The hemodynamic pattern of the syndrome of delayed orthostatic hypotension

We investigated the hemodynamic mechanisms underlying the syndrome of delayed orthostatic hypotension (OH) and the hemodynamic effect of the treatment with leg compression bandages.

Non-invasive monitoring of systolic blood pressure (SBP), heart rate (HR), cardiac output (CO), stroke volume (SV), and total peripheral resistance (TPR) was performed during tilt testing in patients affected by delayed OH compared to age- and sex-matched controls. Thirteen patients (68 +/- 14 years) and nine controls (68 +/- 8 years) were studied.

Immediately after tilt-up, SBP progressively decreased in patients but not in controls. Symptoms developed at 100 +/- 7 mmHg. At the end of the test, SBP was significantly lower in patients than in controls. TPR progressively decreased in patients but not in controls. SV and CO did not change significantly. HR increased progressively in the patients until the end of the test and remained unchanged in controls. Active treatment with compression bandages avoided the decrease in SBP and TPR, while CO showed minimal variation.

In patients affected by delayed OH, the progressive decrease of SBP is associated with progressive decrease of TPR, while CO and SV show little variation; the compensatory increase in HR is insufficient to compensate for the decline in blood pressure.