Hypertension Flashcards
what is blood pressure
*measure of adequacy of circulation
*balance between: blood volume ejected by LV & peripheral resistance to blood flow
*adequate BP is vital to perfusion of body tissues
complications of elevated BP
*intracranial hemorrhage
*stroke
*vascular disease
*kidney damage
*hypertensive heart disease
*retinopathy
complications of low BP
*shock
*kidney failure
*anoxic encephalopathy
*lactic acidosis
BP measurement technique: in-office
*2 readings, 5 minutes apart, sitting in chair
*confirm elevated readings in the contralateral arm
BP measurement technique: ambulatory BP monitoring
*indicated for evaluation of “white-coat” HTN
*absence of 10-20% BP decrease during sleep may indicate increased CVD risk
BP measurement technique: self-measurement
*provides information on response to therapy
*may help improve adherence to therapy and evaluate “white coat” HTN
changes in systolic & diastolic BP with age
*systolic BP continues to rise throughout life
*diastolic BP starts to decrease around age 50
*this phenomenon is due to stiffening of blood vessels
cardiovascular disease risk based on BP
*each increment of 20/10 mmHg doubles the risk of CVD across the entire BP range, starting from 115/75 mmHg
*the BP relationship to risk of CVD is continuous, consistent, and independent of other risk factors
ACC/AHA blood pressure classifications
*normal: SBP < 120 mmHg AND DPB < 80
*elevated: SBP 120-129 OR DBP <80
*stage 1 HTN: SBP 130-139 OR DBP 80-89
*stage 2 HTN: SBP 140+ OR DBP 90+
note: whichever value is the higher stage is what HTN you have
epidemiology of HTN
*CVA & SVD are the most common causes of death and disability in developed countries
*HTN is a key modifiable risk factor
*HTN affects nearly 50% of adult population in the world
*primary HTN accounts for 90% of cases
causes of primary HTN
*multifactorial: obesity, insulin resistnace, age, sodium retention, sympathetic activation, etc
target organ damage resulting from long-standing HTN
1) heart:
-left ventricular hypertrophy
-angina or myocardial infarction
-heart failure
2) brain: stroke or TIA
3) chronic kidney disease
4) peripheral arterial disease
5) retinopathy
6) aortic aneurysms and dissections
pathophysiology of LV hypertrophy as a result of long-standing HTN
*according to law of Laplace (wall stress law), INCREASING THE THICKNESS OF THE LV WALL actually DECREASES the wall stress
*hence, an increase in wall thickness in response to increased pressure maintains/decreases wall stress
heart failure and HTN
*people in heart failure are extremely sensitive to small changes in blood pressure (compared to people without heart failure)
*therefore, we need to maintain their BP even lower than normal because it does not take much afterload to compromise their stroke volume
HTN complication: higher wall thickness:lumen ration in the arteries
*law of Laplace applies to arteries too (increasing the wall thickness helps to decrease the wall stress)
*therefore, arteries and arterioles become hyperplastic/hypertrophied, which can lead to more complications down the line
medication timeline for preparing a pheochromocytoma patient for surgery
- epinephrine from the tumor → BP to increase
- give phenoxybenzamine first (an irreversible alpha blocker) → BP goes LOWER THAN ORIGINAL BASELINE b/c the catecholamines are going to beta 2, causing vasodilation
- give non-selective beta blocker
