Clinical and pathological aspects of cardiovascular disease Flashcards
How many people in the UK are living with CV disease?
approx 7 million
Primary (essential) hypertension has multifactorial aetiology - name the 4 examples
- Genetic factors
- Environmental (e.g. obesity, alcohol, salt intake, stress)
- Humoral mechanisms
- Insulin resistance
What percentage of hypertension cases are primary hypertension (i.e. no cause found)?
90%.
Remaining 10% is secondary hypertension (i.e. cause found)
What value would be considered to be raised blood pressure?
> 140/90 mm Hg
Between what age is primary hypertension normally detected?
20-50 years of age
What could cause secondary hypertension? (5)
Renal disease
Pregnancy
Endocrine disease
Drugs (e.g. pill, corticosteroids)
Coarctation of the aorta (birth defect where part of aorta is narrower)
How would you diagnose hypertension?
Measure blood pressure on at least 3 occasions over 3 month period.
Patients often require 24 hr monitor
How would you treat secondary hypertension?
You would treat the cause if possible, as it is secondary
How would you treat primary/essential hypertension?
- General advice (6)
- Medical treatment (5)
1. Weight loss Increase exercise Reduce alcohol Stop smoking Reduce salt intake Increase fruit and veg intake
- (AABCD)
ACE inhibitors (e.g. captopril)
Angiotensin II receptor blockers (e.g. candesartan)
Beta blockers (e.g. atenolol)
Calcium channel blockers (e.g. nifedipine)
Diuretics (e.g. Bendroflumethiazide)
What are the complications of hypertension? (5)
Heart failure Stroke (cerebrovascular accident CVA) Coronary artery disease/myocardial infarction Renal failure Peripheral vascular disease
Outline the dental relevance of hypertension (7)
- Know to minimise stress and pain in order to minimise a further increase in BP (as this could then lead to CVA or MI)
- Can have LA with adrenaline (as long as IV injection avoided)
- Controlled hypertensive - treated as normotensive
- Uncontrolled hypertensive - delay elective treatment and refer to GP
- Severe hypertension - refer urgently to GP or hospital
- Post-operative bleeding more likely
- Patient likely to be taking aspirin
What measurements indicate uncontrolled hypertension?
> 140/90mmHg
What measurements indicate severe hypertension?
> 180/110 mmHg
Dental relevance of hypertension: what oral manifestations may arise if your patient is taking ACE inhibitors? (3)
Loss of taste
Angioedema
Lichenoid reactions
Dental relevance of hypertension: what oral manifestations may arise if your patient is taking beta blockers? (1)
Lichenoid reactions
Dental relevance of hypertension: what oral manifestations may arise if your patient is taking calcium channel blockers? (1)
Gingival overgrowth
Dental relevance of hypertension: what oral manifestations may arise if your patient is taking diuretics? (1)
Xerostomia
What is an intima/tunica intima?
It is the innermost layer of an artery or vein
Describe a normal intima (3)
<0.1 mm thick
Loose fibrous tissue
Endothelial layer on top
What is atherosclerosis?
It is a prevalent disease affecting large elastic and muscular arteries.
Intima thickens - composed of lipid derived from plasma and deposits of extra connective tissue
May calcify over time
Outline the possible locations of atherosclerosis (4)
Aorta
Carotid
Coronary arteries
More peripheral (e.g. legs of diabetics)
What are the possible complications of atherosclerosis? (7)
Rupture Ulceration Thrombosis Haemorrhage Calcification Aneurysm Embolus
Outline the stages of atherosclerosis (5)
- Endothelial dysfunction
- Formation of lipid layer or fatty streak within intima
- migration of leukocytes and smooth muscle cells into the vessel wall
- Foam cell formation
- Degradation of extracellular matrix (ECM)
Outline the progressive stages of endothelial dysfunction (6)
- Initial lesion: histologically normal, macrophage infiltration, isolated foam cells
- Fatty streak: mainly intracellular lipid accumulation
- Intermediate lesion: intracellular lipid accumulation, small extracellular lipid pools
- Atheroma: intracellular lipid accumulation, core extracellular lipid
- Fibroatheroma: single or multiple lipid cores, fibrotic/calcific layers
- Complicated lesion: surface defect, haematoma-haemorrhage, thrombosis
What are the consequences of familial hypercholesterolaemia on the levels of LDLs?
Increased levels of circulating LDL, due to the decreased receptors for LDL cholesterol (these cells aid in elimination via the liver)
LDL:HDL ratio - ideally, you never want this ratio to be above what level?
3-4:1
What is the purpose of HDL cholesterol in the blood?
It absorbs cholesterol and carries it back to the liver, where it is then eliminated from the body. High levels of HDL can lower risk of heart disease and stroke
Does the degree of atherosclerosis have a positive or negative correlation with hypertension?
Positive correlation
What happens in hypertension? (3)
Haemodynamic forces
Damage to endothelial cells and facilitating passage of LDL into intima
Coarctation (narrowing of aorta) of aorta findings
Outline the 3 factors that may contribute to advanced atherosclerosis
- Sex: mainly affects males until 7/8th decade, when protective effect of female sex hormone is lost
- Cigarettes: endothelial cell damage
- Diabetes: increased incidence of hyperlipidaemia and microvascular damage
What could happen in the event of advanced atherosclerosis? (4)
- Regression (improve the condition) - HDL, antioxidants
- Interference with blood flow to target organ (ischaemia/infarction)
- Thrombosis
- Embolisation
What is ischaemia?
Restriction in supply of blood to the tissues causing a shortage of oxygen and glucose necessary for cellular metabolism
What is infarction?
It is tissue death caused by a lack of oxygen due to obstruction in blood flow
What are the clinical symptoms of ischaemia? (3)
Angina
Transient ischaemic attack (TIA)
Peripheral vascular disease (Intermittent claudication) - pain in thigh, calf or bum when you walk i.e. reduced blood flow to your legs
What are the clinical symptoms of infarction? (3)
Myocardial infarction
Stroke
Gangrene
What 4 things are important to consider in atherosclerosis?
Collateral blood supply
Speed of arterial occlusion
Metabolic needs of tissue
Degree of arterial blocking
Outline the clinical aspects of IHD (ischemic heart disease i.e. angina, MI) (3)
Inadequate oxygen supply to meet demands of heart
Atheromatous plaque within coronary arteries causing constriction to blood flow
Risk of plaque rupturing leading to acute thrombus and MI
What are the unmodifiable risk factors of Ischemic heart disease? (3)
Age
Male gender
Family history
What are the modifiable risk factors of Ischemic heart disease? (9)
Hyperlipidaemia Smoking Hypertension Diabetes Obesity Lack of exercise High alcohol intake Stress OCP (oral contraceptive pill)
What is angina and what are the signs?
Angina is reduced oxygen perfusion of cardiac muscle
Strangling feeling in chest, breathlessness, pain radiating to jaw and left arm (pain resolves in minutes following rest and GTN)
What do you need to consider with angina - what is the dental relevance? Give examples (3)
Polypharmacy: Side effects of these meds - how they affect the patient and what you plan to do to them.
Aspirin - tendency to bleed
Beta blockers/calcium channel blockers - mucosal disease
Nicorandil - oral ulceration
What are the symptoms of myocardial infarction? (3)
Central strangling pain lasting longer than 15 minutes
Pain radiates to neck, jaw and left arm
Nausea, vomiting
What are the signs of MI? (3)
Grey tinge
Sweating
Tachycardia
What steps do you take to manage myocardial infarction? (7)
- Sit patient up
- Stay calm and relaxed
- Dial for an ambulance
- Administer oxygen and GTN (repeat every 10 minutes)
- Aspirin 300mg PO crushed or chewed
- Entonox if available
- Monitor pulse and oxygen saturation
In what ways may myocardial infarction be relevant in a dental scenario? (6)
- Dental treatment may precipitate angina/MI - need to minimise stress and pain
- May present as jaw pain
- May use GTN prophylactically
- Unstable angina - delay elective treatment until controlled
- Likely to be taking aspirin
- Oral manifestations of drugs - Ca channel blockers (gingival overgrowth), beta-blockers (lichenoid reactions), nicorandil (oral ulceration)
What is the main, important difference between clotting and thrombosis?
Clotting occurs when there has been tissue injury, whereas, thrombosis occurs at the wrong time and wrong place, so it is harmful
Outline clotting
Essential, physiological and beneficial activation of clotting cascade when there has been tissue injury.
Refers to activation of protein cascade leading to formation of fibrin
Outline thrombosis:
- what is activated?
- what happens?
Involves activation of both platelets and clotting cascade
Haemostasis occurs in the wrong place at the wrong time. This is harmful.
What are the 3 factors involved in Virchow’s triad? (factors that promote thrombosis)
- Changes in surface of blood vessel (endothelial injury)
- Changes in blood flow (stasis of blood flow)
- Changes in constituents of blood (hypercoagulability)
Describe how the blood vessel surface may change in Virchows triad (7)
- Atheromatous plaque
- Splitting/fraying/loss of surface endothelial cell layer
- Exposure of sub-endothelial tissues (fibrous/fatty plaque) leads to platelet activation
- burning/freezing “frostbite” causes trauma to the endothelium
- Mechanical: indwelling cannulae
- Chemical injury: injectable materials (sometimes deliberate)
- Inflammation “vasculitis”
Outline how the pattern of blood flow can change in Virchow’s triad
DVT (deep vein thrombosis)
Embolus (when part of clot breaks off and travels)
Congestive heart failure (venous stagnation) Post myocardial infarction Atrial fibrillation Heart valve disease Arterial vs. venous thrombosis Turbulence vs. speed
Outline the changes in the blood constituents in Virchow’s triad
Hypercoagulable state: haemostatic equilibrium is tilted in favour of thrombosis:
- Increase pro-coagulant factors
- Pro-coagulant factors from malignant tumours
- Decrease in anti-coagulant factors
- Increased platelet count and adhesiveness/aggregability
- Increased viscosity of the blood
Name groups of patients that are said to have increased fibrinogen and factor VIIc concentrations? (6)
Increasing age Obesity Oral contraceptives Menopause Diabetes Smoking
Name the 3 possible fates of a thrombus
Lysis
Organisation/recanalisation
Embolisation
What is embolisation? (2)
Thrombi detach and travel at high speed through the circulation
Until a vessel is reached whose lumen is smaller than the size of the thrombus
What are the 5 types of emboli - which one is most common?
Thrombus (99%) Infective (vegetations of infective endocarditis) Gaseous Fat Foreign material
What are the clinical aspects of heart failure?
Pump failure e.g. heart muscle disease, restricted filling, inadequate heart rate
Excessive preload e.g. mitral regurgitation, fluid overload
Chronic excessive afterload e.g aortic stenosis (narrowing of valve), hypertension.