Blood pressure (BP)
is the force exerted by the blood against the walls of the blood vessel. It must be adequate to maintain tissue perfusion during activity and rest.
Regulation of BP involves
nervous, cardiovascular, endothelial, renal, and endocrine functions.
Hypertension or high blood pressure
is defined as a persistent systolic blood pressure (SBP) 140 mm Hg, diastolic blood pressure (DBP) 90 mm Hg, or current use of antihypertensive medication.
Prehypertension:
BP 120-139/80-89 mm Hg
Hypertension stage 1:
BP 140-159/90-99 mm Hg
Hypertension stage 2:
systolic BP 160 or diastolic BP 100 mm Hg.
Isolated systolic hypertension (ISH)
average SBP 140 mm Hg coupled with an average DBP <90 mm Hg. ISH is more common in older adults. Control of ISH decreases the incidence of stroke, heart failure, cardiovascular mortality, and total mortality.
Pseudohypertension (false hypertension)
occurs with advanced arteriosclerosis.
Primary (essential or idiopathic) hypertension
elevated BP without an identified cause; accounts for 90% to 95% of all cases of hypertension.
Secondary hypertension
elevated BP with a specific cause; accounts for 5% to 10% of hypertension in adults.
SVR
The hemodynamic hallmark of hypertension that is persistently increased.
This persistent elevation in SVR may come about in various ways
Abnormalities of any of the mechanisms involved in the maintenance of normal BP, including sodium intake, the renin-angiotensin-aldosterone mechanism, and sympathetic nervous system (SNS) stimulation, can result in the development of hypertension.
primary hypertension
Abnormalities of glucose, insulin, and lipoprotein metabolism are common in
Contributing factors to the development of hypertension
include cardiovascular risk factors combined with socioeconomic conditions and gender and ethnic differences.
silent killer
frequently asymptomatic until it becomes severe and target organ disease occurs.
Target organ diseases
occur in the heart (hypertensive heart disease), brain (cerebrovascular disease), peripheral vasculature (peripheral vascular disease), kidney (nephrosclerosis), and eyes (retinal damage).
Damage to retinal vessels provides an indication of concurrent
vessel damage in the heart, brain, and kidney. Manifestations of severe retinal damage include blurring of vision, retinal hemorrhage, and loss of vision.
There is a direct relationship between hypertension and
cardiovascular disease (CVD).
Angiotensin-converting enzyme (ACE) inhibitors
prevent the conversion of angiotensin I to angiotensin II and reduce angiotensin II (A-II)-mediated vasoconstriction and sodium and water retention.
A-II receptor blockers (ARBs)
prevent angiotensin II from binding to its receptors in the walls of the blood vessels.
Most patients who are hypertensive will require
two or more antihypertensive medications to achieve their BP goals.
Resistant hypertension
is the failure to reach goal BP in patients who are adhering to full doses of an appropriate three-drug therapy regimen that includes a diuretic.
Older adults
are sensitive to BP changes and may by resistant to the effects of ACE inhibitors and ARBs.
The goal for treating primary hypertension is
BP <140/90 mm Hg
Diuretics
promote sodium and water excretion, reduce plasma volume, and reduce the vascular response to catecholamines.
Adrenergic-inhibiting agents
act by diminishing the SNS effects that increase BP. Adrenergic inhibitors include drugs that act centrally on the vasomotor center and peripherally to inhibit norepinephrine release or to block the adrenergic receptors on blood vessels.
Direct vasodilators
decrease the BP by relaxing vascular smooth muscle and reducing SVR.
Calcium channel blockers
increase sodium excretion and cause arteriolar vasodilation by preventing the movement of extracellular calcium into cells.
Angiotensin-converting enzyme (ACE) inhibitors
prevent the conversion of angiotensin I to angiotensin II and reduce angiotensin II (A-II)-mediated vasoconstriction and sodium and water retention.
A-II receptor blockers (ARBs)
prevent angiotensin II from binding to its receptors in the walls of the blood vessels.
Hypertensive crisis
indicate either a hypertensive urgency or emergency. This is determined by the degree of target organ damage and how quickly the BP must be lowered.Hypertensive emergencies require hospitalization with intensive care monitoring and the intravenous (IV) ad
Hypertensive urgency
develops over days to weeks; the BP is severely elevated but there is no clinical evidence of target organ damage. Does not require IV medications, follow up within 24 hours