A 62-year-old woman with a history of diabetes and hypertension presents with dyspnea, fatigue, and ankle swelling for 4 weeks. On examination, she has a blood pressure of 145/92 mmHg, JVP elevation, bibasal crackles, and a laterally displaced apex beat. Echocardiography shows an ejection fraction of 35% with global hypokinesis and no wall motion abnormality. There is no evidence of primary valvular disease. Which investigation is most appropriate to exclude coronary artery disease as the etiology?

Explanation

## Investigating CAD in HFrEF Without Regional Wall Motion Abnormality **Key Point:** In a patient with HFrEF (EF ≤40%) and risk factors for coronary artery disease (diabetes, hypertension), coronary angiography is the gold-standard investigation to definitively exclude or confirm CAD as the etiology, regardless of whether wall motion abnormalities are present on TTE. ## Why Angiography Is Indicated Here **High-Yield:** The absence of a **regional** wall motion abnormality does NOT exclude CAD. Global hypokinesis can occur in: - **Non-ischemic dilated cardiomyopathy** (idiopathic, viral, infiltrative, toxic) - **Ischemic cardiomyopathy with diffuse subendocardial ischemia** (from multivessel CAD or prior diffuse MI) - **Balanced ischemia** (all territories equally affected) In a patient with multiple CAD risk factors (diabetes, hypertension, age >60), the pretest probability of CAD is high. Angiography is the only test that can definitively establish the presence or absence of coronary stenosis and guide revascularization decisions. **Clinical Pearl:** Guidelines recommend coronary angiography in all HFrEF patients with: - Risk factors for CAD (diabetes, hypertension, smoking, dyslipidemia, age) - Angina or anginal equivalent symptoms - Abnormal stress test results - Uncertainty about etiology despite non-invasive testing ## Comparison of Non-Invasive Stress Tests | Test | Sensitivity | Specificity | Limitations in HFrEF | |---|---|---|---| | **Exercise treadmill** | 60–70% | 70–80% | Poor exercise tolerance; baseline ECG abnormalities; cannot reach target HR | | **Dobutamine stress echo** | 80–85% | 84–86% | Arrhythmias; hypotension; inotrope-induced demand ischemia may not reflect true CAD | | **Myocardial perfusion (SPECT)** | 85–90% | 70–75% | Attenuation artifact; false positives; cannot assess viability well in severe LV dysfunction | | **Coronary angiography** | 95–99% | 99–100% | Invasive; contrast nephropathy risk; gold standard | **Mnemonic: ANGIO-GOLD** — **A**natomic definition, **N**o false negatives, **G**old standard, **I**schemic vs. non-ischemic, **O**utcomes guide revascularization.