UFS Peripheral Arterial Disease A problem of supply and demand Larry Rhoads, Associate Chief Underwriter November 8, 2011
PAD Two categories of these circulation disorders: Functional peripheral vascular diseases don't have an organic cause. They do not involve defects in blood vessels' structure. They're usually short-term effects related to "spasm" that may come and go. Raynaud's disease is an example. It can be triggered by cold temperatures, emotional stress, working with vibrating machinery or smoking. Organic peripheral vascular diseases are caused by structural changes in the blood vessels, such as inflammation and tissue damage. Peripheral artery disease is an example of an organic PVD, caused by fatty buildups (atherosclerosis) in arteries typically in the arteries that carry blood to the legs.
Why do we care? Lower-extremity peripheral arterial disease (PAD) is common, affecting up to 12% to 29% of the elderly and as many as 8 million Americans Intermittent claudication, the most frequent symptom of PAD, impairs quality of life and functional status Individuals with PAD suffer a 5-fold-increased relative risk of a heart attack and 2- to 3-foldgreater risk of stroke and total mortality than those without PAD People with PAD suffer combined annual rates of heart attack, stroke, and hospitalization that are comparable to or greater than rates observed in individuals with established coronary artery disease or stroke The prevalence of PAD is expected to increase as the population ages
Risk factors for PAD compared 7.01 6.01 5.01 # times more likely to have PAD 4.01 3.01 2.01 1.01 0.01 Smoking HTN CRI Diabetes Smoking Diabetic
But Does having PAD really increase the risk of CAD death that much? PAD, symptomatic or asymptomatic, is a powerful independent predictor of CAD and CVD PAD severity ABI Mortality Rate / CAD Death (10 year) None WNL 11% (Vasc. Med. 3, 241, 1998) Mild to Moderate 0.9-0.6 40% Moderate to Severe < 0.6 60%
It s not only CAD death Some facts about amputation Uncorrected PAD, especially in diabetics, may eventually cause CLI - critical limb ischemia Involves non-healing ulceration or gangrene of the foot or toes. Threatened limb loss or tissue loss CLI causes persistently recurring rest pain requiring regular analgesia The risk of leg amputation is 15-40 times greater for a person with diabetes International Diabetes Federation estimates that somewhere in the world, a leg is lost to diabetes every 30 seconds 40% of amputees die within 2 years, in some studies average survival following a diagnosis of CLI is 1 year
Why are diabetics at greater risk for PAD and CAD? A high concentration of glucose irritates and inflames the artery walls, promoting the formation of plaque (this is a macrovascular complication of diabetes) This plaque itself also causes more inflammation of the inner lining of the arteries when the immune system gets involved, a vicious circle Diabetics have higher levels of a certain type of blood fat (triglycerides) which makes up apolipoprotein E this substance probably contributes to the atherosclerotic process Hyperglycemia changes LDL cholesterol into a much more dangerous substance (glycated LDL) by making it more vulnerable to oxidation. Free radicals react with this changed LDL and make it much more likely to form plaques Endothelial dysfunction seems to be the underlying issue which allows these factors to form atherosclerosis (more on this next)
Introducing the endothelium Endothelium is an organ an amazing organ which forms one continous single layer of cells lining the entire circulatory system, from the heart to the smallest capillary It creates, stores, releases and uptakes vasoactive substances which play a role in many phenomena: Formation of new blood vessels (angiogenesis) Vasoconstriction and vasodilation, (blood pressure control) Blood clotting (thrombosis and fibrinolysis) Atherosclerosis Inflammation and swelling
Endothelial dysfunction - the culprit in many conditions Endothelial cells release nitric oxide (not laughing gas) that controls vascular relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet adhesion. Endothelial dysfunction has been shown to predict stroke and heart attacks The dysfunction may be a result of high blood pressure, diabetes, high cholesterol, sleep apnea, smoking and other factors Endothelial dysfunction may cause or contribute to: hypertension, CAD, MI, stroke, PAD, OSA, preeclampsia, raynaud's disease, diabetes, renal failure, stroke, dementia, memory loss, vision loss, erectile dysfunction
Are there blood tests for epithelial dysfunction? Yes and no there are some tests, but they are not yet ready for prime time: Soluble vascular cell adhesion molecule (svcam-1) Soluble intercellular adhesion molecule 1 (sicam-1) Tumor necrosis factor alpha (TNF-α) Homocysteine Soluble E-selectin (se-selectin) von Willebrand factor (vwf)
Vascular Tests Diagnosis of PAD Non-invasive techniques ABI (Ankle/Brachial Index) Exercise Test Leg angina Segmental Pressures Segmental Volume Plethysmography Duplex Ultrasonography Same test done on carotids Invasive techniques Peripheral Angiograms CT Angiograms MR Angiograms Segmental pressures with Doppler velocity Pressures are measured at high thigh, above knee, below knee and ankle levels. A plethysmograph is an instrument for measuring changes in volume within an organ or whole body (usually resulting from fluctuations in the amount of blood or air it contains).
The first Test Done to Assess PAD - Physical Exam Physical exam touch and sight: Is the foot and lower leg cool to the touch? Are pulses palpable on the top of the foot (dorsalis pedis) or behind the ankle joint (posterior tibialis)? Is the skin of the lower leg discolored in comparison to the upper leg? Is there rubor (darkening) of the skin when feet are hanging down and pallor (blanching or lightening) of the skin when raised over the level of the heart? Is the skin shiny and tight looking without normal hair growth? Is touch sensation normal or diminished? Any non-healing ulcers?
Normally, blood pressure is the same at the ankle or slightly higher at the ankle than at the brachial artery (in the arm). So if the pressure at the arm were 120 and the pressure at the ankle 130, this is a normal measurement. The ABI in this case would be 1.08 (130 divided by 120) When the pressure at the ankle level is significantly less than the brachial pressure (0.8 or less) PAD exists. What if the pressure is considerably higher at the ankle than at the arm? For example, if the arm were 120 mm/hg and the ankle 160? This is an ABI of 1.33 which is higher than normal. What could account for this? Diabetics may have high ABI s due to calcification or hardening of the arteries. This causes increased pressure and may mask true PAD. In diabetics, other tests in addition to ABI measurement may be needed if there is suspicion for PAD
Prevention of PAD Quit smoking Smoking constricts blood vessels, also makes blood clot easier Optimal control of diabetes Already talked about how hyperglycemia causes plaque formation Optimal control of hypertension HBP damages the lining of arteries, leads to plaque formation Optimal control of cholesterol, especially LDL Exercise Conditions muscles to use oxygen more efficiently Diet high in fiber and antioxidants Diets rich in nutrients such as vitamins A, B-6, C and E; folate; fiber; and omega-3 fatty acids are associated with a lower incidence of peripheral artery disease
Signs and Symptoms of PAD At least half of the people with PAD have no symptoms often because they have ceased doing things that cause the pain to come on (like walking briskly, climbing stairs, etc) Marked decrease in temperature of the foot or lower leg Weak or absent pulses Pale or bluish color to the feet and lower legs Erectile dysfunction Most common symptom is a painful muscle cramping when walking, climbing stairs or exercising ( claudication ). This happens in the hips, buttocks, thighs and calves (depends on where the narrowing occurs). Like typical angina, it is worse with exercise and goes away when resting. Non-healing sore in foot or toe
Non-Surgical Treatments for PAD Blood pressure lowering drugs Cholesterol lowering drugs Anticoagulants Daily aspirin and/or clopidogrel (Plavix) Symptom relief medications Cilostazol (Pletal), most effective Arterial vasodilator and also inhibits platelets from forming clots Pentoxifylline (Trental) Acts as arterial vasodilator
Surgical treatments for PAD Balloon Angioplasty, with or without stenting Cutting Balloon - cutting balloon catheter has a balloon tip with small blades. When the balloon is inflated, the blades are activated. The small blades score the plaque, then, the balloon compresses the fatty matter into the arterial wall. Atherectomy - procedure that uses a sharp blade to remove plaque from a blood vessel. The catheter is designed to collect the removed plaque in a chamber in the tip of the catheter, which allows removal of the plaque as the device is removed from the artery. Thrombolysis - uses drugs designed to dissolve clots and restore normal blood flow. Surgical Bypass - reroutes blood flow around the blockage using a graft (using vein or synthetic) Endarterectomy - open surgical removal of cholesterol plaque from an artery Amputation
Q&A