When is coronary angiography recommended for diagnosing coronary artery disease?

Coronary Angiography for Diagnosing Coronary Artery Disease

Coronary angiography is most strongly recommended when patients have unacceptable ischemic symptoms despite guideline-directed medical therapy and are candidates for revascularization. 1

Class I Indications (Strongest Recommendations)

Proceed directly to invasive coronary angiography in these situations:

• Patients with presumed stable ischemic heart disease (SIHD) who have persistent, unacceptable ischemic symptoms despite optimal medical therapy and who are amenable to coronary revascularization 1

• Patients with very high (>85%) clinical likelihood of obstructive CAD, severe symptoms refractory to medical therapy, angina at low exercise levels, and/or high event risk 1

• Patients with de novo symptoms highly suggestive of obstructive CAD occurring at low exercise levels—proceed directly to angiography after cardiologist assessment 1

• Patients who have survived sudden cardiac death or life-threatening ventricular arrhythmia 1

• Patients with heart failure and angina or significant ischemia (unless not eligible for revascularization) 1

Class IIa Indications (Reasonable to Perform)

Coronary angiography is reasonable in these clinical scenarios:

• Patients with suspected SIHD whose clinical characteristics and noninvasive testing results (excluding stress tests) indicate high likelihood of severe disease, when they are revascularization candidates 1

  • This includes patients with long-standing diabetes with end-organ damage, severe peripheral vascular disease, or previous chest radiation therapy 1

• Patients who cannot undergo diagnostic stress testing, or have indeterminate/nondiagnostic stress tests, when findings will likely result in important therapy changes 1

• Patients with depressed left ventricular function (EF <50%) and moderate-risk noninvasive testing showing demonstrable ischemia 1

• Patients with inconclusive prognostic information after noninvasive testing, or when noninvasive testing is contraindicated or inadequate 1

• Patients with unsatisfactory quality of life due to angina, preserved LV function (EF >50%), and intermediate-risk noninvasive testing 1

• Patients with heart failure and chest pain of uncertain cardiac origin who have not had coronary anatomy evaluation and have no contraindications to revascularization 1

Class IIb Indications (May Be Considered)

Coronary angiography might be considered when:

• Stress test results of acceptable quality do not suggest CAD, but clinical suspicion remains high and findings will likely result in important therapy changes 1
  • This addresses the scenario where Bayes' theorem predicts that high pretest probability patients may still have significant disease despite negative stress testing 1

When NOT to Perform Coronary Angiography (Class III)

Do not perform coronary angiography in these situations:

• Patients who elect not to undergo revascularization or are not candidates due to comorbidities 1

• Patients with preserved LV function (EF >50%) and low-risk noninvasive testing 1

• Patients at low clinical risk who have not undergone noninvasive risk testing 1

• Asymptomatic patients with no evidence of ischemia on noninvasive testing 1

Critical Technical Considerations

When performing invasive coronary angiography:

• Use radial artery access as the preferred approach—this reduces mortality and major bleeding compared to femoral access 1

• Have coronary pressure assessment (FFR/iFR) readily available to evaluate functional severity of intermediate stenoses (40-90% for non-left main, 40-70% for left main) 1

  • FFR ≤0.80 or iFR ≤0.89 indicates hemodynamically significant stenosis 1

• Consider intravascular ultrasound (IVUS) for evaluating intermediate left main stenoses 1

Important Caveats and Limitations

Recognize that coronary angiography has inherent limitations despite being the "gold standard":

• Visual assessment overestimates stenosis severity when ≥50%, with significant interobserver variability 1

• Many stenoses appearing ≥70% by visual assessment are not hemodynamically significant, while some <70% stenoses are functionally significant 1

• Diffusely diseased arteries without normal reference segments may lead to underestimation of lesion severity 1

• Complication rates include 1.5% procedural complications for diagnostic angiography, with 0.1-0.2% composite rate of death, MI, or stroke via radial access 1

Contemporary Context: Role of Non-Invasive Testing

The 2024 ESC guidelines emphasize a structured approach:

• In patients with >5% pretest probability, either coronary CT angiography (CCTA) or functional imaging is recommended as initial testing 1

• CCTA is preferred for ruling out obstructive CAD in patients with low-to-moderate (>5%-50%) pretest probability 1

• Functional imaging is recommended if CCTA shows CAD of uncertain functional significance 1

This algorithmic approach prioritizes non-invasive testing first in most patients, reserving invasive angiography for those with high pretest probability, refractory symptoms, or when non-invasive testing is inadequate or suggests high-risk disease requiring revascularization.