ABPM ambulatory blood pressure monitoring
BP blood pressure
HBPM home blood pressure monitoring
Excessive decrease of BP is a serious problem among the elderly, including those undergoing hypertension treatment. Some well-known predictors of hypotension are diabetes mellitus, a medical history of stroke, severe heart failure, chronic kidney disease, as well as frailty and intensive blood pressure control . In this article we will mostly discuss transient episodic hypotension, both its causes and effects which differ from those of lasting hypotension (from several hours to several days).
The condition of transient hypotension in hypertensive patients is understudied, leaving physicians in need of more practical advice on this subject, such as:
- What blood pressure level in an elderly patient should qualify as hypotension?
- Are clinical manifestations of hypotension significant?
- How should we diagnose and interpret decreased blood pressure episodes that are unrelated to orthostatic, postprandial and exercise stress hypotension?
- What is the best treatment strategy for elderly patients with transient hypotension?
Hypotension criteria have not yet been clearly defined for the elderly. The parameters for hypotension as proposed by D. Owens and E.T. O’Brien, are 108/68 mmHg and 87/50 mmHg for daytime and night-time, respectively, for men ≥50 years old, and daytime 90/68 mmHg and night-time 84/49 mmHg, for women of the same age. The data was obtained in a population-based study, the Allied Irish Bank (AIB) phase two study, through 24-hour blood pressure monitoring . A key limitation of this and similar approaches is that they do not specify the hypotension criteria for the elderly and overlook other serious health issues which impact the patient’s autoregulation mechanism of blood flow to the vital organs. It is therefore obvious that a BP measurement alone is not sufficient to qualify the patient’s condition as morbid. Expediently, defining hypotension as any level of BP lower than normal for a given individual, however advisable that approach may seem, may not be definitive in all situations.
Some clinical trials register hypotension when it is the primary cause for hospital admission and is featured as the diagnosis in the medical record. This is a case of symptomatic hypotension . It is the occurrence of this condition which is reported by clinical trials. Such an approach clearly does not address numerous hypotension episodes including those which cause much discomfort to patients. Another extensive meta-analysis estimated the frequency of orthostatic hypotension in relation to the intensity of antihypertensive treatment. It found that lower target levels of arterial pressure are not associated with more frequent orthostatic hypotension episodes . However, a significant limitation of the cited meta-analysis is that it registered orthostatic reactions on account of the orthostatic assessment performed during the visit, regardless of any symptoms accompanying the BP decrease. Additionally, the research used data obtained by different assessment techniques.
Pathogenesis – symptomatic and asymptomatic hypotension
The difference between symptomatic and asymptomatic hypotension is not clear. Health care manuals do not offer a comprehensive agreed-upon definition of symptomatic hypotension. Symptomatic and asymptomatic hypotension appear to have different significance and implications. The cerebral and cardiac signs that manifest impaired circulation in these organs can be due to the insufficiency of blood flow, the autoregulation mechanisms, essential vascular malformation or a combination of these elements. Thus, the same low level of BP may be accompanied by cardio- and cerebrovascular symptoms in one case and preclude them in the second case. This means that there is either a dysfunction of autoregulation mechanisms, or that a vascular disease is present.
In addition, these symptoms also reflect the probability of organ (brain, heart) damage. Obviously, symptomatic episodes of hypotension are a more negative phenomenon. According to the data we obtained, patients without a myocardial infarction or stroke in their past medical history develop hypotension symptoms at ≤100 mmHg systolic BP decrease on average. In contrast, patients with previously recorded cardiovascular events report malaise at higher systolic BP levels, which appears to be associated with a deterioration in blood flow in vital organs, even for minor BP fluctuations .
In everyday practice, cardiologists quite often come across hypotension accompanied by negative symptoms. According to an observational study, orthostatic hypotension occurs in about 3-26% of patients with hypertension, the likelihood increases with age. Orthostatic hypotension is associated with cognitive dysfunction, deterioration of quality of life and the risk of death. The emergence of orthostatic hypotension is predictable in patients with untreated hypertension, isolated systolic hypertension, diabetes mellitus and renal dysfunction .
About 20% of patients with essential hypertension and coronary heart disease suffer from postprandial hypotension . This is associated with an increased risk of stroke and coronary events, as well as total mortality . Little is known about the occurrence rate of exercise stress hypotension in elderly subjects. However, it seems plausible that it is not connected with vasomotor tone dysregulation but is a consequence of transient myocardial ischemia and short-term violation of the cardiac pumping function. Veteran athletes with hypertension often experience problems with a post-workout BP increase combined with normal BP levels when measuring at home .
Clinical trials suggest some generalisations about hypotension caused by hypertension management, but the statistics do not reflect all the cases. In our experience and according to our research, patients with pronounced atherosclerotic changes of the vascular wall are likely to experience hypotension regardless of the hypertension management.
Transient symptomatic hypotension occurs commonly (up to 70%) both in association with regular medication and in the absence of constant hypertension management. Thus, medication used in therapy is a highly unlikely cause for hypotension. It is noteworthy that in most hypertension patients the causes of symptomatic episodes of hypotension remain unrecognised and are not associated with the above-mentioned conditions. We have found that episodes of symptomatic hypotension which have no explicit cause occur in 40-70% of the hypertensive patients, 2-3 times a month on average. In patients with cardiovascular diseases, they occur more often and may be predictive of the risk of cerebrovascular and cardiovascular incidents .
Altogether, it is crucial to register symptomatic hypotensive episodes and patient enquiry is essential to this step. If BP decreases below the usual level (usually more than 15-20 mmHg) against the constant BP control and is accompanied by discomfort in the head and/or chest and a general malaise lasting more than 5-10 minutes, the physician should be alerted. Home blood pressure monitoring (HBPM) and ambulatory blood pressure monitoring (ABPM) with a detailed diary can also be used to diagnose symptomatic hypotensive episodes.
What is the physician’s best course of action when the patient reports transient hypotension episodes?
How should we deal with intensive blood pressure control in this case?
In the 2018 clinical recommendations, the ESC recognises that “...lowering SBP to <130 mmHg was, in general, associated with no further benefit on major CV events, except perhaps for further reductions in the risk of stroke. A consistent finding was that reducing SBP to <120 mmHg increased the incidence of CV events and death”. Thus, the prevention of major cardiovascular events is less effective when BP reaches ≤120 mmHg. This is especially relevant for elderly patients . Specifically, the advantage of intensive blood pressure management is nullified in the case of more frequent hypotension episodes and syncope conditions . Due to these adverse reactions, the patient may refuse treatment which will lead to more severe consequences. Thus, the optimal BP range recommended for an elderly patient is 130-140 mmHg (systolic BP) and ≤80 mmHg (diastolic BP) . However, in practice, BP control within a tight range is quite difficult.
How to manage then?
We should try to avoid any hypotension episodes, especially symptomatic, among hypertensive elderly patients. To the best of our knowledge, no large-scale randomised studies of transient hypotension intervention in hypertensive patients have been carried out. However, there are still some data you can use in your daily practice.
The presence of orthostatic hypotension in the hypertensive patient is a management challenge since there are two opposite phenomena to deal with. First, and of key importance, is to inform the patient about the symptoms of orthostatic hypotension and the situations in which they occur. To that end, it is recommended for the patient to gradually come to a vertical position after a long time lying down, or after meals, as well as after defecation and urination. The patient should also avoid upright positions for long stretches in high temperatures and high humidity. It should be recommended that the patient sleep with the head of their bed raised approximately 30°. Compression stockings and abdominal binders reduce peripheral pooling in the lower limbs, especially for elderly patients, and can prevent the development of orthostatic hypotension .
It is difficult to assess the effectiveness of different classes of antihypertensive pharmaceutical agents for the prevention of orthostatic hypotension due to non-uniform methodologies adopted in major studies. These studies only included episodes of hypotension that led individuals to seek medical help in their statistical analyses [1,13].
It is seen that orthostatic hypotension has been associated with receiving alpha blockers, diuretics, and central sympatholytics [5,14]. It has been suggested that taking calcium channel blockers can also be related to the development of hypotension. According to the results of follow-up research comparing the effect of lisinopril, chlortalidone and amlodipine, only amlodipine caused hypotension. However, this effect was noted only during the first 12 months of treatment, thereafter no intergroup differences were noted . Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers intake have not been associated with the development of orthostatic hypotension, and several studies have indicated their positive effect in the prevention of orthostatic hypotension episodes [14,15].
Drugs with an elimination half-life of 6 to 12 hours, administered no earlier than 3 hours before going to sleep, are recommended for patients with isolated systolic hypertension. For obvious reasons, hypertensive patients are not advised to take vasopressors to treat orthostatic hypotension.
There is little evidence concerning medication for postprandial hypotension.
Advisable non-drug measures include drinking a glass of water before meals, cutting down on simple carbohydrates, eating frequent meals in small portions and staying seated 60 to 90 minutes after meals. Some studies report the positive role of caffeine in the prevention of postprandial hypotension episodes, so having coffee or tea before meals could have a positive effect .
As noted earlier, the reasons for symptomatic hypotensive episodes in elderly individuals are not known. Whether the same recommendations made for orthostatic and postprandial hypotension management can be applied to these patients remains unclear.
Is it worth refusing aggressive hypertension treatment in elderly patients with transient hypotension that has no apparent cause? Seemingly, yes. However, this category of patients is quite common and constituted approximately one-half of the cohorts for both the Systolic Blood Pressure Intervention Trial (SPRINT) and Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) studies – two clinical trials that proved the relevance of intensive BP control while reporting no cardio- or cerebrovascular complications [1,17].
As mentioned above, symptomatic hypotension is likely to be caused by functional and structural circulation disorders in the brain and the heart. Obviously, active hypotension therapy improves these parameters and can be beneficial for patients with symptomatic hypotensive episodes. A likely cure for such patients may be the drugs that improve ischaemic tolerance. Moderate exercise also has a good effect on the vegetative regulation of blood circulation and therefore can be recommended for patients with symptomatic hypotensive episodes .
Since symptomatic hypotensive episodes can be considered a manifestation of excessive blood pressure variability, it is possible that the treatment methods aimed at reducing the BP variability can prove effective. Here again, one must stress the importance of physical training . Furthermore, thiazide-type diuretics and calcium antagonists are known to be effective in this situation [20,21]. For apparent reasons, patients should be administered lower diuretic doses if possible and prolonged calcium channel blockers.
Conclusions and take-home messages
- When dealing with elderly patients, it is important for the treating physician to not only achieve the target blood pressures, but to avoid transient hypotension.
- Reported varieties of episodic hypotension include not only orthostatic, postprandial, medication-related, and exercise stress hypotension, but also occurrences of hypotension that have no explicit reason and which are experienced by more than half of older hypertonic patients.
- Short-term hypotension accompanied by adverse symptoms, especially if experienced repeatedly, can have an unfavourable prognosis.
- The hypotension events, especially symptomatic, should be identified and brought to light with the help of interviews, as well as HBPM and ABPM.
- Consideration must be given when selecting treatment. The episodes of hypotension are not likely to be counter-indicative for target blood pressures. Patients with transient hypotension can benefit from calcium antagonists and thiazide diuretics in low doses, while patients with orthostatic and postprandial hypotension should follow specific lifestyle recommendations.