Recommendations for Revascularization for ALI
COR	LOE	Recommendations
I	C-LD	In patients with ALI, the revascularization strategy should be determined by local resources and patient factors (eg, etiology and degree of ischemia).367–369
See Online Data Supplement 47.		For marginally or immediately threatened limbs (Category IIa and IIb ALI [Figure 3]), revascularization should be performed emergently (within 6 hours). For viable limbs (Category I ALI [Figure 3]), revascularization should be performed an on urgent basis (within 6–24 hours). The revascularization strategy can range from catheter-directed thrombolysis to surgical thromboembolectomy. Available facilities and clinical expertise are factors that should be considered when determining the revascularization strategy. The technique that will provide the most rapid restoration of arterial flow with the least risk to the patient should be selected. For example, catheter-directed thrombolysis can provide rapid restoration of arterial flow to a viable or marginally threatened limb, particularly in the setting of recent occlusion, thrombosis of synthetic grafts, and stent thrombosis.367 If this is not available locally, surgical options for timely revascularization should be considered, along with the feasibility of timely transfer to a facility with the necessary expertise.
I	A	Catheter-based thrombolysis is effective for patients with ALI and a salvageable limb.367–371
See Online Data Supplement 47.		Assessment of the comparative effectiveness of catheter-based thrombolysis versus open surgery is complicated by variable definitions of ALI in this literature. Four RCTs comparing catheter-based thrombolysis to surgery,367,369–371 as well as a meta-analysis,368 have demonstrated similar limb salvage rates between the 2 approaches but better survival with catheter-based therapy. The survival advantage of catheter-based therapy may be at least in part attributable to multiple comorbidities found among the population of patients who present with ALI. Increased comorbidities are likely to contribute to increased perioperative risk. Several of the RCTs included patients with relatively chronic ischemia. Acuity and severity are both factors in the decision to consider thrombolysis.367,369–371
I	C-LD	Amputation should be performed as the first procedure in patients with a nonsalvageable limb.372,373
See Online Data Supplement 48.		For patients with Category III ALI (Figure 3), amputation should be performed as the index procedure. Prolonged duration of ischemia is the most common factor in patients requiring amputation for treatment of ALI. The risks associated with reconstruction outweigh the potential benefit in a limb that is already insensate or immobile because of prolonged ischemia. Patients who have an insensate and immobile limb in the setting of prolonged ischemia (>6 to 8 hours) are unlikely to have potential for limb salvage.34,362 In addition, in this setting the reperfusion and circulation of ischemic metabolites can result in multiorgan failure and cardiovascular collapse. However, if pain can be controlled and there is no evidence of infection, amputation may be deferred if this meets with the patient's goals.
I	C-LD	Patients with ALI should be monitored and treated (eg, fasciotomy) for compartment syndrome after revascularization.372,373
See Online Data Supplement 48.		The lower extremity muscles reside in compartments, surrounded by fascia and bones. Reperfusion to ischemic muscles can cause cellular edema, resulting in increased compartment pressure. When compartment pressure is >30 mm Hg, there is capillary and venule compression that leads to malperfusion of the muscle; this is compartment syndrome. Fasciotomy is indicated when the compartment pressure increases. Measurement of intracompartment pressure is not always easily accessible. In such cases, evaluation for fasciotomy is prompted by development of increased pain, tense muscle, or nerve injury. Fasciotomy should be considered for patients with Category IIb ischemia for whom the time to revascularization is >4 hours.
IIa	B-NR	In patients with ALI with a salvageable limb, percutaneous mechanical thrombectomy can be useful as adjunctive therapy to thrombolysis.374–378
See Online Data Supplements 49 and 50.		Multiple nonrandomized studies have suggested that percutaneous mechanical thrombectomy in combination with pharmacological therapy can be beneficial in the treatment of threatened limbs.374–378
IIa	C-LD	In patients with ALI due to embolism and with a salvageable limb, surgical thromboembolectomy can be effective.379–381
See Online Data Supplements 49 and 50.		Patients with arterial embolism and an absent pulse ipsilateral to the ischemic limb can be treated by exposure of an artery in the affected limb and balloon-catheter thromboembolectomy. These patients may benefit from adjunctive intraoperative fibrinolytics. In the event that thromboembolectomy does not restore arterial flow, bypass can be performed.381–383
IIb	C-LD	The usefulness of ultrasound-accelerated catheter-based thrombolysis for patients with ALI with a salvageable limb is unknown.384–386
See Online Data Supplements 47 and 50.		The use of ultrasound-accelerated catheter delivery of thrombolytic agents has been published in case series384 and retrospective analyses.385 However, the single RCT comparing this technique to standard catheter-based thrombolytic therapy failed to demonstrate a difference in outcomes, including bleeding, despite a lower total amount of lytic delivered.386