Implantation of the coronary sinus reducer for refractory angina due to coronary microvascular dysfunction in the context of apical hypertrophic cardiomyopathy-a case report

Background: Refractory angina leads to a poor quality of life and increased healthcare resource utilization. In this growing population of patients, multiple mechanism(s) of ischaemia may co-exist, including functional disorders of the coronary microcirculation. There are few evidence-based effective therapies resulting in a large unmet clinical need. Case summary: A 38-year-old woman with refractory angina was referred with daily chest pain despite multiple anti-anginal medications and previous percutaneous coronary intervention. Cardiac magnetic resonance imaging demonstrated apical hypertrophic cardiomyopathy (HCM). Rubidium-82 positron emission tomography (PET) with regadenoson stress confirmed significant myocardial ischaemia in the apex and apical regions (16% of total myocardium) with a global myocardial perfusion reserve (MPR) of 1.23. Coronary angiography confirmed patent stents and no epicardial coronary artery disease. Therefore, the mechanism of ischaemia was thought attributable to coronary microvascular dysfunction (CMD) in the context of HCM. In view of her significant symptoms and large burden of left-sided myocardial ischaemia, a Coronary Sinus Reducer (CSR) was implanted. Repeat PET imaging at 6 months showed a marked reduction in ischaemia (<5% burden), improvement in global MPR (1.58), symptoms, and quality of life. Conclusion: In refractory angina, ischaemia may be due to disorders of both the epicardial and coronary microcirculations. The CSR is a potential therapy for these patients, but its mechanism of action has not been confirmed. This report suggests that CSR implantation may reduce myocardial ischaemia and improve symptoms by acting on the coronary microcirculation. The efficacy of CSR in patients with CMD and its mechanism of action on the coronary microcirculation warrant further investigation

Quantitative magnetization transfer imaging as a biomarker for effects of systemic inflammation on the brain

BACKGROUND Systemic inflammation impairs brain function and is increasingly implicated in the etiology of common mental illnesses, particularly depression and Alzheimer's disease. Immunotherapies selectively targeting proinflammatory cytokines demonstrate efficacy in a subset of patients with depression. However, efforts to identify patients most vulnerable to the central effects of inflammation are hindered by insensitivity of conventional structural magnetic resonance imaging. METHODS We used quantitative magnetization transfer (qMT) imaging, a magnetic resonance imaging technique that enables quantification of changes in brain macromolecular density, together with experimentally induced inflammation to investigate effects of systemic inflammatory challenge on human brain microstructure. Imaging with qMT was performed in 20 healthy participants after typhoid vaccination and saline control injection. An additional 20 participants underwent fluorodeoxyglucose positron emission tomography following the same inflammatory challenge. RESULTS The qMT data demonstrated that inflammation induced a rapid change in brain microstructure, reflected in increased magnetization exchange from free (water) to macromolecular-bound protons, within a discrete region of insular cortex implicated in representing internal physiologic states including inflammation. The functional significance of this change in insular microstructure was demonstrated by correlation with inflammation-induced fatigue and fluorodeoxyglucose positron emission tomography imaging, which revealed increased resting glucose metabolism within this region following the same inflammatory challenge. CONCLUSIONS Together these observations highlight a novel structural biomarker of the central physiologic and behavioral effects of mild systemic inflammation. The widespread clinical availability of magnetic resonance imaging supports the viability of qMT imaging as a clinical biomarker in trials of immunotherapeutics, both to identify patients vulnerable to the effects of systemic inflammation and to monitor neurobiological responses

Effect of blood glucose level on standardized uptake value (SUV) in F-18- FDG PET-scan : a systematic review and meta-analysis of 20,807 individual SUV measurements

Objectives To evaluate the effect of pre-scan blood glucose levels (BGL) on standardized uptake value (SUV) in F-18-FDG-PET scan. Methods A literature review was performed in the MEDLINE, Embase, and Cochrane library databases. Multivariate regression analysis was performed on individual datum to investigate the correlation of BGL with SUVmax and SUVmean adjusting for sex, age, body mass index (BMI), diabetes mellitus diagnosis, F-18-FDG injected dose, and time interval. The ANOVA test was done to evaluate differences in SUVmax or SUVmean among five different BGL groups (200 mg/dl). Results Individual data for a total of 20,807 SUVmax and SUVmean measurements from 29 studies with 8380 patients was included in the analysis. Increased BGL is significantly correlated with decreased SUVmax and SUVmean in brain (p <0.001, p <0.001,) and muscle (p <0.001, p <0.001) and increased SUVmax and SUVmean in liver (p = 0.001, p = 0004) and blood pool (p=0.008, p200 mg/dl had significantly lower SUVmax. Conclusion If BGL is lower than 200mg/dl no interventions are needed for lowering BGL, unless the liver is the organ of interest. Future studies are needed to evaluate sensitivity and specificity of FDG-PET scan in diagnosis of malignant lesions in hyperglycemia.Peer reviewe

Fasting hepatic glucose uptake is higher in men than women

Differences in glucose metabolism between men and women have previously been reported. Our purpose was to determine if there is a gender difference in fasting hepatic glucose uptake (MRglu). Fifty‐five patients (44 men, 11 women) referred for routine PET/CT using the glucose tracer 2‐deoxy‐2‐[F‐18]fluoro‐D‐glucose (FDG), mainly for cancer, had dynamic imaging for 30 min immediately following injection. Hepatic FDG clearance (mL/min/100 mL) was measured as gradient divided by intercept from Patlak–Rutland graphical analysis using a volume of interest over the abdominal aorta to record input function. Hepatic MRglu was obtained by multiplication of clearance by blood glucose concentration. Hepatic steatosis was diagnosed as CT density ≤40 HU. Mean (standard deviation) hepatic MRglu in 44 men was 2.30 (1.14) μmol/min/100 mL, significantly higher than in 11 women in whom it was 1.07 (1.35) μmol/min/100 mL (P = 0.003). CT density was 52 (12) HU in women compared with 45 (9) HU in men (P = 0.04), but there was no significant difference in blood glucose, BMI, or prevalence of recent chemotherapy (within 6 months preceding PET/CT). When patients were subdivided into those without hepatic steatosis (31 men/9 women), those without evidence of FDG‐avid malignancy on PET/CT (15/6), and those without either (11/5), gender differences in hepatic MRglu remained highly significant, but there were no significant differences in CT density, blood glucose, BMI, or recent chemotherapy history. Despite this being a population of clinically referred patients, the results strongly suggest that fasting hepatic MRglu is higher in men than in women

Right ventricular involvement in hypertrophic cardiomyopathy: Patterns and implications

Although hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy worldwide, the criteria for its definition and most of the literature concern the left ventricle, thus confirming the theory that the right ventricle is the neglected one. Right ventricular (RV) involvement includes structural and functional changes with significant impact on clinical presentation and prognosis. The pattern of RV hypertrophy can be variable with possible dynamic obstruction. Histological findings suggest similar pathogenetic changes in both ventricles supporting the common myopathic process with sarcomeric mutations. Systolic dysfunction of the RV is subtle, and the classical echocardiographic indices are usually within normal limits, while global longitudinal strain is significantly impaired. Diastolic dysfunction of the RV is also evident in patients with HCM possibly due to fibrosis of the RV free wall and/or the obstruction of the RV filling with significant prognostic implications. RV involvement in HCM is associated with increased incidence of supraventricular and ventricular arrhythmias, severe dyspnea, pulmonary thromboembolism, progressive heart failure, and increased risk of sudden cardiac death. Therefore, the RV should be routinely included in the detailed assessment of patients with HCM. © 2018 Hellenic Society of Cardiolog

Buck-Boost Charge Pump based DC-DC converter

A dual mode buck-boost charge pump is presented in this paper. The two modes, buck and boost, of the CP can be used by the same circuit for degrading or elevating the output voltage, respectively, compared to the input. Each mode can be achieved by switching only the input-output connections without any other change in the design of the DC-DC converter. This dual mode configuration aims to merge two different functions into one circuit minimizing the area the DC-DC converter occupies on the die. The proposed buck-boost CP has been designed using TSMC 130nm complementary metal-oxide-semiconductor (CMOS) technology providing a 3.3V output voltage from a 2.2V supply voltage when the DC-DC converter operates in boost mode and a 1.6V output voltage from a 3.3V supply voltage in buck mode. A 2uF capacitor has been placed at the output of the CP. For the buck mode, the capacitor of the output must be pre-charged in order for the CP to operate properly. © 2022 IEEE

Temperature compensated ring oscillator based VCO

Frequency drift due to temperature variations is a crucial design consideration and cannot always be compensated by a phase-locked loop especially when low-gain, multiband oscillators are employed. A ring oscillator architecture with reduced frequency drift over temperature is presented in this paper. The oscillator is incorporated in a phase locked loop (PLL) to produce a stable clock within the required frequency range under process, voltage, and temperature variations. The output frequency of the oscillator is compensated through a proportional to absolute temperature (PTAT) current in order to eliminate the frequency drift. A proof-of-concept PLL has been designed and fabricated in a 180 nm CMOS technology operating with 3.3 V supply voltage and providing a 480 MHz frequency. Measurement results of the fabricated chip show a frequency variation of the VCO from −1.5 % to + 0.4 % from the center frequency across the temperature range from −40 °C to 120 °C meeting the requirements for most consumer market applications. The duty cycle distortion is less than 1% across the temperature range. The phase noise of the oscillator was measured at −107 dBc/Hz. © 2022 Elsevier Gmb