FODOR JG. Hypertenzia u starých ľudí. Cardiol 2003;12(1):28–32
Mohutná databáza poskytuje veľké množstvo dôkazov, že nefarmakologická a farmakologická liečba starých ľudí s vysokým tlakom môže zabrániť alebo oddialiť vznik závažných kardiovaskulárnych príhod. Pri liečbe starých ľudí s hypertenziou treba brať do úvahy špecifičnosť výberu liekov, komorbiditu, tendenciu k posturálnej hypotenzii. Vo väčšine prípadov bude potrebné podávať viac ako jeden liek, aby sa dosiahla prijateľná kontrola vysokého tlaku. Preto by mal byť postup „začni nízkou dávkou, pokračuj pomaly“, čo znamená postupne titrovať lieky, kým sa nedosiahnu cieľové hladiny s minimálnymi vedľajšími účinkami. Blokátory receptorov angiotenzínu II by mali zohrávať kľúčovú úlohu pri liečbe starých ľudí s hypertenziou.
Kľúčové slová: hypertenzia – starí ľudia – epidemiológia – patofyziológia – rizikové faktory – antihypertenzívne agens

The Canadian Heart Health Survey (1) ascertained that among people in the age group 65 – 74 years, 56% of males and 58% of females were hypertensive. This survey defined hypertension as systolic blood pressure (SBP) > 140 mmHg or diastolic blood pressure (DBP) > 90 mm Hg or current treatment with a prescription for anti-hypertension medication or non-pharmacological treatment of blood pressure (weight control or sodium/salt restriction).

The problem of hypertension in the elderly will steadily increase in importance in the near future. As Table 1 shows, during the next 20 years, there will be a 6 % increase in the number of Canadian elderly, with a corresponding increase in numbers of hypertensive patients requiring medical care. Doubtless this demographic trend is occurring also in the Slovak Republic. Apart from the demographic changes, improved survival of hypertensives with co-morbid conditions would further swell this patient pool.

Elderly hypertensives have reduced distension and elasticity in the large capacitance arteries. This result is increased pulse wave velocity and early return of pulse wave reflection in systole. Thus the blood pressure has a tendency to fluctuate, creating an increased stress on the vascular system. These patients usually have lower intravascular volume, lower renal blood flow, and plasma renin activity and higher peripheral vascular resistance.

Because the elderly have decreased baroreceptor responsiveness than younger individuals they are also more likely to have asymptomatic postural changes. Postural hypotension was found in 10.4% respondents in the Systolic Hypertension in the Elderly Program (SHEP) at 1 minute after rising from a seated position (2). It is therefore likely that a higher proportion would manifest postural hypotension after rising from supine position. The potential for orthostatic hypertension should be kept in mind when initiating antihypertensive treatment and choosing dosages in elderly patients.

Not so long ago there were widely held views that older patients required higher blood pressure to perfuse narrowed and stiffened arteries. As a matter of fact textbooks published in the mid 70s defined hypertension in those above age 65 as BP 210/110 mm Hg or more (3) and stated that “blood pressure level of 180/100 is less abnormal and menacing at the age of 70 than at 45” (4).

Today we have a robust database of information documenting that total mortality, both from coronary disease and from stroke, is much higher among elderly hypertensives than in comparable middle-aged populations. In particular the risk of cerebrovascular events associated with elevated systolic blood pressure is now well documented.

While the above analysis slightly favored PP over SBP in predicting CHD, a recent study found that after adjustment for all potential confounders, SBP was a better predictor of CV events than DBP or pulse pressure (12). There is however one caveat. The evidence for a strong positive association between increased SBP and greater CV risk is not available for the very old (i.e. people over age of 80). Starr et al. (13) observed that the survival after 4 years among 603 men and women aged 70 – 88 was better in those with initial casual SBP below 150 mm Hg than in those with higher BP levels.

Is treatment of hypertension in elderly beneficial and, if so, what are the target values?

There have been several large trials showing the beneficial effect of therapy in elderly hypertensive patients [Australian (14), EWPHE (15), Cooper and Warrender (16), STOP (17), STOP-2 (18), MRC (19), SHEP (20), Syst-Eur (21), Syst-China (22), HDFP (23), INSIGHT (24)]. All of these trials documented a significant reduction (range ~17 – 40%) in the incidence of major cardiovascular events in the active treatment arm.

The only randomized clinical trial addressing the issue of treatment targets has been the Hypertension Optimal Treatment (HOT) study (25). The trial addressed two issues: i) how far should pressure be lowered and, ii) is there any benefit to adding low-dose (75 mg) aspirin to the antihypertensive treatment?

A total of 18, 790 patients, both men and women aged 50 – 80 years were randomized to one of three diastolic pressure ranges (below 80, 80 – 85 or 86 – 90 mmHg). The trial arms were further divided into either placebo or active aspirin groups. Based on intention-to-treat analysis of the primary endpoint, no difference was seen between the three groups. However, when data from all three groups were pooled, the optimum effect on major cardiovascular events was seen in patients with DBP of 83 mm Hg and systolic pressures of 138.5 mm Hg.

At 1 year the percentage of patients at target in the elderly subgroup was higher in all three groups. Patients with heart disease and diabetes mellitus benefited most if their diastolic pressures were reduced to below 80 mm Hg.

Based on this evidence the Canadian Hypertension Working Group (26) recommend reducing blood pressure to less than 140/90 in most patients including the elderly. The goal for patients with diabetes or renal dysfunction is less than 130/80 mm Hg.

Salt restriction and weight reduction are efficacious interventions in the elderly (27). It is desirable to reduce the salt intake from the average Canadian daily intake of 8 – 12 g/daily to less than 5 g/day. The average daily salt intake is probably similar in the Slovak Republic. We must keep in mind however that more than 80% of salt intake is involuntary and is consumed in industrially processed foods. For the patient to achieve the required reduction of the dietary sodium intake can be a difficult task. Clearly, in the future reduction of the population’s salt intake would be hard to implement without cooperation of the government and food industry.

The present Canadian Slovak project of introducing a “logo” for heart healthy food products has as one of its aims a promotion of low salt products.

We also have to be aware of the fact that most strategies trying to achieve a permanent weight reduction fail.

Since effectiveness of non-pharmacological intervention is usually unsatisfactory, effective pharmacological treatment should not be postponed. However, if the patient succeeds in reducing excessive body weight and reducing salt intake, the drug therapy can be modified or even withdrawn.

For uncomplicated hypertension without contraindications, low-dose thiazide diuretics (e.g. 12.5 – 25 mg hydrochlorthiazide) or long-acting dihydropyridine calcium channel antagonists are recommended for first line therapy. Since it is possible for even low dose diuretics to lead to hypokalemia (potassium concentration < 3.5 mEq/L), close monitoring is necessary and potassium-sparing diuretics or potassium supplements for those at risk of developing hypokalemia may be required (7% hypokalemia in SHEP study active treatment group, and risk of CV event ~50% lower in active treatment group with normal serum potassium). Based on data from the Syst-Euro and Syst-China trials and the INSIGHT study, a long acting dihydropyridine calcium channel blockers may be a substitute first line therapy for patients with ISH who cannot take a diuretic or who show poor respond to diuretic therapy.

ACE inhibitors should be considered as alternative therapy when diuretics or calcium-channel blockers are ineffective, contraindicated or not tolerated and in cases of recent MI. ACE inhibitors have been shown to be comparable to diuretics and calcium antagonists in reducing blood pressure and favourably affect cardiovascular outcomes in the elderly. Angiotensin II receptor antagonists (ARB s) are well tolerated and produce clinically significant reductions in blood pressure (28, 29), with lower incidence of treatment-related cough. However up until recently there was no evidence yet as to their effects on incidence of CV outcomes in this age group.

This year results of two important trials were released. One is the LIFE study, (30) the other is the SCOPE study (31).

The Losartan Intervention For Endpoint reduction in hypertension study (30) was a double-blind, randomized, parallel-group trial in more than 9000 patients with essential hypertension and electrocardiographic evidence of left-ventricular hypertrophy, who were assigned to once-daily losartan-based (n = 4605) or atenolol-based (n = 4588) therapy. The trial was designed to last for at least 4 years, and until 1040 patients had a primary cardiovascular event (death, MI, stroke).

The average age of the respondents was 66.9 years, and therefore this trial can be considered as a trial of elderly hypertension.

Results showed that treatment with losartan has reduced the incidence of stroke and new-onset diabetes by 25% as compared to beta-blocker therapy with atenolol. There was a significant difference between study groups in the primary composite endpoint that was driven by the significant difference in stroke; the rates of MI and cardiovascular mortality were not significant between the two. These results are particularly interesting, because both losartan and atenolol provided similar blood pressure lowering effects. Thus the benefits of losartan therapy are obviously stroke prevention due to effects beyond just lowering blood pressure. Another important benefit has been the significantly reduced incidence of new onset diabetes by 25%.

The other important trial highlighting the effect of Angiotensin II type I receptor blockers in treating elderly hypertensives is the SCOPE study (31).

Patients were randomized on candesartan 8 mg or HCTZ 12.5 mg. When necessary the drugs were titrated upward and other drugs could be added if target BP levels were not achieved.

In this “head to head” comparison the candesartan therapy proved to be not only as effective in reducing cardiovascular events as therapy with thiazides, but proved to be significantly better in preventing non-fatal cerebrovascular strokes (-28%). Another important observation in the SCOPE study was the beneficial effect of the candesartan therapy on preventing decline of cognitive function in a subgroup of patients.

The SCOPE study complements the LIFE study in confirming the beneficial effect of ARBs in treating not only high-risk elderly hypertensives but also those with mild hypertension and with relatively low global cardiovascular risk.

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