Pathology Ischaemic Heart Disease and Hypertension Flashcards
Virchow’s triad
Change in vessel wall structure
Change in blood flow
Change in blood constituents
Laminar flow maintains
healthy movement of blood through vessels
Collagen formation on endothelia occurs after
Allows
This leads to
Fibrinogen is
Damage by cholesterol
Platelet attachment
Further platelet aggregation and release of clotting factors
Polymerised into fibrin –> blood clot –> thrombus formation
Causes of ischaemic heart disease
Lack of blood supply
Atherosclerosis
Myocardial hypertrophy
Small vessel disease
Ischaemic heart disease
Disease involving narrowing of vessels supplying blood to heart muscle due to accumulation of fatty plaque
Risk factors of atherosclerosis and explain
High salt+fat diet Sedentary lifestyle Smoking High BP - shearing of endothelial cells Poorly controlled diabetes Hyperlipidaemia - abnormally high concentration of fats or lipids in blood High blood sugar and lipids Continuing damage to endothelium
Characteristics of atherosclerosis
Bleeding within plaque build up due to collapse of new fragile vessels
Slow
Consistent damage over time
Death of heart muscle results
Myocardial hypertrophy
Affects
Left ventricle
LV has to work harder to pump blood due to increased thickness of heart muscle
Small vessel disease
Occurs at
Involves
Arteriolar level
Inappropriate vasoconstriction
Reduced production of nitric oxide and increased destruction of nitric oxide
Types of IHD
Regional transmural MI
Subendocardial MI
Chronic ischaemia
Regional transmural MI
Supply to certain region cut off due to blockage of after
Acute occluding event in one of 3 CAs
Lack of collateral circulation from other vessels
Subendocardial MI
Supply cut off inside of cardiac structure e.g LV
Severe coronary artery atherosclerosis in all 3 main CAs
Sudden reduction in blood flow e.g hypotension during surgery
Chronic ischaemia
Fixed atherosclerotic lesions Angina Myocardial fibrosis Hibernating myocardium Stunned myocardium
Complications of MI
Sudden death Arrhythmias Cardiac failure Mitral incompetence Pericarditis Cardiac rupture Mural thrombosis Ventricular aneurysm Pulmonary emboli
Sudden death explanation
Inadequate blood flow
Arrhythmias e.g ventricular fibrillation
Cardiac failure explanation
Arrhythmia
Loss of myocardium - reduced pump fx
Mitral incompetence cause
Rupture/necrosis of papillary muscles
Pan systolic murmur
Cardiac rupture explanation
Occurs when
Weakening of wall due to muscle necrosis and acute inflammation
3-7 days after infarction
Rupture in pericardial sac
Rupture of inter ventricular septum
Mural thrombosis
When does it occur
What does it lead to
Thrombosis on normal endothelial surface post infraction
7-14 days after infarction
embolisation to any arterial site
Ventricular aneurysm
When does it occur
Associated with?
May contain?
Stretching of newly formed collagenous scar tissue
4 weeks post infarction
Cardiac failure
Thrombus
Hypertension
At 20 y/o
At 50 y/o
Abnormally high BP
>140 mmHg systolic and <90 diastolic
>159 mmHg systolic and <95 diastolic
Clinical importance of hypertension
Most common cause of heart failure
Major risk factor for atherosclerosis
Major risk factor for cerebral haemorrhage
Classification of hypertension and define
Primary - no definitely identified cause
Secondary - identifiable cause
3 factors involved in primary hypertension
Adrenaline
Sodium control
Renin angiotensin aldosterone - RAAS
Causes of secondary hypertension
Renal
Endocrine
Coarctation of aorta
Drug therapy
Coarctation of aorta
Narrowing of aorta
Causes of secondary hypertension - renal
Salt and water overload
Renin dependent
Causes of secondary hypertension - endocrine
Cushing’s, Conn’s, phaeochromocytoma (rare tumour of adrenal glands)
Phaeochromocytoma
Tumour on adrenal glands
Overproduction of catecholamines –> sweating, racing heart, hypertension
Causes of secondary hypertension - drug therapy
NSAIDs, corticosteroids
Clinicopathological classifications - two
Benign
Malignant
Clinicopathological classifications - benign
Long asymptomatic period
Increased frequency of complications later on
Clinicopathological classifications - malignant
Significantly raised diastolic BP
Symptomatic
Rapidly fatal if untreated
Effects of hypertension - vessel
Microaneurysms and haemorrhages
Accelerated atherosclerosis
Athersclerosis of other smaller vessels
Effects of hypertension - organ
Heart failure
Kidney failure
Cerebral haemorrhages aka strokes
