Nonlinear relationship between HbA1c and coronary artery calcium score progression: a secondary analysis based on a retrospective cohort study

OBJECTIVE

Coronary artery calcium score and glycated hemoglobin(HbA1c) are both considered risk factors for coronary heart disease. However, the relationship between coronary artery calcium score and HbA1c is still unclear. Consequently, the present study was undertaken to explore HbA1c association with coronary artery calcium score progression in South Korea.

METHODS

This study is a secondary analysis based on a retrospective cohort study in which 8151 participants received Health examination kits at the Health Promotion Center, Samsung Medical Center in Seoul, South Korea, from March 1, 2003-December 31, 2013. Cox proportional-hazards regression model was then used to evaluate the independent relationship between HbA1c and coronary artery calcium score progression.

RESULTS

After adjusting potential confounding factors (age, sex, BMI, height, weight, SBP, DBP, TC, LDL-C, HDL-C, triglycerides, smoking status, alcohol consumption, reflux esophagitis status, hypertension, diabetes, dyslipidemia, ischemic heart disease and cerebrovascular disease), it was revealed that there was a nonlinear relationship between HbA1c and coronary artery calcium score progression, while the scoring point was 5.8%. The effect size was 2.06 to the left of the inflection point, while the 95% CI was 1.85 to 2.29. Whereas, the effect size was 1.04, on the right side of the inflection point while 95% CI was 0.99 to1.10.

CONCLUSION

The relationship between HbA1c and coronary artery calcium score progression is nonlinear. HbA1c is positively related to coronary artery calcium score progression when HbA1c level was less than 5.8%.

Cerebrovascular disease in pregnancy and puerperium: perspectives from neuroradiologists

Pregnancy-related cerebrovascular disease is a serious complication of pregnancy and puerperium. The etiology and pathological mechanisms of cerebrovascular disease are complex, involving changes in the cardiovascular, endocrine, and immune systems. Vascular risk factors during pregnancy and puerperium may cause vasospasm and endothelial cell damage leading to cerebral ischemia, hemorrhage, posterior reversible encephalopathy syndrome (PRES), and reversible cerebral vasoconstriction syndrome. Arterial or venous obstruction may damage the blood-brain barrier (BBB) and impede venous return, resulting in cerebral edema, hemorrhage, and intracranial hypertension. Pregnancy with hypercoagulability may threaten the lives of both the mother and the developing fetus. With improvements in stroke treatment during pregnancy and puerperium, neuroradiologists have gained new insights into this problem. This article reviews the pathogenesis, imaging findings, and risk factors of stroke during pregnancy and puerperium, focusing on imaging diagnosis and prognostic assessment.

Blood-Brain Barrier Disruption as a Potential Target for Therapy in Posterior Reversible Encephalopathy Syndrome: Evidence From Multimodal MRI in Rats

Background: To explore blood-brain barrier disruption in hypertensive posterior reversible encephalopathy syndrome. Methods: The hypertension rat models were successfully established and scanned on 7T micro-MRI. MRI parameter maps including apparent diffusion coefficient, T1 value, and perfusion metrics such as cerebral blood volume, cerebral blood flow, mean transit time and time to peak maps, were calculated. Results: The ADC values of the experimental group were higher than those of the control group both in cortical (P < 0.01) and subcortical (P < 0.05) regions. Voxel-wise analysis of ADC maps localized vasogenic edema primarily to the posterior portion of the brain. The increase in cerebral blood volume and cerebral blood flow values were found in the cortical and subcortical regions of rats with acute hypertension. No correlation was found between perfusion metrics and mean arterial pressure. The Evans blue dye content was higher in the posterior brain region than the anterior one (P < 0.05). Conclusions: Cerebral vasogenic edema resulting from acute hypertension supports the hypothesis of posterior reversible encephalopathy syndrome as the result of blood-brain barrier disruption, which maybe the potential therapeutic target for intervention.

Imaging of cerebrovascular complications of infection

Cerebrovascular complications may occur in infectious diseases in the setting of infective endocarditis, central nervous system (CNS) infections, systemic bacteremia and sepsis. Cerebrovascular complications of infections include vasculitis, mycotic aneurysms, and thrombophlebitis. Infectious vasculitis of the CNS may cause cerebral hemorrhage, infarction or ischemia. Ruptured aneurysms may endanger the patient's life. Infectious thrombophlebitis may cause intracranial pressure to increase and lead to cerebral hemorrhage. These cerebrovascular complications are associated with a poor prognosis and often cause irreversible neurological deficits. Cerebrovascular events secondary to infection are not easily distinguishable from the more common cerebral infarct and non-infectious vasculitis. In addition, the clinical manifestations of cerebrovascular complications of infections are non-specific and highly variable. Therefore, early imaging, antibiotics, and anticoagulation may be lifesaving the patient's life and prevent disability. The main focus of this article is to review imaging analysis of the cerebrovascular complications of infections and imaging features that help differentiate them from non-infectious vascular diseases.

Risk factors for poor outcome in posterior reversible encephalopathy syndrome: systematic review and meta-analysis

Background

The roles of clinical etiology and symptoms, imaging findings and biochemical parameters in predicting the prognosis of posterior reversible encephalopathy syndrome (PRES) have not been well-characterized. We perform a meta-analysis of all published studies to assess the value of various risk factors in predicting the prognosis of PRES.

Methods

Searches of the PubMed, EMBASE, Cochrane Library, and Web of Science databases were performed to identify the eligible studies. The odds ratios (ORs) with their corresponding 95% confidence interval (CI) for related risk factors were used to calculate the pooled estimates of the outcomes.

Results

Six studies with 448 cases were included in the meta-analysis. Hemorrhage was associated with high risk for poor outcome in patients with PRES. Toxemia of pregnancy (pre-eclampsia/eclampsia) was associated with improved outcome in PRES patients. Cytotoxic edema was noted to be related to poor outcome, but did not show statistical significance. The pooled OR for hemorrhage, pre-eclampsia/eclampsia, cytotoxic edema was 4.93 (95% CI: 3.94-6.17; P<0.00001), 0.24 (95% CI: 0.15-0.40; P<0.00001) and 2.59 (95% CI: 0.84-7.99; P=0.10), respectively.

Conclusions

PRES patients with hemorrhage or cytotoxic edema are likely to have poor outcomes. Pre-eclampsia/eclampsia is associated with reduced risk of poor outcome in patients with PRES.

Nervous System Injury and Neuroimaging of Zika Virus Infection

In 2016, World Health Organization announced Zika virus infection and its neurological sequalae are a public health emergency of global scope. Preliminary studies have confirmed a relationship between Zika virus infection and certain neurological disorders, including microcephaly and Guillain–Barre syndrome (GBS). The neuroimaging features of microcephaly secondary to Zika virus infection include calcifications at the junction of gray–white matter and subcortical white matter with associated cortical abnormalities, diminution of white matter, large ventricles with or without hydrocephalus, cortical malformations, hypoplasia of cerebellum and brainstem, and enlargement of cerebellomedullary cistern. Contrast enhancement of the cauda equine nerve roots is the typical neuroimaging finding of GBS associated with Zika virus. This review describes the nervous system disorders and associated imaging findings seen in Zika virus infection, with the aim to improve the understanding of this disease. Imaging plays a key role on accurate diagnosis and prognostic evaluation of this disease.

Controversy of posterior reversible encephalopathy syndrome: what have we learnt in the last 20 years?

Over two decades have passed since posterior reversible encephalopathy syndrome (PRES) was first described in 1996. It has becoming increasingly recognised because of improved and more readily available imaging modality. The exact pathophysiological mechanism is not completely understood and remains controversial at present. Precise diagnosis is essential to guide prompt, proper management. Our ability of differentiating it from other acute neurological disorders is likely to improve as we learnt more about the spectrum of this entity in the last 20 years. We emphasise the importance of recognising its diagnostic criteria and biomarker, which would be of great relevance to either outcome evaluation or study design. PRES has a favourable prognosis generally, but neurological sequelae and even fatalities can occur, especially in severe forms that might cause substantial morbidity and even mortality, particularly when the syndrome is complicated by intracranial haemorrhage or brain infarction. In this review, the pathophysiology, approach to diagnosis, some controversies as to the prognosis, as well as the future research direction of PRES are described.