小室 薫¹, 横山 典子², 渋谷 美咲², 早乙女 和幸², 広瀬 尚徳¹, 米澤 一也³, 安在 貞祐¹

Kaoru KOMURO¹, Noriko YOKOYAMA², Misaki SHIBUYA², Kazuyuki SOUTOME², Masanori HIROSE¹, Kazuya YONEZAWA³, Teisuke ANZAI¹

¹国立病院機構函館病院循環器科, ²国立病院機構函館病院臨床検査科, ³国立病院機構函館病院臨床研究部

¹Department of Cardiology, National Hospital Organization, Hakodate Hospital, ²Clinical Laboratory, National Hospital Organization, Hakodate Hospital, ³Department of Clinical Research, National Hospital Organization, Hakodate Hospital

キーワード : cardiovascular disease, cardiac events, renal Doppler ultrasonography, resistive index

背景と目的：慢性腎疾患は心血管疾患（CVD）の危険因子である．腎ドプラエコー法による腎末梢血管抵抗値（resistive index: RI）は腎機能障害と関連している．我々はRIと心機能との関係を調べ，CVD患者に起こるイベントを予測するためのRIの有用性を評価した．方法と結果：腎臓のドプラエコー法と心エコー検査を計452名のCVD患者に行った．RIと，血清クレアチニンおよび推算糸球体濾過率（eGFR）との相関は有意ではあったが強くはなかった（それぞれr＝0.37，p ＜ 0.001; r＝-0.42，p ＜ 0.001）．RIは，年齢，左心房容積係数，左室心筋重量係数，経僧帽弁血流の拡張早期成分（E）と拡張早期僧帽弁輪速度（e′）の比（E/e′）とは正の相関を，e′と拡張期血圧とは有意な負の相関を示した．2つのグループ，すなわち心血管イベントで入院した患者112名（A群）と，年齢およびeGFRを一致させた200名から成る対照群（B群）の間において，年齢とeGFRに差がないにも関わらず，RIはB群よりもA群において明らかに高値であった．結論：RIはeGFRだけでは十分に説明できない腎内血行動態の異常を反映する．腎臓RIは心血管疾患患者での予後推定に役立つと考えられる．

Background and purpose: Chronic kidney disease is a risk factor for cardiovascular disease (CVD). Renal resistive index (RI) measured by Doppler ultrasonography is associated with renal impairment. We investigated the relationship between RI and cardiac function, and evaluated the utility of RI for predicting cardiac events in patients with CVD. Methods and results: Renal Doppler ultrasonography and echocardiography were performed in a total of 452 patients with CVD. Correlations of RI with serum creatinine and estimated glomerular filtration rate (eGFR) were significant but not strong (r=0.37, p〈0.001; r=-0.42, p〈0.001, respectively). RI correlated positively with age, left atrial volume index, left ventricular mass index, and early transmitral velocity to mitral annular early diastolic velocity (e′) ratio (E/e′), and showed significant negative correlations with e′ and diastolic blood pressure. Between two subgroups-112 patients hospitalized with cardiovascular events (Group A) and 200 age- and eGFR-matched controls (Group B)-RI was significantly higher in Group A than in Group B, although age and eGFR were similar. Conclusions: RI reflects the impairment of intrarenal hemodynamics that cannot be adequately elucidated by eGFR alone. Assessment of renal RI may be useful in conjunction with prognostic estimates for patients with CVD.