H igh blood pressure (BP) affects ≈25% of the world's population and is the largest single contributor to global mortality. 1 Hypertension represents a significant economic burden to public healthcare providers, where the global cost of nonoptimal BP is estimated to be US$370 billion (10% of healthcare expenditure). 2Remarkably, despite the availability of many pharmacological treatments, BP is poorly controlled with a recent report stating that only 53% of patients prescribed antihypertensive medication have BP controlled.3 This reflects the well-known heterogeneity of the syndrome, including epigenetic and inherited factors contributing to the unknown causes in 95% of patients. Despite the devastating consequences of hypertension (eg, stroke, kidney failure, coronary heart disease, and death 1,2 ), the mechanisms that lead to the onset of hypertension in humans are poorly understood. It is well established that elevated sympathetic nerve activity (SNA) contributes to the development of hypertension in most humans, [5][6][7] but what initiates this remains unclear. Experimental data from hypertensive rats and observations in postmortem human studies suggest that blood flow to the brain might be important in setting the operating level of SNA and, thus, systemic arterial pressure. Rationale: Data from animal models of hypertension indicate that high blood pressure may develop as a vital mechanism to maintain adequate blood flow to the brain. We propose that congenital vascular variants of the posterior cerebral circulation and cerebral hypoperfusion could partially explain the pathogenesis of essential hypertension, which remains enigmatic in 95% of patients.Objective: To evaluate the role of the cerebral circulation in the pathophysiology of hypertension. Methods and Results:We completed a series of retrospective and mechanistic case-control magnetic resonance imaging and physiological studies in normotensive and hypertensive humans (n=259). Interestingly, in humans with hypertension, we report a higher prevalence of congenital cerebrovascular variants; vertebral artery hypoplasia, and an incomplete posterior circle of Willis, which were coupled with increased cerebral vascular resistance, reduced cerebral blood flow, and a higher incidence of lacunar type infarcts. Causally, cerebral vascular resistance was elevated before the onset of hypertension and elevated sympathetic nerve activity (n=126). Interestingly, untreated hypertensive patients (n=20) had a cerebral blood flow similar to age-matched controls (n=28). However, participants receiving antihypertensive therapy (with blood pressure controlled below target levels) had reduced cerebral perfusion (n=19). Finally, elevated cerebral vascular resistance was a predictor of hypertension, suggesting that it may be a novel prognostic or diagnostic marker (n=126). Conclusions:
Background Falls are a common complication of Parkinson’s disease. There is a need for new therapeutic options to target this debilitating aspect of the disease. Cholinergic deficit has been shown to contribute to both gait and cognitive dysfunction seen in the condition. Potential benefits of using cholinesterase inhibitors were shown during a single centre phase 2 trial. The aim of this trial is to evaluate the effectiveness of a cholinesterase inhibitor on fall rate in people with idiopathic Parkinson’s disease. Methods This is a multi-centre, double-blind, randomised placebo-controlled trial in 600 people with idiopathic Parkinson’s disease (Hoehn and Yahr stages 1 to 4) with a history of a fall in the past year. Participants will be randomised to two groups, receiving either transdermal rivastigmine or identical placebo for 12 months. The primary outcome is the fall rate over 12 months follow-up. Secondary outcome measures, collected at baseline and 12 months either face-to-face or via remote video/telephone assessments, include gait and balance measures, neuropsychiatric indices, Parkinson’s motor and non-motor symptoms, quality of life and cost-effectiveness. Discussion This trial will establish whether cholinesterase inhibitor therapy is effective in preventing falls in Parkinson’s disease. If cost-effective, it will alter current management guidelines by offering a new therapeutic option in this high-risk population. Trial registration REC reference: 19/SW/0043. EudraCT: 2018–003219-23. ISCRTN: 41639809 (registered 16/04/2019). ClinicalTrials.gov Identifier: NCT04226248 Protocol at time of publication Version 7.0, 20th January 2021.
Spiral-CT is a fast, safe and almost always available method for detection of pulmonary embolism. In our hands it is superior to v/p-scintigraphy. It allows direct detection of a thrombus and has additional advantages in differential diagnosis (e. g. lung carcinoma, infectious infiltration). In patients with clinical suspicion of pulmonary embolism spiral-CT should be the primary diagnostic modality.
Transduction of muscle sympathetic nerve activity (MSNA) into vascular tone varies with age and sex. Older normotensive men have reduced sympathetic transduction so that a given level of MSNA causes less arteriole vasoconstriction. Whether sympathetic transduction is altered in hypertension (HTN) is not known. We investigated whether sympathetic transduction is impaired in untreated hypertensive men compared to normotensive controls. Eight untreated hypertensive men and 10 normotensive men (age 50 ± 15 years vs. 45 ± 12 years (mean ± SD); p = 0.19, body mass index (BMI) 24.7 ± 2.7 kg/m2 vs. 26.0 ± 4.2 kg/m2; p = 0.21) were recruited. MSNA was recorded from the peroneal nerve using microneurography; beat-to-beat blood pressure (BP; Finapres) and heart rate (ECG) were recorded simultaneously at rest for 10 min. Sympathetic-transduction was quantified using a previously described method. The relationship between MSNA burst area and subsequent diastolic BP was measured for each participant with the slope of the regression indicating sympathetic transduction. MSNA was higher in the hypertensive group compared to normotensives (73 ± 17 bursts/100 heartbeats vs. 49 ± 19 bursts/100 heart bursts; p = 0.007). Sympathetic-transduction was lower in the hypertensive versus normotensive group (0.04%/mmHg/s vs. 0.11%/mmHg/s, respectively; R = 0.622; p = 0.006). In summary, hypertensive men had lower sympathetic transduction compared to normotensive individuals suggesting that higher levels of MSNA are needed to cause the same level of vasoconstrictor tone.
This study shows it is feasible to study wave dynamics in the ICA non-invasively. Whilst changes in aortic wave speed confirmed an expected increase in arterial stiffness, this was not observed in the ICA. This might suggest a protective mechanism in the cerebral circulation, in conjunction with the effect of vessel tortuosity. Furthermore, it was observed that ICA shape correlated with wave energy but not wave speed.
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