Arterial wave reflection during antihypertensive therapy with barnidipine: a 6-month, open-label study using an integrated cardiovascular ultrasound approach in patients with newly diagnosed hypertension.

BACKGROUND: Increased central aortic pressure resulting from large artery stiffening and increased wave reflection is associated with higher hypertension-related morbidity. OBJECTIVE: The goal of this study was to evaluate the effects of a vasodilator-based therapy with the calcium channel blocker barnidipine on arterial stiffness, wave reflection, and left ventricular (LV) performance using an integrated cardiovascular ultrasound approach (including wave intensity analysis). METHODS: Newly diagnosed, previously untreated patients with grade 1 or 2 essential hypertension (systolic blood pressure [BP] > or =140 and <180 mm Hg, and/or diastolic BP > or =90 and <110 mm Hg), and with no signs of clinical cardiovascular disease, were eligible for study. Carotid artery mechanics were investigated at baseline and after 3 and 6 months of barnidipine therapy (10-20 mg once daily, according to an open-label design) using a double-beam carotid ultrasound technique. This provided a simultaneous recording of diameter-derived pressure and flow velocity signals and allowed analysis of wave intensity. Indices of local arterial stiffness and wave reflection, as well as separated forward and backward pressure waves, were estimated. LV geometry, mass, and systolic and diastolic performance were also assessed using Doppler echocardiography. All ultrasound examinations and readings were performed by investigators blinded to patient demographics and treatment phase. Normotensive control subjects (office BP <140/90 mm Hg) were included as a reference group. RESULTS: Twenty-one white, treatment-naive patients with hypertension (mean [SD] age, 58 [8] years; 14 males; mean body mass index, 27 [5] kg/m(2); mean BP, 159 [14]/96 [5] mm Hg) were enrolled. Twenty normotensive subjects comprised the control group. Compared with the control subjects, patients with hypertension had a higher mean augmentation index ([AIx] 22.0% [7.0%] vs 13.1% [5.2%]; P < 0.01), Peterson's pressure-strain elastic modulus (175 [49] vs 126 [41] kPa; P < 0.01), and forward and backward pressure waves (137 [17] vs 108 [7] mm Hg [P < 0.001] and 21 [6] vs 17 [5] mm Hg [P < 0.05], respectively) at baseline. After 6 months of barnidipine treatment, mean office BP in the patients with hypertension decreased from 159 (14)/96 (5) mm Hg at baseline to 138 (16)/81 (9) mm Hg (P < 0.001) due to a significant reduction in forward and backward pressure waves, and AIx decreased to 17.0% (8.0%) (P < 0.01); there were no significant changes in indices of intrinsic arterial stiffness. A significant direct relationship between AIx and pulse pressure (r = 0.45 [P < 0.05]) was observed at baseline in hypertensive patients but not after therapy (r = 0.26 [P = NS]). Mean stress-adjusted LV midwall shortening increased from 110% (17%) at baseline to 118% (13%) at 6 months (P < 0.05), which was comparable to baseline values in the control subjects (119% [10%]). CONCLUSION: In these middle-aged patients with newly diagnosed mild to moderate hypertension, vasodilator therapy with barnidipine reduced central BP by a parallel reduction of forward and backward pressure waves, together with a later arrival of the reflected waves, with no significant changes in intrinsic arterial stiffness.

Data integration in eHealth: a domain/disease specific roadmap.

The paper documents a series of data integration workshops held in 2006 at the UK National e-Science Centre, summarizing a range of the problem/solution scenarios in multi-site and multi-scale data integration with six HealthGrid projects using schizophrenia as a domain-specific test case. It outlines emerging strategies, recommendations and objectives for collaboration on shared ontology-building and harmonization of data for multi-site trials in this domain.

The construction of a model eye for investigation of laser-tissue interactions in scanning laser ophthalmoscopy.

PURPOSE: To develop a model eye to study laser-tissue interactions during retinal imaging with scanning ophthalmoscopy. METHODS: A model eye was designed to match the optical properties of the human eye based on the Bennett and Rabbetts schematic eye. RESULTS: Alterations in axial length resulted in changes in refractive error similar to those in the human eye (3.70 D for 1 mm in axial length). Perfusion-fixed retinal tissue could be successfully imaged using the Heidelberg Retina Tomograph and Optical Coherence Tomograph to provide images that are similar in quality to those obtained. CONCLUSIONS: The model eye should be a valuable tool for investigating laser-tissue interactions during scanning laser ophthalmoscopy and the derivation of digital retinal and tomographic images. This model should also enable a determination of the accuracy with which digital imaging techniques, such as the optical coherence tomograph and Heidelberg Retina Tomograph, measure retinal structure.