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Biomedical subjects

J Blacher

Publications and source records attributed to J Blacher.

At least 19 recordsLinked to original sources
PubMed2000

Pulse pressure not mean pressure determines cardiovascular risk in older hypertensive patients.

BACKGROUND: Current guidelines for the management of hypertension rest almost completely on the measurement of systolic and diastolic blood pressure. However, the arterial blood pressure wave is more correctly described as consisting of a pulsatile (pulse pressure) and a steady (mean pressure) component. OBJECTIVE: To explore the independent roles of pulse pressure and mean pressure as determinants of cardiovascular prognosis in older hypertensive patients. METHODS: This meta-analysis, based on individual patient data, pooled the results of the European Working Party on High Blood Pressure in the Elderly trial (n = 840), the Systolic Hypertension in Europe Trial (n = 4695), and the Systolic Hypertension in China Trial (n = 2394). The relative hazard rates associated with pulse pressure and mean pressure were calculated using Cox regression analysis, with stratification for the 3 trials and with adjustments for sex, age, previous cardiovascular complications, smoking, and treatment group. RESULTS: A 10-mm Hg wider pulse pressure increased the risk of major cardiovascular complications; after controlling for mean pressure and the other covariates, the increase in risk ranged from approximately 13% for all coronary end points (P = .02) to nearly 20% for cardiovascular mortality (P = .001). In a similar analysis, mean pressure predicted the incidence of cardiovascular complications but only after removal of pulse pressure as an explanatory variable from the model. Furthermore, the probability of a major cardiovascular end point increased with higher systolic blood pressure; at any given level of systolic blood pressure, it also increased with lower diastolic blood pressure, suggesting that the wider pulse pressure was driving the risk of major complications. CONCLUSIONS: In older hypertensive patients, pulse pressure not mean pressure is the major determinant of cardiovascular risk. The implications of these findings for the management of hypertensive patients should be further investigated in randomized controlled outcome trials in which the pulsatile component of blood pressure is differently affected by antihypertensive drug treatment.

Aged↗
PubMed2000

[Current recommendations on arterial hypertension and its therapy. A critical analysis].

OBJECTIVE: The purpose of this editorial is to give a critical view of recommendations recently published on hypertension. ANALYSIS: Present changes in therapeutic aspects involving both pharmacological and non pharmacological treatment are analyzed together with the development of new compounds. CONCLUSION: It is suggested that the organization of care, more than the discovery of new compounds is the critical point for improvement of cardiovascular risk in hypertension.

Antihypertensive Agents↗
PubMed2000

Spontaneous renal artery dissection revealed by helical CT angiography.

Spontaneous renal artery dissection is rare and may be misdiagnosed because its clinical presentation is confusing. Diagnosis is usually made by intra-arterial angiography. We report a case where a spontaneous renal artery dissection was initially misdiagnosed as a renal abscess. Diagnosis was made later with helical CT for suspicion of renal artery stenosis in a patient with recent onset of hypertension. This unusual case shows that helical CT can be useful for non-invasive diagnosis of renal artery dissection.

Abscess↗
PubMed2000

Assessment of vascular aging and atherosclerosis in hypertensive subjects: second derivative of photoplethysmogram versus pulse wave velocity.

The pulse wave velocity (PWV) and the photoplethysmogram (PTG) are noninvasive methods for evaluating the pulse wave. The PWV has been associated with age and arterial hypertension, and an index of the second derivative of PTG (SDPTG) is correlated with age and other risk factors for atherosclerosis. The aim of this study was to compare SDPTG and PWV concerning the influencing factors of vascular compliance, including age and atherosclerosis, in a large hypertensive population. We studied consecutively 524 essential hypertensives, 140 with atherosclerotic alterations (AA), defined on the basis of clinical events including coronary heart disease, peripheral vascular disease, stroke, and abdominal aorta aneurysm. The PWV carotid-femoral was measured by a Complior device and the SDPTG was recorded by Fukuda FCP-3166. The augmentation index (AUI) of PTG was defined as the ratio of the late systolic peak to that of the early systolic peak in the pulse. The SDPTG consists of an a,b,c, and d wave in systole and an e wave in diastole; an SDPTG aging index (AI) was calculated as (b-c-d-e)/a. The patients with AA presented a higher PWV (14.9 +/- 4 m/sec v 12.4 +/- 2 m/sec, P < .001), PTG AUI (0.322 +/- 0.16 v 0.252 +/-0.09, P < .001), and SDPTG AI (-0.093 +/- 0.03 v -0.271 +/- 0.018, P < .001). However, in patients 60 years of age, only PWV remained higher in those with AA, whereas in patients >60 yr, both PWV and SDPTG AI remained higher in those with AA. The PWV was independently influenced by age, systolic blood pressure, glucose, AA, and plasma creatinine, whereas the PTG AUI was influenced by age and systolic pressure and the SDPTG AI by age and AA. In a logistic regression model for the presence of AA, including age, plasma creatinine, smoking, and diastolic BP, PWV was a significant independent determinant of AA, whereas SDPTG-AI weakly entered into the model. This study provides evidence that the aortic PWV reflects better than the SDPTG the modifications of the arterial compliance related to age, blood pressure, and atherosclerosis. However, the SDPTG AI may be useful for evaluation of vascular aging in hypertensives.

Aged↗
PubMed2000

Long-term cardiovascular effects of high "osteoprotective" dose levels of 17 beta-estradiol in spontaneously hypertensive rats.

The effects of estrogen replacement therapy in menopausal women are more obvious on bones than on the cardiovascular system. The optimal estrogen dosage may differ in these different parts of the body. In hypertensive rats, low doses have been shown to reduce arterial collagen and stiffness, whereas higher dosages are required for osteoprotection. From 4 to 20 weeks of age, female spontaneously hypertensive rats (SHRs) were divided into four groups: without ovariectomy, under placebo or 17 beta-estradiol (10 micrograms/kg/day), and with ovariectomy under either placebo or 17 beta-estradiol (same dosage). Serial tail systolic blood pressure measurements were performed, and histomorphometry of the thoracic aorta was determined at the end of the study. Under estrogen, blood pressure was unchanged, whereas the aortic wall-to-lumen ratio was increased, particularly in the presence of ovariectomy. The elastin to collagen ratio was significantly decreased, due both to a decrease in elastin and an increase in collagen density, with no change in media thickness. The latter findings were not observed when ovariectomy was performed. Independent of changes in wall stress, high-dose estrogen increases the aortic extracellular matrix in female SHRs. This increase may be reversed in the presence of ovariectomy, suggesting that estrogen was not the only gonadal factor responsible for altered vascular structure and function.

Animals↗
PubMed2000

Stiffness of carotid artery wall material and blood pressure in humans: application to antihypertensive therapy and stroke prevention.

BACKGROUND AND PURPOSE: Because epidemiological studies show that increased pulse pressure and carotid wall-material stiffness are predictors of cardiovascular mortality independent of age, atherosclerosis, and conventional risk factors, the relationships between carotid wall stiffness and blood pressure are important to the optimization of cardiovascular prevention. SUMMARY OF REVIEW: In middle-aged hypertensive patients, mean and pulse pressures are increased, and systolic and diastolic pressures are increased to the same degree as mean pressure. Carotid hypertrophy is associated with normal wall stress, but no increased stiffness of wall material has been reported. With age, the normal wall stress is associated with a larger diameter and a stiffer material of carotid but not peripheral arteries. The stiffer wall involves calcifications, large amounts of collagen, and fragmentation and rupture of elastic tissue, which results in increased pulse-wave velocity and alterations of amplitude and timing of wave reflections and thus causes a disproportionate increase in systolic and pulse pressure. During this period, acutely administered nitrates in elderly subjects are able to reduce selectively systolic and pulse pressures without altering diastolic and mean blood pressure and composition of the carotid wall. CONCLUSIONS: New therapeutic approaches acting mainly on the wall of large arteries are needed to treat hypertension in elderly patients and prevent stroke and myocardial infarction. These drugs could either selectively lower pulse pressure through changes in wave reflections (as nitrates do) or decrease arterial wall stiffness through modification of the composition of material (such as compounds that act on collagen cross-linking).

Aging↗
PubMed2000

Latina mothers' attributions, emotions, and reactions to the problem behaviors of their children with developmental disabilities.

We examined the applicability of attribution theory to mothers' perceptions and reactions to their child's problem behavior. Participants were 149 Latina mothers of children with developmental disabilities who were interviewed regarding specific incidents in which their child exhibited a behavior problem. The findings indicate that most mothers viewed their child as not being responsible for the behavior problem. Furthermore, as predicted by attribution theory, mothers who ascribed relatively high responsibility to the child were significantly more likely to report negative emotions (anger and frustration) and aggressive/harsh behavioral reactions than mothers who ascribed low responsibility. Also. mothers were more likely to ascribe high responsibility to the child when the problem was characterized as a behavioral excess than as a behavioral deficit. The results provide support for the applicability of an attributional framework and may have important implications for helping parents in addressing the problem behaviors of their children with developmental disabilities.

Adolescent↗
PubMed1999

[Homocysteine and cardiovascular disease: what is the connection?].

HYPERHOMOCYSTEINEMIA: There are experimental data arguing for a role of homocysteine in several processes involved in atherosclerosis. Multiple retrospective and prospective studies performed in populations with high cardiovascular risk have shown that high homocysteine levels are associated with increased risk of coronary artery disease, stroke and peripheral vascular disease. In populations free of cardiovascular disease, prospective studies have demonstrated that homocysteine is a risk factor for cardiovascular disease while in other publications, no such prognostic value is found for high serum levels of homocysteine. PERSPECTIVE AND PREVENTION: There are highly promising perspectives for prevention due to the fact that serum homocysteine levels fall off systematically after simple dietary supplementation with vitamin B. Nevertheless, there is no formal proof to date from therapeutic trials suggesting that such a supplementation would reduce the risk of cardiovascular disease. FURTHER INFORMATION REQUIRED: In terms of epidemiology and clinical expression, further research into homocysteine as a cardiovascular risk factor should not be based on case-control studies which can be expected to provide information of limited usefulness, but rather on interventional trials to determine the primary or secondary preventive effect on cardiovascular disease. A large-scale pragmatic study using diet supplementation in a wide population might provide answers to still open questions.

Arteriosclerosis↗
PubMed1999

Impact of aortic stiffness on survival in end-stage renal disease.

BACKGROUND: Damage to large arteries is a major factor in the high cardiovascular morbidity and mortality of patients with end-stage renal disease (ESRD). Increased arterial stiffness and intima-media thickness, together with increased pulse pressure, are the principal arterial alterations. Whether increased aortic pulse-wave velocity (PWV), a classic marker of increased arterial stiffness, may predict all-cause and/or cardiovascular mortality has never been investigated. METHODS AND RESULTS: A cohort of 241 patients with ESRD undergoing hemodialysis was studied between April 1987 and April 1998. The mean duration of follow-up was 72+/-41 months (mean+/-SD). Mean age at entry was 51.5+/-16.3 years. Seventy-three deaths occurred, including 48 cardiovascular and 25 noncardiovascular fatal events. At entry, together with standard clinical and biochemical analyses, patients underwent echocardiography and aortic PWV measured by Doppler ultrasonography. On the basis of Cox analyses, 2 factors emerged as predictors of all-cause and cardiovascular mortality: age and aortic PWV. Hemoglobin and low diastolic pressure interfered to a smaller extent. After adjustment for all the confounding factors, an OR for PWV >12. 0 versus <9.4 m/s was 5.4 (95% CI, 2.4 to 11.9) for all-cause mortality and 5.9 (95% CI, 2.3 to 15.5) for cardiovascular mortality. For each PWV increase of 1 m/s in our study population, all-cause mortality-adjusted OR was 1.39 (95% CI, 1.19 to 1.62). CONCLUSIONS: These results provide the first direct evidence that in patients with ESRD, increased aortic stiffness determined by measurement of aortic PWV is a strong independent predictor of all-cause and mainly cardiovascular mortality.

Adult↗
PubMed1999

Influence of age and end-stage renal disease on the stiffness of carotid wall material in hypertension.

BACKGROUND: Incremental elastic modulus, which is the slope of the relationship between stress and strain of arterial vessels, is a marker of wall material stiffness. The radial artery incremental elastic modulus, which is not influenced by age, is normal or reduced in patients with essential hypertension but increased in patients with end-stage renal disease. Authors of studies on hypertension largely ignore the question of whether the incremental elastic modulus, measured in the common carotid artery as typical of a central artery site, differs according to age or to the presence of end-stage renal disease or both. SUBJECTS AND METHODS: The carotid incremental elastic modulus was measured in 208 hypertensive patients divided into four groups according to age (< or = or > 55 years) and the presence or absence of end-stage renal disease. The incremental elastic modulus was calculated from transcutaneous measurements of arterial internal diameter and wall thickness (echo-tracking device) and carotid pulse pressure (tonometry). Because the four groups of subjects had the same mean arterial pressure, the static incremental elastic modulus was calculated both in isobaric conditions and for the same wall stress. RESULTS: In nonuremic subjects, lumen diameter, wall thickness and the incremental elastic modulus were significantly (P < 0.001) increased in older subjects whereas compliance and distensibility were decreased. The mean (+/- SD) elastic modulus was 0.41 +/- 0.14 x 10(3) kPa in younger and 0.71 +/- 0.28 x 10(3) kPa in older subjects. In uremic subjects, the corresponding values were 0.48 +/- 0.30 and 0.90 +/- 0.49 x 10(3) kPa, and therefore higher than in nonuremic subjects, irrespective of age. Multiple regression analysis showed that age, mean arterial pressure and the presence of end-stage renal disease independently influenced carotid diameter, distensibility and the incremental elastic modulus. CONCLUSIONS: In hypertensive patients, the carotid incremental elastic modulus is increased independently in aging men and women and in the presence of uremia. This increase is not dependent on mechanical factors such as the level of mean blood pressure.

Adult↗
PubMed1999

Aortic pulse wave velocity as a marker of cardiovascular risk in hypertensive patients.

Large artery damage is a major contributory factor to cardiovascular morbidity and mortality of patients with hypertension. Pulse wave velocity (PWV), a classic evaluation of arterial distensibility, has never been ascertained as a cardiovascular risk marker. To determine the factors influencing aortic PWV and the potential predictor role of this measurement, we studied a cohort of 710 patients with essential hypertension. Atherosclerosis alterations (AA) were defined on the basis of clinical events. Calculation of cardiovascular risks, by use of Framingham equations, was performed in subjects without AA. PWV was higher in the presence of AA (14.9+/-4.0 versus 12.4+/-2.6 m/s, P<0.0001), even after adjustments on confounding factors and was the first determinant (P<0.0001) of the extent of atherosclerosis assessed as the sum of the atherosclerotic sites. In patients without AA, all cardiovascular risks increased constantly with PWV. Furthermore, at a given age, aortic PWV was the best predictor of cardiovascular mortality. The odds ratio of being in a high cardiovascular mortality risk group (>5% for 10 years) for patients in the upper quartile of PWV was 7.1 (95% confidence intervals 4.5 to 11.3). The presence of a PWV >13 m/s, taken alone, appeared as a strong predictor of cardiovascular mortality with high performance values. This study shows that aortic PWV is strongly associated with the presence and extent of atherosclerosis and constitutes a forceful marker and predictor of cardiovascular risk in hypertensive patients.

Age Factors↗
PubMed1999

Plasma homocysteine, aortic stiffness, and renal function in hypertensive patients.

Hyperhomocysteinemia has been associated with both vascular structure alterations and vascular clinical end points. To assess the relation between plasma homocysteine, structure and function of large arteries, and the presence of clinical vascular disease, we investigated a population of 236 hypertensive patients. We estimated arterial stiffness by measuring the carotid-femoral pulse wave velocity. Total plasma homocysteine was determined by fluorometric high-performance liquid chromatography. The presence of cardiovascular disease was defined on the basis of clinical events, including coronary heart disease, cerebrovascular disease, and peripheral vascular disease. In this population, pulse wave velocity was positively correlated with homocysteine, even after adjustments for age, mean blood pressure, extent of atherosclerosis, and creatinine clearance (P=0.016). Analysis of variance showed statistically significant differences between the mean values of homocysteine, creatinine clearance, and pulse wave velocity according to the extent of atherosclerosis, with an increase in these 3 parameters concomitant with an increase in the number of vascular sites involved with atherosclerosis. In conclusion, in hypertensive patients the levels of homocysteine are strongly and independently correlated to arterial stiffness measured by aortic pulse wave velocity. Plasma homocysteine, creatinine clearance, and aortic pulse wave velocity are higher in patients presenting with clinical vascular disease. These results suggest that the evaluation of aortic distensibility and homocysteine levels can help in cardiovascular risk assessment in hypertensive populations.

Adult↗
PubMed1999

Leaving or launching? Continuing family involvement with children and adolescents in placement.

Postplacement involvement and well-being of 53 families who had placed their child into a residential facility were studied. Parents were interviewed an average of 1, 2, and 3.5 years following placement. Visitation remained moderately high, with some type of visit reported at least monthly at Time 3 by 83% of families. Expressed attachment was high and stable, and most parents reported experiencing less guilt than at the time of placement. Parents were still thinking and talking about the child frequently. They were more likely, over time, to view the placement as permanent, and for about two thirds, the ideal placement was a residential facility. Virtually all parents reported family life to be better following placement, especially in recreation, social life, and relationships with their other children.

Adaptation, Psychological↗
PubMed1999

[Evaluation of the individual absolute cardiovascular risk. A mathematical equation and/or arterial measurement?].

The latest recommendations about the management of cardiovascular risk factors take into account not only the level of risk factor but also the global risk profile of the patient. The reference for the calculated estimation of absolute cardiovascular risk remains the Framingham equation. Nevertheless, this estimation has a number of operational and conceptual limitations such as geographical and historical validity and its application to individual cases. Different results in the medical literature suggest that parameters of arterial structure or function measured simply, such as arterial rigidity, could be closely related to the level of individual cardiovascular risk by the integration of the deleterious effects of different vascular risk factors over decades of exposition. They could then be better predict cardiovascular effects than the result of a mathematical equation which only integrates some of the risk factors at a given point in time. These simple, rapid and non-invasive measurements could help identify subjects at high cardiovascular risk and also help the clinician in the orientation of preventive measures in subjects with cardiovascular risk factors.

Adult↗
PubMed1999

[A new cause of resistant arterial hypertension: coprescription with anticonvulsant treatments].

UNLABELLED: This article provides two case reports about pharmacokinetic interactions with hypertensive drug therapy and anticonvulsive treatment. First, a 49-year-old patient presenting severe hypertension had a non-traumatic cerebral hemorrhage with convulsions. Extensive etiologic investigations did not find any cause of secondary hypertension. Under an association of four antihypertensive drugs regimen, associated with carbamazepine blood pressure was not controlled. Finally, blood pressure was well controlled after replacement of carbamazepine with vigabatrin. The second case reports a 64-year-old treatment-resistant essential hypertensive patient, carbamazepine was associated with antihypertensive treatment because of aggressivity attributed to Alzheimer's disease. After withdrawal of carbamazepine treatment, blood pressure reached normal values with the same antihypertensive regimen. Those case reports suggest drug-drug interactions between antihypertensive and anticonvulsive drug therapies. Following explanation can be hypothesis: several antihypertensive drugs are liver-metabolised by microsomal cytochrome P450 3A4 isoform that could explain a significantly decreased half-life in association with enzymatic inducers, such as rifampicine or antiepileptic drugs (phenobarbital, phenytoin or carbamazepine). CONCLUSION: When blood pressure is not controlled without cause of secondary hypertension, physicians must be careful with drug-drug interactions.

Anticonvulsants↗