Download Modalities of Cardiac Stress Test

Modalities of Cardiac
Stress Test
Tiffany T. Nguyen MD
April 2014
Objectives

To understand the indications and
contraindications for stress testing.

To learn the different modalities of cardiac
stress test.

To effectively select the optimal cardiac
stress test for each patient.
Indications
Who to stress?










Symptoms suggesting angina.
Acute chest pain
Recent ACS after 3 months of conservative therapy
Known CHD and change in clinical status.
Prior coronary revascularization.
Valvular heart disease.
New heart failure or cardiomyopathy.
Chronic left ventricular dysfunction and CHD who are candidates
for revascularization.
Selected arrhythmias
Undergoing non-urgent non-cardiac surgery.
Contraindications
Who NOT to stress?








Unstable angina
Acute myocardial infarction
Arrhythmia with hemodynamic instability
Aortic dissection
Symptomatic aortic stenosis
Symptomatic severe heart failure
Pulmonary embolism
Myocarditis, Pericarditis
Pre-Test Probability
ACC/AHA 2012 Guidelines
Low probability - <10% - no further testing, except for prognostic information.
Intermediate probability - 10-90% - non-invasive testing for diagnosis (exercise ECG as
first modality).
High probability - >90% - non invasive testing for prognosis/management prior to
cardiac cath.
Age
Nonanginal pain
Atypical angina
Typical angina
Men
Women
Men
Women
Men
Women
30-39
4%
2%
34%
12%
76%
26%
40-49
13%
3%
51%
22%
87%
55%
50-59
20%
7%
65%
31%
93%
73%
60-69
27%
14%
72%
51%
94%
86%
Two Components

Each cardiac imaging modality has two
components:

Stressing agent: treadmill, dobutamine, or
adenosine

Imaging agent: EKG, echo, or radionuclide tracer
(thallium or technetium)
Stressing Agents
Stressor
Pro
Con
Treadmill
Physiologic, simple,
less expensive, good
for patient who can
walk
Dobutamine
No exercise needed
Caution in patients with
arrhythmias
Adenosine or
dipyridamole (used with
nuclear)
No exercise needed;
uncomfortable
sensation of “heart
stoppage”
Adenosine may induce
bronchospasm – caution in
COPD and asthma!
Imaging Agents
Stressor
Pro
Con
EKG
Simple, less
expensive
Less information. May not be
able to localize the lesion. Can
not use if there are baseline
EKG abnormalities i.e. LBBB
with ST changes
Echocardiogram
Good if patient has
pre-existing EKG
abnormalities. More
info than EKG. Less
expensive than
nuclear.
Operator dependent to some
extent. May have poor windows
due to body habitus. Preexisting wall motion
abnormalities may make
interpretation more challenging.
Thallium or technetium
Localizes ischemia
and infarcted tissue.
Expensive
Finally …


What is a “MIBI?” What is a “Lexiscan?”
Both are adenosine nuclear stress tests

MIBI: the technetium molecule is attached to
sestamibi molecule. The combined sestamibiTechnitium-99 molecule is aka “cardiolite”

Lexiscan: uses a derivative of adenosine called
regadenosine, which has 2-3 minute half-life
instead of 30sec, so is easier to work with.
Sensitivity and Specificity
Exercise EKG
Sensitivity
68%
Specificity
77%
Stress Echo
76%
88%
Nuclear Imaging
79-92%
73-88%
Selecting Modalities
Indication
Diagnosis or Prognosis
Localize Ischemia
Exercise?
Exercise?
no
no
yes
Pharmacologic test
with Imaging
Normal EKG
Not on Digoxin
No prior revascularization
yes
Exercise EKG
no
Exercise Imaging
yes
Case Question
A 60yo man is evaluated for chest pain of 4 months’ duration. He
describes the pain as sharp, located in the left chest, with no
radiation or associated symptoms, that occurred with walking one to
two blocks and resolves with rest. Occasionally, the pain improves
with continued walking or occurs during the evening hours. He has
hypertension. Family history does not include cardiovascular
disease in any first-degree relatives. His only medication is
amlodipine.
On physical examination, he is afebrile, blood pressure is 130/80mHg,
pulse rate is 72/min, and respiration rate is 12/min. BMI is 28. No
carotid bruits are present, and a normal S1 and S2 with no murmurs
are heard. Lung fields are clear, and distal pulses are normal. EKG
showed normal sinus rhythm.
Case Question
Which of the following is the most
appropriate diagnostic test to perform next?

a.
b.
c.
d.
Adenosine nuclear perfusion stress test.
Coronary angiography
Echocardiography
Exercise treadmill
Take Home Points

Stress testing is indicated for patients with
intermediate pre-test probability

Each stress test has two components: an
imaging modality and stress modality

When determining which stress test to order,
keep in mind their ability to exercise and
whether any contraindications are present