Obstructive sleep apnoea syndrome (O-SAS) induces excessive activity of the sympathetic nervous system, resulting in secondary hypertension. Although continuous positive airway pressure (CPAP) is the first-line therapy for O-SAS, poor adherence to CPAP induces uncontrollable resistant hypertension. We present a case of O-SAS-related hypertension successfully treated with sacubitril/valsartan alone. Polysomnography before treatment showed a markedly increased apnoea-hypopnoea index (44.8/hour). While receiving treatment with CPAP and azilsartan, his in-office blood pressure remained within the acceptable range (120–130/80–85 mmHg). However, his blood pressure increased again after quitting CPAP. Subsequently, we switched to sacubitril/valsartan alone and succeeded in improving his blood pressure from 145/95 to 120/80 mmHg. Furthermore, sacubitril/valsartan improved sleep quality in terms of blood pressure (from non-dipper type to dipper type) and apnoea-hypopnoea index (38.3/hour). This case indicates that sacubitril/valsartan has great potential for antihypertensive effects in patients with severe O-SAS, even without CPAP.
