Organic and functional evaluation of atherosclerosis in renal transplant recipients

Abstract

We evaluated atherosclerotic lesions in 18 renal transplant recipients in whom the grafts remained functional after transplantation from living donors at the Sakai Hospital, Kinki University School of Medicine. In each patient, the mean intima-media thickness of the bilateral common carotid arteries (mIMT) was measured by ultrasonography. In the pulse wave test, the ankle brachial index (ABI) and the brachial-ankle pulse wave velocity (ba-PWV) were measured. In 12 (66.7%) of the 18 renal transplant recipients examined, the mean value of ba-PWV was higher than the mean plus 1 standard deviation (SD) in the corresponding Japanese age group. A significant correlation was noted between mIMT (an organic indicator of atherosclerosis) and ba-PWV (a functional indicator of atherosclerosis). The age at the time of test, blood pressure and the pre-transplant duration of hemodialysis had a significant positive correlation with both mIMT and ba-PWV. Thus in renal transplant recipients, organic evaluation of atherosclerosis correlated significantly with its functional evaluation. Both evaluations were proven to be reliable. Many of the renal transplant recipients had complications from atherosclerosis, and several factors seemed to be involved in the onset of atherosclerosis in these patients. Among others, the duration of hemodialysis before transplant correlated particularly closely with post-transplant onset of atherosclerosis, and it seems likely that persistent uremia can stimulate the progression of atherosclerosis.

背景:動脈硬化は移植腎生着や患者生存に関わる重要な因子である。そこでわれわれは, 腎移植患者に対する動脈硬化性病変の評価を行い, その意義を検討した。方法:近畿大学医学部堺病院で生体腎移植を施行し生着中である18名の腎移植患者を対象とした。頸動脈エコーでは, 左右の平均総頸動脈内中膜複合体厚(mIMT)を計測した。脈波測定検査は足首上腕血圧比(ABI)および上腕足首脈波伝導速度(ba-PWV)を測定した。結果:測定を行った腎移植患者では18例中12例(66.7%)で年代別基準値の1SDを超える高値を呈していた。動脈硬化の器質的評価であるmIMTと機能的評価であるba-PWVの両者間に有意な相関を認めた。mIMTとba-PWVの両者と有意な正相関を認めたのは, 検査時の年齢, 血圧, 移植前の透析期間であった。結論:腎移植患者における動脈硬化の器質的評価と機能的評価には有意な相関があり, いずれも信頼性のある方法と考えられた。また, 腎移植患者は動脈硬化症を合併する例が多く, その発症にはいくつかの因子が関与すると考えられた。なかでも移植前の透析期間は動脈硬化と強く関連しており, 尿毒症状態の長期化が動脈硬化の進行を誘発すると考えられた。(著者抄録)