The Unholy Trinity: A Hybrid PCI Approach for Left Main Pseudoaneurysm, In-Stent Restenosis, and Acute Myocardial Infarction.

An iatrogenic pseudoaneurysm of the left main coronary artery (LMCA) originating from in-stent restenosis represents an exceedingly rare and life-threatening complication of percutaneous coronary intervention. When such a lesion presents as an ST-elevation myocardial infarction (STEMI), it creates a clinical scenario of extraordinary therapeutic complexity. We report the case of a 78-year-old man with a history of complex multivessel percutaneous coronary intervention who presented with an anteroseptal STEMI. His emergent coronary angiogram identified the culprit lesion as critical in-stent restenosis of a previously stented LMCA trifurcation, which was further complicated by a large pseudoaneurysm within the stent body. Following hemodynamic stabilization with an intra-aortic balloon pump, a novel hybrid percutaneous strategy was undertaken. The intervention involved meticulous high-pressure balloon angioplasty to address the restenosis, followed by the complete exclusion of the pseudoaneurysm using endovascular coil embolization. Finally, coronary perfusion was re-established by implanting a contemporary drug-eluting stent. Postprocedural optical coherence tomography confirmed the successful sealing of the pseudoaneurysm and optimal stent apposition. This case documents a uniquely catastrophic clinical event and appears to be the first documented instance of an iatrogenic LMCA pseudoaneurysm secondary to ISR presenting as a STEMI. Our successful management demonstrates that a hybrid technique integrating coil embolization with modern drug-eluting stent implantation is a viable and effective strategy for confronting this formidable clinical challenge.