Carotid intima-media thickness in kidney transplant recipients

Abstract

Background/Purpose

Cardiovascular disease is the leading cause of mortality among kidney transplant recipients. Carotid intima-media thickness (CIMT) of the common carotid artery is a surrogate marker for early atherosclerosis. We wanted to compare the prevalence of increased CIMT among kidney transplant recipients with matched controls and its association with clinical and laboratory parameters.

Methods

A comparative cross-sectional study involving kidney transplant recipients and controls matched for age, sex, chronic kidney disease staging, and cardiovascular risks was used. CIMT measurements were done using carotid ultrasound and considered increased if >75^th percentile matched for age- and sex-matched normal controls. Standard laboratory investigations, high sensitivity C-reactive protein, and asymmetric diamethylarginine were analyzed.

Results

Thirty-six kidney transplant recipients (25 men, 11 women) with a median age of 41 years [interquartile range (IQR), 38–52 years] and 36 matched controls with a median age of 44 years (IQR, 37–53 years) were enrolled. There were no demographic differences between the two groups. Kidney transplant recipients had a significantly increased CIMT, 0.8 mm (IQR, 0.6–0.9) compared to matched-controls 0.55 mm (IQR, 0.5–0.7, p = 0.001). Two thirds of kidney transplant recipients had increased CIMT, which was associated with a higher low density lipoprotein (LDL) (p = 0.022) and higher hemoglobin (p = 0.006). Smoking status (p = 0.058) and male sex (p = 0.073) had a trend towards significance to increased CIMT. Multiple linear stepwise regression demonstrated both age and hemoglobin were independent predictors of CIMT (p < 0.001). We found no relationship between high sensitivity C-reactive protein and asymmetric diamethylarginine with CIMT.

Conclusion

CIMT among our kidney transplant recipients was significantly higher compared to controls thereby increasing their cardiovascular risk.

背景

心血管疾病是腎臟移植接受者的主要死因,總頸動脈的內膜中膜厚度 (CIMT) 則是早期動脈粥樣硬化的替代性指標。在本研究中,我們比較了 CIMT 增厚於腎臟移植接受者與匹配對照組之間的盛行率,並調查了 CIMT 與臨床及實驗室參數之間的關聯。

方法

這是一項橫斷式比較性研究,涉及的對象包括腎臟移植接受者、及與其匹配 (年齡、性別、慢性腎病分期及心血管風險) 的對照者。CIMT 以頸動脈超音波測量,增厚的定義為對應年齡性別匹配正常對照組之 > 75^th 百分位數。其他測量項目除了標準實驗室參數外,亦包括高敏感度 C-reactive protein (hs-CRP) 及 asymmetric diamethylarginine (ADMA)。

結果

分析對象包括 36 位年齡中位數 41 歲 (38,52) 之腎臟移植接受者 (25 男、11 女) 及 36 位年齡中位數 44 歲 (37,53) 之匹配對照者,兩組間的人口學特徵並無不同。腎臟移植接受者之 CIMT 為0.8 mm (0.6,0.9 mm),明顯高於匹配對照者之 0.55 mm (0.5,0.7 mm) (p = 0.001)。腎臟移植接受者之間,3 分之 2 呈現 CIMT 增厚的情形,較厚的 CIMT 與較高的低密度脂蛋白 (p = 0.022) 及較高的血色素 (p = 0.006) 有關。吸煙狀況 (p = 0.058) 及男性性別 (p = 0.073) 亦有傾向與 CIMT 增厚有關。多變項線性逐步迴歸分析顯示,年齡及血色素均是CIMT的獨立預測因子 (p < 0.001)。對於 CIMT 與 hs-CRP 或 ADMA 數值之間,我們並未發現明顯的關係。

結論

在本研究的腎臟移植接受者中,CIMT 明顯高於對照組,因此具較高的心血管風險。