Defining Hypertension: Challenges and Implications for Treatment

Hypertension is a significant public health issue, and the World Health Organization (WHO) has defined it as systolic blood pressure equal to or greater than 160 mmHg, and/or diastolic blood pressure equal to or greater than 95 mmHg. Those with systolic pressure under 160 mmHg but diastolic pressure between 90-94 mmHg, or with systolic pressure between 141-159 mmHg and diastolic pressure under 90 mmHg, are classified as having borderline hypertension. People with blood pressure below these levels are considered 'normotensive.' However, these thresholds are somewhat arbitrary because blood pressure is a continuous variable, meaning there is no clear cut-off between normal and abnormal levels.

Most cases of hypertension fall under the category of 'essential' hypertension, where no specific underlying cause can be identified. This type of hypertension, unlike diseases with distinct causes, reflects a deviation in degree rather than kind—essentially, it is a quantitative problem. This concept can be challenging for doctors, who are trained in binary thinking, where conditions are often classified as present or absent based on clear-cut criteria. Essential hypertension defies this binary categorization, as it presents a spectrum of severity.

The definitions of hypertension are also pragmatic in nature. They are primarily designed to identify individuals who may benefit from specific treatments, whether pharmacologic or non-pharmacologic. For instance, the cut-off points for hypertension are often based on evidence from randomized controlled trials that show treatment benefits for people with blood pressure above certain levels. These benefits must outweigh the potential risks of treatment. However, such definitions can inadvertently exclude a large number of individuals who are still at increased risk due to their elevated blood pressure levels but fall below the threshold for therapeutic intervention. This highlights the need for a more nuanced approach to managing hypertension, one that takes into account the broader spectrum of risk rather than relying solely on rigid cut-offs for treatment eligibility.
Defining Hypertension: Challenges and Implications for Treatment

Understanding White Coat Hypertension

White coat syndrome, or white coat hypertension, refers to the phenomenon where an individual's blood pressure is elevated in a medical setting compared to readings taken at home. The term originates from the traditional attire worn by healthcare professionals during examinations. This condition can cause misleadingly high blood pressure readings, potentially leading to unnecessary treatment or incorrect diagnoses. However, it's essential to note that in some instances, elevated readings in medical environments could indicate underlying hypertension issues.

Research suggests that individuals experiencing white coat hypertension may face an increased risk of cardiovascular complications and organ damage compared to those with stable blood pressure levels. It's crucial to identify contributing factors to hypertension, including age, obesity, tobacco use, sedentary lifestyles, stress, excessive alcohol consumption, and poor dietary habits. Additionally, specific populations, such as African-American men and those with chronic conditions like diabetes and kidney disease, are particularly vulnerable to hypertension and its variant, masked hypertension.

Recent studies have highlighted the importance of accurately diagnosing and managing white coat syndrome to prevent unnecessary medical interventions and complications. Advances in remote monitoring technology have empowered patients to track their blood pressure at home, providing healthcare providers with more comprehensive data for diagnosis and treatment decisions. Understanding the complexities of white coat hypertension enables healthcare professionals to tailor interventions effectively and mitigate the long-term health risks associated with this condition.
Understanding White Coat Hypertension

Elevated blood pressure

Blood pressure is the measurement of the pressure or force of blood pushing against blood vessel walls. Elevated blood pressure is blood pressure that is slightly higher than what is considered ideal.

Anything that increases pressure on the artery walls can lead to elevated blood pressure. A buildup of fats, cholesterol, and other substances in and on the artery walls (atherosclerosis) can cause elevated blood pressure.

Elevated blood pressure is a systolic pressure ranging from 120 to 129 mm Hg and a diastolic pressure below (not above) 80 mm Hg. People with elevated blood pressure are likely to develop high blood pressure unless steps are taken to control the condition.

Either an elevated systolic or an elevated diastolic blood pressure reading may be used to make a diagnosis of high blood pressure.

Elevated blood pressure is a serious medical condition that significantly increases the risks of heart, brain, kidney and other diseases. Long-term elevated blood pressure can lead to changes in memory, language, thinking or judgment (cognitive decline).
Elevated blood pressure

Definition of stroke

Strokes are brain attacks. They occur when the blood supply to the brain becomes blocked. A stroke is a medical emergency that needs immediate medical attention. Stroke can be defined as abrupt onset of a focal neurological deficit lasting more than 24 hours. It is also called cerebrovascular accident (CVA) or apoplexy. An acute stroke refers to the first 24-hour-period of a stroke.

The majority of strokes occur when blood vessels to the brain become narrowed or clogged with fatty deposits called plaque. This cuts off blood flow to brain cells.

Stroke is classified on the basis of its aetiology as either ischaemic (87%)or haemorrhagic (13%).
*Ischaemic stroke is produced by occlusion of a cerebral artery [thrombotic or atherosclerotic (50%), embolic (25%) and microartery occlusion, “lacunar stroke”, (25%)].
*Haemorrhagic stroke is caused mainly by spontaneous rupture of blood vessels or aneurysms or secondary to trauma.

Stroke remains the second leading cause of death at the global level and in the European region. Of the 56 million deaths that occur every year worldwide, 10.8% are due to stroke. Eighty-five per cent of these stroke deaths among all ages occur in developing countries.

The word “stroke” was likely first introduced into medicine in 1689 by William Cole in A Physico-Medical Essay Concerning the Late Frequencies of Apoplexies. Before Cole, the common term used to describe very acute nontraumatic brain injuries was “apoplexy.” Apoplexy was used by Hippocrates circa 400 BC.

Definition of stroke

Resistant hypertension: definition and prevalence

Resistant hypertension is generally defined as uncontrolled clinic blood pressure (>140/90 mm Hg) after treatment with three or more antihypertensives. Ideally, one of the 3 agents should be a diuretic and all agents should be prescribed at optimal dose amounts.

It is estimated that 20–30% of patients treated for hypertension have uncontrolled blood pressure, however the true prevalence of resistant hypertension is estimated at 8–18%.

In the NHANES study, target blood pressure (BP) values, were achieved in only 53% of the patients treated with antihypertensive drugs. An even lower percentage of BP target levels, i.e. < 130/80 mm Hg, was observed in patients with diabetes and chronic kidney disease.

A large study based on the Spanish Ambulatory Pressure Registry covered about 68,000 patients treated for hypertension, 12% of whom were diagnosed with resistant hypertension (RH). Ambulatory blood pressure measurement (ABPM) confirmed true resistance to treatment in 62.5% of the patients, and in the remaining 37.5%, the ineffectiveness of the therapy was due to the white coat effect.

Lifestyle changes may be recommended in order to reduce overall hypertension. Patients with resistant hypertension should adhere to the same nutritional and behavioral recommendations valid for the general hypertensive population.

Therefore, weight loss should be encouraged in overweight and obese patients; smoking cessation should be promoted, together with a moderation of alcohol consumption, a reduction of sodium intake and an increase in physical activity.
Resistant hypertension: definition and prevalence

What is arteriosclerosis?

Arteriosclerosis is the vascular disease that is the leading cause of mortality in industrialized countries. Arteriosclerosis is a general term use to describe several conditions in which the arteries become narrow and blocked, also known as hardening of the arteries. The condition is a leading cause of stroke and is associated with heart disease, hypertension, diabetes and other disorders.

Arteriosclerosis produces fatty material, called plaque that accumulates and lines the artery walls. The arteries become smaller in diameters, then clogged. This results in decreases blood circulation or cessation of the blood flow.

The deposits can partially or completely obstruct blood flow to the heart the brain and other vital organs. Arteries in the arms, legs, hands and feet can also be affected.

Coronary artery disease is one type of arteriosclerosis that affects only the inner linings of arteries; it is responsible for most heart disease. Obesity is strongly associated with the metabolic syndrome, which promotes arteriosclerosis and coronary artery disease.

Currently, there are 3 lesions within the broader category of arteriosclerosis:
*Atherosclerosis
*Monckeberg’s arteriosclerosis
* Arteriolosclerosis: associated with hypertension
What is arteriosclerosis?

Nocturnal hypertension

Nocturnal is the behavior characterized by being active during the night. Nocturnal blood pressure is the blood pressure measured during bedtime to arising or between 1 am and 6 am by ABPM or home blood pressure.

Nocturnal hypertension is diagnosed by the average of nocturnal BPs
>125/75 mmHg. The value was suggested by American Heart Association.

This threshold was lowered by the European Society of Hypertension updated practice guidelines that considered a nighttime blood pressure of greater than 120/70 mmHg to be abnormal.

Nocturnal hypertension is also an independent risk factor for cardiovascular morbidity.
Nocturnal hypertension

Definition of Hypotension

Hypotension is abnormally low blood pressure readings, which may be found among very ill or elderly individuals or among those with severe hyperthyroidism, pituitary failure and Addison’s disease. Clinically, when the systolic blood pressure is less than 9 mm Hg, it is considered hypotension.

There are two types of hypotension: orthostatic hypotension and Shy-Grager syndrome. Idiopathic orthostatic hypotension also known as postural hypotension is a syndrome of symptoms due to degeneration of postganglionic sympathetic neurons confined to the autonomic system. It is sudden drop in blood pressure (about 20 mm Hg in the systolic pressure) that occurs when person changes from a lying down to a sitting-up position or from sitting-up to a standing position.

Shy-Grager syndrome is due to multiple systems degeneration with more widespread neurologic damage, including autonomic dysfunction with cerebrellar atraxia, parkinsonism, corticospinal, and corticobulbar tract dysfunction, and amyotrophy.

Hypotension can be dangerous because it can impair people so much they experience severe falls and fractures.
Definition of Hypotension

Causes of refractory hypertension

Hypertension is considered refractory if the blood pressure (BP) cannot be reduced below 140/90 mmHg in patients who are compliant with an appropriate triple-drug regimen that includes a diuretic, with all the component prescribed in near maximal or tolerated doses.

The most common causes are poor compliance, alcohol access and obesity. In addition, blood pressure becomes increasingly difficult to control in the presence of deteriorating renal function.

Additional etiologies include renal artery, stenosis, sleep apnea and the other secondary causes of hypertension. Other causes: nonadherence to therapy, white coat hypertension, pseudo-hypertension, antihypertensive drug dose too low, and sedentary lifestyle.

Approximately 10% of patients with refractory hypertension will have a secondary cause, medication use and compliance, nonpharmacologic management strategies and excessive alcohols use are frequently overlooked causes.
Causes of refractory hypertension

The nature of essential hypertension

Essential or primary hypertension was considered to have no obvious cause. It comprises 90%-95% of all hypertension, with secondary hypertension (renal, endocrine and vascular) comprising the remainder.

The concept that essential hypertension has its root in childhood can be inferred from blood pressure tracking data, which demonstrate that children with elevated blood pressures will continue to have elevated blood pressures as adults.

In developed countries, the risk of becoming hypertensive during a lifetime, defined for adults as pressures greater than 140/90 mm Hg, exceeds 90%.

Essential hypertension is commonly associated with other cardiovascular risk factors such as ageing, being overweight, insulin resistance, diabetes and hyperlipidaemia.

There is a strong genetic component in essential hypertension. Essential hypertension in human is also associated with increased sodium transport in the renal proximal tubule and medullary thick ascending limb, although increased distal tubular transport has also been reported.
The nature of essential hypertension

Stage I type of Hypertension

In Stage I type of Hypertension, there are no other major health problems. Stage 1 hypertension is defined as either a systolic blood pressure of 140 to 159 mm Hg or a diastolic blood pressure of 90 to 99 mm Hg.

Patients with stage 1 hypertension should begin diet and lifestyle changes and should receive one antihypertensive medication, usually a thiazide diuretic.

Consideration is made to give angiotensin converting enzyme inhibitor, angiotensin receptor blocker, beta blocker, calcium channel blocker or a combination of these of the individual is still not meeting the goal blood pressure.

All person classified with either stage 1 hypertension or stage 2 hypertension should be treated and have a therapeutic goal of achieving a BP of less than 140/90 mm Hg.
Stage I type of Hypertension

Renovascular hypertension

In most Westernized countries, and especially among older individuals, renovascular hypertension is the most remediable cause of elevated blood pressure.

Renovascular hypertension is a reversible cause of hypertension secondary to a decrease in renal perfusion pressure which activates the renin-angiotensin system and leads to the release of rennin and the production of angiotensin II.  It is a progressive disorder that can result in serious complications without adequate treatment.

Angiotensin II increases sodium reabsorption and induces postglomeruler and systemic arterial vasoconstriction, causing renovascular hypertension. The prevalence of renovascular hypertension was estimated at about 5% of all hypertensive individuals but it is varied form less than 1% to more than 50% depending on the degree of screening in the study population.

With prevalence of about 5%, renovascular disease represents the most frequent cause of secondary hypertension.

Unlike the diagnosis of most other cardiovascular and nephorologic conditions, renovascular hypertension can be diagnosed only retrospectively, by means of a physiologic blood pressure (BP) response to an intervention.
Renovascular hypertension

Idiopathic pulmonary arterial hypertension

Primary arterial hypertension is and has often been classified into two separate categories: primary pulmonary (arterial) hypertension, and secondary pulmonary arterial hypertension.

The term ‘primary’ pulmonary hypertension was replaced by ‘idiopathic’ pulmonary hypertension and when there was a genetic basis, ‘familial’ pulmonary hypertension.

Primary hypertension that occurred along with other conditions was referred to as ‘associated’ pulmonary hypertension.

Idiopathic pulmonary arterial hypertension is highly morbid disease characterized by progressive obliteration of precapillary arterioles.

The disease manifested by progressive pulmonary vascular remodeling, compromised pulmonary blood flow and right heart failure.

Idiopathic pulmonary arterial hypertension is rare, occurring in one to two cases per one million people per year, with an overall prevalence estimated at 1300 per one million.

According to World Health Organization (WHO) estimated, there are 5000 patients with Idiopathic pulmonary arterial hypertension in the United States and Europe. However, the prevalence may be increased because of heightened awareness and early recognition in minimally symptomatic patients.
Idiopathic pulmonary arterial hypertension

Resistant hypertension

Hypertension has generally been defined as resistant when it remains uncontrolled despite a ‘good’ regimen of 3-antihypertensive drugs at full dosage.

Resistant hypertension is associated with multiple risk factors and organ damage. The most common reason for resistant hypertension is systolic hypertension in older individuals, in whom a favorable outcome has been linked to the degree of BP lowering, rather than to the drug type employed.

Poor adherence failure to modify lifestyle, inadequate treatment, white-coat hypertension, and secondary hypertension are all common aetiologies.

In patient with resistant hypertension, subclinical organ damage itself may be responsible for high blood pressure values, but it is also the result of detrimental effects of hypertension on large arteries as well as on the microvascular network.

Resistant hypertension is relatively common in hypertension clinics because of selection by referral, and it is seen in 13-20% of such patients.
Resistant hypertension

What do you know about pulmonary hypertension

Pulmonary (PULL-mun-ary) arterial hypertension (PAH) is continuous high blood pressure in the pulmonary artery. The average blood pressure in a normal pulmonary artery is about 14 mmHg when the person is resting. In PAH, the average is usually greater than 25 mmHg.
PAH is a serious condition for which there are treatments but no cure. Treatment benefits many patients.

The pulmonary arteries are the blood vessels that carry oxygen-poor blood from the right ventricle (VEN-trih-kul) in the heart to the small arteries in the lungs. In PAH, three types of changes may occur in the pulmonary arteries:

*The muscles within the walls of the arteries may tighten up. This makes the inside of the arteries narrower.

*The walls of the pulmonary arteries may thicken as the amount of muscle increases in some arteries. Scar tissue may form in the walls of arteries. As the walls thicken and scar, the arteries become increasingly narrow.

*Tiny blood clots may form within the smaller arteries, causing blockages.

There is less room for the blood to flow through these narrower arteries. The arteries may also stiffen. Over time, some of the arteries may become completely blocked.

The narrowing of the pulmonary arteries causes the right side of heart to work harder to pump blood through the lungs. Over time, the heart muscle weakens and loses its ability to pump enough blood for the body's needs. This is called right heart failure. Heart failure is the most common cause of death in people with PAH.

There are two types of PAH:
*Primary pulmonary arterial hypertension (PPAH) is inherited or occurs for no known reason.
*Secondary pulmonary arterial hypertension (SPAH) either is caused by or occurs because of another condition. The conditions include chronic heart or lung disease, blood clots in the lungs, or a disease like scleroderma (skler-o-DER-ma).

About 300 new cases of PPAH are diagnosed in the United States each year. SPAH is much more common.

Doctors have learned a lot about PAH in recent years. More treatments are now available. Researchers are also studying several promising new treatments that may prolong lives as well as improve the quality of life for people living with PAH.
What do you know about pulmonary hypertension

What is refractory hypertension?

Secondary hypertension can be insidious in its presentation and in many cases presents as refractory hypertension.

Refractory hypertension was defined as BP that remained uncontrolled after more or 3 visits to a hypertension clinic within a minimum 6-month follow-up period. Refractory hypertension represents the extreme phenotype of hypertension treatment failure and is also defined as the persistence of blood pressure more than 140/90 mmHg while being treated with a rational triple-drug therapy, optimally including a diuretic.

Refractory hypertension falls into two broad categories:
*Apparent resistance
*True resistance

Refractory hypertension is present in approximately 10% in a primary care setting and in more than 30% of patients seen in subspecialty clinics.

Approximately 10% of patients with refractory hypertension will have a secondary cause. Medication use and compliance, non-pharmacologic management strategies and excessive alcohol issue are frequently overlooked causes.
What is refractory hypertension?

Symptoms of malignant hypertension

Malignant hypertension is a rare syndrome consisting of rapid and severe elevation of blood pressure, with then systolic component above 200 mmHg or the diastolic blood pressure greater than 140 mmHg.

Sign and symptoms of malignant hypertension include neurological changes such as anxiety, confusion, lethargy, numbness, tingling or weakness in the extremism and seizures.

The most common presentations include headaches and visual disturbances, chest pain, and dyspnea.

Other possible symptoms include nausea, vomiting and decreased urine production. Cardiac symptoms such as angina, myocardial infarction and pulmonary oedema my occasionally be the main presenting symptoms.

Malignant hypertension causes target organ damage, particularly to the kidney. The patient is likely in renal failure, indicated by the elevation in blood urea nitrogen and creatinine, the lack of urine production and the metabolite acidosis.

Persistent elevated malignant hypertension can lead to rapidly fatal course, with heart failure, myocardial infarction stroke or renal failure.
Symptoms of malignant hypertension

Causes of secondary hypertension

Hypertension can be primary or secondary to a defined process. Secondary hypertension meaning the hypertension is secondary to a specific cause.

Secondary causes of hypertension are uncommon, and account for less than 5% of all cases of high blood pressure in and unselected hypertension population.

The rate of secondary forms of hypertension ranges between 4 and 8% in different patient populations (primary care, secondary care clinics, or specialized cardiovascular centers).

Secondary hypertension is usually associated with a specific organ and /or vascular abnormalities, a metabolic abnormality, or endocrine disorder.

The majority of secondary hypertension cases are due to chronic renal disease, and therapy often in includes antihypertensive medications.

Secondary hypertension must always be identified because treatment will be based on the specific underlying disorder. Its onset is often sudden, it may be more severe, a family history is frequently absent and it may occur in patients of all ages.

If left undiagnosed, secondary hypertension may lead to progressive target organ damage, as well as cardiovascular and renal complications.

Treatment usually differs from that of ordinary essential hypertension and with the right treatment, the amount of medication often can be reduced.
Secondary hypertension

Resistant hypertension definition

Resistant hypertension is best defined as a blood pressure that remains above goal despite the concurrent use of three antihypertensive agents from different classes, prescribed at optimal dosses, one of which is ideally a diuretic.

The definition also includes patients with normal or elevated blood pressure in the setting of four or more antihypertensive agents.

Central obesity and older age are consistent risk factors for resistant hypertension and as the population ages and gains weight it can be expected that its prevalence will rise further.

Other important risk factors include, chronic kidney disease, diabetes, obstructive sleep apnea, consumption of a high-salt diet, African-American race, and female gender.

Poor adherence, failure to modify lifestyle, inadequate treatment, white coat hypertension and secondary hypertension are all common aetiologies.

Patients with resistant hypertension require careful assessment and vigorous treatment, given their greater degree of target organ damage and adverse long-term cardiovascular risk.
Resistant hypertension definition

What is white-coat hypertension?

White coat hypertension also referred to as isolated office hypertension or isolated clinic hypertension is the most commonly used term to describe patents who display elevated blood pressure as measured by a physician but have otherwise normal daytime mean pressure.

White-coat hypertension is quite common, occurring in about 20 percent of hypertensive patients.

The simplest explanation for the phenomenon of white-coat hypertension is that it occurs because people get anxious when they see their doctor, and this makes the blood pressure go up.

Patients with white-coat hypertension show diversity in metabolic, neuroendocrine and cardiac findings and display greater blood pressure variability compared to those with sustained blood pressure elevations.

In general, white coat hypertension is associated with intermediate risk compared to sustained hypertension.

White coat hypertension appears to be at least as common in children as it is in adults. In adults, white coat hypertension is not felt to be associated with significant cardiovascular morbidity or mortality.
What is white-coat hypertension?