Monday, 30 November 2009

Anomalous Left Coronary Artery arising from Pulmonary Artery (ALCAPA)

Anomalous Left Coronary Artery arising from Pulmonary Artery (ALCAPA)

Anomalous left coronary artery from pulmonary artery (ALCAPA) is a rare congenital cardiac malformation. It presents predominantly in infancy with features of myocardial ischaemia or cardiac failure and may be mistaken for common paediatric conditions such as colic, reflux or bronchiolitis. With early surgical correction the prognosis is good...

Some key learning points about (ALCAPA):

  • The anomaly is also called Bland-White-Garland syndrome and is a rare but serious congenital anomaly, accounting for approximately 0.25-0.5% of all congenital heart disease.

  • ALCAPA is dramatically improved as a result of both early diagnosis using echocardiography with color flow mapping and improvements in surgical techniques, including myocardial preservation.

  • ALCAPA is usually an isolated cardiac anomaly but, in rare incidences, has been described with Patent ductus arteriosus, Tetralogy of fallot, Coarctation of the aorta, and Ventricular Septal Defect (VSD).

  • The left ventricular myocardium is being perfused by relatively desaturated blood under low pressure, leading to myocardial ischemia, during periods of increased myocardial demands, such as when the infant is feeding and crying. Further increases in myocardial oxygen consumption can lead to infarction of the anterolateral left ventricular free wall. This often causes mitral valve papillary muscle dysfunction and variable degrees of mitral insufficiency. As a result, left ventricular myocardium remains underperfused. Consequently, the combination of left ventricular dysfunction and significant mitral valve insufficiency leads to congestive heart failure (CHF).

  • ALCAPA is not considered an inheritable congenital cardiac defect. No risk factors for the occurrence of ALCAPA in any individual family are known, and ALCAPA is not associated with any syndromes or noncardiac conditions.

  • Left untreated, the mortality rate in the first year of life is 90% secondary to myocardial ischemia or infarction and mitral valve insufficiency leading to CHF. Sudden death may occur because of inadequate collateral circulation between the left and right coronary artery systems.

  • Tachypnea, poor feeding, irritability, diaphoresis) in the young infant. Inadequate myocardial perfusion likely causes significant chest pain and these symptoms of myocardial ischemia may be misinterpreted as routine infantile colic.

  • Children outgrow these symptoms and gradually become asymptomatic, although periodic dyspnea, angina pectoris, syncope, or sudden death may still occur in adulthood.

  • Approximately 85% of patients present with clinical symptoms of CHF within the first 1-2 months of life. In unusual cases, the clinical presentation with symptoms of myocardial ischemia may be delayed into early childhood. Rarely, a patient may stabilize following infarction and present with mitral valve regurgitation later in childhood or even adulthood.