Risk factors for peripheral arterial disease among patients with chronic kidney disease

Chronic Kidney Disease and Risk of Mortality and Major Adverse Limb Events After Femoral Artery Endovascular Revascularization for Peripheral Artery Disease: The Boston Femoral Artery Endovascular Revascularization Outcomes (Boston FAROUT) Study

BACKGROUND

Chronic kidney disease (CKD) is associated with worse outcomes in peripheral artery disease (PAD). The impact of the severity of CKD on mortality and major adverse limb events (MALE) after endovascular revascularization of the superficial femoral artery (SFA) is unknown.

AIMS

To assess the relationship of increasing severity of CKD on the risk of mortality and MALE in patients after endovascular revascularization of the SFA.

METHODS

We followed a cohort of 202 patients (253 limbs) with SFA endovascular revascularization for claudication or chronic limb-threatening ischemia in two academic centers between 2003 and 2011. Patients were categorized into four Kidney Disease Improving Global Outcomes (KDIGO) categories of increasingly worse CKD based on estimated glomerular filtration rate (eGFR). The primary outcome was all-cause death. Secondary outcomes included cardiovascular death, noncardiovascular death, and MALE. The relationship between CKD severity and outcomes was assessed by hazard ratios (HR) and 95% confidence intervals (95%CI) from cause-specific multivariable Cox proportional hazards models and Fine-Gray competing risks analyses.

RESULTS

During a median follow-up of 9.3 years, there was a graded and increasing risk of all-cause, cardiovascular, and noncardiovascular mortality with worse eGFR (all tests of trend p < 0.001). The lowest eGFR category (< 45 mL/min/1.73 m²) was associated with the highest risk of all-cause mortality (HR = 5.0, 95% CI = 2.4, 10), cardiovascular mortality (HR = 5.8, 95% CI = 1.8, 18), and noncardiovascular mortality (HR = 4.5, 95% CI = 1.9, 11). There was no significant association between CKD severity and MALE or minor revascularization events.

CONCLUSION

The risk of mortality risk after SFA endovascular revascularization incrementally increases with decreasing renal function. However, impaired renal function is not related to the risk of adverse limb events and supports femoral revascularization in these patients.

Safety and efficacy of atrial fibrillation ablation in kidney transplant patients

INTRODUCTION

Managing atrial fibrillation in kidney transplant patients poses a challenge for both nephrologists and cardiologists. Data regarding the safety and efficacy of catheter ablation in this patient's cohort is scarce.

METHODS AND RESULTS

In this two-center prospective study, we included all consecutive kidney transplant patients who underwent atrial fibrillation ablation between April 2017 and March 2022. A 1:3 propensity score matching created a control group of non-transplant AF patients undergoing ablation. We included 16 kidney transplant patients and 48 matched controls. Ablation was successful in all patients. The periprocedural complication rate (6.3% in the kidney transplant group vs. 6.3% in the control group, p value = 1) did not differ between the two groups. One transplant patient experienced graft dysfunction after a complication. At 18 months, AF recurrence-fee rates were 69% in the transplant group and 70.1% in controls (p = 0.95). By the last follow-up, all transplant patients had discontinued antiarrhythmic drugs, while 19.6% of the patients in the control group were treated with antiarrhythmic drugs (p = 0.09). Kidney function in the transplant group remained stable (eGFR 32 [23.8, 40.5] ml/min/1.73 m2 before vs. 34 [29.8, 38] ml/min/1.73 m2 at last follow up, p = 0.93).

CONCLUSIONS

This study demonstrates that catheter ablation is a viable option for treating AF in kidney transplant patients, with comparable outcomes to non-transplanted individuals. Discontinuing antiarrhythmic drugs reduces drug interaction risks, but minimizing procedural complications remains critical to preserving graft function.

I Brazilian guideline on hypertension in dialysis of the Brazilian Society of Nephrology

Hypertension in dialysis patients (HTND) has a high prevalence, affecting at least 80% or more of patients, and its management in the nephrology practice is heterogeneous and often empirical. Knowing how to define, understand the pathophysiology, diagnose, monitor and treat with lifestyle changes, and adjust antihypertensive drugs to achieve the recommended blood pressure (BP) target - to reduce morbidity and mortality - requires specific knowl-edge and approaches within the contexts of hemodialysis (HD) and peritoneal dialysis (PD). This document is the first guideline of the Brazilian Society of Nephrology, developed by the departments of Hypertension and Dialysis. It aims to guide physicians who provide care in dialysis centers on how to manage patients with HTND, in a comprehensive and individualized manner, based on the critical appraisal of the best available scientific evidence. When such evidence is scarce or unavailable, the opinion of specialists should be recommended. The different topics covered include HTND definition (pre-HD BP ≥ 140/90 mmHg and post-HD BP ≥ 130/80 mmHg), epidemiology, and pathophysiology; diagnosis of HTND preferably with BP measurements outside the dialysis setting (BP ≥ 130/80 mmHg); complementary assessment; blood pressure targets; non-pharmacological treatment; use of the most appropriate antihypertensive medications; special situations; and complications of HTND, predominantly cardiovascular ones.

Effects of dialysis on peripheral arterial disease

End-stage renal disease is an independent risk factor for the development of peripheral arterial disease, with considerably worse outcomes in patients with concomitant diseases. It is important to realize the widespread, yet frequently asymptomatic, nature of peripheral arterial disease in patients with end-stage renal disease due to the presence of other comorbidities that decrease activity levels and sensation to allow for early recognition and timely medical management to try and mitigate otherwise poor outcomes. Despite their high risk, properly selected patients derive benefit from revascularization; both open and endovascular approaches provide similar outcomes in terms of overall survival, amputation-free survival, and limb salvage, with perhaps a slight preference toward open repair. This narrative review of the literature evaluates the epidemiology, pathophysiology, outcomes, and management strategies that provide the best possible outcomes for patients with peripheral arterial disease and end-stage renal disease.

Outcomes of Patients with Critical Limb Ischemia and Chronic Kidney Disease: A National Perspective

INTRODUCTION

Studies exploring the relationship between peripheral arterial disease (PAD), critical limb ischemia (CLI), and chronic kidney disease (CKD) and its effect on in-hospital outcomes are limited. We aimed to analyze the outcomes of patients with CKD and PAD who are admitted for CLI.

METHODS

We utilized the National Inpatient Sample (NIS) to capture hospitalizations for CLI from 2012 to 2020 and then identified cases with concomitant CKD. The primary outcome was mortality, and secondary outcomes were cerebrovascular accident, major bleeding, vasopressor requirement, percutaneous coronary intervention, cardiac arrest, acute respiratory failure, transfusion, length of stay, and total hospital charges. Multivariable logistic regression was performed to adjust for covariates.

RESULTS

A total of 441,245 patients with CLI were identified, of which 122,370 (27.7%) reported concomitant CKD. Patients with CKD had higher in-patient mortality (odds ratio [OR] 1.68, 95% confidence interval [CI], 1.17-1.68, p < 0.001), vascular complications (OR 1.31, 95% CI, 1.17-1.48, p < 0.001), acute kidney injury requiring hemodialysis (OR 3.17, 95% CI, 2.64-3.80, p < 0.001), and major bleeding (OR 1.12, 95% CI, 1.05-1.19, p < 0.001). Patients with CKD underwent minimally invasive endovascular therapy (31.08% vs. 36.73%, p < 0.0001) and invasive procedures (14.73% vs. 23.55%, p < 0.0001) less often. PAD-CLI with CKD was associated with major (20.54% vs. 16.17%, OR 1.04; p < 0.0001) and minor (26.87% vs. 19.53%, OR 1.2, p < 0.0001) amputations more often.

CONCLUSION

Patients admitted for PAD-CLI with concomitant CKD have significantly higher in-hospital mortality as compared to patients without CKD. Moreover, patients with CKD and PAD-CLI are less likely to receive revascularization and more likely to undergo amputation.

Diet and exercise in relation to lower extremity artery disease

Adherence to the Mediterranean diet (MeD) has been associated with a reduced incidence of peripheral arterial disease (PAD)/lower extremity arterial disease (LEAD) in observational trials and in a randomized trial. In secondary prevention, a lower hazard ratio for composite major adverse cardiovascular events has been associated with better adherence to MeD in a relatively small, randomized trial. This has not been confirmed in a sub-analysis of a large interventional trial of dual antithrombotic treatment. The effects of vegetarian, vegan or low carbohydrate/ketogenic diets on the incidence and outcomes of PAD/LEAD are not known. While abdominal obesity is associated with diabetes mellitus and PAD/LEAD, the lowest incidence of PAD/LEAD has been found in subjects with a body mass index 25-29.9 kg/m2. Malnutrition is a negative prognostic factor for survival of patients with chronic limb threatening ischemia. Physical activity (PA) is an acute stressor, but habitual recreational PA results in beneficial adaptations and improved health. In observational studies, lower levels of exercise and lower physical fitness have been associated with more prevalent PAD/LEAD. In contrast to coronary artery disease, that shows a reverse J-shaped relationship between long-term endurance exercise and coronary atherosclerosis, such a relationship is not known for PAD/LEAD. A general recommendation for maintaining cardiovascular health is performing regular moderate-intensity exercise with some vigorous-intensity aerobic PA, and resistance exercise at least twice a week. Combinations of healthy behaviors are more effective in preventing PAD/LEAD than a single behavioral component. In treatment of PAD/LEAD causing intermittent claudication, supervised walking training is recommended among measures of first-line treatment, while unsupervised walking training should be considered as an alternative.

Risk factors for peripheral artery disease and diabetic peripheral neuropathy among patients with type 2 diabetes

AIMS

To investigate the prevalence of peripheral artery disease (PAD) and diabetic peripheral neuropathy (DPN) and the associated risk factors among Chinese patients with type 2 diabetes mellitus.

METHODS

A cross-sectional study was conducted using data between November 1, 2018, and December 31, 2022. PAD was defined as ABI ≤ 0.9. DPN diagnosis involved specialized physician assessments using questionnaires and vibration perception threshold tests. Logistic regression analysis was used to identify related factors. We also evaluated the association between the clustering of risk factors and disease incidence.

RESULTS

The study population comprised 13,315 patients (mean age: 63.3 years). 4.9 % of the patients had PAD and 43.9 % had DPN. Multivariate regression analysis revealed advanced age, smoking, hypertension, coronary heart disease, dyslipidemia, elevated HbA1c, and uric acid levels as independent risk factors for PAD. For DPN, independent risk factors included advanced age, female gender, hypertension, coronary heart disease, elevated total cholesterol, triglycerides, lipoprotein(a), fasting plasma glucose, HbA1c, alkaline phosphatase, cystatin C, albumin-to-creatinine ratio, and elevated homocysteine levels, whereas apolipoprotein A was a protective factor. The clustering of risk factors was prevalent and associated with higher disease risk.

CONCLUSIONS

Our study contributed to identifying high-risk individuals and improving lower limb health among diabetic individuals.

Virtual Monoenergetic Imaging of Lower Extremities Using Dual-Energy CT Angiography in Patients with Diabetes Mellitus

BACKGROUND

Type 2 diabetes mellitus (DM) is the most common metabolic disorder in the world and an important risk factor for peripheral arterial disease (PAD). CT angiography represents the method of choice for the diagnosis, pre-operative planning, and follow-up of vascular disease. Low-energy dual-energy CT (DECT) virtual mono-energetic imaging (VMI) has been shown to improve image contrast, iodine signal, and may also lead to a reduction in contrast medium dose. In recent years, VMI has been improved with the use of a new algorithm called VMI+, able to obtain the best image contrast with the least possible image noise in low-keV reconstructions.

PURPOSE

To evaluate the impact of VMI+ DECT reconstructions on quantitative and qualitative image quality in the evaluation of the lower extremity runoff.

MATERIALS AND METHODS

We evaluated DECT angiography of lower extremities in patients suffering from diabetes who had undergone clinically indicated DECT examinations between January 2018 and January 2023. Images were reconstructed with standard linear blending (F_0.5) and low VMI+ series were generated from 40 to 100 keV, in an interval of 15 keV. Vascular attenuation, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated for objective analysis. Subjective analysis was performed using five-point scales to evaluate image quality, image noise, and diagnostic assessability of vessel contrast.

RESULTS

Our final study cohort consisted of 77 patients (41 males). Attenuation values, CNR, and SNR were higher in 40-keV VMI+ reconstructions compared to the remaining VMI+ and standard F_0.5 series (HU: 1180.41 ± 45.09; SNR: 29.91 ± 0.99; CNR: 28.60 ± 1.03 vs. HU 251.32 ± 7.13; SNR: 13.22 ± 0.44; CNR: 10.57 ± 0.39 in standard F_0.5 series) (p < 0.0001). Subjective image rating was significantly higher in 55-keV VMI+ images compared to the other VMI+ and standard F_0.5 series in terms of image quality (mean score: 4.77), image noise (mean score: 4.39), and assessability of vessel contrast (mean value: 4.57) (p < 0.001).

CONCLUSIONS

DECT 40-keV and 55-keV VMI+ showed the highest objective and subjective parameters of image quality, respectively. These specific energy levels for VMI+ reconstructions could be recommended in clinical practice, providing high-quality images with greater diagnostic suitability for the evaluation of lower extremity runoff, and potentially needing a lower amount of contrast medium, which is particularly advantageous for diabetic patients.

Prevalence and Predictors of Peripheral Vascular Disease Amongst Predialysis Hypertensive Chronic Kidney Disease Patients in Southern Nigeria

BACKGROUND

Peripheral vascular disease (PVD) is an atherosclerotic disease associated with increased morbidity and mortality among chronic kidney disease (CKD) patients. However, despite the substantial burden of PVD in CKD, local data are lacking.

OBJECTIVE

To determine the prevalence and predictors of PVD in predialysis CKD patients.

METHOD AND MATERIALS

The study was cross-sectional. One hundred fifty hypertensive CKD patients and age- and sex-matched hypertensive non-CKD subjects were consecutively enrolled at the renal unit of Delta State University Teaching Hospital (DELSUTH), Oghara. Structured questionnaires were used to obtain information on participants' demographic data and health status. PVD was defined by an ankle-brachial index of < 0.9 or > 1.4 in either lower extremity. eGFR was calculated from serum creatinine using the MDRD equation.

RESULTS

The mean ages of the study and control groups were 48±14 and 51±15years, respectively. The sex ratio was 3:2 in favour of males for both the study and control groups. The majority of the study group was in CKD stage 4 (44%). The prevalence of PVD was higher among the CKD group compared with controls (24.0% vs. 14.7%). Of the CKD patients with PVD, 11.1% were symptomatic. Predictors of PVD in the study group were eGFR (B=0.010, 95%CI: 0.007-0.013), diastolic BP (B=-0.005, 95%CI: -0.007- -0.002), MAP (B=-0.018, 95%CI: -0.027- -0.008), urinary ACR (B=-0.0036, 95%CI: -0.040- -0.024) and smoking history (p<0.001, OR=14.71).

CONCLUSION AND RECOMMENDATION

PVD is common and largely asymptomatic in CKD patients. The predictors of PVD in this study were eGFR, diastolic BP, mean arterial pressure (MAP), urinary albumin to creatinine ratio (ACR), and smoking. A proactive assessment of PVD and early intervention in CKD patients is needed.

The significance of follow-up serum uric acid levels in predicting all-cause mortality and cardiovascular mortality in peritoneal dialysis patients

BACKGROUND

This study aimed to analyze the change of serum uric acid (SUA) level post peritoneal dialysis (PD), and the correlation between follow-up SUA and prognosis in patients with PD.

METHODS

A total of 1402 patients with PD were evaluated. We graded SUA levels into four grades at baseline, 6 months, 12 months, 18 months, and 24 months post PD, and then compared all-cause mortality and cardiovascular mortality among patients with different SUA grades at each time point. Kaplan-Meier and Cox proportional-hazards regression models were used in the analysis.

RESULTS

The SUA levels were 7.97 ± 1.79, 7.12 ± 1.48, 7.05 ± 1.33, 7.01 ± 1.30, and 6.93 ± 1.26 mg/dl at baseline, 6, 12, 18, and 24 months, respectively. There was significant difference on all-cause mortality among patients with PD with different graded SUA levels at 6 months post PD (p = 0.010), and the all-cause mortality was lowest in patients with the grade of 5.65 mg/dl ≤ SUA <7.13 mg/dl.

CONCLUSION

SUA level decreased after PD during follow-up. At 6 months post PD, the grade of 5.65 mg/dl ≤ SUA <7.13 mg/dl was appropriate for better patients' survival.

Race, Social Determinants of Health, and Length of Stay Among Hospitalized Patients With Heart Failure: An Analysis From the Get With The Guidelines-Heart Failure Registry

BACKGROUND

Racial disparities in heart failure hospitalization and mortality are well established; however, the association between different social determinants of health (SDOH) and length of stay (LOS) and the extent to which this association may differ across racial groups is not well established.

METHODS

We utilized data from the Get With The Guidelines-Heart Failure registry to evaluate the association between SDOH, as determined by patients' residential ZIP Code and LOS among patients hospitalized with heart failure. We also assessed the race-specific contribution of the ZIP Code-level SDOH to LOS in patients of Black and non-Black races. Finally, we evaluated SDOH predictors of racial differences in LOS at the hospital level.

RESULTS

Among 301 500 patients (20.2% Black race), the median LOS was 4 days. In adjusted analysis accounting for patient-level and hospital-level factors, SDOH parameters of education, income, housing instability, and foreign-born were significantly associated with LOS after adjusting for clinical status and hospital-level factors. SDOH parameters accounted for 25.8% of the total attributable risk for prolonged LOS among Black patients compared with 10.1% in patients of non-Black race. Finally, hospitals with disproportionately longer LOS for Black versus non-Black patients were more likely to care for disadvantaged patients living in ZIP Codes with a higher percentage of foreign-born and non-English speaking areas.

CONCLUSIONS

ZIP Code-level SDOH markers can identify patients at risk for prolonged LOS, and the effects of SDOH parameters are significantly greater among Black adults with heart failure as compared with non-Black adults.

Rotablation in Patients with Advanced Renal Insufficiency through End-Stage Renal Disease: Short- and Intermediate-Term Results

Objective. Patients with advanced renal insufficiency are at high risk of coronary artery disease (CAD) and complex lesions. Treating complex calcified lesion with rotational atherectomy (RA) in these patients might be associated with higher risks and poorer outcomes. This study was set to evaluate features and outcomes of RA in these patients. Method. Consecutive patients who received coronary RA from April 2010 to April 2018 were queried from the Cath Lab database. The procedural details, angiography, and clinical information were reviewed in detail. Results. A total of 411 patients were enrolled and divided into Group A (baseline serum creatinine <5 mg/dl, n = 338) and Group B (baseline serum creatinine ≥ 5 mg/dl through ESRD, n = 73). Most patients had high-risk features (65.7% of acute coronary syndrome (ACS), 14.1% of ischemic cardiomyopathy, and 5.1% of cardiogenic shock). Group B patients were significantly younger (66.8 ± 11.4 vs. 75.2 ± 10.7 years, $p<0.001$ ) and had more RCA and LCX but less LAD treated with RA. No difference was found in lesion location, vessel tortuosity, bifurcation lesions, chronic total occlusion, total lesion length, or total lesion numbers between the two groups. Less patients in Group B obtained completion of RA (95.9% vs 99.1%, $p=0.037$ ). There was no difference in the incidence of procedural complication or acute contrast-induced nephropathy. Group B patients had more deaths and MACE while in the hospital. The MACE and CV MACE were also higher in Group B patients at 180 days and one year, mostly due to TLR and TVR. Multivariate regression analysis showed that ACS, age, peripheral artery disease (PAD), advanced renal insufficiency, ischemic cardiomyopathy/shock, and high residual SYNTAX score were independent risk factors for in-hospital MACE, whereas ACS, advanced renal insufficiency, ischemic cardiomyopathy/shock, triple-vessel disease, and PAD independently predicted MACE at 6 months. Conclusions. Rotablation is feasible, safe, and could be carried out with very high success rate in very-high-risk patients with advanced renal dysfunction through ESRD without an increase in procedural complication.

Determinants and Outcomes Associated With Urinary Calcium Excretion in Chronic Kidney Disease

CONTEXT

Abnormalities in calcium metabolism are common in chronic kidney disease (CKD). Diminished urinary calcium excretion may promote vascular calcification and increased urinary calcium excretion may lead to nephrolithiasis and nephrocalcinosis, conditions associated with CKD.

OBJECTIVE

To study predictors of urinary calcium excretion and its association with adverse clinical outcomes in CKD.

DESIGN, SETTING AND PATIENTS

This study assessed 3768 nondialysis participants in the Chronic Renal Insufficiency Cohort study from April 2003 to September 2008. Participants were followed up to October 2018.

EXPOSURE

Clinically plausible predictors of urinary calcium excretion and 24-h urinary calcium excretion at baseline.

MAIN OUTCOME MEASURES

Urinary calcium excretion; incident end stage kidney disease (ESKD), CKD progression [50% estimated glomerular filtration rate (eGFR) decline or incident ESKD], all-cause mortality, and atherosclerotic cardiovascular disease events.

RESULTS

eGFR was positive correlated with 24-h urinary calcium excretion. The variables most strongly associated with 24-h urinary calcium excretion in males and females were 24-h urinary sodium (β = 0.19 and 0.28, respectively), serum parathyroid hormone (β = -0.22 and -0.20, respectively), loop diuretics (β = 0.36 and 0.26, respectively), thiazide diuretics (β = -0.49 and -0.53, respectively), and self-identified black race (β = -0.23 and -0.27, respectively). Lower urinary calcium excretion was associated with greater risks of adverse outcomes, but these associations were greatly attenuated or nullified after adjustment for baseline eGFR.

CONCLUSION

Urinary calcium excretion is markedly lower in individuals with CKD compared to the general population. Determinants of urinary calcium excretion differed between sexes and levels of CKD. Associations between urinary calcium excretion and adverse clinical events were substantially confounded by eGFR.

Midlife Cardiorespiratory Fitness and the Development of Peripheral Artery Disease in Later Life

Background Data are sparse on the prospective associations between physical activity and incidence of lower extremity peripheral artery disease (PAD). Methods and Results Linking participant data from the CCLS (Cooper Center Longitudinal Study) to Medicare claims files, we studied 19 023 participants with objectively measured midlife cardiorespiratory fitness through maximal effort on the Balke protocol who survived to receive Medicare coverage between 1999 and 2009. The study aimed to determine the association between midlife cardiorespiratory fitness and incident PAD with proportional hazards intensity models, adjusted for age, sex, body mass index, and other covariates, to PAD failure time data. During 121 288 person-years of Medicare follow-up, we observed 805 PAD-related hospitalizations/procedures among 19 023 participants (21% women, median age 50 years). Lower midlife fitness was associated with a higher rate of incident PAD in patients aged 65 years and older (low fit [quintile 1]: 11.4, moderate fit [quintile 2 to 3]: 7.8, and high fit [quintile 4 to 5]: 5.7 per 1000 person years). After multivariable adjustment for common predictors of incident PAD such as age, body mass index, hypertension, and diabetes, these findings persisted. Lower risk for PAD per greater metabolic equivalent task of fitness was observed (hazard ratio [HR], 0.93 [95% CI, 0.90-0.97]; P<0.001). Among a subset of patients with an additional fitness assessment, each 1 metabolic equivalent task increase from baseline fitness was associated with decreased risk of incident PAD (HR, 0.90 [95% CI, 0.82-0.99]; P=0.03). Conclusions Cardiorespiratory fitness in healthy, middle-aged adults is associated with lower risk of incident PAD in later life, independent of other predictors of incident PAD.

Accuracy of Ankle-Brachial Index, Toe-Brachial Index, and Risk Classification Score in Discriminating Peripheral Artery Disease in Patients With Chronic Kidney Disease

The accuracy of ankle-brachial index (ABI) and toe-brachial index (TBI) in discriminating lower extremity peripheral artery disease (PAD) has not been evaluated in patients with chronic kidney disease (CKD). We measured ABI, TBI, and Doppler ultrasound in 100 predialysis patients with CKD without revascularization or amputation. Leg-specific ABI was calculated using higher systolic blood pressure (SBP) in posterior tibial or dorsalis pedis artery divided by higher brachial SBP; alternative ABI was calculated using lower SBP in posterior tibial or dorsalis pedis artery. PAD was defined as ≥50% stenosis detected by Doppler ultrasound. PAD risk classification score was calculated using cardiovascular disease risk factors. The area under the curve (AUC, 95% confidence interval [CI]) for discriminating ultrasound-diagnosed PAD was 0.78 (0.69 to 0.87) by ABI, 0.80 (0.71 to 0.89) by alternative ABI, and 0.74 (0.63 to 0.86) by TBI. Sensitivity and specificity were 25% and 97% for ABI ≤0.9, 41% and 95% for alternative ABI ≤0.9, and 45% and 93% for TBI ≤0.7, respectively. AUC (95% CI) of PAD risk classification score was 0.86 (0.78 to 0.94) with sensitivity and specificity of 95% and 60% for risk score ≥0.10, 76% and 76% for risk score ≥0.25, and 43% and 95% for risk score ≥0.55. Combining risk score with ABI, alternative ABI, and TBI increased AUC (95% CI) to 0.89 (0.82 to 0.96), 0.89 (0.80 to 0.98), and 0.87 (0.78 to 0.96), respectively. In conclusion, current ABI and TBI diagnostic criteria have high specificity but low sensitivity for classifying PAD in patients with CKD. PAD classification risk score based on cardiovascular disease risk factors improves the accuracy of PAD classification.

Tryptophan metabolites suppress Wnt pathway and promote adverse limb events in CKD patients

Chronic kidney disease (CKD) imposes a strong and independent risk for peripheral artery disease (PAD). While solutes retained in CKD patients (uremic solutes) inflict vascular damage, their role in PAD remains elusive. Here, we show that the dietary tryptophan-derived uremic solutes including indoxyl sulfate (IS) and kynurenine (Kyn) at concentrations corresponding to those in CKD patients suppress β-catenin in several cell types, including microvascular endothelial cells (ECs), inhibiting Wnt activity and proangiogenic Wnt targets in ECs. Mechanistic probing revealed that these uremic solutes downregulated β-catenin in a manner dependent on serine 33 in its degron motif and through the aryl hydrocarbon receptor (AHR). Hindlimb ischemia in adenine-induced CKD and IS solute–specific mouse models showed diminished β-catenin and VEGF-A in the capillaries and reduced capillary density, which correlated inversely with blood levels of IS and Kyn and AHR activity in ECs. An AHR inhibitor treatment normalized postischemic angiogenic response in CKD mice to a non-CKD level. In a prospective cohort of PAD patients, plasma levels of tryptophan metabolites and plasma’s AHR-inducing activity in ECs significantly increased the risk of future adverse limb events. This work uncovers the tryptophan metabolite/AHR/β-catenin axis as a mediator of microvascular rarefaction in CKD patients and demonstrates its targetability for PAD in CKD models.

Clinical outcomes among patients with chronic kidney disease hospitalized with diabetic foot disorders: A nationwide retrospective study

INTRODUCTION

Diabetic foot ulcerations or infections (DFUs/DFIs) are common complications of patients with diabetes. This study aimed to explore the impact of non-dialysis and dialysis CKD on hospitalized patients with DFUs/DFIs.

METHODS

A retrospective cohort study was conducted using the National Inpatient Sample database for the years 2017 and 2018. Patients hospitalized for DFUs/DFIs were included in the study. The primary outcome was lower limb amputations. The secondary outcomes were inpatient mortality, sepsis, length of stay (LOS), total hospitalization charges (THC) and disposition.

RESULTS

A total of 121,815 hospitalizations were included (26.1% non-dialysis CKD; 8.4% dialysis CKD). There was no significant difference in amputation rates between those on non-dialysis CKD (adjusted odds ratio [aOR]: 0.96; 95% confidence interval [CI]: 0.87-1.06) and dialysis CKD (aOR: 1.04, [95% CI: 0.91-1.12]) when compared to non-CKD group. Dialysis CKD group had increased odds of undergoing major amputation (aOR: 1.74, [95% CI: 1.32-2.29]), in-hospital mortality (aOR: 3.77 [95% CI: 1.94-7.31]), sepsis (aOR: 1.83 [95% CI: 1.27-2.62]), longer LOS (adjusted mean difference [aMD]: 1.46 [95 CI: 1.12-1.80) and higher THC (adjusted mean difference [aMD]: $20,148 [95% CI: $15,968-$24,327]). Non-dialysis CKD group had increased odds of sepsis (aOR: 1.36 [95% CI: 1.02-1.82]), less likely to be discharged home (aOR: 0.87 [95% CI: 0.80-0.95]), longer LOS (aMD: 0.91 [95% CI 0.69-1.13]) and higher THC (aMD: $20,148 [95% CI: $15,968-$24,327]).

CONCLUSION

Patients with CKD on dialysis had higher odds of undergoing major amputation. CKD increased the odds of in-hospital morbidity and resource utilization, with the most significant is for those on dialysis.

Role, Laboratory Assessment and Clinical Relevance of Fibrin, Factor XIII and Endogenous Fibrinolysis in Arterial and Venous Thrombosis

Diseases such as myocardial infarction, ischaemic stroke, peripheral vascular disease and venous thromboembolism are major contributors to morbidity and mortality. Procoagulant, anticoagulant and fibrinolytic pathways are finely regulated in healthy individuals and dysregulated procoagulant, anticoagulant and fibrinolytic pathways lead to arterial and venous thrombosis. In this review article, we discuss the (patho)physiological role and laboratory assessment of fibrin, factor XIII and endogenous fibrinolysis, which are key players in the terminal phase of the coagulation cascade and fibrinolysis. Finally, we present the most up-to-date evidence for their involvement in various disease states and assessment of cardiovascular risk.

Progression of retinopathy and incidence of cardiovascular disease: findings from the Chronic Renal Insufficiency Cohort Study

PURPOSE

Chronic kidney disease (CKD) patients often develop cardiovascular disease (CVD) and retinopathy. The purpose of this study was to assess the association between progression of retinopathy and concurrent incidence of CVD events in participants with CKD.

DESIGN

We assessed 1051 out of 1936 participants in the Chronic Renal Insufficiency Cohort Study that were invited to have fundus photographs obtained at two timepoints separated by 3.5 years, on average.

METHODS

Using standard protocols, presence and severity of retinopathy (diabetic, hypertensive or other) and vessel diameter calibre were assessed at a retinal image reading centre by trained graders masked to study participants' information. Participants with a self-reported history of CVD were excluded. Incident CVD events were physician adjudicated using medical records and standardised criteria. Kidney function and proteinuria measurements along with CVD risk factors were obtained at study visits.

RESULTS

Worsening of retinopathy by two or more steps in the EDTRS retinopathy grading scale was observed in 9.8% of participants, and was associated with increased risk of incidence of any CVD in analysis adjusting for other CVD and CKD risk factors (OR 2.56, 95% CI 1.25 to 5.22, p<0.01). After imputation of missing data, these values were OR=1.66 (0.87 to 3.16), p=0.12.

CONCLUSION

Progression of retinopathy is associated with higher incidence of CVD events, and retinal-vascular pathology may be indicative of macrovascular disease even after adjustment for kidney diseases and CVD risk factors. Assessment of retinal morphology may provide important information when assessing CVD in patients with CKD.

Indoxyl Sulfate and Incident Peripheral Artery Disease in Hemodialysis Patients

Peripheral artery disease (PAD) is highly prevalent among patients with chronic kidney disease (CKD) and portends a very poor prognosis. Indoxyl sulfate has been shown to induce atherothrombosis and impaired neovascularization in uremic mice. However, there is no clinical evidence regarding the role of indoxyl sulfate in PAD associated with CKD. We examined associations between indoxyl sulfate and incident symptomatic lower extremity PAD events as well as major adverse cardiovascular events (MACE) and all-cause mortality using Cox proportional hazards models in a prospective cohort of 200 hemodialysis patients free of PAD at baseline. Patients were considered as having PAD if they developed PAD symptoms confirmed by an ankle-brachial index with waveforms, duplex ultrasound or angiography, and/or major adverse limb events including revascularization and amputation. During a median follow-up of 6.5 years, 37 patients (18.5%) experienced incident symptomatic PAD. MACE occurred in 52 patients, and a total of 85 patients died. After adjusting for traditional risk factors for PAD, including age, current smoking, diabetes, and cardiovascular disease, indoxyl sulfate was significantly associated with the risk of PAD (hazard ratio (HR), 1.19 for every 10-μg/mL increase in indoxyl sulfate; 95% confidence interval (CI), 1.05–1.35). However, indoxyl sulfate was not associated with risk of MACE (HR, 1.00; 95% CI, 0.90–1.12) or death from any cause (HR, 0.98; 95% CI, 0.90–1.07). Indoxyl sulfate was associated with incident symptomatic PAD but not with MACE or all-cause mortality, suggesting that indoxyl sulfate toxicity may be unique to PAD among hemodialysis patients.

Peripheral Artery Disease in Vulnerable Patient Populations: Outcomes of Orbital Atherectomy in Native Americans Compared to Non-Native Americans. A Single-Center Experience in Rural Oklahoma

BACKGROUND/PURPOSE

Although the incidence of peripheral artery disease (PAD) and amputations is higher in Native Americans (NA) than Caucasians, the study of revascularization NA is limited, resulting in their under representation in clinical studies. Orbital atherectomy (OA) is widely utilized for endovascular revascularization of significantly calcified peripheral arteries and has been shown to improve limb salvage rates.

METHODS/MATERIALS

A cohort of 74 consecutive PAD subjects undergoing OA treatment was retrospectively analyzed via Kaplan Meier (KM) and Propensity Score Matched (PSM) analysis.

RESULTS

A significant proportion of the subjects were NA (16.2%). Compared to the non-NA, the NA had higher numerical baseline rates of wounds, dialysis, chronic kidney disease (CKD), and critical limb ischemia, but were numerically less likely to smoke and had similar rates of diabetes. There were very high rates of severe calcification (100% vs. 87%) and pre-procedure diameter stenosis (99% vs. 95%) in both groups. The NA and non-NA had good angiographic outcomes, resulting in low rates of post-procedure residual diameter stenosis (10% vs. 11%). Lastly, KM analysis indicated high freedom from amputation in both groups at 1 year (89% vs. 95%), as well as in the PSM subjects (89% vs. 100%).

CONCLUSIONS

Despite numerically higher rates of co-morbidities at baseline (e.g., CKD, dialysis, and presence of non-healing wounds), the NA underwent successful revascularization with OA, resulting in high freedom from amputation at 1-year. Given the small sample size of NA, these results may not be generalizable-thus, larger studies on NA are warranted.

How ESKD complicates the management of diabetic foot ulcers: The vital role of the dialysis team in prevention, early detection, and support of multidisciplinary treatment to reduce lower extremity amputations

Diabetic foot ulcers do not heal as well in ESKD as in the absence of kidney failure, and rates of recurrent foot ulcers, as well as lower extremity amputation, are higher. This review of the literature highlights the vital role of the dialysis team in prevention, early detection, and support of treatment of diabetic foot ulcers. Our review has five goals-(a) increase nephrologists' understanding of the high morbidity and mortality associated with chronic foot ulcers and (lower extrimity) LE amputations in ESKD; (b) promote nephrologists' understanding of grading systems for diabetic foot ulcer severity, in order to expedite communication with local diabetic foot experts; (c) promote collaboration between nephrologists and infectious disease specialists regarding the dose, route, and delivery logistics of intravenous antibiotics for infected chronic foot ulcers, in particular in the presence of osteomyelitis and other deep-seated infections; (d) increase the awareness of dialysis nurses, technicians, dietitians, social workers and administrators regarding evidence-based and multidisciplinary approaches to patients' diabetic foot ulcers; (e) encourage the application of published works integrating patient-centered diabetic foot education into the dialysis setting to reduce lower extremity amputations.

Peripheral arterial disease diagnosed by ankle-brachial index: Predictor for early renal replacement therapy in chronic kidney disease

Our study aimed to investigate the relationship between ankle-brachial index (ABI) and need for early renal replacement therapy (RRT) in predialysis patients with chronic kidney disease (CKD). A total of 112 patients (62% men) with pre-dialysis CKD, seen in the outpatient clinic, were included, and ABI was obtained as per standard protocol. Peripheral arterial disease (PAD) was defined as ABI <0.9 or >1.3 in either leg. The clinical data were analyzed, and the risk factors for early RRT were determined by multivariate logistic regression analysis. The prevalence of PAD was 44% in predialysis CKD patients. Over three years' follow- up, 14.2% required RRT; 11.3% developed major cardiovascular event (myocardial infarction, stroke, or death). A total of 26 events occurred. The incidence of all events was significantly higher in patients with abnormal ABI than in those with normal ABI (34.7% vs. 12.7%; log rank P = 0.02). PAD was associated with all events [hazard ratio (HR): 2.72; 95% CI: 1.04-7.17; P = 0.042] as also the need for RRT (HR 3.2; 95% Cl: 1.005-10.23; P = 0.049), on univariate cox proportional hazard analysis. Multivariate logistic regression analysis adjusted for other risk factors identified that PAD remained an independent predictor for the need for early RRT (HR: 12.2; 95%Cl: 2.2-66.5; P = 0.004) and all events (HR: 3.5; 95% Cl: 0.9-13.5; P = 0.032). PAD was an independent predictor for RRT requirement in predialysis CKD.

High serum uric acid level is a mortality risk factor in peritoneal dialysis patients: a retrospective cohort study

Background

The results remain controversial with regards to the impact of serum uric acid on clinical outcomes from peritoneal dialysis population. The aim of our study was to investigate the influence of serum uric acid levels on mortality in peritoneal dialysis patients.

Methods

Data on 9405 peritoneal dialysis patients from the Zhejiang Renal Data system were retrospectively analyzed. All demographic and laboratory data were recorded at baseline. The study cohort was divided into quintiles according to baseline uric acid level (mg/dL): Q1 (< 6.06), Q2 (6.06–6.67), Q3 (6.68–7.27) (reference), Q4 (7.28–8.03), and Q5 (≥8.04). Hazards ratio (HR) of all-cause and cardiovascular mortality was calculated.

Results

Mean serum uric acid was 7.07 ± 1.25 mg/dL. During a median follow-up of 29.4 (range, 3.0 to 115.4) months, 1226 (13.0%) patients died, of which 515 (5.5%) died of cardiovascular events. The Kaplan-Meier survival curves showed that patients in the middle uric acid quintile (Q3: 6.68–7.27) exhibited the highest patient and cardiovascular survival rates (log-rank test P < 0.05). Multivariate Cox regression analysis showed that, using Q3 as the reference, in the fully adjusted model, a higher uric acid level (Q4: 7.28–8.03, and Q5: ≥8.04) was significantly associated with higher all-cause mortality (Model 3; Q4: HR, 1.335, 95% CI, 1.073 to 1.662, P = 0.009; Q5: HR, 1.482, 95% CI, 1.187 to 1.849, P = 0.001), but not with cardiovascular mortality. The adverse effect of higher uric acid level (≥7.28 mg/dL) on all-cause mortality was more prominent in groups such as male, hypoalbuminemia, normal weight, non-diabetes mellitus at baseline rather than in their counterparts respectively.

Conclusions

A higher uric acid level was an independent risk factor for all-cause mortality in peritoneal dialysis patients.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0379-y) contains supplementary material, which is available to authorized users.

Unique aspects of peripheral artery disease in patients with chronic kidney disease

Peripheral artery disease (PAD) represents a major health care burden. Despite the advent of screening and interventional procedures, the long-term clinical outcomes remain suboptimal, especially in patients with chronic kidney disease (CKD). While CKD and PAD share common predisposing factors, emerging studies indicate that their co-existence is not merely an association; instead, CKD represents a strong, independent risk factor for PAD. These findings implicate CKD-specific mediators of PAD that remain incompletely understood. Moreover, there is a need to understand the mechanisms underlying poor outcomes after interventions for PAD in CKD. This review discusses unique clinical aspects of PAD in patients with CKD, including high prevalence and worse outcomes after vascular interventions and the influence of renal allograft transplantation. In doing so, it also highlights underappreciated aspects of PAD in patients with CKD, such as disparities in revascularization and higher peri-procedural mortality. While previous reviews have discussed general mechanisms of PAD pathogenesis, focusing on PAD in CKD, this review underscores a need to probe for CKD-specific pathogenic pathways that may unravel novel biomarkers and therapeutic targets in PAD and ultimately improve the risk stratification and management of patients with CKD and PAD.

Peroneal bypass versus endovascular peroneal intervention for critical limb ischemia

OBJECTIVE

The peroneal artery is a well-established target for bypass in patients with critical limb ischemia (CLI). The objective of this study was to evaluate the outcomes of peroneal artery revascularization in terms of wound healing and limb salvage in patients with CLI.

METHODS

Patients presenting between 2006 and 2013 with CLI (Rutherford 4-6) and isolated peroneal runoff were included in the study. They were divided into patients who underwent bypass to the peroneal artery and those who underwent endovascular peroneal artery intervention. Demographics, comorbidities, and follow-up data were recorded. Wounds were classified by Wound, Ischemia, foot Infection (WIfI) score. The primary outcome was wound healing; secondary outcomes included mortality, major amputation, and patency.

RESULTS

There were 200 limbs with peroneal bypass and 138 limbs with endovascular peroneal intervention included, with mean follow-up of 24.0 ± 26.3 and 14.5 ± 19.1 months, respectively (P = .0001). The two groups were comparable in comorbidities, with the exception of the endovascular group's having more patients with cardiac and renal disease and diabetes mellitus but fewer patients with smoking history. Based on WIfI criteria, ischemia scores were worse in bypass patients, but wound and foot infection scores were worse in endovascular patients. Perioperatively, bypass patients had higher rates of myocardial infarction (4.5% vs 0%; P = .012) and incisional complications (13.0% vs 4.4%; P = .008). At 12 months, the bypass group compared with the endovascular group had better primary patency (47.9% vs 23.4%; P = .002) and primary assisted patency (63.6% vs 42.2%; P = .003) and a trend toward better secondary patency (74.2% vs 63.5%; P = .11). There were no differences in the rate of wound healing (52.6% vs 37.7% at 1 year; P = .09) or freedom from major amputation (81.5% vs 74.7% at 1 year; P = .37). In a multivariate analysis, neuropathy was associated with improved wound healing, whereas WIfI wound score, cancer, chronic renal insufficiency, and smoking were associated with decreased wound healing. Treatment modality was not a significant predictor (P = .15).

CONCLUSIONS

Endovascular peroneal artery intervention results in poorer primary and primary assisted patency rates than surgical bypass to the peroneal artery but provides similar wound healing and limb salvage rates with a lower rate of complications. In appropriately selected patients, endovascular intervention to treat the peroneal artery is a low-risk intervention that may be sufficient to heal ischemic foot wounds.

Heel Wounds Predict Mortality but Not Amputation after Infrapopliteal Revascularization

BACKGROUND

Ischemic heel ulcerations are generally thought to carry a poor prognosis for limb salvage. We hypothesized that patients undergoing infrapopliteal revascularization for heel wounds, either bypass or endovascular intervention, would have lower wound healing rates and amputation-free survival (AFS) than patients with forefoot wounds.

METHODS

A retrospective chart review was performed on patients who presented between 2006 and 2013 to our institution with ischemic foot wounds and infrapopliteal arterial disease and underwent either pedal bypass or endovascular tibial artery intervention. Data were collected on patient demographics, comorbidities, wound characteristics, procedural details, and postoperative outcomes then analyzed by initial wound classification. The primary outcome was major amputation or death.

RESULTS

Three hundred ninety-eight limbs underwent treatment for foot wounds; accurate wound data were available in 380 cases. There were 101 bypasses and 279 endovascular interventions, with mean follow-up of 24.6 and 19.9 months, respectively (P = 0.02). Heel wounds comprised 12.1% of the total with the remainder being forefoot wounds; there was no difference in treatment modality by wound type (P = 0.94). Of 46 heel wounds, 5 (10.9%) had clinical or radiographic evidence of calcaneal osteomyelitis. Patients with heel wounds were more likely to have diabetes mellitus (DM) (P = 0.03) and renal insufficiency (P = 0.004). 43.1% of wounds healed within 1 year, with no difference by wound location (P = 0.30). Major amputation rate at 1 year was 17.8%, with no difference by wound location (P = 0.81) or treatment type (P = 0.33). One- and 3-year AFS was 66.2% and 44.0% for forefoot wounds and 45.7% and 17.6% for heel wounds, respectively (P = 0.001). In a multivariate analysis, heel wounds and endovascular intervention were both predictors of death; however, there was significant interaction such that endovascular intervention was associated with higher mortality in patients with forefoot wounds (hazard ratio 2.25, P < 0.001) but not those with heel wounds (hazard ratio 0.67, P = 0.31).

CONCLUSIONS

Patients presenting with heel ulceration who undergo infrapopliteal revascularization are prone to higher mortality despite equivalent rates of amputation and wound healing and regardless of treatment modality. These patients may benefit from an endovascular-first strategy.

Bypass versus endovascular intervention for healing ischemic foot wounds secondary to tibial arterial disease

OBJECTIVE

Pedal (inframalleolar) bypass is a long-standing therapy for tibial arterial disease in patients with ischemic tissue loss. Endovascular tibial intervention is an appealing alternative with lower risks of perioperative mortality or complications. Our objective was to compare the effectiveness of these two treatment modalities with respect to patency and limb-related clinical outcomes.

METHODS

We performed a retrospective chart review of patients presenting between 2006 and 2013 with ischemic foot wounds and infrapopliteal arterial disease who underwent a revascularization procedure (either open surgical bypass to an inframalleolar target or endovascular tibial intervention). Data were collected on baseline demographics and comorbidities, procedural details, and postprocedure outcomes. The primary outcome was successful healing of the index wound, with mortality, major amputation, and patency assessed as secondary outcomes.

RESULTS

We identified 417 patients who met our eligibility criteria; 105 underwent surgical bypass and 312 underwent endovascular intervention, with mean follow-up of 25.0 and 20.2 months, respectively (P = .08). The endovascular patients were older at baseline (P = .009), with higher rates of hyperlipidemia (P = .02), prior cerebrovascular accidents (P = .04), and smoking history (P = .04). Within 30 days postoperatively, there was no difference in mortality (P = .31), but bypass patients had longer hospital length of stay (P < .0001), higher rate of discharge to nursing facility (P < .001), and higher rates of myocardial infarctions (P = .03) and wound complications (P < .001). At 6 months, the rate of wound healing was 22.4% in the bypass group compared with 29.0% in the endovascular group (P = .02). At 1 year, survival was higher after bypass (86.2% vs 70.4%; P < .0001), but freedom from major amputation was similar (84.9% vs 82.8%; P = .42). Primary patency (53.1% vs 38.2%; P = .002) and primary assisted patency (76.6% vs 51.7%; P < .0001) were higher in the bypass group, but there was no difference in secondary patency (77.3% vs 73.8%; P = .13).

CONCLUSIONS

Endovascular tibial intervention is associated with poorer primary patency but similar secondary patency and wound healing rates compared with the "gold standard" of surgical bypass to a pedal target. In patients with tibial arterial disease, endovascular intervention should be considered a lower risk alternative to pedal bypass that provides similar clinical outcomes.

Prevalence of peripheral artery disease (PAD) and factors associated: An epidemiological analysis from the population-based Screening PRE-diabetes and type 2 DIAbetes (SPREDIA-2) study

AIM

To describe the prevalence of Peripheral Artery Disease (PAD) in a random population sample and to evaluate its relationship with Mediterranean diet and with other potential cardiovascular risk factors such as serum uric acid and pulse pressure in individuals ranged 45 to 74 years.

METHODS

Cross-sectional analysis of 1568 subjects (mean age 6.5 years, 43% males), randomly selected from the population. A fasting blood sample was obtained to determine glucose, lipids, and HbA1C levels. An oral glucose tolerance test was performed in non-diabetic subjects. PAD was evaluated by ankle-brachial index and/or having a prior diagnosis.

RESULTS

PAD prevalence was 3.81% (95% CI, 2.97-4.87) for all participants. In men, PAD prevalence was significantly higher than in women [5.17% (95% CI, 3.74-7.11) vs. 2.78% (95% CI, 1.89-4.07); p = 0.014]. Serum uric acid in the upper quartile was associated with the highest odds ratio (OR) of PAD (for uric acid > 6.1 mg/dl, OR = 4.31; 95% CI, 1.49-12.44). The remaining variables more strongly associated with PAD were: Heart rate >90 bpm (OR = 4.16; 95%CI, 1.62-10.65), pulse pressure in the upper quartile (≥ 54 mmHg) (OR = 3.82; 95%CI, 1.50-9.71), adherence to Mediterranean diet (OR = 2.73; 95% CI, 1.48-5.04), and former smoker status (OR = 2.04; 95%CI, 1.00-4.16).

CONCLUSIONS

Our results show the existence of a low prevalence of peripheral artery disease in a population aged 45-74 years. Serum uric acid, pulse pressure and heart rate >90 bpm were strongly associated with peripheral artery disease. The direct association between Mediterranean diet and peripheral artery disease that we have found should be evaluated through a follow-up study under clinical practice conditions.

Measures of chronic kidney disease and risk of incident peripheral artery disease: a collaborative meta-analysis of individual participant data

BACKGROUND

Some evidence suggests that chronic kidney disease is a risk factor for lower-extremity peripheral artery disease. We aimed to quantify the independent and joint associations of two measures of chronic kidney disease (estimated glomerular filtration rate [eGFR] and albuminuria) with the incidence of peripheral artery disease.

METHODS

In this collaborative meta-analysis of international cohorts included in the Chronic Kidney Disease Prognosis Consortium (baseline measurements obtained between 1972 and 2014) with baseline measurements of eGFR and albuminuria, at least 1000 participants (this criterion not applied to cohorts exclusively enrolling patients with chronic kidney disease), and at least 50 peripheral artery disease events, we analysed adult participants without peripheral artery disease at baseline at the individual patient level with Cox proportional hazards models to quantify associations of creatinine-based eGFR, urine albumin-to-creatinine ratio (ACR), and dipstick proteinuria with the incidence of peripheral artery disease (including hospitalisation with a diagnosis of peripheral artery disease, intermittent claudication, leg revascularisation, and leg amputation). We assessed discrimination improvement through c-statistics.

FINDINGS

We analysed 817 084 individuals without a history of peripheral artery disease at baseline from 21 cohorts. 18 261 cases of peripheral artery disease were recorded during follow-up across cohorts (median follow-up was 7·4 years [IQR 5·7-8·9], range 2·0-15·8 years across cohorts). Both chronic kidney disease measures were independently associated with the incidence of peripheral artery disease. Compared with an eGFR of 95 mL/min per 1·73 m2, adjusted hazard ratios (HRs) for incident study-specific peripheral artery disease was 1·22 (95% CI 1·14-1·30) at an eGFR of 45 mL/min per 1·73 m2 and 2·06 (1·70-2·48) at an eGFR of 15 mL/min per 1·73 m2. Compared with an ACR of 5 mg/g, the adjusted HR for incident study-specific peripheral artery disease was 1·50 (1·41-1·59) at an ACR of 30 mg/g and 2·28 (2·12-2·44) at an ACR of 300 mg/g. The adjusted HR at an ACR of 300 mg/g versus 5 mg/g was 3·68 (95% CI 3·00-4·52) for leg amputation. eGFR and albuminuria contributed multiplicatively (eg, adjusted HR 5·76 [4·90-6·77] for incident peripheral artery disease and 10·61 [5·70-19·77] for amputation in eGFR <30 mL/min per 1·73 m2 plus ACR ≥300 mg/g or dipstick proteinuria 2+ or higher vs eGFR ≥90 mL/min per 1·73 m2 plus ACR <10 mg/g or dipstick proteinuria negative). Both eGFR and ACR significantly improved peripheral artery disease risk discrimination beyond traditional predictors, with a substantial improvement prediction of amputation with ACR (difference in c-statistic 0·058, 95% CI 0·045-0·070). Patterns were consistent across clinical subgroups.

INTERPRETATION

Even mild-to-moderate chronic kidney disease conferred increased risk of incident peripheral artery disease, with a strong association between albuminuria and amputation. Clinical attention should be paid to the development of peripheral artery disease symptoms and signs in people with any stage of chronic kidney disease.

FUNDING

American Heart Association, US National Kidney Foundation, and US National Institute of Diabetes and Digestive and Kidney Diseases.

Electronegative low-density lipoprotein increases the risk of ischemic lower-extremity peripheral artery disease in uremia patients on maintenance hemodialysis

Electronegative low-density lipoprotein (LDL) has been shown to increase coronary artery disease risk in hemodialysis patients, but its effect on the risk of peripheral artery disease (PAD) remains unclear. We separated plasma LDL from 90 uremia patients undergoing hemodialysis into 5 subfractions (L1-L5) according to charge by using fast-protein liquid chromatography with an anion-exchange column and examined the distribution of L5-the most electronegative LDL subfraction-in total LDL (i.e. L5%). During a 5-year period, we followed up with these patients until the occurrence of ischemic lower-extremity PAD. During the follow-up period, ischemic lower-extremity PAD developed in 24.4% of hemodialysis patients. L5% was higher in hemodialysis patients in whom ischemic lower-extremity PAD occurred (3.03% [IQR, 2.36-4.54], n = 22) than in hemodialysis patients in whom PAD did not occur (1.13% [IQR, 0.90-1.83], n = 68) (p < 0.001). Furthermore, L5% significantly increased the adjusted hazard ratio of ischemic lower-extremity PAD (1.54 [95% CI, 1.14-2.10]) (p = 0.005). Flow-mediated dilation was negatively associated with L5% (p < 0.001). Additionally, in vivo experiments from mice showed that L5 compromised endothelium-dependent vascular relaxation through a nitric oxide-related mechanism. Our findings indicate that increased L5% may be associated with the occurrence of ischemic lower-extremity PAD in hemodialysis patients.

Assessment of Renal Function and Risk Factors for Chronic Kidney Disease in Patients With Peripheral Arterial Disease

Chronic kidney disease (CKD) and peripheral arterial disease (PAD) share common risk factors. We assessed renal function and the prevalence of CKD in patients with PAD and investigated the characteristics of the risk factors for CKD in this population. Renal function of 421 patients with PAD was evaluated. Among the participants, 194 (46.1%) patients had decreased estimated glomerular filtration rate (eGFR). The prevalence of CKD was much higher among patients with PAD. Hypertension (odds ratios [ORs] 2.156, 95% confidence interval [CI] 1.413-3.289, P < .001), serum uric acid (OR 3.794, 95% CI 2.220-6.450, P < .001), and dyslipidemia (OR 1.755, 95% CI 1.123-2.745, P = .014) were significantly associated with CKD and the independent risk factors for CKD in patients with PAD. CKD is common and has a high prevalence in a population with PAD. Patients with PAD may be considered as a high-risk population for CKD. Recognition and modification of risk factors for CKD might beneficially decrease CKD incidence and improve prognosis in patients with PAD.

Inflammation and elevated levels of fibroblast growth factor 23 are independent risk factors for death in chronic kidney disease

Inflammation is a consequence of chronic kidney disease (CKD) and is associated with adverse outcomes in many clinical settings. Inflammation stimulates production of fibroblast growth factor 23 (FGF23), high levels of which are independently associated with mortality in CKD. Few large-scale prospective studies have examined inflammation and mortality in patients with CKD, and none tested the interrelationships among inflammation, FGF23, and risk of death. Therefore, we conducted a prospective investigation of 3875 participants in the Chronic Renal Insufficiency Cohort (CRIC) study with CKD stages 2 to 4 to test the associations of baseline plasma interleukin-6, high-sensitivity C-reactive protein, and FGF23 levels with all-cause mortality, censoring at the onset of end-stage renal disease. During a median follow-up of 6.9 years, 550 participants died (20.5/1000 person-years) prior to end-stage renal disease. In separate multivariable-adjusted analyses, higher levels of interleukin-6 (hazard ratio per one standard deviation increase of natural log-transformed levels) 1.35 (95% confidence interval, 1.25-1.46), C-reactive protein 1.28 (1.16-1.40), and FGF23 1.45 (1.32-1.60) were each independently associated with increased risk of death. With further adjustment for FGF23, the risks of death associated with interleukin-6 and C-reactive protein were minimally attenuated. Compared to participants in the lowest quartiles of inflammation and FGF23, the multivariable-adjusted hazard ratio of death among those in the highest quartiles of both biomarkers was 4.38 (2.65-7.23) for interleukin-6 and FGF23, and 5.54 (3.04-10.09) for C-reactive protein and FGF23. Thus, elevated levels of interleukin-6, C-reactive protein, and FGF23 are independent risk factors for mortality in CKD.

Ankle Brachial Index and Subsequent Cardiovascular Disease Risk in Patients With Chronic Kidney Disease

BACKGROUND

The clinical implications of ankle-brachial index (ABI) cutpoints are not well defined in patients with chronic kidney disease (CKD) despite increased prevalence of high ABI attributed to arterial stiffness. We examined the relationship of ABI with cardiovascular disease (CVD) and all-cause mortality among CKD patients.

METHODS AND RESULTS

Three thousand six hundred twenty-seven participants without clinical peripheral artery disease (PAD) at baseline from the Chronic Renal Insufficiency Cohort Study were included. ABI was obtained per standard protocol and CVD events were confirmed by medical record adjudication. A U-shaped association of ABI with PAD, myocardial infarction (MI), composite CVD, and all-cause mortality was observed. Individuals with an ABI between 1.0 and <1.4 had the lowest risk of outcomes. Compared to participants with an ABI between 1.0 and <1.4, multiple-adjusted hazard ratios (95% confidence intervals) for those with an ABI of <0.9, 0.9 to <1.0, and ≥1.4 were 5.78 (3.57, 9.35), 2.76 (1.56, 4.88), and 4.85 (2.05, 11.50) for PAD; 1.67 (1.23, 2.29), 1.85 (1.33, 2.57), and 2.08 (1.10, 3.93) for MI; 1.51 (1.27, 1.79), 1.39 (1.15, 1.68), and 1.23 (0.82, 1.84) for composite CVD; and 1.55 (1.28, 1.89), 1.36 (1.10, 1.69), and 1.00 (0.62, 1.62) for all-cause mortality, respectively.

CONCLUSIONS

This study indicates that ABI <1.0 was related to risk of PAD, MI, composite CVD, and all-cause mortality whereas ABI ≥1.4 was related to clinical PAD. These findings suggest that ABI cutpoints of <1.0 or ≥1.4 for diagnosing PAD and ABI <1.0 for CVD risk stratification should be further evaluated among CKD patients.

Traditional and non-traditional risk factors for incident peripheral arterial disease among patients with chronic kidney disease

BACKGROUND

The risk of peripheral arterial disease (PAD) is higher in patients with chronic kidney disease (CKD) compared with those without. However, reasons for this increased risk are not fully understood.

METHODS

We studied risk factors for incident PAD among 3169 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study. Patients with CKD aged 21-74 years were recruited between 2003 and 2008 and followed for a median of 6.3 years. Incident PAD was defined as a new onset ankle-brachial index (ABI) of <0.9 or confirmed clinical PAD.

RESULTS

In a multivariate-adjusted model, older age, female sex, non-Hispanic Black, current smoking, diabetes, higher pulse pressure, lower high-density lipoprotein cholesterol, higher low-density lipoprotein cholesterol, and lower estimated glomerular filtration rate were significantly associated with the increased risk of incident PAD. After adjustment for these traditional risk factors as well as use of medications and CRIC Study clinic sites, the following baseline novel risk factors were significantly associated with risk of incident PAD [hazard ratio and 95% confidence interval (CI) for a one standard deviation (SD) higher level]: log[C-reactive protein (CRP)] (1.16, 1.06-1.25, P < 0.001), white blood cell count (1.09, 1.01-1.18, P = 0.03), fibrinogen (1.15, 1.06-1.26, P = 0.002), log(myeloperoxidase) (1.12, 1.03-1.23, P = 0.01), uric acid (0.88, 0.80-0.97, P = 0.01), glycated hemoglobin (1.16, 1.05-1.27, P = 0.003), log(homeostatic model assessment-insulin resistance) (1.21, 1.10-1.32, P < 0.001) and alkaline phosphatase (1.15, 1.07-1.24, P < 0.001).

CONCLUSIONS

Among patients with CKD, inflammation, prothrombotic state, oxidative stress, glycated hemoglobin, insulin resistance and alkaline phosphatase are associated with an increased risk of PAD, independent of traditional risk factors.

Early renal failure as a cardiovascular disease: Focus on lipoprotein(a) and prothrombotic state

Patients with renal failure are at increased risk of cardiovascular events even at the earliest stages of disease. In addition to many classic cardiovascular risk factors, many conditions that are commonly identified as emerging risk factors might contribute to occurrence of cardiovascular disease. Changes in circulating levels of many of these emerging risk factors have been demonstrated in patients with early stages of renal failure caused by different types of renal disease and have been associated with detection of cardiovascular complications. However, for most of these factors evidence of benefits of correction on cardiovascular outcome is missing. In this article, we comment on the role of lipoprotein(a) and prothrombotic factors as potential contributors to cardiovascular events in patients with early renal failure.

Pneumoconiosis increases the risk of peripheral arterial disease: a nationwide population-based study

This nationwide population-based retrospective cohort study was used to evaluate the association between pneumoconiosis and peripheral arterial disease (PAD). We identified 3374 patients with pneumoconiosis from the catastrophic illness registry who were newly diagnosed from 2000 to 2005; 13,496 patients without pneumoconiosis from Longitudinal Health Insurance Database 2000 (LHID2000) were randomly frequency matched according to sex, age, and index year and used as a nonpneumoconiosis group. Multivariate Cox proportional hazards regression was used to calculate adjusted hazard ratios (HRs) of PAD in the pneumoconiosis group compared with the nonpneumoconiosis group. The mean follow-up years were 7.44 years in the pneumoconiosis group and 8.17 years in the nonpneumoconiosis group. The incidence density rate of PAD was 1.25 times greater in the pneumoconiosis group than in the nonpneumoconiosis group (8.37 vs 6.70 per 1000 person-years). After adjusting for sex, age, and comorbidities, the adjusted HRs of PAD for the pneumoconiosis group were 1.30 (95% CI = 1.08-1.57), compared with the nonpneumoconiosis group. The combined impacts of patients with pneumoconiosis and diabetes, hyperlipidemia, hypertension, ischemic heart disease, chronic obstructive pulmonary disease, and asthma showed a significant by joint association with PAD risk compared with patients with no pneumoconiosis and no counterpart comorbidity. Patients with pneumoconiosis have an independently higher risk of developing PAD. Physicians should include pneumoconiosis in evaluating PAD risk.

Peripheral artery disease and chronic kidney disease: clinical synergy to improve outcomes

Persons with CKD are at a higher risk of developing peripheral artery disease (PAD) and its adverse health outcomes than individuals in the general population who have normal renal function. Classic atherosclerosis risk factors (eg, age, smoking, diabetes, hypertension, and hyperlipidemia) are common in patients with CKD, but CKD also imposes additional unique risk factors that promote arterial disease (eg, chronic inflammation, hypoalbuminemia, and a procalcific state). Current nephrology clinical practice is adversely affected by PAD diagnostic challenges, the complexities of managing 2 serious comorbid diseases, delayed vascular specialist referral, and slow PAD treatment initiation in patients with CKD. Persons with CKD are less likely to be provided recommended "optimal" PAD care. The knowledge that both limb and mortality outcomes are significantly worse in patients with CKD, especially those on dialysis, is not just a biologic fact but can serve as a care delivery call to action. Nephrologists can facilitate positive change. This article proposes that patients with PAD and CKD be strategically comanaged by care teams that encompass the skills to create and use evidence-based care pathways. This proposed collaborative multidisciplinary approach will include vascular medicine specialists, nephrologists, wound specialists, and mid-level providers. Just as clinical care quality metrics have served as the base for ESRD and acute MI quality improvement, it is time that such quality outcomes metrics be initiated for the large PAD-CKD population. This new system will identify and resolve key gaps in the current care model so that clinical outcomes improve within a cost-effective care frame for this vulnerable population.

Ankle-brachial blood pressure index predicts cardiovascular events and mortality in Japanese patients with chronic kidney disease not on dialysis

The ankle-brachial blood pressure index (ABPI) has been recognized to have a predictive value for cardiovascular (CV) events and mortality in general or dialysis populations. However, the associations between ABPI and those outcomes have not been fully investigated in predialysis patients. The present study aimed to clarify the relationships between ABPI and both CV events and mortality in Japanese chronic kidney disease (CKD) patients not on dialysis. In this prospective observational study, we enrolled 320 patients with CKD stages 3-5 who were not on dialysis. At baseline, ABPI was examined and a low ABPI was defined as <0.9. CV events and all-cause deaths were examined in each patient. A Cox proportional hazards model was applied to determine the risk factors for CV events, as well as for mortality from CV and all causes. The median follow-up period was 30 months. CV events occurred in 56 patients and all-cause deaths occurred in 48, including 20 CV deaths. Multivariate analysis showed that age and low ABPI were risk factors for CV events. It was demonstrated that age, a history of cerebrovascular disease and low ABPI were determined as independent risk factors for CV mortality. In addition, age, body mass index and low ABPI were independently associated with all-cause mortality. In patients with CKD, low ABPI during the predialysis period is independently associated with poor survival and CV events, suggesting the usefulness of measuring ABPI for predicting CV events and patient survival in CKD.

The associations of uric acid, cardiovascular and all-cause mortality in peritoneal dialysis patients

AIMS

To investigate whether uric acid (UA) is an independent predictor of cardiovascular (CV) and all-cause mortality in peritoneal dialysis (PD) patients after controlling for recognized CV risk factors.

METHODS

A total of 2264 patients on chronic PD were collected from seven centers affiliated with the Socioeconomic Status on the Outcome of Peritoneal Dialysis (SSOP) Study. All demographic and laboratory data were recorded at baseline. Multivariate Cox regression was used to calculate the hazard ratio (HR) of CV and all-cause mortality with adjustments for recognized traditional and uremia-related CV factors.

RESULTS

There were no significant differences in baseline characteristics between patients with (n = 2193) and without (n = 71) UA measured. Each 1 mg/dL of increase in UA was associated with higher all-cause mortality with 1.05(1.00∼1.10) of HR and higher CV mortality with 1.12 (1.05∼1.20) of HR after adjusting for age, gender and center size. The highest gender-specific tertile of UA predicted higher all-cause mortality with 1.23(1.00∼1.52) of HR and higher CV mortality with 1.69 (1.21∼2.38) of HR after adjusting for age, gender and center size. The predictive value of UA was stronger in patients younger than 65 years without CV disease or diabetes at baseline. The prognostic value of UA as both continuous and categorical variable weakened or disappeared after further adjusted for uremia-related and traditional CV risk factors.

CONCLUSIONS

The prognostic value of UA in CV and all-cause mortality was weak in PD patients generally, which was confounded by uremia-related and traditional CV risk factors.

Cystatin C: a strong marker for lower limb ischemia in Chinese type 2 diabetic patients?

OBJECTIVE

Cystatin C is growing to be an ideal indicator for renal function and cardiovascular events. The aim of this study was to investigate the relationship between serum cystatin C levels and peripheral arterial disease and to explore its diagnostic value for lower limb ischemia (LLI) in type 2 diabetic population.

METHODS

A total of 1609 T2DM patients were included in this cross-sectional study. Their clinical and biochemical characteristics, ankle-brachial index (ABI), carotid and lower extremity arterial ultrasound were detected. LLI was defined by ABI <0.9 and lower extremity arterial stenosis >50% by ultrasound examination. Patients were divided to two groups: with LLI and without. The risk factors of LLI were explored by binary logistic regression analysis.

RESULTS

The serum concentrations of cystatin C were 1.53±0.60 and 1.08±0.30 mg/L in patients with and without LLI, respectively. Binary logistic regression analysis showed that the significant risk factors were cystatin C (P = 0.007, OR = 5.081), the presence of hypertension (P = 0.011, OR = 3.527), age (P<0.001, OR = 1.181), GA (P = 0.002, OR = 1.089) and diabetes duration (P = 0.008, OR = 1.074). The prevalence of coronary artery disease, cerebral infarction and LLI increased with cystatin C (P<0.01), and the prevalence of LLI in patients with cystatin C >1.2 mg/L was much higher than other three quartile groups. Receiver operating characteristic curve analysis revealed the cut point of cystatin C for LLI was 1.2 mg/L. The risk of LLI dramatically increased in patients with cystatin C >1.2 mg/L (OR = 21.793, 95% confidence interval 10.046-47.280, P<0.001). After adjusting for sex, age, duration, HbA1c, GA and hypertension, its OR still remained 3.395 (95% confidence interval 1.335-8.634).

CONCLUSIONS

There was a strong and independent association between cystatin C and limb arterial disease in diabetic population, and cystatin C >1.2 mg/L indicated a great increased risk of LLI.

Fibrin(ogen) and thrombotic disease

Fibrinogen is an abundant plasma protein that, when converted to fibrin by thrombin, provides the main building blocks for the clot. Dys-, a-, and hypo-fibrinogenemias have been variably linked to a normal phenotype, bleeding or even thrombosis. Meanwhile, increased fibrinogen concentrations in the blood have been associated with risk for thrombosis. More recently, studies have focussed on abnormal fibrin structure as a cause for thrombosis. Fibrin clots that have high fiber density and increased resistance to fibrinolysis have been consistently associated with risk for thrombosis. Fibrin structure measurements can (i) provide an overall assessment of hemostatic capacity of a sample, (ii) include effects of thrombin generation and fibrinogen concentrations, (iii) include effects of fibrinogen mutations, polymorphisms, and modifications, and (iv) give an indication of clot mechanical strength and resistance to fibrinolysis. A fibrinogen splice variation of the γ-chain (γ') is discussed as a model for changes in fibrin structure in relation to thrombosis. Results from prospective studies on fibrin structure are awaited. Studies of fibrin formation under flow, interactions of fibrin with blood cells, the mechanical properties of the fibrin clot, and nanoscale/molecular characterization of fibrin formation are likely to expose new causal mechanisms for the role of fibrin in thrombotic disease. Future studies into the causality and mechanisms may lead to new opportunities using fibrin structure in the diagnosis or treatment of thrombosis.