ELFH - cardiac challenges for dental practitioner Flashcards
What is often quoted as being ‘high’ BP?
consistent reading over 140/90mmhg
What time period should BP be measured over?
over a period of time
eg 7 days of home readings
essential hypertension?
In 80% to 90% of patients with hypertension, the cause is unknown. This is termed ‘essential hypertension’.
What factors are thought to be implicated in the development of essential hypertension?
obesity
alcohol
salt intake
stress
genetics
Secondary hypertension?
In 10% to 20% of patients, high BP is due to a number of rarer causes
What are the causes of secondary hypertension?
usually kidney dysfunction and hormonal disturbances (Cushing’s syndrome, Conn’s syndrome, phaechromocytoma)
Congenital cardiovascular disease (for example, coarctation of the aorta)
drugs (for example, oral contraceptive pill, steroids)
pregnancy are also implicated.
These cases are known as ‘secondary hypertension’.
isolated systolic hypertension?
The term ‘isolated systolic hypertension’ is associated with increasing age and with hyperthyroidism.
What is the pathogenesis of essential hypertension?
unclear
felt that changes in the sensitivity of specialised pressure receptors within blood vessels (baroreceptors) are involved.
These changes seem to lead to patients tolerating higher BPs than normal.
Longstanding hypertension affects?
arteries
heart muscle
kidneys and eyes
Effect of longstanding hypertension in small arteries and arterioles?
thicker walls and smaller lumens leading to increased total peripheral resistance
Effect of longstanding hypertension in larger arteries?
there is an increase in collagen and occasionally calcium deposition, which also increases total peripheral resistance
What is the risk of longstanding hypertension in arteries?
hypertension is a significant risk factor for the development of atherosclerosis, raising the risk of myocardial infarction and strokes.
What is the effect of longstanding hypertension to heart muscle?
results in an increase in the size of the heart muscle due to hypertrophic cardiac cell changes
This arises as the heart has to work harder to eject blood against the increased resistance.
This has implications for heart function and can predispose to the development of significant heart disease.
Effect of longstanding hypertension in the kidneys and eyes?
hypertension can also lead to damage to the microcirculation of the kidneys and to the eyes, resulting in kidney failure and visual impairment.
When is management of BP undertaken?
after an individual’s risk for cardiovascular disease has been ascertained.
What is the initial advise when a pt has been ascertained as being at risk of cardiovascular disease?
weight loss
low salt diet
moderation of alcohol intake
BP for hypertension?
> 180/120mmHg
Management of hypertension? (NICE)
treat urgently, assess for target organ damage and remeasure BP 7 days
BP for hypertension and CV risk?
140/90 to 179/119mmHg
BP for borderline hypertension and low risk CV risk?
Under 140/90mmHg over 120/80 mmHg
For hypertensive patients aged 55 or older, or pts of African and Caribbean descent of any age, what is the 1st choice for initial therapy?
should be either a calcium channel blocker (for example, amlodipine)
or a thiazide-type diuretic (for example, bendroflumethiazide).
For hypertensive pts younger than 55, what is the first choice of therapy?
an angiotensin-converting enzyme (ACE) inhibitor (for example, ramipril).
What is used if ACE inhibitors are not tolerated?
angiotensin II receptor antagonists (for example, losartan) can be used.
What are potential effects of antihypertensive drugs?
postural hypotension
xerostomia
gingival overgrowth
postural hypotension as a side effect of antihypertensives?
Where one’s BP falls on standing up with subsequent brief loss of consciousness.
This is especially seen when a patient gets up from the dentist’s chair.
Can be further exacerbated with the use of sedation during dental procedures.
xerostomia as a side effect of antihypertensives ?
Common side-effect of many antihypertensives.
Associated with an increased risk of caries and oral candidiasis
gingival overgrowth as a side effect of antihypertensives?
Rare side-effect of some calcium channel blockers, especially nifedipine.
This is associated with gum inflammation and plaque overgrowth
epinephrine 1:80,000 LA and what to do with a hypertensve pt?
infil is considered safe - as minimal epi enters blood stream due to enzyme breakdown
It is possible to observe a small but significant increase in blood pressure with epinephrine infiltration.
This has the theoretical potential to cause a hypertensive crisis, a medical emergency.
It is therefore recommended that hypertensive patients take their medication on the day of the dental procedure and ideally have their BP checked a few minutes following injection.
Always seek medical advice where there is any concern.
What BP is a contraindication for a dental procedure?
180/110mmHg - seek medical advice
Why does ischaemic heart disease occur?
Ischaemic heart disease (IHD) occurs when there is inadequate blood supply and, hence, oxygen supply to meet the demands of the heart muscle.
In the majority of cases, this is due to obstruction of blood flow in the coronary arteries supplying the heart (sometimes referred to as coronary artery disease).
The manifestations of IHD are dependent on the degree of this obstruction and its reversibility
The spectrum of IHD includes what?
stable and unstable angina
MI
Angina?
Angina is a result of an incomplete obstruction of blood flow to the heart, creating a reversible, hypoxic, acidotic cellular environment but with no permanent damage to the myocardium. This typically presents as crushing chest pain radiating to the left side of the mandible or left arm that resolves within minutes of either reducing demand of heart muscle or reducing how hard the muscle has to work.
Stable angina?
Where pain occurs to the same extent with similar amounts of exercise over a long period of time
unstable angina?
Where pain is experienced at rest or on minimal exertion
MI?
Myocardial infarction arises due to complete obstruction of blood flow in the coronary arteries to the myocardium. This leads to irreversible anoxic, acidotic cellular environments leading to muscle cell and tissue death
How does MI present itself?
This presents as angina-like pain that is more severe and persistent and is associated with sympathetic nervous system derived fright and flight symptoms, nausea, vomiting, fear and shortness of breath. The patient is often pale and clammy.
What are the 2 broad causes of IHD?
FOXED AND MODIFIABLE
What are non-modifiable factors leading to IHD?
Age
Gender
Family history or genetics
What are modifiable factors leading to IHD?
Hypertension
High cholesterol
Diabetes
Obesity
Excess alcohol consumption
In the majority of cases, what causes IHD?
ATHEROSCLEROSIS WITHIN THE WALL OF ARTERIES
What is atherosclerosis?
Atherosclerosis is characterised by the development of fatty plaques. These typically develop at sites of pre-existing arterial wall damage, such as that caused by hypertension, smoking and high blood cholesterol.
What do fatty plaques in the arteries also promote?
thrombus (blood clot development)
What can a thrombus development lead to?
leads to further reduction of lumen width which can lead to ischemia
- but some some thrombus can result n complete occlusion of the vessel, which can turn to infarction
What are the coronary arteries particularly prone to?
atherosclerosis
leading to IHD
