SFA: Do we need to Protect it?

Abstract

The article of Czihal et al. suggests the full use of embolic protection device (EPD) during endovascular interventions in the superficial femoral artery (SFA) [1]. EPD has become the standard of care in some centers, in both carotid and saphenous vein coronary bypass graft interventions after successful outcomes in these vascular territories. However, a scientific evidence is still not available. It is well known and described that up to 5% of all endovascular treatments of the SFA are complicated by clinically significant distal embolization mostly visualized at angiography [2]. Only the use of atherectomy has been demonstrated to be associated with a higher risk of distal embolic complications. Lam et al. had previously studied the incidence and clinical significance of distal embolization during percutaneous interventions involving the SFA in 60 patients. They had used continuous Doppler ultrasound monitoring and found embolic signals in all phases of SFA interventions [3]. However, there is not a general consensus on the definition of clinically significant distal embolization during peripheral interventions. The PROTECT (Preventing Lower Extremity Distal Embolization Using Embolic Filter Protection) registry was dedicated to this topic, but only 40 patients were enrolled, and having no group to compare made deriving conclusions difficult [4]. For all these reasons, the role of EPD during SFA interventions has not yet been clearly established and no guidelines either support or recommend the use of EPD during lower extremity revascularization. Unfortunately, the article [1] is not helpful either because the population is not homogeneous and there is a chaotic mix of different types of lesions from the chronic, more stable, to the acute ones or pretty unstable. Moreover, different treatment strategies from simple balloon angioplasty to complex combine treatment (atherectomy plus angioplasty plus stenting) have been used without specific correlation with the lesion morphology. As a consequence, it is clear that no valid conclusions can be reached and even though the work is excellent, there were no scientifically interesting results produced. In addition, the authors Czihal et al. [1] present their own, angiography-based method to find out the presence of macroscopic material inside the filter, but their investigation is not sustained by a microscopic analysis and laboratory tests necessary for a histopathological evaluation. Consequently, the question whether the macroscopic material is based on plaque debris or simple thrombus remains unclear. We have learned from different publications that when the filter permanence inside a vessel lasts for a long time— as it happens during the treatment of peripheral lesions— the formation of a thrombus is significantly stimulated, an event extremely rare when no filter is present inside a vessel. This is probably the reason why the authors reported on such a high percentage of distal embolization even though a filter is employed. For example, Wasty et al. provided information about the composition of debris captured within EPD by comparing it with debris captured in the nosecone of the SilverHawk atherectomy device during SFA interventions. They found that the embolized debris differed significantly & Fabrizio Fanelli [email protected]