Elevated uric acid levels predict allograft vasculopathy in cardiac transplant recipients.
BACKGROUND
Cardiac allograft vasculopathy (CAV) poses the greatest threat to the long-term survival of cardiac transplant recipients, and these individuals often exhibit elevated levels of uric acid (UA), a stimulator of T cells. We hypothesized that hyperuricemia is associated with CAV in cardiac transplant recipients.


METHODS
UA levels were measured in cardiac transplant recipients between January 2003 and January 2005. Surveillance cardiac catheterizations performed 3 months to 1 year after UA measurement were reviewed. The relationship between UA and CAV was adjusted for possible confounders with propensity scores and confirmed with goodness-of-fit tests.


RESULTS
The 105 patients included in this study were a median 63.3 months post-transplant and their left heart catheterizations were performed a median 5.6 months after UA measurement. Focal stenosis was evident in 25 angiograms and 31 showed distal pruning of the coronary arteries. Compared with the lowest quartile of UA, the highest quartile had an increased risk of CAV: odds ratio (OR) 6.11 (95% CI 1.47 to 25.5; p = 0.013) for focal stenosis and OR 4.60 (95% CI 1.34 to 15.8; p = 0.015) for distal pruning. After adjustment, this relationship persisted for both focal stenosis (OR 5.53, 95% confidence interval [CI] 1.29 to 23.7; p = 0.021) and distal pruning (OR 4.21, 95% CI 1.15 to 15.4; p = 0.029).


CONCLUSIONS
Elevated UA confers an increased risk of CAV. This association may be causal, with pathophysiologic implications for the role of hyperuricemia in allograft failure and, if substantiated, could have clinical implications for the use of xanthine oxidase inhibitors in cardiac transplant recipients.
Kittleson
Michelle M
MM
Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
Bead
Valeriani
V
Fradley
Michael
M
St John
Marcus E
ME
Champion
Hunter C
HC
Kasper
Edward K
EK
Russell
Stuart D
SD
Wittstein
Ilan S
IS
Hare
Joshua M
JM
D000368:Aged; D015415:Biomarkers / Q000032:analysis; D015331:Cohort Studies; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006084:Graft Rejection / Q000175:diagnosis* / Q000453:epidemiology; D006085:Graft Survival; D016027:Heart Transplantation / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013997:Time Factors; D014184:Transplantation, Homologous / Q000009:adverse effects; D014527:Uric Acid / Q000097:blood*
D015415:Biomarkers; D014527:Uric Acid