For more than 20 years, stress testing has been the standard of care for the diagnosis of coronary artery disease (CAD or "atherosclerosis").  CAD is the result of accumulation of plaque, which can be composed of fat, fiber, cells, and calcium, in the coronary arteries (blood vessels of the heart). This accumulation of plaque can make the arteries narrow, limiting the amount of blood and oxygen that they heart needs to function normally. Although stress testing identifies most patients with a severe blockage (narrowing) in their coronary arteries, 15-20% of patients will have a falsely negative or inconclusive test result.  Moreover, more than 2/3 of patients who have significant plaque, but no significant blockage, will have a normal exam.  In fact, a majority of patients whose risk of heart attack is higher than normal will have a negative examination.
 
Recently, a new test, known as CT coronary angiography (Coronary CTA), has been developed.  This examination utilizes the most advanced CT scanners to produce pictures of the coronary arteries which are very similar to those produced by a traditional heart catheterization ("heart cath").  More than 50 scientific articles have demonstrated the accuracy of this imaging method in the last four years.  Many doctors, however, remain unaware that this examination is now available in the Triangle or don’t know when it should be used.   Some of the most commonly asked questions about this procedure that we receive from our colleagues:

Is CT scanning accurate?

YES.  A negative CT angiogram excludes significant coronary artery disease with much higher accuracy than stress testing.  A completely normal study can accurately exclude disease in >98% of cases.

Who should be considered for this test?  

1. Patients who have angina-like symptoms (chest pain or shortness of breath), but who are otherwise considered to be low or intermediate risk for disease. A negative CT scan is more accurate and more reassuring than a negative stress test.
2. Patients who have equivocal or non-diagnostic stress test results.   Since CT scanning can accurately exclude significant disease, this helps to avoid unneeded heart catheterizations.  CT scanning is non-invasive, and can cost less than 10% of a traditional heart catheterization.
3. Patients being evaluated for anomalous coronary artery.  CT is the best single test to evaluate this condition, often providing even more information than a traditional heart catheterization.

Who should not be considered for this test?

The examination requires administration of medicines, IV x-ray contrast, and radiation exposure.  Although the risks associated with these agents are not great, they should not be considered trivial.  For this reason, this examination is not recommended for patients who are asymptomatic (coronary calcium scoring is more appropriate for screening).  

Is this examination covered by insurance?

YES.  Most insurance carriers cover CT coronary angiography, and coverage is quickly gaining wide acceptance as this test becomes more common around the country.  Although Medicare covers this examination in several states, this is not always true in North Carolina.  If you have questions about your coverage, we can assist you in clarifying your level of coverage and help with precertification if it is needed.

I have been scheduled for CT coronary angiography.  What do I need to know?  What should I expect?

PRETEST INSTRUCTIONS

1. No caffeine for 24 hrs prior to the exam
2. No food for 4 hours prior to exam
3. Take all prescribed medications on time, as usual, with water only
4. Bring a listing of all medications to your examination
5. Be sure to let staff know of any allergies or if you suffer from asthma.

You must arrive approximately 1 hour prior to your exam because medications are typically given to slow the heart rate (metoprolol – "a beta blocker") and to dilate the coronary vessels (nitroglycerin).  These are usually very well tolerated.  The most common side effects are drowsiness and headache.
 
During the scan, x-ray contrast material will be injected into an arm vein IV.  The contrast injection often causes a transient warm sensation lasting less than one minute.  Nausea is an occasional side effect.
 
The scan is performed in a single breath hold lasting less than 20 seconds.  Typically, patients are discharged immediately following their examination.
 
Computer post processing by the radiologist after the examination usually requires 30-60 minutes.  This delay usually precludes our ability to provide immediate results, but a complete written report detailing your exam results will be available to your doctor within 24 hours.

The information above represents a summary brief of more detailed Coronary CTA information that can be found HERE.