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.