To provide updated, evidence-based recommendations for the diagnosis and assessment of high blood pressure in adults.
For people with high blood pressure, the assignment of a diagnosis of hypertension depends on the appropriate measurement of blood pressure, the level of the blood pressure elevation, the duration of follow-up and the presence of concomitant vascular risk factors, target organ damage and established atherosclerotic diseases. For people diagnosed with hypertension, defining the overall risk of adverse cardiovascular outcomes requires laboratory testing, a search for target organ damage and an assessment of the modifiable causes of hypertension. Out-of-clinic blood pressure assessment and echocardiography are options for selected patients.
People at increased risk of adverse cardiovascular outcomes and were identified and quantified.
Medline searches were conducted from the period of the last revision of the Canadian recommendations for the management of hypertension (May 1998 to October 2000). Reference lists were scanned, experts were polled, and the personal files of the subgroup members and authors were used to identify other studies. All relevant articles were reviewed and appraised, using prespecified levels of evidence, by content experts and methodological experts.
A high value was placed on the identification of people at increased risk of cardiovascular morbidity and mortality.
The identification of people at higher risk of cardiovascular disease will permit counselling for lifestyle manoeuvres and the introduction of antihypertensive drugs to reduce blood pressure for patients with sustained hypertension. In certain settings, and for specific classes of drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and/or mortality.
The present document contains detailed recommendations pertaining to aspects of the diagnosis and assessment of patients with hypertension, including the accurate measurement of blood pressure, criteria for the diagnosis of hypertension and recommendations for follow-up, routine and optional laboratory testing, assessment for renovascular hypertension, home and ambulatory blood pressure monitoring, and the role of echocardiography in hypertension.
All recommendations were graded according to strength of the evidence and voted on by the Canadian Hypertension Recommendations Working Group. Only the recommendations achieving high levels of consensus are reported here. These guidelines will be updated annually.
These recommendations are endorsed by the Canadian Hypertension Society, The Canadian Coalition for High Blood Pressure Prevention and Control, The College of Family Physicians of Canada, The Heart and Stroke Foundation of Canada, The Adult Disease Division and Bureau of Cardio-Respiratory Diseases and Diabetes at the Centre for Chronic Disease Prevention and Control of Health Canada.
The diagnosis of mild hypertension and the treatment of hypertension require accurate measurement of blood pressure. Blood pressure readings are altered by various factors that influence the patient, the techniques used and the accuracy of the sphygmomanometer. The variability of readings can be reduced if informed patients prepare in advance by emptying their bladder and bowel, by avoiding over-the-counter vasoactive drugs the day of measurement and by avoiding exposure to cold, caffeine consumption, smoking and physical exertion within half an hour before measurement. The use of standardized techniques to measure blood pressure will help to avoid large systematic errors. Poor technique can account for differences in readings of more than 15 mm Hg and ultimately misdiagnosis. Most of the recommended procedures are simple and, when routinely incorporated into clinical practice, require little additional time. The equipment must be appropriate and in good condition. Physicians should have a suitable selection of cuff sizes readily available; the use of the correct cuff size is essential to minimize systematic errors in blood pressure measurement. Semiannual calibration of aneroid sphygmomanometers and annual inspection of mercury sphygmomanometers and blood pressure cuffs are recommended. We review the methods recommended for measuring blood pressure and discuss the factors known to produce large differences in blood pressure readings.
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To provide health care professionals with guidelines on the use of blood pressure self-measurement.
Recommendations were devised after consideration of expert reviews and guidelines, personal files, international standards documents, personal communication with investigators and the results of a MEDLINE search (1966-94) using the term 'blood pressure determination'. BENEFITS, HARMS, COSTS: Self-measurement of blood pressure can be used to detect white coat hypertension, monitor changes in blood pressure closely, more rapidly achieve desired blood pressure goals, increase adherence to antihypertensive therapy and improve patient self-reliance. However, self-measured blood pressure readings may be misleading because there is insufficient normative, prognostic and outcome data and because some patients may not take accurate measurements. The use of self-measurement of blood pressure has a relatively small direct cost and may result in an overall reduction in treatment costs.
Self-measured blood pressure readings can be a valuable supplement to clinic (or office) blood pressure readings. However, self-measurement is appropriate neither for patients who are physically or mentally incapable of accurate assessment and interpretation of readings nor for those who do not want to participate. Patients who self-monitor blood pressure require careful training in blood pressure measurement and instruction on the recording and interpretation of blood pressure readings. Advice to patients using monitoring equipment must take into account the needs and abilities of the patient. Although only a few electronic devices for the self-measurement of blood pressure have met recommended performance standards, their use may be more appropriate for some patients and the training requirements fewer than if manual devices are used.
The guidelines of several expert groups were examined in the preparation of these recommendations. The recommendations were presented at the World Conference on Hypertension Control in 1995 and were reviewed by the parent societies of the Canadian Coalition for High Blood Pressure Prevention and Control.