Blood pressure and mortality in elderly people.
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Aged↗
Biomedical subjects
J M Cruickshank
Publications and source records attributed to J M Cruickshank.
The beta 1 hyperselectivity in beta-blocker treatment.
Coronary heart disease (CHD) is the most common cause of death in Western industrialized countries. CHD is more common in individuals with clustering of coronary risk factors, e.g., hypertension and blood lipid abnormalities. There is a good rationale for the use of beta-blockers for prevention of myocardial infarction (MI) in high-risk groups, as beta-blockade decreases myocardial oxygen consumption and, by decreasing turbulent blood flow patterns, reduces endothelial shear forces, thus making plaque rupture (and the ensuing thrombotic events) less likely. Clinical trial data have shown beta-blockade to be effective in the prevention of cardiovascular end points. In both younger and older hypertensive patients there is a significant reduction in the incidence of stroke and in younger hypertensive patients there is about a 15% reduction in MI. Left ventricular hypertrophy (particularly by ECG) is significantly diminished. In secondary prevention of MI there is about 15% reduction after early and 25-30% reduction after late intervention with beta-blockers given post-MI. In both stable and unstable angina, beta-blockade appears to be beneficial not only in improvement of symptoms but also in prevention of hard cardiovascular end points. There are also promising data suggesting that beta-blockade is useful in endothelial protection and atheroma prevention, and benefits patients with hypertrophic cardiomyopathy and heart failure. beta-Blockers have evolved from early nonselective agents, e.g., propranolol, to modern highly beta 1-selective agents, e.g., bisoprolol. beta 1-Blockade is the essential element that leads to the above cardiovascular benefits in addition to improving the quality of life (similar to angiotensin-converting enzyme inhibitors).
Adrenergic beta-1 Receptor Antagonists↗
Relation between aortic atherosclerosis and blood pressure.
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Aorta, Abdominal↗
J curve in antihypertensive therapy--does it exist? A personal point of view.
Coronary flow is maintained in the face of changing perfusion pressure (approximates to diastolic blood pressure [DBP]) by the process of autoregulation. A normal coronary artery is able to dilate fivefold (coronary flow reserve of 5); by contrast, coronary flow reserve falls in the presence of left ventricular hypertrophy [LVH] and/or coronary artery disease. Thus a fall in DBP that is normally well tolerated causes a fall in coronary flow, ECG changes, and left ventricular dysfunction in the presence of LVH and coronary artery disease. Such high-risk patients exhibit a J-curve relationship between DBP and death from coronary artery disease; lowering DBP (phase 5) to below the mid 80s would be imprudent in such patients.
Administration, Oral↗
Accuracy of the Omron HEM 706 portable monitor for home measurement of blood pressure.
A reliable, well-validated home blood pressure (BP) self-measurement device could have an important role in the management of hypertension by the early identification of 'white coat' hypertensives. Under rigorous assessment such devices have not performed well in the estimation of DBP, particularly in the hypertensive range. We assessed the Omron HEM 706 device (oscillometric) for home measurement of BP according to the standards set out by the British Hypertension Society protocol and the Association for the Advancement of Medical Instrumentation (AAMI). The device was compared with simultaneous measurements made by two 'blinded' observers using a standard mercury sphygmomanometer in the same arm in 85 subjects aged 17-76 years with a wide range of BPs. The device was satisfactory over the whole BP range (SBP 89-188 mmHg, DBP 44-118 mmHg), with a B grading for SBP and a C grading for DBP (British Hypertension Society protocol) and a PASS for both SBP and DBP (AAMI). For the diastolic hypertensive range 90-120 mmHg, where most clinical decisions are made, the device scored a B grade for SBP and an A grade for DBP, with a PASS for both SBP and DBP. We conclude the Omron HEM 706 device for home BP measurement is highly satisfactory, particularly in the mild to moderate hypertension range, and is suitable for clinical use.
Adolescent↗
How far to lower blood pressure.
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Blood Pressure↗
Treatment of hypertension in older adults.
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Adrenergic beta-Antagonists↗
The J curve lives.
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Antihypertensive Agents↗
Remodeling and reparation of the cardiovascular system.
Growth or altered metabolism of nonmyocyte cells (cardiac fibroblasts, vascular smooth muscle and endothelial cells) alters myocardial and vascular structure (remodeling) and function. However, the precise roles of circulating and locally generated factors such as angiotensin II, aldosterone and endothelin that regulate growth and metabolism of nonmyocyte cells have yet to be fully elucidated. Trials of pharmacologic therapy aimed at preventing structural remodeling and repairing altered myocardial structure to or toward normal in the setting of hypertension, heart failure and diabetes are reviewed. It is proposed that these are therapeutic goals that may reduce cardiovascular morbidity and mortality. Although this hypothesis remains unproved the primary goal of therapy should be to preserve or restore tissue structure and function.
Animals↗
The role of coronary perfusion pressure.
Coronary flow is normally autoregulated so that within wide limits of changes in perfusion pressure (which approximate to diastolic BP) blood flow to the heart remains constant. Thus, as perfusion pressure falls, the coronary arterioles dilate to maintain flow; under basal conditions a five-fold increase in coronary flow can occur, i.e. a flow reserve of five. Coronary flow reserve is markedly impaired in the presence of severe coronary artery stenosis and/or LVH. In the presence of severe stenosis and LVH a fall in perfusion pressure (DBP), which would be normally well tolerated, results in a fall of coronary flow, ECG changes and ventricular dysfunction (fall in ejection fraction instead of the usual increase). The above mechanisms underlie the J-curve relationship between DBP and myocardial infarction (MI) in high risk hypertensives. In the absence of overt coronary artery disease (CAD) and LVH, the lower the DBP the better. However in the presence of CAD and LVH lowering the DBP (phase 5) to below the low-mid 80s results in an increased frequency of MI.
Blood Pressure↗
Beta-blockers: primary and secondary prevention.
Coronary heart disease is the most frequent cause of death in Western, industrialized countries. Coronary risk factors are prevalent in such countries and sometimes combine to constitute the so-called syndrome X--hypertension, central obesity, serum lipid and clotting disturbances, and insulin resistance. beta-Blockers, unlike calcium antagonists, have proved highly effective in secondary prevention of myocardial infarction. If present at the time of the myocardial infarction, beta-blockers (unlike calcium antagonists and diuretics) probably decrease mortality 1 month later. Early intervention (within 12 h) of chest pain with intravenous beta-blockers results in a 15% reduction in cardiovascular mortality at 1 week. Later intervention (3-28 days) with oral non-ISA beta-blockers results in a 30% reduction in mortality after 1 year; ISA-containing beta-blockers are probably less effective (less decrease in heart rate). Hydrophilicity/lipophilicity of beta-blockers is unimportant in terms of decreased mortality. Primary prevention of myocardial infarction, unlike stroke, in hypertensive patients has been disappointing, possibly due to treatment-induced biochemical/lipid changes or inappropriate lowering of diastolic blood pressure in high-risk subjects (J-curve effect). beta-Blockers should be first-line therapy for hypertensive patients up to the age of 65 years, particularly men (and nonsmokers) as Q-wave myocardial infarction is significantly decreased by beta-blockers and significantly increased by diuretics. However, in elderly hypertensive subjects, beta-blockers have not significantly decreased myocardial infarction (unlike stroke), whereas diuretics have. The effects of beta-blockers and diuretics on heart size (and thus coronary flow reserve) in the elderly may be important. Thus, beta-blockers should be second-line therapy for the elderly hypertensive individual but first-line if overt ischemia (e.g., angina or recent myocardial infarction) also is present. In patients with angina but normal blood pressure, beta-blockers tend to decrease and calcium antagonists increase cardiovascular events. Thus, beta-blockers are highly effective agents in the secondary prevention of myocardial infarction and are moderately effective in primary prevention of myocardial infarction in hypertensive patients (particularly men) under the age of 65 years.
Adrenergic beta-Antagonists↗
Clinical importance of coronary perfusion pressure in the hypertensive patient with left ventricular hypertrophy.
In patients with severe left ventricular hypertrophy (LVH), but no significant coronary artery disease (CAD), acute lowering of diastolic blood pressure (DBP) to less than 85 mm Hg is reported to result in a 26% fall in coronary blood flow and an increase in myocardial oxygen demand; S-T segment and T-wave changes in the ECG are observed when DBP is acutely lowered to the 70s in these patients. In the presence of good resting left ventricular function, acute lowering of DBP to the 60s in well-controlled hypertensives on a beta-blocker, with either CAD or LVH, results in a mean increase of about 20% in ventricular ejection fraction. By contrast, patients with a combination of CAD and LVH experience a mean 6% fall in ejection fraction implying poor left ventricular functional reserve. In low risk populations, which exclude patients with severe ischaemia, diabetics and smokers, the lower the DBP the fewer the number of myocardial infarctions. However, in heterogeneous hypertensive populations which include high risk patients, such as ischaemics and diabetics (e.g. the MRFIT population), there is a strong U- or J-curve relationship between DBP and CAD deaths. Meta-analysis of high quality studies involving heterogeneous populations has shown that the U- or J-point is at 84 mm Hg and probably relates to high risk patients with ischaemia and/or LVH. Recent data from the Framingham group indicate that the patients most at risk are those with a combination of CAD and LVH: these patients showed a marked U-shaped curve with the U- or J-point at about 85-89 mm Hg DBP.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Reversibility of left ventricular hypertrophy.
Left ventricular hypertrophy (LVH) is a powerful independent risk factor for coronary artery disease. This overview of 104 studies examines the ability of various types of antihypertensive therapies to reverse LVH as assessed by echocardiography. Combination therapy, angiotensin converting enzyme (ACE) inhibitors, and methyldopa were the most effective in reversing LV mass; vasodilators such as minoxidil and hydralazine had no effect on LVH. These differences were independent of the degree of fall in blood pressure and duration of therapy. beta-blockers were as effective as ACE inhibitors in decreasing LV wall thickness. Possible reasons for drug differences in reversing LVH are discussed. Preliminary evidence suggests that reversing LVH by antihypertensive drug therapy is associated with a reduction in cardiovascular complications.
Antihypertensive Agents↗
The case for beta-blockers as first-line antihypertensive therapy.
REASON FOR TREATMENT: In patients with asymptomatic high blood pressure, antihypertensive treatment is initiated for only one reason, to prevent the hypertensive sequelae of myocardial infarction, stroke and heart failure. MORBIDITY, MORTALITY AND SURROGATE ENDPOINTS: Only diuretics and beta-blockers have been shown to benefit hypertensive patients in terms of the hard endpoints morbidity and mortality. beta-Blockers and diuretics are cheaper than newer drugs and thus represent good value for money. It is not acceptable to use drug effects on plasma lipids or insulin resistance as measures of the effects on coronary heart disease, since dihydropyridine calcium antagonists improve these parameters while significantly increasing coronary heart disease events in the acute and chronic ischaemic situation. PATIENT PROFILING: Diuretics. Diuretics appear particularly suited to elderly hypertensives, especially those with isolated systolic hypertension, but they may increase cardiac events in younger and middle-aged diabetic and non-diabetic hypertensives. Angiotensin converting enzyme (ACE) inhibitors. ACE inhibitors are undoubtedly valuable in the presence of left ventricular dysfunction, and possibly in the diabetic in maintaining good renal function. beta-Blockers. beta-Blockers are particularly well suited to younger and middle-aged hypertensives at all blood pressure levels, especially white males; where ischaemia and/or stress is a factor, beta-blockers can significantly reduce the incidence of myocardial infarction and strokes. beta-Blockers benefit elderly hypertensives by preventing strokes and may prevent coronary heart disease if prescribed with a diuretic.
Adrenergic alpha-Antagonists↗
Antihypertensive drugs and cardioprotection.
Cardioprotection is a broad term; this short review deals with six aspects: 1. Secondary prevention of myocardial infarction (MI) has been shown for beta-blockers in both early and late intervention studies. Dihydropyridine calcium antagonists are associated with an excess incidence of coronary events, whereas non-dihydropyridines prevent reinfarction provided left ventricular (LV) function is adequate; dihydropyridines tend to increase heart rate and stimulate the sympathetic and renin-angiotensin systems. 2. Primary prevention of MI has been shown for beta-blockers in younger/middle-aged hypertensives but not in the elderly. Diuretics, by contrast, possibly increase the risk of coronary events in younger/middle-aged hypertensives but significantly reduce coronary events in older hypertensives. These results might be explained by the larger, noncompliant left ventricle of the elderly hypertensive, which, in the absence of overt ischemia, responds poorly to beta-blockade (further enlargement with increased wall stress and impaired coronary reserve), while diuretics have the opposite effect. Primary prevention of coronary events in patients with chronic angina is likely to occur with beta-blockers, while studies with calcium antagonists have shown a significant excess of coronary events. 3. Ischemic events occurring during the "vulnerable" period between 7 and 10 AM (when sympathetic activity is maximal) are significantly reduced by beta-blockers but not by calcium antagonists. 4. Stress-induced myocardial necrosis in humans is markedly reduced by beta-blockers. 5. Coronary risk factors, such as elevated blood lipids, hyperglycemia, and insulin resistance, are possibly adversely affected by diuretics and beta-blockers, with the former also increasing heart rate, plasma renin activity, and plasma catecholamine levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Adrenergic beta-Antagonists↗
Do we need more beta-blockers?
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Adrenergic beta-Antagonists↗
Reversibility of left ventricular hypertrophy by differing types of antihypertensive therapy.
Left ventricular hypertrophy (LVH), as assessed by ECG or echocardiography, is a powerful independent coronary risk factor. The present overview of 104 studies sets out to compare the ability of various forms of antihypertensive therapy to reverse LVH as assessed by echocardiography. Most observations involved four classes of treatment--combination therapy, ACE inhibitors, beta-blockers and calcium antagonists (mainly dihydropyridines). The former two therapies were significantly more effective than the latter two in reversing LV mass, independently of length of time on treatment and degree of fall in blood pressure. Possible reasons for these differences are discussed. The clinical significance of these results is unclear although preliminary data indicate that regressing LVH is associated with fewer cardiovascular events.
Antihypertensive Agents↗
Relation of low diastolic blood pressure to coronary heart disease death in presence of myocardial infarction: the Framingham Study.
OBJECTIVE: To examine the hypothesis that a J curve relation between blood pressure and death from coronary heart disease is confined to high risk subjects with myocardial infarction. DESIGN: Cohort longitudinal epidemiological study with biennial examinations since 1950. SETTING: Framingham, Massachusetts, USA. SUBJECTS: 5209 subjects in the Framingham study cohort followed up by a person examination approach. MAIN OUTCOME MEASURES: Coronary heart disease deaths and non-cardiovascular disease deaths in men and women with or without myocardial infarction relative to blood pressure. RESULTS: Among subjects without myocardial infarction non-cardiovascular disease deaths were twice to three times as common as coronary heart disease deaths. Furthermore, there was no significant relation between non-cardiovascular disease death and diastolic or systolic blood pressure. Also coronary heart disease deaths were linearly related to diastolic and systolic blood pressures. Among high risk patients (that is, people with myocardial infarction but free of congestive heart failure) death from coronary heart disease was more common than non-cardiovascular disease death. There was a significant U shaped relation between coronary heart disease death and diastolic blood pressure. Although there was an apparent U shaped relation between coronary heart disease death and systolic blood pressure, it did not attain statistical significance when controlling for age and change in systolic blood pressure from the pre-myocardial infarction level. None of the above conclusions changed when adjustments were made for risk factors such as serum cholesterol concentration, antihypertensive treatment, and left ventricular function. The U shaped relation between diastolic blood pressure and high risk subjects existed for both those given antihypertensive treatment and those not. CONCLUSIONS: These data suggest that an age and sex independent U curve relation exists for diastolic blood pressure and coronary heart disease deaths in patients with myocardial infarction but not for low risk subjects without myocardial infarction. The relation seems to be independent of left ventricular function and antihypertensive treatment.
Adult↗