Translated title: Haemodialysis access by inferior vena cava catheterisation

Recent evidence suggests that the cost as well as the morbidity associated with the maintenance of hemodialysis access is increasing rapidly; currently, the cost exceeds 1 billion dollars and access related hospitalization accounts for 25% of all hospital admissions in the U.S.A. This increase in cost and morbidity has been associated with several epidemiological trends that may contribute to access failure. These include late patient referral to nephrologists and surgeons, late planning of vascular access as well as a shift from A-V fistulaes to PTFE grafts and temporary catheters, which have a higher failure rate. The reasons for this shift in the types of access is multifactorial and is not explained by changes in the co-morbidities of patients presenting to dialysis. Surgical preference and training also appear to play an important role in the large regional variation and patency rate of these PTFE grafts. We propose a program for early placement of A-V fistulae, a continuous quality improvement, multidisciplinary program to monitor access outcome, the development of new biomaterials, and a research plan to investigate pharmacological intervention to reduce development of stenosis and clinical interventions to treat those that do develop, prior to thrombosis.

The purpose of this study was to evaluate the percutaneous translumbar approach for long-term hemodialysis catheter access. Seventeen double-lumen hemodialysis catheters were placed percutaneously from the right flank to the inferior vena cava in 12 patients. Catheter placement was successful in all patients. Adequate flow rates were obtained. Seven episodes of thrombosis-related access failure occurred (0.33 episodes/100 days at risk). Two catheters were removed and five catheters were managed with urokinase infusion. Six episodes of infection occurred (0.28 episodes/100 days at risk). Four required catheter removal. Two catheters were removed after defects developed in the catheter. Five catheters were removed electively because catheter hemodialysis was discontinued. Four catheters remained in place. Cumulative patency was 52% at 6 months and 17% at 12 months. Translumbar inferior vena cava hemodialysis catheters represent a valuable alternative in cases in which traditional catheter sites have failed.

Risk factors for acute venous occlusion range from prolonged immobilization to hypercoagulability syndromes, trauma, and malignancy. The aim of this review article is to illustrate the different imaging options for the diagnosis of acute venous occlusion and to assess the value of interventional strategies for venous thrombosis treatment in an emergency setting.First, diagnosis and treatment of the most common form of venous occlusion, at the level of the lower extremities, is presented, followed by pelvic vein and inferior vena cava occlusion, mesenteric venous thrombosis, upper extremity occlusion, acute cerebral vein thrombosis, and finally acute venous occlusion of hemodialysis access.In acute venous occlusion of the lower extremity phlebography is still the reference gold standard. Presently, duplex ultrasound with manual compression is the most sensitive and specific noninvasive test. Limitations of ultrasonography include isolated distal calf vein occlusion, obesity, and patients with lower extremity edema. If sonography is nondiagnostic, venography should be considered. Magnetic resonance venography can differentiate an acute occlusion from chronic thrombus, but because of its high cost and limited availability, it is not yet used for the routine diagnosis of lower extremity venous occlusion only. Regarding interventional treatment, catheter-directed thrombolysis can be applied to dissolve thrombus in charily selected patients with symptomatic occlusion and no contraindications to therapy. Acute occlusion of the pelvic veins and the inferior vena cava, often due to extension from the femoropopliteal system, represents a major risk for pulmonary embolism. Color flow Doppler imaging is often limited owing to obesity and bowel gas. Venography has long been considered the gold standard for identifying proximal venous occlusion. Both CT scanning and MR imaging, however, can even more accurately diagnose acute pelvis vein or inferior vena cava occlusion. MRI is preferred because it is noninvasive, does not require contrast agent, carries no exposure to ionizing radiation, and is highly accurate and reproducible. Apart from catheter-directed thrombolysis, mechanical thrombectomy has proven to be a quick and safe treatment modality by enabling the recanalization of thrombotic occlusions in conjunction with minimal invasiveness and a low bleeding risk. Mechanical thrombectomy devices should only be used in conjunction with a temporary cava filter.Contrast-enhanced CT is at present considered the examination of choice for acute mesenteric vein occlusion which has mortality rates as high as 80%. Patients with proven acute mesenteric venous occlusion and contraindications to surgical therapy and no identified bleeding disposition without looming bowel ischemia or infarction are possible contenders to the less invasive percutaneous approach either by (in)direct thrombolysis or mechanical means. Ultrasonography is the primary imaging modality for the diagnosis of upper extremity thrombosis. Computed tomography and MRI are in addition helpful in diagnosing central chest vein occlusions. The interventionalist is rarely involved in the treatment of this entity. Catheter-directed thrombolysis is known to improve lysis rates. Together with balloon angioplasty good results have been obtained. If stenosis or thrombus remains after thrombolysis and angioplasty, stent placement should follow. Within the first two weeks, thrombosed dural sinus and cerebral venous vessels are typically hyperdense on CT compared with brain parenchyma; after the course of 2 weeks, the thrombus will become isodense. In MRI an axial fluid-attenuated inversion recovery sequence, an axial diffusion-weighted MRI, coronal T1-weighted spin-echo and T2-weighted turbo-spin-echo sequences, a coronal gradient-echo and a 3D phase-contrast venous angiogram should be performed. Local thrombolysis is needed only when patients have an exacerbation of clinical symptoms or imaging signs of worsening disease despite sufficient anticoagulation therapy. Acute occlusions of dialysialysis grafts and fistulae are a frequently encountered complication. Among the various methods described for acute occlusion screening, ultrasonography and MRI have been proven to be accurate and noninvasive; however, if immediate treatment can be anticipated, imaging should be performed directly by digital subtraction angiography before the percutaneous intervention. Initial percutaneous thrombectomy is very effective with success rates and patency rates comparable to those of surgical thrombectomy. A short thrombosis can be treated with balloon angioplasty alone, whereas an extensive thrombosis requires a combination of mechanical devices and/or thrombolytic agents with adjunctive balloon angioplasty.