Myocardial Infarction - STEMI and NSTEMI Flashcards
Acute coronary syndrome (ACS) is usually the result of a thrombus from an atherosclerotic plaque blocking a coronary artery. When a thrombus forms in a fast-flowing artery, it is formed mainly of platelets. This is why antiplatelet medications such as aspirin, clopidogrel and ticagrelor are the mainstay of treatment.
There are three types of acute coronary syndrome:
Unstable angina
ST-elevation myocardial infarction (STEMI)
Non-ST-elevation myocardial infarction (NSTEMI). What is the incidence of ACS?
1 - 2 cases per 100,000
2 - 20 cases per 100,000
3 - 200 cases per 100,000
4 - 2000 cases per 100,000
3 - 200 cases per 100,000
More common in men
STEMI is the most common of the 3
What age does the incidence of acute coronary syndrome peak at?
1 - 40-50
2 - 50-60
3 - 60-70
4 - >75
3 - 60-70
Acute coronary syndrome is a condition that develops over a number of years. Which of the following is a risk factor that can be modified?
1 - Increasing age
2 - Male gender
3 - Diabetes
4 - Family history
3 - Diabetes
Acute coronary syndrome is a condition that develops over a number of years. Which of the following is risk factors that cannot be modified?
1 - Increasing age
2 - Smoking
3 - Diabetes mellitus
4 - Hypertension
5 - Hypercholesterolaemia
6 - Obesity
1 - Increasing age
Acute coronary syndrome (ACS) generally develops in patients who have ischaemic heart disease (IHD), a term synonymous ACS. It describes the gradually build up of fatty plaques within the walls of the coronary arteries. This leads to two main problems:
1 - Gradual narrowing =
- less blood and oxygen reaching the myocardium
- exertion increases blood and oxygen demand that myocardium cannot provide
- angina presents as chest pain due to lack of oxygen reaching the myocardium
2 - Risk of sudden plaque rupture =
- fatty plaques build up in the endothelium
- increased risk of rupture that can lead to rupture and sudden occlusion of the artery
- occlusion means no blood/oxygen reaches that specific part of the myocardium.
What is the earliest stage of atherogenosis (atherosclerotic plaque formation, leading to coronary artery heart disease)?
1 - fatty streaks
2 - LDL infiltration
3 - cytokine release
4 - foam cells build up
1 - fatty streaks
Coronary atherosclerosis is a complex inflammatory process. Although the exact cause is unknown, the trigger id commonly linked with damage and/or dysfunction to the epithelium of blood vessels. Which of the following has not been identified as a trigger causing epithelium damage and/or dysfunction?
1 - morbid hypertension
2 - biochemical abnormalities (LDL)
3 - diabetes mellitus
4 -immunological factors (free radicals from smoking)
5 - inflammation
6 - genetic alteration
7 - biochemical abnormalities (HDL)
7 - biochemical abnormalities (HDL)
Following the initial damage/dysfunction to blood vessel epithelium, what is the first things that occurs leading to coronary atherosclerosis?
1 - increased cytokine expression
2 - foam cells build up
3 - LDL cross epithelium
4 - macrophages phagocytose LDL through oxidation
3 - LDL cross epithelium
Following the initial damage/dysfunction to blood vessel epithelium, LDL cross the epithelium. What then occurs leading to coronary atherosclerosis?
1 - increased cytokine expression
2 - foam cells build up
3 - LDL cross epithelium
4 - macrophages phagocytose LDL through oxidation
4 - macrophages phagocytose LDL through oxidation
- macrophages cross endothelium to get to LDLs
Following the initial damage/dysfunction to blood vessel epithelium, we have dead macrophages full of LDLs, called foam cells. What is the next thing that occurs leading to coronary atherosclerosis?
1 - increased cytokine expression
2 - foam cells build up
3 - LDL cross epithelium
4 - macrophages phagocytose LDL through oxidation
2 - foam cells build up
- foam cells are macrophages that have died and begin secreting cytokines
- attract more monocytes to area
What is a fatty streak, which is a term used in atherosclerosis?
1 - build up of HDL beneath epithelium
2 - build up of LDL beneath epithelium
3 - build up of foam cells beneath epithelium
4 - build up of macrophages beneath epithelium
3 - build up of foam cells beneath epithelium
Fatty streaks can occur in any patients throughout their life. Why are fatty streaks dangerous?
1 - thrombogenic
2 - increase blood pressure
3 - increase cytokine release
4 - decrease HDL levels
1 - thrombogenic
- susceptible to blood clotting on it
Fatty streaks formed by dead macrophages containing LDL are thrombogenic, meaning they are susceptible to blood clotting. This causes the release of platelet derived growth factor, and then smooth muscle migration and proliferation to the tunica intima from the tunica media. Smooth muscle cells then secretes things that become the fibrous cap. Which of the following is NOT a component of the fibrous cap?
1 - collagen
2 - elastin fibrous cells
3 - elastic cartilage
4 - proteoglycans
3 - elastic cartilage
- purpose of the fibrous cap is to prevent blood clotting
Together the fibrous cap and fatty streak are called what?
1 - thrombosis
2 - embolus
3 - atheroma
4 - plaque
4 - plaque
In addition to secreting the contents that make up the fibrous cap, what else do smooth muscle cells secrete in the fatty streak?
1 - Ca2+
2 - Na+
3 - Mg+
4 - Cl-
1 - Ca2+
- normally deposited into vessel walls by LDL
- cholesterol crystals are also present
In addition to secreting the contents that make up the fibrous cap, smooth muscle cells secrete Ca2+ into the fatty streak, which is normally deposited into the vessel walls by LDL. Normally what then removes the Ca2+ to stop the hardening of blood vessel walls?
1 - lipoprotein lipase
2 - HDL
3 - VLDL
4 - albumin
2 - HDL
- plaques impair HDLs ability to remove Ca2+
Once Ca2+ has been deposited into the fatty streak and vessel walls, do the vessel walls become more elastic or stiff?
- stiff due to Ca2+ forming crystals
What generally causes a myocardial infarction that has been in the arteries for some time?
1 - low nitrates
2 - increased Na+ and K+
3 - fibrous cap of plaque becomes unstable and ruptures
4 - endothelium become damaged and leak collagen
3 - fibrous cap of plaque becomes unstable and ruptures
- rupture is due to thinning of the cap and core expansion
- thrombogenic contents (foam cells) of plaque leak out causing blood clot
During the rupture of fibrous cap or the expansion of a plaque, what % of blood vessel occlusion can lead to stenosis and lead to ischaemia given any increase in O2 demand?
1 - 10%
2 - 30%
3 - 50%
4 - 70%
3 - 50%
- 50% reduction in luminal diameter causes a 70% reduction in luminal cross-sectional area
As fatty streaks form in the endothelium, platelets bind to damaged epithelium. They then release platelet derived growth factor that drives the development of what?
1 - more macrophages migrate to the area
2 - lymphocytes are activated
3 - smooth muscle cell proliferation
4 - increased cytokine secretion from fatty streak
3 - smooth muscle cell proliferation
- smooth muscle cells move from tunica media to tunica intima
When plaques rupture, what is the primary content that is very atherogenic that leaks out causing the formation of red thrombus?
1 - collagen
2 - Ca2+
3 - foam cells
4 - smooth muscle cells
3 - foam cells
- thrombus is blood clot
- embolism is clot moving in blood
Once a plaque ruptures a red thrombus is formed. This thrombus may cause the following:
- occlusion of the artery
- partial occlusion of the artery
- embolise distally
- plaque progression
Match the above with the following: ST elevated MI, Non-ST elevation MI, stable angina and unstable angina:
- ST elevated MI = occlusion of the artery
- Non-ST elevation MI = partial occlusion of the artery
- stable angina = embolise distally
- unstable angina = plaque progression
Which of the following is a typical clinical feature of a patient presenting with acute coronary syndrome?
1 - left sided chest pain (pressure, tightness, or crushing sensation)
2 - radiating pain to the left arm, jaw, or neck
3 - dyspnoea
4 - nausea and vomiting
5 - sweating (response to pain)
6 - palpitations
7 - all of the above
7 - all of the above
Patients may also appear anxious, restless, or diaphoretic due to sympathetic activation.
Cyanosis may be present in severe cases, indicating hypoxia.
Which of the following would be recognised as atypical symptoms of an acute coronary syndrome?
1 - epigastric pain
2 - fatigue
3 - syncope or pre-syncope
4 - all of the above
4 - all of the above