CT coronary angiogram

CT coronary angiogram is very helpful in the early diagnosis of various heart problems, especially atherosclerosis. This technique is effective in identifying the obstructed or blocked arteries in the heart. The reason for blockage can be the plaque accumulation or the calcium or cholesterol deposits. CT coronary angiogram is advised by the doctor to identify the following problems:

• Blocked or narrowed arteries supplying blood to the heart
• Chest pains
• Irregular heart rate or arrhythmias
• Inadequate supply of oxygen and blood to the heart
• Difficulty in breathing
• Dizziness
• Fainting
• Risk of heart attack

A CT coronary angiogram is used when the risk of coronary artery disease is moderate. However, if the risk is high, the doctor suggests a procedure called coronary angiogram, which involves a catheter insertion and contrast or special dye to clearly see the blockages in the arteries.

Coronary angiogram:

In the Coronary angiogram procedure, the area of catheter insertion i.e. near the groin or arm, is washed and disinfected properly. A local anesthesia injection is then administered. A small incision is made at the site, and a small plastic sheath or tube is inserted inside the artery. The catheter is then inserted in the blood vessels, through the tube, and this is then passed into the coronary artery or the heart, very carefully.

A contrast or a special dye is then given through the catheter. While doing this, the patient might have a slight warmth or flushing sensation. In case the pain or uneasiness increases, the patient is advised to inform the doctor. This technique uses X-ray images and a special dye or contrast to carefully see the flow of blood in the heart. The special dye or contrast is seen in the X-ray images and highlights the blood vessels of the heart as it moves inside the body. This makes it easy for the doctor to pinpoint the affected areas of concern e.g. obstructions or blockages.

If needed, the doctor may also perform a balloon angioplasty or stent implantation, during the coronary angiogram test, to open up a blocked artery.  

CT coronary angiograms:

In CT coronary angiograms, there are no catheters used and this is a noninvasive technique. However, there are contrasts or special dyes, that are used to highlight the blocked arteries or the areas of concern in the X-ray images (of the heart) captured. In this procedure, the contrast or dye is administered intravenously.

As there is no catheter insertion done in CT coronary angiogram, the need for improving the flow of blood or treating blocked arteries may need a separate procedure.

There is another procedure similar to CT coronary angiogram, known as coronary calcium scan. It does not use any contrast media, instead, it uses special CT (computed tomography) images to measure the calcium or plaque levels in the narrowed arteries.

During the CT coronary angiograms, the doctor uses an X-ray machine to take images of the patient's heart. This exposes the patient to the radiations coming from the X-ray machine. Although, these radiations are of low in dose, however, still these might cause some issues in some patients. Patients may also have some problems with the use of a contrast medium. Some of the problems, faced by the patients, undergoing the CT coronary angiogram procedure are listed below:

• A flushing/warm feeling
• Nausea
• Vomiting
• Diarrhea
• Lightheadedness
• Confusion
• Constipation
• Itching at the injection site
• Allergic reactions to the contrast or special dye used during a coronary angiogram
• Stroke
• Arrhythmias or irregular heart rate
• Damage to kidney or kidney failure (rare cases) due to the contrast or special dye used
• Infections
• Risk of developing blood clots
• Hypotension

Some experts believe that the X-ray is not a safe procedure as it sends harmful radiations, which can lead to cell mutations in some people and ultimately, cancer. However, during the CT coronary angiogram procedure, in an X ray, the amount of radiations exposed to a person's body is very small to cause any damage to the cells.

The doctor must be informed if a woman is pregnant or suspects to be pregnant. Although, there is a small risk to the unborn baby in an X-ray, still the doctor might suggest going for some other imaging technique as the unborn babies are very sensitive to any kind of radiations.

In order to examine the heart carefully, the doctor may give some medications, like beta blockers, to the patient before the procedure. These medicines slow down the heart rate of the patient for some time. However, the patients might have some side-effects because of these medications. These side effect include wheezing or difficulty in breathing in asthmatic or COPD patients (Coronary Obstructive Pulmonary Disorder).

The doctor discusses the CT coronary angiogram procedure with the patient in detail. Some of the points to be taken into consideration are as mentioned:

Before the procedure:

• Avoid eating anything at least 4 hours before the procedure.
• Drinking water is allowed but avoid taking any caffeinated beverages. As these beverages may increase the heart rate of the patient hence, making it difficult for the doctor to get clear pictures of the heart.
• The patient would be fine after the test and can drive back home easily.
• Remove the jewelry, eyeglasses, any other metal object worn as they cause artifacts or obstructions when the X-ray images are taken.
• Inform the doctor about any medications you are taking. Accordingly, the doctor will advise if the medication is to be stopped for some time.
• The doctor will take a complete medical history and physical examination of the patient before the CT coronary angiogram procedure.
• If a patient is diabetic, it is important to ask the doctor if insulin is to be taken before the procedure or not.
• Inform the doctor about any past allergies or surgeries, if any.
• The vital signs of the patient, i.e. pulse rate, body temperature, blood pressure, oxygen levels or breathing rate, are checked before the coronary angiogram.
• Empty the urinary bladder before the procedure.
• Change into a hospital gown, during the procedure.

During the procedure:

CT coronary angiogram is usually performed in the outpatient facility or the Radiology Department. The patient is asked to lie down on a padded table, which slides into a big, hollow, circular machine (donut-like). Normally the heart is in motion when it beats. In order to examine the heart carefully, the doctor gives some medications like the beta blockers to the patient. These medicines slow down the heart rate of the patient for some time. Nowadays, some CT angiograms do not use any beta blockers to slow down the heart rate.

The heart rate and rhythms of the heart are monitored continuously during the procedure with the help of electrodes attached to the patient’s body. The vital signs are also monitored simultaneously.

The doctor will then clean the area e.g. arm or hand, from where the contrast or special dye is inserted. The dye is administered intravenously, in order to highlight the arteries of the heart and enable the doctor to detect the problem areas carefully. Before inserting the contrast medium, the doctor gives local anesthesia to numb the area.

Usually, the scanning part of the procedure takes approximately 5 seconds, but the entire procedure including the administration of beta-blockers may take around an hour to finish as, the beta blockers take time to act and to slow down the heart rate of the patient. The X-ray machine will then take images of the patient from various angles. The patient is advised not to move during the procedure and to hold the breath at times, in order to get clear images.

After the procedure:

After the procedure, the electrodes are removed from the patient’s body. The patient is asked to change into normal clothes and allowed to go home. There is no need for hospitalization as it is a noninvasive procedure. The patient is capable to drive back home without any help and can also return back to normal activities. The patient is advised to take a lot of water or fluids, in order to flush out the contrast or dye from the body completely.

The report, from the procedure, is usually available soon after the procedure is done. The doctor discusses the results of the CT coronary angiogram with the patient in detail.

CT coronary angiogram is a very useful and effective procedure in the early diagnosis of various heart problems. It assists the doctor to clearly locate the problematic areas. Some of the findings if a report is abnormal, are as follows:

• Obstructions or blockages and any constrictions in the arteries or blood vessels. The doctors can also check the results of the previous coronary bypass surgery.
• Plaque formations or atherosclerosis.
• Reduction in the amount of blood flow through the arteries.
• Reduced flow of blood to the heart and various surrounding blood vessels.
• Any abnormality in the overall condition and structure of the heart e.g. congenital heart diseases.

If the report of the coronary angiogram is normal, it means:

• There is no abnormality detected
• The heart is healthy and fit
• No obstructions or blockages are observed
• The structure of the heart is normal

If there are any abnormalities detected by the doctor, then some suitable treatment plans will be advised for the patient. The doctor may also advise going for balloon angioplasty or stent implantation to open up the blocked arteries.

Some other points to be taken into consideration, after the test are as mentioned below

• The patient is advised not to smoke and take alcohol, as these interfere with the healing process.
• The patient is advised to eat a healthy and nutritious diet
• The patient is advised to keep the weight in control and avoid eating saturated fat food items. The patient is further advised to control the cholesterol levels and other conditions e.g. diabetes and hypertension with the help of regular exercise
• The patient is asked to learn to manage stress effectively.