Mechanism of pulsus bisferiens in thoracoabdominal thoracic aneurysms: Insights from wave intensity analysis.

Aortic pulsatile hemodynamics are important in various clinical conditions. Whereas the importance of wave reflections of the closed type in pulsatile hemodynamics has been extensively studied, less is known about the impact of reflections of the open type, in which reflected waves changes both direction and type (compression vs suction) compared to the incident wave. In this report, we present careful pulsatile hemodynamic analyses of a case in which prominent reflections of the open type occur in a patient with a thoracoabdominal aortic aneurysm, causing a highly abnormal proximal aortic and peripheral arterial hemodynamic pattern, known as pulsus bisferiens. Wave intensity analysis of central pressure-flow data demonstrated an early systolic forward-traveling compression wave followed by a prominent late systolic forward-traveling expansion wave, along with an abnormal prominent late systolic/early diastolic backward-traveling compression wave which produced a sharp rise in diastolic pressure, and was responsible for the pulsus bisferiens pattern.