Incidence and Risk Factors for Acute Transient Contrast‐Induced Neurologic Deficit: A Systematic Review With Meta‐Analysis

BACKGROUND After MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) demonstrated that endovascular therapy improved outcomes in patients with stroke, the number of endovascular procedures has risen sharply. We describe acute transient contrast‐induced neurological deficit (ATCIND), a group of neurological syndromes associated with arterial contrast administration during angiography. Our goal is to elucidate the incidence, risk factors, outcomes, pathogenesis, and diagnostic characteristics of ATCIND. Our primary objective is to elucidate the incidence of ATCIND in the setting of coronary or cerebral angiography. Secondary outcomes include potential risk factors, demographics, treatment modalities, and patient recovery. METHODS The data that support the findings of this study are available from the corresponding author on reasonable request. The databases of the Cochrane Library, MEDLINE, Web of Science, and Embase were queried, yielding studies from 1974 to 2021. Inclusion criteria for articles were the following: (1) contrast‐induced encephalopathy, contrast‐induced neurotoxicity, or cortical blindness after contrast administration during angiography were the focus of the article; (2) incidence was reported; (3) studies included ≥3 cases; and (4) follow‐up tests were described to rule out other causes. Exclusion criteria included the following: (1) incidence was not reported; (2) unavailable in the English language; (3) abstracts and unpublished studies; and (4) did not exclude other possible causes, or findings suggested other possible causes, such as worsening ischemic injury. Of 627 articles, 7 were retained. This systematic review with meta‐analysis was performed in accordance with guidelines provided by the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) and the Meta‐Analysis of Observational Studies in Epidemiology (MOOSE) checklists. Independent extraction by multiple reviewers was performed. Data were pooled using a random‐effects model. RESULTS The primary study outcome was incidence of ATCIND, which was formulated before data collection began. We hypothesized that the pooled incidence of ATCIND would be similar to that of individual studies. A total of 70 of 21007 patients had the diagnosis of contrast‐induced encephalopathy, contrast‐induced neurotoxicity or angiography‐associated cortical blindness, and ATCIND. The incidence rate of ATCIND is estimated to be 0.51% (CI, 0.3%–1.0%; P <0.001 [ I 2 =29.3]), or 51 per 10 000 patients. Pooled data for risk factors for contrast‐induced encephalopathy were higher contrast dose (odds ratio [OR], 1.072; 95% CI, 0.952–1.192 [ P <0.001]; I 2 =0), and prior stroke (OR, 5.153; CI 1.726–8.581 [ P =0.003]; I 2 =0). Contrast dose >150 mL was a positive, significant predictor of visual disturbance (OR, 7.083; CI, 1.1742–42.793 [ P =0.033]). Full recovery is estimated at 89.5% (95% CI, 76.9%–95.6%; P <0.001 [ I 2 =0]). CONCLUSIONS This study confirms the rare incidence of ATCIND, although it shows moderate heterogeneity, likely reflecting the type of angiography performed. Risk factors include larger contrast dose and prior stroke. Full recovery occurs in the majority of patients. It should remain in the differential diagnosis in patients with certain risk factors for blood–brain barrier compromise.

Editorial: State of the Art CT and Image Quality, Radiation and Contrast Dose

A special issue of the journal Dose-Response entitled “State of the Art CT and Image Quality, Radiation and Contrast Dose” is proposed. Technological improvements on CT scanners have the potentiality to reduce the issues related to ionizing radiation administration, opening new insights toward innovative applications also thanks to the contamination of other research fields like artificial intelligence algorithms and additive manufacturing technologies. In order to approach these new research directions, a multidisciplinary team becomes needed, overcoming the clinical and radiological point of view and enriching the workflow with different contributes. The real weight of these afferents on patient’s management remains to be assessed and characterized. The main topics will be related to innovative CT applications able to improve patient management and treatment assessment and reduce patients risks due to radiation exposure and iodinated contrast injection.

Does Contrast Dose Based in Lean body Weight Allow Lesser Volumes on High BMI Patients for CT Angiography?

Objectives: The objective was to evaluate whether contrast dose based on lean body weight (LBW) protocol has the potential to reduce contrast volume in patients with high basal metabolic index (BMI) compared to total body weight (TBW)-based protocols. Material and Methods: The Institutional Review Board approval was obtained for this prospective study. Initially, a pilot study with a sample size of 150 patients was conducted to estimate the average fat fraction in our population. Then, CT angiography (CTA) for the thoracic and abdominal aorta was performed using a 256-multidetector computed tomography scanner in 117 patients who were undergoing screening for aortic aneurysm and vascular assessment of prospective transplant donors. The patients were divided into two groups: A TBW group (n = 60) and LBW group (n = 57). Lean body weight (LBW) was estimated from the patient weight, height, and gender using Hume’s equation. The TBW group received 1.2 ml/kg contrast dose and the LBW group received 1.6 ml/kg contrast dose to achieve approximately equal iodine dose in both groups. Differences in the degree of aortic enhancement between the estimated LBW and TBW group were evaluated. In higher BMI patients (>25), the mean aortic enhancement (MAEnh) and the contrast volume delivered between the LBW and TBW group were compared. Results: Mean aortic enhancement (MAEnh) 422.45 (±74.5) Hounsfield unit (HU) in the TBW group and 432.67 (±69.4) HU in the LBW group showed no statistical difference (P = 0.439). In population with BMI >25, the contrast delivered in LBW protocol patients was significantly less (P = 0.00) compared to TBW protocol patients, with no significant difference in the MAEnh between the groups (P = 0.479). Conclusion: CTA using a LBW protocol helps to significantly reduce the volume of contrast delivered, especially in patients with BMI >25 compared to TBW protocol, without compromising the aortic enhancement.

Application of 70 kVp in abdominal CT angiography to reduce both radiation and contrast dosage and improve patient comfort for children

BACKGROUND: Low-tube voltage scanning improves CT attenuation value of contrast medium (CM). Thus, we hypothesized that 70 kVp in pediatric abdominal CT angiography (CTA) could be used to reduce both radiation and CM dose and improve patient comfort at the same time. OBJECTIVE: To evaluate the feasibility of using 70 kVp in pediatric abdominal CTA to reduce radiation dose and CM dose and improve patient care for children. MATERIALS AND METHODS: Forty-six children needing abdominal CTA were enrolled in the study group using low-dose scanning protocol with 70 kVp and 0.7–1.1 ml/kg contrast dose, and reconstructed with 50%ASIR-V. They were compared with other 46 children in control group with matching body weight and underwent conventional CT scans with 100 kVp, 1.2–1.8 ml/kg contrast dose and reconstructed using 50%ASIR. Image quality of large vessels was evaluated using a 5-point scale. CT value and standard deviation of descending aorta (Ao) was measured, and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Radiation dose, contrast dose, the maximum injection pressure between the two groups were also compared. RESULTS: Score for displaying large vessels by 70 kVp images was 3.91±0.28, lower than that (4.17±0.38) of the control group (p < 0.05), but fully met the diagnostic requirements. CT value of Ao was 390.87±86.79HU in study group, which is higher than 343.93±49.94HU in control group, while there was no difference in SNR and CNR between two groups; the radiation dose, contrast dosage and injection pressure of the study group were 1.23±0.39mGy, 12.67±7.27 ml and 43.83±17.16psi, respectively, which are significantly lower than the 1.95±0.37mGy, 22.67±7.39 ml, and 77.59±19.68psi of control group. CONCLUSION: Use of 70 kVp in pediatric abdominal CTA provides diagnostic quality images while significantly reduce radiation and contrast dose, as well as injection pressure to improve patient comfort for children.

MO415DOES LOW CONTRAST VOLUMES REDUCE RATES OF CONTRAST-INDUCED NEPHROPATHY IN PATIENTS UNDERGOING CORONARY ANGIOGRAPHY?

Background and Aims Coronary angiography (CAG) necessitates administration of iodinated contrast, which may precipitate an acute deterioration in renal function (contrast-induced nephropathy). Previous work on contrast-induced nephropathy (CIN) has identified contrast volume as a risk factor and suggested that there is a toxic contrast dose above which the risk of CIN is markedly increased. The focus of this study is to provide a critical appraisal of this modifiable risk factor. Method We prospectively enrolled 158 patients who CAG with or without percutaneous coronary intervention from December 2017 to February 2018 at a cardiology department . CIN was defined as an increase in serum creatinine level &gt;25% or 0.5 mg/dL after 48 hours postcardiac catheterization. Toxic contrast dose was defined as a ratio volume of contrast media to estimated glomerular filtration rate (V/eGFR) &gt; 2 . Multivariable regression was conducted to evaluate the effect of exceeding the toxic contrast dose on CIN. Results Of 158 patients (females = 36.1%, mean age 60.0 ± 11 years) who underwent CAG , 15 (9,5%) developed CIN . The volume administered of contrast was not related to the existence of postprocedure CIN (96,6±35,9 ml vs 102,5±33,7ml , p=0,16). However , it was associated with a higher incidence of CIN in patients with chronic renal failure (90±19,1 ml vs 116,6±73,7ml , p=0,008) . The mean V/eGFR value was 1,2±0,7.Nine percent of patients exceeded the toxic contrast dose. After adjusting for other known predictors of CIN, a V/eGFR ratio &gt; 2 remained significantly associated with CIN (odds ratio 4.7, 95% confidence interval 1.28-17.7, P=0,02). Conclusion Low incidences of CIN suggest that a reduced dose of contrast agent is safe in high-risk patients with impaired renal function. A ratio volume of contrast media to estimated glomerular filtration rate &gt; 2 is a significant and independent predictor of CIN after CAG.

Revising the Maximal Contrast Dose for Predicting Acute Kidney Injury following Coronary Intervention

<b><i>Introduction:</i></b> The maximal allowable contrast dose (MACD = 5 × body weight/serum creatinine) is an empiric equation that has been used and validated in several studies to mitigate the risk of contrast-induced acute kidney injury (CI-AKI). However, coefficient 5 (referred to as factor <i>K</i>) was empirically devised and never disputed. The aim of this study was to refine the MACD equation for the prediction of CI-AKI following percutaneous coronary interventions (PCIs). <b><i>Methods:</i></b> This is a single-center, retrospective cohort study of adults undergoing PCI. Electronic medical records were reviewed to identify patients who underwent PCI between 2010 and 2019, derived from the National Cardiovascular Data Registry Cath-PCI registry for our hospital. Factor <i>K</i> (defined as contrast volume × serum creatinine/body weight) was calculated for every patient. A receiver operating characteristic (ROC) curve was constructed, and the Youden index was used to identify the optimal cut-off value for factor <i>K</i> in predicting severe (stages 2–3) CI-AKI. <b><i>Results:</i></b> Of the 3,506 patients undergoing PCI, 255 (7.2%) developed CI-AKI, and 68 (26.7%) of the 255 experienced severe AKI. Factor <i>K</i> predicted all-stage CI-AKI (area under the ROC curve 0.649; 95% CI 0.611, 0.686) but had better performance for predicting severe (stages 2–3) AKI (0.736; 95% CI 0.674, 0.800). The optimal cut-off value for factor <i>K</i> in predicting severe CI-AKI was 2.5, with a corresponding sensitivity of 68.7% and specificity of 70.5%. On subgroup analyses, optimal cut-off values for factor <i>K</i> for high-risk groups were not significantly different from those of low-risk groups. <b><i>Conclusion:</i></b> Our study indicates that factor <i>K</i> in the MACD equation is an independent risk factor for the development of severe CI-AKI, with an optimal cut-off value of 2.5. If our findings are validated, the MACD equation should be revised to incorporate the coefficient of 2.5 instead of 5.

Relation of contrast volume to new onset atrial fibrillation in acute coronary syndrome underwent percutaneous coronary intervention

Introduction There is an important relationship between atrial fibrillation (AF) and contrast induced nephropathy (CIN). Several hypotheses were suggested to explain this unidirectional association between CIN and AF, like influence on renin-angiotensin-aldosterone system and the inflammatory pathway, as well as the use of iodinated contrasts -due to its possible interaction at the thyroid hormone regulation-. Purpose The aim of this study was to analyze the relation between contrast volume and the subsequent development of AF in patients with acute coronary syndrome (ACS) Methods A total of 6,133 ACS patients underwent PCI between 2010 and 2016 were analyzed. We have excluded 1,896 patients with prior history of AF, without data about contrast volume or with missing data about follow-up. The impact of contrast volume in the development of AF was assessed by Cox regression analysis. Hazard Ratios (HR) with 95% of confidence interval (CI) were reported. Maximum allowable contrast dose (MACD) was defined as 5*body weight/serum creatinine. Results From the total study population (4,237 patients, 64.3±12.8 years, 24.2% women), 399 (9.4%) developed AF during a mean follow-up of 3.5±2.4 years. Mean contrast volume used was 199.9±90.3 ml. Contrast volume was not associated with follow-up de novo AF (HR 0.99, 95% CI: 0.99–1.00; p=0.834). However, the ratio between contrast volume used and the maximum allowable contrast dose (CV/MACD) resulted a predictor of follow-up AF (HR 1.18, 95% CI: 1.02–1.37, p=0.027). The cumulative incidence of AF was 2.7 per 100 patients/year in patients with CV/MACD ≤1 and 4.8 per 100 patients/year in patients with CV/MACD &gt;1. After adjusting for those variables associated with follow-up AF in the univariate analysis, the use of a contrast volume higher than MACD resulted an independent predictor of AF (HR 1.40, 95% CI: 1.03–1.89; p=0.032). Conclusion Doses of contrast volume higher than the maximum allowable contrast dose were independently associated with higher rates of AF during the follow-up. Cumulative incidence of AF by groups Funding Acknowledgement Type of funding source: None