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

Perfusion Parameter Map Generation from 3 Phases of Computed Tomography Perfusion in Stroke Using Generative Adversarial Networks

Computed tomography perfusion (CTP) plays a crucial role in guiding reperfusion therapy and patient selection for acute ischemic stroke (AIS) through perfusion parameter maps of the brain; however, its widespread use is limited by the complexity of acquisition protocols and high radiation dose. Previous studies have attempted to reduce radiation exposure by equally lowering the temporal sampling rate; however, it may miss the peak of arterial enhancement, leading to underestimation of blood flow parameter. Here, we investigate the feasibility of using a generative adversarial network (GAN) to generate perfusion maps from 3 phases of CTP (mCTP). The three phases were chosen based on the multiphase computed tomography angiography scanning protocol: the peak arterial input function phase, the peak venous output function phase, and the delayed venous output function phase. The findings demonstrate that the GAN model achieved high visual overlap and performance for cerebral blood flow and time-to-maximum maps, with a mean structural similarity index measure of 0.921 to 0.971 and 0.817 to 0.883, a mean normalized root mean squared error of 0.019 to 0.108 and 0.058 to 0.064, and a mean learned perceptual image patch similarity of 0.039 to 0.088 and 0.141 to 0.146, respectively. For the 2 external datasets, the volume agreement between the model- and CTP-derived infarct and hypoperfusion areas was the intraclass correlation coefficient of 0.731 to 0.883 and 0.499 to 0.635, and the Spearman correlation coefficient of 0.720 to 0.808 and 0.533 to 0.6540, respectively. Qualitative assessments of diagnostic quality further confirmed that the mCTP-derived maps were comparable to those obtained from traditional CTP. In conclusion, the GAN-based model is effective in generating perfusion maps from mCTP, which could serve as a viable alternative to traditional CTP in the diagnostic evaluation of AIS.

Risk factors of acute kidney injury during hospitalization in acute ischaemic stroke patients undergoing mechanical thrombectomy

Introduction

Acute kidney injury (AKI) seems to worsen the prognosis of acute ischaemic stroke (AIS) patients treated with mechanical thrombectomy (MT). At the same time, the procedure of MT increases AKI risk by iodinated contrast use. Identification of factors predisposing to AKI after MT is important for recognizing vulnerable patients and successful prevention.

Aim

To identify factors associated with the occurrence of AKI during hospitalization in MT-treated AIS patients.

Material and methods

The study included all AIS patients treated with MT in the University Hospital in Krakow from 2019 to 2021. The diagnosis of AKI during hospitalisation was based on serum creatinine concentration levels, according to the Kidney Disease Improving Global Outcomes guidelines. We compared patients with and without AKI in terms of age, sex, comorbidities, stroke course and laboratory test results at admission. We identified factors associated with the occurrence of AKI using univariate logistic regression analysis, with significant variables subsequently added to the multivariate analyses.

Results

Among 593 MT-treated AIS patients the incidence of AKI during hospitalisation was 12.6%. AKI development was associated with diabetes, chronic kidney disease, total volume of iodinated contrast obtained during hospitalisation, posterior circulation stroke, lack of intravenous thrombolysis, and laboratory test results at admission: haemoglobin, glucose, urea, potassium, and creatinine. Total contrast volume and urea level were the most important independent risk factors associated with occurrence of AKI.

Conclusions

AKI is common in MT-treated AIS patients. There is a need to establish a protocol for decreasing the risk of AKI in AIS patients undergoing MT and, in case it occurs, a procedure for its treatment.

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.

Baseline eGFR cutoff for increased risk of post-contrast acute kidney injury in patients undergoing percutaneous coronary intervention for ST-elevation myocardial infarction in the emergency department

Acute myocardial infarction is an acute-stage disease that requires prompt diagnosis and treatment. Primary percutaneous coronary intervention (pPCI) for ST-elevation myocardial infarction (STEMI) is a high-risk factor for post-contrast acute kidney injury (PC-AKI). This retrospective cohort study analyzed the data of 754 patients with STEMI who underwent pPCI and were integrated into the Fast Interrogation Rule for STEMI critical pathway program between 2015 and 2019. We aimed to determine the optimal cutoff baseline eGFR for identifying a high risk of PC-AKI after multivariable adjustment with statistically significant risk factors. We also compared the incidence rates of PC-AKI between the previous and current diagnostic criteria. The probability of PC-AKI increased when the baseline estimated glomerular filtration rate (eGFR) was ≤ 79mL/min/1.73 m2. The optimal cutoff baseline eGFR for high risk of PC-AKI was found to be an eGFR of ≤ 61 mL/min/1.73 m2 after multivariable adjustment. The current diagnostic criteria more accurately identified the patient group with impaired renal function. Our results have clinically significant implications for identifying patients at a high risk of developing PC-AKI, especially before and after the use of contrast agents in patients who require PCI for STEMI in the emergency department.

Changes in blood and renal function in patients after cerebral digital subtraction angiography

Objective

Describe the incidence of contrast-induced acute renal injury (CI-AKI) and the changes in hematocrit in a cohort of patients undergoing elective cerebral digital subtraction angiography (DSA).

Methods

In this prospective study, patients undergoing cerebral DSA were assessed for hematocrit level and CI-AKI risk factors before the procedure and for developing CI-AKI 72 h after exposure to the contrast media.

Results

Among 215 patients (109 men, mean age 36.6 years). The most frequently found CI-AKI risk factor was hypertension. There were no cases of permanent renal impairment after 14 days. Significant changes were observed in hematocrit (45.7 ± 4.9, vs. 44.5 ± 4.6, p = 0.001), estimated creatinine clearance (129.7 ± 48.3, vs. 123.1 ± 40.5, p = 0.002), and serum creatinine (0.72 ± 0.19, vs 0.74 ± 0.18, p = 0.031). The mean change in serum creatinine 72 h after contrast administration was +0.27 ± 0.10 mg/dL (p < 0.05).

Conclusions

The incidence of CI-AKI after elective cerebral DSA was 1.4%. A significant decrease in hematocrit was observed up to 72 h after the procedure.

Early Acute Kidney Injury in Patients with Non-Traumatic Subarachnoid Hemorrhage who Undergo Catheter Angiography: Incidence, Associated Risk Factors and Impact on Outcome

OBJECTIVES

After subarachnoid hemorrhage (SAH), potential renal insults are numerous but the burden of early acute kidney injury (AKI) is unclear. We determined its incidence, rate of persistence, risk factors, and impact on patients' outcomes.

MATERIALS AND METHODS

Patients with non-traumatic SAH were retrospectively included if they underwent catheter angiography within the 48 h after their admission to the intensive care unit. Early AKI was defined according to Kidney Disease Improving Global Outcome (KDIGO) criteria, analyzed from the time of catheter angiography. Early AKI was considered as persistent if the KDIGO stage did not decrease between the 48th and the 60th hour.

RESULTS

Among 499 consecutive patients, early AKI (mostly oliguria) occurred in 132 (26%): stage 1, 2 and 3 in 72 (14%), 44 (9%), and 16 (3%) patients, respectively. It persisted in 36% of cases. Early AKI occurred more likely when SAH was severe or renal function was impaired at hospital admission: adjusted odds ratio of 2.76 [95% 1.77-4.30] and 3.32 [1.17-9.46], respectively. ICU and hospital lengths of stay were longer in patients who developed early AKI than in patients who did not: 16 [9-29] versus 12 [4-24] days (p = 0.0003) and 21 [14-43] versus 16 [11-32] days (p = 0.007), respectively. There was an independent link between early AKI and renal outcome (n = 274 in the model) but not with hospital mortality (n = 453).

CONCLUSIONS

One quarter of our population developed early AKI, mostly oliguria. It persisted beyond the 48th hour in one third of cases. The associated risk factors we identified were non-modifiable.

A systematic review of the incidence of hypersensitivity reactions and post-contrast acute kidney injury after ioversol: part 2-intra-arterial administration

Objectives

To evaluate the incidence of adverse drug reactions (ADRs), including hypersensitivity reactions (HSRs) and post-contrast acute kidney injury (PC-AKI), after intra-arterial (IA) administration of ioversol.

Methods and materials

A systematic literature search was performed (1980–2021) and studies documenting IA use of ioversol, and reporting safety outcomes were selected. Key information on study design, patients’ characteristics, indication, dose, and type of safety outcome were extracted.

Results

Twenty-eight studies (including two pediatric studies) with 8373 patients exposed to IA ioversol were selected. Studies were highly heterogenous in terms of design, PC-AKI definition, and studied population. PC-AKI incidence after coronary angiography was 7.5–21.9% in a general population, 4.0-26.4% in diabetic patients, and 5.5–28.9% in patients with chronic kidney disease (CKD). PC-AKI requiring dialysis was rare and reported mainly in patients with severe CKD. No significant differences in PC-AKI rates were shown in studies comparing different iodinated contrast media (ICM). Based on seven studies of ioversol clinical development, the overall ADR incidence was 1.6%, comparable to that reported with other non-ionic ICM. Pediatric data were scarce with only one study reporting on PC-AKI incidence (12%), and one reporting on ADR incidence (0.09%), both after coronary angiography.

Conclusions

After ioversol IA administration, PC-AKI incidence was highly variable between studies, likely reflecting the heterogeneity of the included study populations, and appeared comparable to that reported with other ICM. The rate of other ADRs appears to be low. Well-designed studies are needed for a better comparison with other ICM.

Key Points

• PC-AKI incidence after IA administration of ioversol appears to be comparable to that of other ICM, despite the high variability between studies.

• The need for dialysis after IA administration of ioversol is rare.

• No obvious difference was found regarding the safety profile of ioversol between IA and IV administration.

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.

Role of imaging in early diagnosis of acute ischemic stroke: a literature review

Stroke is a serious health condition that is responsible for more than 5% of total deaths. Near 20% of patients experiencing stroke die every year, resulting in the stroke being at the top of the list of preventable causes of death. Once an acute stroke is suspected, a golden hour of less than an hour is available to prevent the undesirable consequences. Since neuroimaging is mandatory in the diagnosis of stroke, the proper use of neuroimaging could help saving time and planning the right treatment for the patient. Some of the available imaging methods help us with rapid results, while others benefit us from a more accurate diagnosis. Hereby, we aim to provide a clinical review of the advantages and disadvantages of different available neuroimaging methods in approaching acute stroke to help clinicians choose the best method according to the settings.

Collateral estimation by susceptibility-weighted imaging and prediction of functional outcomes after acute anterior circulation ischemic stroke

To determine the value of susceptibility-weighted imaging (SWI) for collateral estimation and for predicting functional outcomes after acute ischemic stroke. To identify independent predictors of favorable functional outcomes, age, sex, risk factors, baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline diffusion-weighted imaging (DWI) lesion volume, site of steno-occlusion, SWI collateral grade, mode of treatment, and successful reperfusion were evaluated by multiple logistic regression analyses. A total of 152 participants were evaluated. A younger age (adjusted odds ratio (aOR), 0.42; 95% confidence interval (CI) 0.34 to 0.77; P < 0.001), a lower baseline NIHSS score (aOR 0.90; 95% CI 0.82 to 0.98; P = 0.02), a smaller baseline DWI lesion volume (aOR 0.83; 95% CI 0.73 to 0.96; P = 0.01), an intermediate collateral grade (aOR 9.49; 95% CI 1.36 to 66.38; P = 0.02), a good collateral grade (aOR 6.22; 95% CI 1.16 to 33.24; P = 0.03), and successful reperfusion (aOR 5.84; 95% CI 2.08 to 16.42; P = 0.001) were independently associated with a favorable functional outcome. There was a linear association between the SWI collateral grades and functional outcome (P = 0.008). Collateral estimation using the prominent vessel sign on SWI is clinically reliable, as it has prognostic value.