FEATURED TECHNOLOGY: INDIGO SYSTEm

Existing endovascular options for lower extremity and visceral arterial thromboembolism face the challenges of limited trackability, vessel injury, and incomplete revascularization. At the forefront of advances in catheter materials and technology, Penumbra, Inc. recently introduced the IndigoTM System for mechanical thrombectomy in the periphery. The Indigo System is designed to address the limitations of conventional technology, bringing greater trackability and the power of large-bore catheters and the Indigo pump to the peripheral vasculature. Lower extremity arterial thromboembolism or vessel thrombosis are major concerns, as they can block blood flow to the limbs.1 This blockage can lead to acute and subacute limb ischemia.2 Sudden loss or a decrease in limb perfusion that threatens limb sustainability carries a high threat of mortality (15%–20% 1-year mortality rate) and limb amputation (10%–15% in-hospital amputation rate) despite existing methods of treatment.2 With advances in endovascular techniques, including atherectomy and the greater use of stents and stent grafts in the peripheral arterial circulation, the chance of device occlusion/thrombosis or embolization during such procedures has greatly amplified. Atherectomy is associated with a substantial rate of distal embolization.3 Rapid revascularization is critical to diminishing the patient’s risk of long-term injury, amputation, or death when devices fail or runoff vessels are occluded during procedures. Although thrombolysis and surgical embolectomy are established therapies for these events, percutaneous devices are now available for the mechanical extraction of thrombus and distal emboli. These devices, such as the Penumbra Indigo System, are playing a larger role in the treatment of acute limb ischemia and in the rapid removal of atheroemboli when they occur during procedures.1 In January 2008, the Penumbra System® became available in the United States for the revascularization of occluded intracranial vessels in patients with acute ischemic stroke. The Penumbra System used vacuum aspiration as its primary mechanism of action. A flexible, large-bore catheter was delivered to the site of occlusion, and aspiration was directly applied to the lesion itself. To maintain lumen patency of the large-bore catheter, a Penumbra SeparatorTM was used at the tip of the catheter to continually break up the clot once ingested under aspiration. The Separator allowed continuous thrombectomy under constant aspiration supplied by an external vacuum pump. Penumbra’s latest innovation in stroke is the ACETM device, which has demonstrated high rates of complete revascularization and has made Penumbra the market leader in stroke. Recognizing the utility of this device, operators that were familiar with the Penumbra System for stroke care started using it in the peripheral vasculature for acute thrombotic and embolic events. This enabled physicians to treat lesions that were previously inaccessible with conventional technology. In 2014, Penumbra launched the Indigo System specifically for this application, redefining below-the-knee mechanical thrombectomy. The Indigo System enables the removal of emboli and thrombi from vessels of the peripheral arterial system. Unlike thrombolysis, which often requires prolonged infusion times, Indigo is able to provide rapid restoration of flow to thrombosed vessels. It can also be used for revascularization when thrombolytic therapy and surgery are contraindicated. This is achieved by utilizing Penumbra’s proprietary catheter-tracking technology and patented Separator technology for mechanical clot engagement. This 6 F–compatible percutaneous system is available in 6-F and 4-F catheter options with 132to 150-cm catheter lengths. Indigo has the largest extraction lumen designed for vessels below the knee, with smaller and longer catheter options for hard-to-reach distal extremities. The following cases demonstrate rapid revascularization times (< 15 minutes) and acceptable safety profiles. IndigoTM Percutaneous Mechanical Thrombectomy System