The Kidney Disease Outcomes and Quality Initiative guidelines on vascular access recommend placement of an AVG only when the patient requiring hemodialysis has no suitable vascular anatomy for placement of a fistula 4. There are no universal definitions for primary failure of an arteriovenous access, which can include early thrombosis before use, inadequate maturation, or inability to be cannulated and used for dialysis over a prolonged period of time (three or four weeks) 5. The North American Vascular Access Consortium classified primary failure of a fistula as immediate failure (within 72 hours of surgery), early dialysis suitability failure, and late dialysis suitability failure. A meta-analysis by Al-Jaishi et al. 6 including fistula studies published in the year 2000 or later reported that the overall risk of primary failure was 23%, but increased to 37% in the elderly. The primary failure rate for grafts never used was approximately 10–20% 7, 8, which was lower than that of fistulas. One study reported an incidence of immediate failure of AVGs in the upper extremity of 5.8% and in thigh grafts of 12.7% 9.
In our patient, graft thrombosis occurred within 24 hours following placement. The time frame included in the definition of early thrombosis ranged from 18 days to 12 weeks postoperatively. Early thrombosis is an infrequent cause of primary failure. Neointimal hyperplasia within the AV graft creates stenotic lesions resulting in decreased blood flow. This decreased flow causes activation of blood coagulation and a hypercoagulable state (components of the Virchow triad) which eventually cause thrombosis, most often resulting in juxta-anastomotic stenosis 5. Systemic factors such as hypotension, higher hemoglobin, and hypercoagulability increase the risk of graft thrombosis 5,10. Risk factors of primary failure include age ≥ 65 years, diabetes, history of coronary artery disease or peripheral vascular disease, obesity, race, and surgical factors such as extent of surgical training, the anastomosis angle, and the type of anesthesia used 11,12,13. A patient with a thrombosed AVG should be evaluated for factors predisposing to a prothrombotic state, including plasma levels of protein C, protein S, antithrombin 3, hyperhomocysteinemia, lupus anticoagulant, and antiphospholipid antibodies 14,15,16. In this case, we thought the reason for immediate failure was due to surgical technique, with the venous-graft anastomosis created restrictively and insufficiently.
Early thrombosis differs from late thrombosis, for which thrombolytic therapy is indicated. For late thrombosis, surgical thrombectomy is also an established treatment for clearance of the thrombus 17. Alternatively, endovascular intervention with angioplasty can always be considered to treat the culprit lesions and underlying stenosis 18. Surgical thrombectomy has been performed in a small number of cases when the thrombosis occurred within one month of graft construction 9. However, early thrombosis is often unsalvageable, leading to the need for creation of a new access. Correspondingly, a study reported that early occlusion (within 30 days of fistula creation) was able to undergo salvage surgery, but still had a low probability of maturation 19.
Surgical sutures are removed in the operative area of vascular access construction in the upper extremity after two weeks when the wound has healed. In our center’s clinic experience, we found that angioplasties performed three weeks after creation of AV grafts or fistulas have a 90% success rate, while those performed earlier than 3 weeks following creation are associated with vascular rupture, continued bleeding, steal syndrome, loss of dialysis vascular access or requiring open surgery. The optimal time to intervene using percutaneous angioplasty for immediate AVG failure after its creation is a topic of debate among interventionists. Inagaki et al. 20 reported the earliest successful vascular access interventional therapy for an occluded arteriovenous fistula, only 9 days after creation, and showed long-term patency. Compared with a thrombectomy, angioplasty is less invasive and results in fewer infections. In our case, there was immediate failure of the AVG which was then abandoned, and after three months we used angioplasty with ultrasound guidance to reestablish vascular access, which was used for dialysis successfully. The AVG maintained good patency for six months, which is similar to the primary patency rate of successful AVGs 21.
The success of this case can encourage interventionists not to give up quickly on AVGs for dialysis due to early dysfunction and complications following creation. It also raises the need to create standard evaluation protocol for patients with a thrombosed AVG, since treating the underlying cause of thrombosis will reduce the number of future interventions. Finally, this case suggests the need for a randomized trial to determine the appropriate time to perform percutaneous angioplasty for immediate failure of AVGs for dialysis.