STEMI From Left Main Compression by Pulmonary Artery Aneurysm Diagnosed With IVUS.

BACKGROUND

Left main coronary artery compression (LMCo) by a dilated pulmonary artery is a rare but potentially fatal complication of pulmonary arterial hypertension (PAH).

CASE: An octogenarian man with asthma and PAH presented with dyspnea and developed pulseless ventricular tachycardia. Electrocardiogram showed ST-segment elevation in leads I, aVL, and V4 to V6. Angiography revealed 99% stenosis of the proximal left main trunk. Intravascular ultrasound (IVUS) showed slit-like compression without plaque. A 3.5- × 15-mm drug-eluting stent was implanted, restoring TIMI flow grade 3. Subsequent computed tomography demonstrated a 73-mm pulmonary artery adjacent to the left main trunk (pulmonary artery/aorta ratio: 2.28), confirming LMCo. Despite intra-aortic balloon pump and continuous hemodiafiltration support, the patient died on day 15 because of biventricular failure.

DISCUSSION: This case highlights IVUS in diagnosing extrinsic coronary compression. Although percutaneous coronary intervention restored flow, severe PAH contributed to poor outcome.

TAKE-HOME MESSAGE: IVUS is key for diagnosing LMCo. Percutaneous coronary intervention may help, but underlying hemodynamics dictate prognosis.