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The relationship between peripheral endothelial function and cerebrovascular reactivity to CO2 in older adults
Author(s) -
Brar Ikdip,
Robertson Andrew,
Hughson Richard L
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1194.18
Subject(s) - hypocapnia , brachial artery , medicine , peripheral , hyperventilation , reactive hyperemia , cardiology , middle cerebral artery , hypercapnia , cerebral blood flow , endothelial dysfunction , blood flow , anesthesia , blood pressure , ischemia , respiratory system
Reduced cerebrovascular reactivity to CO 2 contributes to a higher risk of cerebrovascular events. Studies on healthy and hypertensive middle‐aged adults have suggested the involvement of nitric oxide in CO 2 reactivity based on the relationship observed with peripheral reactive hyperemia. We tested the hypothesis that hyper‐and hypocapnic reactivity is correlated with peripheral vascular endothelial function assessed by flow‐mediated dilation (FMD) in healthy older adults. Methods Blood pressure, heart rate, end‐tidal PCO 2 , middle cerebral artery blood flow velocity (CBFV), as well as brachial artery diameter and shear rate, were monitored in 31 individuals (18 women; 72 ± 5 yrs). CO 2 reactivity was assessed by the relative change in CBFV during hypercapnia (5% CO 2 , 21% O 2 ) and hypocapnia (mild hyperventilation). Peripheral vascular function was measured by the relative brachial artery dilation after 5 min of forearm ischemia. Results Non‐parametric analyses suggested a possible relationship between cerebral and peripheral vascular function, such that a trend was observed between cerebrovascular reactivity and FMD in the hypocapnic range (r s =0.284, p=0.1), but not the hypercapnic range (r s =−0.22, p>;0.1). Conclusion Our study suggests only a weak relationship between peripheral endothelial function and reactivity to hypocapnia in older adults free of cardiovascular disease. Funded by CIHR .