Arterial pressure transfer characteristics: effects of travel time.
We investigated the quantitative contribution of all local conduit arterial, blood, and distal load properties to the pressure transfer function from brachial artery to aorta. The model was based on anatomical data, Young's modulus, wall viscosity, blood viscosity, and blood density. A three-element windkessel represented the distal arterial tree. Sensitivity analysis was performed in terms of frequency and magnitude of the peak of the transfer function and in terms of systolic, diastolic, and pulse pressure in the aorta. The root mean square error (RMSE) described the accuracy in wave-shape prediction. The percent change of these variables for a 25% alteration of each of the model parameters was calculated. Vessel length and diameter are found to be the most important parameters determining pressure transfer. Systolic and diastolic pressure changed <3% and RMSE <1.8 mmHg for a 25% change in vessel length and diameter. To investigate how arterial tapering influences the pressure transfer, a single uniform lossless tube was modeled. This simplification introduced only small errors in systolic and diastolic pressures (1% and 0%, respectively), and wave shape was less well described (RMSE, approximately 2.1 mmHg). Local (arm) vasodilation affects the transfer function little, because it has limited effect on the reflection coefficient. Since vessel length and diameter translate into travel time, this parameter can describe the transfer accurately. We suggest that with a, preferably, noninvasively measured travel time, an accurate individualized description of pressure transfer can be obtained.
Westerhof
Berend E
BE
BMEYE B.V., Academic Medical Center, Ste. K2-245, Meibergdreef 9, NL-1105 AZ Amsterdam, The Netherlands. berend.westerhof@bmeye.com
Guelen
Ilja
I
Stok
Wim J
WJ
Wesseling
Karel H
KH
Spaan
Jos A E
JA
Westerhof
Nico
N
Bos
Willem Jan
WJ
Stergiopulos
Nikos
N
D001011:Aorta / Q000502:physiology; D001132:Arm / Q000098:blood supply; D001158:Arteries / Q000033:anatomy & histology / Q000502:physiology*; D001366:Axillary Artery / Q000502:physiology; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001809:Blood Viscosity; D001916:Brachial Artery / Q000502:physiology; D004548:Elasticity; D006801:Humans; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D011673:Pulsatile Flow; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013348:Subclavian Artery / Q000502:physiology; D014664:Vasodilation