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

Sex-Specific Analysis of Mid-Term Outcomes of Atherectomy-Assisted Endovascular Treatment in Severe Peripheral Arterial Disease

Background: Endovascular treatment of lower-extremity peripheral disease (PAD) is associated with higher complication rates and suboptimal outcomes in women. Atherectomy has shown favourable outcomes in calcified lesions, minimising the incidence of stent placement caused by recoil or flow-limiting dissection. To date, there are no published mid-term outcomes evaluating the performance of atherectomy differentiated by sex. This study aims to evaluate sex-specific outcomes and prognostic factors affecting the results of atherectomy-assisted endovascular treatment in severe PAD. Methods: A retrospective analysis was conducted at a single centre in Germany, initiated by physicians and not sponsored by industry, on patients presenting with Rutherford categories ranging from III to V and featuring de novo occlusive or stenotic lesions of the superficial femoral (SFA) and/or popliteal arteries. The intervention involved rotational atherectomy-assisted angioplasty utilising the Jetstream (Boston, US®) device. The point of interest of this study was postinterventional clinical improvement as well as mid-term outcomes, including primary patency, over a targeted 2-year follow-up period. Statistical analysis utilised Cox regression (survival analysis) to calculate hazard ratios according to sex category. Comparative survival analysis was performed using the log-rank test and visually represented through Kaplan-Meier curves. Risk factors associated with absence of clinical improvement were examined across both sex groups utilising the chi-square or Fisher exact test, as appropriate. Results: A total of 98 patients (103 limbs) were initially included, with >75% having moderate-to-severe lesion calcification (>50%). A total of 84 patients (97 limbs, 62 male and 35 female) proceeded to a 2-year follow-up (mean 16.4 months for males and 16.1 for females) after a successful index procedure. Age distribution, Rutherford class, diabetes, chronic kidney disease (CKD), target vessel, lesion type, and length were balanced among both groups. Similar primary patency rates, of 89% among female and 91% among male limbs, were observed (p = 0.471). Female patients exhibited a lower rate of clinical improvement based on the Rutherford scale in comparison to males (80.6% vs. 94.5%, p = 0.048). CDK was the only significant prognostic factor across pooled data (odds ratio for CKD: 15.15, p < 0.001). Conclusions: Rotational atherectomy showed comparably high rates of mid-term primary patency, with low rates of bailout stent placement. These findings highlight the beneficial use of atherectomy in female patients who are per se at risk for higher rates of complications during and after endovascular interventions.

Outcomes of peripheral artery disease and polyvascular disease in patients with end-stage kidney disease

OBJECTIVE

Patients with peripheral artery disease (PAD) and end-stage kidney disease are a high-risk population, and concomitant atherosclerosis in coronary arteries (CAD) or cerebral arteries (CVD) is common. The aim of the study was to assess long-term outcomes of PAD and the impact of coexistent CAD and CVD on outcomes.

METHODS

The United States Renal Data System was used to identify patients with PAD within 6 months of incident dialysis. Four groups were formed: PAD alone, PAD with CAD, PAD with CVD, and PAD with CAD and CVD. PAD-specific outcomes (chronic limb-threatening ischemia, major amputation, percutaneous/surgical revascularization, and their composite, defined as major adverse limb events [MALE]) as well as all-cause mortality, myocardial infarction, and stroke were studied.

RESULTS

The study included 106,567 patients (mean age, 71.2 years; 40.8% female) with a median follow-up of 546 days (interquartile range, 214-1096 days). Most patients had PAD and CAD (49.8%), 25.8% had PAD alone, and 19.2% had all three territories involved. MALE rate in patients with PAD was 22.3% and 35.0% at 1 and 3 years, respectively. In comparison to PAD alone, the coexistence of both CAD and CVD (ie, polyvascular disease) was associated with a higher adjusted rates of all-cause mortality (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.24-1.31), myocardial infarction (HR, 1.78; 95% CI, 1.69-1.88), stroke (HR, 1.66; 95% CI, 1.52,1.80), and MALE (HR, 1.07; 95% CI, 1.04-1.11).

CONCLUSIONS

Patients with end-stage kidney disease have a high burden of PAD with poor long-term outcomes, which worsen, in an incremental fashion, with the involvement of each additional diseased arterial bed.

The Double Burden: Deciphering Chronic Limb-Threatening Ischemia in End-Stage Renal Disease

BACKGROUND

Chronic limb-threatening ischemia (CLTI) in patients with end-stage renal disease (ESRD) poses significant challenges in clinical management due to its unique pathology and poor treatment outcomes. This review calls for a tailored classification and risk assessment for these patients to guide better revascularization choices with early minor amputation as a first-line strategy in advanced stages.

METHODS

This review consolidates key findings from recent literature on CLTI in ESRD, focusing on disease mechanisms, treatment options, and patient outcomes. It evaluates the literature to clarify the decision-making process for managing CLTI in ESRD.

RESULTS

CLTI in ESRD patients often results in worse clinical outcomes, such as nonhealing wounds, increased limb loss, and higher mortality rates. While the literature reveals ongoing debates regarding the optimal revascularization method, recent retrospective studies and meta-analyses suggest potential benefits of endovascular treatment (EVT) over open bypass surgery (OB) in reducing mortality and wound complications, with comparable amputation-free survival rates.

CONCLUSIONS

The selection of revascularization methods in ESRD patients with CLTI is complex, necessitating individualized strategies. The importance of early detection and timely intervention is critical to decelerate disease progression and improve revascularization outcomes. There is a shift in these treatment strategies toward less invasive endovascular procedures, acknowledging the limitations these patients face with open revascularization surgeries. Considering early minor amputations after revascularization could prevent worse consequences, reflecting a shift in the approach to managing CLTI in ESRD patients.

Chronic kidney disease and its association with cerebral small vessel disease in the general older hypertensive population

BACKGROUND

Cerebral small vessel disease can be identified using magnetic resonance imaging, and includes white matter hyperintensities, lacunar infarcts, cerebral microbleeds, and brain atrophy. Cerebral small vessel disease and chronic kidney disease share many risk factors, including hypertension. This study aims to explore an association between chronic kidney disease and cerebral small vessel disease, and also to explore the role of hypertension in this relationship.

METHODS

With a cross sectional study design, data from 390 older adults was retrieved from the general population study Good Aging in Skåne. Chronic kidney disease was defined as glomerular filtration rate < 60 ml/min/1,73m2. Associations between chronic kidney disease and magnetic resonance imaging markers of cerebral small vessel disease were explored using logistic regression models adjusted for age and sex. In a secondary analysis, the same calculations were performed with the study sample stratified based on hypertension status.

RESULTS

In the whole group, adjusted for age and sex, chronic kidney disease was not associated with any markers of cerebral small vessel disease. After stratification by hypertension status and adjusted for age and sex, we observed that chronic kidney disease was associated with cerebral microbleeds (OR 1.93, CI 1.04-3.59, p-value 0.037), as well as with cortical atrophy (OR 2.45, CI 1.34-4.48, p-value 0.004) only in the hypertensive group. In the non-hypertensive group, no associations were observed.

CONCLUSIONS

In this exploratory cross-sectional study, we observed that chronic kidney disease was associated with markers of cerebral small vessel disease only in the hypertensive subgroup of a general population of older adults. This might indicate that hypertension is an important link between chronic kidney disease and cerebral small vessel disease. Further studies investigating the relationship between CKD, CSVD, and hypertension are warranted.

Activation of the Aryl Hydrocarbon Receptor in Endothelial Cells Impairs Ischemic Angiogenesis in Chronic Kidney Disease

Rationale

Chronic kidney disease (CKD) is a strong risk factor for peripheral artery disease (PAD) that is associated with worsened clinical outcomes. CKD leads to accumulation of tryptophan metabolites that associate with adverse limb events in PAD and are ligands of the aryl hydrocarbon receptor (AHR) which may regulate ischemic angiogenesis.

Objectives

To test if endothelial cell-specific deletion of the AHR (AHRecKO) alters ischemic angiogenesis and limb function in mice with CKD subjected to femoral artery ligation.

Findings

Male AHRecKO mice with CKD displayed better limb perfusion recovery and enhanced ischemic angiogenesis compared to wildtype mice with CKD. However, the improved limb perfusion did not result in better muscle performance. In contrast to male mice, deletion of the AHR in female mice with CKD had no impact on perfusion recovery or angiogenesis. Using primary endothelial cells from male and female mice, treatment with indoxyl sulfate uncovered sex-dependent differences in AHR activating potential and RNA sequencing revealed wide ranging sex-differences in angiogenic signaling pathways.

Conclusion

Endothelium-specific deletion of the AHR improved ischemic angiogenesis in male, but not female, mice with CKD. There are sex-dependent differences in Ahr activating potential within endothelial cells that are independent of sex hormones.

Activation of the Aryl Hydrocarbon Receptor in Muscle Exacerbates Ischemic Pathology in Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) accelerates the development of atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the mechanisms underlying this pathobiology are ill-defined. Recent work has indicated that tryptophan-derived uremic solutes, which are ligands for AHR (aryl hydrocarbon receptor), are associated with limb amputation in PAD. Herein, we examined the role of AHR activation in the myopathy of PAD and CKD.

METHODS

AHR-related gene expression was evaluated in skeletal muscle obtained from mice and human PAD patients with and without CKD. AHRmKO (skeletal muscle-specific AHR knockout) mice with and without CKD were subjected to femoral artery ligation, and a battery of assessments were performed to evaluate vascular, muscle, and mitochondrial health. Single-nuclei RNA sequencing was performed to explore intercellular communication. Expression of the constitutively active AHR was used to isolate the role of AHR in mice without CKD.

RESULTS

PAD patients and mice with CKD displayed significantly higher mRNA expression of classical AHR-dependent genes (Cyp1a1, Cyp1b1, and Aldh3a1) when compared with either muscle from the PAD condition with normal renal function (P<0.05 for all 3 genes) or nonischemic controls. AHRmKO significantly improved limb perfusion recovery and arteriogenesis, preserved vasculogenic paracrine signaling from myofibers, increased muscle mass and strength, as well as enhanced mitochondrial function in an experimental model of PAD/CKD. Moreover, viral-mediated skeletal muscle-specific expression of a constitutively active AHR in mice with normal kidney function exacerbated the ischemic myopathy evidenced by smaller muscle masses, reduced contractile function, histopathology, altered vasculogenic signaling, and lower mitochondrial respiratory function.

CONCLUSIONS

These findings establish AHR activation in muscle as a pivotal regulator of the ischemic limb pathology in CKD. Further, the totality of the results provides support for testing of clinical interventions that diminish AHR signaling in these conditions.

Chronic activation of the aryl hydrocarbon receptor in muscle exacerbates ischemic pathology in chronic kidney disease

Chronic kidney disease (CKD) accelerates the development of atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the cellular and physiological mechanisms underlying this pathobiology are ill-defined. Recent work has indicated that tryptophan-derived uremic toxins, many of which are ligands for the aryl hydrocarbon receptor (AHR), are associated with adverse limb outcomes in PAD. We hypothesized that chronic AHR activation, driven by the accumulation of tryptophan-derived uremic metabolites, may mediate the myopathic condition in the presence of CKD and PAD. Both PAD patients with CKD and mice with CKD subjected to femoral artery ligation (FAL) displayed significantly higher mRNA expression of classical AHR-dependent genes ( Cyp1a1 , Cyp1b1 , and Aldh3a1 ) when compared to either muscle from the PAD condition with normal renal function ( P <0.05 for all three genes) or non-ischemic controls. Skeletal-muscle-specific AHR deletion in mice (AHR mKO ) significantly improved limb muscle perfusion recovery and arteriogenesis, preserved vasculogenic paracrine signaling from myofibers, increased muscle mass and contractile function, as well as enhanced mitochondrial oxidative phosphorylation and respiratory capacity in an experimental model of PAD/CKD. Moreover, viral-mediated skeletal muscle-specific expression of a constitutively active AHR in mice with normal kidney function exacerbated the ischemic myopathy evidenced by smaller muscle masses, reduced contractile function, histopathology, altered vasculogenic signaling, and lower mitochondrial respiratory function. These findings establish chronic AHR activation in muscle as a pivotal regulator of the ischemic limb pathology in PAD. Further, the totality of the results provide support for testing of clinical interventions that diminish AHR signaling in these conditions.

Kidney transplantation following iliac revascularization in severe atherosclerosis: a comparative study

BACKGROUND

Kidney transplantation (KT) has become the standard of care for patients with end-stage renal disease. However, as atherosclerosis progresses with time on dialysis, it causes increasing difficulties in implanting the graft. This is a comparative study analyzing complications and graft survival of recipients with iliac revascularization before transplantation.

METHODS

Between January 2006 and December 2015, 1691 kidney transplants were performed at our institution. We retrospectively analyzed eighteen patients with peripheral arterial disease (PAD) with the necessity of vascular revascularization before kidney transplantation to protect the inflow to the renal graft and to optimizing blood supply to the extremities. The primary endpoint included patient survival and graft survival. The secondary endpoints evaluate perioperative and early postoperative complication rates after kidney transplantation.

RESULTS

All patients enrolled in this study underwent two consecutive surgical procedures. No patient reported limb loss, and there was no additional perioperative morbidity or mortality related to the vascular procedure. Primary endpoints such as graft survival without dialysis and overall patient survival show 1-month survival of 100%, 1-year survival of 94.1%, and 5-year survival of 84.70%, respectively. One graft failure occurred 8 months after transplantation due to acute rejection, and there were two deaths over follow-up period due to myocardial infarction.

CONCLUSIONS

Vascular repair before kidney transplantation is safe, and results are suggestive that it prolongs graft survival. These promising results should encourage other centers to address vascular repair before the transplantation to optimize blood supply to the extremity and the future graft. Although, the interpretation of our results must be cautiously because of the small and heterogeneous sample size, and the limitations of retrospective study design. Prospective trials with larger study populations are needed to confirm the results of this study and to identify significant differences.

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.

Dietary Risk Factors and Eating Behaviors in Peripheral Arterial Disease (PAD)

Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.

The Impact of Chronic Kidney Disease on Mid-Term Outcomes after Revascularisation of Peripheral Arterial Occlusive Disease: Results from a Prospective Cohort Study

Objective: The current study aimed to determine the relationship between chronic kidney disease (CKD) and major 12-month outcomes for patients with in-hospital treatment for symptomatic peripheral arterial occlusive disease (PAOD). Methods: An analysis of the prospective longitudinal multicentric cohort study with 12-month follow-up was conducted including patients who underwent endovascular or open surgery for symptomatic PAOD at 35 German vascular centres (initial study protocol: NCT03098290). Severity of CKD was grouped into four stages combining information about the estimated glomerular filtration rate (eGFR) at baseline and dialysis dependency. Outcomes included overall mortality as well as the two composite endpoints of amputation or death, and of major cardiovascular events (MACE). 12-month incidences and adjusted hazard ratios were estimated using the Kaplan–Meier function and Cox proportional hazard models. Results: A total of 4354 patients (32% female, 69 years mean age, 68% intermittent claudication, 69% percutaneous endovascular revascularisation) were included and followed for 244 days in median. Thereof, 22% had any CKD and 5% had end stage kidney disease (ESKD) at baseline. The 12-month overall mortality rate was 3.6% (95% CI 2.3–4.9) with 96 events in the entire cohort: 147 were amputated or died (5.3%, 95% CI 5.2–5.3), and 277 had a MACE (9.5%, 95% CI 9.4–9.5). When compared with patients without kidney disease, ESKD was significantly associated with overall mortality (HR 1.9; 95% CI 1.1–3.5), amputation or death (HR 2.4; 95% CI 1.4–4.1), and MACE (HR 2.0; 95% CI 1.3–3.2). Conclusions: In the current study on mid-term outcomes after invasive revascularisation for symptomatic PAOD, one out of five patients suffered from any CKD while those few with ESKD had twice the odds of death, of amputation or death, and of major adverse cardiovascular events after twelve months. These results emphasise that concomitant CKD and its impact on outcomes should be considered by severity while mild and moderate grades should not lead to ineffectual treatment strategies.

Association of Chronic Kidney Disease with perioperative outcomes following acute lower limb revascularization

Background

There is a paucity of data examining the impact of advancing chronic kidney disease stages on outcomes following revascularization for acute limb ischemia. The present study examined the association of chronic kidney disease with in-hospital mortality, amputation, and resource utilization following revascularization for acute limb ischemia using a nationally representative cohort.

Methods

The 2016–2018 National Inpatient Sample was queried to identify all adult hospitalizations with lower extremity acute limb ischemia requiring surgical and/or endovascular interventions. Patients were grouped according to the presence of chronic kidney disease and its severity: no chronic kidney disease, chronic kidney disease 1–3 (chronic kidney disease stages 1 through 3), chronic kidney disease 4–5 (chronic kidney disease stages 4 through 5), and end-stage renal disease. Multivariable logistic and linear models were used to evaluate association of chronic kidney disease stage with outcomes of interest.

Results

Of an estimated 82,610 patients meeting study criteria, 14.8% had chronic kidney disease (chronic kidney disease 1–3: 63.4%, chronic kidney disease 4–5: 12.1%, end-stage renal disease: 24.5%). Compared to those with chronic kidney disease, chronic kidney disease patients were on average older, were more frequently female, and had a higher median Elixhauser Comorbidity Index. Increasing severity of chronic kidney disease was associated with a stepwise increase in unadjusted mortality rates (4.7% in no chronic kidney disease to 12.6% in end-stage renal disease, P < .001). Following risk adjustment, only end-stage renal disease was associated with increased odds of mortality (adjusted odds ratio 3.10, 95% confidence interval 2.28–4.22) and limb amputation (adjusted odds ratio 1.99, 95% confidence interval 1.59–2.48) compared to patients with no chronic kidney disease. Similarly, advancing chronic kidney disease stage conferred increased odds of prolonged length of stay and greater hospitalization costs.

Conclusion

Advanced renal dysfunction demonstrated inferior perioperative outcomes and greater health care expenditures in the study population. These findings imply that quality improvement efforts in acute limb ischemia revascularization should target patients with chronic kidney disease 4–5 and end-stage renal disease.

Arterial-renal Syndrome in Patients with ESRD, a New Disease Paradigm

Background

Patients with end-stage renal disease (ESRD) often present with an increased risk of cardiovascular disease. Conditions of compromised cardiovascular health such as atrial fibrillation (AFIB) and peripheral arterial disease (PAD) may alter biomarker levels in a way that reflects worsening ESRD. This study profiled biomarkers and laboratory parameters of endothelium dysfunction in patients with ESRD, categorized by additional AFIB and PAD conditions.

Methods

Citrated blood samples were collected from 95 patients with ESRD. Biomarker levels were measured from plasma samples using sandwich ELISAs, including tissue plasminogen activator (tPA), D-dimer, and nitrotyrosine. Lab parameters, including BUN, calcium, creatinine, parathyroid hormone, phosphate, alkaline phosphatase, ferritin, transferrin, and total iron capacity, and patient comorbidities were obtained from patient medical records. The comorbidities were determined through provider notes, and evidence of applicable testing.

Results

14.89% of patients were found to have atrial fibrillation (n = 14), 30.85% of patients were found to have peripheral arterial disease (n = 29), and 6.38% of patients were found to have both peripheral arterial disease and atrial fibrillation (n = 6). When compared to patients with only ESRD, patients with ESRD and PAD showed elevated levels of D-Dimer (p = .0314) and nitrotyrosine (p = .0330). When compared to patients with only ESRD, patients with atrial fibrillation showed elevated levels of D-Dimer (p = .0372), nitrotyrosine (p = .0322), and tPA (p = .0198).

Conclusion

When compared to patients with just ESRD, patients with concomitant PAD had elevated levels of Nitrotyrosine and D-dimer; while patients with concomitant Afib had elevated levels of nitrotyrosine, D-dimer, as well as tPA.

Safety and Efficacy of Hybrid Angiography in Chronic Lower Extremity Ischemia Patients at Risk of Contrast-Induced Acute Kidney Injury

AIM

The aim of the study was to assess the feasibility and safety of hybrid angiography consisting of carbon dioxide (CO₂) angiography supplemented by small doses of iodinated contrast medium (ICM) in the endovascular treatment of chronic limb threatening ischemia (CLTI) patients with pre-existing chronic kidney disease (CKD).

PATIENTS AND METHODS

This prospective study comprised all non-dialysis-dependent CKD patients presenting for endovascular management of CLTI. All endovascular interventions were done using CO₂ as a contrast medium whether alone or supplemented by ICM (hybrid angiography) to treat unilateral arterial steno-occlusive lesions of iliac, femoropopliteal, or BTK arteries. Study outcomes included feasibility of the device, technical success, and freedom from contrast-induced acute kidney injury (CI-AKI), renal replacement therapy, and CO₂ angiography-related complications.

RESULTS

A total of 206 CKD patients underwent endovascular intervention using CO₂ only as a contrast medium (159 patients, 77.2%), or hybrid CO₂-ICM angiography (47 patients, 22.8%). The overall technical success was 95.6%. Patients were followed up for a mean period of 17.9 ± 4.6 months. The mean volumes of CO₂, and ICM consumption were 200.7 ± 95.1 mL, and 11.8 ± 4.4 mL, respectively. The mean procedural, and fluoroscopy times were 95.6 ± 12.5 and 49.5 ± 10.8 minutes, respectively. BTK lesions were significantly associated with the need for hybrid angiography (P = <.0001). The mean pre- and postoperative serum creatinine levels were comparable (P = .08). Two patients (4.3%) showed transient manifestations of CI-AKI, but neither required renal replacement therapy. No statistically significant differences were encountered between the two study groups regarding procedure outcomes.

CONCLUSION

Hybrid CO₂-ICM angiography is safe, feasible, effective, and a fairly simple alternative during endovascular interventions to treat chronic lower extremity ischemia. Using supplemental small volumes of ICM to overcome the suboptimal images generated by CO₂ alone does not jeopardize the renal functions in CKD patients.

Association of Plasma Branched-Chain and Aromatic Amino Acids with Reduction in Kidney Function Evaluated in Apparently Healthy Adults

The published literature on the association of circulatory branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) with reduced kidney function is inconsistent or conflicting. Clarification of it might help to better understand the underlying pathophysiology and to determine potential biomarkers for early detection and evaluation of kidney function decline. Our main purpose was to explore and clarify the potential relationships of individual BCAAs and AAAs with estimated glomerular filtration rate (eGFR) decline. We included the data from 2804 healthy subjects and categorized them into three groups based on eGFR tertiles. The associations between individual amino acids and eGFR were explored by covariate-adjusted logistic regression models. There was a progressive increase in the concentrations of BCAAs and AAAs from the upper to the lower tertiles. We revealed significant positive associations of isoleucine, leucine, and phenylalanine with lower tertiles of eGFR in the adjusted models (p < 0.01-0.001). The findings hold a promising potential of using plasma isoleucine, leucine, and phenylalanine levels for evaluation of kidney function decline. Future longitudinal studies should investigate the causal association between altered levels of these amino acids and impaired kidney function and also the utility of the former as potential biomarkers for evaluating the risk and early detection of the latter.

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.

Peripheral Vascular Disease and Kidney Transplant Outcomes: Rethinking an Important Ongoing Complication

Peripheral vascular disease (PVD) is highly prevalent in patients on the waiting list for kidney transplantation (KT) and after transplantation and is associated with impaired transplant outcomes. Multiple traditional and nontraditional risk factors, as well as uremia- and transplant-related factors, affect 2 processes that can coexist, atherosclerosis and arteriosclerosis, leading to PVD. Some pathogenic mechanisms, such as inflammation-related endothelial dysfunction, mineral metabolism disorders, lipid alterations, or diabetic status, may contribute to the development and progression of PVD. Early detection of PVD before and after KT, better understanding of the mechanisms of vascular damage, and application of suitable therapeutic approaches could all minimize the impact of PVD on transplant outcomes. This review focuses on the following issues: (1) definition, epidemiological data, diagnosis, risk factors, and pathogenic mechanisms in KT candidates and recipients; (2) adverse clinical consequences and outcomes; and (3) classical and new therapeutic approaches.

The Impact of Chronic Kidney Disease on Peripheral Artery Disease and Peripheral Revascularization

Chronic kidney disease (CKD) is a clinical condition characterized by high morbidity and mortality. Globally, CKD is also increasing in prevalence and incidence. The two principal kidney measures namely estimated glomerular filtration rate (eGFR) and albuminuria have been found to be predictors of renal and cardiovascular (CV) endpoints including peripheral artery disease (PAD). The prevalence of PAD was increased in CKD patients and, particularly, in patients with more severe CKD stages. Despite the fact that revascularization strategies are suitable in CKD patients in similar fashion to non-CKD patients, few CKD patients underwent these procedures. In fact, if it is true that revascularization improves prognosis in PAD patients irrespective of baseline eGFR, it was also demonstrated that CKD patients, who underwent revascularization, were at higher risk for amputations, mortality, re-intervention and perioperative complications. With the present review article, we have examined the association between CKD, PAD and peripheral revascularization highlighting data about epidemiology, pathophysiologic mechanisms, and results from previous observational and intervention studies. We have also examined the future perspectives and challenges of research around the association between CKD and PAD.

Central and peripheral arterial diseases in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) affects about 10% of all populations worldwide, with about 2 million people requiring dialysis. Although patients with CKD are at high risk of cardiovascular disease and events, they are often underrepresented or excluded in clinical trials, leading to important knowledge gaps about how to treat these patients. KDIGO (Kidney Disease: Improving Global Outcomes) convened the fourth clinical Controversies Conference on the heart, kidney and vasculature in Dublin, Ireland, in February 2020, entitled Central and Peripheral Arterial Diseases in Chronic Kidney Disease. A global panel of multidisciplinary experts from the fields of nephrology, cardiology, neurology, surgery, radiology, vascular biology, epidemiology, and health economics attended. The objective was to identify key issues related to the optimal detection, management, and treatment of cerebrovascular diseases, central aortic disease, renovascular disease, and peripheral artery disease in the setting of CKD. This report outlines the common pathophysiology of these vascular processes in the setting of CKD, describes best practices for their diagnosis and management, summarizes areas of uncertainty, addresses ongoing controversial issues, and proposes a research agenda to address key gaps in knowledge that, when addressed, could improve patient care and outcomes.

SNF472: mechanism of action and results from clinical trials

PURPOSE OF REVIEW

Vascular calcification (VC) is associated with increased cardiovascular event rates, particularly in patients with end-stage kidney disease (ESKD). Dysregulated mineral metabolism and inflammation have been shown to promote VC, however, treatment options targeting VC specifically are not available. This review outlines the pathophysiological mechanisms contributing to VC in ESKD and describes recent studies evaluating the effects of the first-in-class inhibitor of VC, SNF472.

RECENT FINDINGS

SNF472 directly inhibits calcium phosphate crystal formation and aggregation. SNF472 has completed early phase clinical trials with a favourable safety profile and Phase 2 clinical trial data have shown attenuation of coronary artery and aortic valve calcification in patients receiving hemodialysis.

SUMMARY

Therapeutic agents that directly target VC may prevent the multiple complications associated with dystrophic calcification in patients with ESKD.

Estimated Glomerular Filtration Rate as a Predictor of Restenosis After Carotid Stenting Using First-Generation Stents

This study evaluated the impact of the baseline estimated glomerular filtration rate (eGFR) on clinical and angiographic outcomes and long-term in-stent restenosis (ISR) rates in patients undergoing elective carotid artery stenting (CAS) procedures. Consecutive patients who underwent CAS were retrospectively enrolled (n = 456). At the end of 3 years of follow-up, patients who had died or were lost follow-up were excluded from the study and a final analysis was performed using data from the remaining 405 patients. The study population (n = 405) was divided into 3 tertiles based on the tertile values of the eGFR level (T1, T2, and T3); then, clinical and procedural characteristics and 3-year ISR rates were compared between the groups. An ISR of 50% was detected in 49 (12%) surviving patients. The 3-year ISR was higher among patients with the lowest eGFR values (T1) by 3.7 times (95% CI: 2.01-11.38) than that among patients with the highest eGFR values (T3). These significant relationships persisted following adjustment for confounders. A lower baseline eGFR level was significantly associated with an increased ISR rate. Decreased renal function may be a predictor of ISR after CAS using first-generation stents.

Comparison of Pre-Amputation Evaluation in Patients with and without Chronic Kidney Disease

INTRODUCTION

Patients with chronic kidney disease (CKD) and peripheral artery disease (PAD) are more likely to undergo lower extremity amputation than patients with preserved kidney function. We sought to determine whether patients with CKD were less likely to receive pre-amputation care in the 1-year prior to lower extremity amputation compared to patients without CKD.

METHODS

We conducted a retrospective observational study of patients with PAD-related lower extremity amputation between January 2014 and December 2017 using a large commercial insurance database. The primary exposure was CKD identified using billing codes and laboratory values. The primary outcomes were receipt of pre-amputation care, defined as diagnostic evaluation (ankle-brachial index, duplex ultrasound, and computed tomographic angiography), specialty care (vascular surgery, cardiology, orthopedic surgery, and podiatry), and lower extremity revascularization in the 1-year prior to amputation. We conducted separate logistic regression models to estimate the adjusted odds ratio (aOR) and 95% confidence intervals (CIs) among patients with and without CKD. We assessed for effect modification by age, sex, Black race, and diabetes status.

RESULTS

We identified 8,554 patients with PAD-related amputation. In fully adjusted models, patients with CKD were more likely to receive diagnostic evaluation (aOR 1.30; 95% CI 1.17-1.44) and specialty care (aOR 1.45, 95% CI 1.27-1.64) in the 1-year prior to amputation. There was no difference in odds of revascularization by CKD status (aOR 1.03, 0.90-1.19). Age, sex, Black race, and diabetes status did not modify these associations.

DISCUSSION/CONCLUSION

Patients with CKD had higher odds of receiving diagnostic testing and specialty care and similar odds of lower extremity revascularization in the 1-year prior to amputation than patients without CKD. Disparities in access to pre-amputation care do not appear to explain the higher amputation rates seen among patients with CKD.

Pre-operative ankle-brachial index for cardiovascular risk assessment in simultaneous pancreas-kidney transplant recipients: a simple and elegant strategy!

Background

Patients with insulin-dependent diabetes mellitus type 1 (IDDM1) and end-stage kidney disease (ESKD) undergoing simultaneous pancreas kidney transplantation (SPKT) are a population with diffuse atherosclerosis and elevated risk of cardio- and cerebrovascular morbidity and mortality. We aimed to investigate the feasibility of preoperative screening for peripheral arterial disease (PAD), specifically ankle-brachial index (ABI) testing, to predict peri- and postoperative outcomes in SPKT recipients.

Methods

Medical data (2000–2016) from all patients with IDDM and ESKD undergoing SPKT at our transplant center were retrospectively analyzed. The correlation between PAD (defined by an abnormal ABI before SPKT and graft failure and mortality rates as primary end points, and the occurrence of acute myocardial infarction, cerebrovascular and peripheral vascular complications as secondary end points were investigated after adjustment for known cardiovascular risk factors.

Results

Among 101 SPKT recipients in our transplant population who underwent structured physiological arterial studies, 17 patients (17%) were diagnosed with PAD before transplantation. PAD, as defined by a low ABI index, was an independent and significant predictor of death (HR, 2.99 (95% CI 1.00–8.87), p = 0.049) and pancreas graft failure (HR, 4.3 (95% CI 1.24–14.91), p = 0.022). No significant differences were observed for kidney graft failure (HR 1.85 (95% CI 0.76–4.50), p = 0.178). In terms of the secondary outcomes, patients with PAD were more likely to have myocardial infarction, stroke, limb ischemia, gangrene or amputation (HR, 2.90 (95% CI 1.19–7.04), p = 0.019).

Conclusions

Pre-transplant screening for PAD and cardiovascular risk factors with non-invasive ABI testing may help to reduce perioperative complications in high-risk patients. Future research on long-term outcomes might provide more in depth insights in optimal treatment strategies for PAD among SPKT recipients.

Outcomes of Lower Extremity Endovascular Revascularization: Potential Predictors and Prevention Strategies

Peripheral artery disease (PAD) is a manifestation of atherosclerosis, which may affect arteries of the lower extremities. The most dangerous PAD complication is chronic limb-threatening ischemia (CLTI). Without revascularization, CLTI often causes limb loss. However, neither open surgical revascularization nor endovascular treatment (EVT) ensure long-term success and freedom from restenosis and revascularization failure. In recent years, EVT has gained growing acceptance among all vascular specialties, becoming the primary approach of revascularization in patients with CLTI. In clinical practice, different clinical outcomes after EVT in patients with similar comorbidities undergoing the same procedure (in terms of revascularization technique and localization of the disease) cause unsolved issues that need to be addressed. Nowadays, risk management of revascularization failure is one of the major challenges in the vascular field. The aim of this literature review is to identify potential predictors for lower extremity endovascular revascularization outcomes and possible prevention strategies.

Clinical outcomes of patients with and without chronic kidney disease undergoing endovascular revascularization of infrainguinal peripheral artery disease: Insights from the XLPAD registry

OBJECTIVES

The purpose of the present study was to define clinical outcomes of chronic kidney disease (CKD) patients undergoing endovascular revascularization of infrainguinal peripheral artery disease (PAD).

BACKGROUND

CKD is an established predictor of advanced PAD. However, clinical outcomes for these patients following endovascular revascularization remain inadequately defined.

METHODS

Using the ongoing multicenter Excellence in Peripheral Artery Disease (XLPAD) registry (NCT01904851), we analyzed all-cause death, target limb amputation, and need for repeat revascularization for patients with and without CKD undergoing infrainguinal endovascular revascularization between the years 2005 and 2018.

RESULTS

Of 3,699 patients, 15.1% (n = 559) had baseline CKD. CKD patients had significantly higher incidence of heavily calcified lesions (48.4% vs. 38.1%, p < .001) and diffuse disease (66.9% vs. 61.5%, p = .007). Kaplan-Meier analysis showed significant differences between CKD and non-CKD patient outcomes at 12 months for freedom from target limb amputation (79.9% vs. 92.7%, p < .001) and all-cause death (90.1% vs. 97.6%, p < .001). However, freedom from target vessel revascularization was similar between the groups. After adjusting for baseline comorbidities in the CKD and non-CKD groups, the hazard ratios for target limb amputation and death at 12 months were 2.28 (95% confidence interval or CI 1.25-4.17, p < .001) and 4.38 (95% CI 2.58-7.45, p < .001), respectively.

CONCLUSIONS

Following endovascular revascularization for infrainguinal PAD, CKD was an independent predictor of all-cause death and target limb amputation at 12 months.

Chronic kidney disease as a cardiovascular risk factor

: Chronic kidney disease (CKD) is a public health threat with impact in cardiovascular risk. All forms of cardiovascular disease and mortality are more common in CKD. Treatment of cardiovascular risk factors, hypertension, dyslipidemia and diabetes is essential for cardiovascular and kidney protection. CKD is a marker of high or very high cardiovascular risk and its presence require early treatment and specific goals. Lifestyle is a pivotal factor, stopping smoking, reducing weight in the overweight or obese, starting regular physical exercise and healthy dietary pattern are recommended. Office BP should be lowered towards 130/80 mmHg or even lower if tolerated with sodium restriction and single pill combination, including angiotensin system blocker. Out-of-office BP monitoring, mainly 24-h assessment, is recommended. Diabetes requires treatment from the moment of diagnosis, but prediabetes benefits with lifestyle changes and metformin in patients stage 2 and 3a. iSGLT2 and GLP-1RA are initially recommended in T2D patients with high or very high cardiovascular risk. Concerning dyslipidemia, for patients in stage 4, LDL-C 55 mg/dl or less (1.4 mmol/l) and an LDL-C reduction of 50% or less from baseline is recommended. In stage 3, LDL-C goal is 70 mg/dl or less (1.8 mmol/l) and an LDL-C. reduction of at least 50% from baseline. Statins are the lipid-lowering therapy of choice with or without ezetimibe. Higher doses of statins are required as GFR declines. Available evidence suggests that combined PCSK9 inhibitors with maximally tolerated dose of statins may have an emerging role in treatment of dyslipidemia in CKD patients.

Implications of Renal Disease in Patients Undergoing Peripheral Arterial Interventions

Since the first peripheral endovascular intervention (PVI) in 1964, the procedure's technical aspects and indications have advanced significantly. Today, endovascular procedures span the spectrum of presentations from acute limb ischemia to critical limb ischemia and symptomatic limiting claudication. Goals of PVI remain restoring limb perfusion, minimizing rates of amputation and mortality, and sparing the need for the high-risk bypass surgery. Unfortunately, there are no large randomized controlled trials that address the optimal approach to peripheral arterial disease revascularization in chronic kidney disease (CKD) patients.

Carbon dioxide-angiography for patients with peripheral arterial disease at risk of contrast-induced nephropathy

Patients with peripheral arterial disease (PAD) and critical limb ischemia are at risk for limb amputation and require urgent management to restore blood flow. Patients with PAD often have several comorbidities, including chronic kidney disease, diabetes mellitus, and hypertension. Diagnostic and interventional angiography using iodinated contrast agents provides excellent image resolution but can be associated with contrast-induced nephropathy (CIN). The use of carbon dioxide (CO₂) as a contrast agent reduces the volume of iodine contrast required for angiography and reduces the incidence of CIN. However, CO₂ angiography has been underutilized due to concerns regarding safety and image quality. Modern CO₂ delivery systems with advanced digital subtraction angiography techniques and hybrid angiography have improved imaging accuracy and reduced the incidence of CIN. Awareness of the need for optimal imaging conditions, contraindications, and potential complications have improved the safety of CO₂ angiography. This review aims to highlight current technological advances in the delivery of CO₂ in vascular angiography for patients with PAD and critical limb ischemia, which result in limb preservation while preventing kidney damage.

Lipoprotein-associated phospholipase A2 predicts lower limb ischemia in hemodialysis subjects

Hemodialyzed patients (HD) have high prevalence of peripheral arterial disease. In the general population, lipoprotein-associated phospholipase A2 (Lp-PLA² ) is associated with peripheral arterial disease but no data are available for renal subjects. The aim of this study was to evaluate the relationship between Lp-PLA₂ and lower limb ischemia among dialyzed patients. One hundred and two dialyzed subjects, with median (IQR) age of 71 (59-78) years, enrolled in June 2013 and followed until June 2018, were investigated for Lp-PLA₂ activity and the occurrence of peripheral arterial disease and lower limb ischemia. The median (IQR) levels of Lp-PLA₂ were 184 nmol/min/mL (156.5-214.5). The 43 HD patients with abnormal Lp-PLA₂ activity (>194 nmol/min/mL) had higher levels of total and LDL-cholesterol, ApoB/A1 ratio, and higher occurrence of lower limb ischemia during the follow up (44% vs 17%, P = .003). In multivariate analysis, Lp-PLA₂ activity (P = .018) and diabetes (P < .001) were independently associated with time to lower limb ischemia, and when the presence of previous PAD was added to the multivariate model, only presence of previous PAD (P < .001) and Lp-PLA₂ (P = .003) remained associated. Lp-PLA₂ is an independent predictor of lower limb ischemia in dialyzed patients.