Bleeding may occur into the digestive tract lumen from blood vessels contained in the digestive tract wall. Such bleeding is abnormal and may be associated with certain disease states and anatomical abnormalities. When bleeding occurs, it can be an acute emergency, with vomiting of blood or passage of blood from the rectum. In these cases, urgent endoscopic or surgical intervention is often necessary, along with blood transfusion, to avoid patient morbidity and mortality. Examples include a bleeding varix within the esophagus related to portal hypertension, an exposed bleeding vessel within a gastric or duodenal ulcer, or an arteriovenous malformation (collection of disorganized blood vessels) within the bowel that has ruptured.
Other bleeding lesions may present with chronic, less severe bleeding that results in chronic anemia and the need for serial endoscopic therapeutic interventions to cauterize visible abnormalities. Such cases often require chronic transfusion therapy, as the endoscopic interventions are not ideal to permanently halt bleeding. Examples include gastric antral vascular ectasia (GAVE), which is also known as watermelon stomach, for the appearance of its characteristic gastric lesions, radiation induced proctopathy and colopathy, portal hypertensive gastropathy (PHG), angiodysplasia, small arteriovenous malformations (AVM), and small bleeding ulcers. The common finding in many of these more chronic abnormalities is the presence of blood vessels in the digestive tract wall, specifically the mucosal and submucosal layers, that are larger than normal, more fragile than normal, more superficial than normal, tangled, disorganized, and/or exposed to the lumen of the digestive tract and therefore more traumatized than normal by passage of food or stool. Due to these combinations of features, these vessels tend to bleed into the lumen of the digestive tract on a chronic basis, thereby requiring chronic management.
Acute bleeding episodes of a magnitude where the patient is vomiting blood or passing blood from the rectum and is having cardiovascular effects are usually managed urgently with endoscopic or surgical therapy and blood transfusion. Typically, these events are associated with a large blood vessel that has ruptured and is bleeding profusely into the lumen. These lesions are visualized with an endoscope and may be injected with adrenalin to slow the bleeding, then cauterized with a small probe which is touched directly onto the vessel or may be cauterized with an electrified stream of argon gas. These probes deliver radiofrequency energy that rapidly heats the targeted focal vessel or tissue, and the blood vessels shrink and stop bleeding. Surgery is reserved for those patients with life-threatening bleeding that is not amenable to endoscopic therapy.
Chronic bleeding episodes, while causing long-term disability and the need for repeat therapy and transfusion, do not typically require urgent, life-saving intervention. Rather, these lesions are typically sought after with endoscopic examination when a patient presents with anemia of unknown cause. As described above, these lesions are identifiable and targetable with endoscopy. Cauterization is the standard therapy, in hopes of permanently eliminating the risk for bleeding. Unfortunately, in many cases, current techniques of cauterization fail to permanently eradicate these lesions, and bleeding returns. Factors contributing to unsatisfactory results with currently available cautery methods include the fact that lesions such as GAVE, radiation induced protopathy and colopathy, portal hypertensive gastropathy, and angiodysplasias tend to manifest as large, wide-spread lesions that are not amenable to a cautery technique which uses a small probe to press against the lesion. Even arteriovenous malformations tend to have high flow and larger surface areas, making them difficult to treat with small probes. Another likely reason for problematic and inconsistent results with conventional cautery methods relates to the presence of blood in the vasculature tissue at the time of cautery. Systems and methods, particularly non-surgical approaches or improvements on conventional cautery techniques would be welcomed in the field of treating sites of acute and chronic bleeding in the gastrointestinal tract.