Severity of obstructive sleep apnea is associated with left ventricular abnormality in patients with hypertension in the young

Abstract

Abstract Background Hypertension in the young is defined as the presence of hypertension in individuals with an age of onset before 35 years. A previous study found that obstructive sleep apnea (OSA) may be a contributing factor of hypertension in the young up to 90% if other causes of secondary hypertension were excluded. Left ventricular (LV) abnormality is a marker of future cardiovascular consequences. There is limited data on risk factors of LV abnormality in patients with hypertension in the young with OSA. Objectives We aim to evaluate risk factors of LV abnormality in patients with hypertension in the young. Methods This study was a retrospective study. The eligible patients were adult patients who diagnosed as hypertension at age before 35 years and evaluated for echocardiogram. Those with causes of secondary hypertension or pregnant women were excluded. The study period was between October 2017 and January 2021. OSA was categorized as mild, moderate, and severe by an apnea-hypopnea index of 5-14.9, 15-29.9, and 30 or over times/hour. LV abnormality defined by relative wall thickness (RWT) over 0.42 mm. by a Doppler echocardiography. Other echocardiographic findings were also reported including left ventricular mass (LVM), left ventricular mass index (LVMI), and ejection fraction (EF). Differences of variables among severities of OSA were computed by a one-way ANOVA, while differences of proportions between groups were calculated by Chi square test. Multivariable analyses, linear and logistic regressions were performed to find the association between OSA and LV abnormality. Results There were 52 patients who met the study criteria. Mild OSA group had lower LVM, LVMI, and RWT than moderate OSA and severe OSA group (172.98 vs 232.16 vs 177.78 g; p 0.036 for LVMI; 83.03 vs 107.87 vs 84.99 g/m2; p 0.013 for LVMI; and 0.38 vs 0.45 vs 0.47 mm; p 0.010 for RWT). There was no significant difference in EF among the three groups. Severe OSA was found have an increased association with the presence of LV abnormality compared to patients with mild to moderate OSA (OR 3.28, 95% CI 0.96-12.5), however this was not statistically significant (p-value 0.07) Patients with severe OSA was found to have a correlation with RWT measurements of greater than 0.42 (correlation co-efficient 0.2, 95% CI 0.01-0.39, p-value 0.04). Conclusion Hypertensive patients under the age of 35 with severe OSA have a higher proportion of LV abnormality compared to mild and moderate OSA. Severe OSA was found to be correlated to RWT measurements of greater than 0.42. This finding might be one of prognostic indicators of the future adverse cardiovascular events and be required proper management. However, this relationship should be needed further study.