SCAD is an uncommon but potentially dangerous cause for heart attacks in young patients and especially young women (less than 50 years of age). Most heart attacks occur because of a blockage in the lumen of a coronary artery. This is usually because of a build-up of atherosclerotic plaque over a number of years and this is why heart attacks are more common in the elderly.
In SCAD, however, the problem is in the wall of the coronary artery. For some reason, bleeding occurs within the wall (in the absence of any precipitating trauma) and the layers of the wall become separated to accommodate the bleeding.
This, in turn, has the effect of reducing the size of the lumen or even squeezing the lumen shut thereby causing a blockage and thereby leading to a heart attack. If the amount of heart muscle deprived of blood is large, then the resulting heart attack can even lead to heart failure, dangerous heart rhythm disturbances or even sudden death.
Who gets it? Typically, it affects women below the age of 50 years of age. Women outnumber men by a ratio of 9:1 SCAD is considered a rare cause of heart attacks. It probably is responsible for about 4% of all heart attacks. In women aged 50 or less it probably accounts for 25-35% of all heart attacks. The proportion is even higher in pregnant women.