Lower_Extremity_Vascular_Disease

Lower_Extremity_Vascular_Disease - Lower Extremity Lower...

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Unformatted text preview: Lower Extremity Lower Extremity Vascular Disease Vic V. Vernenkar, D.O. St. Barnabas Hospital Dept. of Surgery Anatomy Anatomy Anatomy Anatomy Pathophysiology Pathophysiology Most predominant cause is atherosclerotic disease Other causes include antiphospholipid syndrome, popliteal aneurysms, adventitial cystic disease, popliteal artery entrapment, and trauma. Pathophysiology Pathophysiology Collateral circulation allows for blood flow to all areas of the lower extremity in the face of localized occlusive disease Muscle arterial resistance can be decreased to allow a large increase in blood flow. This is physiologic during exercise and compensatory during ischemia As occlusive disease progresses, it usually involves multiple sites in the lower extremity vasculature Pathophysiology Pathophysiology The first symptoms are noted by the patient during exercise because the leg is no longer able to increase blood delivery in the normal fashion Claudication, is reproducible lower extremity muscle pain on walking that is relieved by rest Most commonly, it involves the calf. Pathophysiology Pathophysiology As ischemia progresses, pain is encountered at rest. With critical ischemia, the patient experiences rest pain and wounds are unable to heal, so that the patient is predisposed to infection, gangrene, and limb loss Pathophysiology Pathophysiology Rest pain initially begins in the forefoot (metatarsalgia) and toes and progresses proximally. Patients often notice a beneficial effect of gravity on their arterial blood flow. Pathophysiology Pathophysiology Many let their legs hang over the side of the bed in a dependent fashion to increase the effect of gravity, which augments minimal perfusion and decreases pain. Conversely, symptoms of rest pain are provoked and worsened when the extremity is elevated Risk Factors Risk Factors Diabetes Smoking #1 preventable cause HTN Genetics Obesity Hyperlipidemia Hypercholesterolemia Patient Evaluation Patient Evaluation History of pain (type, location position) Non­healing ulcer, infection Past medical history of diabetes, HTN, cardiac, hypercholesterolemia, hypercoagulable states Social history (smoking, activity level) Family history Physical Exam Physical Exam Full vascular examination Appearance (color, hair, muscle, nails, skin) Touch (temp, refill, tenderness, elevation) Pulses Stethoscope Neck, Abdomen Heart Non­invasive Techniques Non­invasive Techniques Ankle­Brachial Index Useful in predicting the likelihood of wound healing Amputations healed in all patients with an ABI above 70% Healing did not occur in 25% of those with an ABI below 70% Non­invasive Techniques Non­invasive Techniques Simple and inexpensive In diabetics is often unreliable because of abnormal wall calcification and noncompressibility Additional information can be obtained by measuring pressures at various levels of the lower extremity Gradients of more than 20 mm Hg are diagnostic of a hemodynamically significant lesion Duplex Ultrasound Exercise stress test can be performed Invasive Techniques Invasive Techniques Angiography is the gold standard for evaluating lower extremity ischemic disease Done before OR for precision From aorta to feet Invasive Techniques Invasive Techniques Hemodynamically significant lesions are identified by a reduction in the cross­ sectional area of 75% or more or a 50% decrease in diameter Dye load a problem for renal patients, anaphylaxis (<3%), local and distal complications (<1­2%) Not done if no intervention planned! Treatment Treatment Claudication or limb threatening? When limb­threatening, intervention is necessary Claudication lifestyle limiting? Co­existing problems, high or good risk patient? Surgery or endovascular? Conservative Conservative Stop smoking Walk Preventative foot care in diabetics Control of blood glucose level Decrease cholesterol levels Drug therapy Drugs Drugs Pentoxyphyllin (Trental), a hemorrheologic drug Increases blood filtration and decreases platelet aggregation and plasma fibrinogen Drugs Drugs Decrease in viscosity Increases blood flow in the lower extremity and increases muscle oxygen tension Drugs Drugs Cilostazol (Pletal), a phosphodiesterase inhibitor that suppresses platelet aggregation and acts as a direct vasodilator Ticlopidine, an adenosine diphosphate inhibitor, also decreases blood viscosity Endovascular Therapy Endovascular Therapy Discrete lesions of the superficial and deep femoral arteries have been successfully treated with percutaneous transluminal angioplasty Balloon causes the atherosclerotic intima to rupture and stretches the media Increased blood flow allows for continued patency Endovascular Therapy Endovascular Therapy The atherosclerotic lesion can also re­form over time Best results are observed in those with short focal lesions Success rates are higher in larger vessels Endovascular Therapy Endovascular Therapy Good runoff is important for patency Distal disease increases the risk for restenosis and failure, and the consequences would be devastating if acute thrombosis were to occur during the procedure. Endovascular Therapy Endovascular Therapy PTA has also been used successfully as an adjunct to surgery to improve inflow for a more distal bypass and outflow for a more proximal bypass Stenosis in bypass grafts is also amenable to PTA In the event of acute lower extremity ischemia, an immediate angiogram is optimal and fibrinolytic therapy may be warranted Catheter is inserted into the clot and the fibrinolytic agent is infused into the clot during the ensuing hours along with heparin. Surgical Therapy Surgical Therapy Surgical Therapy Surgical Therapy Optimize other medical problems Debride and treat infections Angiogram Surgical Therapy Surgical Therapy Endarterectomy, bypass, amputation Bypass is indicated for the patient with critical ischemia and, in specific instances, the patient with claudication Surgical Therapy Surgical Therapy Both the physician and the patient must be certain that the disease is truly incapacitating and limits the activities of daily living That conservative and medical management have been unsuccessful, and that the mortality risk and threat of limb loss as a complication of surgery are worth the possible relief of symptoms Remember! claudication progresses to critical ischemia and limb loss in relatively few cases All interventions in the peripheral circulation can be complicated by limb loss! Surgical Therapy Surgical Therapy Inflow and outflow vessels Runoff Vein (reversed or in­situ) Graft Complications Complications Perioperative mortality has been reported to be between 2% and 5% Perioperative myocardial infarction rates have been reported as 3% If silent and unnoticed myocardial infarctions are included, they may be as high as 10% to 15% Hemorrhage, hematoma, thrombosis, infection, and edema Primary amputation (when?) ...
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This note was uploaded on 12/27/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

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