CT Coronary Angiogram (CTCA)

The CTCA scanner takes multiple images of your heart and coronary arteries by rotating the scanner around you while you lie on the table. The scanning time takes only less than a second, but you will need to lie on the scanner table for up to ten minutes. The CTCA scanner will then reconstruct the images into a 3D picture of your heart, and will be able to analyse if you have any significant narrowing or blockages in your coronary arteries.

CTCA is a non-invasive investigation whereas the conventional coronary angiography is an invasive test which requires hospital admission and involves insertion of tubes (catheters) via a arterial sheath to insert or “engage” the coronary artery, thereby allowing dye (contrast) to be directly injected into the arteries. (see information on coronary angiography). On the contrary, CTCA only involves injection of contrast through an intravenous cannula (plastic needle or drip line). You may still require invasive coronary angiography if there are significant narrowing or blockages in your coronary arteries.

• Your cardiologist will prescribe a heart rate slowing medication to be taken at least one day prior to the scan. Better quality images can be taken if your heart rate is slower, and therefore better identify any significant narrowing and blockages in the coronary arteries • If you have any significant allergies or asthma, your doctor will prescribe a medication to reduce any significant allergic reaction towards the dye (contrast) or to reduce the chance of an asthmatic attack. • You can take all your usual medications if you have any except metformin on the day of the scan. • You will need to fast for 4hours prior to the scan. • Do not take coffee, tea, energy drinks or any other food and drinks containing caffeine for at least 24hrs prior to the scan. • Do not take Cialis, Viagra, Levitra or similar medications for 36hrs prior to the scan.

• You will change into a gown and have your blood pressure and heart rate monitored. You will be assessed by your Cardiologist or Radiologist, and may require additional medication as determined by them. • You will have a cannula inserted in the vein near your elbow and ECG leads placed on your chest. • You will be given GTN (nitrolingual spray) under the tongue just before the start of the scan in order to relax your coronary arteries so as to obtain the best optimal images. This medication may, however, give u a mild headache. • You may required to hold your breath for up to 15seconds and to lie flat for 5-10mins during the scan. Although the scan itself takes only less than a second, the whole process time can take up to 2hrs. • During the injection of contrast, you may notice a warm sensation and a metallic taste. This is normal. • Following the completion of the scan, we will monitor you for a short period of time before discharging you.

There are minimal risks associated with a scan. • Radiation: The CTCA scanner will use the lowest dose of radiation possible to achieve the best optimal images of your heart and coronary arteries. At a lower dose, this amount of radiation is about ¼ of the amount of background radiation that you may receive in a year from natural sources such as cosmic rays. • Contrast reaction: Very rarely people experience an allergic reaction to the contrast. It may manifest as an itchy rash which usually settles down by itself. However, 1 in 250,000 may develop a life-threatening (anaphylactic) reaction. Asthmatic patients may also experience worsening of their asthma shortly after contrast injection. Patients with kidney failure may also experience (usually temporary) worsening of their kidney function. • Contrast leakage: The contrast can very rarely goes into the tissues under your skin and may cause swelling and bruising. This will usually resolves by itself.

• You may have symptoms or signs suggestive of coronary artery disease such as chest pain • Your cardiologist may require to assess your condition following a cardiac procedure. • To assess how your heart rate responses to exercise. • To assess how your blood pressure responds to exercise. • To examine your heart for potential exercise induced heart rhythm abnormalities. • You may have significant risk factors for coronary artery disease such as smoking, high cholesterol or high blood pressure.

• Some heart medications may need to be stopped prior to the investigation. • Please do not smoke or consume alcohol 4 hours prior to the test. • Please avoid food containing caffeine such as chocolate, tea and coffee for 2hours prior to the test. • You are not required to fast, but encouraged to hydrate yourself and have a light meal a few hours prior to the test. Please refrain from heavy exertion at least 2hours prior to this test. • Please wear comfortable clothing and suitable shoes for brisk walking. • You should able to do the test if you can walk easily or walk briskly. If you believe you cannot walk easily in order to participate in the test, do contact us immediately. Your doctor may recommend another more suitable test after a discussion with you.

• The EST will be supervised by your experienced cardiac technologist and your doctor. • You will be asked to perform the exercise test wearing a gown, with electrode stickers on your chest. The electrodes will be attached to the cables linked to the ECG machine. You will also wear a blood pressure cuff around your arm. • You will be asked to perform a graded exercise test. You will be asked to achieve a pre-determined heart rate. The workload will increase every 3 minutes (in speed and incline). • Your blood pressure and heart rate will be monitored during the test, and also after the test during the recovery stage. • If you experience chest pain or shortness of breath, the EST will be terminated immediately if determined by your doctor. • If you have any symptoms or are unable to progress with the test, you must inform us immediately.

Your cardiologist should have assessed you medically and determined that you will benefit from this investigation. It is a safe procedure, but there are a few risks involved: • Shortness of breath • Chest pain • Dizziness • Abnormal heart rhythm that may require a electric shock (DC cardioversion) • Heart attack (rare) • Death as a result (it is extremely rare: <1 in 10,000)