|
|
Sheldon Gottlieb, M.D.
02-04-2011
- Peripheral vascular disease (PVD) includes disorders of the blood vessels (arteries and veins) outside the heart and brain. Persons with diabetes are especially at risk for ischemia in arteries of the legs and feet, termed "lower extremity peripheral artery disease (PAD)".
- Claudication is defined as limb pain with activity. It is due to muscle ischemia caused by arterial insufficiency.
- Critical Leg Ischemia (CLI) is defined as rest pain, ulcerations, or gangrene, with expectation of threatened limb loss within 6 months.
- "Diabetic Foot Syndrome" includes the combined effect of vascular and neuropathic (foot ulcer) injuries that lead to lower-extremity amputations (Bild).
- Major cause of PAD is atherosclerosis but many conditions, including venous insufficiency, mimic symptoms of PAD -- these are called "pseudoclaudication"; see "differential diagnosis" below.
- Exponential increase in prevalence of PAD with age in the general population, up to 60% in 85 years and older in white Europeans, little data in other populations (Bennett)
- In <50 years old, PAD almost always due to diabetes plus another risk factor for atherosclerosis (smoking, lipids, hypertension).
- Prevalence of PAD among all persons with diabetes is 20-30% but much higher among persons with diabetes who are smokers (Marso).
- Poor-fitting footwear is thought to be major cause of amputation in PAD (Hennis).
- Mortality of persons with PAD is high, and after any lower extremity amputation mortality is very high, up to 80 percent in 5 years (Hambleton).
- Risk ratio for diabetes and PAD is 15:1 (i.e. persons with diabetes are 15 times more likely to develop PAD than persons without diabetes (Bild). [In comparison, risk ratio for smoking and lung cancer is about 10:1.]
-
History: Suspect in persons age < 70 with risk factors of smoking or diabetes, or age >70, and symptoms of reduced physical functioning.
- Differential diagnosis (DDX) includes mechanical causes of nerve root irritation, arthritic and inflammatory causes, aneurysm or Baker's cyst causing leg pain, and chronic compartment syndromes. See table 2 below for DDX and diagnostic clues.
-
Ankle brachial index (ABI): key test, done on all persons with PAD to assess severity and to establish a baseline. ABI <0.9 is 95% sensitive for detecting PAD and nearly 100% specific for excluding healthy persons. ABI <0.5 associated with very poor 5 year survival. See Grenon for instructions on how to perform ABI, and Marso for diagnostic algorithm.
- ABI may be normal at rest due to collateral flow; exercise ABI also an important test (Grenon, Marso). ABI >1.0 in diabetes often due to calcified non-compressible leg vessels.
- When CLI is present, the location and severity of vascular lesions must be determined, as well as hemodynamic requirements for successful revascularization and assessment of risk of endovascular and surgical repair.
-
Duplex ultrasound: determines location and severity of obstruction.
-
Contrast angiography: used when revascularization is contemplated, with caution considering renal status.
- See table 2 for complete list of diagnostic tests useful for evaluation and management of persons with PAD.
- Classification of PAD signs and symptoms include: Fontaine's Stages and Rutherford's "Categories" (see table 1 below), ranging from asymptomatic to ulceration or gangrene.
- Claudication is intermittent and reproducibly associated with activity such as walking. Quantitate by distance or time (how many feet or blocks before pain? Claudication has low sensitivity but high specificity for PAD (Marso).
- Differentiate ischemic, neuropathic and venous leg and foot ulcers: ischemic ulcers are intensely painful; neuropathic ulcers are painless and located at pressure points of the feet or ankle; enous ulcers are mildly painful. See table 2 below.
- CLI is a medical/surgical emergency; urgent evaluation and revascularization may be necessary to avoid high likelihood of amputation within 6 months (see Hirsch table 5).
- Smoking cessation essential for all persons with PAD.
- Proper foot care, including appropriate footwear and podiatric care is essential (Hirsch).
- Supervised exercise treatment, 30 - 45 minutes, 3 times a week for minimum of 12 weeks recommended and can be more effective than drug therapies. See Hirsch table 17 for key elements of PAD exercise rehabilitation program.
-
Blood pressure treatment goals are <130/80 mm Hg in people with diabetes. Beta blockers are not contraindicated in PAD (Hirsch).
- Treat with statins for goal LDL <70 mg/dl (Hirsch, McDermott). Beneficial effect of statins to improve function may be independent of lipid-lowering (McDermott).
- Use antiplatelet and other antithrombotic drugs for severe PAD and known cardiovascular disease (Sobel). Aspirin 75-325 mg daily is recommended for patients with PAD to reduce both cardiac and stroke morbidity and mortality. Clopidogrel may be used in aspirin intolerant patients. Primary benefit of these drugs may be to reduce incidence of stroke (McDermott).
- The evidence for benefit of glucose control in management of PAD is scant.
- Cilostazol recommended only for patients with disabling symptoms of claudication who are not candidates for revascularization (Sobel). Pentoxifylline is not effective (Marso).
- Surgical treatment indicated if symptoms of PAD are disabling, unresponsive to smoking cessation, exercise and medications (Hirsch).
- Work with the patient to: achieve goals of smoking cessation, titrate medications for blood pressure and lipids, improve ability to walk, and avoid CLI and lower extremity amputation.
- Specific recommendations for frequency of follow-up are individualized.
- For most patients with diabetes, examination of the feet will yield useful information and is an essential part of the physical examination.
- Patients with diabetes must be taught how to inspect their feet.
- Any patient with diabetes and history of cigarette smoking likely has PAD. Symptoms should be assessed during routine visits.
- Berger JS, Krantz MJ, Kittelson JM, et al.;
Aspirin for the prevention of cardiovascular events in patients with peripheral artery disease: a meta-analysis of randomized trials.;
JAMA;
2009; Vol.
301; pp.
1909-19;
ISSN:
1538-3598;
PUBMED: 19436018
Rating:
Basis for recommendation
Comments:Aspirin reduced non-fatal strokes but not cardiovascular events. Despite meta-analysis, statistical power remains lacking.
- Momsen AH, Jensen MB, Norager CB, et al.;
Drug therapy for improving walking distance in intermittent claudication: a systematic review and meta-analysis of robust randomised controlled studies.;
Eur J Vasc Endovasc Surg;
2009; Vol.
38; pp.
463-74;
ISSN:
1532-2165;
PUBMED: 19586783
Rating:
Basis for recommendation
Comments:Excellent review of drug therapy for PAD symptoms.
- Sobel M, Verhaeghe R, American College of Chest Physicians, et al.;
Antithrombotic therapy for peripheral artery occlusive disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).;
Chest;
2008; Vol.
133; pp.
815S-843S;
ISSN:
0012-3692;
PUBMED: 18574279
Rating:
Basis for recommendation
Comments:Evidence-based clinical practice guideline from the American College of Chest Physicians.
- Hirsch AT, Haskal ZJ, Hertzer NR, et al.;
ACC/AHA 2005 Practice Guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report. ;
Circulation;
2006; Vol.
113; pp.
e463-654;
ISSN:
1524-4539;
PUBMED: 16549646
Rating:
Basis for recommendation
Comments: Complete on-line text book of PAD
|
|
