PH2113- Cardiovascular 2 Flashcards
explain the RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM
Renin is an enzyme secreted into the blood:
which catalyzes the conversion of a plasma protein, angiotensinogen into angiotensin I.
An enzyme angiotensin-converting enzyme (ACE) then converts angiotensin I into angiotensin II. Angiotensin II has several effects:
-acts via receptors in the adrenal glands to stimulate the secretion of aldosterone, which stimulates salt and water reabsorption by the kidneys.
-vasoconstriction of the arterioles= an increase in blood pressure. Angiotensin II.
WHY WORRY ABOUT HYPERTENSION?
-Hypertension is almost always asymptomatic until
end-organ disease occurs (“a silent killer”)
The primary aim of anti-hypertensive therapy is to reduce BP to a level that reduces morbidity/mortality
risk level reduction
prevention, or if possible, reversal of end organ disease
ATHEROSCLEROSIS IN DIFFERENT ARTERIES (arteries become clogged with fatty substances)
coronary arteries RESULTS IN: Ischaemic heart disease (CAD) angina, myocardial infarction
Cerebral arteries (brain) = cerebrovascular disease (CVD) & carotid arteries stroke, vascular dementia
renal arteries: renovascular disease
aorta: aortic (swelling) aneurysm arotuddenly ruptures
legs and arms: claudication (extreme discomfort when people walk or do e, peripheral gangrene
“HYPERTENSIVE HEART DISEASE”
- No. 1 cause of death associated with high blood pressure.
may include any or all of the following:
-Structural changes to myocardium (LVH)
-Coronary artery disease,
conduction system
-Disturbances
- Valvular dysfunction
May be associated with any or all of the following:
Diastolic and systolic heart failure
Ischaemic heart disease
Cardiac arrhythmias, incl. sudden death due to VF aortic/mitral regurgitation.
PULMONARY CIRCULATION
Deoxygenated blood away from the right side of the heart, to the lungs
Pulmonary hypertension
pulmonary vessels are the blood vessels that supply the lungs.
An increase in blood pressure in any part of the pulmonary circulation
Arterial, venous, capillary (or all)
Usually secondary to some other pathological or environmental condition
Rare forms:
- Pulmonary arterial hypertension of unknown cause (idiopathic pulmonary hypertension)
- familial (relating to or occurring in a family) pulmonary hypertension
PULMONARY HYPERTENSION CLASSIFICATION- go into detail further later on
- Pulmonary arterial hypertension
- Pulmonary venous hypertension resulting from
left heart disease - Pulmonary hypertension resulting from lung
diseases and/or hypoxia (deficiency of O2 reaching the tissues)
4.Pulmonary hypertension due to chronic
thrombotic and/or embolic disease
- Pulmonary hypertension of miscellaneous origin
PULMONARY HYPERTENSION CLASSIFICATION- go into detail further later on
- Pulmonary arterial hypertension
- Pulmonary venous hypertension resulting from
left heart disease - Pulmonary hypertension resulting from lung
diseases and/or hypoxia (deficiency of O2 reaching the tissues)
4.Pulmonary hypertension due to chronic
thrombotic and/or embolic disease
- Pulmonary hypertension of miscellaneous origin
Primary and secondary PULMONARY ARTERIAL HYPERTENSION
Arteries connecting the heart to the lungs on the right side.
Primary:
- idiopathic/cause is unknown
- Familial
Secondary
- PAH associated with many other conditions
These form the majority of cases of PAH.
FAMILIAL PAH even more rare: early presentation often in infancy
and equal gender distribution.
- PATHOLOGY (diagnosis of disease ) OF IDIOPATHIC Pulmonary Arterial Hypertension
- Increased vascular resistance (pulmonary vasoconstriction
Vascular resistance is the resistance that must be overcome to push blood through the circulatory system and create flow). - Proliferative / coagulative pulmonary arteriopathy
medial/intimal hyperplasia
vascular fibrosis
thrombosis/platelet aggregation.
Treatment of IDIOPATHIC Pulmonary Arterial Hypertension
A lethal condition without treatment life expectancy is 2-3 years in IPAH death from heart failure (cor pulmonale) or sudden arrhythmic death
Conventional IPAH therapy includes:
- Inhaled O2
- Oral anticoagulants
- Diuretics
High-dose calcium channel blockers
effective only for a small minority
newer vasodilator agents
What is the BMPR2
-possible genetic basis for Familial PAH (Pulmonary Arterial Hypertension)
-Mutation of gene (BMPR2) encoding
bone morphogenetic protein receptor-2
-Inherited as an autosomal dominant disease
BMPs part of TGF-b superfamily of ligands (involved in paracrine signalling)
-Thought that BMP/BMPR-II signalling normally regulates cell growth and apoptosis in pulmonary vascular cells
Some evidence of decreased BMPR2 expression in secondary pulmonary arterial hypertension.
COR pulmonale
Alteration in the structure and function of the right ventricle (enlargement of the right ventricle).
Right-sided heart failure as a consequence of increased pulmonary artery pressure.
Right ventricular hypertrophy (chronic growth) right ventricular dilatation (acute stretch)
- It is right ventricular failure as a result of increased pulmonary artery pressure
- Results in: Peripheral oedema (accumulation of fluid causing swelling in tissues), dyspnoea (difficult breathing). fatigue
- Most common cause of hospitalisation in all patients with Pulmonary Hypertension (1o or 2o)
- PULMONARY VENOUS HYPERTENSION
- This form is caused by diseases of the left side of the heart, such as heart failure or mitral valve disease
(i. e almost always secondary to left heart disease)
Imposes a haemodynamic overload on the pulmonary venous circulation. fluid dynamics of blood flow.
- PATHOLOGY AND TREATMENT OF PULMONARY VENOUS HYPERTENSION
Initially, no increased resistance to blood flow in the pulmonary arterial circulation
But decreased pulmonary venous drainage leads to increased pulmonary blood volume and increased “back pressure” throughout the pulmonary circulation
Chronic PVH may lead in time to pulmonary vascular structural changes and increased vasoconstriction/PAH
Treatment is to correct any structural defect
(e.g. mitral valve surgery) or optimise left ventricular function (e.g. ACE inhibitors, diuretics, spironolactone,
b-adrenoceptor antagonists)
