Stress testing patients on
oral dipyridamole
Dr Parthi Arumugam
Consultant Nuclear Physician
Nuclear Medicine Centre
Manchester Royal Infirmary
Case history
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71 year old male
Typical angina
Peripheral vascular disease
Risk factors for CAD
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Hypertension
Diabetic
Current Smoker
Raised BMI
Parthi Arumugam
What is the next line of
investigation ?
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Exercise testing
Myocardial perfusion imaging
Dobutamine stress echo
CT Coronary angiogram
Invasive Coronary angiogram
Parthi Arumugam
 Based on NICE guidelines on chest pain of
recent onset 1, this patient has a high pre
test likelihood of CAD so invasive coronary
angiogram should be considered.
 The patient decided to have a functional
test, so based on local availability, MPS was
ordered. CTCA is also a suitable alternative.
 So all responses are potentially correct.
1.NICE clinical guidelines 95
http://www.nice.org.uk/nicemedia/live/12947/47938/47938.pdf
Parthi Arumugam
 He was booked for an Adenosine
Rubidium PET perfusion study.
 He turned up for his appointment
having forgotten to stop oral
Dipyridamole.
Parthi Arumugam
What is the most appropriate stress
modality?
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Exercise
High dose Adenosine
Dobutamine
Dipyridamole
Cancel the test and rebook
Parthi Arumugam
 Either exercise or Dobutamine
stressing could be employed but
there are practical issues when used
in conjunction with Rubidium
imaging.
 Cancelling the test is an option but
would inconvenience the patient.
 IV Dipyridamole was used.
Parthi Arumugam
 IV Dipyridamole is a safe and
efficacious in patients who are on oral
dipyridamole2.
 The protocol was completed without
any significant side effects or
ischaemic symptoms.
2
ASNC guidelines
http://www.asnc.org/imageuploads/ImagingGuidelinesStressProtocols021
109.pdf
Parthi Arumugam
Stress
Rest
Stress
Rest
Stress
Rest
Stress
Rest
Parthi Arumugam
 Scans shows extensive inducible
ischaemia in the inferior, inferolateral
and inferoseptal myocardium
(involving 8/20 segments).
Parthi Arumugam
Absolute Blood Flow Measurement
Parthi Arumugam
 Flow measurement showed global
ischaemia with significantly reduced flow
reserve in the RCA and LCx (normal flow
reserve should be more than 2.0),with
probable steal phenomena – resting flow
more than stress.
 Note there is reduced flow in the LAD
territory where relative perfusion was
‘normal’.
Parthi Arumugam
Coronary Angiogram
 Coronary angiogram showed occluded
RCA, tightly stenosed LCx and
moderate LAD disease, which
correlates with the flow reserve
measurement.
 Patient has been referred for CABG.
Parthi Arumugam
Teaching points
 IV Dipyridamole can be used in
patients on oral dipyridamole.
 Relative perfusion assessment can
underestimate extent of ischaemia in
patients with multivessel disease.
Parthi Arumugam