Left ventricular hypertrophy and nocturnal hypoxemia in hemodialysis patients

Objective Nocturnal hypoxemia has recently been proposed as a cardiovascula r risk factor in patients with chronic renal failure. In this study we have tested the hypothesis that this disturbance is associated with left ventri cular hypertrophy (LVH) in dialysis patients. Methods During a mid-week non-dialysis day, 38 hemodialysis patients underw ent continuous monitoring of arterial O-2 saturation (SaO(2)) during night- time as well as 24 h ambulatory blood pressure monitoring and echocardiogra phy. Results Eighteen patients had one or more episodes of O-2 desaturation duri ng night-time (average: 21 episodes; range 1 to 120) while the other 20 had no episode. Neither day-time arterial pressure nor heart rate were signifi cantly associated with nocturnal hypoxemia, However there was a significant correlation between the night/day systolic ratio and the severity of hypox emia during night-time (r = 0,36, P = 0.03). On multivariate analysis, noct urnal hypoxemia proved to be the stronger independent predictor of relative wail thickness, mean wall thickness and left ventricular mass index, sugge sting that nocturnal O-2 desaturation is linked to concentric hypertrophy a nd to concentric geometry of the left ventricle, Accordingly, the proportio n of patients with such geometric alteration was higher (chi (2) = 4,1, P = 0.04) in patients with a pulse oximetry severity score > 50(th) percentile [15 of 19 (79%)] than in those below this threshold [nine of 19 (47%)]. Conclusions Nocturnal hypoxemia is an important correlate of LVH in hemodia lysis patients. Such an association is largely independent of arterial pres sure, These data further underscore the importance of disturbed respiratory control as a cardiovascular risk factor in dialysis patients. (C) 2001 Lip pincott Williams & Wilkins.