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Biomedical subjects

J Wikstrand

Publications and source records attributed to J Wikstrand.

At least 91 records · Page 5Linked to original sources
PubMed1992

Increased systemic and renal vascular sensitivity to angiotensin II in normotensive men with positive family histories of hypertension.

Normotensive young men (mean age 36 years) with positive (PFH) (n = 13) and negative (n = 29) family histories of hypertension were investigated in order to study systemic and renal hemodynamics at baseline conditions and during infusion of low doses (0.1 and 0.5 ng/min/kg) of angiotensin II (AII). The control group with negative family histories of hypertension was subdivided into one group matched for body mass index (n = 15) to subjects with PFH, and one lean control group (n = 14). Baseline blood pressure and sodium intake, measured as urinary excretion, were higher in PFH and in matched controls than in the lean control group. At baseline, renal blood flow (para-aminohippurate clearance) did not differ significantly among the three groups, while glomerular filtration rate (inulin clearance) was higher in PFH than in matched controls. Both doses of angiotensin II infusion increased the blood pressure significantly in PFH. In matched controls a small increase in blood pressure was seen with the highest dose only, while no change in blood pressure was observed in the lean control group. In PFH both doses of AII infusion caused diminished renal blood flow (P less than .01) and increased renal vascular resistance (P less than .001). The two control groups remained unchanged with both AII doses. These results could indicate that normotensive subjects with positive family histories of hypertension are characterized by an increased sensitivity to AII in the systemic and renal circulation as compared with subjects with negative family histories of hypertension.

Adult↗
PubMed1992

Metoprolol-induced reduction in postinfarction mortality: pooled results from five double-blind randomized trials.

Several postinfarction trials have evaluated the effect of secondary prophylaxis with different beta-blockers. Although so called meta-analysis of the results from all the trials have shown a beneficial effect of postinfarction beta-blockade, many of the individual studies have shown inconclusive results, mainly due to low statistical power. In order to obtain an evaluation of the merits of postinfarction therapy with metoprolol, data from the five available studies with metoprolol have been pooled into one database. In the total material 5474 patients (4353 men, 1121 women) have been studied during double-blind therapy with metoprolol 100 mg twice daily or matching placebo. The follow-up ranges from 3 months to 3 years. In total 4732 patient years of observation have been obtained. In total there were 223 deaths in the placebo-treated patients as compared to 188 deaths in the metoprolol-treated patients (P = 0.036), which corresponds to mortality rates of 97.0 and 78.3 per 1000 patient years, respectively. The mortality reduction was found both in men and women. As has been reported from individual postinfarction beta-blocker trials, the pooled results showed a marked reduction in sudden deaths (104 in the placebo group, 62 in the metoprolol group, P = 0.002). In a Cox regression model the influence of sex, age and smoking habits on the effect of metoprolol was evaluated. None of these factors influenced the metoprolol effect significantly. It is concluded that metoprolol therapy after acute myocardial infarction reduces the total number of deaths, and especially sudden cardiac deaths. The mortality reduction was independent of gender, age and smoking habits. Available data support a continuous beneficial effect.

Double-Blind Method↗
PubMed1992

Reduced venous compliance in normotensive men with positive family histories of hypertension.

OBJECTIVE: To test the hypothesis of reduced venous compliance and increased cardiovascular responses to volume expansion and alpha-agonist stimulation. METHOD: Non-hypertensive healthy young men with positive (PFH) and negative family histories of hypertension were investigated regarding peripheral haemodynamics and changes in central venous pressure (CVP) and arterial blood pressure in response to graded doses of phenylephrine and acute i.v. fluid volume loading (1000 saline solution in 10 min). The control group was divided into one group matched for body mass index to PFH subjects (NFHO) and one lean control group (NFHN). RESULTS: Supine blood pressure was higher in PFH and NFHO subjects compared with NFHN subjects, whilst CVP was similar in the three groups at baseline. No significant differences in calf or forearm haemodynamics or blood volume were observed between the three groups. Cardiovascular responses to bolus doses of phenylephrine did not differ between the three groups. Saline infusion significantly increased CVP and systolic blood pressure, and effective vascular compliance (change in blood volume: CVP ratio) was reduced in PFH subjects. CONCLUSION: PFH subjects have decreased effective vascular compliance and altered arterial blood pressure responses to acute increases in vascular fluid volume. This may result from multiple factors such as increased venous vascular tone, structural reduction of venous distensibility and/or an altered neurohormonal response to increased CVP.

Adult↗
PubMed1992

Withdrawal of antihypertensive drug treatment: time-course for redevelopment of hypertension and effects upon left ventricular mass.

OBJECTIVES: To examine: (1) in how many treated hypertensive patients it was possible to discontinue drug treatment; (2) the time-course for redevelopment of hypertension after discontinuation of therapy; and (3) whether drug withdrawal was associated with an increase in left ventricular mass (LVM). DESIGN: Fifty-four men with primary hypertension treated for a mean period of 6 years (primarily beta 1-selective beta-blockade) were evaluated for withdrawal of treatment. Exclusion criteria were signs of organ damage, severe hypertension, other serious disease and unwillingness. Treatment was reinstituted if blood pressure increased above a safety level or if symptoms occurred. Echocardiographic estimations of LVM were obtained before withdrawal and 1, 4 and 8 weeks after withdrawal or before return to treatment. SETTING: Outpatient clinic in a city hospital. PATIENTS: A random sample of 56-year-old hypertensive men. INTERVENTION: Gradual discontinuation of treatment with close follow-up of blood pressure. MAIN OUTCOME MEASURES: Number of patients who could withdraw from treatment and who had to return to pharmacological therapy; time-courses for development of hypertension; absolute changes in LVM. RESULTS: Thirty-two patients withdrew from treatment for 1-1000 days. Therapy was reinstituted in all owing to hypertension or symptoms. Serial echocardiograms were obtained in 22 patients. During the drug-free period, relative wall thickness increased, but LVM did not. Patients with rapid redevelopment of hypertension had larger prewithdrawal LVM than patients whose blood pressure increased more slowly. CONCLUSION: It was possible to withdraw treatment and obtain readable echocardiograms in a minority of the patients. After drug-withdrawal, relative wall thickness increased, but not LVM. We suggest that previously treated patients should be avoided in studies examining reversal of left ventricular hypertrophy.

Antihypertensive Agents↗
PubMed1992

Reducing the risk for coronary heart disease and stroke in hypertensives--comments on mechanisms for coronary protection and quality of life.

The four most popular classes of antihypertensive drugs may all be considered suitable choices when initiating treatment for hypertension. The practitioner must decide which agent is appropriate for each individual patient. The main goal of treatment should be to prevent coronary events and stroke, while preserving quality of life. A 40% reduction in stroke can probably be achieved with any antihypertensive treatment, a reduction in coronary events is much harder to achieve. Available evidence from studies in men, summarized in this review, indicates that beta-blockade is superior to thiazide diuretics for the prevention of coronary events. Clinical trials have not yet produced long-term prognostic data on the effects of ACE-inhibitors or calcium antagonists on coronary events in hypertensive patients. A recent review on calcium antagonists in post-MI patients concluded that the results were disappointing, as pooled data actually showed a trend towards increased mortality with calcium antagonists as compared with placebo. Because of the large number of hypertensive patients at increased risk for coronary events in the community, the difference observed in coronary events between beta-blockade and other first-line drugs in hypertension (24%) may have important implications for clinical practice. This overall conclusion, however, has to be accepted with some reservations in view of the following observations. Firstly, no reduction in sudden death has been observed with the hydrophilic beta-blockers. Secondly, no reduction in coronary mortality in the smoking subgroup has been observed with the non-selective beta-blockers. Thus, it seems that the prevention of coronary events is more likely to be observed in patients given beta-blockers with certain pharmacological characteristics: relative lipophilicity, which enables passage of the beta-blocker through the blood-brain barrier to exert effects on pertinent central nervous beta 1-receptors. This is potentially useful in reducing the risk of sudden death. The addition of beta 1-selectivity is important for the risk reduction in smokers. Cardioselectivity is also an advantage in relation to side-effects and quality of life. The reduced risk for coronary events with certain beta-blockers is probably independent of the reduction in blood pressure: possible mechanisms studied are cardiac anti-ischaemic effects, antifibrillatory effects, antiatherosclerotic and anti-thrombotic effects.

Cerebrovascular Disorders↗
PubMed1992

Arterial wall thickness in familial hypercholesterolemia. Ultrasound measurement of intima-media thickness in the common carotid artery.

B-mode ultrasound was used to noninvasively determine wall thickness and lumen diameter in the common carotid artery in patients with familial hypercholesterolemia (n = 53) and in a control group (n = 53). The controls were matched for sex, age, height, and weight, and all had a serum cholesterol level below 6.5 mmol/l. The study was performed to evaluate whether the patients had a thicker arterial wall compared with that of the control group. Wall thickness was determined as the combined intima-media thickness of the far wall and is presented as the mean and maximum thickness of a 10-mm-long section of the common carotid artery. The difference between the groups was 0.13 mm in mean wall thickness (p less than 0.001; 95% confidence interval, 0.07-0.18 mm) and 0.20 mm in maximum wall thickness (p less than 0.001; 95% confidence interval, 0.09-0.23 mm). Fifty of the subjects were examined twice to estimate the interobserver variability. The coefficients of variation for mean and maximum wall thickness were 10.2% and 8.9%, respectively. The two study groups were well matched and differed only in lipid levels. Thus, there is reason to believe that the difference in wall thickness can be explained by the background of familial hypercholesterolemia and the increased cholesterol levels.

Adult↗
PubMed1992

Noninvasive quantification of atherosclerotic lesions. Reproducibility of ultrasonographic measurement of arterial wall thickness and plaque size.

A noninvasive method based on high-resolution B-mode ultrasonography and a computerized image-analyzing system were used for the quantification of early (thickening of the intima-media complex) and late (plaque) atherosclerosis in the carotid and the femoral artery. The difference between repeated measurements was assessed to estimate intraobserver and interobserver differences. The results were satisfactory, with a coefficient of variation for measurement of lumen diameter in the common carotid artery of 3.8 +/- 4.1% (r = 0.91) and for the femoral artery of 4.8 +/- 4.1% (r = 0.93). Corresponding figures for intima-media thickness in the common carotid artery and the femoral artery were 10.0 +/- 8.5% (r = 0.86) and 16.2 +/- 12.6% (r = 0.91), respectively. The coefficient of variation for measurements of maximal intima-media thickness at the site of the plaque was 14.6 +/- 10.5% (r = 0.88); for plaque base, 13.1 +/- 9.0% (r = 0.91); and for plaque area, 16.3 +/- 12.6% (r = 0.90). The method seems promising for the detection and quantification of early and late atherosclerotic lesions in the carotid and femoral arteries.

Aged↗
PubMed1992

Increased waist/hip ratio, metabolic disturbances, and family history of hypertension.

To test whether nonhypertensive subjects with a two-generation positive family history of hypertension (PFH) are characterized by disturbed glucose metabolism, 16 men (38 +/- 6 years old) with PFH and 25 subjects matched for age and with negative family histories of hypertension (NFH) were recruited. Blood pressure; serum lipids; erythrocyte transmembrane sodium transport; and the glucose, plasma insulin, and C-peptide responses to an oral glucose tolerance test were investigated. Subjects with PFH had higher blood pressure, body weight, body mass index (BMI), waist/hip ratio (WHR), and abdominal sagittal diameter than subjects with NFH. Baseline blood glucose, plasma insulin, serum lipids, and transmembrane sodium transport did not differ between the two groups. Blood glucose levels at 90 and 120 minutes after oral glucose were significantly higher in subjects with PFH than in controls. Blood glucose adjusted for BMI and WHR at 90 minutes was significantly related to a PFH. Plasma insulin level at 90 minutes during the glucose load was significantly higher in subjects with PFH. In multivariate analysis, WHR was significantly related to baseline blood pressure, insulin, and cholesterol, whereas BMI was significantly associated with the insulin response to the oral glucose tolerance test. Transmembrane sodium transport was significantly related to blood pressure only. In conclusion, subjects with PFH are characterized by increased body weight and BMI, increased visceral fat accumulation, and an altered blood glucose response to an oral glucose load. It was also shown that WHR was related to blood pressure and that BMI was more related to cholesterol and response to glucose loading than a PFH was.

Adult↗
PubMed1992

Increased response to physical and mental stress in men with hypertensive parents.

Blood pressure and heart rate responses to isometric handgrip exercise were studied at age 31 and after 5 years in young nonhypertensive men with positive family histories of hypertension (n = 13) and in those with negative family histories of hypertension (n = 13) for two generations to test whether subjects with positive family histories established a pattern of increased blood pressure and heart rate responses during the 5-year follow-up period. At follow-up the response to mental stress (Stroop's color word test) was also studied. Baseline blood pressure and heart rate at rest did not differ, initially or at follow-up, between the groups. At the initial examination, absolute blood pressure levels were significantly higher during isometric handgrip exercise just before exhaustion in subjects with positive family histories. At follow-up the absolute blood pressure level (p < 0.001) and the blood pressure responses (p < 0.01-0.001) were found to be significantly increased during handgrip exercise in subjects with positive family histories compared with subjects with negative family histories. In subjects with positive family histories the diastolic blood pressure response was significantly higher (p < 0.01) at follow-up than initially and was significantly related (r = 0.70, p < 0.01) to changes in baseline diastolic blood pressure during the follow-up period. In subjects with negative family histories the systolic blood pressure response was somewhat lower at follow-up than initially. During the mental stress test, the blood pressure response was significantly greater in subjects with positive than with negative family histories.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The role of beta receptor blockade in preventing sudden death.

The high mortality rate from coronary heart disease in hypertensives can only be substantially reduced if sudden coronary death rates can be decreased. The aim of this review is to discuss how treatment may be tailored to reduce the risk of sudden death in high-risk patients. Clinical trials have not yet produced long-term primary prevention data on the effects of angiotensin converting enzyme (ACE) inhibitors, calcium antagonists or alpha-blockers on cardiovascular complications and sudden death in hypertensive patients. Further, the conclusion from large-scale secondary preventive studies presently available on ACE inhibitors and calcium antagonists is that their impact on sudden death has been disappointing. By contrast, some beta-blockers have reduced sudden death and other coronary events both in primary and secondary preventive studies. The benefits have been attributed to beta 1-blockade, and seem to be independent of blood pressure control. It cannot be assumed that all beta-blockers are equally effective in preventing ventricular fibrillation, sudden death and other coronary events. To date, the best documented data cover the lipophilic beta-blockers and it is speculated that by increasing levels of cardiac vagal tone and electrical stability in the heart, beta 1-blockade in the brain might contribute to the reduction in sudden death risk seen with these beta-blockers.

Adrenergic beta-Antagonists↗
PubMed1991

Blunted renal sodium excretion during acute saline loading in normotensive men with positive family histories of hypertension.

The natriuretic and intra-arterial blood pressure response to an acute saline load (1000 mL 0.9% NaCl), was studied in normotensive young men with positive (n = 11) and negative (n = 21) family histories of hypertension. The age-matched (36 +/- 5 years) control group with negative family histories of hypertension was subdivided into two groups, one matched for body mass index (BMI) to the subjects with positive family histories of hypertension (n = 10), and another lean control group (n = 11). Baseline blood pressure was significantly higher in subjects with positive family histories of hypertension and in controls matched for BMI as compared with lean controls. Sodium excretion increased in all three groups during the saline infusion, while subjects with positive family histories of hypertension disclosed a diminished natriuretic response as compared with the two control groups. Systolic blood pressure increased significantly during the saline load in subjects with positive family histories of hypertension, while in subjects with negative family histories of hypertension, no significant change in blood pressure was observed. Plasma renin activity, angiotensin II, serum aldosterone, plasma noradrenaline, blood volume, and ouabain-sensitive erythrocyte sodium efflux rate constant did not differ between the three groups at baseline. A significant negative correlation was found between baseline sodium excretion and sodium efflux rate constant in subjects with positive family histories of hypertension. We conclude that the subjects with positive family histories of hypertension exhibit a blunted natriuretic and an exaggerated blood pressure response to an acute saline load as compared with the two control groups with negative family histories of hypertension. This could be of neuronal and/or hormonal origin.

Adult↗
PubMed1991

Resting and volume-stimulated circulating atrial natriuretic peptide in young normotensive men with positive family histories of hypertension.

Normotensive young men (36 +/- 5 years old) with positive family histories of hypertension (n = 11) and age-matched controls (n = 21) with negative family histories of hypertension were examined. The control group was divided into one group matched for body mass index with those subjects with positive family histories (n = 10) and one group with normal body mass index (n = 11). Blood pressure, central venous pressure (CVP), plasma atrial natriuretic peptide (ANP) and serum aldosterone were examined at a baseline and during an acute volume load with 1000 ml saline solution. Subjects with positive family histories and controls matched for body mass index had a higher blood pressure at baseline than controls with normal body mass index. CVP and serum aldosterone did not differ between the three groups, while sodium intake and plasma concentrations of ANP were significantly higher in subjects with positive family histories. During volume loading, CVP increased significantly more in subjects with positive family histories as compared with the two control groups. A blunted response to ANP was observed during volume loading in subjects with positive family histories, while subjects in the two control groups demonstrated comparable and significant increases in circulating ANP. Serum aldosterone, however, decreased during volume loading in all three groups, with no difference between the groups. We conclude that normotensive subjects with positive family histories are characterized by increased basal concentrations of ANP and exhibit a blunted response to an acute volume load.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Cardiovascular effects of weight reduction versus antihypertensive drug treatment: a comparative, randomized, 1-year study of obese men with mild hypertension.

The aim of the study was to compare cardiovascular effects of weight reduction and sodium restriction with antihypertensive drug treatment in obese middle-aged men with mild hypertension in an open randomized trial lasting for 1 year, preceded by a 6-week run-in period. In the diet group (n = 31), weight decreased by 7.8 kg and salt intake by 2 g/day. In the other group (n = 30), treatment was structured with atenolol as the first line drug. The differences in antihypertensive response were highly significant when measured as casual blood pressure, with drug treatment being favoured. Echocardiographic estimations of left ventricular morphology and function showed no difference in effects between the two treatment modalities. Further analyses showed that the presence of previous antihypertensive treatment was modulating the effect of intervention on left ventricular mass. The response to treatment in plethysmographic estimations of resistance at maximal dilatation in the forearm did not differ between the groups. We conclude that drug treatment was superior to the diet regimen in controlling hypertension, that no differences were observed in effects on cardiovascular structure and that previous antihypertensive treatments seems to be a potent confounding factor that should be taken into consideration in future studies.

Adult↗
PubMed1991

Normotensive young men with family histories of hypertension gain weight and decrease their intraerythrocyte sodium content during a 5-year follow-up.

Young normotensive men matched for age and body mass index with (n = 16) and without (n = 13) family histories of hypertension were investigated at baseline and after 5 years of follow-up with respect to blood pressure, body weight and intracellular sodium content. Subjects with positive family histories of hypertension increased significantly in body weight (from 81.9 +/- 11.5 kg to 89.5 +/- 11.4 kg, P less than 0.001) compared to subjects with negative family histories of hypertension (from 79.9 +/- 10.8 kg to 80.7 +/- 12.2 kg, NS). Their blood pressure did not differ initially (137 +/- 12/75 +/- 11 mmHg vs. 135 +/- 8/72 +/- 9 mmHg), but was reduced in subjects without family histories of hypertension (to 125 +/- 3/68 +/- 13 mmHg) in the follow-up examination. At follow-up, body mass index showed a positive correlation with blood pressure among subjects with positive family histories of hypertension (r = 0.77, P less than 0.001). At baseline, subjects with hypertensive fathers had significantly higher intraerythrocyte sodium levels than subjects with normotensive parents. At re-examination 5 years later, this difference was no longer present. We conclude that normotensive subjects with positive family histories of hypertension are predisposed to gain weight rather than to show an increase in blood pressure at this age. Normalization of intracellular sodium content, as found in the present study, could be a consequence of this weight gain and the ensuing metabolic adaption.

Adult↗
PubMed1991

Ultrasound measurement of wall thickness in the carotid artery: fundamental principles and description of a computerized analysing system.

A B-mode [two-dimensional (2D)] image from the carotid artery may be described as containing seven echo zones. The aim of the present work is to discuss how lumen diameter and wall thickness can be measured from these zones, and to review some of the basic principles of ultrasound physics and imaging. Simple experiments were performed to identify the echoes defining intima-lumen interfaces. The results showed that: (1) The intima-media thickness of the near wall cannot be measured in a valid way. (2) The lumen diameter of a blood vessel is defined by the distance from the leading edge of the intima-lumen interface of the near wall (echo zone 3) to the leading edge of the lumen-intima interface of the fall wall (echo zone 5). (3) Previously published studies have validated the intima-media complex of the far wall as the distance from the leading edge of the lumen-intima interface of the far wall to the leading edge of the media-adventitia interface of the far wall (echo zone 7). We suggest that if measurements on the near wall are performed, measurements from the far wall should also be presented separately, and if lumen diameter is measured, that this measurement is carried out according to the leading edge principle. We describe a computerized analysing system for the measurement of wall thickness and plaque area on the carotid and femoral arteries. The system is based on a low-cost PC and a frame grabber board and calculates minimum, maximum and mean values of lumen diameter and wall thickness from a section of the artery.

Carotid Arteries↗
PubMed1991

Metoprolol versus thiazide diuretics in hypertension. Morbidity results from the MAPHY Study.

The present study in hypertensive men (40-64 years old) with untreated diastolic blood pressure above 100 mm Hg was aimed at investigating whether metoprolol (n = 1,609) given as initial treatment would lower the risk for coronary events (sudden death and myocardial infarction) more effectively than thiazide diuretics (n = 1,625). A substantial part of this study was the metoprolol arm of the Heart Attack Primary Prevention in Hypertension (HAPPHY) study. The HAPPHY study was a pooling of the effect of different beta-blockers, mainly metoprolol and atenolol, in which no favorable effect in relative risk was observed for atenolol as compared with diuretics. In the present study, 255 patients suffered definite coronary events during follow-up; 25% of these events were fatal, 39% were acute myocardial infarctions, and 36% were silent myocardial infarctions. The risk for coronary events was significantly lower in patients on metoprolol than in patients on diuretics (111 versus 144 cases, p = 0.001, corresponding to 14.3 versus 18.8 cases/1,000 patient years and a relative risk of 0.76 at the end of the trial; 95% confidence interval 0.58-0.98). This difference in risk has potentially important implications for clinical practice because of the large number of hypertensive patients who are at increased risk for coronary events. Because a placebo group, for ethical reasons, could not be included, relative risk can only be expressed in relation to diuretics. There was no difference between the two treatment groups in baseline characteristics, blood pressure during follow-up, or stroke rates. Thus, the difference in risk for coronary events is probably mediated via mechanisms other than blood pressure control. However, present data might suggest that different beta-blockers may have different efficacy in preventing coronary events. The reasons for this possibility are as yet unknown.

Adult↗