Linked Life Data

16940207

Source:http://linkedlifedata.com/resource/pubmed/id/16940207

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2006-9-22
pubmed:abstractText
Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only on the magnitude of wave reflection but also on wave shapes and timing of incident and reflected waves. More accurate measures are obtainable after separation of pressure in its forward (P(f)) and reflected (P(b)) components. However, this calculation requires measurement of aortic flow. We explore the possibility of replacing the unknown flow by a triangular wave, with duration equal to ejection time, and peak flow at the inflection point of pressure (F(tIP)) and, for a second analysis, at 30% of ejection time (F(t30)). Wave form analysis gave forward and backward pressure waves. Reflection magnitude (RM) and reflection index (RI) were defined as RM=P(b)/P(f) and RI=P(b)/(P(f)+P(b)), respectively. Healthy subjects, including interventions such as exercise and Valsalva maneuvers, and patients with ischemic heart disease and failure were analyzed. RMs and RIs using F(tIP) and F(t30) were compared with those using measured flow (F(m)). Pressure and flow were recorded with high fidelity pressure and velocity sensors. Relations are: RM(tIP)=0.82RM(mf)+0.06 (R(2)=0.79; n=24), RM(t30)=0.79RM(mf)+0.08 (R(2)=0.85; n=29) and RI(tIP)=0.89RI(mf)+0.02 (R(2)=0.81; n=24), RI(t30)=0.83RI(mf)+0.05 (R(2)=0.88; n=29). We suggest that wave reflection can be derived from uncalibrated aortic pressure alone, even when no clear inflection point is distinguishable and AI cannot be obtained. Epidemiological studies should establish its clinical value.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1524-4563
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
48
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
595-601
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Quantification of wave reflection in the human aorta from pressure alone: a proof of principle.
pubmed:affiliation
BMEYE BV, Academic Medical Centre, Suite K2-245, University of Amsterdam, Meibergdreef 9, NL-1105 AZ Amsterdam, The Netherlands. berend.westerhof@bmeye.com
pubmed:publicationType
Journal Article