Isolated office hypertension: a prehypertensive state?

OBJECTIVE AND METHOD: Isolated office hypertension, defined as hypertensive blood pressure values in a medical setting but normal self-measured or ambulatory-recorded blood pressures, is frequently encountered in clinical practice. Yet, whether this condition represents a transient state in the development of a sustained ambulatory hypertension is still unknown as no long-term analysis of the evolution of ambulatory blood pressure has been carried out in patients with isolated office hypertension. To evaluate whether such patients should be considered as truly normotensive or hypertensive, we have studied the long-term changes in office and ambulatory blood pressures in 81 patients in whom isolated office hypertension was observed between 1982 and 1988. RESULTS: After a 5-6 year follow-up, 60 of the 81 patients had a mean 12 h daytime ambulatory blood pressure greater than 140/90 mmHg, suggesting an evolution towards ambulatory hypertension. The development of hypertension could not be predicted on the basis of the follow-up office blood pressures as these tended to decrease during the follow-up period. CONCLUSIONS: The results of this study suggest that patients with isolated office hypertension should not be considered as truly normotensive individuals. Hence, these patients require a careful medical follow-up. Office blood pressure readings alone, however, do not appear to provide a good indicator of the long-term outcome of isolated office hypertension.

Prevalence of hypertension in schoolchildren based on repeated measurements and association with overweight.

OBJECTIVE: Most studies assess the prevalence of hypertension in pediatric populations based on blood pressure (BP) readings taken on a single visit. We determined the prevalence of hypertension measured on up to three visits in a Swiss pediatric population and examined the association between hypertension and overweight and selected other factors. METHODS: Anthropometric data and BP were measured in all children of the sixth school grade of the Vaud canton (Switzerland) in 2005-2006. 'Elevated BP' was defined according to sex-specific, age-specific and height-specific US reference data. BP was measured on up to two additional visits in children with elevated BP. 'Hypertension' was defined as 'elevated BP' on all three visits. RESULTS: Out of 6873 children, 5207 (76%) participated [2621 boys, 2586 girls; mean (SD) age, 12.3 (0.5) years]. The prevalence of elevated BP was 11.4, 3.8 and 2.2% on first, second and thirds visits, respectively; hence 2.2% had hypertension. Among hypertensive children, 81% had isolated systolic hypertension. Hypertension was associated with excess body weight, elevated heart rate and parents' history of hypertension. Of the children, 16.1% of boys and 12.4% of girls were overweight or obese (CDC criteria, body mass index >or= 85th percentile). Thirty-seven percent of cases of hypertension could be attributed to overweight or obesity. CONCLUSIONS: The proportion of children with elevated BP based on one visit was five times higher than based on three measurements taken at few-week intervals. Our data re-emphasize the need for prevention and control of overweight in children to curb the global hypertension burden.

The Effect of Valsartan versus Non-RAAS Treatment on Autoregulation of Cerebral Blood Flow.

Background: Cerebral autoregulation (CA) is a protective mechanism which maintains the steadiness of the cerebral blood flow (CBF) through a broad range of systemic blood pressure (BP). Acute hypertension has been shown to reduce the cerebrovascular adaptation to BP variations. However, it is still unknown whether CA is impaired in chronic hypertension. This study evaluated whether a strict control of BP affects the CA in patients with chronic hypertension, and compared a valsartan-based regimen to a regimen not inhibiting the renin-angiotensin-aldosterone system (non-RAAS). Methods: Eighty untreated patients with isolated systolic hypertension were randomized to valsartan 320 mg or to a non-RAAS regimen during 6 months. The medication was upgraded to obtain BP <140/90 mm Hg. Continuous recordings of arterial BP and CBF velocity (transcranial Doppler) were performed during periods of 5 minutes, at rest, and at different levels of alveolar CO(2) pressure provided by respiratory maneuvers. The dominant frequency of CBF oscillations was determined for each patient. Dynamic CA was measured as the mean phase shift between BP and CBF by cross-spectral analysis in the medium frequency and in the dominant CBF frequency. Results: Mean ambulatory 24-hour BP fell from 144/87 to 127/79 mm Hg in the valsartan group and from 144/87 to 134/81 mm Hg in the non-RAAS group (p = 0.13). Both groups had a similar reduction in the central BP and in the carotido-femoral pulse wave velocity. The average phase shift between BP fluctuations and CBF response at rest was normal at randomization (1.82 ± 0.08 s), which is considered a preserved autoregulation and increased to 1.91 ± 0.12 s at the end of study (p = 0.45). The comparison of both treatments showed no significant difference (-0.01 ± 0.17 s vs. 0.16 ± 0.16 s, p = 0.45) for valsartan versus non-RAAS groups. The plasmatic level of glycosylated hemoglobin decreased in the valsartan arm compared to the non-RAAS arm (-0.23 ± 0.06 vs. -0.08 ± 0.07%, p = 0.07). Conclusions: In elderly hypertensive men with isolated chronic systolic hypertension, CA seems efficient at baseline and is not significantly affected by 6 months of BP-lowering treatment. This suggests that the preventive effects of BP medication against stroke are not mediated through a restoration of the CA.

Task force IV: Clinical use of ambulatory blood pressure monitoring. Participants of the 1999 Consensus Conference on Ambulatory Blood Pressure Monitoring

OBJECTIVE: To reach a consensus on the clinical use of ambulatory blood pressure monitoring (ABPM). METHODS: A task force on the clinical use of ABPM wrote this overview in preparation for the Seventh International Consensus Conference (23-25 September 1999, Leuven, Belgium). This article was amended to account for opinions aired at the conference and to reflect the common ground reached in the discussions. POINTS OF CONSENSUS: The Riva Rocci/Korotkoff technique, although it is prone to error, is easy and cheap to perform and remains worldwide the standard procedure for measuring blood pressure. ABPM should be performed only with properly validated devices as an accessory to conventional measurement of blood pressure. Ambulatory recording of blood pressure requires considerable investment in equipment and training and its use for screening purposes cannot be recommended. ABPM is most useful for identifying patients with white-coat hypertension (WCH), also known as isolated clinic hypertension, which is arbitrarily defined as a clinic blood pressure of more than 140 mmHg systolic or 90 mmHg diastolic in a patient with daytime ambulatory blood pressure below 135 mmHg systolic and 85 mmHg diastolic. Some experts consider a daytime blood pressure below 130 mmHg systolic and 80 mmHg diastolic optimal. Whether WCH predisposes subjects to sustained hypertension remains debated. However, outcome is better correlated to the ambulatory blood pressure than it is to the conventional blood pressure. Antihypertensive drugs lower the clinic blood pressure in patients with WCH but not the ambulatory blood pressure, and also do not improve prognosis. Nevertheless, WCH should not be left unattended. If no previous cardiovascular complications are present, treatment could be limited to follow-up and hygienic measures, which should also account for risk factors other than hypertension. ABPM is superior to conventional measurement of blood pressure not only for selecting patients for antihypertensive drug treatment but also for assessing the effects both of non-pharmacological and of pharmacological therapy. The ambulatory blood pressure should be reduced by treatment to below the thresholds applied for diagnosing sustained hypertension. ABPM makes the diagnosis and treatment of nocturnal hypertension possible and is especially indicated for patients with borderline hypertension, the elderly, pregnant women, patients with treatment-resistant hypertension and patients with symptoms suggestive of hypotension. In centres with sufficient financial resources, ABPM could become part of the routine assessment of patients with clinic hypertension. For patients with WCH, it should be repeated at annual or 6-monthly intervals. Variation of blood pressure throughout the day can be monitored only by ABPM, but several advantages of the latter technique can also be obtained by self-measurement of blood pressure, a less expensive method that is probably better suited to primary practice and use in developing countries. CONCLUSIONS: ABPM or equivalent methods for tracing the white-coat effect should become part of the routine diagnostic and therapeutic procedures applied to treated and untreated patients with elevated clinic blood pressures. Results of long-term outcome trials should better establish the advantage of further integrating ABPM as an accessory to conventional sphygmomanometry into the routine care of hypertensive patients and should provide more definite information on the long-term cost-effectiveness. Because such trials are not likely to be funded by the pharmaceutical industry, governments and health insurance companies should take responsibility in this regard.

Arterial hypertension after surgical closure of omphalocele and gastroschisis.

Arterial hypertension has been reported as a complication of surgical closure of an abdominal wall defect. No report studying the incidence, the characteristics and the clinical significance of hypertension after surgical correction of an omphalocele or gastroschisis has been published so far. The medical records of all newborns with surgically corrected gastroschisis or omphalocele identified in two centers were retrospectively evaluated. Arterial hypertension was defined as a mean daily systolic and/or diastolic blood pressure value higher than the 95 percentile for age and/or weight, according to literature data. The timing of surgery, weight gain, plasma creatinine and the use of diuretics or vasoactive drugs were compared between the groups with and without hypertension. Seventy-two patients were identified and included in the study, 29 with omphalocele and 43 with gastroschisis. Those with omphalocele were born at a mean age of 37.3+/-2.6 weeks with a mean birth weight of 2,971+/-715 g, and those with gastroschisis were born at 36.1+/-2.0 weeks with a mean birth weight of 2,527+/-498 g. Blood pressure values of 66 patients were available for analysis. Of the omphalocele patients, 46.2% (12/26) developed systolic hypertension, compared to 17.5% (7/40) of the patients with gastroschisis (P =0.024). Hypertension was always transient, lasting an average of 4 and 1 day in the omphalocele and gastroschisis groups, respectively. Two patients with omphalocele were given anti-hypertensive therapy. There was no difference between patients with or without hypertension regarding weight gain, use of vasoactive drugs or diuretics, mean weekly creatinine values or the timing of surgery. Newborns with an abdominal wall defect frequently present with transient arterial hypertension. Hypertension occurs significantly more often, is more severe and lasts longer in patients with omphalocele than in patients with gastroschisis. In both groups, hypertension is transient and rarely requires therapy. The cause of hypertension remains unclear.

Pulmonary hypertension complicating isolated atrial septal defect.

Atrial septal defect (ASD) typically is asymptomatic in infancy and early childhood and elective defect closure usually is performed at an age between 4 - 6 years. Severe pulmonary hypertension (PHT) complicating an ASD is seen in adulthood and has only occasionally been reported in small children. A retrospective study was undertaken to evaluate the incidence of severe PHT complicating an isolated ASD and requiring early surgical correction in the fi rst year of life. 355 pediatric patients underwent treatment for an isolated ASD either surgically or by catheter intervention during a 10 year period (1996 - 2006) at two tertiary referral centers. 297 patients had secundum ASD and 58 primum ASD with mild to moderate mitral regurgitation. 8 infants were found with isolated ASD (six with secundum and two with primum ASD) associated with signifi cant PHT, accounting for 2.2% of all ASD patients in our centers. These 8 infants had invasively measured pulmonary artery pressures between 50 and 100% of systemic pressure. Median size of the ASD at the time of surgery was 14mm (7 - 20). They were operated in the fi rst year of life and had complicated postoperative courses requiring specifi c treatment for PHT for up to 16 weeks (median 12) postoperatively. Compared to ASD patients without PHT these infants had prolonged postoperative ICU stay of 5 - 9 days (median 8) and prolonged perioperative overall hospital stay of 8 - 32 days (median 15). Ultimate outcome in all 8 infants was good with persistent normalization of pulmonary pressures during mid-term follow-up of between 8 to 60 months (median 28). All other ASD patients had normal pulmonary pressures and mean age at defect closure was higher being 6.2 years for secundum ASD and 3.2 years for primum ASD. In conclusion, ASD is rarely associated with signifi cant PHT in infancy but then requires early surgery to normalize the prognosis of the patients.

Frequency of severe pulmonary hypertension complicating "isolated" atrial septal defect in infancy.

Atrial septal defects (ASDs) are typically asymptomatic in infancy and early childhood, and elective defect closure is usually performed at ages of 4 to 6 years. Severe pulmonary hypertension (PH) complicating an ASD is seen in adulthood and has only occasionally been reported in small children. A retrospective study was undertaken to evaluate the incidence of severe PH complicating an isolated ASD and requiring early surgical correction. During a 10-year period (1996 to 2006), 355 pediatric patients underwent treatment for isolated ASDs either surgically or by catheter intervention at 2 tertiary referral centers. Two hundred ninety-seven patients had secundum ASDs, and 58 had primum ASDs with mild to moderate mitral regurgitation. Eight infants were found with isolated ASDs (6 with secundum ASDs and 2 with primum ASDs) associated with significant PH, accounting for 2.2% of all patients with ASDs at the centers. These 8 infants had invasively measured pulmonary artery pressures of 50% to 100% of systemic pressure. They were operated in the first year of life and had complicated postoperative courses requiring specific treatment for PH for up to 16 weeks postoperatively. The ultimate outcomes in all 8 infants were good, with persistent normalization of pulmonary pressures during midterm follow-up of up to 60 months (median 28). All other patients with ASDs had normal pulmonary pressures, and the mean age at defect closure was significantly older, at 6.2 years for secundum ASDs and 3.2 years for primum ASDs. In conclusion, ASDs were rarely associated with significant PH in infancy but then required early surgery and were associated with excellent midterm outcomes in these patients.

Electronic compliance monitoring in resistant hypertension: the basis for rational therapeutic decisions.

OBJECTIVE: Incomplete compliance is one of several possible causes of uncontrolled hypertension. Yet, non-compliance remains largely unrecognized and is falsely interpreted as treatment resistance, because it is difficult to confirm or exclude objectively. The goal of this study was to evaluate the potential benefits of electronic monitoring of drug compliance in the management of patients with resistant hypertension. METHODS: Forty-one hypertensive patients resistant to a three-drug regimen (average blood pressure 156/ 106 +/- 23/11 mmHg, mean +/- SD) were studied prospectively. They were informed that for the next 2 months, their presently prescribed drugs would be provided in electronic monitors, without any change in treatment, so as to provide the treating physician with a measure of their compliance. Thereafter, patients were offered the possibility of prolonging the monitoring of compliance for another 2 month period, during which treatment was adapted if necessary. RESULTS: Monitoring of compliance alone was associated with a significant improvement of blood pressure at 2 months (145/97 +/- 20/15 mmHg, P < 0.01). During monitoring, blood pressure was normalized (systolic < 140 mmHg or diastolic < 90 mmHg) in one-third of the patients and insufficient compliance was unmasked in another 20%. When analysed according to tertiles of compliance, patients with the lowest compliance exhibited significantly higher achieved diastolic blood pressures (P = 0.04). In 30 patients, compliance was monitored up to 4 months and drug therapy was adapted whenever necessary. In these patients, a further significant decrease in blood pressure was obtained (from 150/100 +/- 18/15 to 143/94 +/- 22/11 mmHg, P = 0.04/0.02). CONCLUSIONS: These results suggest that objective monitoring of compliance using electronic devices may be a useful step in the management of patients with refractory hypertension, as it enables physicians to take rational decisions based on reliable and objective data of drug compliance and hence to improve blood pressure control.

Hypertension: which aspects of hypertension should we impact on and how?

Cardiovascular complications may, to a large extent, be prevented by lowering blood pressure in hypertensive patients. International recommendations currently stress the importance of reaching values of below 140/90 mmHg in each patient or even lower in the case of concomitant diabetes or renal impairment. It is currently considered crucial to control the systolic pressure as well as the diastolic pressure, in particular because the relationship between cardiovascular risk and blood pressure is closer for the systolic than the diastolic value. An increase in systolic pressure is in itself a sign of the stiffening of the arterial tree. In most patients, the target pressure may only be reached by combining several different antihypertensive agents. In the STRATHE Study, a greater antihypertensive efficacy, in particular on systolic pressure, was obtained by instituting treatment with a fixed low-dose combination of an angiotensin-converting enzyme inhibitor (perindopril) and a diuretic (indapamide), in comparison with other therapeutic strategies based on single-agent therapy. Fixed-dose antihypertensive combinations have now become a validated option for initiating antihypertensive treatment.

Caffeine intake and CYP1A2 variants associated with high caffeine intake protect non-smokers from hypertension.

The 15q24.1 locus, including CYP1A2, is associated with blood pressure (BP). The CYP1A2 rs762551 C allele is associated with lower CYP1A2 enzyme activity. CYP1A2 metabolizes caffeine and is induced by smoking. The association of caffeine consumption with hypertension remains controversial. We explored the effects of CYP1A2 variants and CYP1A2 enzyme activity on BP, focusing on caffeine as the potential mediator of CYP1A2 effects. Four observational (n = 16 719) and one quasi-experimental studies (n = 106) including European adults were conducted. Outcome measures were BP, caffeine intake, CYP1A2 activity and polymorphisms rs762551, rs1133323 and rs1378942. CYP1A2 variants were associated with hypertension in non-smokers, but not in smokers (CYP1A2-smoking interaction P = 0.01). Odds ratios (95% CIs) for hypertension for rs762551 CC, CA and AA genotypes were 1 (reference), 0.78 (0.59-1.02) and 0.66 (0.50-0.86), respectively, P = 0.004. Results were similar for the other variants. Higher CYP1A2 activity was linearly associated with lower BP after quitting smoking (P = 0.049 and P = 0.02 for systolic and diastolic BP, respectively), but not while smoking. In non-smokers, the CYP1A2 variants were associated with higher reported caffeine intake, which in turn was associated with lower odds of hypertension and lower BP (P = 0.01). In Mendelian randomization analyses using rs1133323 as instrument, each cup of caffeinated beverage was negatively associated with systolic BP [-9.57 (-16.22, -2.91) mmHg]. The associations of CYP1A2 variants with BP were modified by reported caffeine intake. These observational and quasi-experimental results strongly support a causal role of CYP1A2 in BP control via caffeine intake.

Changes in the vascular reactivity of the isolated tail arteries of spontaneous and renovascular hypertensive rats to endogenous and exogenous noradrenaline.

We have investigated the changes in the responses to noradrenaline of isolated tail arteries of spontaneously hypertensive (SHR) and renovascular hypertensive rats (Wistar-Kyoto: two-kidney, one-clip model, WKY:2K1C) compared with normotensive (Wistar-Kyoto, WKY) rats. Renovascular hypertension was induced by 4 weeks' unilateral renal artery clipping. Arteries were vasoconstricted with exogenous noradrenaline, electrical field stimulation or high potassium. The effects of the latter two stimuli were abolished by reserpine and so were presumably dependent on the presence of endogenous noradrenaline. In the SHR the maximal vasoconstriction produced by all three stimuli was greater than in WKY. Dose-response curves were steeper and there was no change in threshold. Vascular mass was greater. We interpret these results as showing an increase in vascular reactivity in the SHR caused by structural adaptation. The WKY:2K1C responses to noradrenaline could also be explained in terms of structural adaptation but there was no increase in vascular mass. Sensitivity to potassium and electrical stimulation was decreased, suggesting a defect in vascular neurotransmission. This was supported by the observations of a decreased arterial noradrenaline content and of decreased sensitivity to cocaine.