What is orthostatic hypertension?

Orthostatic Hypertension: Definition and Clinical Significance

Orthostatic hypertension is defined as an exaggerated increase in blood pressure (≥20 mmHg in systolic blood pressure) when changing from a supine to standing position, with the term "orthostatic hypertension" specifically reserved for when this pressor response leads to an upright systolic blood pressure ≥140 mmHg. 1

Definition and Diagnostic Criteria

Orthostatic hypertension differs significantly from the more commonly recognized orthostatic hypotension:

• Orthostatic hypertension: Sustained increase in blood pressure upon standing

  • Systolic blood pressure increase ≥20 mmHg when moving from supine to standing 1
  • Standing systolic blood pressure ≥140 mmHg 1

• Orthostatic hypotension: Sustained decrease in blood pressure upon standing

  • Decrease in systolic BP ≥20 mmHg and/or diastolic BP ≥10 mmHg within 3 minutes of standing 2
  • In patients with supine hypertension, a systolic BP drop ≥30 mmHg is considered significant 2

Pathophysiology

The primary pathophysiological mechanism in orthostatic hypertension appears to be:

• Dysfunction of the autonomic nervous system 3
• Excessive neurohumoral activation while standing 4
• Similar to orthostatic hypotension, but with an opposite hemodynamic response

Clinical Significance and Risk

Orthostatic hypertension has important clinical implications:

• Predicts risk for progression to arterial hypertension in younger individuals 4
• Associated with increased cardiovascular morbidity and mortality in older persons 4
• May be associated with target organ damage, though evidence is mixed 3
• Recent research suggests standing hypertension (≥140 mmHg) may be more strongly associated with cardiovascular disease outcomes than the orthostatic increase itself 5

Screening and Detection

To properly detect orthostatic blood pressure changes:

• Measure blood pressure after 5 minutes of rest in the supine or sitting position 2
• Then measure again at 1 minute and/or 3 minutes after standing 2
• For orthostatic hypertension, look for a rise in systolic BP ≥20 mmHg 1
• For orthostatic hypotension, look for a drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg 2

Clinical Management Considerations

While specific treatment guidelines for orthostatic hypertension are lacking due to limited evidence:

• Screening for abnormal orthostatic blood pressure responses is reasonable in hypertensive patients 4
• Both orthostatic hypotension and hypertension herald increased cardiovascular risk 4
• Management decisions should consider the overall blood pressure profile, including supine and standing measurements
• Detailed characterization of blood pressure variability using both in-office and out-of-office monitoring can help tailor treatment 6

Pitfalls to Avoid

• Inconsistent measurement technique: Follow standardized protocols for orthostatic blood pressure assessment
• Inadequate monitoring duration: Monitor for at least 3 minutes to detect classical orthostatic changes 7
• Overlooking absolute BP values: Both the magnitude of change and the absolute BP values are important 7
• Misdiagnosis in elderly: Be aware of pseudohypertension in elderly patients, which can lead to overtreatment and orthostatic hypotension 7

Orthostatic hypertension remains an underrecognized condition that deserves more clinical attention given its association with cardiovascular risk. Further research is needed to establish optimal management strategies for this condition.