Influence of sleep related hypoxaemia on left ventricular hypertrophy in mild to moderate hypertensives

Abstract

To evaluate the possible relationship between the nocturnal hypoxaemia and left ventricular hypertrophy (LVH) in patients (pts) with arterial hypertension (AH), we investigated untreated 50 hospitalized pts (mean age 52±2y, 40m and 10f) with mild to moderate AH. Noninvasive 24-h blood pressure (BP) recordings (SpaceLabs 90207 or TM-2425, AD) were performed with intervals of 15 min during the day- and 30 min during the nighttime. Left ventricular mass was assessed by echocardiography (Devereux) and normalized by body surface area (LVMI). The pts underwent 7–8 hours of continuos monitoring (NONIN-8500 M) of arterial oxygen saturation during sleep. The results were analyzed with original program ≪ARM-SaO2≫. The nocturnal hypoxaemia was assessed using the number of 4% desaturation (DN) from the baseline stabile value, during the monitoring. According by tertil values of DN, pts were divided into three groups: Gr.I (DN<10), Gr.II (10≤DN<35) and Gr.III (DN≤35). Differences of estimated parameters between groups were tested by Kruskal-Wallis ANOVA, the prevalence of LVH (LVMI>125 g/m2 for males and LVMI>110 g/m2 for females) - by Fisher's exact test. The relationship between LVMI, LVH and other variables were assessed by Spearman rank order correlation analysis. There were no significant differences between groups by body mass index (29±6 vs 28±3 vs 31±6 kg/m2) and duration of AH (12±9 vs 10±5 vs 11±7 y). The pts in the Gr.I and Gr.II were significantly younger in comparison with Gr.III (49±10. 49±9 vs 57±11 y; p<0.05). There were no significant differences between groups by daytime (D) and nighttime (N) values of systolic and diastolic BP-s (SBP and DBP). LVMI and the presence of LVH were significantly higher in the Gr.III. Spearman rank order correlation analysis showed, that DN significantly correlated with LVMI (0.41, p<0.003) and the presence of LVH (0.32, p<0.05). There is not significant correlation between the age of patients and LVMI (0.2, p=0.1). Our results suggests that the number of nocturnal desaturation is a risk factor for left ventricular hypertrophy in patients with mild to moderate arterial hypertension. (See Table) −P<0.05 Gr.II and Gr.III. −p<0.05 Gr.I and Gr.III −p<0.05 all Gr. −P<0.05 Gr.II and Gr.III. −p<0.05 Gr.I and Gr.III −p<0.05 all Gr.