IHD and ACS Flashcards
What is ischaemic heart disease?
heart problems caused by narrowing of the arteries
narrowing of the arteries leads to less blood and oxygen reaching the heart (therefore affects coronary arteries)
Ischaemic heart disease is also referred to as …
coronary artery disease
coronary heart disease
Ischaemic heart disease is a spectrum of diseases which include:
stable angina
unstable angina
myocardial infarction
Acute coronary syndrome refers to a group of conditions that include…
ST elevations myocardial infarction
Non-ST elevation myocardial infarction
Unstable angina
Angina presents as a “pain in the heart”. Describe the pathophysiology of angina
cells do not have enough oxygen and so switch to anaerobic respiration; leading to the production of lactic acid (from pyruvate)
Build up of acid in the heart tissue causes pain
What are some risk factors for ischaemic heart diseases (IHD)?
diabetes
obesity
hypertension
smoking
What is a risk factor for atherosclerotic changes to the blood vessels?
high blood pressure
Outline the aetiology of IHD
Endothelial injury (lining of vessels can be damaged by high blood pressure)
the endothelium becomes exposed to LDL, hormones and pro-inflammatory molecules (smoking)
Expression of adhesion molecules (expression of adhesion molecules is up-regulated in damaged endothelium
leukocytes then adhere to the artery wall (via adhesion molecules) as part of the inflammatory response to the damaged endothelium
Monocytes scavenge lipids and then become foam cells (characteristic of atheroma)
Foam cells release cytokine to stimulate smooth muscle migration in to the media - formation of the fatty streak [smooth muscle cell hyperplasia- further narrowing the blood vessels]
Deposition of lipoprotein in the intima leads to plaque
Obstruction due to plaque, clot or vasospasm
What is the consequence of an atheroma encouraging the splitting of the endothelium ?
subendothelium is exposed
platelet plug formation
thrombus is formed
What is an arterial stenosis?
narrowing of the artery
What causes angina?
this is when the myocardial oxygen demand exceeds the myocardial supply
Give instances where myocardial oxygen demand increases
emotional stress
increased physical activity
sexual activity
How is myocardial oxygen supply assessed?
coronary blood flow
arterial O2 content
Angina is a ___________ cellular hypoxia
reversible
Infarct is an _____________ condition with dead muscle present. What leads to an infarct ?
irreversible
complete blockage of the coronary artery
List IHD presentation
typical angina
atypical angina
asymptomatic
epigastric pain
jaw/arm pain (left arm, left side of jaw)
fatigue
dyspnoea on exertion
tachycardia
xanthelasma
retinopathy
Delayed healing in pulp/periodontum due to poor circulation
What is xanthelasma?
local accumulation of lipid deposits on eyelids
Give the characteristics of typical angina
chest pressure/squeezing lasting several minutes
provoked by exercise or stress
relieved by rest or GTN
What are the clinical presentations of a myocardial infarct?
sweating
tachypnea
anxiety (fight or flight)- impending feeling of doom
Pale skin
no GTN relief
What are the clinical investigations for IHD?
Resting ECG
Haemoglobin (make sure that they are not anaemic)
Fasting lipid profile
Fasting blood glucose
coronary angiography
What is the presentation of angina on an ECG
ST depression
[there should be a straight line between the S and T segments of the ECG]
How is IHD managed for all patients?
lifestyle education
antiplatelet therapy (prevent thrombus which narrows arteries)
anti-anginal therapy
statin (lipidaemia, atheroma)
anti-HTN therapy- prevent damage to the endothelial layer of the blood vessels
CABG (coronary artery bypass graft, to bypass obstruction and supply cells in region)/PCI
BM control ? bone marrow??
What is the management of acute anginal symptoms ?
sublingual GTN
ST elevation in ECG is usually an indication of…
infarct
ST depression in ECG is usually an indication of …
angina
What is unstable angina?
absence of biochemical evidence of an MI
angina lasts >20 minutes
angina at rest (pain at rest)
crescendo angina
What is a myocardial infarction (non-ST elevation)?
an acute ischaemic event causing myocyte necrosis
no ST elevation on the ECG
What is a myocardial infarction (ST- elevation)
acute ischaemic event causing myocyte necrosis
evidence of ST elevation on the ECG
What is the biochemical evidence of a myocardial infarct?
when a muscle dies, various enzymes are releases
However in angina, muscle cells do not die which means enzymes are not releases hence no biochemical evidence being present
What is the clinical presentation acute coronary syndrome?
angina
radiation to jaw/arm
pallow
dyspnoea
cardiogencic shock- cannot meet the demands of the body- body not getting enough blood flow
nausea and vomiting
sweating
feeling of impending doom
tachycardia
hypotension
epigastric shock may also occur- pain goes through to the back
Outline the pathophysiology of ACS
rupture of fibrous plaque
exposure of lipid substances
platelet aggregation
thrombus formation
occlusion of vessel
ischaemia (reduction of oxygen) and myocardial necrosis
What are the clinical investigations to determine ACS?
ECG
cardiac biomarkers (dead muscles leak enzymes)
coronary angiogram
serum, lipids, glucose, U&Es (urea and electrolytes)
Give examples of cardiac biomarkers of infarcts
Troponin
Creatine kinase (CK)
CK-MB (isoenzyme of creatine kinase)
What is the presumptive management of ACS?
[MONA]
Morphine- switches off sympathetic nervous system, also for pain
Oxygen
Nitrates (for pain - [acid relief?])
Aspirin (300mg)
employ DR ABC
What is the definitive management of ACS?
percutaneous coronary intervention (PCI)- stent
anticoagulation (warfarin)
antiplatelet (forever)
statin
thrombolysis
When should thrombolysis be performed?
if PCI is not available in 90 minutes
if a stent is not placed in 90 minutes
PCI (stent) delays …
(pushes back) the need for CABG
What is the disadvantage of a stent placed in vein ?
veins are not meant to undergo arterial pressure
they will eventually narrow
What are the dental considerations for stable angina
[angina can be provoked by pain and anxiety- emotional stress]
no issues with minor treatment under LA
consider oral sedation, [BZD?]
anything larger than minor treatment, deal with cardiology team
What are the dental considerations for unstable angina?
higher risk of MI
always discuss with cardiology team prior to treatment, prophylactic GTN
What are the dental considerations post myocardial infarction?
most complications occur within 6 months (high re-infarction rate)
defer treatment where possible
