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Biomedical subjects

L R Krakoff

Publications and source records attributed to L R Krakoff.

At least 37 records · Page 2Linked to original sources
PubMed1995

Defining the patient group for cost-effective withdrawal of antihypertensive therapy.

Many people receiving drug treatment for hypertension have had good control of their blood pressure for several years. It is feasible, and might be desirable, to discontinue drug treatment in selected groups of these patients if their long term outcome was not adversely affected. A few small series and 2 larger trials indicate that withdrawal of antihypertensive medication can be followed by 1 to 4 years of normal blood pressure, especially for those with mild hypertension (pretreatment diastolic blood pressure < 100mm Hg) and who have no evidence of target organ damage. In the 2 randomised trials of withdrawing medication emerging from the High Blood Pressure Detection and Follow-up Program, the addition of nutritional interventions (bodyweight reduction and/or dietary salt restriction) was shown to enhance the likelihood that antihypertensive drugs could be deferred for long intervals. Sustained bodyweight reduction for overweight patients with mild hypertension was the most successful approach. Short term nonpharmacological programmes have been evaluated for their economic effects on this process through cost-effectiveness and cost-benefit analyses. The available studies imply that reduced costs and decreased adverse effects associated with withdrawal of antihypertensive medication are offset by cost of the nonpharmacological interventions needed to maximise continued blood pressure control. Other influences, such as willingness to pay for nonpharmacological management or change in sense of well-being when on or off medication, need consideration for comprehensive cost-effectiveness analyses.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive Agents↗
PubMed1994

Persistent white coat hypertension.

Serial observations of clinic and ambulatory blood pressure monitoring are presented for a 60-year-old woman whose arterial blood pressure was unaffected by removal of a functioning parathyroid adenoma. A pattern of "white coat hypertension" first detected 8 years ago remains unchanged to the present.

Adenoma↗
PubMed1993

Ambulatory blood pressure monitoring can improve cost-effective management of hypertension.

Detection and treatment of arterial hypertension is effective, as shown by clinical trials and downward trends in cardiovascular disease. This process causes expenditures that progressively have increased because of inclusion of more patients with minimally elevated pressure who incur a higher cost of treatment. Average daily pressure is a more accurate predictor of outcome and morbidity than initial screening or occasional clinic monitoring of pressure. Noninvasive ambulatory blood pressure monitoring (ABPM), as a secondary screening, reveals that 20% to 60% of those initially labeled as hypertensive have average daily pressures low enough to delay the initiation of drug therapy. These observations permit the development of forecasting models comparing strategies for management of hypertension. Preliminary estimates show that use of ABPM might reduce the number of patients requiring drug treatment over a 6 year period, with reduced cumulative and yearly costs for this interval. Forecasting models using ABPM now should be tested in comprehensive health care systems to determine their effect on overall cost-effectiveness in the management of hypertension.

Ambulatory Care↗
PubMed1993

Effectiveness of nifedipine gastrointestinal therapeutic system for treatment of hypertension: results of the MATH Trial.

Nifedipine gastrointestinal therapeutic system (GITS), a controlled-release delivery system given once a day, was evaluated in a multisite study of mild-to-moderate hypertensive subjects, seated diastolic pressure between 95 and 110 mm Hg, on placebo. Of 1,666 subjects enrolled, 69% were eligible to begin treatment. Therapy with nifedipine GITS was started at 30 mg daily and increased by 30 mg/day each week until there was a response (seated diastolic pressure < 90 mm Hg and a reduction of > or = 10 mm Hg) or until a maximum dose of 180 mg/day was reached. After titration, responders were kept on active treatment for 12 more weeks. Seventy-six percent of those treated responded, and 88% of the responders completed the 12-week phase. Comparisons were made among relevant subgroups. Elderly patients (age > or = 65 years) had a significantly higher response rate at a lower average daily dose, compared with younger subjects. Response rates were > 70% and relatively similar in (a) white and black patients, (b) diabetic and nondiabetic patients, (c) men and women, and (d) normal-weight, over-weight, and obese patients. Nifedipine GITS had no significant effect on fasting serum glucose or cholesterol fractions. Edema and headache were the most often observed adverse effects during treatment. Incidence of the former was related to dose but occurred without evidence of fluid retention (average body weight fell significantly by 1% during treatment). As antihypertensive monotherapy given once a day, nifedipine GITS is effective and well tolerated for a wide spectrum of hypertensive patients.

Administration, Oral↗
PubMed1992

What is the best therapy?

Explore the source record for details and available documents.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

Effects of nifedipine-GITS on left ventricular mass and left ventricular filling.

Sixteen patients with initial diastolic blood pressure greater than or equal to 120 mm Hg were treated for 1 year with extended-release nifedipine [nifedipine-GITS (gastrointestinal therapeutic system)]. Serial changes in left ventricular mass index and associated alterations in left ventricular systolic function, left ventricular filling, plasma renin activity, atrial natriuretic peptide, and catecholamines were evaluated. Blood pressure was significantly reduced from 200 +/- 8/122 +/- 3 mm Hg (mean +/- SEM) to 144 +/- 5/89 +/- 2 mm Hg (p less than 0.0001) at 1 year. Eleven patients (69%) required only nifedipine-GITS for blood pressure control and 5 (31%) required the addition of chlorthalidone. After 6 months, the left ventricular mass index was significantly reduced by 19% from 121 +/- 8 to 96 +/- 7 g/m2 and this reduction was sustained at 1 year. Septal and posterior wall thicknesses were reduced from 13.4 +/- 0.1 to 11.2 +/- 0.04 mm and from 12.8 +/- 0.1 to 10.0 +/- 0.03 mm (p less than 0.001), respectively. Prevalence of left ventricular hypertrophy decreased from 63 to 25%. Left ventricular fractional shortening increased from 34 to 42% (p less than 0.05) and the relationship between fractional shortening and end-systolic stress did not change. Over the year of sustained blood pressure reduction, the peak velocity of early filling increased from 58 to 63 cm/s (p = 0.07), the peak velocity of late filling did not change, and the ratio of late to early peak velocity of left ventricular filling significantly decreased (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Natriuretic Factor↗
PubMed1992

Polycystic ovary syndrome: lack of hypertension despite profound insulin resistance.

It has been hypothesized that insulin resistance and hyperinsulinemia contribute to the development of arterial hypertension. To further investigate this relationship, we compared arterial blood pressure in controls and women with polycystic ovary syndrome (PCO), an insulin-resistant state. Fourteen PCO women and 18 normal control women of similar age, body mass index, and race were studied. Plasma glucose and insulin levels were determined in an oral glucose tolerance test. The insulin sensitivity (SI) index was determined by the minimal model method. Systolic and diastolic blood pressure were measured by 24-h ambulatory monitoring. Left ventricular mass was assessed by echocardiography. The two groups had comparable fasting glucose levels, but the 2-h postload glucose was higher in PCO (8.0 +/- 0.5 vs. 5.6 +/- 0.3 mmol/L; P less than 0.001). Compared to controls, PCO women were significantly more insulin resistant by fasting insulin, 2-h insulin concentrations, and SI (28.3 +/- 6.7 vs. 68.3 +/- 10.0 min-1/nmol.mL; P less than 0.01). Average ambulatory systolic (121 +/- 2 vs. 118 +/- 2 mm Hg) and diastolic (76 +/- 2 vs. 73 +/- 2 mm Hg) blood pressures were similar for PCO and control women. No difference was found in left ventricular mass. Therefore, despite profound insulin resistance and hyperinsulinemia, women with PCO do not have increased arterial pressure or left ventricular mass.

Adult↗
PubMed1991

Normalization of left ventricular mass and associated changes in neurohormones and atrial natriuretic peptide after 1 year of sustained nifedipine therapy for severe hypertension.

Sixteen patients with severe hypertension were treated for 1 year with extended release nifedipine, during which time serial changes in left ventricular mass index and associated alterations in left ventricular systolic function, left ventricular filling, plasma renin activity, atrial natriuretic peptide and catecholamines were evaluated. Mean seated blood pressure (+/- SE) was significantly reduced from 200 +/- 8/122 +/- 3 to 144 +/- 5/89 +/- 2 mm Hg (p less than 0.0001) at 1 year. After 6 months, left ventricular mass index was significantly reduced by 19% from 121 +/- 8 to 96 +/- 7 g/m2 and this reduction was sustained at 1 year. Septal and posterior wall thickness were reduced from 13.4 +/- 0.1 to 11.2 +/- 0.04 mm and from 12.8 +/- 0.1 to 10.0 +/- 0.03 mm (p less than 0.001), respectively. The prevalence of left ventricular hypertrophy decreased from 63% to 25%. Left ventricular fractional shortening increased from 34 +/- 2% to 41 +/- 3% (p less than 0.05) and the relation between fractional shortening and end-systolic stress did not change. Over the year of sustained blood pressure reduction, the peak velocity of early filling increased from 57 +/- 3 to 63 +/- 4 cm/s (p = 0.07), peak velocity of late filling did not change and the ratio of late to early peak left ventricular filling velocity significantly decreased (p less than 0.05). Plasma atrial natriuretic peptide levels, markedly elevated at entry, decreased from 70 +/- 15 to 41 +/- 8 pg/ml at 1 year (p less than 0.05). Plasma renin activity and catecholamine levels were not altered.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Natriuretic Factor↗
PubMed1991

Isolated T-wave abnormalities and evaluation of left ventricular wall motion after nifedipine for severe hypertension.

Rapid reduction of blood pressure by vasodilators in severe hypertensives has been associated with T-wave inversion. The significance of these changes in the absence of chest pain or other manifestations of ischemia is not known. To determine if these T-wave inversions are due to myocardial ischemia, we obtained electrocardiograms and left ventricular wall motion studies (2-D echocardiography) before and 1 h after rapid blood pressure reduction with nifedipine in 23 severe hypertensives. One hour after 10 mg nifedipine blood pressure was markedly reduced from 189 +/- 6/117 +/- 3 (mean +/- SE) to 151 +/- 5/91 +/- 3 mm Hg (P less than .001). New T-wave inversions developed in 6 of 23 (26%) subjects, but blinded evaluation of 2-D echocardiograms revealed no new wall motion abnormalities. Wall motion score, which at pretreatment was abnormal in 11 of 23 patients, improved significantly after nifedipine from 1.4 +/- 0.1 to 1.2 +/- 0.1 (P less than .05). Therefore, rapid and marked reduction of blood pressure with nifedipine is accompanied by a high incidence of asymptomatic T-wave inversions which are not accompanied by left ventricular wall motion abnormalities, suggesting that significant myocardial ischemia did not occur.

Echocardiography↗
PubMed1991

Effect of nifedipine GITS on left ventricular mass and diastolic function in severe hypertension.

Treatment of severe hypertension is beneficial, but reversibility of target-organ damage has not been characterized. Serial studies were performed in 15 patients with severe essential hypertension (age of 56 +/- 3 years, mean +/- SEM) treated for 1 year with 60 to 150 mg/day of continuous-release nifedipine; 3 patients required 50 mg of chlorthalidone/day to lower diastolic blood pressure (BP) to less than 95 mm Hg. Left ventricular (LV) structure and function was evaluated with two-dimensional-directed M-mode echocardiography, digitized from videotape and analyzed blindly. BP was markedly reduced from 194 +/- 8/115 +/- 4 to 146 +/- 4/88 +/- 14 mm Hg (p less than 0.0001) and maintained at this level for 1 year. Posterior wall and septal LV thickness, elevated at entry (12.9 +/- 0.1 and 13.4 +/- 0.1 mm), dropped steadily over 1 year into the normal range (10.0 +/- 0.03 and 11.2 +/- 0.1 mm, p less than 0.001). LV mass index, above 95% for normals at entry, decreased by 19% at 6 months (129 +/- 10 to 104 +/- 7 g/m2, p less than 0.01), and remained at this level at 1 year. LV fractional shortening rose steadily over 1 year from 34 to 42% (p less than 0.02). Atrial natriuretic peptide, which reflects LV filling pressures, was markedly elevated at entry, but was significantly reduced by 6 months (76 +/- 22 vs. 45 +/- 14 pg/ml, p less than 0.05). Sustained reduction of arterial BP with continuous-release nifedipine for 1 year normalizes LV mass, improves LV systolic function, and reduces circulating levels of atrial natriuretic peptide.

Blood Pressure↗
PubMed1991

Ambulatory blood pressure monitoring: is it cost-effective?

The detection and treatment of hypertension can prevent cerebrovascular disease and, to some extent, coronary heart disease. For mild hypertension this process is not efficient because many patients must be treated with antihypertensive medication to benefit only a few. The costs of identification, diagnosis and drug treatment of mild hypertension are significant. These costs have increased recently, in part due to changing patterns of drug selection favoring newer agents. Primary and secondary screening for hypertension has relied on casual blood pressure measurement which has high sensitivity, but low specificity, i.e. many false-positives can be expected. Incorporation of ambulatory blood pressure monitoring into secondary screening has potential for greater specificity by excluding from treatment 20-40% of those initially identified as having mild hypertension. Computer analysis of simulated populations selected for treatment by either casual blood pressure or by use of ambulatory blood pressure monitoring with echocardiography (for borderline cases) demonstrates no difference in calculated life expectancy for the two groups. However, the former strategy selected 23% of the subjects for treatment, while the latter selected 6%. These results imply that appropriate use of ambulatory blood pressure monitoring in secondary screening of mild hypertension may have a significant impact on cost-effectiveness.

Ambulatory Care↗
PubMed1991

Adreno-medullary hypertension: a review of syndromes, pathophysiology, diagnosis, and treatment.

Hypertension may be attributable to various disorders involving the central or peripheral adrenergic (catecholamine) pathways. Pheochromocytoma is the best known of these disorders, but many syndromes mimic the clinical features of this tumor. In adreno-medullary hypertension, cardiovascular tissues are stimulated by activation of alpha or beta adrenergic receptors, or both. Specific diagnosis of adreno-medullary hypertension depends on careful clinical assessment and selection of sensitive and specific biochemical tests for measuring the catecholamines and their principal metabolites in urine or plasma. If such tests indicate the presence of a chromaffin cell neoplasm, accurate localization (imaging) is provided by computed axial tomography (CAT) or magnetic resonance imaging (MRI). Adreno-medullary hypertension is effectively controlled, pharmacologically, by alpha and beta receptor antagonists, which may be given intravenously for emergencies. Excess catecholamine synthesis by pheochromocytomas can be reduced by methyltyrosine. Surgical cure of pheochromocytomas can be expected in most instances, but long-term surveillance for recurrent tumors, some of which may be malignant, is needed. Chemotherapy can reduce the tumor bulk of a malignant pheochromocytoma. Recent use of molecular biology techniques may be helpful in early detection of malignant transformation.

Adrenal Gland Diseases↗
PubMed1990

Nicardipine infusion for postoperative hypertension after surgery of the head and neck.

The therapy of postoperative hypertension (POH) after head and neck surgery was evaluated in a prospective, randomized, double-blind trial. Nicardipine hydrochloride, a Ca channel-blocker for iv use, was compared with placebo. Patients were initially randomized to receive nicardipine infusion or placebo. Those not responding to placebo were given nicardipine infusion on an open basis. Hypertension was significantly better controlled in patients treated with nicardipine infusion compared with placebo (83% vs. 22%, p less than .002). Subsequently, six (86%) of seven of the placebo failures were successfully treated with nicardipine. There were no significant complications in either group. We conclude that the titratable infusion of nicardipine is an effective and safe method for the control of POH after surgery of the head and neck. Further studies are now warranted comparing nicardipine with other drugs currently used to treat this condition.

Blood Pressure↗
PubMed1990

Sustained calcium channel blockade in the treatment of severe hypertension. A two year experience.

Thirty-nine patients with severe hypertension (diastolic blood pressure greater than 120 mm Hg) predominantly drawn from an inner-city population were placed on nifedipine gastrointestinal therapeutic system (GITS) for long-term treatment to achieve a sustained diastolic blood pressure less than 95 mm Hg. Fourteen patients failed to complete 6 months of therapy. For the 25 who remained in treatment for 6 months or more, systolic/diastolic blood pressure reductions were 62 +/- 5/40 +/- 2 mm Hg at 6 months; for those followed more than 12 months (n = 18), 58 +/- 7/37 +/- 3 mm Hg at 12 months; and for those followed more than 18 months (n = 11), 54 +/- 6/37 +/- 3 mm Hg at 18 months. Overall, 75% of these severely hypertensive patients were controlled with nifedipine GITS alone; 80% required 90 mg/day or more. During the two years of observation, no patient had a severe medical event, and 44% of those who entered remain in treatment. Left ventricular hypertrophy, as determined by echocardiography, diminished significantly during the course of treatment. These results indicate nifedipine GITS is well-tolerated and effective as monotherapy in the treatment of severe hypertension.

Adult↗