An aneurysm is an abnormal bulging or widening of an artery. Arteries are the blood vessels that carry oxygen-rich blood from the heart to different parts of the body. Aneurysms can occur in any artery, but most frequently involve the aorta, the largest artery in the body. The aorta originates at the heart and then travels upward in the chest toward the head (the ascending aorta), giving rise to the arteries that supply blood to the arms and head. It then makes a u-turn (the aortic arch) and heads downward in the chest (the descending aorta) and then into the abdomen (abdominal aorta) giving rise, along the way, to many arterial branches that feed the rest of the body. Aortic aneurysms in the chest are called thoracic aortic aneurysms, and those that occur below the diaphragm are referred to as abdominal aortic aneurysms. Aneurysms can be caused by arteriosclerosis, high blood pressure, injury, inherited conditions (i.e., Marfan syndrome), connective tissue disorders or infection.
Each year, approximately 33,000 patients in the US undergo elective aortic aneurysm repair to prevent rupture. Abdominal aortic aneurysm rupture leads to nearly 9,000 deaths annually. Surgery to repair abdominal aortic aneurysms has been performed for more than 50 years, and over time, there have been a number of improvements in surgical therapy. The most important recent development is endovascular (“within the blood vessel”) repair of abdominal aortic aneurysms. Ruptured aneurysms cause an overall mortality rate of 90 percent. Only 50 percent of patients who reach the hospital with a ruptured aneurysm will be able to survive surgery, and some of these individuals will be unable to return to their previous lifestyles.
Clearly, it is much better to electively operate on an aneurysm than to try to repair an aneurysm once it has ruptured. Elective aneurysm surgery is performed with a less than 2 percent mortality rate, and almost all patients are able to return to their usual lifestyles, including patients in their eighties. Surgery is recommended when the benefits outweigh the risks, as identified during careful preoperative evaluation. Preoperative evaluation typically includes a cardiac stress test, pulmonary function studies, renal function studies, a medical history and physical examination and routine laboratory tests.
Abdominal aortic aneurysms less than 4 centimeters in diameter are considered “very small.” Their risk of rupture is essentially negligible. Two recent, large, randomized trials, the United Kingdom Small Aneurysm Trial and the Aneurysm Detection and Management Corporative Study (reported on in the May 9, 2002, edition of the New England Journal of Medicine), showed no improvement in survival rate with surgery for abdominal aortic aneurysms between 4 and 5.5 centimeters in diameter. Therefore, it is quite clear that patients with aneurysms of this size should not undergo surgery unless there are extenuating circumstances. These patients should, however, carefully monitor their health and go to the nearest emergency room if they experience any new abdominal or back pain that is not muscular or skeletal-related.
Patients with aneurysms 5 centimeters or larger should consult a vascular surgeon for an evaluation that includes an assessment of general surgical risks and the anatomy of the aneurysm, as well as a discussion of which potential symptoms to be aware of.
Elective, open surgical repair in “good risk” patients can be performed with a less than 2 percent mortality rate. Patients who undergo open repair of abdominal aortic aneurysms are typically walking around in two or three days and are back to a regular diet by postoperative day six. The majority of patients are discharged from the hospital on the sixth or seventh postoperative day. After discharge, they can generally drive in two to three weeks, but may experience some fatigue for two to three months. Endovascular (“within the blood vessel”) therapy is relatively new. As such, there are still issues that need to be resolved. For example, the long-term durability of endovascular grafts is unknown. Consequently, patients who have these grafts require careful lifelong follow-up. As many as 10 percent of patients require an additional procedure each year to ensure that the grafts continue to function as intended. On a positive note, the technology for endovascular grafts is rapidly improving, making them a more attractive option. Currently, patients who receive grafts experience less pain and little early morbidity, and they are usually back to normal within a month of the procedure.
At the Lahey Clinic we feel endovascular grafts should be reserved for relatively high-risk patients with good anatomy until more is known about their long-term effects. Lahey's vascular surgeons are also interested in treating peripheral aneurysms in the carotid artery, popliteal artery, femoral artery, visceral vessels and elsewhere. For further information, please contact the Department of Vascular Surgery at 781-744-8577.