Introduction

Abstract

Percutaneous mechanical thrombectomy (PMT) refers to a heterogeneous group of devices and techniques used to fragment, ablate, and/or extract intravascular thrombus. The last decade has witnessed a remarkable evolution of PMT from an experimental curiosity to a mainstream technique in the armamentarium of the modern interventionist. This rapid evolution was the result of a number of factors: continued innovations in device design, experimental evaluation of PMT in a growing number of applications which culminated in the approval by the Food and Drug Administration (FDA) of several devices for clinical use, prominent support from the medical device industry which saw in PMT a new avenue of sales growth and, to some extent, the relative vacuum created after the withdrawal of urokinase from the US market. While PMT is currently a well-accepted first-line modality in the treatment of clotted hemodialysis access grafts, its role in other applications is less well-defined and varies widely depending on the specific application, and institutional experience and guidelines. This issue of Techniques in Vascular and Interventional Radiology summarizes the experience of some of the leading experts in the field. The authors introduce us to the basic principles of PMT and present the current clinical status of PMT in the main potential areas of clinical applications: native arteries and bypass grafts, synthetic arteriovenous (AV) grafts, native AV fistulae, deep venous application, pulmonary embolism, as well as in TIPS and the portal venous system. With the growing experience with PMT, certain clinical trends in the use of these techniques have become somewhat evident. The role of PMT devices in clotted synthetic hemodialysis access grafts is well established. The efficacy of end-hole catheter-based aspiration thrombectomy is well established, and this simple technique will remain a highly valuable technique in the management of peripheral arterial thromboembolic occlusions. However, the use of PMT devices in peripheral arterial occlusions remains controversial, despite growing evidence for its efficacy. This is most likely because of unabated concerns for the risk of embolic complications. Current experimental evidence favors the use of ablation-evacuation devices (such as devices classified under hydrodynamic PMT) over ablation-only devices in applications where embolization is less tolerable, as in the native arterial beds. Venous applications on the other hands have been more readily explored because of the lower perceived concern with the risk of embolization. As the potential indications, strengths, and limitations of PMT continue to evolve, it is important to realize that the full, real-life potential of these techniques in clinical practice is best accomplished when used in conjunction with other adjunctive techniques, such as simple suction thrombectomy, local pharmaco-thrombolysis, percutaneous atherectomy devices, transluminal balloon dilation, and stenting. The last three can, in fact, be invaluable in managing the most resistant component of thromboembolic occlusions, due to chronic organized thrombus or underlying atherosclerotic or fibrotic tissue. Although its role remains far from being clearly defined, PMT has become an important addition to the armamentarium of physicians caring for vascular diseases. As its role becomes better understood, its indications and limitations recognized, and as clinicians become more aware of its value, PMT will undoubtedly play a major role in the future management algorithms of thrombotic occlusive disorders.