Peripheral artery disease

Peripheral artery disease

Pathology

Peripheral artery disease is a set of acute or chronic syndromes derived from the presence of occlusive arterial disease that causes the inadequate flow of blood in the limbs. In most instances, the arteriosclerotic disease is the underlying disease process that mainly affects the vascularization to lower limbs. Pathophysiologically, lower limb ischemia is classified as either functional or critical. Functional ischemia is experienced when the flow of blood at rest is normal but becomes insufficient when exercising, thus clinically presenting as intermittent claudication. Critical ischemia is experienced when blood flow reduces, resulting in a perfusion deficit whenever at rest. The latter is defined by the presence of trophic lesions in the legs or pain at rest. The occurrence of such situations requires a precise diagnosis as an individual risk losing a limb if the adequate flow of blood is not re-established either by endovascular therapy or surgery. The two concepts must be adequately differentiated for the better establishment of the therapeutic indication as well as prognosis for the PAD patients.

Diagnosis

Several tests can be used to diagnose peripheral artery disease, and they include a physical exam, Ankle-brachial index, ultrasound, Angiography, and blood tests.

• Physical exam; signs of PAD may be found during a physical examination such as absent or weak pulses that appear below the narrowed area of the artery. The stethoscope could also be used to hear whooshing sounds over highways. Other indications include poor wound healing in areas where the flow of blood is restricted, and a decrease in blood pressure in the affected limb.
• Ankle-brachial (ABI ); this is a standard test used by the doctors where blood pressure in the ankle is compared to that in the arm.
• Ultrasound; the doctors can use Doppler ultrasounds to evaluate blood flow through vessels as well as identify narrowed or blocked vessels.
• Angiograph; this is where dye is used by being injected into your blood vessels, then the doctor views the flow of blood through the arteries.
• Blood tests; blood samples could be used to check on triglycerides and cholesterol as well as diabetes.

Chronic venous insufficiency

Pathology

The pathology of the disease is not yet fully understood. Venous reflux is based on many mechanisms, with the leading players being an inflammation of the vessel walls, venous valve incompetence, hemodynamic factors, and venous hypertension. The mechanisms can further be aggravated by muscular pumps and vascular pumps in mobile patients or the ones having stiff joints. Vessel wall inflammation could be as a result of changes in shear stress. Evidence shows that normal shear stress leads to anti-inflammatory effects, while low shear stress like reflux leads to increased discharge of pro-inflammatory messengers. The aforementioned hemodynamic changes and venous hypertension are associated with the release of vasoactive substances from the endothelium that gives rise to the expression of adhesion molecules. There is an increase in the levels of collagen in the vessel wall of patients that have the chronic venous disease as the amounts of laminin and elastin are lower than usual. Patients with venous ulcers always have a combination of venous reflux and obstruction.

Diagnosis

The diagnosis of the disease s based on history, diagnostic tests, and clinical presentations. Apart from the duplex ultrasound that is the standard, other diagnostic procedures can be used under different circumstances, and they include;

• Phlebography; is an imaging technique that uses an x-ray to study the veins in the legs.
• Plethysmography; is based on the measurement of infrared light that is reflected by hemoglobin to determine the time used by the venous to fill the subcutaneous venous plexus.
• Phlebodynamometry; it refers to the intravascular measurement of the venous pressure of the periphery.
• Other methods include CT and MRI for leg vein imaging.