Neurons Over Nephrons: Systematic Review and Meta-Analysis of Contrast-Induced Nephropathy in Patients With Acute Stroke

ABCD2-I Score Predicts Unplanned Emergency Department Revisits within 72 Hours Due to Recurrent Acute Ischemic Stroke

BACKGROUND

the ABCD2 score is valuable for predicting early stroke recurrence after a transient ischemic attack (TIA), and Doppler ultrasound can aid in expediting stroke triage. The study aimed to investigate whether combining the ABCD2 score with carotid duplex results can enhance the identification of early acute ischemic stroke after TIA.

METHODS

we employed a retrospective cohort design for this study, enrolling patients diagnosed with TIA who were discharged from the emergency department (ED). The modified ABCD2-I (c50) score, which incorporates a Doppler ultrasound assessment of internal carotid artery stenosis > 50%, was used to evaluate the risk of acute ischemic stroke within 72 h. Patients were categorized into three risk groups: low risk (with ABCD2 and ABCD2-I scores = 0-4), moderate risk (ABCD2 score = 4-5 and ABCD2-I score = 5-7), and high risk (ABCD2 score = 6-7 and ABCD2-I score = 8-9).

RESULTS

between 1 January 2014, and 31 December 2019, 1124 patients with new neurological deficits were screened, with 151 TIA patients discharged from the ED and included in the analysis. Cox proportional hazards analysis showed that patients in the high-risk group, as per the ABCD2-I (c50) score, were significantly associated with revisiting the ED within 72 h due to acute ischemic stroke (HR: 3.12, 95% CI: 1.31-7.41, p = 0.0102), while the ABCD2 alone did not show significant association (HR: 1.12, 95% CI: 0.57-2.22, p = 0.7427).

CONCLUSION

ABCD2-I (c50) scores effectively predict early acute ischemic stroke presentations to the ED within 72 h after TIA.

Incidence of acute kidney injury in patients with acute ischaemic stroke undergoing CT angiography (CTA) and CT perfusion (CTP): a systematic review and meta-analysis

Background and purpose

We conducted a systematic review and meta-analysis to assess the incidence of acute kidney injury (AKI) in patients undergoing CT angiography (CTA) and CT perfusion (CTP) for acute ischaemic stroke (AIS). Concerns over contrast-induced nephropathy (CIN) often lead medical centres to mandate pre-imaging serum creatinine level assessments, causing unnecessary delays. We aim to confirm further the practice of conducting CTA/CTP without first testing creatinine.

Methods

We searched PubMed, Cochrane Central and Scopus from inception until March 2023 for studies reporting on AKI in patients with AIS receiving CTA/CTP. Outcomes of interest were (1) the odds of AKI in patients receiving CTA/CTP versus non-contrast CT and (2) the overall incidence of AKI and haemodialysis in patients with AIS undergoing CTA/CTP.

Results

Results were pooled using a random effects model. 13 studies were included (5 cohort and 8 single-arm studies) with 5104 patients in total, out of which 4347 patients received CTA/CTP and 757 patients received no contrast. In case-control studies, 4.8% (OR=0.66, 95% CI 0.35 to 1.22, Z=1.32, p=0.19) of patients who received CTA/CTP developed AKI, compared with 7.7% of patients in the control group. Temporary haemodialysis was required for two patients in the analysed studies.

Conclusions

Non-randomised evidence suggests that CTA/CTP is not associated with a statistically significant increase in the risk of AKI in patients with stroke. Further well-designed prospective studies are required to explore potential risk factors of CIN in specific patient populations such as diabetes mellitus and chronic kidney disease.

Value of Immediate Flat Panel Perfusion Imaging after Endovascular Therapy (AFTERMATH): A Proof of Concept Study

BACKGROUND AND PURPOSE

Potential utility of flat panel CT perfusion imaging (FPCT-PI) performed immediately after mechanical thrombectomy (MT) is unknown. We aimed to assess whether FPCT-PI obtained directly post-MT could provide additional potentially relevant information on tissue reperfusion status.

MATERIALS AND METHODS

This was a single-center analysis of all patients with consecutive acute stroke admitted between June 2019 and March 2021 who underwent MT and postinterventional FPCT-PI (n = 26). A core lab blinded to technical details and clinical data performed TICI grading on postinterventional DSA images and qualitatively assessed reperfusion on time-sensitive FPCT-PI maps. According to agreement between DSA and FPCT-PI, all patients were classified into 4 groups: hypoperfusion findings perfectly matched by location (group 1), hypoperfusion findings mismatched by location (group 2), complete reperfusion on DSA with hypoperfusion on FPCT-PI (group 3), and hypoperfusion on DSA with complete reperfusion on FPCT-PI (group 4).

RESULTS

Detection of hypoperfusion (present/absent) concurred in 21/26 patients. Of these, reperfusion findings showed perfect agreement on location and size in 16 patients (group 1), while in 5 patients there was a mismatch by location (group 2). Of the remaining 5 patients with disagreement regarding the presence or absence of hypoperfusion, 3 were classified into group 3 and 2 into group 4. FPCT-PI findings could have avoided TICI overestimation in all false-positive operator-rated TICI 3 cases (10/26).

CONCLUSIONS

FPCT-PI may provide additional clinically relevant information in a considerable proportion of patients undergoing MT. Hence, FPCT-PI may complement the evaluation of reperfusion efficacy and potentially inform decision-making in the angiography suite.

Acute kidney injury after endovascular therapy in acute stroke patients: systematic review with meta-analysis

AIMS

Endovascular therapy (EVT) is a highly effective stroke treatment, but it requires the administration of contrast media which puts patients at risk of acute kidney injury (AKI). AKI is associated with increased morbidity and mortality in cardiovascular patients.

METHODS

PubMed, Scopus, ISI and the Cochrane Library were systematically searched for observational and experimental studies assessing the occurrence of AKI in adult acute stroke patients submitted to EVT. Two independent reviewers collected study data regarding study setting, period, source of data, and AKI definition and predictors, the outcomes of interest being AKI incidence and 90-day death or dependency (modified Rankin Scale score ≥3). These outcomes were pooled using random effect models, and heterogeneity was measured using the I2 statistic.

RESULTS

22 studies were identified and included in the analysis, involving 32 034 patients. Pooled incidence of AKI was 7% (95% CI 5% to 10%), but heterogeneity was high across studies (I2=98%), and not accounted for by the definition of AKI used. The most frequently reported AKI predictors were impaired baseline renal function (5 studies) and diabetes (3 studies); 3 studies (2103 patients) reported data on death and 4 studies (2424 patients) reported data on dependency. Overall, AKI was associated with both outcomes, with ORs of 6.21 (95% CI 3.52 to 10.96) and 2.86 (95% CI 1.88 to 4.37), respectively. Heterogeneity was low for both analyses (I2=0%).

CONCLUSIONS

AKI affects 7% of acute stroke patients submitted to EVT and identifies a subgroup of patients for which treatment outcomes are suboptimal, with an increased risk of death and dependency.

Impact of contrast-enhanced versus non-contrast computed tomography on acute kidney injury in acute necrotizing pancreatitis: A randomized controlled trial

BACKGROUND

The data evaluating contrast-induced-acute kidney injury (AKI) in patients with acute pancreatitis is scarce. This study aimed to compare the frequency of AKI in patients with acute necrotizing pancreatitis undergoing non-contrast computed tomography (NCCT) with those undergoing contrast-enhanced computed tomography (CECT) during hospitalization.

METHODS

This prospective randomized controlled trial (CTRI/2019/12/022206) screened consecutive patients with acute pancreatitis for eligibility and randomly allocated patients with acute necrotizing pancreatitis (based on CECT in the first week of illness) and normal renal functions to receive either NCCT or CECT during hospitalization. The incidence of development of new AKI and clinical outcomes was compared between the two groups. Post-hoc analysis was done to adjust for disease severity.

RESULTS

As many as 105 patients completed the study as per protocol (NCCT = 45 and CECT = 60). AKI occurred in 36 (34.3%) patients, nine (20%) in the NCCT and 27 (45%) in the CECT group. Contrast induced-AKI occurred in 11 (18.3%) patients, while 25 had AKI secondary to acute pancreatitis. The relative risk (RR) of AKI in the CECT group was 2.25 (95% CI 1.17-4.30, p = .0142). The frequency of intensive care unit (ICU) admission (RR = 2.1, 95% CI 1.34-3.27, p = .0001) and need for drainage of collections (RR = 1.39, 95% CI 1.1-1.7, p = .005) was significantly higher and the length of hospitalization (p = .001) and ICU admission (p = 0.001) were significantly longer in the CECT group. However, when adjusted for the severity of acute pancreatitis, there was no difference in AKI and clinical outcomes between the NCCT and CECT groups. The duration of AKI was significantly longer and the need for dialysis was significantly higher in patients who had AKI secondary to acute pancreatitis compared to those with contrast induced-AKI (p = .003).

CONCLUSION

CECT is not significantly associated with AKI in acute necrotizing pancreatitis.

Blood pressure medication and acute kidney injury after intracerebral haemorrhage: an analysis of the ATACH-II trial

Background

Acute blood pressure (BP) reduction is standard of care after acute intracerebral haemorrhage (ICH). More acute BP reduction is associated with acute kidney injury (AKI). It is not known if the choice of antihypertensive medications affects the risk of AKI.

Methods

We analysed data from the ATACH-II clinical trial. AKI was defined by the Kidney Disease: Improving Global Outcomes criteria. We analysed antihypertensive medication from two sources. The first was a case report form that specified the use of labetalol, diltiazem, urapidil or other. We tested the hypothesis that the secondary medication was associated with AKI with χ2 test. Second, we tested the hypotheses the dosage of diltiazem was associated with AKI using Mann-Whitney U test.

Results

AKI occurred in 109 of 1000 patients (10.9%). A higher proportion of patients with AKI received diltiazem after nicardipine (12 (29%) vs 21 (12%), p=0.03). The 95%ile (90%-99% ile) of administered diltiazem was 18 (0-130) mg in patients with AKI vs 0 (0-30) mg in patients without AKI (p=0.002). There was no apparent confounding by indication for diltiazem use.

Conclusions

The use of diltiazem, and more diltiazem, was associated with AKI in patients with acute ICH.

Risk factors associated with contrast-associated acute kidney injury in ST-segment elevation myocardial infarction patients: a systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the risk factors for contrast-associated acute kidney injury (CA-AKI) in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched the databases of PubMed, Embase and Ovid, up to February 2022, for observational studies that investigated the association between risk factors and CA-AKI.

RESULTS

A total of 21 studies were included in the meta-analysis. Of the total 22 015 participants, 2728 developed CA-AKI. Pooled incidence was 11.91% (95% CI 9.69%, 14.14%). Patients with CA-AKI were more likely to be older, female, also had comorbidities (hypertension, diabetes, previous heart failure). Smoking (OR: 0.60; 95% CI 0.52, 0.69) and family history of CAD (coronary artery disease) (OR: 0.76; 95% CI 0.60, 0.95) were associated with lower risk of CA-AKI. Left anterior descending (LAD) artery occlusion (OR: 1.39; 95% CI 1.21, 1.59), left main disease (OR: 4.62; 95% CI 2.24, 9.53) and multivessel coronary disease (OR: 1.33; 95% CI 1.11, 1.60) were risk factors for CA-AKI. Contrast volume (weighted mean difference: 20.40; 95% CI 11.02, 29.79) was associated with increased risk in patients receiving iso-osmolar or low-osmolar non-ionic contrast.

CONCLUSIONS

In addition to the known risk factors, LAD artery infarction, left main disease and multivessel disease are risk factors for CA-AKI. The unexpected favourable association between smoking, as well as family history of CAD, and CA-AKI requires further investigation.

PROSPERO REGISTRATION NUMBER

CRD42021289868.

What you need to know about: imaging in patients with renal failure

Contrast-enhanced medical imaging is commonly requested in clinical practice. Contrast media provide better differentiation of tissue enhancement, improves the soft tissue contrast resolution, and enhances the ability to study the physiology and function of the organs and/or systems. However, contrast media may cause complications, especially in patients with renal failure. This article discusses the use of contrast media in common imaging modalities and the relationship between contrast media and renal function. Administration of iodinated contrast media in computed tomography may cause contrast-associated acute kidney injury; the risk factors and preventive strategies for this are elaborated in this article. Administration of gadolinium-based contrast media in magnetic resonance imaging may lead to nephrogenic systemic fibrosis. Therefore, precautions should be taken when planning for medical imaging for patients with pre-existing acute kidney injury or end-stage chronic kidney disease, for whom contrast media administration in computed tomography or magnetic resonance imaging may be relatively contraindicated. Alternatively, ultrasound contrast agents can be safely used in patients with acute kidney injury or chronic kidney disease. Clinical teams should discuss these patients with radiologists, taking into account the risk-benefits of contrast media, to determine the optimal imaging protocol or modality to answer the clinical query.

Best Practice Recommendations for Stroke Vascular Imaging During Iodinated Contrast Shortage

GE Healthcare© announced on April 19, 2022, that their main factory and distributor of iodinated contrast had experienced a temporary shutdown because of COVID-19 outbreak in Shanghai, China. This, along with other supply chain issues, led to a worldwide shortage of iodinated contrast agents, Omnipaque and Visipaque. Our Comprehensive Stroke Center was confronted with the cascading effect of this iodinated contrast material shortage. We took immediate steps to revise our protocols and processes to continue to provide high-quality care to our stroke patients. A multidisciplinary working group comprised of representatives of our stroke center, including vascular neurology, diagnostic neuroradiology, and neurovascular surgery, urgently met to brainstorm how to mitigate the shortage. We established parameters and local guidelines for the use of CT angiography, CT perfusion, and digital subtraction angiography for stroke patients. In this article, we propose "best practice" recommendations from a single Joint Commission approved Comprehensive Stroke Center that can be used as blueprint by other hospital systems when navigating potential future supply chain issues, to provide consistent high-quality stroke care.

Diagnosis, Workup, Risk Reduction of Transient Ischemic Attack in the Emergency Department Setting: A Scientific Statement From the American Heart Association

At least 240 000 individuals experience a transient ischemic attack each year in the United States. Transient ischemic attack is a strong predictor of subsequent stroke. The 90-day stroke risk after transient ischemic attack can be as high as 17.8%, with almost half occurring within 2 days of the index event. Diagnosing transient ischemic attack can also be challenging given the transitory nature of symptoms, often reassuring neurological examination at the time of evaluation, and lack of confirmatory testing. Limited resources, such as imaging availability and access to specialists, can further exacerbate this challenge. This scientific statement focuses on the correct clinical diagnosis, risk assessment, and management decisions of patients with suspected transient ischemic attack. Identification of high-risk patients can be achieved through use of comprehensive protocols incorporating acute phase imaging of both the brain and cerebral vasculature, thoughtful use of risk stratification scales, and ancillary testing with the ultimate goal of determining who can be safely discharged home from the emergency department versus admitted to the hospital. We discuss various methods for rapid yet comprehensive evaluations, keeping resource-limited sites in mind. In addition, we discuss strategies for secondary prevention of future cerebrovascular events using maximal medical therapy and patient education.

Comparison of multiple acupoints combination in the treatment of post-stroke cognitive impairment: A network meta-analysis

BACKGROUND

To evaluate the efficacy of multiple acupoint combinations for the treatment of post-stroke cognitive impairment (PSCI) using a network meta-analysis method.

METHODS

Searches for clinical randomized controlled trials (RCTs) of various types of acupuncture treatments for post-stroke cognitive dysfunction were conducted, data were extracted from studies selected according to the inclusion criteria, and the RCTs included in the analysis were assessed separately for risk of literature bias. Network meta-analysis was performed using Stata 14.0.

RESULTS

Sixteen RCTs involving 1257 patients were included, which involved 9 groups of acupoint treatment plans. The best treatment plan for improving the mini-mental state examination score of PSCI was a cephalic plexus spur (99.7%). The best treatment option for improving the montreal cognitive assessment score for PSCI was Zishen Yisui acupuncture therapy (ZSYSA) (77.3%). The best option for improving the barthel index score of PSCI was ZSYSA (99.2%). In terms of improving the overall clinical outcomes of PSCI, the best treatment option for improving the overall clinical effectiveness of PSCI is ZSYSA Therapy (92.2%).

CONCLUSION

The analysis of all results shows that ZSYSA can significantly improve PSCI compared to other acupuncture therapies.

STRENGTHS AND LIMITATIONS OF THIS STUDY

This is the 1st study on the treatment of PSCI with different acupoint combinations based on a network meta-analysis method, which provides a reference for clinical rehabilitation workers; all included studies were randomized controlled trials, which increased the reliability of this study. Limitations; The number of relevant clinical studies retrieved was too small, and all included clinical trials were located in China; therefore, there is a great possibility of publication bias; Most of the included studies did not clearly explain the random distribution mode, follow-up, distribution concealment, or other experimental conditions. Therefore, selection and reporting biases cannot be excluded, suggesting that the quality of the literature is not high; Because of the strict inclusion criteria, the number of studies was limited, and subgroup analysis could not be performed according to the time of onset and the length of the disease course.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

A risk score model of contrast-induced acute kidney injury in patients with emergency percutaneous coronary interventions

Background

The previously built score models of contrast-induced acute kidney injury (CI-AKI) were principally founded on selective percutaneous coronary intervention (PCI) cases. Our study was to form a risk score model of CI-AKI and make a temporal validation in a population who underwent emergency PCIs.

Methods

We included patients who underwent emergency PCIs from 2013 to 2018 and divided them into the derivation and validation cohorts. Logistic regression analysis was harnessed to create the risk model. In this research, we defined CI-AKI as an increase in serum creatinine (SCr) ≥0.5 mg/dL (44.2 μmol/L) above baseline within seven days following exposure to contrast medium.

Results

A total of 3564 patients who underwent emergency PCIs were enrolled and divided into the derivation (2376 cases) and validation cohorts (1188 cases), with CI-AKI incidence of 6.61 and 5.39%, respectively. By logistic analysis, the CI-AKI risk score model was constituted by 8 variables: female (1 point), history of transient ischemic attack (TIA)/stroke (1 point), left ventricular ejection fraction (LVEF) classification (1 point per class), big endothelin-1 (ET-1) classification (1 point per class), estimated glomerular filtration rate (eGFR) classification (1 point per class), intra-aortic balloon pump (IABP) application (1 point), left anterior descending (LAD) stented (1 point), and administration of diuretic (2 points). The patients could be further divided into three groups: low-risk, moderate-risk, and high-risk groups, in accordance with the risk scores of 3–6, 7–10, and ≥11 points, and to the CI-AKI rates of 1.4, 11.9, and 42.6%. The CI-AKI risk score model performed well in discrimination (C statistic = 0.787, 95% CI: 0.731–0.844) and calibration ability, and showed a superior clinical utility.

Conclusion

We developed a simple CI-AKI risk score model which performs well as a tool for CI-AKI prediction in patients who underwent emergency PCIs.

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.

Canadian Association of Radiologists Guidance on Contrast Associated Acute Kidney Injury

Iodinated contrast media (ICM) is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after ICM administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations. This revised guidance document was developed by a multidisciplinary CAR Working Group of radiologists and nephrologists, and summarizes changes in practice related to contrast administration, screening, and risk stratification since the last guideline. It reviews the scientific evidence for contrast associated AKI and provides consensus-based recommendations for its prevention and management in the Canadian healthcare context. This article is a joint publication in the Canadian Association of Radiologists Journal and Canadian Journal of Kidney Health and Disease, intended to inform both communities of practice.

Canadian Association of Radiologists Guidance on Contrast-Associated Acute Kidney Injury

Purpose

Iodinated contrast media is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after iodinated contrast administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow-up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations.

Information sources

Published literature, including clinical trials, retrospective cohort series, review articles, and case reports, along with expert opinions from radiologists and nephrologists across Canada.

Methods

The leadership of the CAR formed a working group of radiologists and nephrologists with expertise in contrast administration and patient management related to contrast-associated AKI. We conducted a comprehensive review of the published literature to evaluate the evidence about contrast as a cause of AKI, and to inform evidence-based recommendations. Based on the available literature, the working group developed consensus recommendations.

Key Findings

The working group developed 21 recommendations, on screening, choice of iodinated contrast media, prophylaxis, medication considerations, and post contrast administration management. The key changes from the 2012 guidelines were (1) Simplification of screening to a simple questionnaire, and not delaying emergent examinations due to a need for creatinine measurements (2) Prophylaxis considerations only for patients with estimated glomerular filtration rate (eGFR) less than 30 mL/min/1.73 m2 (3) Not recommending the routine discontinuation of any drugs to decrease risk of AKI, except metformin when eGFR is less than 30 mL/min/1.73 m2 and (4) Not requiring routine follow up serum creatinine measurements post iodinated contrast administration.

Limitations

We did not conduct a formal systematic review or meta-analysis. We did not evaluate our specific suggestions in the clinical environment.

Implications

Given the importance of iodinated contrast media use in diagnosis and management, and the low risk of AKI after contrast use, these guidelines aim to streamline the processes around iodinated contrast use in most clinical settings. As newer evidence arises that may change or add to the recommendations provided, the working group will revise these guidelines.

Early Diagnosis of Acute Ischemic Stroke by Brain Computed Tomography Perfusion Imaging Combined with Head and Neck Computed Tomography Angiography on Deep Learning Algorithm

The purpose of the research was to discuss the application values of deep learning algorithm-based computed tomography perfusion (CTP) imaging combined with head and neck computed tomography angiography (CTA) in the diagnosis of ultra-early acute ischemic stroke. Firstly, 88 patients with acute ischemic stroke were selected as the research objects and performed with cerebral CTP and CTA examinations. In order to improve the effect of image diagnosis, a new deconvolution network model AD-CNNnet based on deep learning was proposed and used in patient CTP image evaluation. The results showed that the peak signal-to-noise ratio (PSNR) and feature similarity (FSIM) of the AD-CNNnet method were significantly higher than those of traditional methods, while the normalized mean square error (NMSE) was significantly lower than that of traditional algorithms (P < 0.05). 80 cases were positive by CTP-CTA, including 16 cases of hyperacute ischemic stroke and 64 cases of acute ischemic stroke. The diagnostic sensitivity was 93.66%, and the specificity was 96.18%. The cerebral blood flow (CBF), cerebral blood volume (CBV), and the mean transit time (MTT) in the infarcted area were significantly greater than those in the corresponding healthy side area, and the time to peak (TTP) was significantly less than that in the corresponding healthy side area (P < 0.05). The cerebral perfusion parameters CBF, TTP, and MTT in the penumbra were significantly different from those in the infarct central area and the corresponding contralateral area, and TTP was the most sensitive (P < 0.05). To sum up, deep learning algorithm-based CTP combined with CTA could find the location of cerebral infarction lesions as early as possible to provide a reliable diagnostic result for the diagnosis of ultra-early acute ischemic stroke.

Renal impairment and the prognosis of endovascular thrombectomy: a meta-analysis and systematic review

Background

The association between renal impairment (RI) and stroke outcome after endovascular thrombectomy (EVT) remains unclear, which limits the estimation of patient prognosis by clinicians involved in EVT decision-making.

Purpose

This study aimed to investigate the association between RI and acute ischemic stroke (AIS) outcomes in patients treated with EVT.

Methods

Studies involving the association between RI at admission and AIS outcomes after EVT were retrieved from the PubMed and Embase databases from their inception to 17 January 2022. A fixed-effects model was used to synthesize the data of the included studies. Sensitivity analysis was performed to identify the source of heterogeneity.

Results

Overall, 11 studies, including 5053 patients with stroke receiving EVT, were included in the full analysis. In unadjusted analyses, RI was associated with 3-month poor functional outcome and mortality; the odds ratios (ORs) were 2.13 [10 studies; 95% confidence interval (CI), 1.77-2.56; I 2 = 45%] and 2.42 (8 studies; 95% CI, 2.02-2.90; I 2 = 58%), respectively. In adjusted analyses, the above associations remained significant; the OR of the 3-month poor functional outcome was 1.49 (5 studies; 95% CI, 1.17-1.90; I 2 = 58%), and the OR of the 3-month mortality was 1.84 (6 studies; 95% CI, 1.45-2.33; I 2 = 74%). Similar results were obtained in sensitivity analyses.

Conclusion

Our results suggest that in patients with AIS who underwent EVT, RI at admission was associated with 3-month poor functional outcome and mortality.

Post-Contrast Acute Kidney Injury after Acute Stroke-Insights from a German Tertiary Care Center

Background: Our aim was to investigate the relationship between additional iodinated contrast medium (CM) application for acute stroke imaging and Post-Contrast Acute Kidney Injury (PC-AKI). Methods: We performed a retrospective analysis of consecutive patients with acute stroke who received a CT angiogram (CTA) with or without additional CT perfusion (CTP) at admission between 2017 and 2020. The primary endpoint was the incidence of PC-AKI. Potential causes of renal function impairment were recorded and logistic regression was performed to determine predictors of PC-AKI. Results: Of 3134 cases screened, n = 989 met the predefined inclusion criteria. PC-AKI occurred in 22 (5.4%) patients who received CTA only and 18 (3.1%) patients who received CTA and additional CTP (unadjusted OR, CI; 0.59, 0.29–1.05). In 31/40 (77.5%) patients who suffered PC-AKI, a non-CM-related cause of renal function impairment was identified. Stroke etiology (hemorrhagic vs. ischemic) and indicators of prior kidney disease were independent predictors of PC-AKI. Conclusions: Additional administration of CM for perfusion imaging in acute stroke did not show a relevant influence on the occurrence of PC-AKI. Patients with intracranial hemorrhage and/or prior kidney disease are at particular risk of developing AKI.

Overview of Imaging Modalities in Stroke

PURPOSE OF THE REVIEW

This article reviews common imaging modalities used in diagnosis and management of acute stroke. Each modality is discussed individually and clinical scenarios are presented to demonstrate how to apply these modalities in decision-making.

RECENT FINDINGS

Advances in neuroimaging provide unprecedented accuracy in determining tissue viability as well as tissue fate in acute stroke. In addition, advances in machine learning have led to the creation of decision support tools to improve the interpretability of these studies.

SUMMARY

Noncontrast head computed tomography (CT) remains the most commonly used initial imaging tool to evaluate stroke. Its exquisite sensitivity for hemorrhage, rapid acquisition, and widespread availability make it the ideal first study. CT angiography (CTA), the most common follow-up study after noncontrast head CT, is used primarily to identify intracranial large vessel occlusions and cervical carotid or vertebral artery disease. CTA is highly sensitive and can improve accuracy of patient selection for endovascular therapy through delineations of ischemic core. CT perfusion is widely used in endovascular therapy trials and benefits from multiple commercially available machine-learning packages that perform automated postprocessing and interpretation. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) can provide valuable insights for outcomes prognostication as well as stroke etiology. Optical coherence tomography (OCT), positron emission tomography (PET), single-photon emission computerized tomography (SPECT) offer similar insights. In the clinical scenarios presented, we demonstrate how multimodal imaging approaches can be tailored to gain mechanistic insights for a range of cerebrovascular pathologies.

Acute Stroke Imaging Research Roadmap IV: Imaging Selection and Outcomes in Acute Stroke Clinical Trials and Practice

BACKGROUND AND PURPOSE

The Stroke Treatment Academic Industry Roundtable (STAIR) sponsored an imaging session and workshop during the Stroke Treatment Academic Industry Roundtable XI via webinar on October 1 to 2, 2020, to develop consensus recommendations, particularly regarding optimal imaging at primary stroke centers.

METHODS

This forum brought together stroke neurologists, neuroradiologists, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke, industry representatives, and members of the US Food and Drug Administration to discuss imaging priorities in the light of developments in reperfusion therapies, particularly in an extended time window, and reinvigorated interest in brain cytoprotection trials.

RESULTS

The imaging session summarized and compared the imaging components of recent acute stroke trials and debated the optimal imaging strategy at primary stroke centers. The imaging workshop developed consensus recommendations for optimizing the acquisition, analysis, and interpretation of computed tomography and magnetic resonance acute stroke imaging, and also recommendations on imaging strategies for primary stroke centers.

CONCLUSIONS

Recent positive acute stroke clinical trials have extended the treatment window for reperfusion therapies using imaging selection. Achieving rapid and high-quality stroke imaging is therefore critical at both primary and comprehensive stroke centers. Recommendations for enhancing stroke imaging research are provided.

Neuroimaging Considerations in Patients with Chronic Kidney Disease

Chronic Kidney Disease is a common medical condition that frequently overlaps with neurologic disease. Neuroimaging can be a useful tool to aid in the diagnoses of neurologic illness, including those that result from renal impairment. Some neuroimaging studies also have the potential to lead to adverse effects on the kidneys necessitating a thoughtful approach to selection of imaging modalities. In particular, multimodal imaging is becoming increasingly common in patients presenting with symptoms of acute stroke, a population that may be at higher risk for renal complications. This article will summarize the neuroimaging manifestations of conditions with shared renal and neurologic involvement and highlight considerations regarding the use of contrast media, nephrogenic systemic fibrosis, and metformin-associated lactic acidosis.

Chronic Kidney Disease and Cerebrovascular Disease: Consensus and Guidance From a KDIGO Controversies Conference

The global health burden of chronic kidney disease is rapidly rising, and chronic kidney disease is an important risk factor for cerebrovascular disease. Proposed underlying mechanisms for this relationship include shared traditional risk factors such as hypertension and diabetes, uremia-related nontraditional risk factors, such as oxidative stress and abnormal calcium-phosphorus metabolism, and dialysis-specific factors such as cerebral hypoperfusion and changes in cardiac structure. Chronic kidney disease frequently complicates routine stroke risk prediction, diagnosis, management, and prevention. It is also associated with worse stroke severity, outcomes and a high burden of silent cerebrovascular disease, and vascular cognitive impairment. Here, we present a summary of the epidemiology, pathophysiology, diagnosis, and treatment of cerebrovascular disease in chronic kidney disease from the Kidney Disease: Improving Global Outcomes Controversies Conference on central and peripheral arterial disease with a focus on knowledge gaps, areas of controversy, and priorities for research.

Cost-Effectiveness Study of Initial Imaging Selection in Acute Ischemic Stroke Care

PURPOSE

National guidelines recommend prompt identification of candidates for acute ischemic stroke (AIS) treatment, requiring timely neuroimaging with CT and/or MRI. CT is often preferred because of its widespread availability and rapid acquisition. Despite higher diagnostic accuracy of MRI, it commonly involves complex workflows that could potentially cause treatment time delays. The purpose of this study was to analyze the impact on outcomes of imaging utilization before treatment decisions at comprehensive stroke centers for patients presenting with suspected AIS in the anterior circulation with last-known-well-to-arrival time 0 to 24 hours.

METHODS

A decision simulation model based on the American Heart Association's recommendations for AIS care pathways was developed from a health care perspective to compare initial imaging strategies: (1) stepwise-CT: noncontrast CT (NCCT) at the time of presentation, with CT angiography (CTA) ± CT perfusion (CTP) only in select patients (initial imaging to exclude hemorrhage and extensive ischemia) for mechanical thrombectomy (MT) evaluation; (2) stepwise-hybrid: NCCT at the time of presentation, with MR angiography (MRA) ± MR perfusion (MRP) only for MT evaluation; (3) stepwise-advanced: NCCT + CTA at presentation, with MR diffusion-weighted imaging (MR DWI) + MRP only for MT evaluation; (4) comprehensive-CT: NCCT + CTA + CTP at the time of presentation; and (5) comprehensive-MR: MR DWI + MRA + MRP at the time of presentation. Model parameters were defined using evidence-based data. Cost-effectiveness and sensitivity analyses were performed.

RESULTS

The cost-effectiveness analyses revealed that comprehensive-CT and comprehensive-MR yield the highest lifetime quality-adjusted life-years (QALYs) (4.81 and 4.82, respectively). However, the incremental cost-effectiveness ratio of comprehensive-MR is $233,000/QALY compared with comprehensive-CT. Stepwise-CT, stepwise-hybrid, and stepwise-advanced strategies are dominated, yielding lower QALYs and higher costs compared with comprehensive-CT.

CONCLUSIONS

Performing comprehensive-CT at presentation is the most cost-effective initial imaging strategy at comprehensive stroke centers.

Acute Kidney Injury After CT in Emergency Patients with Chronic Kidney Disease: A Propensity Score-matched Analysis

INTRODUCTION

Acute kidney injury (AKI) after intravenous contrast administration for computed tomography (CT) occurs infrequently, but certain patients may be susceptible. This study evaluated AKI incidence among emergency department (ED) patients with pre-existing chronic kidney disease (CKD) undergoing CT exams.

METHODS

This retrospective cohort study in an integrated healthcare system included ED patients previously diagnosed with CKD stages 3-5 (estimated glomerular filtration rate <60 milliliters per minute per 1.73 meters squared over at least three months), undergoing CT exams with or without intravenous contrast, from January 1, 2013-December 31, 2017. We excluded patients with CT prior to (30 days) or following (14 days) index CT and missing serum creatinine (sCr) measurements. We applied propensity score matching, and then multivariable regression adjustment for post-CT ED disposition and ED diagnosis, to calculate adjusted risk of AKI. Secondary patient-centered outcomes included 30-day mortality, end-stage renal disease (ESRD) diagnosis, and dialysis initiation.

RESULTS

Among 103,573 eligible ED patients undergoing CT, propensity score matching yielded 5,589 pairs. Adjusted risk ratio (ARR) for AKI was higher overall for contrast-enhanced CT (1.60; 95% confidence interval [CI], 1.43-1.79). However, secondary outcomes were infrequent: 19/5,589 non-contrast vs 40/5,589 contrast patients with new dialysis initiation at 30 days (adjusted risk 0.3% vs 0.7%; adjusted risk reduction 0.4%; 95% CI, 0.1%-0.7%).

CONCLUSION

In ED patients with chronic kidney disease undergoing CT, intravenous contrast was associated with higher overall adjusted risk of AKI, but patient-centered secondary outcomes were rare. The clinical significance of transient kidney injury after CT is unclear, although patients with advanced chronic kidney disease appear to have elevated risk.

Acute Stroke Care for Patients with Chronic Kidney Disease

Chronic kidney disease is a common comorbidity in patients presenting to emergency departments with acute ischemic stroke. There are numerous considerations that must be taken into account in the acute diagnosis and management of these patients. CKD patients may have different stroke presentations compared to the general population that may make diagnosis more challenging. With the expanding use of endovascular thrombectomy for acute ischemic stroke, more contrasted studies are being employed as part of the acute evaluation, particularly in the identification of patients with large vessel occlusion and demonstration of salvageable penumbra. For most patients with renal dysfunction, studies such as CT angiography and perfusion may still be performed despite concerns of acute kidney injury. Although patient outcomes with reperfusion therapies such as intravenous alteplase and endovascular thrombectomy are not as robust as those seen within the general population, the available data supports utilization of these therapies among CKD patients. This article provides a review of the factors that must be considered in the acute management of the CKD patient presenting with acute ischemic stroke.

Effect of Race-Ethnicity and CT Angiography on Renal Injury During Blood Pressure Treatment for Intracerebral Hemorrhage

BACKGROUND

Lowering blood pressure intensively in acute intracerebral hemorrhage (ICH) is associated with adverse renal events; Blacks and Hispanics have a higher incidence of ICH and kidney disease than Whites. In addition, CT angiography (CTA), which may also be associated with acute kidney injury (AKI), is often done in acute ICH. Our objective was to investigate the relationship between aggressive BP management, CTA, race-ethnicity and the risk of developing AKI in patients presenting with ICH.

METHODS

We retrospectively calculated the difference between the highest and lowest systolic blood pressure during the first 24 h of admission in patients with spontaneous ICH over 30 months. Creatinine (Cr) levels at admission were compared to the highest Cr level during the first 7 days after admission. AKI was defined as any > 50% increase of baseline Cr during the first 7 days. Logistic regression models were used to assess the association between race-ethnicity and CTA and AKI. We also analyzed the incidence of AKI stratified by race-ethnicity.

RESULTS

A total of 394 patients were included (mean age ± SD 63 ± 14 years), 160 patients (41%) were women, 162 (41%) Hispanic, 39 (10%) White and 189 (48%) Black. Most of the patients underwent CTA (73%). The prevalence of AKI was (18%), but no difference was found in AKI incidence (19% in Blacks vs. 17% in Whites vs. 18% in Hispanics (p = 0.940). In fully adjusted models, AKI was not associated with race-ethnicity (p = 0.665) or CTA (p = 0.187). The stratified analysis by race-ethnicity did not change our findings.

CONCLUSION

We found no association between race-ethnicity or CTA and AKI during the acute management of ICH in a real-life stroke population. Our findings suggest that CTA can be safely obtained in acute ICH, even in populations of diverse race-ethnicity who may be more prone to adverse kidney events. CTA did not contribute to developing AKI.

[Therapeutics for acute tubular necrosis in 2020]

Acute kidney injury is a major cause of in-hospital morbidity and mortality because of the serious nature of the underlying illnesses and the high incidence of complications. The two major causes of acute kidney injury that occur in the hospital are prerenal disease and acute tubular necrosis. Acute tubular necrosis has a histological definition, even if a kidney biopsy is rarely performed. Kidney injuries occurring during acute tubular necrosis are underlined by different pathophysiological mechanisms that emphasize the role of hypoxia on the tubular cells such as apoptosis, cytoskeleton disruption, mitochondrial function and the inflammation mediated by innate immune cells. The microcirculation and the endothelial cells are also the targets of hypoxia-mediated impairment. Repair mechanisms are sometimes inadequate because of pro-fibrotic factors that will lead to chronic kidney disease. Despite all the potential therapeutic targets highlighted by the pathophysiological knowledge, further works remain necessary to find a way to prevent these injuries.

[Contrast medium-induced acute kidney injury-Consensus paper of the working group "Heart and Kidney" of the German Cardiac Society and the German Society of Nephrology]

This consensus paper summarizes the expert consensus and recommendations of the working group "Heart and Kidney" of the German Cardiac Society (DGK) and the German Society of Nephrology (DGfN) on contrast medium-induced acute kidney injury. Potentially nephrotoxic contrast agents containing iodine are frequently used in interventional medicine and for computer tomography diagnostics. Acute kidney injury occurs in approximately 8-17% of patients exposed to contrast media. The risk factors and underlying pathophysiology are discussed and recommendations for the prophylaxis and treatment of contrast medium-induced acute nephropathy are presented.

Contrast-induced acute kidney injury in acute ischaemic stroke patients

PURPOSE

The potential nephrotoxicity of intravenous iodinated contrast media is a major concern for acute ischaemic stroke imaging evaluation. This study aimed to assess the incidence of acute kidney injury after intravenous iodinated contrast media exposure in acute ischaemic stroke patients.

METHODS

We conducted a retrospective cohort analysis between January 2012 and July 2018 to select adult patients admitted to the emergency department with acute ischaemic stroke. The exposed patients received a uniform intravenous dose of low osmolar non-ionic iodinated contrast media, as part of the imaging protocol for acute ischaemic stroke. The unexposed patients underwent a non-enhanced cranial computed tomography scan. Acute kidney injury was defined according to the Kidney Disease Improving Global Outcomes criteria, limited to the first 72 hours.

RESULTS

A total of 161 and 105 patients were included in the exposed and unexposed groups, respectively. The median age was 72.8 years (interquartile range 20), 53% were men and 97% were white. Demographic and baseline characteristics were similar between the groups. The incidence of acute kidney injury between exposed (n = 10, 6.2%) and unexposed (n = 1, 1%) groups (P = 0.073) was similar and contrast exposure was not a significant predictor of acute kidney injury.

CONCLUSION

Intravenous iodinated contrast media exposure during acute ischaemic stroke imaging protocols is not an independent predictor of acute kidney injury in patients with normal or near-normal renal function. Studies with larger sample sizes would help to clarify if patients with both cardiovascular risk factors and impaired renal function could benefit from prophylactic measures.

Impact of multimorbidity on risk and outcome of stroke: Lessons from chronic kidney disease

With both an aging population and greater post-stroke survival, multimorbidity is a growing healthcare challenge, affecting over 40% of stroke patients, and rising rapidly and predictably with increasing age. Commonly defined as the co-occurrence of two or more chronic conditions, multimorbidity burden is a strong adverse prognostic factor, associated with greater short- and long-term stroke mortality, worse rehabilitation outcomes, and reduced use of secondary prevention. Chronic kidney disease can be considered as the archetypal comorbidity, being age-dependent and also affecting about 40% of stroke patients. Chronic kidney disease and stroke share very similar traditional cardiovascular risk factor profiles such as hypertension and diabetes, though novel chronic kidney disease-specific risk factors such as inflammation and oxidative stress have also been proposed. Using chronic kidney disease as an exemplar condition, we explore the mechanisms of risk in multimorbidity, implications for management, impact on stroke severity, and downstream consequences such as post-stroke cognitive impairment and dementia.

Impact of creatinine screening on contrast-induced nephropathy following computerized tomography for stroke

OBJECTIVE

This study sought to evaluate rates of acute kidney injury in patients undergoing contrast-enhanced computerized tomography for acute stroke in the emergency department (ED) before and after the cessation of creatinine screening.

METHODS

This retrospective study compared ED patients receiving contrast-enhanced imaging for suspected acute stroke with and without protocolized creatinine screening. The primary outcome was CIN, defined as an increase in serum creatinine of 0.3 mg/dl within 48 hours or 50% above baseline within 7 days after contrast administration. Secondary outcomes consisted of CIN based on other definitions, renal impairment greater than 30 days from contrast administration, hemodialysis, and mortality. Outcomes were compared using difference of proportions and odds ratios with 95% confidence intervals.

RESULTS

This study included 382 subjects, with 186 and 196 in the screening and post-screening cohorts, respectively. No significant differences were observed for CIN (7.0% vs 7.1%, difference 0.1% [95% CI -5.6-5.1%], OR 1.02 [95% CI 0.47-2.24]), renal impairment greater than 30 days post-contrast (8.4% vs 7.5%, OR 0.88 [0.38-2.07]), or mortality (index visit: 4.8% vs 2.6%, OR 0.51 [0.17-1.57], 90-day follow-up: 6.7% vs 4.0%, OR 0.58 [0.22-1.53]). No patients from either group required hemodialysis.

CONCLUSIONS

The elimination of creatinine screening prior to obtaining contrast-enhanced computerized tomography in patients with suspected acute stroke did not adversely affect rates of CIN, hemodialysis, or mortality at a comprehensive stroke center.

A New Scoring System for Prediction of Underlying Vascular Pathology in Patients with Intracerebral Hemorrhage: The Modified Secondary Intracerebral Hemorrhage Score

BACKGROUND

Secondary intracerebral hemorrhage (SICH) score is used to predict risk of intracranial hemorrhage (ICH) associated vascular lesions. However, it has low clinical utility in identifying patients without need for neurovascular imaging. This study aims to develop a modified scoring system to capture patients with low risk of underlying vascular pathology, thereby decreasing need for vascular imaging and its associated morbidity.

METHODS

A retrospective analysis of 994 patients with atraumatic ICH over 8 years was conducted, excluding known underlying pathology, subarachnoid hemorrhage, or lack of vascular imaging. Using a multivariate logistic regression model, independent predictors of vascular pathology were identified and utilized toward developing a modified Secondary Intracerebral Hemorrhage (mSICH) score.

RESULTS

Of 575 patients identified, 60 (10.4%) had underlying vascular etiology. Statistically significant predictors of vascular pathology included age; female sex; admission systolic blood pressure <160 mm Hg; locations other than basal ganglia, thalamus, pons, or midbrain; presence of high-risk imaging features; and proximity to large vessel-containing cisterns. The mSICH score correlated with an increasing incidence of vascular pathology [0-1 (0%), 9 (4.3%), 12 (9.7%), 21 (40.4%), 6 (33.3%), 8 (88.9%), and 4 (100%)] and had a significantly higher number of patients receiving scores with 0% incidence of vascular lesions compared with the SICH score [159 (27.6%) versus 12 (2.1%); P < 0.001)].

CONCLUSIONS

The mSICH score can more accurately predict risk of underlying vascular pathology of ICH and identify patients with lowest risk of vascular pathology. This may minimize the cost and associated risks of invasive cerebrovascular imaging.

Acute Kidney Injury after Endovascular Treatment in Patients with Acute Ischemic Stroke

Acute kidney injury (AKI) is often associated with the use of contrast agents. We evaluated the frequency of AKI, factors associated with AKI after endovascular treatment (EVT), and associations with AKI and clinical outcomes. We retrospectively analyzed consecutively enrolled patients with acute ischemic stroke who underwent EVT at three stroke centers in Korea. We compared the characteristics of patients with and without AKI and independent factors associated with AKI after EVT. We also investigated the effects of AKI on functional outcomes and mortality at 3 months. Of the 601 patients analyzed, 59 patients (9.8%) developed AKI and five patients (0.8%) started renal replacement therapy after EVT. In the multivariate analysis, diabetes mellitus (odds ratio (OR), 2.341; 95% CI, 1.283–4.269; p = 0.005), the contrast agent dose (OR, 1.107 per 10 mL; 95% CI, 1.032–1.187; p = 0.004), and unsuccessful reperfusion (OR, 1.909; 95% CI, 1.019–3.520; p = 0.040) were independently associated with AKI. The presence of AKI was associated with a poor functional outcome (OR, 5.145; 95% CI, 2.177–13.850; p < 0.001) and mortality (OR, 8.164; 95% CI, 4.046–16.709; p < 0.001) at 3 months. AKI may also affect the outcomes of ischemic stroke patients undergoing EVT. When implementing EVT, practitioners should be aware of these risk factors.

Contrast-Induced Acute Kidney Injury in Radiologic Management of Acute Ischemic Stroke in the Emergency Setting

BACKGROUND AND PURPOSE

The use of invasive cerebral angiography with CTA for active treatment of patients with suspected ischemic strokes has been increasing recently. This study aimed to identify the incidence of postcontrast acute kidney injury using baseline renal function when CTA and cerebral angiography were performed sequentially.

MATERIALS AND METHODS

This retrospective observational study evaluated adults (18 years of age or older) with ischemic stroke who underwent CTA and cerebral angiography sequentially between 2010 and 2018. The incidence of postcontrast acute kidney injury was determined using the baseline estimated glomerular filtration rate. The value of the baseline estimated glomerular filtration rate at which the occurrence of postcontrast acute kidney injury increased was also determined.

RESULTS

Postcontrast acute kidney injury occurred in 57/601 (9.5%) patients. Those with a baseline estimated glomerular filtration rate of <30 mL/min/1.73 m² showed a higher incidence of acute kidney injury. Age, chronic kidney disease, medication (nonsteroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, β blockers, statins, and insulin) use following contrast media exposure, and serum albumin affected the incidence of postcontrast acute kidney injury. The incidence of postcontrast acute kidney injury increased when the baseline estimated glomerular filtration rate was <43 mL/min/1.73 m².

CONCLUSIONS

Patients with low baseline renal function had the highest incidence of postcontrast acute kidney injury after CTA and cerebral angiography, but no fatal adverse effects were documented. Thus, patients suspected of having a stroke should be actively managed with respect to neurovascular function.

CTA measurements of acute lower gastrointestinal bleeding size predict subsequent positive catheter angiography

PURPOSE

The purpose of this study was to determine whether the measured size of active gastrointestinal hemorrhage was useful in predicting subsequent positive findings at catheter angiography.

MATERIALS AND METHODS

This was a single-institution retrospective study consisting of 32 patients with computed tomography angiography (CTA) positive for gastrointestinal bleeding who went on to receive catheter angiography. Each CTA was reviewed, with axial measurements of the anterior-posterior and transverse dimensions of the largest foci of hemorrhage recorded. Volumetric analysis was used to measure the volume of hemorrhage. These measurements were performed for both the arterial and portal venous phases. Additionally, the interval growth between the arterial and portal venous phase was also calculated.

RESULTS

There was a statistically significant difference in the absolute size of the maximum transverse dimension on portal venous phase imaging (mean = 19.8 mm, p < 0.001), as well as an interval increase in transverse (mean = 8.5 mm, p < 0.001) and anteriorposterior (mean = 5.4 mm, p = 0.027) size between arterial and portal venous phases in patients with positive catheter angiography versus negative catheter angiography. There was a statistically significant difference in the volume of hemorrhage on arterial (mean = 1.72 cm³, p = 0.020) and portal venous phases (mean = 5.89 cm³, p = 0.016), as well as an interval change in the size of hemorrhage between the two phases (mean = 4.17 cm³, p = 0.020) in patients with positive catheter angiography versus patients in the negative catheter angiography group.

CONCLUSIONS

The absolute axial size and volume of hemorrhage, as well as the interval change between the arterial and portal venous phases of CTA imaging is predictive of subsequent positive catheter angiography.

Incidence of Acute Kidney Injury After Computed Tomography Angiography±Computed Tomography Perfusion Followed by Thrombectomy in Patients With Stroke Using a Postprocedural Hydration Protocol

Background The risk of contrast-induced acute kidney injury (AKI) in patients with stroke receiving both computed tomography (CT) angiography and mechanical thrombectomy has been investigated only in small case series. No studies have investigated whether additional CT perfusion or chronic kidney disease (CKD) are associated with higher rates of AKI. Methods and Results Retrospective analysis of the AKI incidence in 1089 consecutive patients receiving CT angiography and mechanical thrombectomy from 2015 to 2017 and in subgroups with CKD (n=99) and CT perfusion (n=104) was performed. Patients received a standardized hydration protocol. Data on kidney function after mechanical thrombectomy were available in 1017 patients. A total of 59 (5.8%) patients developed AKI, and only 4 (6.8%) patients needed hemodialysis, all with known CKD. Patients with AKI significantly more often had known CKD (20.3% versus 8.4%, P=0.002), diabetes mellitus (33.9% versus 20.9%, P=0.018), and tandem occlusion (32.2% versus 16.2%, P=0.003) and a significantly higher in-hospital mortality (20.3% versus 7.0%, P<0.001) compared with patients without AKI. However, there were no significant independent predictors for AKI in multivariable logistic regression analysis. Sex (odds ratio [OR], 2.03; 95% CI, 1.17-3.52 [P=0.012]), higher National Institutes of Health Stroke Scale (OR, 1.10; 95% CI, 1.05-1.14 [P<0.001]), AKI (OR, 3.52; 95% CI, 1.63-7.64 [P=0.001]), diuretic use (OR, 1.80; 95% CI, 1.02-3.19), futile or incomplete recanalization (OR, 0.19; 95% CI, 0.09-0.40 [P<0.001]), and total volume of contrast agent volume (OR, 1.007; 95% CI, 1.002-1.011 [P=0.004]) were independently associated with in-hospital death. Two thirds of the patients with AKI died of severe brain damage and not AKI itself. Conclusions Post-contrast AKI rarely occurs in patients with stroke receiving a contrast agent for CT angiography/CT perfusion and subsequent mechanical thrombectomy. Patients with known CKD had higher rates of AKI and only these patients needed hemodialysis, but CKD was not independently associated with AKI or in-hospital mortality.

Brain-kidney interaction: Renal dysfunction following ischemic stroke

Stroke is a leading cause of mortality and morbidity, with long-term debilitating effects. Accumulating evidence from experimental studies as well as observational studies in patients suggests a cross talk between the brain and kidney after stroke. Stroke may lead to kidney dysfunction which can adversely impact patient outcome. In this review article, we discuss the epidemiology and mechanisms of brain–kidney interaction following ischemic stroke. Specifically, we discuss the role of the central autonomic network, autoregulation, inflammatory and immune responses, the role of extracellular vesicles and their cargo microRNA, in mediating brain–kidney interaction following stroke. Understanding the bidirectional nature of interaction between the brain and kidney after cerebral injury would have clinical implications for the treatment of stroke and overall patient outcome.

Benefits and Risks of CT Angiography Immediately after Emergency Arrival for Patients with Intracerebral Hematoma

Computed tomography angiography (CTA) immediately after diagnosis of intracerebral hematoma (ICH) on noncontrast CT in the emergency room has benefits, which consist of early diagnosis of secondary ICH and prediction of hematoma growth using the spot sign in primary ICH, but CTA also involves possible risks of acute kidney injury (AKI) and adverse reactions. The purpose of this study was to evaluate the benefits and risks of CTA. A total of 1423 consecutive adult patients diagnosed with ICH who were admitted within 3 days of onset between 2010 and 2017 were retrospectively analyzed. Of 1082 patients undergoing CTA, 162 patients (15.0%) showed secondary ICH, and the sensitivity of CTA for secondary ICH was 95.7%. Of 920 patients with primary ICH, a logistic regression model using the spot sign and four other previously reported risk factors (antiplatelet agents, anticoagulants, interval from onset to arrival, hematoma volume) with an area under the curve (AUC) of 0.787 significantly improved model performance to predict hematoma growth compared with a model using the same four factors without the spot sign (AUC: 0.697) (DeLong’s test: P = 0.0002). Rates of AKI occurrence were 9.0% and 9.8% in patients with and without CTA, respectively. The odds ratio of AKI in patients with CTA adjusted by reported risk factors was 1.16 (95% confidence interval: 0.72–1.95, P = 0.5548). Emergency CTA following noncontrast CT in patients with ICH could be useful for early diagnosis of secondary ICH and prediction of hematoma growth using the spot sign in primary ICH with little risk.

Emergency management of stroke in the era of mechanical thrombectomy

Emergency management of stroke has been directed at the delivery of recombinant tissue plasminogen activator (tPA) in a timely fashion. Because of the many limitations attached to the delivery of tPA and the perceived benefits accrued to tPA, its use has been limited. Mechanical thrombectomy, a far superior therapy for the largest and most disabling strokes, large vessel occlusions (LVOs), has changed the way acute strokes are managed. Aside from the rush to deliver tPA, there is now a need to identify LVO and refer those patients with LVO to physicians and facilities capable of delivering urgent thrombectomy. Other parts of emergency department management of stroke are directed at identifying and mitigating risk factors for future strokes and at preventing further damage from occurring. We review here the most recent literature supporting these advances in stroke care and present a framework for understanding the role that emergency physicians play in acute stroke care.

Single Centre Experience on Decision Making for Mechanical Thrombectomy Based on Single-Phase CT Angiography by Including NCCT and Maximum Intensity Projection Images - A Comparison with Magnetic Resonance Imaging after Non-Contrast CT

Objective

The purpose of this study was to suggest that computed tomography angiography (CTA) is valuable as the only preliminary examination for mechanical thrombectomy (MT). MT after single examination of CTA including non-contrast computed tomography (NCCT) and maximum intensity projection (MIP) improves door-to-puncture time as well as results in favorable outcomes.

Methods

A total of 157 patients who underwent MT at Dong Kang Medical Center from April 2015 to March 2019 were divided into two groups based on the examination performed prior to MT : CTA group who underwent CTA with NCCT and MIP, and NCCT+magnetic resonance image (MRi) group who underwent MRI including perfusion images after NCCT. In the two groups, time to CTA imaging or NCCT+MRi imaging after symptom onset, and time to arterial puncture and reperfusion were characterized as time-related outcomes. The evaluation of vascular recanalization after MT was defined as a modified thrombolysis in cerebral infarction (mTICI) scale. National Institutes of Health Stroke Scale (NIHSS) was assessed at the time of the visit to the emergency room and modified Rankin Scale (mRS) was assessed after 90 days.

Results

Typically, there were 34 patients in the CTA group and 33 patients in the NCCT+MRi group. A significantly shorter delay for door-to-puncture time was observed (mean, 86±22.1 vs. 176±47.5 minutes; p<0.01). Also, a significantly shorter door-to-imege time in the CTA group was observed (mean, 13±6.8 vs. 93±30.8 minutes; p<0.01). Moreover, a significantly shorter onset-to-puncture time was observed (mean, 195±128.0 vs. 314±157.6 minutes; p<0.01). Reperfusion result of mTICI ≥2b was 100% (34/34) in the CTA group and 94% (31/33) in the NCCT+MRi group, and mTICI 3 in 74% (25/34) in the CTA group and 73% (24/33) in the NCCT+MRi group. Favorable functional outcomes (mRS score ≤2 at 90 days) were 68% (23/34) in the CTA group and 60% (20/33) in the NCCT+MRi group.

Conclusion

A single-phase CTA including NCCT and MIP images was performed as a single preliminary examination, which led to a reduction in the time of the procedure and resulted in good results of prognosis. Consequently, it is concluded that this method is of sufficient value as the only preliminary examination for decision making.

Contrast-induced nephropathy: A dilemma between loss of neurons or nephrons in the setting of endovascular treatment of acute ischemic stroke

PURPOSE

The aim is to report the incidence and risk factors of contrast-induced nephropathy after the use of iodine-based contrast for the endovascular treatment of acute ischemic stroke.

METHODS

Data from patients who underwent neuroendovascular procedures in a center over a period of 22 months were analysed retrospectively. Contrast-induced nephropathy was determined by an increase in serum creatinine level of >25% of baseline or an absolute increase in serum creatinine level of at least 44 µmol/L (0.50 mg/dL) occurring after intravascular administration of contrast media without alternative explanation. The primary outcome measure of this study was the presence of contrast-induced nephropathy in these treated patients. Continuous data were presented as mean ± standard deviation, and categorical data as frequencies or percentages. The comparison was made using Student's t-test or Fisher's test. Logistic regression was performed to find independent contrast-induced nephropathy predictors. All statistical analyses were performed using Microsoft Excel. A p value of less than 0.05 was considered statistically significant.

RESULTS

One hundred and eighty-nine patients undergoing endovascular treatment for acute ischemic stroke. Twenty cases of the total cohort (n = 189) presented contrast-induced nephropathy (10.58%). Only diabetes and creatinine levels between 1.3 and 2.5 mg/dL were associated with contrast-induced nephropathy. No patient was treated with dialysis.

CONCLUSION

Contrast-induced nephropathy is a relatively common complication after endovascular treatment of acute ischemic stroke and is associated with worse outcome in patients with this condition. However, there is no increase in the frequency of hemodialysis after the use of iodinated contrast medium.

Intravascular Iodinated Contrast Is an Independent Cause of Acute Kidney Injury Following Coronary Angiography

OBJECTIVES

Recent studies have questioned whether intravascular iodinated contrast remains an independent cause of acute kidney injury (AKI). We sought to assess whether iodinated contrast administered during coronary angiography is an independent cause of AKI.

METHODS

We identified all of the patients who underwent coronary angiography between July 1, 2015 and June 30, 2017 with a discharge diagnosis of AKI that developed within 7 days following angiography. Using chart review, we categorized patients as having multifactorial AKI if ≥1 insults other than intravascular contrast potentially contributed to kidney injury or contrast-induced AKI (CI-AKI) if the only insult was contrast administration. We compared the severity of AKI and renal function upon discharge between patients with CI-AKI and multifactorial AKI.

RESULTS

We identified 78 patients who experienced AKI within 7 days following angiography, 10 (13%) of whom had CI-AKI and 68 of whom (87%) experienced multifactorial AKI. Nine (90%) patients with CI-AKI manifested stage 1 disease, 1 (10%) had stage 2 disease, and 9 (90%) experienced full recovery of kidney function. More patients with multifactorial AKI developed stage 2 or 3 disease (42% vs 10%, χ² = 3.73, P = 0.05) and experienced either partial recovery of kidney function or persistent kidney impairment compared with patients with CI-AKI (25% vs 10%, χ² = 1.9, P = 0.17), although the latter comparison was not statistically significant.

CONCLUSIONS

The intravascular administration of iodinated contrast remains an independent cause of AKI. Compared with those with multifactorial AKI, patients with CI-AKI appear to be more likely to experience mild decrements in kidney function that recover completely.

Incidence and risk of dialysis therapy within 30 days after contrast enhanced computed tomography in patients coded with chronic kidney disease: a nation-wide, population-based study

Background

Patients with chronic kidney disease (CKD) are considered at risk of contrast-induced acute kidney injury and possible subsequent need for dialysis therapy. Computed tomography (CT) is the most commonly performed examination requiring intravenous iodinated contrast media (ICM) injection. The actual risk of dialysis in CKD patients undergoing CT with ICM remains controversial. Furthermore, it is also uncertain whether these at-risk patients can be identified by means of administrative data. Our study is conducted in order to determine the incidence and risk of dialysis within 30 days after undergoing contrast enhanced CT in CKD coded patients.

Methods

This longitudinal, nation-wide, populated-based study is carried out by analyzing the Taiwan National Health Insurance Research Database retrospectively. Patients coded under the diagnosis of CKD who underwent CT are identified within randomly selected one million subjects of the database. From January 2012 to December 2013, 487 patients had undergone CT with ICM. A total of 924 patients who underwent CT without ICM are selected as the control group. Patients with advanced CKD or intensive care unit (ICU) admissions are assigned to the subgroups for analysis. The primary outcome is measured by dialysis events within 30 days after undergoing CT scans. The cumulative incidence is assessed by the Kaplan–Meier method and log-rank test. The risk of 30-day dialysis relative to the control group is analyzed by the Cox proportional hazards model after adjusting for age, sex, and baseline comorbidities.

Results

The numbers and percentages of dialysis events within 30 days after undergoing CT scans are 20 (4.1%) in the CT with ICM group and 66 (7.1%) in the CT without ICM group (p = 0.03). However, the adjusted hazard ratio (aHR) for 30-day dialysis was 0.84 (95% CI [0.46–1.54], p = 0.57), which is statistically non-significant. In both advanced CKD and ICU admission subgroups, there are also no significant differences in 30-day dialysis risks with the aHR of 1.12 (95% CI [0.38–3.33], p = 0.83) and 0.95 (95% CI [0.44–2.05], p = 0.90), respectively.

Conclusions

Within 30 days of receiving contrast-enhanced CT scans, 4.1% of CKD coded patients required dialysis, which appear to be lower compared with subjects who received non-contrast CT scans. However, no statistically significant difference is observed after adjustments are made for other baseline conditions. Thereby, the application of administrative data to identify patients with CKD cannot be viewed as a risk factor for the necessity to undergo dialysis within 30 days of receiving contrast-enhanced CT scans.