Coronary stenosis in Fabry disease with optical coherence tomography imaging presentation: a case report.

Background: Fabry disease (FD) is a rare X-linked lysosomal storage disorder and also a rare cause of coronary stenosis. We present a case of coronary stenosis in a 39-year-old man with FD, including optical coherence tomography (OCT) imaging findings. Case summary: A 39-year-old man was admitted with unstable angina. He had been previously diagnosed with FD through α-galactosidase A enzyme activity testing and genetic analysis. Coronary angiography (CAG) revealed 90% stenosis in the proximal left anterior descending artery (pLAD). The pre-procedural CAG-based fractional flow reserve (caFFR) was 0.57, and the CAG-based index of microcirculatory resistance (caIMR) was 14.4. Drug-coated balloon angioplasty was performed, achieving post-procedural stenosis of 0%, with caFFR improving to 0.86 and caIMR decreasing to 9.4. He had no traditional atherosclerotic cardiovascular disease risk factors. Although CAG indicated 90% stenosis of the pLAD, OCT imaging did not demonstrate typical atherosclerotic or fibrocalcific plaques. However, based on the patient's clinical features, OCT findings, and previous literature, we could not definitively determine the specific aetiology of the coronary stenosis (FD, coronary atherosclerosis, or both). During a 2-year follow-up, he remained angina-free. Discussion: Although OCT may aid in differentiating FD-related coronary involvement due to its high resolution and ability to detect FD-compatible changes, it cannot reliably determine whether the fibrous plaque morphology and loss of layered architecture are attributable to FD-related coronary pathology or premature atherosclerosis, representing a fundamental imaging limitation.