Atherosclerosis represents a buildup of cholesterol and calcium in an artery, resulting in “plaque” that progresses to block off the artery. This disease may affect any artery in the body and is often present in multiple locations. The most common locations for atherosclerosis are:
- arteries in the heart, known as coronary atherosclerosis;
- arteries that supply the legs, known as peripheral arterial disease (PAD);
- arteries that supply the brain, known as carotid artery disease.
Advanced atherosclerosis in these areas can lead to heart attack, amputation or stroke. Less commonly atherosclerosis can affect arteries that supply the kidneys or the intestine, which may lead to dysfunction of those organs. Atherosclerosis of the arteries to the arms does occur but it is relatively rare.
Risk Factors for Atherosclerosis
- AGE: Atherosclerosis is part of the aging process. In general, men over 45 and women over 55 are believed to have an increased risk for atherosclerosis. It is unusual to have clinically significant atherosclerosis below the age of 50; however, by the time a person reaches 65 years of age, there is a 10-20% chance that s/he will have some manifestation atherosclerosis. This may be evidenced either by symptoms or upon examination. In most cases, atherosclerosis can be managed without surgery through the modification of factors that speed the progression of this condition.
- HEREDITY: Atherosclerosis often runs in families, so it is important to know your family history of heart attack, stroke or amputation, or sudden death and discuss it with your primary care practitioner. Abnormalities of cholesterol (dyslipidemia) or blood sugar (diabetes) also run in families. Both of these conditions can increase the risk of developing atherosclerosis.
- SMOKING: Smoking of any sort is the single most important modifiable risk factor for progression of atherosclerosis. Patients who smoke are at significant increased risk of heart attack, stroke or amputation and people who continue to smoke are at higher risk than those who have stopped. The combination of smoking and diabetes is particularly detrimental. If you are found to have atherosclerosis of any sort, you should make every effort to stop smoking. There are a number of smoking cessation aids, medications and counseling strategies that can improve your chances of quitting; however, the most important factor is the determination to quit.
- HIGH CHOLESTEROL: Abnormally high levels of LDL (“bad cholesterol”) and triglycerides both increase the risk of atherosclerosis, while higher levels of HDL (“good cholesterol”) are beneficial. Goals for cholesterol levels vary with the number of risk factors each person has (age, hypertension, smoking, family history, HDL<40).
Targets for LDL are:
- <130 mg/dl for ≥ two risk factors
- <100 mg/dl for > two risk factors
- <70 mg/dl for > two risk factors and diabetes or renal disease
Targets for triglycerides are:
- <150 mg/dl.
Target for HDL is:
- ≥ 40 mg/dl.
- DIABETES: The presence of diabetes increases the risk of atherosclerosis. In general, individuals whose diabetes is well controlled can reduce their risk of stroke, heart attack and death. “Good control” is defined as HgbA1C between 6 and 7. There is no evidence that suggests lower levels provide any additional benefits. Diabetics should not smoke as smoking further accelerates risks of atherosclerosis in diabetes.
- HIGH BLOOD PRESSURE (HYPERTENSION): High blood pressure increases the risk of heart attack, stroke and death. There isn’t much evidence that moderate elevations of blood pressure independently increase the progress of atherosclerosis; however, every effort should be made to control blood pressure to within medically established guidelines (140/90 or lower).
- OBESITY: There is no direct evidence that obesity itself increases the development of atherosclerosis. However, obesity is associated with several risk factors (diabetes, cholesterol abnormalities) that are risk factors atherosclerosis. In addition, obesity places added stress on the heart and lungs as well as muscles and joints and increases problems with venous disease. For these reasons, every effort should be made to avoid obesity. Body Mass Index (BMI) is the typical measure for obesity—individuals should target a BMI of less than 30.
Preventive Measures to Reduce Progression of Atherosclerosis
While you cannot reverse the aging process or choose your parents, there are a number of things that can be done to reduce the risk of progression of atherosclerosis. These include:
- Stop smoking—smoking cessation is the single most important way to reduce atherosclerosis progression.
- Control diabetes— speak with your primary care physician if this is a concern and don’t smoke.
- Lower cholesterol—speak with your primary care physician if this is a concern.
- Watch hypertension—take action to keep blood pressure within normal guidelines.
- Reduce obesity—aim for a BMI of 30 or less.
- Exercise regularly—including 45-90 minutes of exercise three to five times per week, even at modest levels, will help with weight reduction and can elevate levels of HDL (good cholesterol).
- Enjoy a Mediterranean diet—learn more about the foods enjoyed in the Mediterranean that have health benefits and may reduce total cholesterol and LDL.
- Medications—a variety of medications have been designed to reduce risk factors (such as lower cholesterol and triglycerides), each with their own indications, side effects and complications. Plus, new drugs are being developed and tested every day. You should speak with your primary care practitioner to determine what medication, if any, is right for you.
Since diet and exercise are measures that most people can do on their own and are not associated with complications, this should be the first step, along with smoking cessation. If you are starting an exercise regiment for the first time, consult your primary care practitioner before beginning.
Peripheral Arterial Disease (PAD)
PAD is a type of atherosclerosis that involves the blood vessels supplying circulation primarily to the legs (less likely in the arms). It is a common condition and studies have shown that PAD can be identified in 5% of individuals between 60-69 years of age and in 15% of individuals who are 70 years of age or older.
PAD prevalence increases with age and is more common in individuals who smoke or have one of the risk factors described. PAD is increased in patients who have had heart attack or stroke or who have had any vascular surgery, including angioplasty.
Symptoms of Peripheral Artery Disease
Claudication: Claudication comes from the Latin word for “limp.” It is defined as pain, tiredness or weakness in the muscles of the calf, thigh or buttocks that occurs with exercise (walking), which is then relieved when you rest or stop the activity. Symptoms of claudication result from the muscles’ increased demands for oxygen during physical activity that cannot be met due to reduced blood flow from narrowed or blocked arteries. As a result of impaired circulation, leg muscles will tire or become painful (cramping or weakness). Symptoms of claudication are very repeatable and often occur after the same type of activity (walking, climbing stairs or a hill) and do not occur in the muscles of the foot. It can often be managed medically and, in most cases, there is a low risk of amputation.
Pains in the leg that are not brought on by exercise but instead occur during rest or after prolonged standing or sitting are not generally related to vascular disease. There may be many other causes of leg pain (arthritis, back problems, neuropathy).
Critical Limb Ischemia (CLI): When the degree of blockage from PAD becomes severe, pain may occur without exercise and manifests in the foot, especially the toes (not the calf, hip or thigh). This is known as critical limb ischemia (CLI), and as the name implies, is an urgent condition that requires prompt consultation with a surgeon, as there is significant risk of amputation (unlike claudication).
In general, patients will experience a burning pain occurring most often at night, which can be relieved by sitting up, hanging your foot over the side of the bed or sometimes even by walking. With CLI, the foot may lose color when it is elevated or become deep red or purple when you stand or sit. Small areas of dead tissue (gangrene) may develop, usually on the toes or other pressure points on the foot.
In most severe cases, sores or ulcers may develop on the foot from minor injury—either on the toes or at sites of pressure (sole of foot or heel). If you develop a sore on the foot, especially if it does not heal quickly, you should be checked immediately for PAD.
Diabetic neuropathy (nerve pain) can sometimes be confused with CLI and the conditions can sometimes coexist. However unlike the pain of CLI, diabetic nerve pain usually occurs in both feet, is not made better by hanging your foot down and is not associated with changes in color of the foot.
Diagnosis of Peripheral Artery Disease
Although most patients with PAD have no symptoms, it can be easily and painlessly diagnosed in the doctor’s office and is painless. The process involves measuring the systolic blood pressure at the ankle with a Doppler probe and a blood pressure cuff, then comparing that reading to the highest blood pressure taken in either arm. The ratio of these pressures is called the Ankle/Brachial Index (ABI) and a normal ABI is 0.9 to 1.2. Generally, the lower the ABI, the more severe the PAD. For example, when an ABI is performed and the result is generally less than 0.45, you may have critical limb ischemia (CLI), a severe form of PAD that may result in amputation if left untreated.
You should discuss an ABI screening—which is more accurate than feeling for a pulse in the foot—with your physician after you reach the age of 55, or earlier if you smoke, have diabetes or high cholesterol. This can be done as part of your regular examination or in a vascular laboratory.
Prevention Strategies and Medical Management of PAD
Specific management strategies for symptomatic PAD differ depending on the severity of the symptoms—whether you have claudication or CLI. Patients with PAD are likely to have coronary artery disease or carotid artery disease, even if they are asymptomatic. Since stroke and death are common in patients with PAD, it is important to look for evidence of these conditions in all patients with PAD.
Medical Management of Claudication
It is important to remember that patients whose only PAD symptom is claudication are not in immediate danger of amputation. Only about 15-20% of patients whose only symptom is claudication will eventually progress to the point where amputation might be a concern. In fact, patients with claudication are more likely to have a heart attack than to have an amputation. Therefore the goals of treatment are symptom relief, identification of silent atherosclerosis in other areas (heart, carotid arteries), and general treatment of atherosclerosis to prevent worsening of the condition or problems of myocardial infarction or stroke. Management techniques include:
- Stop Smoking—smoking cessation is critical with PAD.
- Supervised Exercise—regular exercise on a treadmill, while it is time consuming, has been shown to be equivalent to or better than angioplasty or bypass for most patients with claudication. For this strategy to be effective, patients need to work up to 45 minutes per day at a speed of 2.5 miles per hour using a 10% incline for 3-5 times per week. Since many patients are often initially too physically limited, we recommend that this is done in short segments that add up to 45 minutes over the course of the day. Patients who do not have access to a treadmill should walk as briskly as possible for as long as they can to total 45 minutes. This should be done as often as possible but no less that 3-4 times per week. This routine works by building up tolerance in your leg muscles. While you may get pain when you walk, you cannot damage your muscles by walking as long as possible. More than 60% of patients will see symptom improvement when combining smoking cessation and exercise.
- Antiplatelet Agents – because of the risk of heart attack and stroke, all patients should be on an agent that reduces platelet clumping. The two most common agents are Aspirin (81 or 325 mgm/day) and Clopidogrel (Plavix) 75 mgm/day.
- Cilostazol (Pletal)—this drug has been shown in blinded comparison to improve walking distance in the majority of patients. This drug works by increasing the ability of red cells to go through small arteries. Patients generally start at 50 mgm twice per day and increase to 100 mgm twice per day if tolerated. Side effects include nausea or GI upset, lightheadedness and sweating. About 60% of patients can be helped by this medication in our experience; however it is not covered by all insurance carriers and is expensive. Pletal should not be given to patients with congestive heart failure.
- Statins—there is a controlled trial that demonstrates improvement in walking for patients who take statins, even at low doses. The basis for this improvement is not known.
Medical Management of CLI
In the case of CLI, the circulation has deteriorated to the point that it must be improved rather than stabilized. The major goals in patients with CLI are to relieve pain, heal ulcers and prevent amputation. While medical management techniques are similar for claudication (see above), and smoking cessation is critical, medical management is usually not sufficient in patients with CLI. Pletal has no clear role in patients with CLI, so intervention is often required.
Intervention for Claudication
Patients who have failed in the medical management of claudication may be considered for intervention. Some patients are so incapacitated by their symptoms that they choose intervention as the initial treatment. This is acceptable as long as the patient realizes all interventions are associated with risk and that all of them are subject to failure at some future date. Patients may be treated by “endovascular” surgery (angioplasty with or without stents) or surgical bypass. The choice of intervention will be determined after discussion with the surgeon and will be based on the location and severity of the disease, the overall health of the patient and patient preference and expectations.
Some things to consider prior to intervention for claudication include:
- How bad are my symptoms? Do they require intervention or can I try exercise and medication? Remember the goal of intervention is to reduce symptoms; amputation is unlikely in patients with claudication.
- Is the blockage short enough that angioplasty will give a good result? Am I willing to have a second intervention within two years if angioplasty fails?
- Am I healthy enough for surgical bypass? Am I willing to recover for 4-8 weeks from surgery knowing that this often provides a superior long-term result?
A general comparison between Angioplasty/Stent and Surgical Bypass is shown in the table below. In general, after any intervention, patients should begin an exercise program and take an aspirin and statin to reduce the risk of recurrent problems. Cilostazol should not be needed after a successful intervention.
|Comparison of Angioplasty/Stent and Surgical Bypass for Claudication|
|Preferred in:||Larger vessels||Smaller vessels (<4 mm)|
|Preferred in:||Shorter blockages||Longer Blockages (>20cm)|
|Hospital Stay:||Outpatient or Overnight||Inpatient (3-7 days)|
|Anesthesia:||Local with sedation||General or Spinal|
|Recovery at home:||One week or less||3-4 weeks|
|Durability:||About 50% at 2 years||60-75% at 5 years|
Intervention for CLI
Since intervention is usually required for CLI, patients will need a study (ultrasound, angiogram) to determine the extent of the blockage and plan either angioplasty or surgical bypass. Furthermore, patients should be evaluated for coronary artery disease, which is present in almost all patients with CLI. When possible, any significant coronary disease should be controlled before CLI intervention. Patients with CLI are generally older and sicker than patients with claudication and their disease is more extensive. Consequently, advanced endovascular techniques may be required to achieve success in these circumstances.
Recommendations on preferred treatment of patients with CLI are evolving and treatment decisions should be made after consultation with a vascular surgeon who is experienced in both open surgical bypass and advanced endovascular techniques. A large study comparing endovascular surgery and open surgical bypass suggests that endovascular gives equal results with less complication rates for the first two years, but after that, open surgery is superior. Therefore, decisions on appropriate therapy depend on many factors including the patient’s overall medical condition.
Post Intervention Care—after intervention, patients should take aspirin, Clopidogrel or both. Clopidogrel is recommended for at least 6-8 weeks, after which aspirin alone is sufficient. Patients should be on a statin drug and should continue risk reduction, which includes no smoking and control of diabetes, cholesterol and high blood pressure. The most common problem after intervention (besides recurrence) is myocardial infarction and patients should follow up with their primary care physician or cardiologist to prevent this condition.
After any intervention, patients should be seen regularly for life. Any intervention can fail, but if caught in time, the problem can be corrected. Most failures occur during the first two years after intervention. Therefore, it is recommended that patients see their surgeon after one month, and every 3-6 months thereafter for two years. If everything looks good at two years, annual follow up is sufficient. If symptoms recur at any time, you should go back to your surgeon.
Carotid Artery Disease
Atherosclerosis of the carotid arteries is important because it is a major cause of stroke. There are about 750,000 new strokes per year in the United States and about 20% are associated with disease of the carotid arteries in the neck. Furthermore, about two-thirds of strokes occur without warning. While most strokes occur in patients without carotid artery disease, when a stroke does occur, it is important to know whether or not significant carotid disease is present. “Significant” carotid disease narrows the carotid artery more than 50%. The more severe the narrowing, the more concerning the disease.
Symptoms of Carotid Artery Disease (Carotid Stenosis)
Any adult patient who has a stroke or Transient Ischemic Attack (TIA or “ministroke”) should be checked for disease of the carotid arteries in the neck. However, most patients with carotid artery disease are asymptomatic. In these patients, carotid stenosis can be suspected when a noise, or bruit, in the neck is heard with a stethoscope during a physical examination.
While there may be several causes for such a bruit, individuals over the age of 60, or with a history of stroke, myocardial infarction, coronary bypass or angioplasty PVD, and/or smoking are more likely to have carotid disease. Significant carotid stenosis is rare in the overall adult population (less than 2%), but is present in 20-30% of individuals with stroke or TIA and in 5-10% of patients with a bruit who are over 60, smokers or have a history of coronary or peripheral artery disease.
Diagnosis of Carotid Artery Disease (Carotid Stenosis)
Carotid artery disease is easily checked by Carotid Duplex Ultrasound. This is a simple non-invasive study that can detect plaque in the carotid arteries and determine the degree of blockage. You should talk with your primary care physician about whether or not you meet the criteria for a carotid ultrasound. Remember, not all insurance will pay for carotid ultrasound in patients without symptoms. Like PAD, the major long-term risk of carotid disease is myocardial infarction and cardiac evaluation along with risk reduction is very important in overall management.
Relationship between Stroke and Carotid Artery Stenosis
While there are many causes of stroke, carotid stenosis is thought to cause about 20-25% of strokes in adults. Patients who have a stroke and are found to have a carotid stenosis have about a 30% chance of experiencing a second stroke, most often during the first weeks to one month after the initial event. Therefore, adults who have a stroke should be checked for carotid stenosis.
The importance of carotid disease in patients without symptoms of stroke is more controversial. Narrowing of the carotid arteries by more than 50% is present in 2-4% of individuals over the age of 65; however, most of these people will never have a stroke. About 60-70% of patients who have a stroke have no warning signs, and therefore, the only suggestion that they have carotid disease may be a bruit in the neck or finding narrowing with a Carotid Duplex Ultrasound.
When carotid artery stenosis is found in an asymptomatic individual, the overall risk of stroke and death is increased. The risk of stroke increases with the degree of stenosis.
- Narrowing of the carotid arteries less than 50% is considered part of normal aging.
- Narrowing of the carotid arteries between 50-70% carries a low risk of stroke and should be monitored.
- Narrowing of the carotid arteries more than 70% carries a 2-4% risk of stroke per year (10-20% over five years).
There is a common agreement that the general screening of all individuals for carotid disease is not necessary. However, there are certain circumstances where the likelihood of carotid disease is increased and screening may be considered. Patients over 60 years of age, who have more than one of these factors in their history, should consider screening studies. These include:
- patients with coronary disease or PAD,
- patients with a murmur (bruit) in their neck, and
- patients with a history of stroke or “ministroke” (TIA).
Intervention for Carotid Stenosis
- Patients with Stroke or TIA: Any patient with symptoms of a stroke or ministroke (TIA) who has a carotid stenosis more than 50% should be considered for intervention. The more severe the stenosis the more likely intervention should be performed. Comparison of medical treatment and surgery (carotid endarterectomy) in patients with symptoms of stroke or TIA has been done in many thousands of patients over several decades. Surgery will reduce the risk of future stroke from 15-30% to less than 5% in these patients. Whenever possible surgery should be done within two weeks of first symptoms. There is little controversy over the role of surgery in symptomatic patients with stenosis greater than 50%.
- Asymptomatic Patients: All asymptomatic patients with carotid plaque should be treated by control of diabetes, cholesterol, blood pressure and smoking cessation as well as aspirin therapy and a statin. In patients with narrowing of greater than 70% who are otherwise healthy, intervention may be considered. Comparison of surgery added to medical management versus medical management alone in asymptomatic patients has also been studied in several thousand patients. The benefit in asymptomatic patients is not as great as in patients who have had stroke or TIA. The overall risk of stroke in asymptomatic patients with carotid stenosis more than 70% is about 2-4% per year (10-20% over five years). Surgery can reduce this risk to 5-6% over the same timeframe. In other words, most patients who have carotid stenosis without symptoms will not have a stroke and this risk can be further reduced by surgery. To benefit from surgery, asymptomatic patients should have a narrowing of more than 70% and a life expectancy of at least 3-5 years. The role of surgery is asymptomatic patients is not universally accepted.
The benefit of surgery depends on the experience of the surgeon performing the operation and the overall health of the patient. In general, a surgeon performing Carotid Endarterectomy should have a complication rate (stroke plus death) of less than 6% in patients with symptoms and less than 3% in patients without symptoms. Experienced surgeons often have complication rates significantly less than that. It is important to know the surgeons results before considering surgery.
Treatments for Carotid Artery Stenosis
Carotid Endarterectomy (CEA): This is the standard treatment for carotid artery stenosis and is a procedure has been perfected over more than 50 years. It involves a 4-6 inches long incision in the neck to expose and clean out the diseased carotid artery. The procedure can be done under general anesthesia or regional (block) anesthesia depending on surgeon and patient preference. A hospitalization of 24-48 hours is routine. Post-operative pain is minimal and patients can return to normal activities in about a week. Experienced surgeons can perform CEA with complication rates of 3-4% in symptomatic patients and 1-2% in asymptomatic patients.
Carotid Artery Stenting (CAS): This procedure has been used to treat carotid stenosis for more than 15 years. It was initially used to treat patients who were felt to be at increased risk from carotid endarterectomy. Like other endovascular surgery, CAS is performed under local anesthesia through a puncture in the groin. Patients usually have a 24-hour stay in hospital and are back to full activity within 48-72 hours.
Complication rates for CAS are higher than those after CEA—6-8% for symptomatic patients and 3-4% for asymptomatic patients. Complications after CAS are also higher in patients over the age of 70 and in those with neurological symptoms. Because of this, CAS is only recommended in patients with symptoms of stroke or TIA when CEA is felt to be dangerous, and is not recommended for asymptomatic patients. Currently Medicare and most insurance companies will not pay for CAS in patients who are asymptomatic unless they are in a clinical trial. Comparison of CAS and CEA based on many clinical trials is presented in the table below.
It is important to discuss specific complication rates, including stroke, death, myocardial infarction and local site complications with the operator performing the procedure.
|Comparison of Carotid Endarterectomy and Carotid Artery Stenting|
|Carotid Stenting||Carotid Endarterectomy|
|Anesthesia:||Local||General or Local Block|
|Hospital Stay:||24 hours||24 – 48 hours|
|Return to Full Activity:||2-3 days||7-10 days|
|Complication Rate (Stroke/Death):||6-8% for symptomatic patients
3-6% for asymptomatic patients
|3-4% for symptomatic patients
1-2% for asymptomatic patients
|Patients with Stroke or TIA:||When Carotid Endarterectomy is “high risk”||All other patients|
|Asymptomatic Patients:||Currently not recommended outside of clinical trials||Good surgical risk, life expectancy 3-5 years minimum|
Intervention Follow Up
After intervention, patients should be maintained on aspirin or Plavix (both if CAS is performed) and a statin. Plavix may be stopped in 2-3 months as long as aspirin is maintained. General risk factor reduction including smoking cessation is important. A postoperative ultrasound is usually done within the first month to check the results of intervention. Recurrence after either CAS or CEA is less than 10%, so ultrasound can be done at six months, 12 months and two years. If there is no evidence of recurrent disease at that time and the other carotid is normal, no further follow up is required. If disease is present in the other carotid, or recurrent disease occurs in the original artery, further follow up may be required.
Aneurysms (Aortic Aneurysm)
An aneurysm is a bulging or ballooning of a blood vessel that is more than 150% of vessel’s normal size. This occurs because of damage to the vessel wall. The diameter of the artery is bigger in an aneurysm while it is smaller in atherosclerosis. The most common artery to develop an aneurysm is the aorta, followed by the iliac artery, femoral artery and popliteal artery. Aneurysms of other arteries outside the brain are uncommon. The following discussion is restricted to aortic aneurysms.
The major concern about aneurysms is that they will rupture which may lead to bleeding and death. The risk of rupture is generally related to the diameter of the aneurysm. However there are additional factors that increase risk of rupture particularly smoking, poorly controlled hypertension and family history. The chart below relates the size of aortic aneurysms to the annual risk of rupture.
|Aorta Rupture Risk Table|
|Diameter of Aorta*||Risk of Rupture per Year of Observation|
|less than 4 cm||Less than 1 %|
|4 – 5 cm||0.5 – 1.5%|
|5 – 5.5 cm||1-2%|
|5.5 – 6 cm||2-10%|
|6 – 7 cm||11-20%|
*Data for Males. Generally, aneurysms in females rupture at a slightly smaller diameter (about ½ cm less).
Some aneurysms, particularly those in the femoral or popliteal arteries, may clot off causing loss of blood flow to the legs. This is uncommon with aneurysms in larger arteries.
Risk Factors for Developing an Aneurysm
- AGE: For the most part, aneurysms are a disease of aging. Clinically significant aneurysms are uncommon before the age of 65, but incidence increase as a person ages beyond 65. Women typically develop aneurysms at a later age than men do, and most patients who require surgery for aneurysms are in their 70s or 80s.
- HEREDITY: There is evidence that some aneurysms are inherited. If a parent, grandparent or sibling had an aneurysm, your chances for an aneurysm increase by 3-4 times. The tendency to form aneurysms appears to be linked to the X chromosome, so if your mother’s family has a history of aneurysm that is particularly important to share with your physician. Aneurysms are more common in men than women because of this sex-linked inheritance. There are certain types of aneurysms that are related to known genetic defects (Marfan’s Syndrome, Loey’s Dietz syndrome). In these cases aneurysms develop at an early age.
- SMOKING: Smoking increases risk for aneurysm growth and rupture.
- HYPERTENSION & COPD: These conditions, if poorly controlled, increase risk of aneurysm growth and rupture.
Symptoms of an Aneurysm
Larger aneurysms can be felt as a bulging or pulsating mass in the abdomen on routine examination. Your doctor should be feeling your abdomen for aneurysms as a part of a routine examination once you reach the age of 60 or 65. Not all aneurysms can be felt, particularly in overweight or very muscular patients. Similarly, not all pulsating masses are aneurysms—a pulsating mass in a thin individual may just be a normal size aorta.
Diagnosis of an Aneurysm
The best way to look for aneurysms is by an abdominal ultrasound, which is a painless, non-invasive examination. Medicare will pay for one screening ultrasound in all males over the age of 65. Experience shows that this screening will detect aneurysms in about 2-4% of patients. Medicare currently does not pay for screening females since the incidence of aneurysm in women is only about ¼ of that in men. However, if you have a family history of aneurysm disease or a significant history of smoking and hypertension, you should consider an ultrasound examination if you are over the age of 65.
Treatment of Aneurysm
Not all aneurysms require surgery. In fact, based on the rupture risks in the table, a decision should be made whether to observe the aneurysm or consider intervention. In general terms, aneurysms in the Thoracic aorta are usually observed until they reach 6 cm (men) and 5.5 cm (women). This is due in part to the larger size of this vessel and in part to the specific complications associated with operation on the aorta in the chest. Abdominal Aortic Aneurysms less than 5.5 cm in men and 5.0 cm in women can be safely observed, since the rupture risk is 1% per year or less. As a rule, an aneurysm grows at a rate of about 10% per year. Therefore, an aneurysm 4.5 cm or less can be checked every 1-2 years while an aneurysm 4.5 cm or greater should be monitored every 6-12 months. During the follow up period, it is important to stop smoking and control your blood pressure. There is some evidence that some drugs (propranolol, doxycycline) may slow the growth of aneurysms, but this is not currently universally accepted. Aneurysms are usually monitored by ultrasound. CT scan is reserved for patients who are being considered for surgery.
Intervention for Aneurysm
Patients with aneurysms larger than 4.5 cm should consider surgical intervention. The type of surgery and the specific decision about intervention is a complex one that depends on the size and location of the aneurysm (particularly whether it is above or below the arteries to the kidneys and intestines), your state of health, your life expectancy, and whether or not a stent graft or endograft can be successfully used. You and your surgeon need to consider the risk of intervention compared to the risk of rupture with observation. Some surgeons will consider operation on young, healthy individuals when an aneurysm reaches 5 cm (males) or 4.5 cm (females). At that diameter, there is a 60% likelihood that the aneurysm will require surgery in the next 3-5 years. Patients who are expected to live at least that long maybe good candidates for surgery.
There are two approaches to aortic aneurysm surgery—Stent Graft (Endograft) repair and traditional surgical repair, which are compared in the following table.
|Comparison of Aortic Aneurysm Surgery Approaches|
|Stent Graft (Endograft )||Traditional Surgery|
|Incision:||Minimally invasive groin incision or no incision||Abdominal or Flank Incision|
|Hospital Stay:||24-72 hours||7-10 days|
|Return to Full Activity:||1-2 weeks||3-4 months|
|Complications:||May be difficult when aneurysm is close to renal arteries||Increased risks in older and sicker patients|
|Follow Up:||Lifelong follow up necessary, 10-15% need for additional surgery||Follow up less important, 3-5% need for further surgery|
Endografts are generally preferred for treating aortic aneurysms (when feasible) and are used in 70-80% of cases. They can be performed with lower mortality rates in patients over 80 (2% vs. 8-10%) or in individuals who have other medical illnesses. However, there are certain types of aneurysms where an endograft is not the best choice because of aneurysm location or curvature of the aorta. A CT scan is required to determine the feasibility of endograft repair. Endografts may fail even years after they are placed, so if this approach is selected, patients must be committed to long-term follow up through ultrasound or CT scan every 6-12 months, indefinitely. New endografts are being developed that should solve some of the technical problems associated with current models, extend their use and improve their results.