Partial 3 - Arterial hypertension Flashcards
Normal systolic and diastolic blood pressure
Systolic is <120mm Hg
Diastolic is <80mm Hg
Pulse pressure
The pulse pressure is the difference between systolic and diastolic pressures and is normally 40, and it may be a better marker of increased CV risks than either of SBP and DBP alone in older persons
The mean arterial pressure can be calculated by
Adding 1/3 of systolic pressure to 2/3 of diastolic pressure.
Blood pressure is
Cardiac output multiplied by total peripheral resistance
Cardiac output is
Stroke volume (amount of blood ejected from the heart with each beat) multiplied with heart rate.
Prehypertensive patients systolic and diastolic pressure
Systolic pressure of 120-139 mm Hg
Diastolic of 85-89 mm Hg
Hypertensive stage 1 patients systolic and diastolic pressure
Systolic pressure of 140-159 mm Hg
Diastolic pressure of 90-99 mmHg
Hypertensive stage 2 patients systolic and diastolic pressure
Systolic pressure of 160 mm Hg or more
Diastolic pressure of 100 mm Hg or more
Hypertension can be decreased by
Weight reduction Adopting eating plan Reduction of dietary sodium Physical activity Moderation of alcohol consumption.
Which type of hypertension accounts for 90-95% of all cases of hypertension?
Primary (Essential) hypertension
Constitutional factors that cause primary hypertension
Family history of hypertension (multiple genes are involved, while single genes such as Liddle’s syndrome are uncommon)
Race (blacks are mostly affected)
Age-related hypertension
Lifestyle factors that cause primary hypertension
High salt diet
Excessive calorie intake and obesity
Excess alcohol consumption.
Cardiac output and TPR in young hypertensive patients
Usually hypertension in young patients there is high resting cardiac output (increased systole) and normal TPR (normal diastole)
Cardiac output and TPR in patients that have had hypertension for 12-20 years
In people that have had hypertension in 10-20 years, there is decreased cardiac output, and increased TPR probably due to cardiac and vascular remodelling.
Renin levels in 70% of patients with hypertension
Elevated or normal
Changes in TPR may be caused by
Altered blood vessel structure
Arterial stiffness
Cell membrane alterations
TPR is controlled by two cell types
Vascular endothelial cell
Vascular smooth muscle cell
What alteres the blood vessel structure?
Renin angiotensin II Endothelin Transforming Growth Factor B1 Insulin like growth factor Excess response to hemodynamic shear Decreased nitric oxide
Pathogenesis Miscellany
Obesity leads to hypertension, and for every ten pounds of weight gain, systolic BP increases by 4.5 mm Hg
Low intake of calcium, potassium and magnesium all is associated with increased BP, and lead also causes hypertension
Use of tobacco increases the BP for 30 minutes after acute ingestion
Caffeine increases BP but one develops tolerance
Even moderate quantities of alcohol may lead to hypertension.
Obesity mechanism in hypertension
Increases cardiac output Increases intravascular volume Increases RAS (reticular activating system and SNS activity) Decreases Nitric oxide Causes hyperinsulinemia
Pathogenesis Angiotensin II - Heart
Myocardial hypertrophy
Intestinal fibrosis
Pathogenesis Angiotensin II - Coronary arteries
Endothelial dysfunction with decreased release of nitric oxide
Coronary constriction via release of norepinephrine
Formation of oxygen-derived free radicals via NADH (nicotinamide adenine dinucleotide) oxidase
Promotion of inflammatory response and plaque instability
Promotion of low-density lipoprotein cholesterol uptake
Pathogenesis Angiotensin II - Kidneys
Increased intraglomerular pressure Increased protein leak Glomerular growth and fibrosis Increased sodium reabsorption Decreased renal blood flow
Pathogenesis Angiotensin II - Adrenal glands
Increased formation of aldosterone
Pathogenesis Angiotensin II - Coagulation system
Increased fibrinogen
Increased PAI-1 (plasminogen activator inhibitor-1) relative to tissue plasminogen factor
Secondary hypertension causes
Renovascular diseases Renal parenchymal disease Autosomal dominant polycystic kidney disease Coarctation of the aorta Sleep apnea Pheochromocytoma Primary aldosteronism (Conn's syndrome) Cushing syndrome Hyperparathyroidism Hypo/hyperthyroidism Exogenous causes (drugs like cocaine and amphetamines).
Postural hypertension
It is decrease in standing systolic blood pressure by more than 10 mm Hg, which is usually associated with dizziness/ fainting, and is more frequent in older SBP patients with diabetes, taking diuretics, venodilators, and some psychotropic drugs. BP in these individuals should be monitored in the upright position.
Hypertension in women
Oral contraceptives may increase BP, and BP should be checked regularly. In contrast, HRT does not raise BP
Increased BP may lead to - Heart
(1) Increased BP may lead to systolic dysfunction, which leads to decreased ejection fraction, and increased end diastolic volume and left ventricular dilation and thus may result in low cardiac output syndrome
(2) Increased BP may lead to left ventricular hypertrophy which may result in ventricular arrhythmias.
(3) Increased BP may lead to diastolic dysfunction, which leads to normal or increased ejection fraction, normal or decreased end diastolic volume, left ventricular size is normal, which may lead to increased left ventricular filling pressure, and thus results in pulmonary venous congestion and dyspnea
Consequences of hypertension - Heart
Chronic Heart Failure (CHF) LV dysfunction Myocardial Infarction (MI) Sudden cardiac death Ischemic Heart Disease (IHD)
Consequences of hypertension - CNS
Stroke
Retina damage
Consequences of hypertension - Kidneys
Renal failure
Proteinuria
Does hypertension also lead to peripheral vascular diseases?
Yes
Liddle’s syndrome (pseudoaldosteronism)
Etiology
Autosomal dominat disorder characterized by early and frequently severe hypertension associated with low plasma renin activity, metabolic alkalosis due to hypokalemia and normal to low levels of aldosterone
Etiology:
Dysregulation of an epithelial sodium channel. Increased activity of this channel leads to increased sodium reabsorption, increased extracellular volume and hypertension
What treatment in patients with end stage renal failure can increase the blood pressure?
Erythropoietin
Which parts of the vascular system has the most resistance? (Dr. Najeeb)
Arterioles
What will arteriolar constriction do to the blood pressure? (Dr. Najeeb)
Increase the diastolic blood pressure
What is the most potent arteriolar constrictor? (Dr. Najeeb)
Angiotensin II
Constrictors and Dilators that influence total peripheral resistance (Dr. Najeeb)
Constrictors:
Angiotensin II
Cathecolamines
Thromboxane
Dilators:
Nitric Oxide
Prostaglandins
Bradykinin
In the presence of epinephrine what will happen to blood vessels with alpha1 and beta2 adrenergic receptors? (Dr. Najeeb)
Alpha1 adrenergic : Vasoconstriction
Beta2 adrenergic: Vasodilation
Why does oral contraceptive increase risk of hypertension? (Dr. Najeeb)
Liver produces more angiotensinogen
Function of ANP
The main function of ANP is causing a reduction in expanded extracellular fluid (ECF) volume by increasing renal sodium excretion
