Cognitive decline in thrombotic thrombocytopenic purpura survivors: The role of white matter health as assessed by MRI.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare condition caused by severe ADAMTS13 deficiency, leading to platelet aggregation and thrombosis. Despite treatment, patients are prone to cognitive impairment and depression. We investigated brain changes in iTTP patients during remission using advanced magnetic resonance imaging (MRI) techniques, correlating these changes with mood and neurocognitive tests. Twenty iTTP patients in remission (30 days post-haematological remission) were compared with six healthy controls. MRI scans, including standard and specialized sequences, were conducted to assess white matter health. Increased T1 relaxation times were found in the cingulate cortex (p < 0.05), and elevated T2 relaxation times were observed in the cingulate cortex, frontal, parietal and temporal lobes (p < 0.05). Pathological changes in these areas are correlated with impaired cognitive and depressive scores in concentration, short-term memory and verbal memory. This study highlights persistent white matter damage in iTTP patients, potentially contributing to depression and cognitive impairment. Key regions affected include the frontal lobe and cingulate cortex. These findings have significant implications for the acute and long-term management of iTTP, suggesting a need for re-evaluation of treatment approaches during both active phases and remission. Further research is warranted to enhance our understanding of these complexities.

ECG machine QTc intervals are inaccurate in hemodialysis patients.

BACKGROUND: Nephrologists need effective screening tools to identify hemodialysis patients at elevated risk for sudden cardiac death, the leading cause of death in this population. QTc intervals longer than 450 ms in males and 470 ms in females, measured by the gold standard tangent method (trueQTc), are prolonged and increase sudden cardiac death in healthy populations and patients with long QT syndrome. METHODS: We performed a retrospective ECG and chart review of hemodialysis patients. Our first objective was to determine if machine-measured QTc intervals (macQTc) could be used to identify dialysis patients with prolonged trueQTc. Our second objective was to determine at what macQTc could prolonged trueQTc be confidently diagnosed. RESULTS: macQTc differed from the trueQTc by an average of 16.54 ms, and by at least 20 ms in 46.8, 36.1, 53.6, 50.0 and 57.1% of all, short-hours daily hemodialysis, intermittent conventional hemodialysis, frequent nocturnal hemodialysis and intermittent nocturnal hemodialysis patients, respectively. The positive predictive value, negative predictive value, sensitivity and specificity of prolonged macQTc predicting prolonged trueQTc was 57.6, 92.6, 79.1 and 81.8%, respectively. Thus, macQTc is inaccurate at predicting the gold standard trueQTc in hemodialysis patients. macQTc greater than 480 ms in hemodialysis patients predicts trueQTc prolongation with a positive predictive value of 95.2%, but with a low sensitivity of 32.3%. CONCLUSION: In hemodialysis patients, ECG macQTc intervals are insufficiently sensitive or specific to predict prolonged trueQTc intervals, unless >480 ms.