Filter no reflow during percutaneous coronary interventions using the Filterwire distal protection device

Area of Science:

• Interventional Cardiology
• Cardiovascular Devices
• Embolic Protection

Background:

• Distal protection devices are crucial for preventing embolization during percutaneous coronary interventions (PCI).
• The Filterwire device has been associated with a phenomenon termed Filter No Reflow (FNR), characterized by reversible flow reduction.
• FNR may be misinterpreted as true no-reflow and could impact device efficacy.

Purpose of the Study:

• To analyze the incidence and predictors of Filter No Reflow (FNR) during PCI with the Filterwire device.
• To investigate the relationship between FNR, collected debris, and angiographic findings.
• To differentiate FNR from true no-reflow and macroembolism.

Main Methods:

• A cohort of 58 patients (60 lesions) at high risk for embolization undergoing PCI of saphenous vein grafts (SVG) or native arteries (NV) with the Filterwire device was analyzed.
• Qualitative and quantitative angiographic analysis was performed.
• The volume of collected debris was estimated using a photographic technique.

Main Results:

• Filter No Reflow (FNR) occurred in approximately one-third of cases and was associated with visible filling defects within the filter basket, suggesting macroembolism.
• FNR showed a significant correlation with a higher volume of collected debris (36.97 mm³ vs. 11.31 mm³).
• The presence of FNR was not predicted by abciximab use, high thrombotic burden, increased stent volume, or need for predilatation; correlation with debris was only clear in the macroembolization group.

Conclusions:

• Filter No Reflow (FNR) is a common, reversible angiographic complication associated with the Filterwire device during PCI.
• Interventionalists should be aware of FNR and manage reduced flow conservatively.
• Both mechanical filter obstruction and other mechanisms, potentially involving debris or platelet aggregates, contribute to FNR.