most common cardiovascular disease and most common cause of premature disability and death
high blood pressure (~50 million people in the US have hypertension)
defined as systolic or diastolic blood pressure greater than or equal to 140/90
high blood pressure
- cause unknown-difficult to identify cause
2. 90-95% of hypertensive patients
primary (essential) hypertension
known cause. ex: NSAIDS, caffeine, ephedrine
secondary hypertension
Name some mechanisms that contribute to essential hypertension
- neuronal mechanisms
- peripheral autoregulatory mechanisms
- humoral factors
- vascular endothelial mechanisms
- overstimulation by SNS
2. disturbance in baroreceptor reflex
neuronal mechanisms
kidneys reset equilibrium point for appropriate blood volume to a higher level which leads to increased blood volume
peripheral autoregulatory mechanisms
- increased activation of RAAS system
2. insulin resistance and hyerinsulinemia
humoral factors
- can lead to activation of SNS
- can stimulate hypertrophy of vascular smooth muscle which reduces the internal diameter of arterioles and results in an increase in TPR
- can change sodium and calcium transport across cell membranes of vascular smooth muscle, thereby sensitizing arterioles to vasopressor stimuli
insulin resistance of hyperinsulinemia
- deficiency in local vasodilator substances (bradykinin, nitric oxide)
- increased production or release of vasoconstriction substances (endothelin)
vascular endothelial mechanisms
Risk factors
- increasing age
- excessive dietary salt intake
- black race
- BMI >30 (obesity)
- genetic susceptibility
- insulin resistance and compensatory hyperinsulinemia
- cigarette smoking
- excessive alcohol
- lack of regular aerobic physical activity
- use of oral contraceptives
- low dietary potassium
many vascular changes occur with aging-vessels become stiffer and less compliant
increasing age
- can increase fluid retention and blood volume
- can stimulate vascular hypertrophy and stiffness of vasculature
- can stimulate ventricular remodeling and increase left ventricular mass-independent of changes in BP (ventricle remodeling ultimately causes impaired function due to apoptosis or myocardial cells and fibrosis of the myocardial muscle)
excessive dietary salt intake
in part due to extreme sensitivity to salt (do not excrete salt as readily as other races)
black race
obesity is associated with:
- insulin resistance
- decreased fluid volume
- increased stimulation of SNS
- increased stimulation of RAAS
- inflammation
nicotine causes discharge of catecholamines
cigarette smoking
may involve increased plasma catecholamines
excessive alcohol
can stimulate RAAS
use of oral contraceptives
potassium consumption increases excretion of _____
sodium
HTN accelerates ___________
atherosclerosis
HTN causes left ventricular ___________ and dysfunction
hypertrophy
what is the main causes of death in hypertensive patients
- strokes
- cardiovascular accidents (atherosclerosis with resulting MI, HF)
- renal failure (due to arteriosclerosis in renal arteries)
pharmacological therapy (have an idea of how these drugs affect MAP=CO X TPR
- ACE inhibitors
- ARBs
- Renin inhibitors
- Aldosterone antagonists
- Beta Blockers
- CCBs
- Diuretics
- Arteriole vasodilators
