Deck 34: Cardiovascular Disease

Question 1

Which one of the following is considered to be the most specific marker for adverse ventricular remodeling following an acute myocardial infarction?

A) CK-2
B) Troponin
C) Myoglobin
D) Brain natriuretic peptide (BNP)

Answer 1

Brain natriuretic peptide (BNP)

Question 2

In a point-of-care (POC)test for a cardiac biomarker used in the evaluation of an individual with possible acute coronary syndrome,which one of the following is a Laboratory Medicine Practice guideline of the National Academy of Clinical Biochemistry (NACB)?

A) POC testing must be performed with a maximum turnaround time of 24 hours.
B) POC assays should provide quantitative results.
C) Quality control and quality assurance are not required when using POC assays.
D) Laboratories that use qualitative POC biomarker assays should confirm results with a quantitative biomarker test.

Answer 2

POC assays should provide quantitative results.

Question 3

A 55-year-old man is taken to a hospital emergency department by helicopter following a rural automobile accident that occurred approximately 3 hours ago.The man,who is having difficulty speaking to the EMTs,is clutching his chest.Upon the man's arrival,the emergency room physician orders a cardiac marker panel that includes serum CK,CK-2 (CK-MB),troponin,and myoglobin.The CK-2 value was less than 2% of total CK,which was slightly increased; troponin was normal; and the myoglobin was increased 3 times the upper limit of normal.The physician has asked the laboratory to explain the findings.Which of the following represents the lab's explanation?

A) The assays used to determine these results were nonspecific and not sensitive enough to detect the troponin.
B) Trauma caused by the accident with possible crush injury to the chest caused elevated myoglobin with normal troponin and CK-MB.
C) The use of serum as a specimen interfered with troponin and CK-MB immunoassays giving falsely low results.
D) It is expected that in someone who has had a myocardial infarction in the past that all cardiac biomarker values except myoglobin to have returned to normal.

Answer 3

Trauma caused by the accident with possible crush injury to the chest caused elevated myoglobin with normal troponin and CK-MB.

Question 4

What are the laboratory results for CK-MB and cardiac troponin in the following conditions: muscular dystrophy,polymyositis,and extreme physical activity?

A) CK-MB elevated,troponin normal
B) CK-MB elevated,troponin elevated
C) CK-MB normal,troponin elevated
D) CK-MB normal,troponin normal

Question 5

Regarding assessment of congestive heart failure,NT-proBNP can be measured.This protein is:

A) the C-terminal portion of the prepro-hormone natriuretic peptide (BNP).
B) the N-terminal fragment of pro-BNP.
C) an isoenzyme that migrates separately from BNP on an electrophoresis.
D) degraded by circulating proteases to form the final form of BNP.

Question 6

Which one of the following cardiac markers is elevated for the longest period of time after a myocardial infarction?

A) Troponins
B) hs-CRP
C) CK-2 (CK-MB)
D) Myoglobin

Question 7

Why would high-sensitivity C-reactive protein (CRP)be an indicator of a potential myocardial infarction?

A) It is an acute phase reactant plasma protein that rises in response to inflammation and the atherosclerotic process.
B) CRP levels rise in response to decreased ATP generation in the heart.
C) It is a myocardial protein that regulates muscle contraction through interaction with myosin and actin.
D) It is an enzyme found in skeletal muscle and cardiac muscle that is released upon muscle damage.

Question 8

Laboratory measurements for brain natriuretic peptide (BNP)be reported in:

A) millimoles/liter.
B) grams/deciliter.
C) nanograms/liter.
D) picomoles/milliliter.

Question 9

Which one of the following cardiac biomarkers is elevated about 50 times the upper limit of normal at 24 hours after onset of an acute myocardial infarction?

A) Total CK
B) CK-2 (CKMB)
C) Myoglobin
D) Troponin

Question 10

A cardiac marker that increases progressively with increasing severity of disease and is not increased (or decreased)in conditions that mimic congestive heart failure is:

A) troponin I.
B) CK-2.
C) B-type natriuretic peptide.
D) myoglobin.

Question 11

In regard to cardiac anatomy,the myocardium:

A) is the outermost layer of the cardiac wall.
B) is composed of two upper chambers,the right and left atria.
C) contains bundles of striated muscle fibers.
D) is the sac that encloses the heart.

Question 12

The most common laboratory method used to assess brain natriuretic peptides is:

A) HPLC.
B) serum electrophoresis.
C) nephelometry.
D) immunoassay.

Question 13

Which one of the following troponins appears as uncomplexed or free following myocardial injury?

A) Cardiac troponin I
B) Cardiac troponin T
C) Cardiac troponin C
D) Ternary complex of T-I-C

Question 14

The protein in cardiac muscle fibers that regulates contraction is:

A) actin.
B) myosin.
C) B-type natriuretic peptide.
D) troponin.

Question 15

Which one of the following specimen types and collection methods is best for laboratory assessment of brain natriuretic peptide (BNP)in the evaluation of congestive heart failure?

A) Serum in glass blood collection tubes only
B) EDTA-anticoagulated whole blood or plasma in plastic blood collection tubes only
C) Heparinized plasma in any type of blood collection tube
D) Urine in sterile collection container for analysis of BNP metabolites only

Question 16

An ideal cardiac marker should be elevated in the circulation for how long following a cardiac event?

A) At least several days
B) 1 to 2 months
C) 1 to 3 hours
D) 1 to 3 years

Question 17

In the process of atherosclerotic plaque formation,what is the typical precipitating event?

A) Increased concentration of circulating coagulation factors
B) Cellular involvement and clot formation
C) Damage to the endothelium of cardiac blood vessels
D) Release of tissue factor leading to coagulability

Question 18

MATCHING
For each of the cardiac biomarkers,match the biochemical classification.
Protein involved in muscle fiber contraction

A)BNP
B)CK-MB
C)Troponin
D)Myoglobin

Question 19

In your clinical chemistry laboratory,you use an immunoassay to detect blood levels of NT-proBNP.You receive a filled green-top anticoagulant-containing plastic blood collection tube with a request for NT-proBNP.What is your next step?

A) Because this is an incorrect specimen type,contact the physician/nurse immediately and request a serum specimen.
B) Proceed,because this tube contains heparin and provides plasma after centrifugation,which is acceptable for the NT-proBNP assay.
C) Proceed,because this tube will provide serum after centrifugation,which is acceptable for the NT-proBNP assay.
D) Because only whole blood is acceptable,go ahead and run the test on the green-top tube.

Question 20

Chest pain that is associated with a decrease in oxygen supply to the heart muscle but that exhibits no cellular necrosis based on cardiac troponin value and is considered a less severe event is referred to as:

A) angina.
B) acute myocardial infarction.
C) congestive heart failure.
D) thrombolysis.

Question 21

MATCHING
For each of the cardiac biomarkers,match the biochemical classification.
Protein hormone

A)BNP
B)CK-MB
C)Troponin
D)Myoglobin

Question 22

MATCHING
For each of the cardiac biomarkers,match the biochemical classification.
Oxygen-binding protein

A)BNP
B)CK-MB
C)Troponin
D)Myoglobin

Question 23

MATCHING
For each of the cardiac biomarkers,match the biochemical classification.
Enzyme isoform

A)BNP
B)CK-MB
C)Troponin
D)Myoglobin