ESH position paper: renal denervation - an interventional therapy of resistant hypertension

Experts from the European Society of Hypertension prepared this position paper in order to summarize current evidence, unmet needs and practical recommendations on the application of percutaneous transluminal ablation of renal nerves [renal denervation (RDN)] as a novel therapeutic strategy for the treatment of resistant hypertension. The sympathetic nervous activation to the kidney and the sensory afferent signals to the central nervous system represent the targets of RND. Clinical studies have documented that catheter-based RDN decreases both efferent sympathetic and afferent sensory nerve traffic leading to clinically meaningful systolic and diastolic blood pressure (BP) reductions in patients with resistant hypertension. This position statement intends to facilitate a better understanding of the effectiveness, safety, limitations and issues still to be addressed with RDN.     

Association of pulse pressure with new-onset atrial fibrillation in patients with hypertension and left ventricular hypertrophy: the Losartan Intervention For Endpoint (LIFE) reduction in hypertension study

Previous studies have found pulse pressure (PP), a marker of arterial stiffness, to be an independent predictor of atrial fibrillation (AF) in general and hypertensive populations. We examined whether PP predicted new-onset AF in comparison with other blood pressure components in the Losartan Intervention For Endpoint reduction in hypertension study, a double-blind, randomized (losartan versus atenolol), parallel-group study, including 9193 patients with hypertension and electrocardiographic left ventricular hypertrophy. In 8810 patients with neither a history of AF nor AF at baseline, Minnesota coding of electrocardiograms confirmed new-onset AF in 353 patients (4.0%) during mean 4.9 years of follow-up. In multivariate Cox regression analyses, baseline and in-treatment PP and baseline and in-treatment systolic blood pressure predicted new-onset AF, independent of baseline age, height, weight, and Framingham Risk Score; sex, race, and treatment allocation; and in-treatment heart rate and Cornell product. PP was the strongest single blood pressure predictor of new-onset AF determined by the decrease in the -2 Log likelihood statistic, in comparison with systolic blood pressure, diastolic blood pressure, and mean arterial pressure. When evaluated in the same model, the predictive effect of systolic and diastolic blood pressures together was similar to that of PP. In this population of patients with hypertension and left ventricular hypertrophy, PP was the strongest single blood pressure predictor of new-onset AF, independent of other risk factors.     

Impact of sampling rate for time domain analysis of continuous intracranial pressure (ICP) signals

Time domain analysis of the intracranial pressure (ICP) waveform is critically dependent on the exact reproduction of the ICP waveform. This study explored how the sampling rate of the ICP signal affects the time domain analysis. It was also assessed through this study how upsampling (interpolation) improves the time domain analysis. From the hospital database, a set of 55 ICP waveforms were retrieved from 48 patients (28 children and 20 adults). First, the ICP signals originally sampled at 200 or 100 Hz were compared with the ICP signals downsampled to 5, 10, 20, 25, 50 Hz (and 100 Hz). Second, the original ICP signals were compared with ICP signals upsampled (i.e. interpolated) to 100 Hz (from 5, 10, 20, 25 or 50 Hz). For each ICP recording the output of time domain analysis was the average value and the quantitative distribution of mean ICP wave amplitudes determined every six second (6 s) time window. The total material incorporated a total of 373,371 6 s time windows. Downsampling revealed that the time domain analysis could be most faithfully applied to ICP signals sampled at 50 Hz or above, while ICP signals sampled at 25 Hz deviated more from the original signal than we would accept from a clinical perspective. The use of interpolation gave better representation of the peaks, and should be applied to all ICP signals sampled at lower rate than 100 Hz.