Partial angiotensin-converting enzyme inhibition during acute orthostatic stress in persons with tetraplegia.

Abstract

INTRODUCTION:

Individuals with tetraplegia rely on the renin-angiotensin system for orthostatic blood pressure control.

OBJECTIVES:

To determine the effect of partial angiotensin-converting enzyme (ACE) inhibition on heart rate (HR), active plasma renin (PR), and mean arterial blood pressure (MAP) during acute orthostasis in subjects with tetraplegia (n = 7) and nondisabled persons (n = 8).

METHODS:

Subjects were instructed to avoid caffeine and alcohol for 24 hours before testing and to report to the laboratory between 10 AM and 1 PM. Progressive head-up tilt (15 degrees, 25 degrees, 35 degrees, and 45 degrees) was performed on 2 separate days; Day 1: without ACE inhibition; Day 2: after intravenous (IV) infusion of enalaprilat (0.625 mg).

RESULTS:

HR was reduced during orthostasis in the tetraplegia compared with the nondisabled group (P < 0.0001), and was unaffected by ACE inhibition in either group. PR was not increased with orthostasis in either group, but was increased after ACE inhibition in both groups (P < 0.001). MAP was not affected by orthostasis in either group, but was reduced with ACE inhibition in both groups (P < 0.01). In the tetraplegia group, MAP was initially reduced after ACE inhibition, but was maintained thereafter with increasing angles of tilt, and no subject complained of symptomatic orthostatic hypotension.

CONCLUSION:

Subjects with tetraplegia were tolerant of an acute bout of orthostatic stress after partial ACE inhibition. This may have clinical relevance because of the increased prevalence of type 2 diabetes mellitus in this population and the use of ACE inhibitors for the treatment of progressive renal and cardiovascular disease.

• Authors: Jill M Wecht, Miroslav Radulovic, Joseph P Weir, Joanah Lessey, Ann M Spungen, William A Bauman
• Journal: The journal of spinal cord medicine (J Spinal Cord Med) Vol. 28 Issue 2 Pg. 103-8 ( 2005) ISSN: 1079-0268 [Print] England
• PMID: 15889697 (Publication Type: Clinical Trial, Controlled Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Angiotensin-Converting Enzyme Inhibitors
• Enalaprilat

Topics

• Adult
• Angiotensin-Converting Enzyme Inhibitors (pharmacology)
• Blood Pressure (drug effects)
• Cervical Vertebrae
• Dizziness (physiopathology)
• Enalaprilat (pharmacology)
• Humans
• Middle Aged
• Quadriplegia (etiology, physiopathology)
• Renin-Angiotensin System (drug effects)
• Spinal Cord Injuries (complications, physiopathology)
• Tilt-Table Test