What is the success rate of Computed Tomography (CT) coronary angiography?

From the Guidelines

CT coronary angiography is a highly successful non-invasive imaging technique for evaluating coronary artery disease, with a high sensitivity and specificity for detecting significant coronary stenosis, as demonstrated by the most recent study in 2022 1.

Key Considerations for Success

• Patient selection is crucial, with better results in those with low-to-intermediate pretest probability of coronary disease, BMI under 35, and without extensive coronary calcification 1.
• A heart rate below 65 beats per minute is recommended, which may require pre-scan beta-blockers like metoprolol 50-100mg orally 1 hour before the scan or IV metoprolol 5mg increments up to 20mg immediately before imaging.
• Sublingual nitroglycerin 0.4mg should be administered 3-5 minutes before scanning to dilate coronary arteries for better visualization.

Diagnostic Accuracy

• The scan typically achieves 90-95% sensitivity and specificity for detecting significant coronary stenosis when performed on appropriate patients with modern CT scanners (64-slice or higher) 1.
• The high negative predictive value (NPV) of CT coronary angiography can reassure caregivers that providing guideline-directed medical therapy (GDMT) and deferring consideration of revascularization constitute a sensible strategy 1.

Radiation Dose and Safety

• The radiation dose has decreased significantly with newer scanners, now typically 2-5 mSv, comparable to background radiation received over 1-2 years.
• Patients with irregular heart rhythms, inability to hold breath, or previous coronary stents may have reduced image quality 1.

Clinical Implications

• CT coronary angiography has been shown to change treatment among patients with stable chest pain and a high pretest probability of CAD, with increased use of preventive therapy when atherosclerosis is identified and cancellations of preventive and antianginal therapy with normal coronaries 1.
• The use of CT coronary angiography in addition to standard of care has been demonstrated to result in a significantly lower rate of death from coronary heart disease or nonfatal myocardial infarction at 5 years compared with standard of care alone 1.

From the Research

CT Coronary Angiography Success

• The success of CT coronary angiography can be measured by its diagnostic accuracy in detecting coronary artery disease, with studies showing high to very high sensitivity and specificity 2.
• CTCA has been found to be a reliable alternative to invasive coronary angiography (ICA) in low- to intermediate-risk patients, but less effective in high-risk cases 2.
• The use of CTCA can minimize the number of invasive procedures and related consequences, and has been shown to decrease myocardial infarctions over an extended period 2.
• The technique has undergone significant technological improvements over the last two decades, with high accuracy in detecting significant coronary stenosis 3.
• CTCA-derived physiological assessment can be used as a surrogate for intracoronary pressure and velocity wires, enabling decision-making about revascularization solely based on computed tomography 3.

Factors Affecting CT Coronary Angiography Success

• Heart rate is a major factor in selecting the scan mode for CTCA, with beta blockers and nitrates recommended as premedication under certain conditions to improve image quality at low radiation exposure 4.
• Coronary calcifications and body mass index (BMI) are also important factors to consider when selecting the scan mode 4.
• The choice of scan mode depends on heart rate and heart rate variability, such as arrhythmia 4.
• The use of contrast material-enhanced CT coronary angiography has become an established clinical indication for certain scenarios, such as coronary artery anomalies and bypass patency 5.

Clinical Applications of CT Coronary Angiography

• CTCA is recommended in symptomatic patients with a low or intermediate clinical likelihood for coronary artery disease, according to current European Society of Cardiology (ESC) guidelines 4.
• CTCA can be used to exclude coronary artery disease in patients with a low to intermediate clinical likelihood 4.
• The technique can provide a complete assessment of coronary artery disease, including anatomy, functionality, and plaque composition, potentially replacing invasive assessment 3.