A Dissection Within a Dissection: Iatrogenic Left Main Coronary Artery Dissection Complicating Spontaneous Coronary Artery Dissection-Related Myocardial Infarction.

Spontaneous coronary artery dissection (SCAD) is an important cause of myocardial infarction in young women. Coronary instrumentation may worsen the dissection, particularly during percutaneous coronary intervention. A 39-year-old woman presented with a posterior ST-segment elevation myocardial infarction due to a Saw type I SCAD of the second marginal artery. During coronary angiography, guidewire manipulation and contrast injection precipitated an acute iatrogenic dissection of the left main coronary artery (LMCA) extending into the left anterior descending and circumflex arteries, resulting in hemodynamic collapse. Emergency stenting of the left main and circumflex arteries restored stable coronary flow. The initial lesion was managed conservatively and showed near-complete healing at three weeks. This case highlights the propensity for iatrogenic complications in SCAD owing to arterial wall fragility, reinforcing the need for a cautious, stepwise interventional approach. In SCAD, early recognition and limiting coronary manipulation are essential. When an LMCA compromise occurs, rapid stenting is lifesaving, while the original dissection lesion should subsequently be managed conservatively.