Incidence of hypertension in the Framingham Study.

Incidence and trends in incidence of definite hypertension were analyzed based on 30 years follow-up of 5,209 subjects in the Framingham Heart Study cohort. Based on pooling of 15 two-year periods, hypertension incidence per biennium increased with age in men from 3.3 per cent at ages 30-39 to 6.2 per cent at ages 70-79, and in women from 1.5 per cent at ages 30-39 to 8.6 per cent at ages 70-79. No consistent trend in incidence rates was evident for either sex from the 1950s through the 1970s. The proportion of hypertensive subjects receiving antihypertensive medication has increased since 1954-58 and exceeded 80 per cent for both men and women ages 60-89 years in 1979-81. Incidence data presented in this report may serve as a baseline for assessing the impact of future public health efforts in the primary prevention of hypertension.     

The J-curve relationship of treated diastolic blood pressure to mortality risk: Is it real? Is it clinically meaningful?

Low diastolic blood pressure is alleged to impose excess cardiovascular disease (CVD) risk in patients with treated hypertension, impeding aggressive reduction of blood pressure. Most investigations that assessed the potential J-shaped relations of diastolic blood pressure and adverse outcomes have not adequately considered systolic or pulse pressure in statistical analyses. An overview of hypertension trials indicates that lowering elevated blood pressure reduces the risk of CVD outcomes irrespective of the associated decrease in diastolic pressure, even if the achieved diastolic pressure averages less than 70 mm Hg. The Framingham study investigations have determined that the increased CVD incidence observed at low diastolic blood pressure levels is confined largely to persons with concomitantly increased systolic pressure. This finding of no true excess risk at low diastolic blood pressure agrees with the results of trials that have evaluated the J-curve phenomenon adjusting for systolic pressure. Aggressively treating systolic hypertension appears to produce no cause for alarm.     

7-甲氧基-4′-羟基-3′-二乙胺甲基异黄酮(MHDF)对大鼠血流动力学和主动脉的作用

本实验观察了MHDF对整体大鼠血流动力学和离体大鼠胸主动脉的作用。结果表明iv MHDF(3～12.8 mg/kg)能降低大鼠左心室±dp/dt_max,V_max,V_pm和LVSP,延长T-dp/dt_max,减慢心率。MHDF还能舒张大鼠胸主动脉,ED₅₀为6.5×10^-6mol/L;非竞争拮抗NA和CaCl₂致主脉收缩,pD₂′为3.11±0.21和3.73±0.07;抑制高K⁺致主动脉收缩,IC₅₀为1.76×10^-5mol/L。提示MHDF对血管的作用与α受体阻断剂不同,而可能与钙拮抗有关。     

Status of risk factors and their consideration in antihypertensive therapy

Risk factors for cardiovascular disease include atherogenic personal attributes, living habits that promote them, signs of preclinical disease and host susceptibility. Atherogenic traits include the blood lipids, blood pressure and glucose tolerance. An increased low density lipoprotein cholesterol level is positively related, and an increased high density lipoprotein cholesterol level is inversely related, to cardiovascular disease incidence. Hypertension, whether systolic or diastolic, labile or fixed, casual or basal, at any age in either sex contributes greatly. The impact of diabetes is greater for women than men and varies depending on the level of the foregoing risk factors. An atherogenic lifestyle is typified by a diet excessive in calories, fat and salt, sedentary habits, unrestrained weight gain and smoking. Alcohol used in moderation may be beneficial. Oral contraceptives worsen atherogenic traits and, when used for long periods beyond age 35 and in conjunction with cigarettes, predispose to thromboembolism. Type A persons with an overdeveloped sense of time urgency, drive and competitiveness develop an excess of angina pectoris. Men married to more highly educated women are at increased risk as are men married to women in white collar jobs. Preclinical signs of compromised coronary circulation include silent myocardial infarction, left ventricular hypertrophy on the electrocardiogram, blocked intraventricular conduction and repolarization abnormalities. An electrocardiogram obtained during exercise may elicit still earlier evidence. Measures of innate susceptibility include a family history, history of premature cardiovascular disease, diabetes, hypertension and gout. Optimal prediction of risk requires a quantitative combination of risk factors in multiple logistic risk formulations to identify high risk persons with multiple marginal abnormalities.