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Overview of Blood Pressure Disorders

Blood PressureClinically, one’s level of blood pressure (BP) is determined by the average of 2 or more separate BP readings at two or more separate times. The criteria for its diagnosis as well as the proper technique for obtaining an accurate BP must be used for the diagnosis to be valid.

Blood pressure is composed of two measurements:

  • Systolic pressure: The pressure in arteries during systole (contraction of the heart muscle).
  • Diastolic pressure: The pressure in arteries between cardiac contractions, representing the resting vascular resistance of the tissues.

Hypertension Definitions

  • Normal blood pressure: Systolic <120 mmHg and diastolic <80 mmHg (<120/<80)
  • Elevated blood pressure: Systolic 120 – 129 mmHg while diastolic is still <80 mmHg (120-129/<80)
  • Hypertension stage 1: Either systolic 130 – 139 mmHg or diastolic 80 – 89 mmHg
  • Hypertension stage 2: Either systolic ≥ 140 mmHg or diastolic ≥ least 90 mmHg

Since there are two numbers involved (systolic/diastolic), the higher (more abnormal) number determines which stage is present.

  • Treated hypertension: A normal BP in those requiring medication to keep it normal.

Because BP can vary from moment to moment and depend on patient position, respiration, or activity, inaccuracies can be corrected by having patients undergo “ambulatory” or home BP monitoring.

Primary vs Secondary Hypertension

Blood pressure slowly rises with age, but blood pressure disorders arise due to smoking, obesity, alcohol consumption, stress, thyroid disease, dyslipidemia (unhealthy elevations of cholesterol and triglyceride), genetics, high sodium diet, stimulants, hormones, kidney disease, diabetes, adrenal tumors, and many other causes. These are referred to as “secondary” hypertension.

The most common type of hypertension, however, is “primary” hypertension, for which a definitive cause is not identified.

Complications of Hypertension

Hypertension is usually a co-morbidity within a spectrum of cardiovascular conditions, such as atherosclerosis and abnormal lipid elevations. These contribute to obstructive plaques in arteries which limit perfusion to the heart and other organs. The most notorious of complications include heart attack (myocardial infarction) and stroke; also ominous, however, are claudication (blockage of blood flow to arteries of the extremities causing pain), paresthesias (abnormal sensations from damage to nerves), and ischemia to organs supplied by compromised arteries, e.g., mesenteric ischemia which threatens the viability of the entire intestinal tract, renal hypertension, or myocardial ischemia from atherosclerosis of the coronary arteries.

Hypertensive Emergency

Typically, due to secondary hypertension, a hypertensive emergency is with a BP ≥ 180/≥ 120 and there is evidence of organ damage occurring. There can be neurologic symptoms, nausea, chest pain from myocardial ischemia, dyspnea due to pulmonary edema, or back pain due to aortic dissection.

How Are Blood Pressure Disorders Diagnosed?

The diagnosis of hypertension relies on an accurate appraisal of blood pressure.

  • Normal blood pressure: Systolic <120 mmHg and diastolic <80 mmHg (<120/<80)
  • Elevated blood pressure: Systolic 120 – 129 mmHg while diastolic is still <80 mmHg (120-129/<80)
  • Hypertension stage 1: Either systolic 130 – 139 mmHg or diastolic 80 – 89 mmHg
  • Hypertension stage 2: Either systolic ≥ 140 mmHg or diastolic ≥ least 90 mmHg

Blood pressure measurement is based on audible changes in the pulse across a brief application of a range of pressures, applied via an inflatable cuff around the arm. The initial inflation creates a pressure high enough to stop arterial flow (a tourniquet effect) and then produces sounds from return of pulses and then to silence again as the pressure is released. Both of these events (return of pulses after the silence and changes in the pulses as turbulence resolves) or, simply, the reappearance of pulses and their disappearance again, are recorded as the two numbers (systolic reading and diastolic reading) of the blood pressure.

There are many errors that can invalidate a blood pressure reading, such as crossing of legs, arm position, animated conversation, improper cuff size, and breathing movements. Also, nervousness can result in “white coat hypertension,” which can be misleading.

Correcting for these inaccuracies uses two out-of-office basic strategies:

  • Home monitoring: In which a patient can perform blood pressure measurements as many times and as frequently as is convenient.
  • Ambulatory monitoring: The standard for out-of-office BP evaluation, in which a recorder works wirelessly with an arm cuff over hours to days to increase the data to improve accuracy of the average blood pressure over time.

Diagnosis also involves testing and appraisal of the co-morbidities associated with hypertension:

  • Blood work: A complete metabolic profile (including serum calcium and creatinine, fasting glucose), complete blood count, thyroid hormone level, and kidney and liver function testing, including liver enzymes and estimation of a glomerular filtration rate, respectively.
  • Electrocardiogram (ECG): An ECG can identify structural and rhythmic abnormalities.
  • Echocardiogram: Ultrasound can evaluate the heart chambers (e.g., ventricular enlargement) and the flow of blood through them, as well as judge the competency of the valves which may play a part in hypertension.
  • Appraisal of lifestyle: To identify high-risk stressors that could benefit from counseling and stress-reduction strategies.

Management of Blood Pressure Disorders

The most conservative approach is usually the first treatment strategy:

  • lifestyle changes
  • Low salt diet
  • Potassium supplementation
  • Quit smoking, if a smoker
  • Weight loss via caloric restriction and nutritional counseling
  • Exercise to address a sedentary lifestyle, especially in sedentary occupations
  • Alcohol restriction (avoid excesses)
  • Psychological counseling to identify stressors and to develop coping skills to handle them
  • CPAP for obstructive sleep apnea, which is associated with hypertension

Pharmacologic Therapy

When conservative measures fail or when a patient is non-compliant with them, pharmacologic therapy is indicated, which can reduce heart failure by 50%, stroke by 30-40%, and myocardial infarction by 20-25%.

Drug therapy is typically begun when the out-of-office mean BP is ≥130 systolic or ≥80 diastolic. These same criteria apply even when there are no out-of-office data, but the ≥130/≥80 criteria are met with office BP readings in patients who have one or more of the following:

  • Age >65
  • Any cardiovascular disease
  • Type 2 diabetes
  • Chronic kidney disease

Monotherapy

Depending on age, race, and/or the presence of diabetes (DM), initial therapy begins with one of 4 medications:

  • Thiazide diuretics
  • Calcium channel blockers
  • ACE (angiotensin-converting enzyme) inhibitors
  • ARBs (angiotensin II receptor blockers)

Combination Therapy

When monotherapy fails to achieve a target BP (the “goal” BP), a combination of an ACE inhibitor or ARB with a calcium channel blocker can be tried. (Alternately, the ACE inhibitor or ARB can also be used with a thiazide diuretic). When this fails, an ACE inhibitor or an ARB in combination with both a calcium channel blocker and the diuretic.

If a patient cannot tolerate the typical combination therapeutic choices, a beta blocker, alpha blocker, or arterial vasodilator can be used.

When results are good and a normal BP remains stable for a few years, the dose and number of antihypertensive agents can be reduced as a trial, as many patients maintain their normal BPs off medications for years, especially if they have lost weight.

How Can I Prevent Blood Pressure Disorders?

Nothing can be done to prevent hypertension due to genetics or age, the usual suspects in primary hypertension, but much can be done to prevent secondary hypertension. It is simply a matter of acting on its causes.

  • Quit smoking: To prevent atherosclerosis and COPD, which impacts cardiac function and BP.
  • Lose weight: To address a metabolic syndrome, which also contributes to Type 2 DM (which–itself–further encourages hypertension).
  • Avoid stimulants: Be wary of allergy medications and avoid illicit drug abuse, especially cocaine and methamphetamines.
  • Do not use appetite-suppressants.
  • For diabetics: Strict glycemic control and maintenance of a target hemoglobin A1c of <7%.
  • Follow the prescribed diagnostic work-up begun: To identify liver, kidney, adrenal, or thyroid disease and comply with the indicted therapy.

For those with documented hypertension, prevention of further progression or decreasing the risk to other organs relies on compliance with both lifestyle changes and taking the prescribed antihypertensive medication(s) as prescribed.

For those with secondary hypertension due to thyroid dysfunction, chronic kidney disease, alcoholism, or diabetes, aggressively managing these will also pay off in a favorable impact on the hypertension.

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This information is provided by Vascular Health Clinics and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.

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