Effect of internal maxillary arterial occlusion on nasal blood flow in swine

Objectives: The precise effects of therapeutic occlusion of the internal ma xillary artery (IMA) on distal nasal mucosal perfusion are unknown. A bette r understanding of these effects has important implications regarding the r ationale and expected efficacy of certain therapeutic interventions for epi staxis management. The authors developed an animal model to assess these is sues. Study Design: The effects of "proximal" and progressively more "dista l" occlusions of the IMA on nasal mucosal blood flow (NBF) were assessed in anesthetized swine using continuous laser Doppler flowmetry. The levels of arterial occlusion were selected to simulate clinical therapeutic occlusio ns used for the management of epistaxis, Methods: Nineteen swine were enter ed into one of four experimental groupings: proximal IMA occlusion using pl atinum micro-coils (n = 6), mid-grade distal IMA occlusion with polyvinyl a lcohol particulate (PVA) suspensions (300 to 500 microns, n = 5), high-grad e distal IMA occlusion with polyvinyl alcohol particulate suspensions (50 t o 150 microns, n = 5), and sham control (n = 2). Results: Alo embolizations resulted in acute decreases in average NBF hom 120 mL/min per 100 g to 40 mL/min per 100 g (P <.05 for all groups). NBF returned to baseline in all t hree treated groups within 2 to 8 days after therapeutic embolization, depe nding on the level of occlusion (coils, 2 d; mid-grade PVA, 2-3 d; high-gra de PVA,8 d). Followup angiography showed recanalization and collateralizati on as possible methods of reestablishing NBF. Conclusions: This study suppo rts the rationale for performing distal IMA occlusion with transarterial pa rticulate embolization, in order to provide a longer period of time of dimi nished NBF. This theoretically should promote hemostasis within an injured portion of the nasal mucosa by decreasing perfusion pressure within the cap illary bed. However, the benefits of distal IMA embolization must be balanc ed against potential ischemic complications, as may be more commonly seen w ith high-grade particulate embolization.