What constitutes a significant orthostatic change in blood pressure?

From the Guidelines

A significant orthostatic change in blood pressure is defined as a drop of at least 20 mmHg in systolic blood pressure or a drop of at least 10 mmHg in diastolic blood pressure within three minutes of standing from a sitting or lying position, as stated in the 2024 ESC guidelines for the management of elevated blood pressure and hypertension 1. This definition is crucial for identifying orthostatic hypotension, a condition that can lead to significant morbidity, mortality, and decreased quality of life if left untreated. When assessing for orthostatic changes, blood pressure should be measured after the patient has been lying down for at least 5 minutes, and then again after standing for 1 minute and 3 minutes, as recommended by the guidelines 1. The pathophysiology of orthostatic hypotension involves the pooling of blood in the lower extremities upon standing, reducing venous return to the heart and decreasing cardiac output, which can be exacerbated by factors such as dehydration, certain medications, and autonomic nervous system disorders 1. It is essential to monitor heart rate in addition to blood pressure, as an increase of 30 beats per minute or more can indicate a compensatory mechanism, and to be aware of the potential causes of orthostatic hypotension, including certain medications, autonomic nervous system disorders, and aging 1. By prioritizing the most recent and highest-quality study, we can ensure that our definition and assessment of orthostatic hypotension are evidence-based and aligned with current clinical guidelines, ultimately improving patient outcomes and quality of life. Key points to consider when evaluating orthostatic changes include:

• Measuring blood pressure after at least 5 minutes of rest and then after standing for 1 and 3 minutes
• Monitoring heart rate for compensatory increases
• Being aware of potential causes, such as dehydration, medications, and autonomic disorders
• Recognizing the importance of orthostatic hypotension in patient morbidity, mortality, and quality of life.

From the FDA Drug Label

In a 3-week study in 170 patients, most previously untreated with midodrine, the midodrine-treated patients (10 mg t.i.d., with the last dose not later than 6 P.M.) had significantly higher (by about 20 mmHg) 1-minute standing systolic pressure 1 hour after dosing In a 2-day study, after open-label midodrine, known midodrine responders received midodrine 10 mg or placebo at 0,3 and 6 hours. One-minute standing systolic blood pressures were increased 1 hour after each dose by about 15 mmHg and 3 hours after each dose by about 12 mmHg; In a 1-day, dose-response trial, single doses of 0,2. 5,10 and 20 mg of midodrine were given to 25 patients. The 10 and 20 mg doses produced increases in standing 1-minute systolic pressure of about 30 mmHg at 1 hour;

A significant orthostatic change in blood pressure is at least 15 mmHg accompanied by symptoms such as dizziness/lightheadedness, as patients with pre-existing sustained supine hypertension above 180/110 mmHg were excluded from the studies 2.

• Increases in standing systolic pressure of about 15 mmHg to 30 mmHg were observed in the studies.
• These changes were considered significant in the context of treating orthostatic hypotension.

From the Research

Definition of Significant Orthostatic Change in Blood Pressure

A significant orthostatic change in blood pressure is defined as:

• A fall of ≥20 mmHg in systolic blood pressure within 3 minutes of standing 3, 4, 5, 6
• A fall of ≥10 mmHg in diastolic blood pressure within 3 minutes of standing 3, 4, 5, 6

Key Points

• Orthostatic hypotension (OH) is a common comorbidity among patients with heart failure (HF) 3
• OH is associated with a significant increase in morbidity and mortality, particularly in elderly patients 6
• The first favoring factor for OH is often medications, while other etiologies include neurogenic and non-neurogenic orthostatic hypotension 6
• Treatment of OH requires education of the patient regarding triggering situations and physiological countermanoeuvers, with pharmacological treatment sometimes necessary 6

Diagnostic Criteria

• The diagnosis of OH can be made using a tilt-table test with continuous monitoring of blood pressure and cardiac parameters 4
• The instrumental diagnosis of OH can be easily accomplished with minimal collaboration from the patient 4
• A model to predict the systolic blood pressure drop due to orthostatic hypotension can be developed using heart rate variability measurements extracted from ECGs recorded before standing 7