Blood Flow Monitoring to Prevent Post-Polypectomy Induced Ulcer Bleeding

Inclusion Criteria: * Ambulatory patients, 35 years old or more and who are having: * elective, outpatient screening * surveillance colonoscopy for colon cancer or polyps * or being evaluated for abdominal pain or change in bowel habits ---or have a large polyp needing removal by EMR or ESD * Clinically the patient has to have a medical indication and recommendation by their primary care physician (PCP) or specialist to take: * daily anti-coagulants (Warfarin, low-molecular-weight heparin \[LMWH\] or a newer agent) * or an anti-platelet drug (aspirin as 81 mg or more, Clopidogrel, or newer agents) for PPIU's 10-14mm * or if not on one of these drugs, they must have a PPIU 15 mm * On colonoscopy, they are required to have: * benign appearing polyps and for 1 or more PPIU to be 10 mm in size (for the anti-coagulant or anti-platelet groups) * or 15 mm or larger for the PPIU group who do not have to be (but may be) on these drugs that can induce bleeding * In the case of bleeding from the PPIU during polypectomy, hemorrhage must be completely controlled Exclusion Criteria: * Inability or unwillingness to give written informed consent or to return to the investigators' medical centers for follow-up (FU) in the next 30 days, in case of delayed bleeding or other complications * Intrinsic bleeding disorder with a history of recurrent bleeding either after: * surgeries * angiography * or other invasive procedures * Significantly abnormal coagulation tests …