ALCAPA
Definition
- Anomalous Left Coronary Artery from the Pulmonary Artery
- Historically known as Bland-White-Garland syndrome.
- Rare congenital anomaly; Left coronary artery (LCA) arises from pulmonary artery (PA) instead of aorta.
- Prevalence: 1 in 300,000 births.
Pathophysiology
| Phase | Hemodynamic Alteration | Clinical Consequence |
|---|---|---|
| Neonatal | High pulmonary vascular resistance (PVR). Antegrade flow from PA to LCA. | Asymptomatic. |
| 1-2 Months | PVR falls. Flow reversal (LCA to PA) causing "Coronary Steal". | Decreased myocardial perfusion. |
| Progression | Chronic subendocardial ischemia, infarction. | Left ventricular (LV) dilation, mitral regurgitation (papillary muscle infarction). |
Clinical Manifestations
Infantile Presentation (Most Common)
- Onset typically second month of life.
- "Infantile angina": Irritability, diaphoresis, pallor during feeds.
- Congestive heart failure: Dyspnea, tachypnea, failure to thrive.
- Untreated mortality: 90% within first year.
Adult/Late Presentation
- Depends on extensive right coronary artery (RCA) to LCA collateralization.
- Asymptomatic, or presents with angina, syncope, ischemic cardiomyopathy, sudden cardiac death.
Diagnostic Evaluation
Electrocardiogram (ECG)
- Anterolateral myocardial infarction pattern.
- Deep, wide Q waves and inverted T waves in leads I, aVL, V5, V6.
- Diminished/absent R waves in mid-precordial leads (V3, V4).
Echocardiography
- Dilated, poorly contractile LV.
- Mitral regurgitation.
- Color Doppler pathognomonic finding: Retrograde flow from LCA into PA.
Confirmatory Imaging
- CT Angiography (CTA), MRI, or invasive coronary angiography (Gold Standard) defines anomalous origin and collateral extent.
Management
Medical Stabilization
- Heart failure therapy (diuretics, ACE inhibitors, beta-blockers) serves only as short-term bridge.
Surgical Repair (Definitive)
- LCA Reimplantation: Direct coronary button transfer to ascending aorta (Procedure of choice).
- Takeuchi Procedure: Intrapulmonary baffle creation connecting aorta to anomalous LCA ostium (utilized if direct translocation impossible).
- CABG: LIMA or vein graft with LCA ostial ligation.
- Prognosis excellent post-repair; LV function typically normalizes completely.