Although none of the editors of Insidesurgery.com are participating in her care, we have noted with interest today’s announcement that former First Lady Barbara Bush has undergone heart surgery at the Houston’s famed Methodist Hospital. The Associated Press is reporting that she underwent surgery for a “hardened” aortic valve and that she was expected to remain in the hospital for 7-10 days. There are approximately 50,000 “open” aortic valve replacements done every year in the United States.
Mrs. Bush undoubtedly had a condition called aortic sclerosis, a serious and and, if not corrected, life-threatening calcification of the aortic valves leading from the left ventricle of her heart to the the aorta, the main artery that carries blood to the rest of the body. In this condition, calcium deposits build up on the three leaflets of the valve and stiffen the valvular tissue and prevent the leaflets from opening normally. One way to describe aortic stenosis is that the valves “rust shut.”
The causes of aortic stenosis are unknown. Patients with obesity, smoking, diabetes, and atherosclerosis are at an increased risk of developing it. In addition, patients who are born with only two leaflets in their aortic valve have an increased risk of developing aortic stenosis in their 40’s and 50’s.
The development of aortic stenosis causes a classic clustering of symptoms in patients due to the difficulty the pumping heart has to move blood past the obstruction posed by the non-opening valve leaflets. These symptoms are chest pain, shortness of breath (particularly on exertion), and syncope (or fainting due to the lack of blood reaching the brain). Mrs. Bush was reportedly suffering from shortness of breath.
The smaller the cross-sectional area of the opening and the higher the pressure gradient across the valves, the more symptomatic the patient becomes. Traditionally, when all aortic valves were replaced with an opening of the chest via an incision in the sternum, the cut-off for severe aortic stenosis requiring surgery was an opening of 1 cm and a pressure gradient of 50.
The traditional way for the diagnosis to be made was through the use of echocardiography. This is the use of sound waves generating from a probe placed on the chest that are reflected back at different frequencies, thus generating a picture of the beating heart.
There are also suggestive findings on an EKG that are often the first clue, as well as the development of a characteristic heart murmur that can be a tip to the clinician that aortic stenosis is present. Newer modalities used to image the heart include MRI. Cardiac catheterization remains the gold standard for evaluating the condition but is an invasive test associated with a 1% risk of death for the patient.
Because of the relatively advanced age of Mrs. Bush, she will most likely receive a tissue valve made from a pig that will not require lifelong anticoagulation.
Tissue valves do not last as long as mechanical valves made from synthetic material but do not have the risk of forming clots and do not require lifelong anticoagulation.
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