Impact of Obstructive Sleep Apnea and Snoring on Left Ventricular Mass and Diastolic Function in Hypertensive Nigerians

BACKGROUND: Systemic hypertension (HTN) and obstructive sleep apnea (OSA) are individually associated with left ventricular structural and functional adaptations. However, little is known about the impact of OSA on the left ventricle in Africans with HTN. AIM: The aim of this study is to determine the association between OSA and left ventricular mass (LVM) and diastolic dysfunction in Nigerian hypertensive subjects. SUBJECTS AND METHODS: A total of 104 hypertensive subjects were enrolled for this study. Risk for OSA was assessed with the Berlin score. Clinical history and examination were performed. Echocardiography was performed and diastolic dysfunction was diagnosed using the pulse wave Doppler. Statistical analysis was performed using the statistical package for social sciences 17.0. (Chicago Ill, USA). Comparism between groups was done using t-test and Chi-square and P < 0.050 was taken as statistically significant. RESULTS: LVM, posterior wall and interventricular septum were significantly higher among hypertensive patients with high risk for OSA than those with low risk (263.610 g [11.202] g vs. 208.714 g [47.060] g; 12.100 mm [2.712] mm vs. 10.711 mm [2.101] mm; 13.210 [3.114] mm vs. 11.700 mm [2.402] mm respectively). A similar finding was reported between hypertensive snorers and hypertensive non-snorers. Fasting blood glucose was also significantly higher among hypertensive snorers than non-snorers. However, mean transmitral early (E) to late (A) flow E/A ratio was lower among hypertensive with low risk of OSA and snorers than those with a high risk and non-snorers respectively. Left Ventricular hypertrophy was also more common among hypertensive with high risk of OSA than non-snorers and low risk of OSA (39/55, 70.9% vs. 28/49, 57.1% respectively, P < 0.05). CONCLUSION: OSA is associated with significant additional left ventricular changes in hypertensive subjects. Therefore, aggressive effort at managing OSA and snoring among hypertensive subjects may further reduce their cardiovascular risk.