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Biomedical subjects

P Larochelle

Publications and source records attributed to P Larochelle.

At least 19 recordsLinked to original sources
PubMed2001

Effects of individual risk factors on the incidence of cardiovascular events in the treated hypertensive patients of the Hypertension Optimal Treatment Study. HOT Study Group.

BACKGROUND: The Hypertension Optimal Treatment (HOT) Study has provided information about cardiovascular events in 18790 hypertensives, subjected to pronounced blood pressure (BP) lowering for a mean of 3.8 years. The HOT study data have subsequently been analysed after stratification of the patients according to global cardiovascular risk, and it has been found that, despite intensive blood pressure lowering in all risk strata, morbid event rates increased with increasing risk stratum. OBJECTIVES: Previously analysed global risk strata were based on combinations of risk factors. The analyses presented here were intended to provide information on the relative role that the presence of each individual factor may have in increasing cardiovascular risk, despite good BP control. METHODS: Risk ratios (RR) for patients with and those without a risk factor were calculated with 95% confidence intervals (CI) using a Cox proportional hazard model, and adjusted for all variables except the one under examination. RESULTS: For all risk factors considered and for all types of event, RR were always greater than 1, indicating a greater risk in the presence, compared with that in the absence of each factor. The male gender was a statistically significant risk for cardiovascular (CV) events, CV and total mortality and particularly for myocardial infarction (MI); age > or = 65 years for CV events, stroke, CV and particularly total mortality; smoking for all events analysed, but particularly for total mortality (twice higher in smokers than in non-smokers); high serum cholesterol (> 6.8 mmol/l) for CV events, MI and CV mortality; high serum creatinine (> 155 micromol/l) for CV events, stroke, CV and total mortality; diabetes for CV events, stroke, total mortality and particularly CV mortality; and ischaemic heart disease for all events analysed. Adjusted RR were often close to or greater than 2. CONCLUSIONS: Each of the risk factors considered was found to be an important cause of residual risk, despite good BP control. These findings emphasize the importance of addressing other correctable risk factors, e.g. smoking, hypercholesterolaemia and diabetes, as well as rigorous control of blood pressure, and of initiating antihypertensive therapy before cardiovascular and renal damage becomes manifest.

Aged↗
PubMed2000

Role of tumor necrosis factor-alpha gene locus in obesity and obesity-associated hypertension in French Canadians.

Obesity represents a serious risk factor for the development of cardiovascular diseases, including hypertension. Segregation studies suggest that obesity and obesity-associated hypertension may share some genetic determinants. The results of the present candidate gene investigation suggest that in hypertensive pedigrees of French-Canadian origin, one such determinant is the tumor necrosis factor (TNF)-alpha gene locus. Gender-pooled quantitative sib-pair analysis demonstrated a significant effect of the gene locus on 3 global and 7 regional measures of obesity (P=0.05 to 0.0004). Gender-separate quantitative sib-pair analyses showed that the impact of the locus on obesity is most significant in the abdominal region in men and in the thigh region in women. Furthermore, the haplotype relative-risk test demonstrated a significant association between the TNF-alpha gene locus and both obesity (P=0.006) and obesity-associated hypertension (P=0.02). These effects were most significant in individuals with nonmorbid obesity. In conclusion, the results of linkage and association analyses suggest that in hypertensive pedigrees of French-Canadian origin, the TNF-alpha gene locus contributes to the determination of obesity and obesity-associated hypertension. In addition, the data indicate that gender modifies the effect of the locus on the regional distribution of body fat.

Body Mass Index↗
PubMed2000

[Calcium channel blocking agents and albuminuria in diabetic and hypertensive patients. A pilot study].

UNLABELLED: Diltiazem tends to decrease proteinuria in hypertensive diabetic subjects in comparison to amlodipine that does not modify it. Since estimated glomerular pressure is identical in amlodipine treated and diltiazem treated subjects, differences in albuminuria may be explained by different renal tubular reabsorption rates. OBJECTIVES: To compare plasma clearances (PC) of technetium labeled albumin (albumin-Tc99m) obtained by serial plasma measurements with PC obtained by urinary excretion measurements. Indirectly evaluate tubular reabsorption of albumin-Tc99m. Test the hypothesis that amlodipine decreases renal tubular reabsorption of albumin in diabetic hypertensive subjects. METHODS: Fourteen diabetic and hypertensive subjects (DH) (average plasma creatinine: 94 mmol/L) and 6 normal subjects (average plasma creatinine: 82 mmol/L) had previously been assessed for albumin-Tc99m PC. Eleven of these 14 DH subjects were then randomized to diltiazem 300 mg/daily (6 subjects) or amlodipine 10 mg/daily (5 subjects). Their glomerular filtration, glomerular pressure and albumin-Tc99m PC were then assessed on the 3rd, 6th, and 12th month of the study. RESULTS: Albumin-Tc99m PC obtained from serial blood draws: A decrease in PC between months 0 and 3 from 14 to 10.6 cc/min was observed in subjects treated with amlodipine but subjects on diltiazem showed PC stability (from 11.9 to 12 cm3/min). PC obtained from urinary excretion: Amlodipine and diltiazem treated subjects showed PC stability. Plasma volume in amlodipine treated subjects decreased from 156 to 127% and diltiazem treated subjects from 128 to 117%. CONCLUSION: A decrease in PC obtained with plasma measurements and stability of PC based on urinary excretion measurements tends to identify a decrease in plasma volume. A decrease in albumin-Tc99m tubular reabsorption was not observed. The estimate of albumin PC with Tc 99m labelled albumin measurements still needs to be validated.

Absorption↗
PubMed1999

Lifestyle modifications to prevent and control hypertension. 5. Recommendations on dietary salt. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada.

OBJECTIVE: To provide updated, evidence-based recommendations concerning the effects of dietary salt intake on the prevention and control of hypertension in adults (except pregnant women). The guidelines are intended for use in clinical practice and public education campaigns. OPTIONS: Restriction of dietary salt intake may be an alternative to antihypertensive medications or may supplement such medications. Other options include other nonpharmacologic treatments for hypertension and no treatment. OUTCOMES: The health outcomes considered were changes in blood pressure and in morbidity and mortality rates. Because of insufficient evidence, no economic outcomes were considered. EVIDENCE: A MEDLINE search was conducted for the period 1966-1996 using the terms hypertension, blood pressure, vascular resistance, sodium chloride, sodium, diet, sodium or sodium chloride dietary, sodium restricted/reducing diet, clinical trials, controlled clinical trial, randomized controlled trial and random allocation. Both trials and review articles were obtained, and other relevant evidence was obtained from the reference lists of the articles identified, from the personal files of the authors and through contacts with experts. The articles were reviewed, classified according to study design and graded according to level of evidence. In addition, a systematic review of all published randomized controlled trials relating to dietary salt intake and hypertension was conducted. VALUES: A high value was placed on the avoidance of cardiovascular morbidity and premature death caused by untreated hypertension. BENEFITS, HARMS AND COSTS: For normotensive people, a marked change in sodium intake is required to achieve a modest reduction in blood pressure (there is a decrease of 1 mm Hg in systolic blood pressure for every 100 mmol decrease in daily sodium intake). For hypertensive patients, the effects of dietary salt restriction are most pronounced if age is greater than 44 years. A decrease of 6.3 mm Hg in systolic blood pressure and 2.2 mm Hg in diastolic blood pressure per 100 mmol decrease in daily sodium intake was observed in people of this age group. For hypertensive patients 44 years of age and younger, the decreases were 2.4 mm Hg for systolic blood pressure and negligible for diastolic blood pressure. A diet in which salt is moderately restricted appears not to be associated with health risks. RECOMMENDATIONS: (1) Restriction of salt intake for the normotensive population is not recommended at present, because of insufficient evidence demonstrating that this would lead to a reduced incidence of hypertension. (2) To avoid excessive intake of salt, people should be counselled to choose foods low in salt (e.g., fresh fruits and vegetables), to avoid foods high in salt (e.g., pre-prepared foods), to refrain from adding salt at the table and minimize the amount of salt used in cooking, and to increase awareness of the salt content of food choices in restaurants. (3) For hypertensive patients, particularly those over the age of 44 years, it is recommended that the intake of dietary sodium be moderately restricted, to a target range of 90-130 mmol per day (which corresponds to 3-7 g of salt per day). (4) The salt consumption of hypertensive patients should be determined by interview. VALIDATION: These recommendations were reviewed by all of the sponsoring organizations and by participants in a satellite symposium of the fourth International Conference on Preventive Cardiology. They have not been clinically tested. SPONSORS: The Canadian Hypertension Society, the Canadian Coalition for High Blood Pressure Prevention and Control, the Laboratory Centre for Disease Control at Health Canada, and the Heart and Stroke Foundation of Canada.

Adult↗
PubMed1999

Sibling resemblance of erythrocyte ion transporters in French-Canadian sibling-pairs affected with essential hypertension.

OBJECTIVES: Erythrocyte Na+/Li+ countertransport and Na+,K+ cotransport are increased in some Caucasians with essential hypertension. This study examines the relative contributions of genetic and shared environmental factors to the activity of these ion carriers in French-Canadian sibling-pairs affected with essential hypertension. DESIGN: The activity of Na+/Li+ countertransport and Na+,K+ cotransport (rate of Na+ o-dependent Li+ efflux and bumetanide-sensitive 86Rb influx, respectively) was measured in 122 French-Canadian siblings with essential hypertension, including 36 brother/brother and 48 sister/sister pairs. Sibling/sibling correlations were estimated using the FCOR program of the S.A.G.E. package. RESULTS: Na+/Li+ countertransport and Na+,K+ cotransport were respectively higher by 27% (P = 0.002) and 42% (P = 0.0009) in erythrocytes from men compared with women. Intra-individual correlation analysis did not reveal a significant effect of age on the activity of these ion transporters in both males and females, and an influence of plasma lipids (triglycerides, cholesterol, low-density lipoprotein, high-density lipoprotein) in females. In males, Na+,K+ cotransport was correlated with the level of serum triglycerides only (P = 0.01). Familial correlation analysis showed that sibling resemblance of Na+/Li+ countertransport and Na+,K+ cotransport was higher in men (r = 0.26 and 0.39) than in women (r = 0.01 and 0.03, respectively). CONCLUSION: The present data indicate that different factors contribute to the regulation of monovalent ion carriers in erythrocytes from Caucasian men and women with essential hypertension. The activity of erythrocyte Na+/Li+ countertransport and Na+,K+ cotransport appears to be more strongly determined by inheritable factors in men than in women.

Adult↗
PubMed1999

Effects of antihypertensive therapies on the sympathetic nervous system.

The sympathetic nervous system is a major modulator of cardiovascular function. Over the past three decades, numerous studies, using various methodologies, have reported the existence of a variety of pre- and postsynaptic sympathetic dysfunctions in essential hypertension. Most of these abnormalities facilitate sympathetic neurotransmission, resulting in a chronic increase in the sympathetic tone and reactivity in a significant proportion of hypertensive patients. Chronic sympathetic activation is also associated with major alterations in the balance among postsynaptic adrenergic receptors in cardiovascular tissues. Indeed, an attenuation of beta-adrenergic function and a potentiation of alpha1-adrenergic function has been demonstrated in cardiovascular tissues in hypertensive patients, suggesting the development of a sympathetic postsynaptic alpha1 dominance during the development and evolution of hypertension. Chronic activation of the sympathetic system is deleterious and could contribute to the development of most cardiovascular complications associated with hypertension. One of the major aims of antihypertensive therapy should thus be to attenuate pre- or postsynaptic sympathetic tone. Most antihypertensive drugs have been found to improve either pre- or postsynaptic sympathetic function in hypertensive patients. At the presynaptic level, diuretics were found to increase the liberation of noradrenalin, presumably through baroreflex sympathetic activation. In contrast, beta-blockers were shown to attenuate noradrenalin release from sympathetic nerves by blocking presynaptic facilitatory beta-receptors, thus reducing the sympathetic tone on postsynaptic receptors. Similarly, angiotensin-converting enzyme inhibitors or angiotensin II type 1 (AT1) receptor antagonists have been found to reduce sympathetic reactivity by acting on the central nervous system, but also by blocking AT1-mediated facilitatory mechanisms located on sympathetic fibres and in the adrenal medulla. Short acting dihydropyridine calcium channel blockers (CCBs) were found to enhance noradrenalin release from sympathetic nerves, but longer acting CCBs seems to have variable effects. Indeed, while the chronic slow release formulation of nifedipine gastrointestinal therapeutic system (GITS) did not raise circulating noradrenalin levels, treatment with amlodipine increased circulating noradrenalin levels, suggesting that nifedipine GITS is neutral on the sympathetic tone but that amlodipine chronically activates the sympathetic system. At the postsynaptic level, however, dihydropyridine CCBs were shown to attenuate the sympathetic tone on alpha1-adrenoceptors. In conclusion, it appears that most antihypertensive drugs interfere with pre- or postsynaptic sympathetic mechanisms and that these mechanisms could contribute to their hypotensive effects.

Adrenergic Antagonists↗
PubMed1999

1999 Canadian recommendations for the management of hypertension. Task Force for the Development of the 1999 Canadian Recommendations for the Management of Hypertension.

OBJECTIVE: To provide updated, evidence-based recommendations for health care professionals on the management of hypertension in adults. OPTIONS: For patients with hypertension, there are both lifestyle options and pharmacological therapy options that may control blood pressure. For those patients who are using pharmacological therapy, a range of antihypertensive drugs is available. The choice of a specific antihypertensive drug is dependent upon the severity of the hypertension and the presence of other cardiovascular risk factors and concurrent diseases. OUTCOMES: The health outcomes considered were changes in blood pressure and in morbidity and mortality rates. Because of insufficient evidence, no economic outcomes were considered. EVIDENCE: MEDLINE searches were conducted from the period of the last revision of the Canadian Recommendations for the Management of Hypertension (January 1993 to May 1998). Reference lists were scanned, experts were polled and the personal files of the authors were used to identify other studies. All relevant articles were reviewed, classified according to study design and graded according to levels of evidence. VALUES: A high value was placed on the avoidance of cardiovascular morbidity and premature death caused by untreated hypertension. BENEFITS: Harms and costs: The diagnosis and treatment of hypertension with pharmacological therapy will reduce the blood pressure of patients with sustained hypertension. In certain settings, and for specific drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and mortality. RECOMMENDATIONS: This document contains detailed recommendations pertaining to all aspects of the diagnosis and pharmacological therapy of hypertensive patients. With respect to diagnosis, the recommendations endorse the greater use of non-office-based measures of blood pressure control (i.e., using home blood pressure and automatic ambulatory blood pressure monitoring equipment) and greater emphasis on the identification of other cardiovascular risk factors, both in the assessment of prognosis in hypertension and in the choice of therapy. On the treatment side, lower targets for blood pressure control are advocated for some subgroups of hypertensive patients, in particular, those with diabetes and renal disease. Implicit in the recommendations for therapy is the principle that for the vast majority of hypertensive patients treated pharmacologically, practitioners should not follow a stepped-care approach. Instead, therapy should be individualized, based on consideration of concurrent diseases, both cardiovascular and noncardiovascular. VALIDATION: All recommendations were graded according to the strength of the evidence and the consensus of all relevant stakeholders. SPONSORS: The Canadian Hypertension Society and the Canadian Coalition for High Blood Pressure Prevention and Control.

Adult↗
PubMed1999

Clinical problem solving based on the 1999 Canadian recommendations for the management of hypertension.

The 1999 Canadian Recommendations for the Management of Hypertension are notable for the trends that they represent with regard to the evolution of the management of hypertension. Diagnostically, the Recommendations endorse the greater use of non-office-based measures of blood pressure control and greater emphasis on the assessment of other atherosclerotic risk factors, both when considering prognosis in hypertension and in the choice of therapy. On the treatment side of the equation, lower targets for blood pressure control have been advocated in subgroups of hypertensive patients, particularly in those with diabetes and renal disease. In conjunction with the recently published recommendations on lifestyle management, there is a greater emphasis on lifestyle modification, both as initial and adjunctive therapy in hypertension. Implicit in the recommendations for therapy is the principle that for the vast majority of hypertensive patients treated pharmacologically, practitioners should not follow a stepped-care approach. Instead, therapy should be individualized, primarily based on consideration of concurrent diseases, both cardiovascular and noncardiovascular (Tables 1 and 2). Through the consensus process, there was a general appreciation of how far we have come in the development of evidence-based recommendations for hypertension management. However, there was also an increasing appreciation of how far we have to go in effectively translating these recommendations into better blood pressure control.

Adult↗
PubMed1998

A randomized, double-blind, placebo-controlled, parallel-group, multicenter trial of four doses of tasosartan in patients with essential hypertension. Tasosartan Investigator's Group.

Tasosartan, a new, long-acting, nonpeptide angiotensin II receptor antagonist was evaluated in a randomized, double-blind, placebo-controlled, multicenter trial at 21 sites in the United States and Canada. After a 2-week, placebo washout qualification period, 278 patients (187 men/91 women) with a mean age of 53.4+/-9.5 years (range, 30 to 70 years) and a baseline sitting diastolic blood pressure (DBP) of 95 to 114 mm Hg were randomly assigned to receive placebo (n = 56), or 10 mg (n = 57), 30 mg (n = 55), 100 mg (n = 55), or 300 mg (n = 55) tasosartan for 4 weeks. The treatment period was followed by a 2-week washout period. Ambulatory blood pressure (BP) monitoring was performed at the end of the placebo washout period and after at least 4 weeks of double-blind treatment. Clinically significant placebo-adjusted differences in baseline sitting systolic blood pressure (SBP)/DBP were observed in the 10 mg (5/3 mm Hg), 30 mg (5/4 mm Hg), 100 mg (10/7 mm Hg) and 300 mg (10/7 mm Hg) dose groups (P < .05). A dose-response relationship (P < .001) was observed within 1 to 2 weeks of treatment initiation and was maintained throughout the double-blind period. Discontinuation of tasosartan therapy was not associated with rebound hypertension. Moreover, significant (P < .05) placebo-adjusted differences in ambulatory SBP/DBP and a significant dose-response relationship (P < .001) were observed with all tasosartan dosages during the 24-h, daytime, and nighttime periods. Placebo-adjusted trough-to-peak ratios ranged from 87% to 100% for ambulatory SBP and 64% to 81% for DBP. In general, no significant differences were observed between the tasosartan treatment groups and the placebo group in the incidence of adverse events. Headache incidence was significantly lower in the 300 mg dose group than the placebo group. In conclusion, tasosartan at dosages of 10, 30, 100, or 300 mg given once daily produced a significant and dose-related reduction in both clinic and ambulatory BP that was maintained over the 24-h period. Tasosartan was generally well tolerated.

Adult↗
PubMed1998

Different effects of nifedipine and amlodipine on circulating catecholamine levels in essential hypertensive patients.

OBJECTIVE: To compare the acute and chronic effects of nifedipine retard (NPA), nifedipine gastrointestinal therapeutic system (NGITS) and amlodipine at trough and peak plasma concentrations of drug on blood pressure and heart rate, and on plasma norepinephrine and epinephrine levels in patients with mild-to-moderate hypertension (diastolic blood pressure 95-115 mmHg). DESIGN AND METHODS: After 3-4 weeks' placebo treatment, patients of both sexes were randomly allocated to be administered 10 or 20 mg NPA twice a day, 30 or 60 mg NGITS once a day, and 5 or 10 mg amlodipine once a day for 6 weeks. Initially, for the first 2 weeks, the lowest dose of each drug was used, but higher doses were administered after 2 weeks if sitting diastolic blood pressure was > 90 mmHg. Patients were evaluated after administration of the first dose and after 6 weeks' therapy in a hospital setting. Blood samples were taken for high-performance liquid chromatography measurement of catecholamine and drug levels at various intervals for a period covering trough to peak drug level ranges. RESULTS: Administration of all three drugs reduced clinic blood pressure to the same level after 6 weeks' therapy, but heart rate was increased slightly only with amlodipine (P < 0.05). Administration of NPA reduced blood pressure more abruptly whereas administrations of NGITS and amlodipine induced smoother falls after acute and chronic treatments: a significant increase in heart rate was observed with amlodipine after chronic treatment. Both acute and chronic treatments with NPA (n = 19) increased norepinephrine levels (P < 0.01) transiently (2-4 h). In contrast, administration of NGITS (n = 22) did not increase norepinephrine levels and even induced a slight but significant decrease in norepinephrine levels 5-6 h after chronic treatments. Although administration of amlodipine (n = 22) did not increase norepinephrine levels transiently either after acute or after chronic administration, it did induce a sustained rise in basal norepinephrine levels by more than 50% after chronic therapy (P < 0.01). Plasma epinephrine levels were not increased by any of the treatments and even a slight decrease was observed 4 h after administration of a dose following chronic treatments with NGITS and amlodipine (P < 0.05). CONCLUSIONS: The transient increase in norepinephrine levels observed with NPA and the sustained increases in norepinephrine levels observed after chronic treatment with amlodipine suggest that sympathetic activation occurs with those two drugs. The lack of increase in norepinephrine levels after administration of NGITS suggests that this formulation does not activate the sympathetic system. The lowering of epinephrine levels after administrations of NGITS and amlodipine suggests that inhibition of release of epinephrine by the adrenal medulla occurs with longer-acting dihydropyridine formulations.

Adult↗
PubMed1998

Different effects of nifedipine and amlodipine on circulating catecholamine levels in essential hypertensive patients.

OBJECTIVE: To compare the acute and chronic effects of nifedipine retard (NPA), nifedipine gastrointestinal therapeutic system (NGITS) and amlodipine at trough and peak plasma concentrations of drug on blood pressure and heart rate, and on plasma norepinephrine and epinephrine levels in patients with mild-to-moderate hypertension (diastolic blood pressure 95-115 mmHg). DESIGN AND METHODS: After 3-4 weeks' placebo treatment, patients of both sexes were randomly allocated to be administered 10 or 20 mg NPA twice a day, 30 or 60 mg NGITS once a day, and 5 or 10 mg amlodipine once a day for 6 weeks. Initially, for the first 2 weeks, the lowest dose of each drug was used, but higher doses were administered after 2 weeks if sitting diastolic blood pressure was > 90 mmHg. Patients were evaluated after administration of the first dose and after 6 weeks' therapy in a hospital setting. Blood samples were taken for high-performance liquid chromatography measurement of catecholamine and drug levels at various intervals for a period covering trough to peak drug level ranges. RESULTS: Administration of all three drugs reduced clinic blood pressure to the same level after 6 weeks' therapy, but heart rate was increased slightly only with amlodipine (P < 0.05). Administration of NPA reduced blood pressure more abruptly whereas administrations of NGITS and amlodipine induced smoother falls after acute and chronic treatments: a significant increase in heart rate was observed with amlodipine after chronic treatment. Both acute and chronic treatments with NPA (n = 19) increased norepinephrine levels (P < 0.01) transiently (2-4 h). In contrast, administration of NGITS (n = 22) did not increase norepinephrine levels and even induced a slight but significant decrease in norepinephrine levels 5-6 h after chronic treatments. Although administration of amlodipine (n = 22) did not increase norepinephrine levels transiently either after acute or after chronic administration, it did induce a sustained rise in basal norepinephrine levels by more than 50% after chronic therapy (P < 0.01). Plasma epinephrine levels were not increased by any of the treatments and even a slight decrease was observed 4 h after administration of a dose following chronic treatments with NGITS and amlodipine (P < 0.05). CONCLUSIONS: The transient increase in norepinephrine levels observed with NPA and the sustained increases in norepinephrine levels observed after chronic treatment with amlodipine suggest that sympathetic activation occurs with those two drugs. The lack of increase in norepinephrine levels after administration of NGITS suggests that this formulation does not activate the sympathetic system. The lowering of epinephrine levels after administrations of NGITS and amlodipine suggests that inhibition of release of epinephrine by the adrenal medulla occurs with longer-acting dihydropyridine formulations.

Adult↗
PubMed1997

Effects and tolerability of irbesartan versus enalapril in patients with severe hypertension. Irbesartan Multicenter Investigators.

In this double-blind, randomized study, an antihypertensive regimen based on irbesartan, an angiotensin II receptor antagonist, reduced systolic and diastolic blood pressure by 40/30 mm Hg at week 12 in patients with severe hypertension; this reduction was at least equivalent to that of a regimen using enalapril up to 40 mg. The irbesartan-based regimen had a better tolerability profile with fewer adverse events (55% vs 64%) and significantly less cough (2.5% vs 13.1%, p = 0.007).

Angiotensin II↗
PubMed1997

Patterns of compliance with once versus twice daily antihypertensive drug therapy in primary care: a randomized clinical trial using electronic monitoring.

OBJECTIVE: To evaluate patterns of compliance with once versus twice daily administration of antihypertensive therapy (primary-outcome measure) and relevance of partial compliance for blood pressure control (secondary outcome measure). DESIGN: Multicentre, nonblinded, parallel group randomized design. SETTING: Nonacademic primary care practices across Canada. STUDY POPULATION: Patients with mild essential hypertension (diastolic blood pressure 95 to 110 mmHg) of either sex (40% women), age 18 to 80 years (average 55 years). One hundred and ninety-eight patients were randomized to active treatment; 14 patients discontinued the study because of side effects. INTERVENTIONS: After a four-week placebo run-in period, patients were randomized to amlodipine 5 mg once-a-day or diltiazem slow release formulation (SR) 90 mg twice daily. Doses were increased to 10 mg and 180 mg to achieve sitting diastolic blood pressure of 90 mmHg or less. OUTCOME MEASURE: During 20 weeks on active treatment, compliance was assessed by pill counts and medication event monitoring system (MEMS), assessing percentage of prescribed doses taken, percentage days correct doses taken, percentage prescribed doses taken on time and blood pressure control as determined by office blood pressure measurement. RESULTS: The percentage prescribed doses taken (by either pill count of MEMS) showed a high degree of compliance, similar for the two treatments. However, other parameters of compliance were significantly better with once versus twice daily therapy. Partial compliance (less than 80% by pill count) led to less blood pressure control with the short acting diltiazem, but did not affect blood pressure control for the long acting amlodipine. Side effects profiles did not differ between the two treatments. CONCLUSIONS: Within the constraints of a clinical trial, hypertensive patients in primary care show a high degree of overall compliance with once or twice daily pill-taking, but patterns of pill-taking are more erratic with twice versus once daily medication, particularly in men. The results suggest that the negative consequences of partial compliance for blood pressure control can be offset by choosing agents with a duration of action well beyond the dosing interval.

Adolescent↗
PubMed1996

Effect of quinapril on the albumin excretion rate in patients with mild to moderate essential hypertension. Multicenter Study Group.

In patients with essential hypertension, correlations have been reported between the albumin excretion rate (AER) and ambulatory and casual blood pressure. Microalbuminuria has been indicated as a possible predictor of cardiovascular morbidity and mortality. The objective of this trial was to evaluate the effect of quinapril, an angiotensin converting enzyme inhibitor with high tissue affinity for the enzyme, on the AER in patients with mild to moderate essential hypertension and no evidence of diabetes mellitus. In this 12 week, 24 center study, quinapril was administered to 213 patients and titrated to 10, 20, or 40 mg/day alone or 20 mg/day plus 12.5 mg/day hydrochlorothiazide. Overall, blood pressure was reduced from 155.2 +/- 18.1/101.8 +/- 6.7 mm HG (mean +/- SD) to 144.4 +/- 17.8/92.3 +/- 8.9 mm HG (P = .0001) and AER decreased from 20.6 +/- 24.3 mg/24 h to 14.5 +/- 15.4 mg/24 h (P = .0001). The BP reductions were significant in all age groups. AER at endpoint was reduced 37.5% in elderly, 29.8% in middle-aged, and 11.8% in young patients from 32.5 +/- 45.0 mg/24 h, 19.1 +/- 20.9 mg/24 h, and 16.1 +/- 16.9 mg/24 h, respectively. The AER decreased in 60% of patients who had normal AER (0 to 30 mg/24 h), in 79% of those who had microalbuminuria (30 to 300 mg/24 h), and in 90% of those who had proteinuria (> 300 mg/24 h) at baseline. Baseline log-AER correlated with SBP (P = .0126, R = 0.19) and creatinine clearance (P = .026, R = 0.17), while endpoint log-AER correlated with SBP (P = .0015, R = 0.25) and DBP (P = .03, R = 0.17). In summary, we showed, in a large group of patients with mild to moderate essential hypertension and no evidence of diabetes mellitus, that quinapril not only lowers BP significantly but also reduces microalbuminuria.

Albuminuria↗
PubMed1996

Prostaglandins and renal function in hypertensive patients with unilateral renal artery stenosis and patients with essential hypertension.

OBJECTIVE: This study was designed to compare the effects of prostaglandin synthesis inhibition on calculated preglomerular and postglomerular resistance in hypertensive patients with unilateral renal artery stenosis (RAS) and in patients with essential hypertension. DESIGN AND METHODS: Sixteen patients with suspected renovascular hypertension underwent renal angiography: eight had unilateral renal artery stenosis > or = 70% and eight had normal angiograms or stenosis < or = 40%. Radionuclide renography and 6 h urinary collection were performed twice for each subject, at baseline and after indomethacin administration. Levels of urinary vasodilatory prostaglandins were measured by specific radioimmunoassays. Visual image analysis was performed to determine the parenchymal transit time (PTT). The glomerular filtration rate (GFR) was calculated from the plasma clearance of [99mTc]-diethylenetriamine pentaacetic acid (DTPA). The preglomerular and postglomerular resistances were estimated according to Gomez's equations. RESULTS: The prostaglandin excretion decreased significantly after indomethacin administration both in RAS and in essential hypertension patients. The PTT increased from 230 +/- 10 to 340 +/- 40s in the stenotic kidney compared with the contralateral kidney and the kidneys of essential hypertension patients. The GFR was decreased both in stenotic and in contralateral kidneys (48 +/- 4 to 37 +/- 5 and 60 +/- 4 to 52 +/- 5 ml/min, respectively) but did not decline in the kidneys of essential hypertension patients. The preglomerular resistance increased both in stenotic and in contralateral kidneys, whereas it did not rise significantly in the kidneys of essential hypertension patients. The postglomerular resistance in stenotic and contralateral kidneys of RAS patients was not altered. CONCLUSIONS: Prostaglandins limit GFR decreases in RAS by preventing preglomerular constriction without interfering with postglomerular constriction. Thus, the action of vasoactive prostaglandins on preglomerular resistance might maintain renal function in the short term by limiting the fall in GFR in the stenotic kidney and by increasing the GFR in the contralateral kidney.

Blood Pressure↗
PubMed1995

Progressive improvement in the structure of resistance arteries of hypertensive patients after 2 years of treatment with an angiotensin I-converting enzyme inhibitor. Comparison with effects of a beta-blocker.

To investigate the effects of antihypertensive drugs on resistance artery structure, 17 essential hypertensive patients were randomly assigned to be treated with an angiotensin I-converting enzyme inhibitor, cilazapril, or a beta-blocker, atenolol, for 2 years. Blood pressure was well controlled throughout the 2 years. Before starting treatment, at the end of the first year and at the end of the second year, patients were subjected to gluteal subcutaneous fat biopsies, from which resistance-size arteries were dissected to be studied. The media width to lumen diameter ratio of arteries from patients in the cilazapril group was 7.5 +/- 0.3% before starting treatment, and decreased significantly (P < .05) to 6.3 +/- 0.2% at the end of the first year, and to 5.8 +/- 0.2% at the end of the second year, at which time it was not different from that of arteries from normotensive subjects (5.2 +/- 0.2%). In patients treated with atenolol, resistance arteries exhibited a media-to-lumen ratio of 8.0 +/- 0.6% before treatment, 8.1 +/- 0.5% after 1 year of treatment, and 7.9 +/- 0.3% at the end of the second year of treatment, all significantly higher (P < .01) than that of arteries from normotensive subjects. Thus, treatment for 2 years with the angiotensin I-converting enzyme inhibitor cilazapril resulted in progressive normalization of the structure (media-to-lumen ratio) of gluteal subcutaneous fat resistance arteries of essential hypertensive patients, whereas there was no change in patients treated with the beta-blocker atenolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗