"An aortic aneurysm is a weak spot in the wall of the aorta, the primary artery that carries blood from the heart to the head and extremities. There are three common types of aortic aneurysm. Saccular and fusiform aneurysms are balloonlike swellings of the arterial wall that can occur in the portion of the aorta within the chest or just below the kidney in the abdomen. A dissecting aneurysm is a longitudinal, blood-filled split in the lining of the artery, usually occurring in the aortic arch near the heart. As blood is pumped through the aorta, the weak spot in the elastic arterial wall bulges outward.
The risk is that an aneurysm will eventually rupture, with great bleeding internally and complete collapse of circulation. Sudden severe pain, shock, and loss of consciousness usually occur within seconds, and death is imminent in more than 50 percent of cases, even with emergency surgery. Thus, the goal is to detect and treat an aortic aneurysm before it ruptures. Aortic aneurysms generally affect people over 60 and are more common among men."
As evident by the description above, Luke's condition is very rare because he is not over 60 (he was 13 when he was diagnosed!) - yet another reason to donate to The Luke Pier Foundation because so much still needs to be learned about pediatric cases like Luke's!