Page 133 - Registrar Orientation Manual 2016

Reference:
1257
Effective date:
7 July 2015
Expiry date:
6 July 2018
Page:
16 of 35
Title:
Imaging Guidelines
Type:
Clinical Guideline
Version:
02
Authorising initials:
Referrals need to include the patient’s resting heart rate, suitability for outpatient metoprolol loading (50 mg BD for the day prior to scan and on the morning of the scan) and any contraindication to BB therapy. Radiation can be reduced in patients with steady heart rates <60.
All requests for CTCA will be reviewed by the cardiologists Drs Mark Davis and Madhav Menon. Requests must be legible and include adequate information or they will be declined.
Note that TAVI assessments/protocols are not CT coronary angiograms, so requests are fielded by the radiology department.
Myocardial perfusion scintigraphy is an alternative to exercise testing in patients who cannot exercise, who have LBBB or who have an equivocal exercise test. Radioisotope scanning is also an alternative modality for functional imaging in oncology patients having chemotherapy.
Because of limited capacity all requests for non-oncology patients must be submitted with the name of the Cardiologist or CPU SMO who has made the recommendation or the referral will be returned.
Stress echocardiography is only available on a very limited basis in Waikato and will only be considered when other modalities will not answer the question (e.g. differentiating aortic valve pseudostenosis from stenosis, assessing aetiology of symptoms in hypertrophic cardiomyopathy, assessing functional reserve pre cardiac surgery). Requests are to be discussed with Dr Mark Davis.
Cardiac MRI is available on a limited access and it must be requested by or in consultation with a Cardiologist. MRI will be considered for:
• evaluation of a cardiomyopathic aetiology (usually LVEF<40%), following exclusion of ischaemia and reversible causes, where the answer has not been determined by echocardiography or other modalities
• evaluation of myocardial viability when echocardiography does not provide adequate information and the outcome will dictate major management decisions
• assessment for aetiology of ventricular dysrhythmia following exclusion of ischaemia and reversible causes
• assessment of aetiology of elevated troponin post normal angiography
• assessment for possible myocarditis/ pericarditis if echocardiography not diagnostic
• assessment of simple congenital heart disease / shunts (complex congenital disease MRI in adults is performed in Auckland following discussion with Dr TV Liew)
• family screening for appropriate genetically inherited heart disease conditions (for example arrhythmogenic right ventricular cardiomyopathy) or following suggestive screening echocardiography (e.g. hypertrophic cardiomyopathy) following discussion with the Waikato Cardiac Inherited Diseases Group (1st contact Mandy Graham, Dr Martin Stiles)
• assessment of right or left ventricular function or left ventricular mass when other modalities do not suffice and the outcome will dictate major management decisions
• assessment of aortic regurgitation severity when echocardiography does not provide adequate information and the outcome will dictate major management decisions
• assessment of cardiac masses (including ventricular thrombus in the setting of poor ventricular function) where the answer has not been determined by echocardiography or other modalities
• assessment of hypertrophic cardiomyopathy (thought not likely due to aortic stenosis or hypertension, wall thickness not isolated to the septum >15 mm by echocardiography)
Stress cardiac MRI is not currently performed in Waikato.