T.L.M. de Backer

Publications (2)2.8 Total impact

• Article: Ultrafiltration improves aortic compliance in haemodialysis patients.

  E H Y Ie, T L M De Backer, S G Carlier, W B Vletter, R W Nette, W Weimar, R Zietse
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  ABSTRACT: An elevated pulse pressure leads to an increased pulsatile cardiac load, and results from arterial stiffening. The aim of our study was to test whether a reduction in volume overload by ultrafiltration (UF) during haemodialysis (HD) leads to an improvement of aortic compliance. In 18 patients, aortic compliance was estimated noninvasively before and after HD with UF using a pulse pressure method based on the Windkessel model. This technique has not been applied before in a dialysis population, and combines carotid pulse contour analysis by applanation tonometry with aortic outflow measurements by Doppler echocardiography. The median UF volume was 2450 ml (range 1000-4000 ml). The aortic outflow volume after HD (39 ml; 32-53 ml) was lower (P=0.01) than before (46 ml; 29-60 ml). Carotid pulse pressure after HD (42 mmHg; 25-85 mmHg) was lower (P=0.01) than before (46 mmHg; 35-93 mmHg). Carotid augmentation index after HD (22%; 3-30%) was lower (P=0.001) than before (31%; 7-53%). Carotid-femoral pulse wave velocity was not different after HD (8.7 m/s; 5.6-28.9 m/s vs 7.7 m/s; 4.7-36.8 m/s). Aortic compliance after HD (1.10 ml/mmHg; 0.60-2.43 ml/mmHg) was higher (P=0.02) than before (1.05 ml/mmHg; 0.45-1.69 ml/mmHg). The increase in aortic stiffness in HD patients is partly caused by a reversible reduction of aortic compliance due to volume expansion. Volume withdrawal by HD moves the arterial wall characteristics back to a more favourable position on the nonlinear pressure-volume curve, reflected in a concomitant decrease in arterial pressure and improved aortic compliance.
  Journal of Human Hypertension 07/2005; 19(6):439-44. · 2.80 Impact Factor
• Source

  Available from: mit.edu

  Conference Proceeding: Total arterial compliance is a major determinant of peak oxygen uptake

  T.L.M. de Backer, S.G. Carlier, P. Segers, G. Armstrong, B. Haluska, N. Greenberg, T.H. Marwick, J.D. Thomas
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  ABSTRACT: Total arterial compliance (TAC), defined as dV/dP, is a major component of the arterial system. A decreased TAC increases left ventricular load and has a detrimental effect on coronary perfusion. We sought to assess the influence of TAC on the functional reserve (VO₂max). 14 patients (mean age 64±14y) with known or suspected coronary artery disease and 11 controls (34±5y) underwent supine bicycle exercise echocardiography. The audio Doppler signal output of the echocardiographic machine was digitized with a customized hardware and software interface simultaneously with carotid tonometry and ECG. TAC at rest was calculated by the pulse-pressure method (PPM). By step-wise forward multivariate analysis, independent predictors of VO₂max were: patient vs. control status, peak exercise cardiac output and TAC. The described PC-based acquisition system for tonometry and Doppler signals permits the assessment of ventricular function and arterial biomechanics
  Computers in Cardiology 2001; 02/2001