HEMODYNAMIC-CHANGES IN ARTERIAL FEEDERS AND DRAINING VEINS DURING EMBOLOTHERAPY OF ARTERIOVENOUS-MALFORMATIONS - AN EXPERIMENTAL-STUDY IN ASWINE MODEL

OBJECTIVE: Transcatheter assessment of changes in draining vein (DV) f low velocity has been proposed recently as a potentially useful proced ure for hemodynamic monitoring of the progression of embolotherapy in cerebral arteriovenous malformations (AVMs). We compared and contraste d changes in hemodynamic parameters of arterial feeders (AFs) and DVs during experimental AVM embolotherapy. METHODS: Carotid-jugular fistul a-type AVM models were surgically created in eight swine. Pre- and pos tembolization transcatheter mean AF and DV pressures, DV-time average spectral peak velocity, and AF and DV pulsatility indices were assesse d. An expression, the peak systolic velocity minus end-diastolic veloc ity (V-s - V-ed), was also used in evaluating the transvenous Doppler spectra. Pre- and postembolization hemodynamic parameters were compare d statistically. RESULTS: Pre-embolization DV flow was pulsatile (V-s - V-ed, 12 +/- 4.8 cm/s), with a mean DV velocity of 39.3 +/- 11.4 cm per second. Postembolization, this changed to a less/nonpulsatile patt ern (V-s - V-ed,V- 5.4 +/- 2.7 cm/s; P = 0.0035) with a lower mean DV- average spectral peak velocity of 7.0 +/- 3.1 cm per second (P = 0.000 1). The mean DV pressure was also reduced from 52.0 +/- 8.2 to 45.5 +/ - 8.7 mm Hg (P = 0.0023). The mean AF pressure increased from a mean o f 79.5 +/- 15.5 to 96.8 +/- 16.2 mm Hg (P = 0.0004). The DV pulsatilit y index values also increased from a mean of 0.3 +/- 0.2 to 1.1 +/- 0. 5 (P = 0.0003). Periembolization objective hemodynamic changes were de tected in the DVs earlier than were the visually subjective angiograph ic changes observed within the nidus. CONCLUSION: This preliminary stu dy indicates that transvenous assessment of average spectral peak velo city and wave pattern (V-s- V-ed) may be useful in the hemodynamic eva luation of AVM shunting. The convergence of these two parameters to a range less than 10 cm per second after nidus embolization may afford a theoretical advantage over AF pressure measurements when used for obj ective and quantitative monitoring of endovascular embolotherapy.