H- 14 : Transplant monitoring
H- 15 : Hypertension and CV complications
Clinical Significance of Preexisting Microcalcification in the Iliac Artery in
Renal Transplant Recipients
Hwang, Hyeon Seok1; Lim, Sun Woo2; Sun, In O.1; Yang, Keun Suk1; Yoon, Hye Eun1; Chung, Byung
Ha1; Choi, Bum Soon1; Choi, Yeong Jin3; Kim, Ji Il4; Sung Moon, In4; Kim, Suk Young1; Yang, Chul
Woo1,2
Author Information
1
Division of Nephrology, Department of Internal Medicine, The Catholic University of Korea, Seoul,
Korea.
2
Convergent Research Consortium for Immunologic Disease, Seoul St. Mary’s Hospital, Seoul, Korea.
3
Department of Pathology, The Catholic University of Korea, Seoul, Korea.
4
Department of Surgery, The Catholic University of Korea, Seoul, Korea.
Correspondence: Chul Woo, Yang, M.D., Ph.D., Division of Nephrology, Department of Internal
Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea 641 Banpo-ro, Seocho-Ku, Seoul
137-040, Korea. (yangch@catholic.ac.kr).
Journal : Transplantation
Year : 2015 / Month : April
Volume : 99
Pages : 811–817
doi: 10.1097/TP.0000000000000409
ABSTRACT
Background
The clinical significance of preexisting microcalcification in the iliac artery is undetermined in renal
transplant recipients.
Methods
We obtained iliac artery segments from 90 transplant recipients at the time of renal transplantation and
performed von Kossa staining for microcalcification. The clinical significance of intimal
microcalcification was evaluated with allograft survival rate, rate of graft function decline, and
composite of any cardiovascular event or patient death. Expression of fetuin-A and C-reactive protein,
key regulators of calcification, was also investigated in the iliac artery.
Results
Intimal microcalcification was positive in 48 (53.3%) patients, and its intensity was correlated positively
with intimal C-reactive protein intensity (P = 0.019). Allograft survival in patients positive for intimal
microcalcification was lower than patients who were negative (P = 0.017). The patients with positivity
for both intimal microcalcification and fetuin-A showed lower allograft survival rate than patients with
intimal microcalcification positivity alone (P = 0.012). The rate of renal graft function decline was
significantly steeper in patients positive for intimal microcalcification than in patients who were negative
(P = 0.036). In multivariate analysis, positivity for both intimal microcalcification and fetuin-A was an
independent predictor for renal graft function decline (β = −10.21; P = 0.011). The intimal
microcalcification was not associated with composite-event free survival.
Conclusion
Preexisting intimal microcalcification in the iliac artery predicts a lower allograft survival rate and rapid
decline of allograft function. Positivity of fetuin-A with intimal microcalcification further reduces allograft
survival rate and an independent predictor for renal graft function decline.
COMMENTS
Preexisting vascular calcification is an important risk factor in renal transplant recipients.
Vascular calcification is divided into the two distinct entities of intimal and medial calcification. Of these,
intimal calcification represents atherosclerosis and is associated with the development of plaques and
occlusive lesions. Fetuin-A involves the calcific process as an inhibitor of vascular calcification and has
anti-inflammatory properties. Fetuin-A levels have an inverse relationship with C-reactive protein
(CRP), which is a representative marker of inflammation.
90 incident renal transplant recipients who provided an iliac artery specimen were enrolled in the study.
The iliac artery segments were obtained during renal transplant surgery. Relevant demographic and
clinical information was collected retrospectively at the time of renal transplantation. Radiologic
calcification was determined from plain X-ray images of the chest and abdomen performed at the time
of renal transplantation. The assessment of arterial calcifications in the aortic arch, chest and
abdominal aorta and iliofemoral axis was estimated.
This study clearly demonstrates that the intimal microcalcification in the iliac artery at the time of renal
transplantation predicts a lower allograft survival rate and steeper decline of renal allograft function.
The intimal fetuin-A positivity revealed further reduced allograft survival rate in patients with positive
intimal microcalcification, and positivity for both intimal microcalcification and intimal fetuin-A was
independently associated with rapid graft function decline. These findings suggest that intimal
microcalcification in the iliac artery is an important factor for determining graft prognosis in renal
transplant recipients.
More than half of patients were positive for intimal microcalcification, and it was higher than those of
calcification observed on plain X-ray images (53.3% vs. 24.4%). Interestingly, the intimal
microcalcification score did not differ between patients with and without calcification observed on any
X-ray images (1.3 vs. 1.2; P = 0.260), and the positivity for pelvic X-ray calcification also showed
similar results. Furthermore, the traditional risk factors for radiographic calcification (age, prevalence of
diabetes, and time on dialysis) were not associated with intimal microcalcification.
To conclude, the intimal microcalcification in the iliac artery at the time of renal transplantation predicts
a lower allograft survival rate and steeper decline of renal allograft function. Positivity of fetuin-A with
intimal microcalcification further reduces allograft survival rate and an independent predictor for rapid
decline of graft function.
Pr. Jacques CHANARD
Professor of Nephrology
.