Classical orthostatic hypotension during tilt testing was primarily driven by an inadequate increase or a decrease in total peripheral resistance, followed by an excessive decrease in stroke volume.
Case-Control (n=160)
What are the relative contributions of total peripheral resistance, stroke volume, and heart rate to the blood pressure decrease during tilt testing in patients with classical orthostatic hypotension?
In classical orthostatic hypotension, an inadequate increase or actual decrease in total peripheral resistance is the primary hemodynamic driver of the blood pressure drop during orthostatic stress.
PURPOSE: We studied the relative contributions of total peripheral resistance (TPR), stroke volume (SV) and heart rate (HR) to low blood pressure in classical orthostatic hypotension (cOH) on group and individual levels. METHODS: We retrospectively analyzed tilt test records from cOH patients and age/sex-matched controls. We quantified relative effects of HR, SV and TPR on mean arterial pressure (MAP) with the log-ratio method. We studied relations of changes of HR, SV or TPR with the change of MAP across patients and variability of contributions of HR, SV and TPR to MAP. We also explored neurogenic vs. nonneurogenic causes. RESULTS: MAP responded to tilt with a decrease in patients ( n = 80) and an increase in controls ( n = 80). A too small TPR-increase contributed most to cOH, followed by a too large SV-decrease; both effects were partially corrected by a larger increase of HR. Only TPR changes consistently affected MAP change in patients and controls. TPR decreased almost exclusively in patients, most in those with severe cOH. Contributions of HR, SV and TPR to MAP did not differ between probable neurogenic and nonneurogenic causes. CONCLUSION: HR, SV and TPR all contributed to cOH, with a key role for TPR; a decrease of TPR was almost unique to patients and may be due to hyperventilation. The lack of differences between neurogenic and nonneurogenic causes needs further study.
Gagaouzova et al. (Wed,) conducted a case-control in Classical orthostatic hypotension (n=160). Classical orthostatic hypotension vs. Age/sex-matched controls was evaluated on Relative contributions of total peripheral resistance (TPR), stroke volume (SV), and heart rate (HR) to mean arterial pressure (MAP) change. Classical orthostatic hypotension during tilt testing was primarily driven by an inadequate increase or a decrease in total peripheral resistance, followed by an excessive decrease in stroke volume.