When Two Lesions Collide: Coexisting Vasospasm and Atherosclerotic Disease Complicating Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction.

Timely reperfusion is central to the management of ST-segment elevation myocardial infarction (STEMI), but dynamic coronary processes such as vasospasm may complicate primary percutaneous coronary intervention (PCI). We present a 50-year-old male with hyperlipidemia, active tobacco use, daily nicotine vaping, and a family history of heart disease who presented approximately three hours after the onset of persistent chest pain, following three days of intermittent left arm pain radiating to the left shoulder. Initial troponin was negative. His initial electrocardiogram was unremarkable, but repeat electrocardiography 30 minutes later demonstrated inferior ST-segment elevation, prompting emergent transfer for primary PCI. Coronary angiography demonstrated a smooth proximal right coronary artery narrowing and a separate distal stenotic lesion. The proximal narrowing resolved completely after intracoronary nitroglycerin, and intravascular ultrasound showed no plaque or thrombus at that site. ST-segment elevations did not improve after intracoronary nitroglycerin alone. Despite nitroglycerin administration, the distal lesion persisted and was treated with balloon angioplasty followed by stent implantation, with a door-to-balloon time of 117 minutes. He was discharged on vasodilator therapy (initially nitrates, later transitioned to a calcium channel blocker due to intolerance). This case highlights how coronary vasospasm may accompany fixed obstructive disease during STEMI and create additional diagnostic complexity during primary PCI, with implications for lesion assessment, avoidance of unnecessary intervention, and post-PCI vasodilator therapy.