Orthostatic Hypotension in Parkinson Disease: How Much You Fall or How Low You Go?

Abstract

Background Orthostatic hypotension (OH) is frequent in patients with Parkinson disease (PD) and can occur with or without symptoms. Pharmacological treatments are effective but often exacerbate supine hypertension. Guidelines exist for the diagnosis but not for the treatment of OH. We examined the relationship between blood pressure and symptoms in a cohort of PD patients with the goal of identifying a hemodynamic target to guide treatment. Methods We measured blood pressure supine and upright (tilt or active standing) and identified the presence or absence of symptomatic OH by using a validated patient-reported outcome questionnaire in 210 patients with PD. We evaluated the usefulness of the 20/10 and 30/15 mmHg diagnostic criteria (systolic/diastolic) to identify symptomatic OH. Results Fifty percent of the PD patient cohort met criteria for the 20/10 fall and 30% for the 30/15 blood pressure fall. Among the patients who met either OH criteria, the percentage of those with symptoms was small (33% of those with 20/10 and 44% of those with 30/15 mmHg; 16% and 13%, respectively overall). Symptomatic OH was associated with an upright mean blood pressure below 75 mmHg. A mean standing blood pressure <75 mmHg had a sensitivity of 97% and a specificity of 98% for detecting symptomatic OH. Conclusions Although the prevalence of OH in PD is high, not all patients have symptoms of organ hypoperfusion. A mean standing blood pressure below 75 mmHg appears to be a useful benchmark when deciding whether the benefits of initiating pharmacological treatment of OH outweigh the risks of exacerbating supine hypertension.

‘Under pressure’: is there a link between orthostatic hypotension and cognitive impairment in α-synucleinopathies?

“…In patients with PAF or MSA, BP reduction during head-up tilt was associated with reduced cerebral oxygenation measured by NIRS. S74 In PD, a mean standing arterial BP under 75 mm Hg was highly sensitive and specific for detecting patients with symptomatic OH, whereas only 50% of the patients who had a drop of either 20 mm Hg in systolic BP or 10 mm Hg in diastolic BP were symptomatic 20. This may indicate that a mean arterial pressure of under 75 mm Hg is likely below the lower threshold for cerebral autoregulation of blood flow in patients with α-synucleinopathies.…”

“…It is important to note, however, that classical symptoms of OH (ie, postural light-headedness) may be absent in PD patients who have objective postural drops in blood pressure (BP), and thus OH is under-recognised and under-reported 20. This may relate to either cognitive impairment confounding the ability of patients to report symptoms or to the reduced threshold in mean arterial pressure above which patients may not experience symptoms of OH in α-synucleinopathies 21…”

Droxidopa in neurogenic orthostatic hypotension

“…Symptoms of nOH can be non-specific, including fatigue and difficultly concentrating and may mimic the levodopa “off” state in PD patients. Conversely, patients may have difficultly distinguishing symptoms of nOH from other causes of lightheadedness [8]. Furthermore, nOH is frequently associated with progressive neurodegenerative disorders; failure to demonstrate long-term improvement could conceivably be due to worsening of the underlying neurodegenerative disorder rather than failure of the active agent.…”

“…OH increases the risk of falls and is an independent risk factor for mortality [6]. Treatment is complicated by the presence of supine hypertension, which occurs in up to 70% of patients with nOH [7,8]. …”

“…This usually occurs at a mean BP of 75 mmHg, corresponding to around 90/60 mmHg (systolic/diastolic) at heart level. [8] Symptoms disappear soon after the patient resumes sitting or lying and cerebral blood flow increases again. The chronic nature of nOH allows adaptive changes in cerebral autoregulatory mechanisms.…”