Combined Impact of Chronic Kidney Disease and Contrast Induced Acute Kidney Injury on Long-term Outcomes in Patients with Acute Lower Limb Ischaemia

Impact of Chronic Kidney Disease on In-Hospital Outcomes of Hospitalizations With Acute Limb Ischemia Undergoing Endovascular Therapy

PURPOSE

Studies on outcomes related to endovascular treatment (EVT) in advanced stages of chronic kidney disease (CKD) and end-stage renal disease (ESRD) among hospitalizations with acute limb ischemia (ALI) are limited.

METHODS

The Nationwide Inpatient Sample was quarried from October 2015 to December 2017 to identify the hospitalizations with ALI and undergoing EVT. The study population was subdivided into 3 groups based on their CKD stages: group 1 (No CKD, stage I, stage II), group 2 (CKD stage III, stage IV), and group 3 (CKD stage V and ESRD). The primary outcome was all-cause in-hospital mortality.

RESULTS

A total of 51 995 hospitalizations with ALI undergoing EVT were identified. The in-hospital mortality was significantly higher in group 2 (OR = 1.17; 95% CI 1.04 - 1.32, p=0.009) and group 3 (OR = 3.18; 95% CI 2.74-3.69, p<0.0001) compared with group 1. Odds of minor amputation, vascular complication, atherectomy, and blood transfusion were higher among groups 2 and 3 compared with group 1. Group 2 had higher odds of access site hemorrhage compared with groups 1 and 3, whereas group 3 had higher odds of major amputation, postprocedural infection, and postoperative hemorrhage compared with groups 1 and 2. Besides, groups 2 and 3 had lower odds of discharge to home compared with group 1. Finally, the length of hospital stay and cost of care was significantly higher with the advancing CKD stages.

CONCLUSION

Advanced CKD stages and ESRD are associated with higher mortality, worse in-hospital outcomes and higher resource utilization among ALI hospitalizations undergoing EVT.

CLINICAL IMPACT

Current guidelines are not clear for the optimum first line treatment of acute limb ischemia, especially in patients with advanced kidney disease as compared to normal/mild kidney disease patients. We found that advanced kidney disease is a significant risk factor for worse in-hospital morbidity and mortality. Furthermore, patients with acute limb ischemia and advanced kidney disease is associated with significantly higher resource utilization as compared to patients with normal/mild kidney disease. This study suggests shared decision making between treating physician and patients when considering endovascular therapy for the treatment of acute limb ischemia in patients with advanced kidney disease.

NGAL as Biomarker of Clinical and Subclinical Damage of Kidney Function after Coronary Angiography

Contrast-induced acute kidney injury (CI-AKI) is a serious complication after angiographic examinations in cardiology. Diagnosis may be delayed based on standard serum creatinine, and subclinical forms of kidney damage may not be detected at all. In our study, we investigate the clinical use in these directions of a “damage”-type biomarker—neutrophil gelatinase-associated lipocalin (NGAL). Among patients with a high-risk profile undergoing scheduled coronary angiography and/or angioplasty, plasma NGAL was determined at baseline and at 4th and 24th h after contrast administration. In the CI-AKI group, NGAL increased significantly at the 4th hour (Me 109.3 (IQR 92.1–148.7) ng/mL versus 97.6 (IQR 69.4–127.0) ng/mL, p = 0.006) and at the 24th hour (Me 131.0 (IQR 81.1–240.8) ng/mL, p = 0.008). In patients with subclinical CI-AKI, NGAL also increased significantly at the 4th hour (Me 94.0 (IQR 75.5–148.2) ng/mL, p = 0.002) and reached levels close to those in patients with CI-AKI. Unlike the new biomarker, however, serum creatinine did not change significantly in this group. The diagnostic power of NGAL is extremely good—AUC 0.847 (95% CI: 0.677–1.000; p = 0.001) in CI-AKI and AUC 0.731 (95% CI: 0.539–0.924; p = 0.024) in subclinical CI-AKI. NGAL may be a reliable biomarker for the early diagnosis of clinical and subclinical forms of renal injury after contrast angiographic studies.

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.

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.

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.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 2

This is Part 2 of a narrative review summarizing the literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures, focusing on peripheral artery disease (PAD) and renal artery stenosis (RAS). Part 1 discussed CIN in relation to aortic aneurysms and carotid stenosis. We comment on the incidence, biomarkers, risk factors, and consequences of CIN in patients with PAD or RAS, as well as on strategies to prevent CIN. Future perspectives in the field of CIN in relation to non-cardiac vascular procedures are also considered.

Strategies to Minimize Iodinated Contrast Volume in Patients with Chronic Kidney Disease Undergoing Peripheral Vascular Interventions

Peripheral vascular interventions (PVI) utilize iodinated contrast medium (ICM) to visualize intravascular lesions and guide therapy. The use of ICM carries a risk of postcontrast acute kidney injury (PC-AKI), which is increased in the elderly and in patients with chronic kidney disease (CKD). Furthermore, the risk of PC-AKI increases with the volume of ICM used. This paper reports a 94-year-old patient with CKD stage 4 who presented with chronic limb threatening ischemia. He underwent successful endovascular revascularization using a combination of CO₂ and dilute ICM (total volume = 6.5 mL). The case demonstrates strategies to minimize ICM during PVIs.

Comparison Between Below Knee Contrast Enhanced Tomographic 3D Ultrasound and CT, MR or Catheter Angiography for Peripheral Artery Imaging

OBJECTIVE

Clear imaging of below knee and foot arteries is essential to plan distal reconstructions. Contrast enhanced tomographic 3D ultrasound (CEtUS) is novel and entirely safe with no exposure to ionising radiation or nephrotoxic contrast. In the present study, inter- and intra-observer agreement of CEtUS was calculated, and compared with below knee angiography.

METHODS

In the same week as computed tomography, magnetic resonance or catheter angiography, CEtUS was performed using intravenous 1.2 mL bolus injections of Sonovue with a maximum of 5 mL administered per patient. CEtUS was reported by a vascular scientist blinded to the angiograms reported by a consultant radiologist. Images were compared using a modified Society of Vascular Surgery (SVS) runoff score.

RESULTS

Of the 181 patients recruited with peripheral arterial disease, 20 were excluded from analysis as they withdrew consent, could not be cannulated, or their images were non-diagnostic. In the remaining 161 patients, there were 175 comparative patient images split into two groups: 81 had calf imaging and 94 had pedal imaging representing 405 and 198 imaged arteries, respectively. Weighted quadratic kappa/ICC values for intra- and inter-observer agreement were excellent (κ/ICC = 0.83 to 0.95) and had narrow confidence intervals in both groups. When comparing angiography and CEtUS, weighted quadratic κ/ICC agreement was moderate with acceptable confidence intervals in both groups (Calf κ/ICC = 0.54; Pedal κ/ICC = 0.53). Agreement decreased from popliteal to pedal vessels as diameter decreased. Agreement between CEtUS and digital subtraction angiography was best, and computed tomography angiography the weakest.

CONCLUSION

CEtUS is a novel imaging modality with strong observer agreement that achieves clear peripheral and foot images without ionising radiation exposure or nephrotoxic X-ray contrast media. CEtUS enhances visualisation of runoff vessels, which may play a role in planning of limb salvage or targeted assessment.

Postcontrast Acute Kidney Injury after Peripheral Vascular Interventions in Kidney Transplant Recipients

BACKGROUND

Postcontrast acute kidney injury (PC-AKI) is a feared complication of peripheral vascular interventions (PVIs), associated with increased mortality. Whether kidney transplant recipients (KTRs) are at increased risk of PC-AKI after PVI is unknown. This study analyzes the perioperative outcomes of KTR following PVI, with emphasis on the incidence and risk factors for PC-AKI.

METHODS

The Vascular Quality Initiative files for PVI (2010-2018) were reviewed. Patients on dialysis were excluded. PC-AKI was defined by Vascular Quality Initiative as creatinine increase ≥0.5 mg/dL or new dialysis requirement. Characteristics of KTR and patients without kidney transplant were compared, and propensity score matching used to control for differences in baseline features. Multivariable logistic regression was used to define risk factors for PC-AKI, and survival was compared using Kaplan-Meier analysis.

RESULTS

A total of 58,014 procedures were analyzed, including 641 (1%) procedures for KTR. The incidence of PC-AKI in KTR was 2.8% compared with 0.9% in patients without kidney transplants. Baseline warfarin use (odds ratio [OR] = 4.7) and poor allograft function (OR = 4.0) were significantly associated with increased risk for PC-AKI in KTR. Compared with a matched group of patients without kidney transplant, KTR had similar risk of PC-AKI and were more likely to develop postop myocardial infarction (OR = 4.3) but had lower in-hospital mortality (OR = 0.22).

CONCLUSIONS

The incidence of PC-AKI in KTR is higher than the overall population undergoing PVI but is not elevated compared with propensity-matched patients without kidney transplant. PVI for peripheral artery disease in KTR is safe and associated with acceptable perioperative and long-term survival.

Endovascular Versus Surgical Revascularization for Acute Limb Ischemia: A Propensity-Score Matched Analysis

BACKGROUND

The optimal revascularization strategy for acute limb ischemia (ALI) remains unclear, and contemporary comparative effectiveness data on endovascular versus surgical revascularization are lacking.

METHODS

We used the 2010 to 2014 National Inpatient Sample databases to identify hospitalizations with a primary diagnosis of ALI. Patients were propensity-score matched on the likelihood of undergoing endovascular versus surgical revascularization using a logistic regression model. The primary outcome was in-hospital mortality. Secondary outcomes included myocardial infarction, stroke, composite of death/myocardial infarction/stroke, any amputation, fasciotomy, acute kidney injury, major bleeding, transfusion, vascular complications, length of stay, and hospital costs.

RESULTS

Of 10 484 (weighted national estimate=51 914) hospitalizations for ALI, endovascular revascularization was performed in 5008 (47.8%) and surgical revascularization in 5476 (52.2%). In the propensity-score matched cohort (n=7746; 3873 per group), patients who underwent endovascular revascularization had significantly lower in-hospital mortality (2.8% versus 4.0%; P=0.002), myocardial infarction (1.9% versus 2.7%; P=0.022), composite of death/myocardial infarction/stroke (5.2% versus 7.5%; P<0.001), acute kidney injury (10.5% versus 11.9%; P=0.043), fasciotomy (1.9% versus 8.9%; P<0.001), major bleeding (16.7% versus 21.0%; P<0.001), and transfusion (10.3% versus 18.5%; P<0.001), but higher vascular complications (1.4% versus 0.7%; P=0.002), compared with those undergoing surgical revascularization. Rates of any amputation were similar between the 2 groups (4.7% versus 5.1%; P=0.43). Median length of stay was shorter and hospital costs higher with endovascular versus surgical revascularization.

CONCLUSIONS

In patients with ALI, endovascular revascularization was associated with better in-hospital clinical outcomes compared with surgical revascularization. Contemporary randomized controlled trials are needed to determine the optimal revascularization strategy for ALI.

Effect of Intra-operative Intra-arterial Thrombolysis on Long Term Clinical Outcomes in Patients with Acute Popliteal Artery Aneurysm Thrombosis

OBJECTIVE

Acute lower limb ischaemia (ALI) as a result of popliteal artery aneurysm (PAA) thrombosis represents a significant problem. The aim of this study was to investigate outcome of intra-operative intra-arterial thrombolysis in the treatment of acute ischaemia due to PAA thrombosis in terms of major adverse limb events (MALE), overall survival, and intrahospital complications, especially those associated with bleeding.

METHODS

A total of 156 patients with Rutherford grade IIa and IIb acute ischaemia resulting from PAA thrombosis were admitted between 1 January 2011 and 1 January 2017. The patients were divided into two groups, those who underwent additional treatment with intra-operative intra-arterial thrombolysis (20 patients), and those who did not (136 patients). By using covariables from baseline and angiographic characteristics, a propensity score was calculated for each patient. Each patient who underwent intra-operative thrombolysis was matched to four patients from the non-thrombolysis group. Thus, comparable patient cohorts (20 in the thrombolysis and 80 in the non-thrombolysis group) were identified for further analysis. The primary end point was MALE and the secondary endpoint all cause mortality.

RESULTS

After a median follow up of 55 months, the estimated MALE rate was significantly lower in the thrombolysis group (30% vs. 65%, chi square = 10.86, p < .001, log rank test). Also, patients in the thrombolysis group had a significantly lower mortality rate (20% vs. 42.65%, chi square = 3.65, p = .05, log rank test). The thrombolysis group had wound/haematoma related interventions performed more commonly (25% in thrombolysis vs 8%, in non-thrombolysis group), but the difference was not significant (p=.013). There were no cases of major (intracranial and gastrointestinal) bleeding in either group.

CONCLUSION

The data suggest that intra-operative thrombolysis in the treatment of selected patients with ALI due to PAA thrombosis has long term MALE and overall survival benefits, without a significant risk of major, life threatening bleeding complications.

Risk factors and safe contrast volume thresholds for postcontrast acute kidney injury after peripheral vascular interventions

OBJECTIVE

Postcontrast acute kidney injury (PC-AKI) is a dreaded complication of peripheral vascular interventions (PVIs) that depends on the volume of contrast administered as well as a patient's baseline kidney function. However, there is currently no guidance on the volume of contrast that is considered safe especially for patients with advanced chronic kidney disease (CKD). This study aims to characterize the incidence, risk factors for, and outcomes after PC-AKI and define thresholds of safety for contrast volume.

METHODS

The Vascular Quality Initiative files for PVI (2010-2018) were reviewed. Patients on dialysis, with renal transplants, or who developed a bleeding complication were excluded. Only records with complete data on baseline creatinine, contrast volume, and PC-AKI (creatinine increase of ≥0.5 mg/dL, or new dialysis requirement) were included. The cumulative incidence of PC-AKI with contrast volume at each stage of CKD was derived. A safe threshold for contrast volume was defined as the volume at which the cumulative incidence of PC-AKI is 0.5% or less. Multivariable logistic regression was used to define risk factors for PC-AKI, and survival analysis was performed using Kaplan-Meier and multivariable Cox proportional hazards regression.

RESULTS

A total of 53,780 procedures were included. There were 16,062 patients (29%) with normal kidney function or CKD1, 21,769 (39%) with CKD2, 14,234 (25%) with CKD3, 1471 (3%) with CKD4, and 199 (<1%) with CKD5. The incidence of PC-AKI was 0.9% and increased with each stage of CKD (CKD1, 0.39%; CKD2, 0.45%; CKD3, 1.5%; CKD4, 4.3%; and CKD5, 7.5%). The safe thresholds for contrast volume for advanced CKD were 50, 20, and 9 mL for CKD3, CKD4, and CKD5, respectively. Regression analysis demonstrated that white race (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.54-0.82) and elective surgery (OR, 0.77; 95% CI, 0.62-0.95) were associated with decreased risk of PC-AKI, whereas inpatient status (OR, 14.5; 95% CI, 9.97-21.2), diabetes (OR, 1.27; 95% CI, 1.02-1.58), advanced CKD (CKD3: OR, 3.65; 95% CI, 2.68-4.98; CKD4: OR, 6.98; 95% CI, 4.72-10.3; CKD5: OR, 8.94; 95% CI, 4.53-17.6), critical limb ischemia (OR, 1.51; 95% CI, 1.14-2.00), acute limb ischemia (OR, 2.47; 95% CI, 1.70-3.59), and contrast-to-eGFR ratio (CGR) (2 ≤ CGR < 3: OR, 1.33; 95% CI, 1.02-1.74; 3 ≤ CGR < 4: OR, 1.90; 95% CI, 1.32-2.75; CGR ≥ 4: OR, 1.79; 95% CI, 1.18-2.70) were significantly associated with increased risk for PC-AKI. Patients who developed PC-AKI had worse in-hospital (16.1% vs 0.45%; P < .01) mortality and long-term survival (log-rank P < .01) compared with those without PC-AKI.

CONCLUSIONS

PVI are associated with low risk of PC-AKI that significantly increases when patients with advanced CKD undergo high acuity cases. Given the strong association with short-term and long-term mortality, risk of PC-AKI should be minimized by using safe thresholds of contrast volume.

Standardisation of Technique and Volume of Iodinated Contrast Administration During Infrainguinal Angioplasty

BACKGROUND

Acute Kidney injury is recognised to occur after administration of iodinated contrast during endovascular interventions for peripheral arterial disease. There are no standardised protocols for contrast delivery during infrainguinal angiography.

OBJECTIVE

The objective of this paper is to review published practice regarding the technique of conventional infrainguinal angiography and intervention, and describe a standard set of subtraction views, injection rates and contrast volumes for infrainguinal angioplasty.

METHODS

Database searches and review of papers containing (Angioplasty or Angiography) and ("lower limb" or peripheral or infrainguinal) and (method or technique or guidelines or protocol) was performed and defined procedures assessed.

RESULTS

A small number of papers provided specific technical details relating to contrast volumes and angiography views. There was considerable variation from authors who have described the contrast volumes used for lower limb angiography. We describe our simple and consistent method. The precise pathophysiology of contrast related nephropathy is under scrutiny. There is interest in new technology to minimise contrast induced kidney injury.

CONCLUSION

Few publications specify iodinated contrast doses, injection volumes or imaging views for infrainguinal arteriography. Standard infrainguinal angioplasty can be performed with conventional equipment using relatively small volumes of contrast by following a systematic technique.

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.