Summary
Peripheral Artery Disease (PAD) is a lot more common than previously believed. Diabetics and those who consume tobacco products are at high risk of the same. Amputation of a part, or entire foot, can be the outcome in extreme cases. That is why PAD is taken quite seriously. While incisional surgery and medication were the only treatment options in the past, in the last three decades, various invasive, non-invasive, minimally invasive and new-age treatment methods have emerged. In this article, we will examine some of them.
Introduction
Atherosclerosis is a condition in which cholesterol and other substances found in the blood start depositing on the walls of arteries. As deposits start accumulating, they harden into a material called plaque. Plaque deposits narrow down the artery and reduce blood-flow in it, leading to various complications. When atherosclerosis happens in the heart, it causes coronary artery disease (CAD), if it happens in the brain, it is called Cerebrovascular disease and when it happens in the lower extremities of the hands or legs, it leads to Peripheral Artery Disease (PAD). The condition is more common in the legs, and very rare in the hands.
Risk Factors for PAD include obesity, tobacco consumption, diabetes, high cholesterol, hypertension, kidney disease, older age and blood-clotting disorders. While atherosclerosis is the major cause for PAD, there are other causes such as thrombosis (blood-clots), artery spasm (temporary tightening of muscles of the wall of an artery, leading to reduced blood-flow), trauma (injury), fibromuscular dysplasia (twisting, narrowing or enlargement of arteries), and vasculitis (inflammation of the blood-vessels which causes them to thicken, thereby reducing blood-flow).
Symptoms include pain, discomfort and cramps in the legs or buttocks (called intermittent claudication), sores in the foot and toes that do not heal, reddish, greenish, or purplish skin, cool, smooth, and shiny skin on the feet, frequent infections of the skin and soft tissues in the legs or feet, reduced or no pulse in the feet, hair-loss in the affected leg and atrophy or muscle-loss in the affected limb.
Treating PAD
In the past, open, or incisional surgery to clear blockages or do a bypass, and medicines to overcome various conditions that are causing PAD, were the only treatment options. But in the last couple of decades, there have been various invasive, non-invasive, and new-age treatment methods to treat PAD. These methods use medication, that achieves various objectives, or, revascularization which involves clearing or bypassing the blockage and preventing its recurrence. We will examine some of them now.
- Balloon Angioplasty with Stenting – also called Percutaneous Transluminal Angioplasty: Similar to the procedure done for blockages in the heart, a catheter with a deflated balloon at its tip is threaded all the way to the spot of the blockage. The balloon is inflated which helps push the plaque against the walls of the blood vessel. Newer techniques around this procedure includes a drug-coated balloon to prevent a blockage from recurring at the spot.
- Drug-coated balloons and drug-eluting stents: As the name implies, the balloons used in balloon angioplasty are coated with certain drugs. Or the stent used can inject or push certain drugs. These drugs reduce the proclivity (tendency to attract or encourage) to plaque formation. This helps reduce the risk of new blockages recurring at that spot.
- Lithoplasty (from Shockwave Medical): This procedure is used in conjunction with balloon angioplasty. Sound waves are impinged on the spot of the blockage. The vibration from the sound waves helps break up the plaque into tiny pieces that get circulated and eventually eliminated out of the body. The angioplasty with stenting helps prevent the blockage from recurring at that spot.
- Atherectomy: Atherectomy technologies are aimed at breaking up the plaque into smaller pieces which either eliminated out of the body or become too small to cause any harm. Debulking techniques include lasering, shaving, sanding, cutting, and drilling. The choice of technique and device concerned is decided by the size of the artery. Incidentally, atherectomy can be used in conjunction with balloon angioplasty with or without stenting.
- Pantheris Lumivascular Atherectomy System (from Avinger, Inc.): Atherectomy comes with a minor drawback of the artery wall getting torn by the technique used. This drawback is overcome through a new technique called Pantheris LAS. Here, the atherectomy procedure is more precisely guided using an imaging technology called Optical Coherence Tomography. OCT produces high-resolution, 3D images of the artery and plaque formation, which guides the doctor’s movements, thereby achieving perfect and harmless atherectomy.
- Cholesterol reducing medication: Reducing low density lipoprotein cholesterol (LDLC) is known to reduce the risk and progression of cardiovascular diseases. The same learnings are borrowed in order to treat PAD. Major classes of drugs used in this therapy include statins, more recently PCSK9 inhibitors, and the drug ezetimibe.
- Anti-platelet therapy: One of the risks from atherosclerosis is that the hardened plaque can push against the artery wall and tear it. In response to this tear, platelets in the blood rush to the spot to seal off the tear. This results in a blood-clot. The downside of the blood-clot is that it can also narrow down the artery and further, it can break-away, and travel through the circulatory system and end up clogging some or the other artery in the body. To prevent this, anti-platelet medications are given to reduce platelet activity or their ability to aggregate at the spot. Such drugs include aspirin, clopidogrel and ticagrelor.
- Anti-coagulation therapy: In addition to tearing of artery walls, there are other risks for the development of blood clots. These can be dangerous in any body, and is high-risk for someone with PAD. Anti-coagulation therapy aims to reduce the formation of blood-clots and the associated risks. Drugs used for this therapy include Warfarin and Rivaroxaban.
- Peripheral Vasodilators: These drugs aim at reducing constriction of blood-vessels and increasing blood-flow, so that the risk of stroke and gangrene (in the case of PAD) are reduced. Drugs used for this therapy include cilostazol.
- Blood-Pressure Management: In patients with PAD, the recommended BP is less than 140/90. Angiotensin-Converting Enzyme (ACE) Inhibitors and Angiotensin Receptor Blockers are two classes of drugs used in this therapy.
- Smoking Cessation: Tobacco consumption is a huge risk factor for PAD. Toxins found in tobacco produce reactive oxygen species that can permeate the endothelial cells found in the walls of arteries. This encourages plaque build-up or atherosclerosis within the walls of the artery. The good news is that by quitting tobacco altogether, the build-up can be reduced. Subsequently, other therapies listed here can be used to flush out or debulk the existing plaque deposits.
- Other Medical therapies such as Pentoxifylline and Naftidrofuryl.
- Gene therapy: This involves the transfer of genetic material to specific cells in the arteries to encourage angiogenesis (development of new blood-vessels), capillary formation (this also pertains to new blood-vessel development) and collateral formation or arteriogenesis (natural development of bypasses around blockages). Specific techniques include Vascular Endothelial Growth Factor (VEGF), Regional Angiogenesis with VEGF (RAVE), Fibroblast Growth Factor, Hypoxia Inducible Factor-1α, Hepatocyte Growth Factor and Developmentally Regulated Endothelial Locus.
- Cell Therapy: Mononuclear cells derived from the bone marrow can be used to generate endothelial progenitor cells. These cells play a significant role in collateral blood-vessel formation. They also help increase capillary density, perfusion (blood-flow) and organ function.
- Adventitial Drug Delivery: The adventitia is the outer layer of the arterial walls. They are quite sturdy and can be used to store and/or deliver drugs. Accordingly, drugs that discourage the formation of plaque deposits on arterial walls can be injected or delivered to the adventitia. This will prevent the formation of new deposits and help flush out the existing deposits. Dexamethasone is the most popular drug used for the therapy.
Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai (Alwarpet & Vadapalani), Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.
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