SP_021 Association Between the Vascular Calcification and High Turnover Radiographic Bone Changes in Chronic Kidney Disease Patients Virayavanich W, MD Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Mahidol University, Rama VI Road, Ratchathewi, Bangkok 10400, Thailand E-mail: kaooat7@hotmail.com Category of the paper: Scientific paper
SP_021 Association Between the Vascular Calcification and High Turnover Radiographic Bone Changes in Chronic Kidney Disease Patients Corresponding author: Virayavanich W Co-authurs: Jaovisidha S, Disthabanchong S, Jenjitranant P Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Introduction Chronic kidney disease (CKD) is a worldwide health problem, which affects 5-10% of the world population In CKD patients, vascular calcification is a major cause of cardiovascular disease and associated with increased morbidity and mortality, especially in the dialysis patients (1-6)
Introduction Renal osteodystrophy (ROD) is a disorder of bone turnover or remodeling in the setting of CKD (4, 7, 8) There are 3 major patterns of bone response High-bone turnover - most common form Low-bone turnover Mixed osteodystrophy
Introduction The Kidney Disease Improving Global Outcomes (KDIGO) foundation Suggested relationship between mineral and bone disorder in CKD patients and defined a term CKD-MBD (Chronic kidney disease-mineral and bone disorder) = A systemic disorder of mineral and bone metabolism due to CKD
Introduction Previous studies in CKD patients: Some studies reported an inverse relationship between bone demineralization and vascular calcification (7, 9, 10) Other studies suggested a positive correlation between bone turn over and vascular calcification (1, 4)
Objectives To evaluate the association between vascular calcification and high turnover bone changes observed in pelvic and lumbosacral (LS) lateral spine radiographs in CKD patients
Methods Study population: Out-patient nephrology clinic of Ramathibodi Hospital during January 2009 - March 2012 Inclusion criteria: 1. Chronic hemodialysis patients who were eligible for kidney transplant (KT) waiting list 2. Age between 18-75 years 3. Available Pelvis AP and LS spine lateral radiographs
Methods Exclusion criteria: 1. Patients who had acute illnesses or acute kidney injury 2. A change in serum creatinine >15% within the past 3 months
Methods Demographic assessment: Patient s age, gender, underlying disease, clinical history Enrolled CKD patients Laboratory data: PTH level and serum calcium Radiographic assessment: Pelvis AP and lateral LS spine Bone change related to CKD Vascular calcification
Methods Radiographic assessment of bone changes related to CKD Subchondral bone resorption Sacroiliiac joints Pubic symphysis Subligamentous bone resorption Anteorsuperior iliac spine (ASIS) Anteroinferior iliac spine (AIIS) Ischial tuberosities Greater trochanter Lessor trochanter
Methods Radiographic assessment of bone changes related to CKD Subchondral bone resportion Sacroiliiac joint Pubic symphysis Irregular surface, adjacent reactive sclerosis or pseudo-widening
Methods Radiographic assessment of bone changes related to CKD Subligamentous bone resportion ASIS: Sartorius AIIS: Rectus femoris Greater trochanter: Gluteus medius & minimus Lesser trochanter: Iliopsoas tendon Ischial tuberosity: Hamstring tendons
Methods Radiographic assessment of vascular calcification Abdominal aortic calcification - using lateral lumbar spine radiograph Scored according to Kauppila et al method (Total score 0-24) (11-13) Pelvic vascular calcification (iliac and femoral arteries)- using pelvic radiograph Scored according to Adragao et al method (Total score 0-4) (14, 15) Total VC score = aortic calcification score (maximum score of 24) + (pelvic calcification score x 6) (maximum score of 24) Scored according to Vipattawat et al method (maximum score = 48) (16)
Radiographic assessment of aortic calcification Grading 0: no calcific deposits in front of the vertebra Methods L1 1: small scattered calcific deposits filling less than 1/3 of the longitudinal wall of the aorta L2 2: 1/3-2/3 of the wall calcified L4 L3 Level 3: 2/3 or more of the wall calcified Affected segment Score of the individual segments Posterior wall range 0-3 Anterior wall range 0-3 Composition score (AAC) Anterior-Posterior Severity range 0-6 L1 1 1 3 4 L2 1 2 2 4 L3 1 3 3 6 L4 1 0 3 3 Grading of calcification was assessed at the anterior and the posterior walls of the abdominal aorta adjacent to vertebrae L1-L4 Total 4 9 6 17 Maximum 4 12 12 24 Kauppila LI et.al. Nephrol Dial Transplant (2008) 23: 4009 15 ; Atherosclerosis. 1997 Jul 25;132(2):245-50
Radiographic assessment of pelvic calcification (Iliac and femoral arteries) Methods Divided into four sections by two imaginary lines: a horizontal line over the upper limit of both femoral heads and a median vertical line over the vertebral column Calcification score is the sum of the presence (1) or absence (0) of parallel linear calcifications in each section. In the example, pelvis score = 1+1+1+1 = 4 Adragao T. Nephrol Dial Transplant (2004) 19(6): 1480 8
Materials and methods Vascular calcification Total VC score (maximum score of 48) Aortic calcification score (maximum score of 24) Pelvic calcification score x 6 (maximum score of 24) Vipattawat K et al. Vascular calcification in long-term kidney transplantation. Nephrology. 2014 Apr;19(4):251-6
Results Table 1: Patient characteristics
Table 2: Radiographic bone changes in chronic hemodialysis patients Results
Table 3: Prevalence and severity of vascular calcification Results
Table 4: Association between vascular calcificationa and radiographic bone resorption in hemodialysis pateints Results
Results No significant correlation between radiographic bone change and age (p = 0.762) The vascular calcification Significant correlation with age (r = 0.496, p < 0.001) Not correlate with serum PTH level (r = 0.280, p = 0.761)
Discussion Our study: The association between CKD related bone changes and vascular calcification, using AP pelvic and lateral LS spine radiographs Routinely used for screening VC Modovan et al and Coen et al: The positive correlation between high bone turn over and VC in CKD patients Our study: The significant association between vascular calcification and subligamentous/subtendinous resorption No association between vascular calcification and subchondral bone resorption
Discussion The exact mechanisms of the relationship between bone turnover and vascular calcification is not clearly defined. Small number of positive radiographic bone changes Subchondral resorption (19.8%) & Subligamentous/subtendinous resorption (14%) Not represent all the CKD patients A positive correlation between age and vascular calcification The vascular calcification tends to increase in older patients
Discussion Limitation: Cross-sectional study Not determine the consequences of the developing vascular calcification and bone changes Need further longitudinal study Plain radiograph is less accurate and less sensitive than CT in detection of vascular calcification The vascular calcification scoring technique is not routinely used in our institution
Conclusions Chronic hemodialysis patients demonstrated significant association between vascular calcification and subligamentous/subtendinous resorption that encourages the pathologic link between bone changes related to high bone turn over and the vascular calcification in CKD patients
Conflict of interest The authors declare no conflict of interest
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