RANDOMIZED, CONTROLLED-STUDY OF VARIOUS AGENTS FOR ENDOSCOPIC INJECTION SCLEROTHERAPY OF BLEEDING CANINE GASTRIC VARICES

The purpose of this study was to compare the relative efficacy and technical ease of use of eight different agents for endoscopic hemostasis and obliteration of bleeding gastric varices in a canine model, as no comparative data are available on gastric variceal sclerotherapy. Large bleeding gastric varices in 20 heparinized dogs were randomized to endoscopic injection treatment with one of the following agents: cyanoacrylate; a 1:1:1 mixture of sodium tetradecyl sulfate 3%, ethanol 98%, and normal saline solution; ethanolamine oleate 5%; sodium morrhuate 5%; sodium tetradecyl sulfate 1.5%; polidocanol 1%; normal saline solution with epinephrine 1:10,000; or normal saline solution (control). The number and volume of injections and the time required to achieve complete hemostasis were evaluated; follow-up endoscopy was performed at 1 month to assess gastric variceal obliteration. Cyanoacrylate was the best agent overall in terms of immediate efficacy, low volume requirement, time required for initial hemostasis, and reduction of gastric variceal size. Cyanoacrylate, tetradecyl sulfate, and polidocanol were the most effective agents for reducing gastric variceal size. Epinephrine was effective for controlling induced or secondary bleeding caused by puncture of the gastric varices with the sclerotherapy needle during intravariceal injections. Ongoing studies are evaluating combinations of agents with different mechanisms of action, such as epinephrine (for vasoconstriction to minimize secondary bleeding) plus alcohol, and/or tetradecyl sulfate (for variceal thrombosis and sclerosis). In addition, different concentrations of alcohol as a single agent or combined with epinephrine should be evaluated because of the relatively low cost and wide availability of these substances.