From the Guidelines
Cardiac CT is as effective as diagnostic catheterization for evaluating stable coronary artery disease, and it is recommended as the preferred initial test in patients with lower ranges of clinical likelihood of CAD. According to the most recent guidelines from the American College of Cardiology/American Heart Association joint committee on clinical practice guidelines 1, coronary computed tomography angiography (CCTA) can visualize and help diagnose the extent and severity of nonobstructive and obstructive CAD, as well as atherosclerotic plaque composition and high-risk features. The study published in the Journal of the American College of Cardiology in 2020 1 also supports the use of CCTA as a first-line strategy in evaluating stable coronary artery disease, as it does not result in more cardiac catheterizations and revascularization.
Some key points to consider when evaluating the effectiveness of cardiac CT include:
- High negative predictive value (95-99%) for ruling out significant coronary artery disease
- Ability to visualize coronary anatomy and diagnose the extent and severity of CAD
- Calculation of fractional flow reserve with CT (FFR-CT) provides an estimation of lesion-specific ischemia
- Low radiation dosimetry, with effective doses for most patients in the 3 to 5 mSv range
- Contraindications, such as severe kidney disease or contrast allergy, should be considered when ordering a CCTA
The American College of Radiology also recommends the use of CCTA in patients with low to intermediate probability of coronary artery disease, as it has superior diagnostic accuracy compared to other examinations and may reduce downstream noninvasive testing 1. In summary, cardiac CT is a valuable tool in the evaluation of coronary artery disease, and its use as a first-line strategy can improve patient outcomes and reduce healthcare costs.
From the Research
Comparison of Cardiac CT and Diagnostic Catheterization
- Cardiac CT has been shown to be effective in diagnosing and risk stratifying patients with suspected coronary artery disease 2, 3, 4.
- A study found that coronary artery calcium scoring had a high negative predictive value (98.2%) for obstructive CAD, making it a useful tool for ruling out the disease 2.
- However, the same study noted that in patients under 45 years of age, the sensitivity of CAC scoring for obstructive CAD was lower (82.3%), suggesting that a full CCTA may be needed for safely ruling out obstructive CAD in this population 2.
- Diagnostic catheterization, on the other hand, has been found to be overused in some cases, with one study showing that approximately one quarter of patients undergoing DC for suspected coronary artery disease were rated as inappropriate for the procedure 5.
- The use of appropriate use criteria for diagnostic catheterization has been shown to improve the identification of patients who would benefit from the procedure 6.
- Cardiac CT has been found to be effective in predicting outcomes in patients with stable angina, with coronary artery calcium score being a strong predictor of major adverse cardiovascular events 4.
Diagnostic Accuracy
- The diagnostic accuracy of cardiac CT and diagnostic catheterization has been compared in several studies, with cardiac CT showing high sensitivity and specificity for detecting coronary artery disease 2, 3, 4.
- However, the accuracy of cardiac CT can be affected by factors such as patient age and the presence of non-calcified plaque 2, 4.
- Diagnostic catheterization, on the other hand, is considered the gold standard for diagnosing coronary artery disease, but it is an invasive procedure with associated risks and costs 5, 6.
Clinical Implications
- The choice between cardiac CT and diagnostic catheterization should be based on individual patient characteristics and clinical presentation 2, 5, 3, 6, 4.
- Cardiac CT may be preferred for patients with low to intermediate risk of coronary artery disease, while diagnostic catheterization may be preferred for patients with high risk or those who require intervention 2, 5, 6.
- Further research is needed to determine the optimal role of cardiac CT and diagnostic catheterization in the diagnosis and management of coronary artery disease 2, 5, 3, 6, 4.