P6.06 CAN WE LEARN ANYMORE ABOUT ARTERIAL FUNCTION FROM THE VALSALVA MANOEUVRE? WAVE INTENSITY ANALYSIS CAN INFORM US ABOUT RESERVOIR FUNCTION

Abstract

Background: The Valsalva manoeuvre (VM) is a physiological manoeuvre capable of generating profound changes in venous return. Although its physiology has been extensively described, the predominant focus has been on dynamic effects on cardiac preload with subsequent impact on cardiac output. However, analysis of the dramatic changes seen in arterial pressure and flow during this manoeuvre offers valuable insight into arterial function. Methods: In 11 patients (9male, mean age 64 years), invasive measurement of pressure & Doppler flow velocity were made in the proximal aorta using sensor-tipped intra-arterial wires. Whilst recording, patients performed a controlled VM by blowing into a syringe. Calculation of pressure, aortic reservoir function and wave intensity were performed offline. Results: Peak systolic blood pressure fell on average by 24% during sustained VM (157±43mmHg to 122±48mmHg, p<0.0001). The peak reservoir pressure fell by an average of 65% (55±17mmHg to 20±13mmHg, p<0.0001). The aortic pressure waveform during sustained VM assumes that morphology typically seen peripherally (Figure). Conclusion: Prolonged VM is able to dramatically reduce both measured pressure and reservoir pressure in the proximal aorta and appears to produce a loss of this normal ‘cushioning’ effect. Is this simply a consequence of decreased stroke volume or are there other mechanisms involved? Pressure waveform recorded invasively in proximal aorta during sustained Valsalva manoeuvre.