Vascular Calcifications in Kidney Transplant Recipient
Condition: Arterial Calcification; Kidney Failure; Kidney Transplant; Complications
MeSH terms: Renal Insufficiency; Arteriosclerosis; Calcinosis
Study type: Observational

Summary: 
      Kidney transplant candidates undergo extensive diagnostic evaluation aimed at assessing their
      cardiovascular (CV) risk, which remains the leading cause of disability and death in this
      patient population. This includes among others an assessment of the iliac arterial
      calcification. Chronic kidney disease (CKD) patients have an increased incidence of arterial
      calcifications due to many factors, such as increased age, hyperparathyroidism, diabetes
      mellitus and hypercholesterolemia. Furthermore, the severity of pelvic arterial
      calcifications may impact the surgical planning of kidney transplantation (KT), choice of
      anastomosis site, complexity of the surgery, and patient and graft survival. Vascular
      calcifications are recognized as a good biomarker of overall cardiovascular burden. Although
      computerized tomography (CT) is the imaging modality of choice for calcification evaluation,
      compared to pelvic X-ray and Doppler ultrasound, it is not officially included in the
      guidelines of different international associations, which offer general recommendations for
      the assessment of iliac vessels. Nevertheless, centers are increasingly using CT in their
      pretransplant workup, either routinely or only in patients with increased CV risk. Also,
      impaired bone metabolism and its consequences have an important role in the development of
      vascular calcification.

      The investigators will determine the relationship between calcification burden of iliac
      arteries which will be assessed on CT and the serum level of bone remodeling biomarkers,
      including parathyroid hormone, (PTH), calcium, phosphates, OPG/RANK/RANKL (engl.
      osteoprotegerin/receptor activator of nuclear factor (NF)-κΒ/RANK ligand) and Gla-Rich
      protein (GLP). According to investigator knowledge, this will be the first prospective study
      that will correlate the degree of iliac arteries calcification based on CT analyses with the
      serum level of various bone remodeling markers, and their impact on clinical outcome in
      kidney transplant recipients.

      The investigators expect this research to improve insights into incidence and distribution of
      iliac artery calcifications in patients following kidney transplantation, their correlation
      with clinical data and bone remodeling markers and confirm the appropriateness of using
      computerized tomography in a routine pretransplantation work-up.
    

Detailed description: 
      The hypothesis of this study is that incidence and severity of arterial calcification raise
      with age of the patient and time spent on hemodialysis. Additionally, poorer graft and
      patient survival and overall risk for future cardiovascular events correlate with the
      severity of arterial calcifications following successful kidney transplantation.

      Study will include 50 patients who will undergo kidney transplantation. Non-contrast CT scan
      of abdomen and pelvis will be performed, and blood level of bone remodeling markers will be
      determined in all patients.

      Two radiologists will independently assess the severity of iliac artery calcifications, by
      using quantitative scoring system developed by Davis et al. and newly developed pelvic
      calcification score.

      Pelvic calcification score (PCS) will be determined by assessing common iliac artery (CIA)
      and external iliac artery (EIA) calcifications bilaterally, based on their morphology (no
      calcification, thin linear calcification, 1mm in thickness and bulky calcification>2mm in
      thickness and convex luminal margins, scores 0-3), circumference and length (no
      calcification, 1-25%, 26-50%, 51-75%, > 76%, scores 0-4, respectively). PCS could vary from
      0-44.

      Serum level of bone remodeling biomarkers will be determined on hospital admission.

      Demographic and clinical data (body mass index - BMI, principal disease and additional
      conditions, type and duration of renal replacement therapy, KT side-and arterial segment
      used, hospitalization time, and graft and overall survival) will be recorded.

      Patients will be followed at least one year after KT, the function of kidney transplant will
      be assessed by measurement of serum creatine and renal scintigraphy
    

Intervention name(s): computerized tomography scanning
Intervention type(s): Other
Intervention description(s): In all patients the investigators will perform CT for determination of iliac arteries calcifications
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients who will undergo kidney transplantation in Clinical Hospital Centre Rijeka,
        following non-contrast CT evaluation will be included in the study.
      
Biospecimen description: 
      whole blood
    
Keywords: kidney transplantation; end stage renal disease; arterial calcifications