1. What is Angiography?
Angiography is a medical imaging technique that is used to visualize the inside of arteries, also called the lumen of blood vessels. Angiography is used to see organs of the body, with particular interest in the arteries, veins and the heart chambers. This is traditionally done by injecting a radio-opaque contrast agent into the blood vessel and doing imaging using X-ray based techniques such as fluoroscopy.
The word itself comes from the Greek words angeion which means "vessel", and graphein which means "to write" or "record". The film or image of the blood vessels is called an angiograph, or more commonly, an angiogram.
2. Why is an angiography done ?
Angiography is done to detect problems with blood vessels that affect blood flow. Examples of such problems include • A tear in a blood vessel (which can cause blockage or internal bleeding), aneurysms (which are weaknesses in the blood vessel wall), and narrowed areas.
• Look for changes in the blood vessels of injured or damaged area.
• Show the pattern of blood flow. This can not only help show how much the blockage has progressed but also guides treatment.
• Show the condition, number, and location of arteries
• Look for a source of bleeding
• Prepare for surgery/interventional procedure on diseased blood vessels Check how bad atherosclerosis is in the coronary arteries.
3. How is angiography done?
In angiography, one of the most widely used approaches to access to the blood vessels is gained through the femoral artery, to look at the left side of the heart and at the arterial system; or the jugular or femoral vein, to look at the right side of the heart and at the venous system. It is by using a system of guide wires and catheters that a type of contrast agent is added to the blood to make it visible on the x-ray images.
The X-ray images taken may either be still images, displayed on an image intensifier or film, or motion images. For all structures except the heart, the images are usually taken using a technique called digital subtraction angiography or DSA. Images in this case are usually taken at 2 - 3 frames per second, which allows the interventional cardiologist to evaluate the flow of the blood through a vessel or vessels. This technique "subtracts" the bones and other organs so only the vessels filled with contrast agent can be seen. The heart images are taken at 15-30 frames per second, not using a subtraction technique. Because DSA requires the patient to remain motionless, it cannot be used on the heart. Both these techniques enable the interventional cardiologist to see the blockage or stenosis or narrowings inside the vessel which may be inhibiting the flow of blood and causing pain.
4. Who needs angiography?
Coronary angiography is done if a patient experiences any of the following:
• Angina. This is unexplained pain or pressure in your chest. A patient may feel it in their shoulders, arms, neck, jaw, or back. The pain may even feel like indigestion. However one needs to be careful to distinguish it from normal indigestion.
• Survived a sudden cardiac arrest (SCA). This is a condition in which a patient’s heart suddenly and unexpectedly stops beating.
• Abnormal results from tests such as an EKG (electrocardiogram), exercise stress test, or other test. Coronary angiography also might be done on an emergency basis, such as during a heart attack. If angiography shows blockages in your coronary arteries, the physician may do a procedure called angioplasty.
5. How do I prepare myself before a coronary angiography?
Most hospitals follow a set routine. Before you come to hospital, your physician will ask you to get few tests done that will help him take better decisions about you. These may include blood tests, an electrocardiogram (ECG),an exercise test and a chest X-ray.
You may be admitted to hospital the night before your coronary angiogram, but most people are admitted the same morning. In most hospitals, people are admitted and discharged from hospital on the same day. You may be asked not to have anything to eat or drink for four to six hours prior to the procedure.
When you are admitted to hospital, your physician will explain the coronary angiography procedure to you, give you a brief physical examination, and answer any questions that you or your family may have. You will be asked to sign a form consenting to the test. You will also be asked to remove any jewellery that you are wearing and to put on a hospital gown. You will then be shaved in the area where the catheter will be inserted. Sometimes you will be given a sedative about an hour before the test to help you to relax. However, you will be awake throughout the procedure As a general rule the below mentioned points should be remembered. However we once again suggest that you talk to your physician in detail about it.
• Any medicines that you're taking should be informed to the physician and necessary discussion should be taken whether you should stop taking them before the test.
• If you have any other condition or diseases that may require taking extra steps during or after the test to avoid complications, then you should discuss this in depth with your physician. Eg: diabetes and kidney disease. Your physician will tell you exactly how the procedure will be done and what precautions to take care before as well as after the procedure. For example, you may be recommended coronary angioplasty if the angiography shows a blocked artery.
6. What to expect during angiography?
During coronary angiography, a patient is kept on his back and kept awake. This allows the patient to follow the physician’s instructions during the test. The patient would be given local anesthesia before the procedure begins. The physician will numb the area on the arm, groin (upper thigh), or neck where he wants the procedure to start. A tube like structure called catheter will then be entered through your blood vessel. Then the physician will use a needle to make a small hole into the blood vessel. The catheter will be inserted through this hole to the heart. The catheter is normally used as a conduit/passage to take other material towards the heart.
Once the physician threads the catheter through the vessel and into the coronary arteries, Special x-ray movies of the lumen of the artery is then taken to help the physician see where to place the tip of the catheter. Once the catheter is properly placed, the physician will inject a special type of dye into the tube. The dye will flow through your coronary arteries, making them visible on an x ray. This x ray is called an angiogram. If the angiogram reveals blocked arteries, the physician may use coronary angioplasty to restore blood flow to your heart.
7. What to expect after coronary angiography?
After coronary angiography procedure is done, the patient is moved to a special area called the Intensive Care Unit in the hospital that is constantly manned by physicians and nurses. It is here that the patient is carefully observed for several hours or overnight. During this time, the patient is asked to limit his/her movement to avoid bleeding from the site where the catheter was inserted. The nurses check heart rate and blood pressure regularly. They’ll also watch for any bleeding at the catheter insertion site.
The patient may develop a small bruise on your arm, groin (upper thigh), or neck at the catheter insertion site. It is advised to talk to your physician if any such thing is observed. At times, Unusual pain, swelling, redness, or other signs of infection at or near the catheter insertion site may be seen. Again it is advisable to let your physician know about this.
Post procedure certain activities should be avoided such as heavy lifting, for a short time after the test.
8. What are the complications associated with angiography?
Coronary angiographies are very common and major complications associated with angiographies are rare. These include cardiac arrhythmias, kidney damage, blood clots (which can cause heart attack or stroke), hypotension and pericardial effusion. Minor complications can include bleeding or bruising at the site where the contrast is injected, blood vessel damage on the route to the heart from the catheter (rare) and allergic reaction to the contrast. However these are not very common.