[Thrombosis in Hemodialysis Tunnelled Central Venous Catheters: From Pathogenesis to Therapeutic Strategies].

Central venous catheter-related thrombosis is a frequent non-infectious complication, typically associated with catheter dysfunction and hemodialysis inadequacy. Central venous catheters (CVCs) are categorized into non-tunnelled and tunnelled types, wherein the choice depends on patient's clinical conditions and the diagnostic and therapeutic workup. Tunnelled CVCs (tCVCs) are sought whenever an arteriovenous fistula is unfeasible or as primary access in patients with poor prognosis. Dysfunction is defined as the inability to maintain adequate blood flow within the prescribed dialytic session. Amongst non-infectious complications causing tCVC malfunctioning, thrombosis is the most frequent, and it is further classified into intrinsic (being endoluminal, pericatheter or fibrin sleeve-associated thrombosis) and extrinsic forms (including mural and atrial thrombosis). Diagnosis requires imaging tests like chest X-ray or abdominal X-ray, echocardiography, dynamic catheterography and computed tomography. Pharmacological treatment involves use of local thrombolytic agents. In case of extrinsic thrombosis, systemic anticoagulation is mandatory, occasionally requiring tCVC replacement. Prevention of thrombotic complications includes adequate positioning and appropriate use of the tCVC, with anticoagulant/antimicrobial-based locking solutions playing a crucial role in this context. In cases of extrinsic thrombosis, treatment options vary based on thrombus size, ranging from a conservative approach availing of systemic anticoagulation to surgical interventions like thrombectomy or thrombus aspiration, possibly associated with tCVC removal. In conclusion, late dysfunction of tCVCs is primarily due to thrombosis, thus requiring diagnostic imaging and specific drug therapies. Prevention is crucial to minimize complications.