Short summary

Patients with end-stage renal disease (ESRD) are dependent on dialysis or renal transplantation to survive. Hemodialysis is the predominant form of dialysis and a vascular access (arteriovenous fistula or graft) is the life-line of the patient. One major aim of this study is to improve prediction of arteriovenous fistula maturation since it is of significant clinical importance. Another aim is to gain more knowledge about the association of aortoiliac calcifications and the outcome after renal transplantation. 

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Rationale

The number of patients with end-stage renal disease (ESRD) who require renal replacement therapy is rapidly increasing worldwide. ESRD are caused by a variety of congenital or - more often - acquired kidney diseases with diabetes as the most common single cause. In one fifth of the patients the cause remains unknown. In Denmark, the prevalence of actively treated ESRD-patients is doubled over the last 20 years with 5068 patients treated in 2014. This is primarily because of a significant increase in patients with diabetes and elderly patients treated. The majority of these patients are dependent on dialysis as they do not have access to or are not medically suitable for a renal transplantation (renalTX). Haemodialysis (HD) is the predominant form of dialysis (78%) whereas 22% are in peritoneal dialysis (PD). The prevalence of patients transplanted is steadily increasing as well and was 2539 patients in 2014.

The incidence of ESRD in Denmark has increased dramatically since 1990 with a trend of a more stable incidence over the last years. The incidence is around 120 patients pr. million meaning 700 new patients treated in 2014.

The outcome after a renal transplantation has improved over the last decades and so has the mortality for patients receiving HD despite the greater amount of comorbidities. Though the mortality for these patients is still very high. A critical factor in the survival of dialysis patients is the surgical creating of a vascular access (VA) without which haemodialysis is impossible. The VA is the life-line of the patient. The aim of the VA is to deliver blood to the dialysis machine with sufficient flow and with a low complication rate. The VA can be a central venous catheter (CVC) - tunneled or non-tunneled, an autologous arteriovenous fistula (AVF) or an arteriovenous graft (AVG). CVCs are a potential source of bacteraemia and have been associated with increased mortality in HD-patients. The major disadvantage of the arteriovenous fistula is the high rate of primary failure . If the patient has a current need for HD and a non-functioning AVF, the patient will require a CVC with a higher risk of morbidity and mortality as a consequence. The clinical application when having a patient with a high risk of FTM could be more extensive preoperative investigations, very close postoperative monitoring and need for aggressive interventions to facilitate maturation. The standard arteriovenous graft (AVG) is not the answer as well. The patency of the graft is limited by the development of intimal hyperplasia at the venous anastomosis or the adjacent venous outflow vein which may lead to thrombosis of the graft. Standard ePTFE (expanded polytetrafluoroethylene) grafts are prone to infection as well and this often lead to abandonment of the graft. In all, we urgently need better prediction of AVF maturation and better grafts as an alternation if the probability of AVF immaturation is high or urgent access is needed.

Consequently, the major aim for this study is to improve prediction of AVF maturation. Cardiovascular disease is a major cause of death among patients with ESRD and vascular and valvular calcifications are highly prevalent in the HD-population. Another aim of this study is to gain more knowledge about the calcifications in the aortoiliac arteries and the prognostic information that may be hidden in the CT scan done prior to the renal transplantation. 

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Description of the cohort

The design will consist of two independent historical cohorts. Concerning fistula failure to maturation the last three years of performed AVF at the Vascular Department in Viborg, Kolding and Odense are identified in "Karbasen" and reviewed to identify clinical characteristics that are predictive of fistula failure to maturation. Known and suspected risk factors for failure to maturation and death are recorded in a web based REDCAP database.

Concerning aortoiliac calcifications medical records concerning the last three years of pre-transplantation assessment at OUH are reviewed - approximately 200. Independent and dependent variables are entered in a web based REDCAP database.

Data and biological material

From "Karbasen" the AVF will be identified. From the medical records the clinical characteristics will be reviewed (age, gender, race, smoking, diabetes, hypertension, stroke, IHD, PAD, medicine, cause of ureamia, date and type of fistula operation, patency, death.

The CT-scans done prior to renal transplantation are reviewed and the calcification scores are estimated. 

Collaborating researchers and departments

Department of Cardiothoracic and Vascular Surgery T, Odense University Hospital

• Professor Jes Sanddal Lindholt
• Consultant Francois Baudier
• Stud.Med. Jan Rytter
• Stud.Med. Eva Lindhardt Hansen
• Stud.Med. Lily Sarkisian
• Stud.Med. Joachim S.S. Kristensen
• PhD-student Sara Riber

Department of Vascular Surgery, Kolding Hospital

• Consultant Dmitriy Shilenok

Department of Vascular Surgery, Viborg Hospital

• Associate professor Annette Høgh

Institute of Molecular Medicine, University of Southern Denmark

• Associate professor Jane Stubbe

Department of Cardiology B, Odense University Hospital

• Associate professor Axel Diederichsen