Results from thrombus or vegetation within the heart or aorta, or paradoxically from a venous thrombus through a right-to-left intracardiac shunt.
Sudden pain or numbness in an extremity in the absence of previous history of claudication.
Absent pulse, pallor, and decreased temperature of limb distal to the occlusion. Lesion is identified by angiography.
Treatment: Arterial Embolism IV heparin is administered to prevent propagation of clot. For acute severe ischemia, immediate endovascular or surgical embolectomy is indicated. Thrombolytic therapy (e.g., tissue plasminogen activator, reteplase, or tenecteplase) may be effective for recent thrombus within atherosclerotic vessel or arterial bypass graft. |
A subset of acute arterial occlusion due to embolization of fibrin, platelets, and cholesterol debris from more proximal atheromas or aneurysm; typically occurs after intraarterial instrumentation. Depending on location, may lead to stroke, renal insufficiency, or pain and tenderness in embolized tissue. Atheroembolism to lower extremities results in blue toe syndrome, which can progress to necrosis and gangrene. Treatment is supportive; for recurrent episodes, surgical intervention in the proximal atherosclerotic vessel or aneurysm may be required.
Manifest by Raynaud's phenomenon in which cold exposure results in triphasic color response: blanching of the fingers, followed by cyanosis, then rubor. Usually a benign disorder. However, suspect an underlying disease (Table 126-1) if tissue necrosis occurs, if disease is unilateral, or if it develops after age 50.
Treatment: Vasospastic Disorders Keep extremities warm. Tobacco use is contraindicated. Dihydropyridine calcium channel blockers (e.g., nifedipine XL 30-90 mg PO qd) or α1-adrenergic antagonists (e.g., prazosin 1-5 mg tid) may be effective. Phosphodiesterase-5 inhibitors (e.g., sildenafil) may improve symptoms in secondary Raynaud's phenomenon. |
Thromboangiitis Obliterans (Buerger's Disease) 
Occurs in young men who are heavy smokers and involves both upper and lower extremities; nonatheromatous inflammatory reaction develops in veins and small arteries, leading to superficial thrombophlebitis and arterial obstruction with ulceration or gangrene of digits. Imaging with CT, MR, or conventional angiography shows smooth tapering lesions in distal vessels, often without proximal atherosclerotic disease. Abstinence from tobacco is essential.
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