Peripheral arterial disease (Peripheral vascular disease)
Peripheral arterial disease is caused by atherosclerosis of the arteries of the lower extremities leading to narrowing or complete occlusion of the vessels.
Approximately 200 million people worldwide suffer from peripheral arterial disease, which is why it has been designated as a major global health problem. Population ageing, as well as the increasing incidence of diabetes, smoking, hypertension and hyperlipidemia are the leading causes of peripheral arterial disease.
The arterial system of the lower extremities
Blood supply to the lower extremities is carried out by large, medium and smaller arteries.
Starting from the abdominal aorta, it divides at the level of the umbilicus into the right and left iliac arteries which are responsible for the perfusion of the pelvis and they also bring blood to the arteries of the lower extremities.
Common femoral artery, superficial femoral, deep femoral, popliteal and tibial arteries are the arteries perfusing the lower extremities.
Atherosclerosis can occur in any of these arteries and causes narrowing or complete blockage.
Risk factors
Peripheral arterial disease risk factors:
- Age (>60 years)
- Smoking
- Diabetes
- Hypertension
- Hyperlipidemia
Symptoms
Patients with peripheral arterial disease may have no symptoms and the disease may be detected in a random screening. However, even without symptoms, peripheral arterial disease is an important predictor of cardiovascular and myocardial infarction risk.
About 10% of asymptomatic patients will develop symptoms of intermittent claudication over a 5-year period.
What is intermittent claudication?
Intermittent claudication is the pain that occurs in the lower extremities with walking or exercise which subsides with rest. This pain is caused by the reduced blood flow in the leg and depending on the location of the narrowing/obstruction it can be located in the buttocks, the thigh or more often in the calves.
Depending on the distance the patient can walk, and how the pain affects his daily activities and lifestyle, the severity of the intermittent claudication is determined.
The prognosis is good, especially with exercise and smoking cessation. A small percentage, however, may worsen and develop critical lower limb ischemia.
What is Critical Limb Threatening Ischemia?
Critical limb threatening ischemia of the lower extremities is the most severe stage of peripheral arterial disease and the patients can present with continuous pain in the leg even at rest, as well as ulcers (wounds) or gangrene.
Patients with critical ischemia are at risk of amputation. Immediate attention and thorough examination of the arterial system is imperative. The choice of the appropriate treatment depends on the characteristics and location of the obstruction as well as the general condition of the patient.
Diagnosis
The diagnosis of peripheral arterial disease is usually made through physical examination and patient’s history.
Depending on the symptoms, the following may be performed:
- Ankle-brachial Index (ABI): We check the blood pressure in the area of the ankle and in the upper extremity with a Doppler ultrasound and a blood pressure cuff. By dividing these two numbers we derive an index which shows us the severity of the disease.
- Pulse volume recording: With this examination, the blood flow pressure in various levels of the lower extremities is checked and the flow waveforms are recorded, in order to diagnose narrowings and blockages of the arteries.
- Arterial ultrasound – duplex: The arteries are checked with ultrasound that gives us information about the arteries and the blood flow. It can show stenosis and blockages. With the duplex we can evaluate from the level of the abdominal aorta to the arteries of the leg.
- CT angiography: CT angiography is computed tomography with contrast injection that gives us detailed information about the arteries with precise imaging. It is often the most precise exam for diagnosis and planning of the surgery.
- Magnetic resonance imaging-angiography: Magnetic resonance imaging is also a reliable examination with the avoidance of radiation compared to CT, however, it is time-consuming and may be contraindicated in patients with metal implants and claustrophobia. In some cases such as popliteal artery entrapment syndrome and adventitial cystic degeneration of the popliteal artery, MRI is superior to CT and is the test of choice.
Classic Angiography: Classic angiography is an invasive procedure. Requires usually a puncture of the femoral artery in the groin area and injection of contrast. It is now performed as part of therapeutic management and rarely as an exclusively diagnostic procedure.
Treatment
The Vascular Surgeon is the only specialist who can offer the full spectrum of treatments, from simple conservative treatment to complex endovascular and open revascularization procedures. For this reason, the decision of the appropriate treatment is always made after a discussion with the patient and his family, discussing all the data regarding the stage of the disease and the treatment options.
The most important first step for all patients with peripheral artery disease is to improve lifestyle, reduce risk factors and take appropriate medications.
- Quit smoking
- Reduction of “bad cholesterol” (LDL): The goal is for patients with peripheral artery disease to have LDL less than 100 mg/dL, while in high-risk patients less than 70 mg/dL. Appropriate statin medication is important in conservative treatment.
- Antiplatelet medications (aspirin)
- Healthy diet and weight loss
- Diabetes control
It is important to understand that all of the above measures are reducing cardiovascular risk overall.
Exercise and Intermittent Claudication
Exercise is the cornerstone treatment of intermittent claudication. We recommend 30-45 minutes of walking 3-4 times a week for at least 12 weeks. This exercise can be done either outside or on a treadmill. This exercise results in 200% improvement in walking distance in 12 weeks in great percentage of patients.
The mechanism by which exercise improves intermittent claudication has to do with angiogenesis (creation of new vessels and collateral network) but also with the dilation of collateral network arteries. At the same time, the vascular inflammation seen in peripheral arterial disease is reduced. This improves the blood supply to the lower limb and muscles, improving the symptoms of intermittent claudication.
Surgical (Open/ Endovascular) Treatment- Reperfusion Intervention
In these cases that conservative treatment does not improve the intermittent claudication, and the symptoms are very intense with a limitation of the patient’s activities (lifestyle limiting claudication), surgery and intervention is always an option.
In critical limb ischemia, reperfusion surgery is imperative as the risk of amputation is high.
The patient undergoes a pre-operative evaluation with a duplex ultrasound and/or many CT angiography to decide the appropriate treatment.
Endovascular treatment involves angiography usually by puncturing the femoral artery in the groin area and then with special wires and catheters we inject contrast to visualize the arteries. Based on the findings of stenosis or occlusion, special balloons and stents are used to open the blocked artery. Also, in case of acute ischemia, special catheters are used to remove the clot which is causing the blockage.
With modern techniques, the procedure for the revascularization can be performed from any artery of either the upper or lower limb, giving us the opportunity to give the best result with the least invasive procedure.
Left superficial femoral artery Chronic Total Occlusion and successful recanalization with stent placement
Depending on the patient’s general condition, the operation can be performed either under sedation and local anesthesia or under general anesthesia.
The patient remains one day in the hospital after the operation and leaves with specific instructions for proper hydration and gradual return to activities.
In patients with Chronic Renal Insufficiency, we can reduce the exposure to the contrast medium by using intravascular ultrasound.
Open surgery for revascularization may involve different techniques depending on the extent of the disease. It is usually performed under general anesthesia.
Endarterectomy: In stenosis or blockages mainly involving the common femoral artery, an incision in the groin area can be performed to “clean” the artery and remove the atherosclerotic plaque causing the stenosis.
Bypass: Bypass is performed when there are extensive narrowings or blockages in the arterial network. Examples of bypasses are:
- aorto-bifemoral bypass
- femoral-popliteal bypass
- femoral-tibial bypass
- axillary-bi-femoral bypass
Bypass can be performed by harvesting a vein from the patient or a prosthetic graft. The incisions that are made can be in the abdomen, the groin areas, the inner thigh or the calf. Depending on the type of thebypass, the patient can stay in the hospital from 2-5 days.
Benefits, potential complications, and patency (how long the artery or bypass stays open) of the specific procedures are discussed in detail during the office visits.
Many times a combination of endovascular and open surgery (hybrid surgery) is required. The Vascular Surgeon can perform these procedures simultaneously to achieve the best result. Performing these operations in modern hybrid operating rooms, such as that of the Athens Medical Center with the “Prometheus” Hybrid OR , increases safety and improves results.
