Mechanical Thrombectomy Using Indigo System for the Treatment of Acute Lower Limb Venous Bypass Occlusion

Abstract

Purpose:

This case series investigates the use of the Penumbra Indigo thrombectomy system to treat acute occlusions of below-the-knee venous bypass grafts.

Materials and methods:

Between October 2019 and August 2024, a double-center prospective study was conducted on patients who experienced acute obstruction (<7 days) of their below-knee venous graft and were treated with the Indigo System for immediate thrombo-aspiration. Enrolled patients were classified by age, gender, comorbidities, Rutherford classes, and clinical stage according to the wound, ischemia, foot infection (WIfI) classification. In addition, occluded bypass features (inflow, outflow artery, and venous conduit utilized), type of distal and proximal anastomosis, and occlusion times were collected. The primary outcome was the technical success of mechanical thrombo-aspiration which was defined as a Thrombo-aspiration In Peripheral Ischemia (TIPI) 2 or 3 flow. The secondary outcome was primary patency, assisted primary patency, defined as the patency achieved with an additional endovascular or surgical procedure not in the same procedure of thrombo-aspiration, as long as occlusion of the bypass graft has not occurred, 30-day and long-term mortality, major cardiovascular events (MACEs), and serious adverse events (SAEs).

Results:

Eight patients (6 male, 75%) with a mean age of 76 years (interquartile range [IQR]=53-85 years) were treated. Technical success was achieved in all cases, with 87.5% classified as TIPI 3 and 12.5% as TIPI 2. Local (75%) or loco-regional anesthesia (25%) was used in all cases, with percutaneous access performed in most cases (75%). Additional endovascular procedures were necessary in all patients, including inflow/outflow balloon angioplasty and/or stenting (6 patients, 75%), bypass percutaneous transluminal angioplasty (PTA) (2 patients, 25%), and fibrinolysis (2%). The average procedure time was 89 minutes, with a mean hospital stay of 4.9 days. At 30 days, there was no mortality, but 1 MACE (non-ST-elevation myocardial infarction [N-STEMI]) and 2 SAEs (bleeding and major amputation) were reported. The 30-day primary patency rate was 87.5%. At a mean follow-up of 26.1 months, mortality was 12.5%, reintervention rate was 25%, with primary patency at 62.5% and assisted primary patency at 87.5%.

Conclusion:

This case series highlights the technical feasibility and the effectiveness of the Penumbra Indigo system in treating vein bypass graft occlusions, with intraoperative success rate of 100% and limb salvage rate of 87.5%.

Clinical Impact

This case series supports the use of the Penumbra Indigo thrombectomy system as a safe, feasible, and effective treatment for acute below-the-knee venous bypass graft occlusions. Rapid mechanical thrombo-aspiration achieved high technical success and favorable short- and mid-term patency rates while minimizing the need for open surgical revision. The ability to perform the procedure under local or loco-regional anesthesia is particularly advantageous in elderly or high-risk patients. These findings highlight the potential of the Indigo system as a frontline or bailout endovascular option to optimize limb salvage and procedural outcomes in complex bypass graft failure.