Blood pressure recovery from Valsalva maneuver in patients with autonomic failure

Background: Blood pressure (BP) changes in response to the Valsalva maneuver (VM) reflect the integrity of the baroreflex that regulates BP, and the phases of VM are widely used indices of adrenergic evaluation. Objective: To study the BP recovery time (PRT) following termination of VM back to baseline to determine if it could be an additional and better indicator of adrenergic function. Methods: The authors evaluated three groups of patients with increasing degrees of adrenergic failure and an age-matched control group. Adrenergic failure was graded on the basis of systolic blood pressure (SBP) reduction to tilt: Group 1, orthostatic hypotension (OH; SBP ≥ 30 mm Hg); Group 2, borderline OH (BOH; 30 > SBP > 10 mm Hg); and Group 3, sympathetic sudomotor failure. Results: PRT was found to vary directly with severity of adrenergic impairment. PRT significantly correlated with previously utilized phases of the VM and baroreflex gain, with highest correlations with phases II_L (reflex vasoconstriction following initial fall in BP) and IV (BP overshoot following the VM). PRT extends the indices for the quantitation of adrenergic failure, since it will continue to parallel increasing adrenergic failure after phase II_L is lost and is a reliable index when II_L cannot be recorded. Conclusions: Pressure recovery time is a valuable index of adrenergic failure. It extends the value of the Valsalva maneuver by providing a quantitative index that is measurable in patients with severe adrenergic failure.