Hypertension in the elderly with a special focus on treatment with angiotensin-converting enzyme inhibitors and calcium antagonists

[Serum potassium levels and long-term mortality in the elderly with hypertension]

There is increasing evidence that small variations within the normal range (3.5-5mEq/L) of potassium are associated with mortality.

OBJECTIVE

To determine whether there is an association between serum potassium level (sK) and mortality in a cohort of elderly hypertensive patients.

PATIENTS AND METHODS

A retrospective, observational study was conducted on patients who had sK levels available in a period of clinical stability during their recruitment between January and April 2006 and followed-up for 10 years. The study obtained a total of 62 stable patients, with a mean age of 82.19±6 years (range 69-97), with 74.2% women, 33.9% diabetics, 20.3% with a history of heart failure, Ischaemic heart disease was observed in 19.4% and 44.3% received Angiotensin Converting Enzyme (ACE) inhibitors. An analysis was performed on the mortality rate during the 10 year period. The statistics were performed using the SPSS15.0 package.

RESULTS

There were 49 deaths. The sK had a normal distribution. Baseline mean sK levels and median were 4.45±0.5mEq/L (range 3.1-5.5 mEq/L). Baseline sK levels were significantly higher in diabetic patients and patients on ACE inhibitors. The patients that died had higher sK levels (4.53±0.49mEq/L versus 4.14±0.40mEq/L, P=.011). Survival estimated using Kaplan Meier showed that patients with sK levels higher than the median and P75 had higher mortality.

CONCLUSIONS

In our study, sK levels greater than 4.45mEq/L were associated with mortality. When selecting antihypertensive treatment in hypertensive elderly patients,, the use of ACE inhibitors should be assessed individually, with close monitoring at sK levels and try to keep them in the lower limit of the normal range (<4.45 mEq/L).

Reversal of pathophysiologic changes with long-term lisinopril treatment in isolated systolic hypertension

The purpose of this study was to evaluate in a prospective, double-blind, placebo-controlled study the effect of long-term (2-year) lisinopril treatment on cardiovascular end-organ damage in patients with previously untreated isolated systolic hypertension (ISH). All patients with ISH were derived from a population screening program. End-organ damage measurements, done initially and after 6 and 24 months of treatment, included measurements of aortic distensibility and echocardiographic left ventricular mass index (LVMI) and diastolic function. Blood pressure was measured by office and ambulatory measurements. Of the 97 subjects with ISH selected from the screening, 62 (30 lisinopril) completed the study according to protocol. Office blood pressure decreased in both groups, but ambulatory results significantly decreased with lisinopril-treatment only. Aortic distensibility increased significantly with lisinopril, as opposed to a decrease in placebo-treated subjects. The main effect of increased distensibility occurred between 6 and 24 months, whereas ambulatory blood pressure changed mainly in the first 6 months of treatment. LVMI decreased in both treatment groups, with a significantly higher reduction in lisinopril-treated subjects. Left ventricular diastolic function showed no significant changes in either group. The vascular pathophysiologic alterations of ISH-a decreased aortic distensibility-can be improved with long-term lisinopril treatment, whereas values deteriorate further in placebo-treated subjects. These results, in one of the first studies including subjects with previously untreated ISH only, indicate that lisinopril treatment might favorably influence the cardiovascular risk of ISH.

Nifedipine-induced inhibition of parasympathetic-mediated vasodilation in the orofacial areas of the cat

In anesthetized cats, we 1) compared the effects of antihypertensive agents (nifedipine, clonidine, phentolamine, propranolol, and nitroprusside) on the parasympathetic vasodilations elicited by lingual nerve (LN) stimulation in the lower lip and tongue and 2) investigated the mechanisms underlying the inhibitory effect of nifedipine on parasympathetic lower lip vasodilation. At the doses used, each antihypertensive agent reduced systemic arterial blood pressure by approximately 20 mmHg; however, the parasympathetic vasodilation elicited by LN stimulation was significantly reduced only by nifedipine. This inhibitory effect of nifedipine was not seen when LN was stimulated during ongoing repetitive stimulation of the superior cervical sympathetic trunk at 1-Hz frequency. This suggests that the ability of lip and tongue blood vessels to relax to parasympathetic stimulation is not directly impaired by this calcium channel blocker and that the inhibitory effects of nifedipine seen here probably resulted from an action on postsynaptic sites in vascular smooth muscle that caused a reduction in preexisting sympathetic vasoconstrictor tone (by inhibiting calcium influx into the vascular smooth muscle cell).

Sensitive high-performance liquid chromatographic determination of nifedipine in cat plasma following improved sample treatment

A simple, easy and accurate reversed-phase high-performance liquid chromatographic method is described for the determination of nifedipine in cat plasma. The procedure involves extraction of nifedipine from plasma using a Sep-Pak C18 cartridge and ultraviolet detection at 350 nm. The present method provides the required reproducibility and sensitivity for the determination of low concentrations of nifedipine without interference from plasma components or photodegradation products. The method was validated over the range 1-50 ng/ml nifedipine. Accuracy and precision were, respectively, 97% or more and 5% or less over the concentration range examined. The minimum quantifiable concentration of nifedipine was found to be 1 ng/ml.

Effect of quinapril and triamterene/hydrochlorothiazide on cardiac and vascular end-organ damage in isolated systolic hypertension

We compared, in a prospective double-blind randomized study, the effect of the angiotensin-converting enzyme inhibitor quinapril (QUI) with that of triamterene/hydrochlorothiazide (THCT) treatment on cardiovascular end-organ damage in subjects with untreated isolated systolic hypertension (ISH). End-organ damage measurements, performed initially and after 6 and 26 weeks of treatment, included echocardiographic determination of left ventricular mass index (LVMI) and of diastolic function and measurement of aortic distensibility and peripheral vascular resistance. Blood pressure was significantly reduced in the 44 subjects (21 QUI, 23 THCT) completing the study. Both LVMI and aortic distensibility had changed at 6 weeks, with comparable improvements in both groups. LV diastolic function showed overall no significant changes, although patterns of early filling did differ between the two drug groups. Peripheral vascular resistance appeared to increase between 6 and 26 weeks in THCT subjects only, along with a decreased aortic distensibility. Blood pressure and LV mass were rapidly and markedly reduced in both treatment groups of ISH subjects, paralleled by an improvement of aortic distensibility. In interpreting these results, the pathophysiologic alterations in ISH need to be taken into account, because these differ strongly from those in diastolic hypertension. Results of LV diastolic function and peripheral vascular resistance were less clear but appear to show less favorable changes in the THCT subjects treatment group.

Individual assessment of antihypertensive response by self-starting cumulative sums

A self-interpreted control chart, on an individualized basis, assesses the effect of a switch from beta-blockers to an angiotensin-converting enzyme (ACE)-inhibitor in a patient with occasional blood pressure (BP) excess. In dense and long data series, the BP and heart rate (HR) of this patient respond to the change in treatment by the test criterion of a self-starting Cumulative Sum (cusum), which reaches values outside a decision interval with a lowering of BP and an increase in HR and vice versa, at least for BP, after treatment cessation. Thereafter, minimal sampling requirements are sought in the same data by applying the same control chart approach to decimated data. Skeleton sampling schemes in a system of chronobiologic self-analysis and interpretation of manually recorded data obtained at strategically placed times (established on the basis of data decimations) could complement control charts that are used on a home computer or preferably would be built into the output of ambulatory monitors used at the outset as a minimum and routinely as an optimum.

Hypertension in Elderly Persons

OBJECTIVE

To provide an overview of the prevalence of hypertension in the elderly population and discuss the advantages and disadvantages of various classes of antihypertensive drugs.

METHODS

We review the published clinical trials on treatment of elderly patients with hypertension and describe adverse reactions that are frequently associated with antihypertensive therapy.

RESULTS

On the basis of the standard for control of hypertension established by the National Health and Nutrition Examination Survey for 1988-1991 (140/90 mm Hg), almost 75% of all African-Americans and 50% of all whites 60 to 74 years of age have hypertension. If modifications in lifestyle (such as weight reduction and increase in exercise) do not normalize blood pressure levels, drug therapy is warranted. Meta-analyses of major trials of treatment of hypertension have revealed significant reductions in cardiovascular-related mortality and stroke, and available data indicate that prudent use of antihypertensive agents is associated with an acceptable degree of toxicity. Low-dose thiazide diuretics and b-blockers remain the agents of choice.

CONCLUSION

Several trials have substantiated the effectiveness of treatment of hypertension in elderly subjects. Drug therapy should be initiated at low doses, and careful follow-up should monitor for adverse effects.

ACE inhibitors. Differential use in elderly patients with hypertension

High blood pressure (BP) in the elderly must not be ignored as a normal consequence of aging. The criteria for the diagnosis of hypertension and the necessity to treat it are the same in elderly and younger patients. The aim of treatment of elderly hypertensive patients is to decrease BP safely and to reduce risk factors associated with cerebrovascular, cardiovascular and renal morbidity and mortality. The treatment of elderly hypertensive patients should be adjusted according to the needs of the individual, based upon age, race, severity of hypertension, co-existing medical problems, other cardiovascular risk factors, target-organ damage, risk-benefit considerations and costs. In addition to the elevated BP, other cardiovascular risk factors include smoking, glucose intolerance, hyperinsulinaemia, dyslipidaemia, hypercreatininaemia, peripheral vascular disease, left ventricular hypertrophy, and microalbuminuria (or albuminuria). Thus, the choice of initial antihypertensive therapy in elderly hypertensive patients should be based not only on the expected response, but also on the effects of therapy on lipid, potassium, glucose and uric acid levels, and left ventricular anatomy and function. Co-existing medical conditions (such as asthma, diabetes mellitus, heart failure, renal failure, gout, coronary artery disease, hyperlipidaemia and peripheral vascular disease) are major determinants for the selection of antihypertensive medications. With previous therapies (diuretics, beta-blockers, etc.), good BP control in the elderly was associated with clear and statistically significant reductions in stroke-related morbidity and mortality, but the overall effects on cardiovascular and renal complications of hypertension was either more variable or less obvious. Angiotensin converting enzyme (ACE) inhibitors are not only efficacious antihypertensive agents in the elderly, but also appear promising in counteracting some of the cardiovascular and renal consequences of hypertension. They are well tolerated and have a relatively low incidence of adverse effects. ACE inhibitors possess ancillary characteristics that are potentially beneficial for many elderly patients, including reduction of left ventricular mass, lack of metabolic and lipid disturbances, no adverse CNS effects, no risk of induction of heart failure, and a low risk of orthostatic hypotension. Since ACE inhibitors may improve perfusion to the heart, kidney and brain, they are well worth considering for the treatment of elderly patients with hypertensive target organ damage, especially in patients with heart failure, and diabetic patients with early nephropathy.

A multi-center analysis of the use of enalapril and lisinopril in elderly hypertensive patients

OBJECTIVE

To evaluate the clinical use and adverse effects of enalapril and lisinopril in elderly hypertensive subjects.

DESIGN

A multi-center, retrospective, drug use evaluation survey.

SETTING

Ambulatory care clinics at 14 VA and 14 academic medical centers.

PATIENTS

422 elderly (> 60 years of age) patients with hypertension and no clinical evidence of congestive heart failure.

INTERVENTION

At least 3 consecutive months of anti-hypertensive therapy with either enalapril or lisinopril.

MEASUREMENTS

Blood pressure, serum creatinine, serum potassium, concomitant disease states, concurrent medications, and documentation of any adverse event that might be related to ACE inhibitor therapy.

RESULTS

There were no significant differences in systolic and diastolic blood pressures, serum creatinine, or serum potassium between enalapril- and lisinopril-treated patients at baseline and after 3 months of therapy. Both treatments resulted in a significant reduction in diastolic blood pressure. There was no significant difference in the incidence of adverse effects between the two treatments. Significantly more patients were dosed on a twice daily regimen of enalapril than lisinopril.

CONCLUSION

The data from this retrospective study confirm the safe and effective use of enalapril and lisinopril, two long-acting ACE inhibitors, in elderly hypertensive patients.

Treating isolated systolic hypertension in the elderly

OBJECTIVE

To review the prevalence, pathophysiology, vascular risk, and treatment of isolated systolic hypertension (ISH) in the elderly.

DATA SOURCE

A MEDLINE search of the English language literature was performed to identify pertinent literature. Key search terms were hypertension, systolic, and elderly.

STUDY SELECTION

All studies available evaluating drug therapy for ISH or hypertension in the elderly as well as review articles discussing the prevalence, pathophysiology, and treatment of ISH were selected.

SYNTHESIS

ISH occurs commonly in the elderly and is associated with increased risk for cardiovascular and cerebrovascular disease. Although the mechanism for ISH in the elderly is not completely understood, the primary factor is believed to be a reduction in arterial compliance. Results of the Systolic Hypertension in the Elderly Program demonstrated that control of ISH using a diuretic alone or in combination with a beta-blocker significantly reduced the incidence of strokes and cardiovascular events. In this trial, drug therapy was found to be safe and generally well tolerated by the elderly. Newer antihypertensive agents such as the calcium-channel blockers and angiotensin-converting enzyme (ACE) inhibitors have also been shown to effectively lower SBP in the elderly, but the effects on long-term morbidity and mortality are not yet known.

CONCLUSIONS

ISH is an important risk factor for vascular disease in the elderly. Accurate diagnosis and effective drug treatment can result in significant reductions in the risk of cardiovascular and cerebrovascular events. Based on the available trial data, diuretics appear to be the drugs of first choice unless there are contra-indications. If combination drug therapy is required, beta-blockers should be considered although their contribution to vascular risk reduction remains less clear. Additional studies are needed to determine the long-term benefits and risks of alternative antihypertensive agents such as calcium-channel blockers and ACE inhibitors.