TRANSVENOUS HEMODYNAMIC ASSESSMENT OF EXPERIMENTAL ARTERIOVENOUS-MALFORMATIONS - DOPPLER GUIDEWIRE MONITORING OF EMBOLOTHERAPY IN A SWINE MODEL

Background and Purpose A Doppler guidewire was used to monitor progres sive changes in draining vein flow parameters during experimental embo lotherapy in a swine arteriovenous malformation (AVM) model. Methods A microcatheter was positioned superselectively in the main arterial fe eder and main draining vein in each of 10 AVM models in swine. With us e of the Doppler guidewire, preembolization arterial and venous averag e peak velocities (APVs) and pulsatility indices were recorded. The de vice was left in the draining vein during transarterial particulate (i n 8 swine) or liquid adhesive (in 2 swine) embolization, and continuou s transvenous how during and after treatment was monitored. Periemboli zation Doppler flow parameters were correlated qualitatively with angi ographic changes in the nidus; Results Preembolization draining vein f low was pulsatile, with a mean APV of 38.9+/-13.7 cm/s. After emboliza tion, this changed significantly to a less pulsatile or nonpulsatile p attern, with a lower mean APV of 9.2+/-4.9 cm/s (P=.0001). A novel exp ression, the maximum minus the minimum peak velocity (MxPV-MnPV), was used in evaluating the transvenous Doppler spectra. This was reduced s ignificantly after embolization from a mean of 11.1+/-3.5 cm/s to 6.7/-2.5 cm/s (P=.0025). Objective periembolization hemodynamic changes w ere detected in the draining veins earlier than the visually subjectiv e angiographic changes within the nidus. Conclusions Transvenous Doppl er guidewire assessment of two parameters, APV and MxPV-MnPV, is usefu l in the hemodynamic evaluation of experimental arteriovenous shunting and may be used for future objective and quantitative monitoring duri ng endovascular AVM embolotherapy.