphisms and the presence or the severity of CAD was observed. On the other hand, the TLR2-Arg753Arg genotype seemed to have a protective effect against development of CAD (OR=0.17; 95% CI=0.04-0.83). Our findings suggest that TLR2-Arg753Gly polymorphism is associated with CAD susceptibility in Turkish patients.

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

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

Objective measurement of lower extremity function and quality of life after surgical revascularization for critical lower extremity ischemia

BACKGROUND

Outcomes of revascularization for critical limb ischemia (CLI) have historically been patency, limb salvage, and survival. Functional status and quality of life have not been well described. This study used functional and quality of life assessments to measure patient-centered outcomes after revascularization for CLI.

METHODS

The study observed 18 patients (age, 65 ± 11 years) prospectively before and after lower extremity bypass for CLI. Patients completed the Short Physical Performance Battery, which measures walking speed, leg strength, and balance, as well as performed a 6-minute walk, and calorie expenditure was measured by an accelerometer. Isometric muscle strength was assessed with the Muscle Function Evaluation chair (Metitur, Helsinki, Finland). Quality of life instruments included the 36-Item Short Form Health Survey and the Vascular Quality of Life questionnaire. Patients' preoperative status was compared with 4-month postoperative status.

RESULTS

Muscle Function Evaluation chair measurements of ipsilateral leg strength demonstrated a significant increase in knee flexion from 64 ± 62 N to 135 ± 133 N (P = .038) and nearly significant increase in knee extension from 120 ± 110 N to 186 ± 85 N (P = .062) and ankle plantar flexion from 178 ± 126 N to 267 ± 252 N (P = .078). In the contralateral leg, knee flexion increased from 71 ± 96 N to 149 ± 162 N (P = .028) and knee extension from 162 ± 112 N to 239 ± 158 N (P = .036). Absolute improvements were noted in 6-minute walk distance, daily calorie expenditure, and individual domains and overall Short Physical Performance Battery scores, and upper extremity strength decreased, although none were significant. The Vascular Quality of Life questionnaire captured significant improvement in all individual domains and overall score (P < .015). Significant improvement was noted only for bodily pain (P = .011) on the 36-Item Short Form Health Survey.

CONCLUSIONS

Despite lack of statistical improvement in most functional test results, revascularization for CLI results in improved patient-perceived leg function. Significant improvements in isometric muscle strength may explain the measured improvement in quality of life after revascularization for CLI.

Unacylated ghrelin promotes skeletal muscle regeneration following hindlimb ischemia via SOD-2-mediated miR-221/222 expression

Background

Surgical treatment of peripheral artery disease, even if successful, does not prevent reoccurrence. Under these conditions, increased oxidative stress is a crucial determinant of tissue damage. Given its reported antioxidant effects, we investigated the potential of unacylated‐ghrelin (UnAG) to reduce ischemia‐induced tissue damage in a mouse model of peripheral artery disease.

Methods and Results

We show that UnAG but not acylated ghrelin (AG) induces skeletal muscle regeneration in response to ischemia via canonical p38/mitogen‐actived protein kinase signaling UnAG protected against reactive oxygen species–induced cell injuries by inducing the expression of superoxide dismutase‐2 (SOD‐2) in satellite cells. This led to a reduced number of infiltrating CD68⁺ cells and was followed by induction of the myogenic process and a reduction in functional impairment. Moreover, we found that miR‐221/222, previously linked to muscle regeneration processes, was up‐regulated and negatively correlated with p57^Kip2 expression in UnAG‐treated mice. UnAG, unlike AG, promoted cell‐cycle entry in satellite cells of mice lacking the genes for ghrelin and its receptor (GHSR1a). UnAG‐induced p38/mitogen‐actived protein kinase phosphorylation, leading to activation of the myogenic process, was prevented in SOD‐2–depleted SCs. By siRNA technology, we also demonstrated that SOD‐2 is the antioxidant enzyme involved in the control of miR‐221/222–driven posttranscriptional p57^Kip2 regulation. Loss‐of‐function experiments targeting miR‐221/222 and local pre–miR‐221/222 injection in vivo confirmed a role for miR‐221/222 in driving skeletal muscle regeneration after ischemia.

Conclusions

These results indicate that UnAG‐induced skeletal muscle regeneration after ischemia depends on SOD‐2–induced miR‐221/222 expression and highlight its clinical potential for the treatment of reactive oxygen species–mediated skeletal muscle damage.

Changes in functional status after treatment of critical limb ischemia

OBJECTIVE

This study evaluated changes in functional status with the Academic Medical Center Linear Disability Score (ALDS) and in quality of life with the Vascular Quality of Life Questionnaire (VascuQol) in patients treated for critical limb ischemia (CLI).

METHODS

We conducted a prospective observational cohort study in a single academic center that included consecutive patients with CLI who presented between May 2007 and May 2010. The ALDS and VascuQol questionnaires were administered before treatment (baseline) and after treatment at 6 and 12 months of follow-up. Changes in functional status (ALDS) and quality of life (VascuQol) scores after 6 and 12 months, compared with baseline, were tested with the appropriate statistical tests, with significance set at P < .05.

RESULTS

The study included 150 patients, 96 (64%) were men, and mean (± standard deviation) age was 68.1 (± 12.4) years. The primary treatment was endovascular in 98 (65.3%), surgical in 36 (24%), conservative in 11 (7.3%), or a major amputation in five (3.3%). The ALDS was completed by 112 patients after 12 months. At that time, the median ALDS score had increased by 10 points (median, 83; range, 12-89; P = .001) in patients who achieved limb salvage, which corresponds with more difficult outdoor and indoor activities. In patients with a major amputation, the median ALDS score decreased by 14 points (median, 55; range, 16-89; P = .117) after 12 months, which corresponds with domestic activities only. VascuQol scores improved significantly in all separate domains for the limb salvage group (P < .001). All VascuQol scores, except for the activity and social domains, increased significantly after amputation.

CONCLUSIONS

Our study confirms the clinical validity of the ALDS in patients treated for CLI and shows that it is a valuable and sophisticated instrument to measure changes in functional status in these patients.

Potential role of erythropoietin receptors and ligands in attenuating apoptosis and inflammation in critical limb ischemia

OBJECTIVE

Managing critical limb ischemia (CLI) is challenging. Furthermore, ischemic myopathy prevents good functional outcome after revascularization. Hence, we have focused on limiting the tissue damage rather than angiogenesis, which has traditionally been the motivation to develop nonsurgical treatments for CLI. Erythropoietin (EPO) protects ischemic tissue, and this property may also benefit CLI. The objective of this study was to examine the expression of the tissue-protective EPO receptor complex (EPOR-CD131 [β-chain of interleukin (IL)-3/IL-5/granulocyte macrophage colony-stimulating factor receptor]) in skeletal muscle obtained from humans with CLI. Because native EPO is thrombogenic, the antiapoptotic and anti-inflammatory effects of a nonhematopoietic helix-B peptide of EPO (ARA 290) were investigated on ischemic myotubes in vitro.

METHODS

Tissue was obtained from gastrocnemius muscle of 12 patients undergoing amputation for CLI and from 12 patients without limb ischemia. The expression of EPOR and CD131 was demonstrated by immunohistochemistry and Western blot. A validated in vitro model of myotube ischemia was used in which mature C2C12 myotubes were cultured 6 to 12 hours in a depleted media and gas mixture (20% CO2 and 80% N2). The myotubes were pretreated with EPO or ARA 290 before exposure to simulated ischemia. Apoptosis and cell death were determined by cleaved caspase-3 assay and lactate dehydrogenase release assay. Enzyme-linked immunosorbent assay measured the inflammatory cytokines.

RESULTS

EPOR and CD131 were expressed and significantly upregulated in CLI (average optical density [OD] in Western blot [control vs CLI] EPOR, 0.05 U vs 0.1 U; CD131, 0.10 U vs 0.22 U; P < .01). There was colocalization of EPOR and CD131 in the sarcolemma (cell membrane) of the skeletal myofiber. There was no difference in the distribution of colocalization between the CLI and the normal muscle. The ischemic myotubes treated by ARA 290 in vitro had a significantly decreased number of apoptotic cells (ischemia vs ischemia plus ARA 290: 71.1% vs 55.1%; P < .01), cleaved caspase-3 (OD of ischemia vs ischemia plus ARA 290: 0.15 U vs 0.02 U; P < .01), lactate dehydrogenase release (ischemia vs ischemia plus ARA 290: 32.5 U/L vs 21.3 U/L; P < .01), and IL-6 release (OD at 450 nm, ischemia vs ischemia plus ARA 290: 0.18 vs 0.13; P < .01).

CONCLUSIONS

This study demonstrates the expression and the upregulation of EPOR and CD131 in CLI and also shows that EPOR and CDI are colocalized in the cell membrane of both ischemic and control muscle fiber. The in vitro experiments demonstrate that ARA 290 decreases inflammation and apoptosis of ischemic myotubes. ARA 290 may potentially be used as adjunctive treatment for CLI.

Chapter VI: Follow-up after revascularisation

Structured follow-up after revascularisation for chronic critical limb ischaemia (CLI) aims at sustained treatment success and continued best patient care. Thereby, efforts need to address three fundamental domains: (A) best medical therapy, both to protect the arterial reconstruction locally and to reduce atherosclerotic burden systemically; (B) surveillance of the arterial reconstruction; and (C) timely initiation of repeat interventions. As most CLI patients are elderly and frail, sustained resolution of CLI and preserved ambulatory capacity may decide over independent living and overall prognosis. Despite this importance, previous guidelines have largely ignored follow-up after CLI; arguably because of a striking lack of evidence and because of a widespread assumption that, in the context of CLI, efficacy of initial revascularisation will determine prognosis during the short remaining life expectancy. This chapter of the current CLI guidelines aims to challenge this disposition and to recommend evidentially best clinical practice by critically appraising available evidence in all of the above domains, including antiplatelet and antithrombotic therapy, clinical surveillance, use of duplex ultrasound, and indications for and preferred type of repeat interventions for failing and failed reconstructions. However, as corresponding studies are rarely performed among CLI patients specifically, evidence has to be consulted that derives from expanded patient populations. Therefore, most recommendations are based on extrapolations or subgroup analyses, which leads to an almost systematic degradation of their strength. Endovascular reconstruction and surgical bypass are considered separately, as are specific contexts such as diabetes or renal failure; and critical issues are highlighted throughout to inform future studies.

Toll-like receptors in ischaemia and its potential role in the pathophysiology of muscle damage in critical limb ischaemia

Toll-like receptors (TLRs) are key receptors of the innate immune system which are expressed on immune and nonimmune cells. They are activated by both pathogen-associated molecular patterns and endogenous ligands. Activation of TLRs culminates in the release of proinflammatory cytokines, chemokines, and apoptosis. Ischaemia and ischaemia/reperfusion (I/R) injury are associated with significant inflammation and tissue damage. There is emerging evidence to suggest that TLRs are involved in mediating ischaemia-induced damage in several organs. Critical limb ischaemia (CLI) is the most severe form of peripheral arterial disease (PAD) and is associated with skeletal muscle damage and tissue loss; however its pathophysiology is poorly understood. This paper will underline the evidence implicating TLRs in the pathophysiology of cerebral, renal, hepatic, myocardial, and skeletal muscle ischaemia and I/R injury and discuss preliminary data that alludes to the potential role of TLRs in the pathophysiology of skeletal muscle damage in CLI.