Current Options in the Diagnosis and Management of Acute Limb Ischemia

Karthikeshwar Kasirajan, MD, Kenneth Ouriel, MD

Disclosures

Prog Cardiovasc Nurs. 2002;17(1) 

In This Article

Etiology

Acute limb ischemia (ALI) results from a sudden obstruction in the arterial flow to the extremity due to an embolism or thrombosis. Embolic problems result in a greater degree of ischemia than thrombosis, as the embolus characteristically lodges in a "virgin" vascular bed with no prior collateral development. On the contrary, an in situ thrombosis occurs in vessels with prior, gradual atherosclerotic narrowing that has stimulated the formation of collateral channels. The presence of these collaterals lessens the severity and rapidity of symptom development when the atherosclerotic narrowing progresses to occlusion.[1] It is often difficult to distinguish an embolus from a thrombosis, but embolic occlusions should be suspected in patients with the following features: 1) acute onset, where the patient is often able to accurately time the moment of the event; 2) a history of embolism; 3) a known embolic source, such as cardiac arrhythmias; 4) no prior history of intermittent claudication; and 5) normal pulse and Doppler examination in the unaffected limb.

In addition to the presence of collateral channels, the location of the occlusion may also play a critical role in the severity of limb ischemia. For example, occlusion of the popliteal artery results in profound limb ischemia, since it is the only artery crossing at the level of the knee. By contrast, occlusion of the anterior tibial artery is often asymptomatic, as two other vessels -- the posterior tibial and peroneal arteries -- can function as alternate parallel channels to supply the foot.[1]

Due to a decline in the incidence of rheumatic heart disease, advances in cardiac surgery, and the widespread use of anticoagulation for arterial arrhythmias, generalized atherosclerosis resulting in thrombosis is the most common etiology of acute peripheral arterial occlusion. The superficial femoral artery is the most common site of atherosclerotic narrowing. In addition, aggressive use of bypass grafts has resulted in a greater number of patients presenting with acute ischemia. The ever-changing nature and increasing complexity of the vascular pathology requires a multimodality approach that may involve vascular surgeons, cardiologists, radiologists, coagulation specialists, and various critical care specialists. Most importantly, this patient care team must include knowledgeable nurses and technologists who are the eyes and the ears of the physicians and provide the moment-to-moment care of this quite fragile group of patients.

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