Experimental determination of flow patterns of gelfoam emboli: safety implications

A major potential hazard of therapeutic occlusion of arteries by selectively injected Gelfoam pledgets is inadvertent reflux of nonopaque emboli into the aorta with resultant occlusion of other vessels. A simple method of injecting Gelfoam emboli through the standard nonoccluding arterial catheters customarily used for diagnostic arteriography was experimentally tested. The method incorporated certain safety features such as introduction of one embolus at a time using tuberculin syringes, low pressure injection technique, and frequent test injections of contrast to ascertain vessel patency. The results indicate that Gelfoam emboli can be safely and reliably employed using this technique, provided the catheter tip is properly positioned and emboli are only introduced as long as contrast test injections demonstrate rapid antegrade flow and continued patency of the artery. Once stasis or occlusion of most major branches are detected, blood flow in the catheterized artery has effectively ceased and further embolization is risky.