[Is the white coat effect an alert reaction?]. / L'effet blouse blanche est-il une réaction d'alerte?

Is the white coat effect an alert reaction? In this cross-sectional study we compared the white coat effect on systolic blood pressure with the systolic blood pressure reactivity obtained during a stress test. The influence of the sympathetic system (LF band of systolic BP) and the parasympathetic system (HF band of pulse rate) on white coat systolic blood pressure and stress test systolic blood pressure were analysed. We stratified 174 subjects into two groups, according to their blood pressure: hypertensives (HT, n=44, BP>140/90 mmHg) and normotensives (NT, n=130). The BP was recorded during an occupational health consultation, over 24 hours, and beat to beat during a stress test (Finapress). White coat systolic BP was calculated as the difference between the consultation BP and the average systolic BP over 24 hours. The white coat systolic BP was not related with an increase in pulse rate. In contrast, during the stress test the increases in systolic BP and pulse rate were correlated (r=0.44; p<0.001). The white coat systolic BP was lower than the stress test systolic BP in the NT (6.6 +/- 7.2 vs 23 +/- 12 mmHg; p<0.001) and in the HT (16 +/- 11 vs 29 +/- 17 mmHg; p<0.001). The HT had a lower parasympathetic index than the NT (0.45 +/- 0.43 vs 0.92 +/- 0.83 bpm2; p<0.001). In the HT the white coat systolic BP was positively correlated with the stress test systolic BP (r=0.47: p<0.01) and negatively with the parasympathetic activity index. In conclusion, for recently diagnosed and untreated HT an early alteration of the parasympathetic system reveals that the white coat effect is a low amplitude alert reaction.

[Professional stress and blood pressure reactivity to stress do not predict blood pressure at 5 years]. / Le stress professionnel et la réactivité pressionnelle au stress ne prédisent pas la pression artérielle à 5 ans.

High job strain has been reported to be associated with higher blood pressure. Job strain could lead to hypertension if individual perception of stress or cardiovascular reactivity to stress are high. We report the results of the first five-year follow up study, which aimed to assess the respective influences of perception of professional strain and cardiovascular reactivity to a mental stress test on BP. A cohort of 292 healthy subjects (mean +/- SEM, 38 +/- 1 years) was followed for progression to hypertension outcome which was defined as an increase in SBP or DBP higher than 7 mmHg or a DBP higher than 95 mmHg during the follow-up. The high strain (HS) group representing 20.9% of the subjects was compared with the remaining subjects (NHS). Similarly the 20.9% subjects with the highest BP stress reactivity (HR) were compared with the remaining subjects (NHR). The Kaplan-Meier survival estimates revealed that neither high job strain, nor high stress reactivity, increased incidence of progression to hypertension. Age, alcohol, salt diet, BMI, and occupation did not interfere with our results. In conclusion, high stress cardiovascular reactivity and high job strain do not appear to be major risk markers for future high BP in healthy young adults. Stress could be associated with high BP at a short term and could explain high blood pressure in a long run only in stress-sensible subjects.

[Phenotypes of essential arterial hypertension in Caribbean women]. / Phénotypes de l'hypertension artérielle essentielle chez les femmes antillaises.

UNLABELLED: The characterisation of phenotypes of patients with essential hypertension (EH) is an important pre-requisite for genetic research. The present study compares clinical and renal function parameters in 2 groups of patients from different origins. METHOD: Out of a cohort of essential hypertensives disclosed on routine work medical examinations, 21 caucasian (CC) women were paired with 21 Caribbean (CB) women. In the 2 groups we recorded family history of hypertension (FHH), duration of hypertension, BMI, salt intake based on 24 h urinary sodium excretion, microalbuminuria, and blood pressure (BP). Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured with inulin and para-amino-hippuric acid clearances. Plasma active renin (AR) and aldosterone (Aldo) levels were measured by immuno-assays. White coat (WC) effect was assessed on the difference between BP values measured on medical visits and by the nurses on clearance measurements. Anova and t-test were used for analysis, statistical significance was assumed for p < 0.05. RESULTS: Casual BP values were 150/94 mmHg in CB and 153/95 mmHg in CC. There were no significant differences on BMI (CB 30.6 kg/m2 vs CC 27.1 kg/m2). AR (CB 6.6 pg/mL vs CC 8.7 pg/mL) and Aldo (CB 195.1 pmol/L vs CC 202.8 pmol/L) provided an equivalent dietary salt intake (CB 11.2 g/d vs CC 10.7 g/d). Mother FHH was found predominantly in CB women (60% vs 30% in CC, p < 0.05), whereas paternal FHH was more frequent in CC women (21% vs 8% in CB, p < 0.05). At the same age, duration of hypertension was longer by 1 year in CB. White coat effect was more marked in CC (BP > 30 mmHg: 40% in CC vs 5% in CB, p < 0.05). GFR values were normal and similar in CB and CC women. But a significantly lower RPF was measured in CB (489 vs 542 mL/min/1.73 m2 in CC, p < 0.05). Higher filtration fraction and microalbuminuria were also observed in CB women. CONCLUSION: Essential hypertension occurs at younger ages in Caribbean women. The decrease in RPF could be genetically determined and is likely to participate in early onset of hypertension, as previously described in young normotensive subjects. In paired women, we did not found significant differences in active renin and aldosterone levels. The ongoing longitudinal study should contribute to assess the consequences of these findings on renal prognosis and the effects of antihypertensive therapy.

Hypertension arterielle apres transplantation renale : Influence du profil tensionnel au stade de dialyse

L'objectif de ce travail cooperatif est d'etudier l'influence d'une hypertension pre-existante en dialyse (D); sur la frequence de l'hypertension arterielle (HTA) chez les transplantes renaux (TR); et de definir ses caracteristiques cliniques