Dual antiplatelet therapy (DAPT) with aspirin and a platelet P2Y12 receptor inhibitor has become the cornerstone for secondary prevention of coronary artery disease. Long-term DAPT is recommended after percutaneous coronary intervention (PCI) in patients with coronary artery disease to prevent future thrombotic events arising from the stent or untreated coronary lesions. However, antiplatelet therapy may have adverse consequences, the most common of which is gastrointestinal mucosal injury with ulceration and bleeding. The frequency of gastrointestinal complications increases with the duration of DAPT. Studies in patients treated with current generation drug-eluting stents have demonstrated that shortened DAPT regimens reduce the risk of bleeding events with small ischemic risk. However, the optimal duration of DAPT is still controversial. The extent to which an an abbreviated DAPT strategy reduces gastrointestinal mucosal injury has not been studied, principally due to the lack of sensitive, noninvasive measurements capable of detecting gastrointestinal injury.

Endoscopic examination of the gastric mucosa (gastroscopy) has high sensitivity and accuracy to detect gastrointestinal injury and bleeding. However, endoscopy is invasive and thus has no role in screening for sub-clinical gastrointestinal bleeding in patients undergoing PCI. Rather, endoscopy examinations are reserved for patients with active bleeding to identify the location of origin and etiology of the bleed. Moreover, gastroenterologists often refuse to perform gastroscopy in patients on DAPT given the risk of iatrogenic trauma with excessive hemorrhage. To minimize this risk, one or both antiplatelet agents often have to be discontinued for several days prior to the procedure, delaying the diagnosis while increasing the risk of stent thrombosis. Finally, upper endoscopy can only detect pathology related to the stomach and duodenum, as it does not visualize the remainder of the small intestine.

ANKON® magnetically controlled capsule endoscopy (AMCE) is a non-invasive, active controlled system which affords assessment of the stomach and entire small intestine. In the AMCE procedure, the patient swallows a capsule containing an endoscope which is actively maneuvered via magnetic control in the stomach, and then passes through the gastrointestinal track until its ultimate excretion. AMCE has several advantages compared to standard endoscopy. AMCE is noninvasive, painless and convenient, and can be re-administered as necessary. Patient acceptance of AMCE is likely to be substantially higher than standard endoscopy as the procedure involves only swallowing a capsule endoscope, without anesthesia or recovery time. Compared to standard endoscopy, AMCE provides more comprehensive detection of gastrointestinal pathology as it visualizes not only the stomach and duodenum, but the entire small intestine. Finally, discontinuation of antiplatelet drugs during AMCE is not necessary. Because of these advantages, AMCE can be used for screening of gastrointestinal mucosal lesions prior to clinical bleeding, including early detection of small areas of focal and concealed bleeding. Detection of preclinical gastric ulcerations or bleeding may be useful in directing preventative measures, whether gastro-protective therapies or DAPT discontinuation. A large-scale, randomized trial has confirmed that the sensitivity and specificity of AMCE for the detection of focal lesions of the gastrointestinal tract is similar to standard endoscopy. However, the potential utility of AMCE in patients receiving antiplatelet therapy after PCI has not been reported.

The current randomized study will evaluate AMCE as a tool to assess gastrointestinal mucosal injury and bleeding in patients on DAPT; evaluate the relative rates of gastrointestinal injury in patients on three different antiplatelet regimens; and establish a gastrointestinal mucosal injury scoring system which may prove useful in guiding optimal antiplatelet agent usage after PCI.