Disruption of the normal cardiac muscle cell integrity resulting in the loss into the blood of intracellular constituents including detectable levels of proteins such as Troponin Creatine kinase ID: 931571
Download Presentation The PPT/PDF document "Cardiac Enzymes Cardiac Injury" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Cardiac Enzymes
Slide2Cardiac Injury
Disruption of the normal cardiac muscle cell integrity resulting in the loss into the blood of intracellular constituents including detectable levels of proteins such as:
Troponin
Creatine
kinase
Myoglobin
Slide3Troponin
Sensitive biomarker of cardiac injury
Preferred serologic test in the diagnostic evaluation of patients suspected of acute MI
Levels rise within 2-3 hours after onset of acute MI - varies up to 4-8 hours
Levels peak around 12-16 hours
Elevations can persist as long as 10-14 days
Slide4Causes of Troponin Elevation
Acute thrombotic MI with obstructive coronary artery disease – most common
Acute myocarditis
Stress cardiomyopathy
Pulmonary embolism
Trauma (CPR, cardioversion, ICD firing)
Troponin can be chronically elevated in end stage renal disease
Slide5Definition of acute myocardial injury
To diagnose MI, evidence of myocardial injury is defined as:
Troponin above the 99
th
percentile upper reference limit for the normal range
Rise or fall of the troponin value should be observed
Slide6Assay Sensitivity
“Sensitive” or “Contemporary” assays have been used for several years
“Highly sensitive” or “High sensitivity” assays are available and preferred
Used in Europe
First approved for use in US in 2017
Slide7CK-MB
There are 3 isoenzymes of
creatine
kinase – MM, MB, BB
There is more of the CK-MB fraction in the heart
Most muscles have more CK per gram than heart tissue so skeletal muscle breakdown can lead to absolute increase in CK-MB in the plasma
Levels rise 4-6 hours after onset of infarction
Not elevated in all patients until about 12 hours
Returns to baseline within 36-48 hours
Slide8CK-MB
The most commonly used test prior to the introduction of troponin - use has diminished
Troponin is preferred due to increased sensitivity and specificity
“It is difficult to find any situation in which CK-MB adds anything other than cost to the clinical utility of cardiac troponin if that marker is used properly.”
Slide9Myoglobin
Heme
protein that is rapidly released from damaged tissue due to its small size
Present in all types of muscle cells and not specific to cardiac injury
Was thought to be a useful adjunct to troponin for early diagnosis of MI
In high sensitivity assays, troponin is elevated before elevations in myoglobin
There is little advantage for the use of myoglobin unless an insensitive assay is used
Increased within the first 2 hours after onset of injury
Peaks 6-8 hours
Returns to baseline 20 -36 hours
Slide10Troponin
CK-MB
Myoglobin
Increase detected
2-3 hours
(or 4-8)
4-6 hours
2 hours
Peak
12-16 hours
12 hours
6-8 hours
Back
to baseline
10-14 days
36-48 hours
20-36 hours
Slide11Alere Triage Cardiac Panel
Clinical Sensitivity
Time
0-6
hrs
6-12
hrs
12-24
>24
hrs
Overall
CK-MB
77.5%
78.1%
79.1%
84.8%
81.2%
Myoglobin
75%
75%
72.1%
73.9%73.9%Troponin65%71.9%93%95.7%85.5%
Clinical Specificity
Time
0-6
hrs
6-12
hrs
12-24
>24
hrs
Overall
CK-MB
91%
86.4%
82.2%
88.7%
87%
Myoglobin
74.2%
81.8%
67.8%
71.8%
73.4%
Troponin
100%
97%
94.4%
90.1%
95.6%
Slide12Chest pain evaluation
Studies have estimated that of OUTPATIENTS with chest pain
1/3 to ½ have musculoskeletal chest pain
10-20% have GI causes
10% have stable angina
5% have respiratory conditions
2-4% have acute myocardial ischemia
Of ED visits for chest pain, acute coronary syndrome accounts for 12-15%
Slide13Goal of evaluation
Rule in ACS in a timely manner to facilitate early intervention for better outcomes
For patients without ACS, not wasting time and resources pursuing the diagnosis of ACS
Slide14Acute Coronary Syndrome
Myocardial Ischemia – Angina symptoms:
Pressure, heaviness, tightness in the center or left chest
Precipitated by exertion, relieved by rest
Radiation to neck, jaw, shoulder
Dyspnea, Nausea and vomiting, diaphoresis,
Presyncope
, Palpitations
ACS (Myocardial infarction, unstable angina)
Angina symptoms at rest, new and unstable angina, progressive symptoms
These patients should be referred urgently to the ED
Slide15Chest Pain Differential
Cardiac
Myocardial ischemia, aortic dissection, heart failure, pericarditis/
myopericarditis
, stress cardiomyopathy, mitral valve disease
Pulmonary
pulmonary embolism, pneumothorax, pneumonia, malignancy, asthma and COPD, pleuritic, sarcoidosis, acute chest syndrome (sickle cell), pulmonary hypertension
Gastrointestinal
GERD, esophageal pain, esophagitis, eosinophilic esophagitis, hiatal hernia, esophageal motility disorder, esophageal rupture, referred pain from abdominal organs
Slide16Musculoskeletal
Isolated musculoskeletal chest pain syndrome (costochondritis or lower rib pain syndromes), rheumatic diseases, rib pain, trauma
Psychiatric
panic attack/disorder, other (somatization, factitious disorder)
Other
Substance-related, herpes zoster, domestic violence
Slide17Evaluation
History and Exam helps to direct further testing
EKG
If normal consider other testing
Based on initial evaluation many patients will not need further testing
If there is a possibility of ACS, troponin should be tested
In certain populations presentation varies and may present with atypical symptoms without chest pain
Women, diabetics, older patients
Slide18Determining risk of ACS
Very low probability of ACS <1-2% reasonably excludes it
Pitfalls: avoid eliminating the possibility of ACS when an alternative diagnosis is possible
Certain populations with increased risk
for missed ACS:
women younger than 55, nonwhite patients, primary complaint of dyspnea, normal EKG
HEART score used in the ED to help assess risk level and determine need for further evaluation
History, EKG, Age, Risk factors, Troponin
0-2 scale for each
Total score 0-3 translates to low risk – 0.9-1.7% risk of adverse cardiac event
Slide19Case A
40
yo
male presents with substernal left chest pain for 2 hours
Sudden onset severe constant pain while sitting at the desk at work
Worse with walking
Short of breath, dizzy
No history of hypertension or heart disease
BP: 136/85, Pulse: 77, SpO2: 97%, Weight: 260
lbs
, Height: 6’4”
Significant discomfort otherwise unremarkable exam
EKG - normal
Slide20Patient was transferred to ED via EMS
Sudden recent onset of pain, classic symptoms
No benefit to testing cardiac enzymes in the clinic
Slide21Case B
51
yo
female presents with 2 day history of right chest pain
Pain is intermittent, sharp, stabbing, deep
Associated with right upper back pain, right shoulder pain, neck “stiffness”
Started in the afternoon and worsened through the day
Occurs at rest and worse when lying flat
Aspirin helped
Denies shortness of breath, nausea, vomiting, diaphoresis, dizziness, syncope
Negative history of CAD
Positive history of type 2 diabetes, hypertension, HDL<40
Slide22BP: 112/67, Pulse: 70, SpO2: 98%, Weight: 238
lbs
, Height: 5’4”
Tenderness to deep palpation of upper abdomen, otherwise unremarkable exam
EKG – NSR, nonspecific T wave changes in V5, V6, II,
avF
compared to previous EKG from 2 years prior
Cardiac enzymes negative
D-dimer negative
GI cocktail given – gave some but not complete relief of pain
Differential diagnosis: acute on chronic GERD vs. esophagitis with referred pain to right chest vs. chronic pain syndrome/fibromyalgia
Slide23Case C
42 year old male presents with chest tightness and shortness of breath for 1 week
Constant, worse after working out at the gym, not as bad sitting at the desk
Episode last night kept him up all night
Feels “golf ball” like lump in the bottom of the lungs in front of the spine for the past month
Associated symptoms include coughing spasms twice, dizziness at the gym, body aches, joint pains
No nausea or vomiting
No history of CAD or asthma
Stressful job, recent travel to Dallas
Slide24BP: 113/72; Pulse: 53; SpO2: 98%, Weight: 187
lbs
Unremarkable exam
EKG: sinus bradycardia, nonspecific ST changes unchanged from prior 4 years ago
Cardiac enzymes negative
D-dimer negative, normal chest
xray
, normal CBC
Differential includes reactive airway/asthma vs. anxiety/panic
Slide25Case D
76
yo
female presents with substernal discomfort, burping, rotten taste in the mouth since yesterday evening
Symptoms started suddenly while eating an orange
Feels like something is stuck in her chest, has had liquids, but hasn’t tried solids since symptoms started
Associated symptoms include nausea
Denies vomiting, shortness of breath, cough, dizziness, diaphoresis
Past medical history positive for GERD (has not taken omeprazole today), type 2 diabetes, hypertension, hyperlipidemia
Slide26BP: 151/77, Pulse: 74, SpO2: 99%; Weight: 185
lbs
; Height: 5’5”
Appears in moderate discomfort, rubbing lower sternal area, frequent burping, mild epigastric tenderness, otherwise normal exam
EKG sinus bradycardia, nonspecific T wave abnormalities
GI cocktail given with complete resolution of discomfort
Differential includes GERD, esophageal spasm, esophageal obstruction, CAD unlikely given history and symptoms
Slide27Case E
26 year old male presents with shortness of breath today while sitting at the computer
Associated symptoms include chest pressure, neck pain, left arm throbbing
Positive history of
Afib
and was on arrhythmic, but stopped it. Takes 2 baby aspirin daily and goes into
afib
about 3 times a week. Does not feel like he is currently in
afib
. Has constant fatigue.
Drank 2 beers last night
Did arms workout 4 days ago
Denies history CAD, asthma
Slide28BP: 142/87, Pulse: 91, SpO2: 98%, Weight: 249
lbs
, Height: 6’2”
Appears in mild discomfort
EKG – NSR, ST elevation probably due to early repolarization
GI cocktail no help
Negative D-dimer
Cardiac enzymes:
CK-MB: 6 (range 1-8)
Myoglobin: >500 (range 0-107)
Troponin: <0.05 (range <0.05)
Sent to ED for further evaluation
Slide29Case F
34
yo
female with 3 episodes of chest pain over the past week lasting 30 minutes and feels like pressure in the left chest
Associated symptoms include shortness of breath, fatigue, weakness
Denies dizziness
Positive history of gastritis
Negative history of CAD
Slide30BP: 137/89, Pulse: 75, SpO2: 100%, Weight: 128
lbs
Moderate epigastric tenderness otherwise normal exam
EKG – NSR, RSR’ in V1 or V2
Cardiac enzymes negative
D-dimer negative, normal CBC, unremarkable chest
xray
Suspect symptoms related to gastritis
Slide31Case G
28
yo
male with intermittent chest tightness for 1 week, worse today
Associated symptoms include lightheadedness, fatigue, occasional upper abdominal pain, left shoulder sore when stretching
Denies shortness of breath, diaphoresis, extremity weakness, heartburn
Has been able to work out all week without symptoms
History of hypertension, undergoing neurology evaluation for an episode of lightheadedness and blurred vision, MRI was normal, MRA was performed but he does not have the results, history of sludge in the gall bladder
Slide32BP: 134/83, Pulse: 84, SpO2: 99%, Weight: 226
lbs
, Height: 6’2”
Left upper back tenderness with spasm otherwise normal exam
EKG – NSR, no ST changes
Cardiac enzymes negative
D-dimer negative, normal chest
xray
, Glucose 112
Differential includes neurologic etiology, musculoskeletal
Slide33Case H
29
yo
female with constant pinching pain in the left chest for 3 days
Associated symptoms include shortness of breath with activity, dizziness yesterday
Denies diaphoresis
Menstrual cycle present for 17 days with heavier flow for 3-4 days. This is not atypical for her.
Medical history positive for hypertension, PCOS
No history of CAD
Slide34BP: 138/83, Pulse: 104, SpO2: 98%, Weight: 273
lbs
, Height: 5’6”
Exam unremarkable
EKG – NSR, no ST changes
Cardiac enzymes negative
D-dimer negative, normal CBC, normal chest
xray