Publications de Nico Westerhof

Contribution of the Arterial System and the Heart to Blood Pressure during Normal Aging - A Simulation Study

Nikolaos Stergiopoulos, Elira Maksuti, Nico Westerhof

During aging, systolic blood pressure continuously increases over time, whereas diastolic pressure first increases and then slightly decreases after middle age. These pressure changes are usually explained by changes of the arterial system alone (increase ...

Public Library of Science2016

Systolic Hypertension Mechanisms: Effect of Global and Local Proximal Aorta Stiffening on Pulse Pressure

Nikolaos Stergiopoulos, Philippe Reymond, Nico Westerhof

Decrease in arterial compliance leads to an increased pulse pressure, as explained by the Windkessel effect. Pressure waveform is the sum of a forward running and a backward running or reflected pressure wave. When the arterial system stiffens, as a result ...

Springer US2012

RC time constant of single lung equals that of both lungs together: a study in chronic thromboembolic pulmonary hypertension

Nikolaos Stergiopoulos, Nico Westerhof

The product of resistance, R, and compliance, C (RC time), of the entire pulmonary circulation is constant. It is unknown if this constancy holds for individual lungs. We determined R and C in individual lungs in chronic thromboembolic pulmonary hypertensi ...

2009

Left ventricular hypertrophy induced by reduced aortic compliance

Nikolaos Stergiopoulos, Nico Westerhof

It was the aim of this study to investigate the long- term effects of reduced aortic compliance on cardiovascular hemodynamics and cardiac remodeling. ...

2009

Three- and four-element Windkessel models: assessment of their fitting performance in a large cohort of healthy middle-aged individuals

Nikolaos Stergiopoulos, Patrick Segers, Nico Westerhof

Lumped-parameter models are used to estimate the global arterial properties by fitting the model to measured (aortic) pressure and flow. Different model configurations coexist, and it is still an open question as to which model optimally reflects the arter ...

2008

Individualization of transfer function in estimation of central aortic pressure from the peripheral pulse is not required in patients at rest

Nikolaos Stergiopoulos, Nico Westerhof

Central aortic pressure gives better insight into ventriculo-arterial coupling and better prognosis of cardiovascular complications than peripheral pressures. Therefore transfer functions (TF), reconstructing aortic pressure from peripheral pressures, are ...

2008

Arterial pressure transfer characteristics: effects of travel time

Nikolaos Stergiopoulos, Nico Westerhof

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 v ...

2006

Nonlinear isochrones in murine left ventricular pressure-volume loops: how well does the time-varying elastance concept hold?

Nikolaos Stergiopoulos, Patrick Segers, Nico Westerhof

The linear time-varying elastance theory is frequently used to describe the change in ventricular stiffness during the cardiac cycle. The concept assumes that all isochrones (i.e., curves that connect pressure-volume data occurring at the same time) are li ...

2005