207. Simultaneous systolic waveform changes in uterine and ophthalmic artery Doppler in severe preeclampsie: A hemodynamic model based on increased pulse wave reflection

Abstract

Introduction In hemodynamics pulse wave (PW) propagation and reflection is well established and body reflection from the pelvic region contributes an accelerative impulse to systolic flow. Objectives In progressive preeclampsia (PE) ophthalmic artery (OA) Doppler shows increasing 2nd systolic peak (OA-P2) and peak ratio P2/P1. Simultaneously, in uterine artery (UtA) Doppler a systolic shoulder (UtA-S) may appear. We assume both changes indicate increased PW reflection. Methods In PW modelling UtA-S appearance indicates arrival of wave reflection and time to shoulder-onset (ΔT) corresponds to the 2-way travel time (2wTT) of a PW travelling with velocity c between pelvic and cardiac reflection sites with distance L: 2wTT = 2L/c (Eq. 1); L ≈ (aorta + common iliac artery). To test this model we performed UtA- and OA-Doppler in severe PE. When UtA-S was present, we compared measured ΔT with predicted 2wTT, using published data on distance L and PW velocity in PE. Seen from UtA, reflected waves travel ”back-and-forth”, and visa-versa, as seen from OA. As both additional path lengths agree, both waveform features will coincide. Results In 2017, six patients with severe PE finally entailed UtA-S and required delivery This agreement between observed (ΔT) and predicted (2wTT) temporal delay and mid-sytolic coincidence of UtA-S and OA-P2, substantiate the validity of the model. Furthermore P2/P1 exceeded 0.8 in all cases. Discussion Body reflection to cerebral circulation is well known in adults with cardiovascular dysfunction. But we are not aware of reports focused on PE-associated PW reflection to OA or UtA. Hemodynamic modelling shows evidence that UtA-S appearance and OA-P2 augmentation results from increased PW reflection in severe PE, indicating maternal cardiovascular dysfunction.