Definition, diagnosis, importance and types of Hypertension
Arterial hypertension (HT) is defined by a systolic blood pressure (SBP) ≧ 140 mmHg or diastolic BP (DBP) ≧ 90 mmHg measured in consultation. This definition is based on evidence from multiple randomized controlled studies indicating that treatment of patients with these blood pressure (BP) values is beneficial. The same classification is used for both young, middle-aged adults and the elderly, whereas other criteria based on percentiles are adopted for children and adolescents, since no data are available from intervention studies in these age groups.
Types of hypertension
There are three fundamental types of arterial hypertension (AHT):
- Secondary HT. It is diagnosed mainly in young people (under 40 years of age) and may be due to various causes (renal artery stenosis, hyperaldosteronism due to excessive endogenous production of aldosterone, pheochromocytoma or catecholamine-producing tumor).
- Pregnancy hypertension or preeclamsia. This can appear in women who were not previously hypertensive and who begin to present high BP levels during pregnancy, a serious situation which, if not adequately treated, can evolve into eclampsia affecting the woman and the fetus.
- Essential or primary hypertension. This is undoubtedly the most common type of HT and usually develops after the age of 40-50 years (although it can also occur in young people). Among other causes, it is due to an imbalance in the renin-angiotensin-aldosterone axis; a neurohormonal system in the human body that regulates BP and the levels of some electrolytes such as sodium.
Primary hypertension (HT) is one of the most prevalent chronic noncommunicable diseases in the adult population in developed countries and one of the most important CVRF (cardiovascular risk factors). Its control is key to significantly reducing morbidity and mortality due to coronary heart disease (myocardial infarction), cerebrovascular disease (ischemic or hemorrhagic stroke), peripheral arterial vascular disease, chronic renal failure and others. It affects, in general, almost 40% of adults.
Arterial hypertension is considered by the World Health Organization as the leading cause of death worldwide, and approximately 9.4 million deaths in the world are related to hypertension. It is a serious health problem that causes serious damage to the body, mainly to the heart, kidneys and retina. Because it hardly shows any symptoms and because of the damage it causes in almost all the organs and systems of the organism, it has been called the “enemy or silent killer”.
It is currently the risk factor that contributes most to cardiovascular mortality and it is estimated that 54% of strokes and 47% of acute coronary syndromes are attributable to HT.
ABPM or Holter blood pressure monitoring: what is its usefulness and what are its advantages?
Ambulatory Blood Pressure Monitoring (ABPM) or Holter monitoring of blood pressure is currently the most effective and accurate technique for the diagnosis and control of blood pressure (BP). It consists of taking multiple measurements of blood pressure, outside the office, over a period of 24-48 hours, using a device that records these measurements and records them for later analysis while the individual carries out his or her usual physical activity and work in his or her environment.
The measurement of BP (blood pressure) in consultation (CAP) continues to be a common practice, but it is subject to multiple technical biases, although it is performed according to international standards (NICE, 2011; Hackam DG, 2013; Mancía G, 2014). In addition, it provides a limited number of BP measurements, all of which are taken during the patient’s period of activity, not allowing BP during the rest period (sleep) to be recorded and, on occasions, at times when the drugs are having their least peak pharmacological effect (off-peak period).
In contrast, ABPM has been shown to be a better predictor of cardiovascular morbidity and mortality, provides a greater number of BP readings in the patient’s usual environment, allows the identification of patients with white coat hypertension (HBP) and with white coat phenomenon (individuals with elevated BP levels in the consultation room due to the stress of such measurement by doctors or nurses), demonstrates the presence of nocturnal hypertension, and allows observation of BP variability and the effectiveness of treatments over 24 hours. It also detects the so-called “masked hypertension” (a situation in which patients present normal BP levels at the doctor’s or nurse’s office but actually have elevated BP levels for most of the day). Likewise, it has proven to be the most cost-effective technique for the diagnosis and adequate control of HTN, used both in primary care and at a specialized level (internal medicine, vascular risk units).
On the other hand, HT in pregnancy in its different categories, gestational hypertension, arterial hypertension pre-existing during pregnancy (“chronic” hypertension) and preeclampsia, carry a risk for the evolution and prognosis of both the mother and the fetus in its development, prognosis and mortality, and that is why in these conditions greater precision is required for the early detection of arterial hypertension. On the other hand, blood pressure measurements by ABPM are subject to a lower possibility of error, since with this technique a greater number of measurements are obtained in 24 hours. They are not, on the other hand, subject to errors related to the way of measurement and staff training, etc.
The latest guideline of recommendations for the diagnosis and treatment of HT published in 2018 by the European Society of Arterial Hypertension, points to ABPM, in addition to home self-measurement of BP, as the priority techniques to confirm the diagnosis of HT in doubtful cases and to rule out white coat HT and masked HT.
Therefore, we can conclude that for both the diagnosis and adequate treatment of any type of HT, it is essential to perform at least one examination by Ambulatory Blood Pressure Monitoring (ABPM).