Ask The Doctors: September 2015
aortic aneurysm. She didn’t know she had it until she had a chest x-ray for a lung problem. Are most aneurysms found “by accident?” Is it something a doctor should look for routinely, even without symptoms?
The aorta is the largest artery in the body, originating from the heart’s left ventricle, looping around in the chest, and then continuing through to the abdomen until it divides into the left and right iliac arteries. These give off further branches before proceeding to the legs as the femoral arteries. Due to its natural springiness and strength, which derive from specialized intertwining elastic fibers, the aorta is known as an “elastic” artery. Its ability to receive and transmit the force of blood being ejected from the heart allows the aorta to maintain a smooth forward pulse, carrying blood to distant organs. If the aorta enlarges to 1.5 times or more its normal diameter, it is called an “aneurysm.” In the chest, a dilated aorta is referred to as a thoracic aortic aneurysm (TA), while in the abdomen, it is known as an abdominal aortic aneurysm (AAA). Thoracic aneurysms are relatively rare compared to abdominal aneurysms, and are usually asymptomatic. As such, they generally are found incidentally, such as on your friend’s chest x-ray. AAAs, on the other hand, are screened for by ultrasound in men over the age of 65 with any history of smoking.
In most cases, the underlying structural problem leading to ballooning-out of the thoracic aorta is loss of smooth muscle cells and degeneration of elastic fibers. This is not a normal aging process, although age and hypertension can accelerate it. Unless a patient has a family history of TAs, or if they suffer from a connective tissue disorder, there is no indication to screen for TA in an asymptomatic individual. If a cardiac murmur is heard on physical exam, hoarseness is noted, or if the patient describes chest/back discomfort or difficulty swallowing, then further workup with an echocardiogram or CT scan is reasonable. Surgery is usually performed when the thoracic aneurysm reaches 5.5 cm in diameter, or if the rate of expansion is unacceptably high. People with connective tissue disorders or an abnormal aortic valve receive surgery at 5 cm. When aneurysms are not large enough to warrant surgery, beta blockers are used to reduce the stress and strain on the dilated blood vessel.
I recently had two stents put in my heart. How will my doctor know if there is any reblockage in those arteries or other problems, such as infections, in the years ahead? Are there signs I should know about?
Many years ago, cardiologists would sometimes perform a repeat heart catheterization in order to take a “second look” at stents six months or a year after implantation to determine if restenosis—renarrowing inside the stent—had occurred. This type of procedure is no longer performed, both because the patient’s symptoms are more important than how the stents appear, and because the risk of the invasive cardiac procedure exceeds its benefits. Perhaps you experienced a heart attack, or myocardial infarction (MI), as a reason for having stents placed. Or alternatively, prior to stent placement, you may have been feeling chest discomfort, shortness of breath, or one or more other symptoms with exertion which have now resolved. These types of exertional symptoms are the ones for which to keep a lookout.
In-stent restenosis is a gradual process, and as such there is usually time for you to verify a worsening in symptoms and let your doctor know about them. A stress test may be used to help determine whether or not blood flow is being impaired to the area supplied by the stent. Regarding stent infection, this is an extremely rare phenomenon, and is not something you should expend considerable time or energy worrying about.