Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. e154 Journal of Hypertension Vol 35, e-Supplement 2, September 2017 Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy, 2 Chair of Ophtalmology, University of Brescia, Brescia, Italy, 3 Department of Mechanical and Industrial Engineering, University of Bres- cia, Brescia, Italy, 4 Department of Information Engineering, University of Brescia, Brescia, Italy, 5 Istituto Clinico Città di Brescia, Division of Medi- cine, Brescia, Italy Objective: The evaluation of the morphological characteristics of small resistance arteries in human beings in not easy. The gold standard is generally considered to be the evaluation of the media to lumen ratio of subcutaneous small vessels obtained by local biopsies and measured by wire or pressure micromyiography. However, non-invasive techniques for the evaluation of retinal arterioles were recently proposed, in particular two approaches seem to provide interesting in- formation: scanning laser Doppler flowmetry and adaptive optics; both of them provide an estimation of the wall to lumen ratio (WLR) of retinal arterioles. The reproducibility of such measurements was previously stated to be acceptable (co- efficient of variation < 10% for SLDF, < 4% for RTX-1), however, no direct com- parison of the two techniques in the same population was previously performed. Design and method: Therefore, we evaluated 18 subjects and patients (10 nor- motensives, 8 hypertensives, 7/18 severely obese). In all of them an evaluation of the WLR of retinal arterioles was made by Scanning Laser Doppler Flowm- etry (SLDF, Heidelberg Engineering, Heidelberg, Germany) and adaptive optics (RTX-1, Imagine Eyes, Orsay, France). The same operator evaluated the same ac- quired images in two different days (intra-observer variability), and two different operators evaluated the same images in the same day (inter-observer variability). Results: The results are reported in the Table (***p < 0.001). Variation coefficient of SLDF is much greater than that of AO. Conclusions: It is clear how the reproducibility of the evaluation of the WLR with adaptive optics is far better, as compared with SLDF, since the variation coef- ficient are clearly lower. This may be important in terms of clinical evaluation of microvascular morphology in a clinical setting. PP.09.18 CANRENONE DECREASES SYSTEMIC ARTERIAL STIFFNESS IN ESSENTIAL HYPERTENSIVES M. Rescaldani 1 , E. Gherbesi 1 , G. Bolla 1 , M. Vanasia 2 , C. Sala 1 , F. Lombardi 1 . 1 University of Milan and Fondazione IRCCS Ospedale Maggiore Policlinico, Milano, Italy, 2 Therabel GiEnne Pharma, Milano, Italy Objective: Aldosterone induces vascular fibrosis and increases arterial stiffness (AS) of conductance arteries via mineralocorticoid-receptor (MR) activation. In uncomplicated essential hypertensives (EHs) we measured systemic AS at base- line and after chronic administration of MR-antagonist Canrenone. Design and method: Twenty EHs (age 50 ± 12 yrs, M/F = 15/10, clinic BP 159/87 ± 2.4/2.2) on chronic treatment with an ACE inhibitor or angiotensin II antagonist plus hydrochlorothiazide at maximal doses, were randomly assigned to Canrenone 50 or 100 mg/day for 3 months. Blood pressure (BP, sphygmomanom- eter), heart rate (HR, EKG), stroke volume index (SVI, impedance cardiography) were measured in supine patients before and after Canrenone. AS was assessed as the ratio of pulse pressure (PP) to SVI. Results: Canrenone decreased PP (from 68.7 ± 2.9 to 51.9 ± 2.9 mmHg, means ± sem, p < 0.01) without affecting SVI (33.2 ± 1.4 vs 31.5 ± 1.4 ml/m 2 ) and HR (64.4 ± 1.9 vs 65.5 ± 2.2 bt/min). Thus, AS decreased from 2.14 ± 0.13 to 1.70 ± 0.12 mmHg/ml/m 2 (Figure), the decrements induced by low and high canrenone dose being not different (-0.49 ± 0.11 vs -0.39 ± 0.19 mmHg/ml/m 2 , respectively). Conclusions: Chronic treatment with MR-antagonist Canrenone decreases sys- temic arterial stiffness in uncomplicated EHs; this effect may improve cardiovas- cular risk profile in these subjects. PP.09.19 LONG-TERM WELL-CONTROLLED BLOOD PRESSURE LEVELS AND CAROTID ELASTICITY IN YOUNG HYPERTENSIVE SUBJECTS M. Puato 1 , M. Rattazzi 2 , R. Pesavento 1 , C. Fania 1 , P. Palatini 1 , P. Pauletto 2 . 1 Dipartimento di Medicina, Azienda Ospedaliera Universitaria di Padova, Padova, Italy, 2 Medicina Interna I, Ospedale Ca Foncello, Treviso, Italy Objective: Aim of the study was to evaluate the impact of long-term well-con- trolled blood pressure (BP) on local arterial stiffness in hypertensives. Arterial stiffness increases with age and this process can be exacerbated by the presence of cardiovascular risk factors such as hypertension. Carotid distensibility evaluation is a reliable method that could reflect the stiffness of arteries. Design and method: We studied 40 young hypertensives (mean age 49.7 years) that had been kept on pharmacological treatment and/or on lifestyle modification for at least 12 months (mean 38 months) to maintain target BP. Follow-up visit were scheduled every 6-month. Carotid compliance coefficient (CC) and disten- sibility coefficient (DC) were measured by B-mode based system coupled with dedicated software. We assessed mean carotid intima-media thickness (IMT) and maximum IMT in each carotid artery segment, bilaterally. Endothelial function was evaluated by post-occlusion flow mediated dilation (FMD). Forty normoten- sive subjects paired for age and sex served as controls. Results: In the hypertensives, BP levels were well controlled (office BP 131/79 mmHg). Compared to controls, significantly higher BP levels and BMI were present in hypertensives, whereas age and metabolic parameters were similar. Compared to normotensives, carotid elasticity was significantly impaired in hypertensives (DC 24.5 ± 8.9 vs 36.9 ± 8.5 10–3/kPa, and CC 0.92 ± 0.34 vs 1.28 ± 0.36 mm 2 /kPa). Local stiffness parameters were inversely related to age, BP, and LDL-cholesterol. Moreover, DC and CC were inversely related to IMT measurements and directly with FMD values. Conclusions: In hypertensives with long term well-controlled BP, it is evident an increase in arterial local stiffness respect normotensive controls. PP.09.20 AMBULATORY VASCULAR INDEX: A NOVEL MEASURE OF ARTERIAL STIFNNESS IN AMBULATORY CONDITIONS OVER THE 24-HOUR I.N. Posokhov 1 , T. Pereira 2 , S. Omboni 3 . 1 Hemodynamic Laboratory Ltd, Nizhniy Novgorod, Russia, 2 Escola Superior de Tecnologia da Saúde de Coimbra, Instituto Politécnico de Coimbra, Coimbra, Portugal, 3 Clinical Research Unit, Italian Institute of Telemedicine, Varese, Italy Objective: The current hypertension management involves both ambulatory blood pressure (BP) monitoring (ABPM) and evaluation of the arterial stiffness by measuring pulse wave velocity (PWV). Stiffness parameter b is a promising estimate of arterial stiffness characterized by a less dependency on BP. b is used to calculate the well-known cardio-ankle vascular index (CAVI), which is measured in the segment between heart and ankle. However, at present, CAVI may be ob- tained only at rest and thus may not return information on arterial stiffness in the dynamic conditions of everyday life. Recently available technologies now allow 24-h pulse wave analysis (PWA) inte- grated in ABPM devices and may provide an easy way to obtain PWV. They can also make possible to evaluate b in the corresponding segment and ambulatory BP in a single procedure. For methodological analogy with CAVI we decided to call new index AVI, which means Ambulatory Vascular Index. The aim of this part of the pilot study is to evaluate the features of the AVI in healthy volunteers. Design and method: Data of 179 healthy volunteers (BP and PWV) were col- lected with BPLab ® ABPM device and validated Vasotens ® PWA technology. AVI is calculated using BP and PWV of each measurement and then averaged for 24-h period. We used following formula: AVI = 2/P[lnPs/Pd]PWV 2 , where : blood density, P:Ps-Pd or systolic minus diastolic BP. Results: 24-h average AVI in volunteers was 15.4 ± 3.8, while 24-h average PWV was 9.3 ± 1.1 m/s (mean ± SD). There was no correlation between AVI and 24-h systolic BP (r = -0.02, n/s, fig.1, a), but 24-h PWV was significantly associated