In 2017, MultiCare received an award from the Patient-Centered Outcome Research Institute (PCORI) to develop and explore issues related to high blood pressure and hypertension. We are currently holding monthly stakeholder meetings to explore this topic.
Together, our goal is to build a specialized research program for patients with sleep apnea that are dealing with multiple chronic health conditions.
Hypertension (HTN) affects one in three adults in the United States. Hypertension is considered “resistant” when blood pressure (BP) remains greater than or equal to 140/90 mmHg, despite lifestyle modification and the administration of three antihypertensive agents of different classes, including a diuretic.
Drug-resistant high blood pressure (RHBP) is a common clinical problem, present in 20 to 30 percent of HTN trial patients, but it has an undetermined prevalence rate in the US. RHBP presents aggressive cardiovascular and cerebrovascular risks, often resulting in catastrophic adverse events such as stroke, myocardial infarction (MI), or congestive heart failure (CHF). RHBP also substantially increases the risk of organ damage leading to kidney disease or failure, vision loss and peripheral artery disease.
RHBP can be attributed to several secondary causes. Obstructive sleep apnea (OSA) is the most often undiagnosed and untreated among these secondary causes. Sufficient evidence supports that OSA is not only strongly associated with HTN and RHBP, but also predicts progression into future hypertension in individuals who currently have normal blood pressure. The pathophysiological mechanisms linking OSA and RHBP have been widely studied and discussed, but remain only partially understood.
The mechanism proposed is a pattern of intermittent hypoxia, associated with hyperaldosteronism, increased sympathetic tone, endothelial dysfunction, and inflammation. Evidence also shows that OSA severity is directly and positively correlated with higher blood pressure elevation and lower likelihood of blood-pressure control despite the use of an increasing number of antihypertensive medications. Hypertension occurring in subjects with OSA is more likely to be severe, resistant to treatment and associated with alterations in day-to-night blood pressure changes, including a non-dipping pattern (usually defined as a nocturnal BP fall of less than 10 percent).