Acta cardiologica. Supplementum最新文献

Much circumstantial and some direct evidence links a high sodium, low potassium intake to the development of essential hypertension. However, studies to prove a definite causative relationship in man are unlikely to be done for the practical reason that they need to carried out over a whole generation. Restriction of sodium intake does lower blood pressure in many hypertensive subjects. This fall appears to be mediated in part by a diminished renin response to the sodium restriction as blood pressure becomes more severe. Less substantive evidence also suggests that increasing potassium intake may lower blood pressure but this effect seems to be more apparent when both animals and man are on a high intake. It would seem sensible, therefore, in the light of present knowledge, to advise communities that have a high sodium, low potassium diet they may benefit from a reduction in sodium and an increase in potassium intake. Patients who are already known to have high blood pressure should be advised to reduce sodium intake along with other non-pharmacological advice. In some patients this will be sufficient to control the blood pressure. In others who may then require drug treatment, the blood pressure lowering effect of beta-blockers and converting enzyme inhibitors will be enhanced by the sodium restriction.

The high-risk population strategy of coronary heart disease prevention are not alternatives but complement each other, both being parts of a comprehensive community programme. High-risk persons must be detected through screening and require more individual and intensive protection than persons at lesser risk for whom the population approach provides adequate preventive care. The relative effectiveness of the two strategies may be compared, using data from prospective epidemiological studies. The high-risk strategy alone compares well with a limited population strategy alone but the balance is shifted in favour of the population at large. In practice, it does not matter to compare the two strategies in isolation but to assess their effectiveness in combination; it can be shown that the combined effect is likely to make a major dent in the burden of disease in the population. It used to be thought and hoped that the discovery of new and more powerful risk factors would discriminate more sharply between future cases and non-cases of coronary heart disease and thus concentrate the majority of new events in a minority of the population. An attempt was made to show that new advances will add to the preventive potential inherent in risk factors but are not likely to identify future victims of the disease with such precision that the high-risk strategy would eventually supplant the population strategy. Instead, new screening strategies must be developed to detect and protect to the greatest possible extent all the risk carriers who are scattered, in terms of single and multiple risk factors, all-over the population. A major responsibility for the effectiveness of the high-risk strategy is carried by the practicing physician, to select the best treatment for individuals and their families and to encourage adherence to a new life style, as well as compliance with drug therapy, if indicated.

An impressive number of patients has been followed in intervention trials, some of them carefully designed and executed. The different intervention trials in hypertensives are compatible with the hypothesis that hypotensive drug treatment can decrease cardiovascular mortality mainly by decreasing cerebrovascular mortality. A decrease in fatal and non-fatal cardiovascular event rate is mainly due to the decrease in cerebrovascular events. On the basis of these trials the expert committee of the WHO and ISH recommend first general hygienic measures. When the blood pressure remains above 100 mm Hg after 3 months or above 95 mm Hg after 6 months follow-up, hypotensive drugs should be considered. It is not established whether the hypotensive drug treatment is advisable in: --symptomless patients with isolated systolic hypertension, --hypertensive patients above age 80. Sudden reduction in blood pressure should be avoided but whether a progressive reduction of the systolic blood pressure below 140 mm Hg and a diastolic blood pressure below 85 mm Hg is dangerous or advantageous remains to be established.