Argon plasma coagulation (APC) in gastroenterology: Experimental and clinical experiences

Background: Diathermy procedures are indispensable in interventional endoscopy. Argon beam coagulation is an innovative no-touch electrocoagulation technique in which high-frequency alternating current is delivered to the tissue through ionized argon gas. Methods and patients: Before clinical application, we conducted in-vitro studies to investigate the depth and diameter of tissue coagulation in fresh operative specimens from the stomach, small intestine and colon. Five different power/gas flow settings between 40 and 155W and 2 and 7 l/min were used. The impact time (1-10s) and the incident angle of the probe (45 degrees and 90 degrees) were also varied. The maximum depth of necrosis was 2.4 mm, the maximum diameter 1.1 cm. No perforation occurred even in critical areas such as the colon and duodenum. We therefore performed argon beam coagulation in 66 consecutive patients. Two power/gas flow settings of 40 and 70W and 2 and 3 l/min, respectively, were used. The impact time and incident angle were varied individually. Results: In 49 of the 50 patients with oozing haemorrhage from angiodysplastic lesions, polypectomy sites, erosions or ulcers or oozing of blood due to vascular penetration by tumours, definitive haemostasis was achieved in one to two sessions. In all 11 patients with residual sessile adenoma tissue, complete removal was possible. Oesophageal patency was restored in all five patients with stenosing tumours. In one patient with angiodysplasia of the caecal pole, an asymptomatic accumulation of gas in the submucosa was observed which resolved spontaneously. In two patients with extensive oesophageal carcinoma, there was a transitory - also asymptomatic - accumulation of gas in the mediastinum and peritoneal cavity but no evidence of perforation. Conclusion: Argon plasma electrocoagulation is an effective and relatively low-cost alternative to laser therapy in gastrointestinal endoscopy.