Acute coronary syndrome - Patterson Flashcards
What is CAD or coronary artery disease?
Narrowing of coronary arteries due to arteriosclerosis.
What factors increase risk for CAD?
- smoking
- obesity
- hypertension
- hyperlipidemia - especially high LDL with low HDL
- sedentary lifestyle
- older age - greater than 65
- hyper and hypothyroidism
- diabetes
- male gender
- positive family history
Describe the epidemiology of CAD.
CAD effects 82 million Americans and causes approximately 33% of all deaths in the US
Total Healthcare inpatient cost for CAD is $72 billion or ¼ of all healthcare costs
Prevalence of CAD increases with age. 7.5% for men and women 45-60 and 19.8% for those over age of 65. Average age of onset for women is 72 and for men 62
Prevalence in whites 6.4%, blacks 6.7, Hispanic/Latino 5.8. Lower rates in Asians and Native Americans 3.9 and 4.1
What is atherosclerosis?
- a type of arteriosclerosis
2. deposits of lipids, macrophages, calcifications in arteries leading to plaque formation
What is the greatest risk factor for CAD?
Age. If you are over age 70 then your risk score is above 20% automatically.
Describe acute coronary syndrome.
Any group of clinical syndromes consistent with myocardial ischemia (or patients with symptoms suggesting an unstable cardiac condition due to ischemia)
It’s a spectrum of conditions resulting in myocardial ischemia including unstable angina (UA), NSTEMI and STEMI
Secondary (usually) to ruptured plaque or erosion of a plaque leading to thrombus formation and secondary partial or complete occlusion of the vessel
Describe unstable angina.
- Reversible ischemia
- Sudden onset at rest or change in frequency or severity of baseline angina
- +/- EKG changes of T wave inversion or ST depression
- Biomarkers are not elevated due to lack of necrosis to myocardium
- new chest pain is considered to be unstable angina even if it only occurs during exertion
Describe NSTEMI.
- non ST elevation MI
- symptoms indistinguishable from UA
- Usually has EKG changes- ST segment depression and T wave inversion
- Biomarkers are elevated due to damage to myocardium
What is a STEMI?
- ST elevation MI
- is a clinical emergency
- diagnose with clinical presentation and EKG criteria
- patient sent to cath lab before cardiac biomarker labs are back
What are the urgent causes of chest pain?
- aortic dissection
- pulmonary embolism
- tension pneumothorax
- esophageal rupture
What some non-urgent causes of chest pain?
- pneumonia
- pleurisy
- pericarditis
- myocarditis
- hypertrophic cardiomyopathy
- PUD
- GERD
- esophageal spasm
- panic attack
- biliary or pancreatic disease
What are some high yield parts of the H & P for determining the likelihood of ACS?
- nature of chest pain - OLDCARTS
- prior history of CAD
- gender/sex
- age
- number of traditional risk factors for CAD
What percentage of patients with ACS present without chest pain?
25-30%
What is the typical presentation of chest pain in those with ACS?
heavy’ or ‘pressure’ sensation in the sternum or epigastrium
Radiates to jaw, neck, throat, back or left arm
Lasts at least 15-20 minutes
Not relieved by rest
What is the atypical presentation of chest pain in those with ACS?
sharp or stabbing pain
Pain reproduced by movement of arms or by touch
Pain that lasts for seconds
Pain described as heartburn or burning in nature
Women with ACS are more likely to have what?
Pain in the jaw and neck rather than chest pain.
Older patients with ACS have less what than younger patients?
Complaints of chest pain.
Pain to both shoulders increased the likelihood of MI how much in one study?
7 fold
What is normal in a majority of cases with ACS?
The physical exam.
What are some red flags to look for evidence of cardiomyopathy with a STEMI?
- S3
- pulmonary rales
- JVD
- hepatojugular reflex
- diminished pulses
- hypotension
EKG’s are necessary for diagnosis but in what percentage of acute MI patients is the EKG normal or non diagnostic?
20-55% of patients
Are T wave inversion and ST elevation specific for MI?
No. Pericarditis, myocarditis and ventricular aneurysm can all cause ST elevation. T wave inversion can occur with Tricyclic use and strokes.
Can you differentiate UA from a NSTEMI by EKG?
No. You would need cardiac biomarker information for this.
What are the most sensitive and specific biomarkers for evidence of MI?
- Troponin I and T
- specific for cardiac tissue
- present in circulation within 2 hours of event and not elevated until about 8-12 hours but have relatively low sensitivity until 6 hours
- remain elevated up to 5-14 days
Although troponins are specific for cardiac tissue they are not specific for an MI. What are some other conditions that may cause elevated troponins?
- renal disease
- tachycardia/afib
- myocarditis/pericarditis
- severe cardiomyopathy
- GI bleed
- stroke
- pulmonary embolism
The positive predictive value for MI with elevated troponins changes with what?
Prevalence of disease. Would be lower in a 35 year old patient with chest pain than in a 72 year old patient with chest pain and a history of hypertension and ischemic heart disease - especially if the troponin level is greater than 1.0 ng/ml. The higher the troponin level, the higher the risk for ACS.
What is another cardiac biomarker?
CKMB.
- can be detected within 2 hours
- undetectable at 72 hours post event
- if initially negative, recheck every 6-9 hours
- specific but not sensitive
What are the principles of treatment for UA/NSTEMI?
- bed rest
- continuous cardiac monitoring
- relief of ischemia - can use nitro, or morphine and a beta blockade and calcium channel blocker
- may possibly also give antithrombotics and anticoagulants
- angiography may be considered in patients with refractory chest pain or electrical instability or in patients who are stabilized but at high risk for clinical events
After UA/NSTEMI there is increased risk for what?
V-fib.
Describe treatment of STEMI.
1/3 of patients with STEMI die within the first 24 hrs of ischemia
Goal is to provide URGENT treatment by restoring blood flow to occluded vessel:
Fibrinolytic therapy – Glycoprotein 2b/3a inhibitors
Heparins
Percutaneous coronary intervention (PCI)
Coronary artery bypass grafting (CABG)
What can be done for prevention of ACS?
A Aspirin, antiplatelet agents, ACEIs/ARBs B Beta blockers and blood pressure control C Cardiac rehab (if applicable), cigarette smoking cessation and cholesterol management D Diet, diabetes control and depression management E Exercise and education
