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David A Calhoun

Publications and source records attributed to David A Calhoun.

25 records · Page 2Linked to original sources
PubMed2003

Efficacy of low-dose spironolactone in subjects with resistant hypertension.

BACKGROUND: Previous reports have demonstrated the antihypertensive efficacy of high doses of spironolactone in subjects with primary aldosteronism and, to a lesser degree, subjects with resistant hypertension. METHODS: In current analysis, we examined the antihypertensive benefit of adding low-dose spironolactone to multidrug regimens that included a diuretic and an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) in subjects with resistant hypertension with and without primary aldosteronism. Subjects referred for resistant hypertension were evaluated with an early morning plasma renin activity, 24-h urinary aldosterone and sodium during a high dietary salt ingestion. The diagnosis of primary aldosteronism was confirmed with a renin activity <1.0 ng/mL/h, urinary aldosterone >12 mug/24 h and urinary sodium >200 mEq/24 h. After biochemical evaluation, spironolactone (12.5 to 25 mg/d) was added to each subject's antihypertensive regimen. If blood pressure (BP) remained uncontrolled, the dose of spironolactone was titrated up to 50 mg/d. Follow-up BP was determined at 6 weeks, 3 months, and 6 months. RESULTS: A total number of 76 subjects were included in the analysis, 34 of whom had biochemical primary aldosteronism. Low-dose spironolactone was associated with an additional mean decrease in BP of 21 +/- 21/10 +/- 14 mm Hg at 6 weeks and 25 +/- 20/12 +/- 12 mm Hg at 6-month follow-up. The BP reduction was similar in subjects with and without primary aldosteronism and was additive to the use of ACE inhibitors, ARBs, and diuretics. CONCLUSIONS: We conclude that low-dose spironolactone provides significant additive BP reduction in African American and white subjects with resistant hypertension with and without primary aldosteronism.

Adult↗
PubMed2003

Prevalence of renal artery stenosis in high-risk veterans referred to cardiac catheterization.

OBJECTIVE: The prevalence of atherosclerotic renal artery stenosis (RAS) varies depending on patient selection with no specific guidelines on indications for selective renal angiography in patients referred for coronary angiography. The goal of this study is to determine the prevalence and predictors of renal artery stenosis in hypertensive veterans referred for coronary angiography. DESIGN: Prospective study. SETTING: Tertiary care veterans' administration facility in the USA. PATIENTS, PARTICIPANTS: A total of 90 veterans referred for coronary angiography with an initial ascending aortic pressure > 135 mmHg. INTERVENTIONS: Selective renal angiography was performed following coronary angiography. RESULTS: We found that 28% of the patients had single RAS (> or = 50% stenosis), while 16% had single RAS > or = 70% stenosis, 10% had bilateral RAS >or = 50% and 6% had bilateral RAS > or = 70%. Significant positive univariate predictors of RAS (> or = 50%) were age, peripheral vascular disease (PVD), creatinine level (Cr) and myocardial infarction. Significant multivariate predictors of RAS (> or = 50%) were age > 65 years [relative risk (RR), 3.6; 95% confidence interval (CI), (1.2-10.6)], PVD [RR 3.2, 95% CI (1.1-9.1)] and Cr > 1 mg/dl [RR 4.9, 95% CI (1.53-15.9)]. No complications related to renal angiography were noted. CONCLUSIONS: Selective renal angiography during routine coronary angiography in hypertensive veterans with coronary artery disease is safe and uncovers RAS in many older patients with PVD and renal insufficiency.

Aged↗
PubMed2002

Resistant hypertension.

Recent clinical trials suggest that resistant hypertension is increasingly common. In the majority of patients, uncontrolled hypertension is due to persistent elevation of the systolic blood pressure. Older age and obesity are associated with poor blood pressure control. Other contributing factors include severity of the underlying hypertension and renal insufficiency. Poor patient adherence is thought be a common cause of medication resistance. Exogenous substances such as nonsteroidal anti-inflammatory drugs, oral contraceptives, and sympathomimetic agents can interfere with treatment. The prevalence of secondary causes of hypertension increases with age, especially atherosclerotic renal artery stenosis. Recent reports suggest that primary aldosteronism may be the most common secondary cause of hypertension. It should be considered in all patients with resistant hypertension. Effective treatment of resistant hypertension requires identification and reversal of contributing factors and/or secondary causes of hypertension. Pharmacologic therapy should utilize combination therapy, including a long-acting diuretic.

Age Factors↗
PubMed2002

Drugs targeting the renin-angiotensin-aldosterone system.

Effective antihypertensive therapy has made a major contribution to the reductions in the morbidity and mortality of cardiovascular disease that have been achieved since the 1960s. However, blood-pressure control with conventional drugs has not succeeded in reducing cardiovascular disease risks to levels seen in normotensive persons. Drugs that inhibit or antagonize components of the renin-angiotensin-aldosterone system are addressing this deficiency by targeting both blood pressure and related structural and functional abnormalities of the heart and blood vessels, thus preventing target-organ damage and related cardiovascular events.

Angiotensin II↗
PubMed2002

Hyperaldosteronism among black and white subjects with resistant hypertension.

Recent reports suggesting that the prevalence of primary hyperaldosteronism may be higher than historically thought have relied on an elevated plasma aldosterone concentration/plasma renin activity ratio to either diagnose or identify subjects at high risk of having primary hyperaldosteronism and have not included suppression testing of all evaluated subjects. In this prospective study of 88 consecutive patients referred to a university clinic for resistant hypertension, we determined the 24-hour urinary aldosterone excretion during high dietary salt ingestion, baseline plasma renin activity, and plasma aldosterone in all subjects. Primary hyperaldosteronism was confirmed if plasma renin activity was <1.0 ng/mL per hour and urinary aldosterone was >12 microg/24-hour during high urinary sodium excretion (>200 mEq/24-hour). Eighteen subjects (20%) were confirmed to have primary hyperaldosteronism. The prevalence of hyperaldosteronism was similar in black and white subjects. Of the 14 subjects with confirmed hyperaldosteronism who have been treated with spironolactone, all have manifested a significant reduction in blood pressure. In this population, an elevated plasma aldosterone/plasma renin activity ratio (>20) had a sensitivity of 89% and a specificity of 71% with a corresponding positive predictive value of 44% and a negative predictive value of 96%. These data provide strong evidence that hyperaldosteronism is a common cause of resistant hypertension in black and white subjects. The accuracy of these results is strengthened by having done suppression testing of all evaluated subjects.

Adult↗
PubMedDate not supplied

Use of aldosterone antagonists in resistant hypertension.

Resistant hypertension is defined as an elevated blood pressure in spite of treatment with 3 different antihypertensive agents. The prevalence of resistant hypertension is unknown, but recent cross-sectional analyses and hypertension outcome studies suggest it is a common clinical problem and will become even more so with an aging and increasingly heavy population. Secondary causes of hypertension are common in patients with resistant hypertension, in particular, obstructive sleep apnea and hyperaldosteronism. Treatment of resistant hypertension is predicated upon identification and reversal of secondary causes of hypertension, as possible, and effective use of multidrug regimens. Recent clinical studies indicate that aldosterone antagonists, spironolactone and amiloride, provide significant additional blood pressure reduction when added to treatment regimens of patients with resistant hypertension. Both agents are generally well tolerated. Hyperkalemia is an uncommon complication of aldosterone antagonists, but it can occur; therefore, biochemical monitoring is necessary, particularly in high-risk patients.

Blood Pressure↗