Decision-making in hypertension: Increasing role of ambulatory blood pressure monitoring (ABPM)

110A

ASH XI ABSTRACTS

AJH-APRIL 1996-VOL. 9, NO.4, PART 2

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AMBULATORY BLOOD PRESSURE MONITORING IN NORMOfENSIVE AND HYPERTENSIVE OBESE SUBJECfS 1Maldonado. J. Topouchian, A.M. Brisae, J. Raison, L.A. Providencla, M. Safar, and R. Asmar·. Institut de Recherche et Formation Cardiovasculaue, Pans, France· Hospltais da Uruversidade de Coimbra, Portug;U The relationslup between overweight and hypertension .s a discussed topic in the current bterature. Besides the physiopathologic concepts involved, the ntain reasons for such a discussion are related to obesity definition, patients selection, cuff Size and recruitment of patients based in casual BP measurements The purpose of thiS study IS to evaluate the circadian blood pressure profile in patients WIth obeSity, and to compare it to those observed in matched normal weight hypertensive and normotensive subjects. The study was carried out In 92 untreated subjects (33 men and 59 wome~ mean age 43 12 ± II 84.years). Body mass index (BMI) (Kglm ) was used to select obese patients (BMI > 30 Kg I m2) They were healthy normotensive obese (n = 28), hypertenSive obese (n = 18), healthy normal weight (n = 28) and normal weight hypertensive patients (n = 18). Ambulatory blood pressure recordmgs were performed norunvaslvely usmg a automated apparatus with measurements performed at 15 mmutes mterval over 24 hours. Mean values calculated from the day time, night time and the full 24 hours IM!re used for statistical analysis and circadian vanablhty was assessed on the basiS of the absolute standard deviation (SD) and from the day-night lhfference. evaluated m each subject. Obese hypertenSive patients had a less marked systobc fall m blood pressure at Dlght than the normal weight hypertenSive patients (9.09 ± 6.25% versus 12.86 ± 43 % ; p < 0.05). In what concerns to standard deviation variabihty of blood pressure, it IS Significantly hIgher m hypertenSive and m obese patients. ThiS study shows that obeSity does not, for itself, impose major changes m circalhan blood pressure paUern, although may have influence on BP vanabihty. However, when obeSity IS associated with hypertension not only BP variability IS changed, but the night fall in BP is also imparred These findings are presumably related to humoral and hormonal changes involved in the patophysiology of hypertension. in obese pallents

REPEATED MEASUREMENTS OF NON INVASIVE AMBULATORY BLOOD PRESSURE: DlSTINCfION BETWEEN REPRODUCIBILITY AND THE PROPER EFFECT OF PLACEBO !!. Asmar•• S Boutel~ M. Chaignon. J Guedon, J Topouchi~ J M. Mall1on, M. Safar. HOpital BrOUSS8ls, Pans , France Non invasive ambulatory blood pressure (BP) IS more reproducible and less affected by placebo than the clinic BP measurements. Most of these evidences were obtamed in small grou", of patIents or from a parallel group study design w1uch did not allow to analyse separatly the reprodUCibility from the "spectfic" effect of placebo. In this study, 34 hypertenSive outpatIents were randonuzed after 4 weeks preselection penod 10 2 grou", cross over study design . one group received placebo for 4 weeks while the other form the control group (reproduciblhty). Then, they cross-overed treatment for another 4 weeks ClImc and ambulatory BP were measured before the randomization and at the end of each penod, usmg mercury manometer and 24 hour non IOvaslve ambulatory BP mODltor Placebo showed a Slgntficant reduction in systolic and lhastolic cllmc BP (- 3 4 ± 13 mmHg and - 3.6 ± 8 mmHg respecl1vely ,P < O.OS), but not ID 24 hour, daytime and nighllme BP. Circadian hourly curves of BP and heart rate were Virtually supenmposable. In the 13 placebo responder patients selected on the basiS of chmc BP, placebo decreases climc BP and also reduces systolic and diastolic ambulatory BP mamly dunng the day penod(-5 2 ±6.2 mmHgand- 4.8 ±7.8 mmHg, P< 0 05) ThiS effect IS specIfic to placebo adrmmstratlon smce the measurements without treatment lhd not show any significant lhfference. The companson with the non placebo responders showed a 10000r baseline values of ambulatory systolic BP recorded dunng the 24 hour, daytime and mghtlme 10 the placebo responder group These results mlhcate that 24 hour ambulatory BP average IS not affected by placebo 10 group of patients but that a placebo effect occurs mamly dunng the daytime m the chnlc placebo-responder pallents • the BP reduction IS related to a specific effect of placebo Although. this study clearly polDtS out the necessIty to mclude placebo and ambulatory momtonng 10 the therapeutIcal and pharmacolOgIcal trials

Key Words:

ambulatory blood pressure monitorlDg - obeSity circadian variablbty - blood pressure vanablbty

Key Words:

Blood pressure, placebo, reprodUCibility

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DECISION-MAKING IN HYPERTENSION: INCREASING ROLE OF AMBULATORY BLOOD PRESSURE MONITORING (ABPM). ~ R. sanchez·, Y. Plotqum. M. Amol~ P. Rodriguez. M Oiaz, A

SIMULTANEOUS AND SEQUENTIAL SAME·ARM MEASUREMENTS IN THE VALIDATION STUDIES OF AUTOMATED BLOOD PRESSURE (BP) MEASURING DEVICES. R Livi, L Teghini. S Cagnoni, and PT Scarpelli. Institute of Clinical Medicine IV, Postgraduate School Nefrology and Department of Electronic Engineering, University of Florence, Italy. Both the AAMI and the BHS guidelines for the validation studies of automated bp measuring devices recommended In thelf initial versions to compare simultaneous same-arm bp readings taken by the device being tested and by trained observers with a mercury sphygmomanometer. In 1993, the BHS protocol adopted sequential measurements and modified final grading criteria to accomplish with the expected higher device-observer disagreement. ThiS choice was justified because the rapid deflation rate of many devices did not permit accurate simultaneous readings. Simultaneous and sequential measures have been used in the validation study of a new oscillometric ambulatory bp monitoflng device (Daypress 500, Neural Instruments, Italy) The mean absolute differences between observer's consecutive (within 1 minute) measures (255 observations) were 3.4 (range 0-20) and 2.5 (range 0-12) mmHg for systolic (SBP) and diastolic bp (DBP), respectively SBP differences were inversely related to heart rate (r :: -0.22, p
Villamil. H Baghvo· Grupo Argentino para el Estudlo de la Hlpertensi6n

Arterial (GAEHTA). Buenos Aires. Argentina

In order to detcnninc the mnuenc:c of the ABPM on the cllmcal dccislon~ making process. a multicentric prospective study was carried out In patients consultmg at Hypertension Centers. Patient1s blood pressure (BP) measurements

were oblalned sequenti.lly at the clinic (CBP). at home (HBP) and With ABPM

(ABP) under the same conditions of treatment. accordmg to standard chmcal

procedures. Each researcher selected a decISion based on BP d.ta m three steps along the study' with CBP (first decISIon). plus HBP (second decision) and plus ABPM (third deCIsion) OptIons conSidered In steps two and three were dichotomously applied deciSion could be the same or different to the prevIous

one. Final decISion depended on researche~s judgment According to the agreemenl between CBP and ABPM d.... and uSing as a cut-off BP limits 140 andlor 90 mm Hg (systolic, diastolic) patients were classified as normotensive (NT), hypertenSIve (HT), whlte-<:oat hypertensive (WCHn If only CBP was high and occull hypertenSIve (OHT) if only ABP was hIgh A number of 137 patIents were sludied. 81 women, age 57 ± 14 years. 79 (58%) under antihypertenSIve trealment. CBP' 150±17 /89±9 (from a mean of 8 BP measurements) was hIgher (p < 0.001) than HBP 144±16 / 86±8 (from a mean of 6 BP measurements) and also higher than ABP (day.time average): 139±14 /86±9 lmm Hg. systolic/diastolic BPJ. The correlatIon Index between different methods was. CBP·HBP r 0 57 / 0.40. CBP-ABPM r 0 46 / 0 34 and HBP-ABPM r' 039 / 0.33 (systolic/diastolic). In a subgroup of 78 patients lell ventricular mass index (LVMI) was avaIlable and the correl.tlon Index or LVMI· systolic BP was ror CBP r. 027. ror HBP r 0.24 and ror ABP r: 0.37. Along the study the first deciSion remained IOvarrable in 61 subjects (45%), and the thud

deciSIon was exclusively determinant In 35 subjects (26%). but as ABPM

confirmed or modified the sec:ond deciSion, hence its total gravitation In the final deciSion was 55%. Change 10 decision was found to be less probable when

diastolic CBP was > 100 mm or Hg (16% vs 54%, X'. p' 0 003) Classification I:ndings by CBP .nd ABP were. 20 NT (15%), 67 HT (49"10). 12 OHT (7%) and 38 WCHT (28%). HBP was not useful In order to Identify Ihe OHT In 37% or the pallents under antlhlpertenslve treatment the deciSion changed after ABPM It IS concluded that in usual medical care in hypertenSion centers, the data

rrom ABPM modlry the cllmcal conduct in a greal proportion or patients. m.lnly m those whose d,aslohc CBP IS" 100 mm Hg The design oflhe study. renecting

(he clinical practice. stresses the increasmg role of ABPM on cllmcal deCISionmaking. due to the discrepanCies between CBP and ABP measurements and the researchers' preference for the lauer

Key Words:

Ambulatory blood pressure monitoring. Clime blood

pressure. Home blood pressure.

Key Words:

blood pressure, measure, automated device validation