Coronary angiography

 A coronary angiogram (or arteriogram) is an x-ray of the arteries located on the surface of the heart (the coronary arteries). It helps the physician to see if any of those arteries are blocked, usually by fatty plaque. If so, the patient may be diagnosed with coronary artery disease (CAD).

A coronary angiogram is often conducted along with other catheter-based tests as part of cardiac catheterization, which also includes measuring blood pressure, taking samples for blood tests, and a left ventriculogram.

During an angiogram, the physician injects a special dye (contrast medium) into the coronary arteries. To do that, the physician inserts a thin tube (catheter) through a blood vessel, usually in the upper thigh, and guides it all the way up to the heart. Once the catheter is in place, the physician can inject the dye through the catheter and into the coronary arteries. Then the x-ray can be taken.

Although the physician typically numbs the area where he or she inserts the catheter, the patient is awake for the entire procedure. The patient receives a mild sedative before the procedure and does not ordinarily feel the movement of the catheter within the blood vessels.
Depending on what the angiogram shows, the physician may recommend treatments such as medication, a catheter-based procedure (e.g., balloon angioplasty, coronary stenting) or surgery (e.g., bypass surgery).

About coronary angiograms

A coronary angiogram (or arteriogram) is one of the most accurate tests in the diagnosis of coronary artery disease (CAD), and in the US, over a million of them are done each year. The angiogram is used to pinpoint the location and severity of CAD. For example, it could reveal blockage in an artery due to either a build-up of plaque or abnormalities in the wall of the heart.

An angiogram is a relatively safe, though minimally invasive, test. The test may be administered if CAD is suspected because of symptoms such as:

  • Certain types of chest pain/pressure/discomfort called angina (especially if the patient has a history of heart attack)
  • Shortness of breath (dyspnea)
  • Strong, fast, “galloping” heartbeat (palpitations)
  • Dizziness

Before the day of the coronary angiogram, patients should discuss their medical history with the physician and inform him or her of any medications currently being taken. Certain medications may need to be stopped or reduced. It is also recommended that patients with diabetes consult with a physician regarding food and insulin intake, because people are generally ordered not to eat or drink anything after midnight before the test. Individuals should talk with their physician if they have a blood-clotting disorder or an allergic reaction to any of the following:

  • Iodine
  • Shellfish (e.g., crab or shrimp)
  • Strawberries

On the day of the procedure, the patient will be admitted to the hospital. A nurse or physician will explain what is going to happen, and the patient is encouraged to ask any questions that he or she may have.

During the coronary angiogram

The procedure will begin with the physician inserting an intravenous (I.V.) line into the patient’s arm. The I.V. allows the physician to give the patient a sedative and other necessary medications during the procedure. Small devices (electrodes) will be taped to the patient’s body, which allow the physician to monitor the heart rate.

The physician usually uses the groin/upper thigh area as the place to insert the catheter on its way to the heart, but some physicians may choose to begin at the arm or wrist. Whichever area is chosen will then be cleaned, shaved and numbed (with a local anesthetic). The catheter is then fed through the artery in that area (e.g., the femoral artery in the groin/upper thigh) and up into the heart. There may be some minor discomfort during this period.
When the catheter reaches the target area, the dye is injected through the catheter and into a coronary artery. This is the dye that will allow the physician to clearly see the coronary arteries on the angiogram. The patient may feel hot and flushed for about 10 seconds as the dye is administered. Patients may also be asked by the physician to take certain actions (such as coughing or deep breaths) to help the dye travel through the coronary arteries. During this time, either still or moving angiograms are taken to record the test results.

The dye is easily visible to the physician monitoring the angiogram images. A “shadow” cast by the dye will show blockages of the arteries and abnormal motions of the heart walls. In the case of diseased arteries, for example, arterial walls may appear to be abnormally narrow or irregularly shaped.
Once the angiograms have been taken, the catheter is removed from the body and the hole is sealed with pressure placed on the point of catheter entry. The entire process of taking angiograms lasts approximately 20 to 30 minutes, or a total of 1.5 hours from pre-procedural preparation to the removal of the catheter.

Potential risks with coronary angiograms

While there are some risks involved in any invasive or minimally invasive procedure, coronary angiograms are widely used and complications are low, occurring in less than three percent of patients. These potential complications include:

  • Bleeding in the area of the catheter insertion
  • Abnormal heart rhythms arrhythmias
  • Infection
  • Allergic reaction to the dye
  • Damage to the arteries
  • Heart attack
  • Stroke
  • Air embolism (when air gets into the bloodstream, where it could cause damage)
  • Death

The risk of complications is greater if people are over the age of 70, or have conditions such as diabetes, hardening of the arteries (atherosclerosis), kidney failure or carotid artery disease.