Cardiology Labs (EXAM 4) Flashcards
What is included in a lipid profile?
Total cholesterol, triglycerides, HDL, and LDL.
HDL and LDL. Which is good and which is bad?
LDL is bad. Think L should be Low.
HDL is good. Think H healthy, you want it high.
Should lipid profile be collected fasting or non fasting?
9-12 hour fasting.
What is cholesterol used for?
Structural component of cell wall membranes.
Precursor to steroid hormones and bile acids.
Is the majority of cholesterol dietary or synthesized?
90% is synthesized by the liver.
Goal cholesterol.
<200mg/dl
What are risks of hyperlipidemia?
Cardiovascular diseases such as coronary artery disease and peripheral vascular disease
Does pregnancy increase or decrease cholesterol?
Increase
What are chylomicrons?
A subset of triglycerides that are a marker for dietary fat intake and exogenous triglyceride.
Goal triglycerides
<150 mg/dl
T/F? You are not at risk for coronary artery disease if you have normal LDL, HDL, and cholesterol, but have high triglycerides.
False! Triglyceride elevations alone are an independent risk factor for coronary artery disease.
Goal HDL (high density lipoprotein)
> 60mg/dl
Goal LDL (low density lipoprotein)
It depends on your risk factors, but in general <100 is good. Lower for patients at higher risk for coronary artery disease.
How to calculate LDL.
LDL=cholesterol-HDL-(triglycerides/5). ONLY WORKS IF TRIGLYCERIDES <400mg/dl.
What are the ACA guidelines for lipid management?
ACA focuses on lifestyle modifications (smoking cessation, healthy weight, exercise and healthy diet) and statin usage in higher risk groups.
What class of medications are statins?
HMG CoA reductase inhibitors.
What time of day should statins be taken?
Best taken at night. Much of lipid synthesis is done at night.
What are the 4 statin benefit groups according to the ACA?
- Pt’s with ASCVD
- Anyone with LDL >190md/dl
- Pt’s 40-75 years with DM and LDL between 70-189 mg/dl
- Pt 40-75 with LDL 70-189 and estimated 10 year risk of ASCVD >7.5%
What is a CRP used for in cardiology?
Predicts cardiac risk factors. CRP is an inflammatory marker and atherosclerotic plaques contain inflammatory cells.
CRP is NONSPECIFIC, so its used in conjunction with LDL.
What labs can be used to detect and MI?
CK/CK-MB
Troponin
LDH
Myoglobin
What types of troponin are specific for MI’s?
Troponin I and Troponin T
In relation to an MI, when does troponin I and T elevate, peak and return to normal?
elevation: 3-12 hours
Peak: 12 hours for Tn I, 2 days for Tn T
Return to normal: 5 days
What types of CK are there?
CK-MM: skeletal muscle
CK-MB: cardiac muscle
CK-BB: brain tissue
In relation to an MI, when does a CK-MB elevate, peak, and return to normal?
Elevation: 3-12 hours
Peak: 24 hours
Return to normal: 2-3 days
What is an MB index?
Percentage of CK-MB relative to total CK. Index >2 suggests myocardial source.
In relation to an MI, when does myoglobin elevate, peak, and return to normal?
elevation: 1-4 hours first marker to go up after an MI
Peak: 6-7 hours
Return to normal: 24 hours
What can interfere with a myoglobin test?
Skeletal muscle injury, trauma, and renal failure.
In relation to an MI, when does LDH(lactate dehydrogenase) elevate, peak, and return to normal?
Elevation: 24-48 hours
Peak: 2-3 days
Return to normal: 8-14 days
When is an LDH useful?
When a patient comes in with “My chest pain started 10 days ago”. LDH will still be elevated although other labs may have returned to normal.
What isoenzymes of LDH are found in the heart? What is an LDH flip?
Isoenzymes LDH 1 and LDH 2 are found in the heart.
An LDH flip is when LDH 1 > LDH 2 and is indicative of a cardiac event.
What is BNP and what is its function?
B natiuretic peptide. Function is to oppose the activity of the RAAS.
What does BNP measure?
Measures atrial and ventricular stretch.
What does high BNP indicate?
CHF.
Also increased in MI, HTN, and cor pulonale.
What is a normal BNP?
in general <100pg/dl.
It naturally increases with age and is higher in healthy women in comparison to healthy men.
What medication increases BNP?
Natrecor, which is a CHF treatment.
T/F. A patient can be discharged after 1 negative troponin if his pain started 3 hours ago.
False! it takes time for a troponin to rise, they should have serial troponins every 1-3 hours.
If it started greater than 6 hours ago an MI can be ruled out with a negative troponin
T/F. A troponin should not be drawn as an outpatient.
True. First off, if you suspect an MI they need to go to the ER, but also troponin is time sensitive and needs to be run quickly after being drawn.
What is hemolysis in the setting of blood draws and what lab is one cardiac lab it can effect?
Hemolysis sometimes occurs when a patient is a difficult stick and red blood cells are destroyed in the process of drawing the blood.
It can elevate an LDH.
