The Bland-White-Garland syndrome (BWGS) is an extremely rare congenital cardiac abnormality . This syndrome was first mentioned in 1886, but the full
anatomy and clinical symptoms were first described by Bland, White and Garland in 1933 [5,6].
Within this syndrome, the left coronary artery (LCA) has an unexpected anomalous origin from the pulmonary artery instead of the aorta. Blood flow in the coronary system follows the direction of pressure gradient and takes the path of lowest resistance [14,15]. In patients with BWGS, blood flows from the normal origin of the (often enlarged and dilatated) right coronary artery (RCA) through myocardial coronary collateral vessels to the LCA and low-pressure system of the pulmonary artery system [15,25]. After the drop of pulmonary vascular resistance in the first months of life, the majority of the blood drains to the pulmonary arteries, causing a “coronary steal” phenomenon, a left-to-right shunt and ultimately leads to an abnormal left ventricular perfusion . This may lead to myocardial ischaemia and infarction, left ventricular dysfunction, mitral insufficiency and regurgitation, congestive heart failure and finally to sudden cardiac death [35,47].
BWGS occurs between 0.26 % and 0.46 % of patients with congenital heart disease and appears once in 300,000 births [3,22]. It is usually seen as an isolated cardiac abnormality, but in about 5 % of cases, it appears in coexistence with other cardiac abnormalities like patent ductus arteriosus (PDA), atrial septal defect (ASD), ventricular septal defect (VSD) with or without mitral stenosis, tetralogy of Fallot, pulmonary stenosis, coarctation of the aorta or transposition of the great vessels [1,4,8,10,15,34,35,43,45,48]. Symptoms usually become clinically apparent shortly after the neonatal period . Vascular resistance is equal in right (pulmonary artery) and left (aorta) system during foetal period. This condition allows the myocardium supplied by the anomalous artery to remain well perfused. Promotive at this stage of development, there is an identical oxygen content in the pulmonary artery in comparison to the aorta. For this reason, this coronary anomaly is well tolerated in foetal and early neonatal life [4,35,38]. These conditions lead to an antegrade flow in anomalous LCA as well as in normal RCA . In consequence, coronary collateral growth is not especially promoted before birth . When pulmonary arterial pressure decreases physiologically after birth, the antegrade LCA flow diminishes and reverses.
Moreover, the antegrade LCA is filled with deoxygenated mixed venous blood . Subsequent, this coronary steal phenomenon leads to ventricular (anterolateral) myocardial
ischaemia and in further consequence to mitral valve papillary muscle dysfunction [15,35].