維持透析患者の運動耐容能に関する研究 ： 腎性貧血の関与とエリスロポエチン治療の影響

Abstract

V̇In this study the effects of renal anemia on exercise tolerance and cardiac function were evaluated in maintenance hemodialysis patients. Twenty-seven patients were classified into two groups according to hemoglobin concentration (Hb) level (Group A1 : patients with Hb 7.0 g/dl or more ; Group A2 : patients with Hb 7.0 g/dl or less). Peak oxygen consumption (⩒o₂ peak) and anaerobic threshold (AT) were measured by cardiopulmonary exercise test, echocardiography was carried out and arterial blood oxygen transport capacity (O₂ transport capacity) was calculated. Further, the fourteen patients of Group A2 were re-examined after correction of anemia by recombinant human erythropoietin (EPO). (1) The exercise tolerance of maintenance hemodialysis patients was significantly reduced, about 50 per cent compared with the control group, and Group A2 showed lower ⩒o₂ peak and AT level than Group A1. (2) There was a significant correlation between Hb and exercise tolerance, and a closer correlation was shown between O₂ transport capacity and exercise tolerance. (3) There were significant elevations in ⩒o₂ peak (17.6±4.9 to 22.5±4.5 ml/min/kg) and AT (9.8±3.6 to 13.4±3.3 ml/min/kg) after improvement of renal anemia by EPO. (4) Because of improvement of anemia by EPO, left atrial dimension, left ventricular end-diastolic dimension and left ventricular mass were decreased. (5) Because of improvement of anemia by EPO, each significant decrease was shown in heart rate, pressure rate product, blood lactate concentration and plasma norepinephrine concentration during steady-state exercise. These findings suggest that patients with anemia who are undergoing maintenance hemodialysis show remarkably decreased exercise tolerance, and correction of anemia by EPO improves cardiac function, exercise tolerance and neurohumoral response to exercise.