What is the indication for a CT (Computed Tomography) angiogram of the heart with contrast?

Indications for CT Angiography of the Heart with Contrast

CT angiography of the heart with contrast is primarily appropriate for patients with low to intermediate pretest probability of obstructive coronary artery disease (CAD), particularly in symptomatic patients without known heart disease. 1

Primary Indications

• Symptomatic patients with suspected CAD:

  • Low to intermediate pretest probability of obstructive CAD 1
  • Patients with uninterpretable or equivocal stress test results 1
  • Evaluation when other imaging modalities are inadequate or contraindicated 1

• Structural and functional cardiac evaluation:

  • Assessment of coronary anomalies 1
  • Evaluation of congenital heart disease 1
  • Assessment of right ventricular function 1
  • Evaluation of left ventricular ejection fraction when other imaging techniques are inadequate 1
  • Evaluation of prosthetic heart valves 1

• Preoperative assessment:

  • Patients undergoing heart surgery for noncoronary indications (e.g., valve replacement surgery, atrial septal defect closure) with intermediate pretest CAD risk (appropriate) or low pretest CAD risk (uncertain) 1
  • Prior to electrophysiological procedures for anatomic mapping 1
  • Prior to repeat sternotomy in reoperative cardiac surgery 1

• Post-transplant evaluation:

  • Detection of cardiac allograft vasculopathy in heart transplant patients 1
  • Alternative to invasive coronary angiography in experienced centers 1

Specific Clinical Scenarios

• Heart failure evaluation:

  • Patients with reduced left ventricular ejection fraction with low or intermediate pretest CAD probability 1
  • Evaluation of myocardial viability when other modalities are inadequate or contraindicated 1

• Coronary stent evaluation:

  • Limited to left main stents (appropriate) 1
  • Larger stents (≥3 mm diameter) after longer time periods (≥2 years) (uncertain) 1

Inappropriate Uses

• Screening asymptomatic patients using coronary CT angiography 1
• Repeat CT angiography in asymptomatic patients or patients with stable symptoms with prior test results 1
• Preoperative evaluation for noncardiac surgery 1
• High-probability CAD patients who can exercise with interpretable ECG 1
• Routine clinical use in heart transplant patients (not recommended) 1

Technical Considerations

• Dual-source CT systems provide better image quality in patients with persistently high heart rates 1
• CT coronary angiography offers high negative predictive value to exclude coronary stenosis 1
• Radiation exposure and nephrotoxic contrast concerns should be considered, though contemporary scanner technology allows for decreasing radiation doses 1

Clinical Decision Algorithm

1. For symptomatic patients:

   • Determine pretest probability of CAD
   • If low to intermediate probability → CT angiography appropriate 1
   • If high probability → Consider alternative testing 1

2. For structural evaluation:

   • If evaluating coronary anomalies, congenital heart disease, or cardiac function when other imaging is inadequate → CT angiography appropriate 1

3. For preoperative assessment:

   • If heart surgery for noncoronary indications with intermediate CAD risk → CT angiography appropriate 1
   • If noncardiac surgery → CT angiography inappropriate 1

4. For stent evaluation:

   • If left main stent → CT angiography appropriate 1
   • If other stent location, only consider if ≥3 mm diameter and ≥2 years post-placement 1