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Abstract
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It has been 140 years since the sphygmomanometer was invented by Samuel Siegfried Karl Ritter von Basch, making it possible to measure blood pressure. Today, manual sphygmomanometers have now largely been replaced by automated oscillometric versions, for not just the clinic but also the home. In addition, ambulatory versions that are able to obtain automated measurements at regular intervals, usually 15 to 30 minutes during the day and 30 to 60 minutes at night, allow for more frequent recording, providing us with a 24‐hour blood pressure profile that now often guides therapy choice.
The limited advances in clinical availability of equipment that produces more than just snapshot measurements have more or less led to the current confusion on the implication of orthostatic hypotension (OH), let alone the actual diagnostic criteria for OH. All but a few published studies to date have used oscillometric measurement methods to obtain snapshot measurements in the supine position, followed by single measurements obtained within 3 minutes of the patient standing up.2 Such methods of measurements will end up missing significant blood pressure decreases, which occur at times outside the point the single measurement is taken. With the advent of noninvasive beat‐to‐beat blood pressure measurement technology, which has yet to become widely available in clinical practice, the long‐standing definition of a decrease in systolic blood pressure of 20 mm Hg or diastolic blood pressure of 10 mm Hg with standing is now being challenged, with a revised definition suggesting “sustained” reductions are needed before OH can be diagnosed (classic OH), because using beat‐to‐beat technology, transient decreases exceeding 20 mm Hg systolic and 10 mm Hg diastolic are present in a large number of individuals with no reported symptoms.3 In addition, the new consensus committee also added in the diagnostic criteria for initial OH, which requires a decrease of at least 40 mm Hg systolic and 20 mm Hg diastolic within 15 seconds of standing.
The clinical relevance of determining the presence of OH would be to identify a potential underlying cause for dizziness, falls, or syncope, which could be attributed to underlying autonomic neuropathy, hypovolemia, or medications. As clinics generally use oscillometric measurements, the presence of a documented decrease that fulfils current criteria for classical OH may not be relevant to the clinical presentation, with clinicians prompted to also rule out other attributable causes unless the magnitude of decrease is too large or the patient reports reproduction of symptoms. However, the risk of OH, falls, and syncope all increase with age, with nonspecific presentations often complicating the diagnostic process. Specifically, the older adult may have a lack of awareness of hypotensive symptoms, hence challenging the diagnostic relevance of symptom reproduction in this age group.4 Furthermore, the presence of hypotensive disorders and the magnitude of postural decrease have been linked to the volume of deep white matter hyperintensities on magnetic resonance imaging, suggesting a possible link between transient decreases in blood pressure and cognitive disorders ...
Language: en |