Spontaneous recanalization of arterial occlusions: An unusual mechanism for symptomatic improvement

Objective: Patients with infrainguinal occlusive disease may experience spontaneous symptomatic improvement. This is generally thought to be from augmented collateral circulation. This study reports another mechanism. Methods: Over a 20-year period, 4123 paients underwent lower extremity arteriography for limb ischemia. For a variety of reasons, 451 patients had repeat arteriography. Results: Five patients were identified as having conclusive arteriographic evidence of spontaneous recanalization of occluded arterial segments without having undergone any surgical or thrombolytic interventions. Repeat contrast arteriography was performed on these patients for failing grafts (n = 2) or contralateral lower extremity ischemia (n = 3). Three other patients had magnetic resonance arteriographic or duplex arteriographic evidence of spontaneous arterial recanalization. Spontaneous recanalizaton occurred in ileofemoral (n = 2), superficial femoral (n = 2), popliteal (n = 3), and peroneal (n = 1) arterial segments. The average time interval of occlusion to recanalization was 21 weeks (2 weeks to 2 years). Two of the eight patients had failed revascularization procedures before spontaneous recanalization. All eight patients had restoration of pulses distal to the recanalized segments and significant symptomatic improvement as defined with the Society for Vascular Surgery/American Association for Vascular Surgery categories for limb ischemia. Conclusion: Spontaneous recanalization of arterial segments can occur and must be considered when evaluating other proposed treatments of critical limb ischemia, including cilostazol, lytic agents, and angiogenic agents, such as vascular endothelial growth factor. Although its true incidence is unknown, this represents another mechanism for spontaneous symptomatic improvement without treatment in patients with severe limb ischemia.