Contrast induced-acute kidney injury following peripheral angiography with carbon dioxide versus iodinated contrast media: A meta-analysis and systematic review of current literature

Microvascular changes following exposure to iodinated contrast media in vitro. A qualitative comparison to serum creatinine concentrations in post-cardiac catheterization patients

INTRODUCTION

Contrast-associated acute kidney injury (CA-AKI) is characterized as a loss of renal function following radiological contrast media administration. While all contrast media induce variable changes in microvascular endothelial cells in vitro, only few studies report clinical significance of their findings. A comprehensive assessment of the effect of iodinated contrast media on the renal function in vitro and in vivo is essential. The aim of our study was to morphometrically quantify the effect of two different contrast media (Iobitridol and Iodixanol) on vascular endothelial capillaries in vitro and to analyze their effect on the renal function of patients who underwent cardiac catheterization including the intra-arterial administration of contrast media, by measuring serum creatinine concentration (SCr), a byproduct of muscle metabolism, primarily excreted by the kidneys. Our hypothesis suggests that conducting a qualitative comparison of both outcomes will enable identification of differences and similarities between in vitro and in vivo exposure.

MATERIAL AND METHODS

In vitro, co-cultures of human dermal fibroblasts and human dermal microvascular endothelial cells forming capillary beds were exposed to a mixture of phosphate buffered saline and either Iobitridol, Iodixanol, or one of their supplements EDTA or Trometamol for 1.5 or 5 min. Negative control co-cultures were exposed exclusively to phosphate buffered saline. Co-cultures were either directly fixed or underwent a regeneration time of 1, 3 or 7 days. An artificial intelligence software was trained for detection of labeled endothelial capillaries (CD31) on light microscope images and measurements of morphometric parameters. In vivo, we retrospectively analyzed data from patients who underwent intra-arterial administration of contrast media and for whom SCr values were available pre- and post-contrast exposition (1, 3, and 7 days following procedure). Temporal development of SCr and incidence of CA-AKI were assessed. Both exposure types were qualitatively compared.

RESULTS

In vitro, Iobitridol, Iodixanol and EDTA induced a strong decrease of two morphometric parameters after 3 days of regeneration. In vivo, a significant increase of SCr and incidence of CA-AKI was observed 3 days following procedure in the post-contrast media patients. No difference was observed between groups.

DISCUSSION

Two of the morphometric parameters were inversely proportional to the SCr of the patients. If the endothelial damages observed in vitro occur in vivo, it may result in renal hypoxia, inducing a loss of kidney function clinically translated into an increase of SCr. Further development of our in vitro model could allow closer replication of the internal structure of a kidney and bridge the gap between in vitro studies and their clinical findings.

Safety, Effectiveness and Pitfalls of Carbon Dioxide Routine Use as a Contrast Agent for Endovascular Abdominal Aortic Repair

BACKGROUND

Despite the evidence of good performance, carbon dioxide (CO2) routine employment as a contrast agent for endovascular procedures is far from being adopted with its use currently limited to patients with renal impairment and known allergy to iodinated contrast medium (ICM). The purpose of our study is to evaluate the safety and effectiveness of CO2 guided endovascular abdominal aortic aneurysm repair (EVAR) in a standard population and to assess the rationale for a future widespread use.

METHODS

We retrospectively collected data of every patient who underwent CO2 guided standard EVAR from September 2020 to May 2021 and compared them with the data of every patient who underwent EVAR using ICM from December 2019 to August 2020 in our unit. The selection of the contrast medium was not based on any preoperative factor as the contrast medium was routinely used in every patient in both periods. The primary end point of the study was the technical success rate. Secondary end points were the early and late complication rates, radiation exposure and renal function impairment.

RESULTS

49 patients underwent ICM guided EVAR and 52 patients underwent CO2 guided EVAR in our unit in the time frames specified above. The technical success rate was 100% in both groups with no accidental coverage of any target vessel. Intraoperative endoleaks were observed in 14% of ICM patients and 25% of CO2 patients. The radiation exposure was higher in the CO2 group if compared to the ICM group (311.48 vs. 159.86 median mGy/cm2 - P < 0.001). The incidence of postoperative acute kidney injury was low and similar in the 2 groups. No significant worsening over time of the renal function has been reported in both groups.

CONCLUSIONS

EVAR can be safely performed under CO2 guidance without the integration of any quantity of ICM but with an increase in radiation exposure. The nephroprotective role of CO2 guided EVAR in a standard population is unclear and the same role in renal impaired patients should be validated with further studies on selected populations.

The intellectual base and global trends in contrast-induced acute kidney injury: a bibliometric analysis

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired kidney injury. A comprehensive analysis of the current state of research in the field of CI-AKI will help to reveal trends and hot topics in the field. To date, there are no published bibliometric analyses related to CI-AKI studies. Here, we analyze the relevant literature since the emergence of the concept and provide valuable insights. The literature was collected from the Web of Science Core Collection. The data were analyzed visually using CiteSpace and VOSviewer software. We collected a total of 4775 papers, with the United States and Guangdong Acad Med Sci as the major publishing powers in terms of country/region and institution. J AM COLL CARDIOL was the journal with the most published and cocited articles. Cluster analysis showed that clinical trials are the current research hotspot. The areas of risk assessment, prevention strategies, risk factors, and vascular lesions have been popular in recent years. Research on the mechanism of injury in CI-AKI will be the focus of future research, which will be crucial to reduce the clinical incidence of CI-AKI. In summary, this study provides a comprehensive analysis of the development process in the field of CI-AKI and discusses future research directions based on the analysis of objective data from many studies on CI-AKI.

Outcomes of lower extremity peripheral arterial interventions in patients with and without chronic kidney disease or end-stage renal disease

INTRODUCTION

Peripheral arterial disease (PAD) is a progressive vascular condition characterized by the narrowing or blockage of arteries, primarily attributed to atherosclerosis. PAD's prevalence in the general population is estimated at approximately 5.9%. Notably however, among patients with chronic kidney disease (CKD), PAD's prevalence is substantially higher, ranging from 17% to 48%. This review paper emphasizes the pervasiveness of PAD and its intricate relationship with CKD and end-stage renal disease (ESRD). It demonstrates the importance of early detection, proactive screening, and understanding the formidable challenges associated with treating heavily calcified lesions.

EVIDENCE ACQUISITION

Comprehensive literature searches encompassed the PubMed/MEDLINE, Cochrane Library, and Embase databases, in order to identify studies involving lower extremity peripheral arterial interventions in patients both with and without CKD or ESRD. The search spanned the timeframe from January 2001 to July 2023. The search strategy included vocabulary terms concerning peripheral artery disease, lower extremities, revascularization, chronic kidney disease, and end-stage renal disease.

EVIDENCE SYNTHESIS

Initial searches were used to identify articles based on title. Exclusion criteria was then applied, and any redundant articles were removed. The articles abstracts were then reviewed, and relevant articles were selected. Once selected the articles were thoroughly reviewed including the references to find other relevant articles that were missed during the initial search process. In total 28 articles were selected and included for review of clinical data in regard to PAD outcomes in patients with advanced kidney disease.

CONCLUSIONS

The findings highlight the need for personalized approaches in diagnosing and treating PAD in CKD and ESRD patients. Interdisciplinary collaboration, such as those between nephrologists, vascular surgeons, and interventional radiologists, is vital to optimize outcomes. Further research should focus on innovative, tailored interventions to enhance limb preservation, reduce mortality, prolong patency, and cut healthcare costs.

Risk of Acute Kidney Injury Following IV Iodinated Contrast Media Exposure: 2023 Update, From the AJR Special Series on Contrast Media

Iodinated contrast material (ICM) has revolutionized the field of diagnostic radiology through improvements in diagnostic performance and expansion in clinical indications for radiographic and CT examinations. Historically, nephrotoxicity was a feared complication of ICM use, thought to be associated with a significant risk of morbidity and mortality. Such fears often precluded use of ICM in imaging evaluations, commonly at the expense of diagnostic performance and timely diagnosis. Over the past 20 years, the nephrotoxic risk of ICM has become a topic of debate, as more recent evidence from higher-quality studies now suggest that many cases of what was considered contrast-induced acute kidney injury (CI-AKI) were likely cases of mistaken causal attribution; most of these cases represented either acute kidney injury (AKI) caused by any of myriad other known factors that can adversely affect renal function and were coincidentally present at the time of contrast media exposure (contrast-associated AKI (CA-AKI)) or a manifestation of the normal variation in renal function that increases with worsening renal function. This review discusses the current state of knowledge on CI-AKI and CA-AKI including the incidence, risk factors, outcomes, and prophylactic strategies in the identification and management of these clinical conditions.

Implications of Kidney Disease in Patients with Peripheral Arterial Disease and Vascular Calcification

Persons with chronic kidney disease (CKD) are at a higher risk of developing peripheral artery disease (PAD) and its adverse health outcomes than individuals with normal renal function. Among patients with CKD, PAD is predominantly characterized by the calcification of the medial layer of arterial vessels in addition to intimal atherosclerosis and calcification. Vascular calcification (VC) is initiated by CKD-associated hyperphosphatemia, hypercalcemia, high concentrations of parathyroid hormone (PTH) as well as inflammation and oxidative stress. VC is widely prevalent in this cohort (>80% dialysis and 50% patients with CKD) and contributes to reduced arterial compliance and symptomatic peripheral arterial disease (PAD). The most severe form of PAD is critical limb ischemia (CLI) which has a substantial risk for increased morbidity and mortality. Percutaneous endovascular interventions with transluminal angioplasty, atherectomy, and intravascular lithotripsy are the current nonsurgical treatments for severe calcific plaque. Unfortunately, there are no randomized controlled trials that address the optimal approach to PAD and CLI revascularization in patients with CKD.

Total iodine contrast-free strategy for the endovascular management of abdominal aortic aneurysms in chronic kidney disease patients: a pilot study

OBJECTIVES

To retrospectively evaluate the feasibility and effectiveness of the endovascular treatment of patients with abdominal aortic aneurysm (AAA) and chronic kidney disease (CKD) without the need for using iodinated contrast media (ICM) throughout the diagnostic, therapeutic and follow-up pathway.

METHODS

A retrospective review of prospectively collected data concerning 251 consecutive patients presenting an abdominal aortic or aorto-iliac aneurysm who underwent endovascular aneurysm repair (EVAR) from January 2019 to November 2022 at our academic institution was performed in order to identify patients with feasible anatomy with respect to manufacturers' instructions for use (IFU) and with CKD. Patients whose preoperative workout included duplex ultrasound (DUS) and plain computed tomography (pCT) for pre-procedural planning were extracted from a dedicated EVAR database. EVAR was performed with the use of carbon dioxide (CO₂) as contrast media of choice, whereas follow-up examinations consisted of either DUS, pCT or contrast-enhanced ultrasound (CEUS). Primary endpoints were technical success, perioperative mortality and early renal function variations. Secondary endpoints were all-type endoleaks (EL) and reinterventions, mid-term aneurysm-related and kidney-related mortality.

RESULTS

Forty-five patients had CKD and were treated electively (45/251, 17.9%). Of them, seventeen patients were managed with a total ICM-free strategy and constituted the object of the present study (17/45, 37.8%; 17/251, 6.8%). In seven cases an adjunctive planned procedure was performed (7/17, 41.2%). No intraoperative bail-out procedures were needed. This extracted cohort of patients presented similar mean preoperative and postoperative (at discharge) GFRs values, 28.14 (SD 13.09; median 28.06, IQR 20.25) ml/min/1.73m² and 29.33 (SD 14.61; median 27.35, IQR 22) ml/min/1.73m² respectively (p= .210). Mean follow-up was 16.4 months (SD 11.89; median 18, IQR 23). During follow-up no graft-related complications occurred in terms of either thrombosis, type I or III EL, aneurysm rupture or conversion. The mean GFR at follow-up was 30.39 ml/min/1.73m² (SD 14.45; median 30.75, IQR 21.93), with no significant worsening in comparison with pre and postoperative values (p= .327 and p= .856 respectively). No aneurysm- or kidney-related deaths occurred during follow-up.

CONCLUSIONS

Our initial experience shows that total iodine contrast-free AAA endovascular management in patients with CKD may be feasible and safe. Such an approach seems to guarantee the preservation of residual kidney function without increasing the risks of aneurysm-related complication in the early and midterm postoperative period and it could be considered even in case of complex endovascular procedures.

Contrast-Associated Acute Kidney Injury in High-Risk Patients Undergoing Peripheral Vascular Interventions

Objective: This study aims to evaluate the use of prophylactic intravenous hydration (IV prophylaxis) and carbon dioxide (CO₂) angiography in reducing contrast associated-acute kidney injury (CA-AKI) and determine the overall incidence and risk factors of CA-AKI in high-risk patients undergoing peripheral vascular interventions (PVI). Method: Only patients undergoing elective PVI from 2017 to 2021 with chronic kidney disease (CKD) stage 3-5 in the Vascular Quality Initiative (VQI) database were included. Patients were grouped into IV prophylaxis vs no prophylaxis. The study's primary outcome was CA-AKI, defined as a rise in creatinine (>.5 mg/dL) or new dialysis within 48 hours following contrast administration. Standard univariate and multivariable (logistic regression) analyses were conducted. Results: A total of 4497 patients were identified. Of these, 65% received IV prophylaxis. The overall incidence of CA-AKI was .93%. No significant difference was seen in overall contrast volume (mean (SD): 66.89(49.54) vs 65.94(51.97) milliliters, P > .05) between the 2 groups. After adjusting for significant covariates, the use of IV prophylaxis (OR (95% CI): 1.54(.77-3.18), P = .25) and CO₂ angiography (OR (95%CI): .95(.44-2.08), P = .90) was not associated with a significant reduction in CA-AKI compared to the patients with no prophylaxis. The severity of CKD and diabetes were the only predictor of CA-AKI. Compared to patients with no CA-AKI, patients with CA-AKI were at risk of higher 30-day mortality (OR (95% CI): 11.09 (4.25-28.93)) and cardiopulmonary complications (OR (95% CI): 19.03 (8.74-41.39) following PVI (Both P < .001). Conclusion: Using a large national vascular database, our study demonstrates that prophylactic use of IV hydration and CO₂ angiography in high-risk CKD patients is not associated with a reduction in renal injury following PVI. Reduced kidney function and history of diabetes is an independent predictor of CA-AKI and patients that develop post-procedural AKI are at an increased risk of morbidity and mortality.

Risk of Contrast-Associated Acute Kidney Injury in Patients Undergoing Peripheral Angiography with Carbon Dioxide Compared to Iodine-Containing Contrast Agents: A Systematic Review and Meta-Analysis

The aim of this systematic review was to summarise the comparative evidence on the risk of contrast-associated acute kidney injury (CA-AKI) with CO₂ or iodinated contrast medium (ICM) for peripheral vascular interventions. We searched Ovid MEDLINE, Cochrane Library, Embase, Epistemonikos, PubMed-similar-articles, clinical trial registries, journal websites, and reference lists up to February 2022. We included studies comparing the risk of CA-AKI in patients who received CO₂ or ICM for peripheral angiography with or without endovascular intervention. Two reviewers screened the references and assessed the risk of bias of the included studies. We extracted data on study population, interventions and outcomes. For the risk of CA-AKI as our primary outcome of interest, we calculated risk ratios (RRs) with a 95% confidence interval (CI) and performed random-effects meta-analyses. We identified three RCTs and five cohort studies that fully met our eligibility criteria. Based on a random-effects meta-analysis, the risk of CA-AKI was lower with CO₂ compared to ICM (8.6% vs. 15.2%; RR, 0.59; 95% CI 0.33-1.04). Only limited results from a few studies were available on procedure and fluoroscopy time, radiation dose and CO₂-related adverse events. The evidence suggests that the use of CO₂ for peripheral vascular interventions reduces the risk of CA-AKI compared to ICM. However, due to the relevant residual risk of CA-AKI with the use of CO₂, other AKI risk factors must be considered in patients undergoing peripheral vascular interventions.

Contrast-Induced Acute Kidney Injury: Evidence in Support of Its Existence and a Review of Its Pathogenesis and Management

The role of contrast-induced nephropathy (CIN) remains controversial. Many experts contend that CIN does not exist or is extremely rare. The diagnosis was previously made too frequently and inappropriately in the presence of coexisting and confounding comorbidities and risk factors making it difficult to singularly isolate the etiologic role of intravenous contrast media in acute kidney injury (AKI). It is probable that many patients were denied important diagnostic information from radiocontrast studies for fear of CIN. Recently, a new terminology for CIN was introduced, and the term CIN was replaced by two interrelated new terms: one is contrast-associated acute kidney injury (CA-AKI), and the second one is contrast-induced acute kidney injury (CI-AKI). CA-AKI occurs in association with risk factors or comorbidities, therefore, it is a correlative diagnosis. On the other hand, CI-AKI is a subtype of CA-AKI that results directly from iodinated contrast media. In this review, we present evidence from various studies that argue against CI-AKI and also those that suggest its existence but with much lower frequency. We will also provide the current status of the pathophysiology and management of CA-AKI/CI-AKI.

Quiescent-Interval Single-Shot Magnetic Resonance Angiography May Outperform Carbon-Dioxide Digital Subtraction Angiography in Chronic Lower Extremity Peripheral Arterial Disease

Nephroprotective imaging in peripheral arterial disease (PAD) is often crucial. We compared the diagnostic performance of non-contrast Quiescent-interval single-shot magnetic resonance angiography (QISS MRA) and carbon-dioxide digital subtraction angiography (CO2 DSA) in chronic lower extremity PAD patients. A 19-segment lower extremity arterial model was used to assess the degree of stenosis (none, <50%, 50−70%, >70%) and the image quality (5-point Likert scale: 1-non-diagnostic, 5-excellent image quality). Intra-class correlation coefficient (ICC) was calculated for inter-rater reliability. Diagnostic accuracy and interpretability were evaluated using CO2 DSA as a reference standard. 523 segments were evaluated in 28 patients (11 male, mean age: 71 ± 9 years). Median and interquartile range of subjective image quality parameters for QISS MRA were significantly better compared to CO2 DSA for all regions: (aortoiliac: 4 [4−5] vs. 3 [3−4]; femoropopliteal: 4 [4−5] vs. 4 [3−4]; tibioperoneal: 4 [3−5] vs. 3 [2−3]; all regions: 4 [4−5] vs. 3 [3−4], all p < 0.001). QISS MRA out-performed CO2 DSA regarding interpretability (98.3% vs. 86.0%, p < 0.001). Diagnostic accuracy parameters of QISS MRA for the detection of obstructive luminal stenosis (70%<) as compared to CO2 DSA were as follows: sensitivity 82.6%, specificity 96.9%, positive predictive value 89.1%, negative predictive value 94.8%. Regarding the degree of stenosis, interobserver variability for all regions was 0.97 for QISS MRA and 0.82 for CO2 DSA. QISS MRA proved to be superior to CO2 DSA regarding subjective image quality and interpretability for the imaging of chronic lower extremity PAD.

The Role of RIPC in Preventing Organ Damage, Inflammation, and Oxidative Stress during Lower Limb DSA: A Randomised Controlled Trial

Objective

Diagnostic digital subtraction angiography (DSA) and DSA with percutaneous transluminal angioplasty (DSA-PTA) are common procedures for diagnosing and treating symptomatic lower extremity arterial disease (LEAD). However, organ damage following DSA and DSA-PTA is often underrecognised and hence undiagnosed. To reduce the risk induced by invasive procedures in symptomatic LEAD patients, the method of remote ischemic preconditioning (RIPC) has been suggested. The aim of the current study was to assess the effect of RIPC intervention on the organ damage markers profile, oxidative stress, and inflammation biomarkers in LEAD patients undergoing DSA and DSA-PTA procedure.

Methods

The RIPC intervention was performed by inflating a standard blood pressure cuff on the patient's upper arm to 200 mmHg for 5 minutes four times with 5-minute perfusion between each cycle. The sham intervention was performed similarly, but the cuff was inflated to 20 mmHg. Changes in the cardiac and renal damage biomarkers' profile, oxidative stress, and inflammation biomarkers were recorded before and 24 hours after DSA or DSA-PTA.

Results

A total of 111 (RIPC 54, sham 57) patients with symptomatic LEAD scheduled for endovascular procedure were randomised, and 102 patients (RIPC 47, sham 55) completed the study protocol. RIPC significantly limited the increase of adiponectine levels after DSA and DSA-PTA, compared to sham intervention (p = 0.020), but CK-MB levels were markedly lower in the sham group (p = 0.047) after procedure. There was no significant difference between the RIPC and the sham group in mean changes in hs-troponin-T (p = 0.25), NT-proBNP (p = 0.24), creatinine (p = 0.76), eGFR (p = 0.61), urea (p = 0.95), beta-2-microglobuline (p = 0.34), or cystatine C (p = 0.24) levels.

Conclusion

In this controlled clinical study, RIPC failed to improve the profile of renal and cardiac biomarkers in patients with LEAD periprocedurally. RIPC significantly limits the rise in adiponectin levels and may influence the decrease of CK-MB levels 24 hours after endovascular procedure.

CO2-based C-arm computed tomography (CACT) of the pelvic arteries: feasibility and diagnostic performance in comparison to CO2-angiography in patients with peripheral arterial disease

BACKGROUND

Patients with substantially impaired kidney function and peripheral arterial disease (PAD) underwent comparative CO₂-based depiction of the pelvic arteries (PAs).

PURPOSE

To evaluate the feasibility and diagnostic performance of CO₂-based C-arm computed tomography (CACT) and compare its depiction of PAs with CO₂-digital subtraction angiography (DSA).

MATERIAL AND METHODS

Fifteen patients (10 men, mean age 70 ± 11 years) with PAD received CO₂-DSA and CO₂-CACT of the PAs, depicted from the aorta to femoral arteries. These were divided into nine segments (135 in total) and graded by two independent readers for image quality (IQ; 1 = sufficient, 2 = minimal impairments, 3 = insufficient, 4 = outside field of view) and subsequent stenosis grading (SG; grade 1: normal to grade 4: occlusion), under exclusion of all segments with insufficient IQ. Inter-observer and inter-modality agreement calculation and subsequent consensus reading were performed and correlated to a standard of reference (StOR), representing a modality consensus.

RESULTS

Of 135 segments, 117 showed sufficient IQ, excluding 18 segments (10 CACT, 8 DSA). Inter-observer agreement for IQ and consecutive SG demonstrated good to excellent agreement: IQ_DSA: κ = 0.83, IQ_CACT: κ = 0.76; Stenosis_DSA: κ = 0.71, Stenosis_CACT: κ = 0.84. Inter-modality agreement for SG lay at κ = 0.76 and κ = 0.65, respectively. More stenoses could be detected by CACT, and analysis of pooled consensus values of SG in CACT_cons versus StOR showed an excellent agreement (κ = 0.96) that proved considerably higher than the moderate agreement between consensus values in DSA_cons versus StOR (κ = 0.43).

CONCLUSION

CO₂-CACT proved feasible, and has the potential to optimize angiographic work-up of PAD in patients with contraindications for other contrast media.

Acute Kidney Injury Following In-Patient Lower Extremity Vascular Intervention: From the National Cardiovascular Data Registry

OBJECTIVES

The authors analyzed data from the NCDR (National Cardiovascular Data Registry) PVI Registry and defined acute kidney injury (AKI) as increased creatinine of ≥0.3 mg/dl or 50%, or a new requirement for dialysis after PVI.

BACKGROUND

AKI is an important and potentially modifiable complication of peripheral vascular intervention (PVI). The incidence, predictors, and outcomes of AKI after PVI are incompletely characterized.

METHODS

A hierarchical logistic regression risk model using pre-procedural characteristics associated with AKI was developed, followed by bootstrap validation. The model was validated with data submitted after model creation. An integer scoring system was developed to predict AKI after PVI.

RESULTS

Among 10,006 procedures, the average age of patients was 69 years, 58% were male, and 52% had diabetes. AKI occurred in 737 (7.4%) and was associated with increased in-hospital mortality (7.1% vs. 0.7%). Reduced glomerular filtration rate, hypertension, diabetes, prior heart failure, critical or acute limb ischemia, and pre-procedural hemoglobin were independently associated with AKI. The model to predict AKI showed good discrimination (optimism corrected c-statistic = 0.68) and calibration (corrected slope = 0.97, intercept of -0.07). The integer point system could be incorporated into a useful clinical tool because it discriminates risk for AKI with scores ≤4 and ≥12 corresponding to the lower and upper 20% of risk, respectively.

CONCLUSIONS

AKI is not rare after PVI and is associated with in-hospital mortality. The NCDR PVI AKI risk model, including the integer scoring system, may prospectively estimate AKI risk and aid in deployment of strategies designed to reduce risk of AKI after PVI.

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.

Safety and outcomes of combined carbon dioxide angiography and OCT-guided femoro-popliteal chronic total occlusion crossing and directional atherectomy in patients with chronic kidney disease

BACKGROUND

Carbon dioxide angiography with addition of optical coherence tomography imaging may improve procedural success and clinical outcomes in patients with peripheral artery disease and chronic kidney disease.

METHODS

Single-center, retrospective analysis of patients with chronic kidney disease who underwent carbon dioxide angiography and optical coherence tomography-guided chronic total occlusion crossing and/or optical coherence tomography-guided directional atherectomy was performed. Patient and procedure-related characteristics, along with peri- and one-year post-procedural major adverse events, were analyzed.

RESULTS

A total of 18 vessels in 11 patients, with mean age 70 years were treated. All had co-morbidities such as hypertension, hyperlipidemia, had history or were current smokers with baseline peripheral artery disease. Majority were diabetic with coronary disease (82%); 55% baseline chronic kidney disease IV, 55% Rutherford class III and 45% class IV. Contrast was used in only two patients. Mean total fluoroscopy time and radiation dose was 24.1 min and 249.2 mGY, respectively. Half of the lesions were femoro-popliteal chronic total occlusions, and Ocelot catheter was used to cross seven of nine chronic total occlusions and was successful in six. Adjunctive optical coherence tomography-guided directional atherectomy was performed in 8 of 11 patients. Only two adverse events occurred: one clinically significant event of slow-flow intra-procedurally and one target limb revascularization within one year of index procedure in a vessel different than prior treated. Optical coherence tomography imaging in both chronic total occlusion-crossing and atherectomy resulted in 10-min mean fluoroscopy reduction time and 32 mGY reduction in radiation dose.

CONCLUSION

Carbon dioxide angiography with the addition of optical coherence tomography imaging for chronic total occlusion crossing and/or optical coherence tomography-guided directional atherectomy reduced the need for contrast agents, total fluoroscopy time, and radiation exposure in patients with peripheral artery disease and baseline chronic kidney disease.

Feasibility and impact of carbon dioxide angiography on acute kidney injury following endovascular interventions in patients with peripheral artery disease and renal impairment

BACKGROUND

Post-contrast acute kidney injury (AKI) is a dreaded complication of endovascular revascularization using iodinated contrast medium in patients with peripheral artery disease and concomitant chronic kidney disease (CKD). This study sought to evaluate the incidence of AKI in patients with peripheral artery disease and CKD undergoing endovascular revascularization and using carbon dioxide (CO₂) as contrast medium.

METHODS AND RESULTS

From 04/2015 to 07/2018, all consecutive peripheral artery disease patients with CKD stage ≥ 3 referred for endovascular revascularization of symptomatic peripheral artery disease were prospectively included. During endovascular revascularization, CO₂ as contrast medium was manually injected and iodinated contrast medium was additionally used when needed. The reference group consisted of 211 cardiovascular risk factor-matched patients undergoing endovascular revascularization with iodinated contrast medium only. CO₂-guided endovascular revascularization was performed in 102 patients, thereof 16 (15.7%) patients exclusively with CO₂. Baseline CKD stage ≥ 4 and iodinated contrast medium volume > 50 ml were disproportionally associated with post-procedural post-contrast AKI. At CKD stage 4 the odds ratio for post-contrast AKI was 13.2 (95% CI 1.489-117.004; p = 0.02) for iodinated contrast medium volume 51-100 ml and 37.7 (95% CI 3.927-362.234; p = 0.002) for iodinated contrast medium volume > 100 ml. The corresponding values at CKD stage 5 were 23.7 (95% CI 2.666-210.583; p = 0.005) and 28.3 (95% CI 3.289-243.252; p = 0.002), respectively. Radiation (dose area product) was significantly higher in the CO₂-endovascular revascularization group (6.025 ± 6.926 cGy*cm² vs. 4.281 ± 4.722 cGy*cm², p = 0.009).

CONCLUSION

CO₂ is an applicable and safe alternative to iodinated contrast medium for endovascular revascularization in peripheral artery disease patients with concomitant CKD. Patients with CKD stage 4 or 5, being at highest risk for post-contrast AKI, should primarily be treated by CO₂-guided endovascular revascularization.

Initial Operating Room Experience with Digital Variance Angiography in Carbon Dioxide-Assisted Lower Limb Interventions: A Pilot Study

PURPOSE

In retrospective clinical studies digital variance angiography (DVA) provided higher contrast-to-noise ratio and better image quality than digital subtraction angiography (DSA). Our aim was to verify the clinical usefulness and benefits of DVA in carbon dioxide (CO₂)-assisted lower limb interventions.

MATERIALS AND METHODS

A workstation running the DVA software was integrated into a Siemens Artis Zee with Pure angiography system, and this new image processing technology was used in four patients (3 male, 1 female, age: 76.2 ± 4.2 years) with peripheral artery disease (PAD, Rutherford 2-3) and impaired renal function (average eGFR 25.5 ± 11.2 ml/min/1.73 m²). The DSA and DVA images of 46 CO₂-assisted runs were visually evaluated by five experts in single-image evaluation using a 5-grade Likert scale and in paired comparisons.

RESULTS

DVA images received significantly higher score (3.84 ± 0.10) than DSA images (3.31 ± 0.10, p < 0.001). Raters preferred DVA images in terms of diagnostic value and usefulness for therapeutic decisions in 85.2% and 83.9% of all comparisons, respectively. These benefits were achieved at lower frame rates (1-3 FPS) than usually recommended for CO₂ angiography (4-6 FPS). No adverse events were recorded during or after the procedures.

CONCLUSIONS

Our initial experience shows that DVA might facilitate the correct diagnostic and therapeutic decisions, and potentially help to reduce radiation exposure in lower limb CO₂ angiography. Although the dose management capabilities of DVA have to be validated in further clinical studies, this technology might be a useful new tool in the operating room and contributes to the safety and efficacy of CO₂-enhanced endovascular interventions.

LEVEL OF EVIDENCE

Level IV.

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.

Acute Renal Failure/Acute Kidney Injury (AKI) Associated with Endovascular Procedures

AKI is one of the most common yet underdiagnosed postoperative complications that can occur after any type of surgery. Contrast-induced nephropathy (CIN) is still poorly defined and due to a wide range of confounding individual variables, its risk is difficult to determine. CIN mainly affects patients with underlying chronic kidney disease, diabetes, sepsis, heart failure, acute coronary syndrome and cardiogenic shock. Further research is necessary to better understand pathophysiology of contrast-induced AKI and consequent implementation of effective prevention and therapeutic strategies. Although many therapies have been tested to avoid CIN, the only potent preventative strategy involves aggressive fluid administration and reduction of contrast volume. Regardless of surgical technique—open or endovascular—perioperative AKI is associated with significant morbidity, mortality and cost. Endovascular procedures always require administration of a contrast media, which may cause acute tubular necrosis or renal vascular embolization leading to renal ischemia and as a consequence, contribute to increased number of post-operative AKIs.

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.

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.

Intra-arterial catheter-directed CT angiography for assessment of endovascular aortic aneurysm repair

OBJECTIVE

To compare the efficacy and safety as well as associated image quality of catheter-directed CT angiography (CCTA) with a low dose of iodine contrast agent compared to intravenous CTA in patients undergoing endovascular aortic aneurysm repair (EVAR).

METHODS

Retrospective data analysis of 92 patients undergoing EVAR between January 2009 and December 2017 was performed. Patients were divided in two groups; those receiving CTA (n = 59) after intravenous contrast agent application and those receiving CCTA (n = 33) via an intraarterial catheter placed in the descending aorta. Demographic and cardiovascular risk factors as well as renal function parameters before, immediately after and 6-60 months after EVAR were evaluated. As primary endpoint, changes in serum creatinine levels in the two groups were evaluated. Secondary endpoints encompassed complications associated with intraarterial catheter placement. Objective (signal-to-noise ratios) and subjective image quality (5-point Likert scale) were compared.

RESULTS

Amount of contrast medium was significantly lower in CCTA compared to i.v. CTA (23 ± 7 ml vs. 119 ± 15 ml, p<0.0001). Patients undergoing catheter-directed CTA had higher baseline creatinine values compared to the group with intravenous iodine application (1.9 ± 0.6 mg/dl vs. 1.3 ± 0.5 mg/dl; p<0.0001). Follow-up serum creatinine levels however did not show significant alterations between the two groups (1.9 ± 0.4 mg/dl vs. 1.3 ± 0.5 mg/dl). No major complications were detected in the CCTA group. Signal-to-noise ratio (SNR) was comparable between i.v. CTA and CCTA (8.5 ± 4.6 vs. 7.7 ± 4.0; p = 0.37) and subjective image similarly revealed no differences with a good interobserver agreement (ICC = 0.647).

CONCLUSIONS

Catheter-directed CTA is safe and provides comparable image quality with a substantial retrenchment of the needed amount of iodine-based contrast medium. However, no benefit of the reduced contrast medium protocol with respect to renal function was observed.

Renal denervation using carbon dioxide renal angiography in patients with uncontrolled hypertension and moderate to severe chronic kidney disease

Background

Chronic kidney disease (CKD) is the most common cause of secondary hypertension. More than half of the patients have uncontrolled hypertension (≥140/90 mmHg on three or more antihypertensive agents at optimum doses). Renal sympathetic denervation (RSDN) has been shown to reduce blood pressure (BP) in patients with resistant hypertension. Although patients with CKD have high sympathetic drive, all major clinical trials have excluded patients with estimated glomerular filtration rates (eGFRs) <45 mL/min/1.73m² for risk of contrast-induced nephropathy.

Methods

In this pilot study, carbon dioxide (CO₂) was used as the sole contrast agent to carry out renal angiography and RSDN in patients with moderate to severe CKD (eGFR 15–44 mL/min/1.73m²) and uncontrolled hypertension.

Results

Eleven patients (eight males) underwent RSDN. The median age was 57 years [interquartile range (IQR) 49–66]. The median number of antihypertensives being taken at baseline was 4 (IQR 3–4). No statistically significant difference was observed in serum creatinine in the serial follow-ups until at 6 months[median difference 0.25 mg/dL (IQR 0.09–0.53); P = 0.008]. There was a non-significant reduction in median clinic BP from baseline to 6 months [−14 mmHg (IQR −24–5)] and a significant increase in daytime ambulatory systolic BP [7 mmHg (IQR −2–12); P= 0.045]. A trend towards a serial reduction in albuminuria was observed. Procedure-related complications included a groin haematoma (n = 1) and reported flank (n = 1) and groin pain (n = 1).

Conclusions

This pilot study shows that CO₂ renal angiography can be used to perform RSDN in patients with significant renal impairment and may lead to associated improvements in clinic BP and albuminuria.