Applanation tonometry: a reliable technique to assess aortic pulse wave velocity in spinal cord injury.
METHODS
Within-subject repeated measures.


OBJECTIVE
To determine the intra- and inter-tester reliability of aortic pulse wave velocity (aPWV) measurements collected using applanation tonometry in individuals with spinal cord injury (SCI).


METHODS
Inpatient Rehabilitation Centre and outpatient Clinic in Vancouver, BC, Canada.


METHODS
Fifteen men and three women with traumatic SCI (age: 46±16 years; C3-L1; American Spinal Injury Association Impairment Scale A-D; 2-284 months post injury) participated in two testing sessions separated by an average of 2 days. During each testing session, aPWV measurements were collected in the supine position following 10 min of rest. Arterial blood pressure waveforms were collected simultaneously by two trained raters at the carotid and femoral arterial sites using applanation tonometry. Heart rate was continuously measured using a single-lead electrocardiogram, whereas brachial blood pressures were measured at 5-min intervals using an automated device.


RESULTS
Intra- and inter-tester aPWV measurements demonstrated almost perfect reliability with intraclass correlation coefficients of 0.91 and 0.98 (P<0.001), and coefficients of variation of 5.9% and 3.4%, respectively. The smallest detectable differences (SDDs) for intra- and inter-tester measurements were 0.9 m s(-1) and 0.6 m s(-1), respectively. There were no significant differences in heart rate or blood pressure between intra- and inter-testing sessions.


CONCLUSIONS
Applanation tonometry measurements of aPWV are reliable in individuals with SCI. In addition, the SDDs were smaller than a clinically relevant value, suggesting that this measurement is suitable for repeated measures study designs in SCI.
International Collaboration on Repair Discoveries (ICORD), Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
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Currie
International Collaboration on Repair Discoveries (ICORD), Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
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Hubli
1] International Collaboration on Repair Discoveries (ICORD), Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada [2] Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada [3] G. F. Strong Rehabilitation Centre, Vancouver, British Columbia, Canada.
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Krassioukov
D000208:Acute Disease; D001011:Aorta / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D001916:Brachial Artery / Q000503:physiopathology; D002339:Carotid Arteries / Q000503:physiopathology; D002908:Chronic Disease; D004562:Electrocardiography; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D063177:Pulse Wave Analysis / Q000379:methods*; D015203:Reproducibility of Results; D012146:Rest / Q000502:physiology; D013119:Spinal Cord Injuries / Q000175:diagnosis / Q000503:physiopathology*; D016683:Supine Position / Q000502:physiology