Observation of the Suspected Sharp Structure Caused a Pinhole Balloon Rupture Using Optical Coherence Tomography and Coronary Angioscopy

Both optical coherence tomography (OCT) and coronary angioscopy (CAS) are excellent modalities to observe intracoronary structures. Although most coronary artery structures are identifiable by both modalities, some difficulty to assess structures may be present. We report a case of a 76-year-old male who presented with effort angina. Coronary angiography revealed a severe stenotic lesion in the distal right coronary artery (RCA), and hence, percutaneous coronary intervention (PCI) to the lesion was performed. We additionally performed post-dilatation with a noncompliant balloon after stenting, resulting in the balloon rupturing at only 4 atm. When observing the balloon, a pinhole rupture was confirmed. OCT revealed a high signal intensity sharp structure protruding into the lumen, considered to be the cause of the balloon rupture. CAS revealed that the protruding structure was a white–white yellow color. The stent could be expanded using a new noncompliant balloon without any balloon rupture. Postprocedural OCT and CAS showed that the protruding sharp structure disappeared and a part of the structure was pressed onto the lumen. Combining the OCT and CAS findings, we considered the structure might be a micro-calcified nodule or a cholesterol crystal. We hereby report and assess the sharp structure based on the OCT and CAS findings.