What are the most life-threatening variants of anomalous coronary arteries? 
The most life-threatening variants involve anomalous origin of the left main coronary artery from the right sinus of Valsalva or of the right coronary artery from the left sinus of Valsalva, after which the anomalous artery travels to its normal area of perfusion between the ascending aorta and the main pulmonary artery.