Silent suppuration: an afebrile infected left anterior descending artery pseudoaneurysm with contiguous myocardial necrosis after drug-eluting stent implantation - a case report.

BACKGROUND: Infected coronary artery pseudoaneurysm is an uncommon but lethal complication of percutaneous coronary intervention, with a reported mortality approaching half of all cases. Fever and raised inflammatory markers are the dominant diagnostic clues, and their absence almost invariably delays diagnosis. Contiguous myocardial involvement by the suppurative process has, to our knowledge, not previously been described.

CASE PRESENTATION: A 46-year-old hypertensive Indian man presented with acute exertional chest pain four weeks after drug-eluting stent implantation in the left anterior descending (LAD) artery. He was afebrile and haemodynamically stable, with normal serial total leucocyte counts, C-reactive protein, and procalcitonin; multiple blood cultures remained sterile. Coronary angiography showed a saccular pseudoaneurysm at the proximal edge of the LAD stent, and ECG-gated CT aortography confirmed a 19 × 12 mm peri-stent contrast leak. 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) demonstrated intense uptake (SUVmax 18.0) in a paracardiac soft-tissue collection abutting the stent, raising the unsuspected diagnosis of infection. At urgent operation, frank pus was evacuated from the sac and had tracked into the adjacent epicardium and superficial myocardium, producing focal myocardial necrosis that required debridement. The stent was retrieved, the proximal LAD ligated, coronary endarterectomy performed, and revascularisation achieved with an in situ left internal mammary artery (LIMA) to LAD anastomosis. Cultures grew Pseudomonas aeruginosa. Recovery was uneventful and the patient remained well at three-month follow-up.

CONCLUSIONS: Infected coronary pseudoaneurysm can present with a silent inflammatory profile and may extend beyond the vessel wall into the surrounding myocardium. FDG PET-CT can be a decisive, and at times the principal, diagnostic test when conventional clinical and laboratory clues are absent. Surgical management must extend beyond sac exclusion and bypass to include debridement of contiguously infected myocardium, and benefits from arterial conduit revascularisation.