Abstract
<title>Abstract</title> <p>Background Hyperacute stent thrombosis is uncommon but frequently catastrophic, and angiography alone cannot reliably distinguish thrombus from edge dissection, tissue prolapse, intramural haematoma or stent underexpansion. Most reports of this complication emphasise its management. We report a case in which the complication was largely self-inflicted, and in which the instructive content lies in how a reasonable initial interpretation became progressively harder to abandon. The report is presented as a self-audit rather than a technical success. Case presentation: A 61-year-old man presented with 2 h of chest pain and underwent primary percutaneous coronary intervention for anterior ST-segment elevation myocardial infarction. After implantation of a mid-left anterior descending artery stent, angiographic haziness appeared within and adjacent to the stent. It was interpreted as an unresolved mechanical complication and treated with two further stents. The haziness extended after each, culminating in abrupt vessel closure with Thrombolysis In Myocardial Infarction grade 0 flow and cardiogenic shock. Bailout aspiration thrombectomy retrieved a large red thrombus. A point-of-care activated clotting time, obtained for the first time only after haemodynamic collapse, was 150 s despite a weight-appropriate unfractionated heparin bolus of approximately 94 IU/kg. Intracoronary imaging was physically available but is not reimbursed for acute procedures under our national coverage scheme. Staged intravascular ultrasound on day 4 showed marked stent underexpansion, corrected by high-pressure noncompliant balloon dilatation with a final Thrombolysis In Myocardial Infarction grade 3 result. At 30 days the patient was free of angina with a left ventricular ejection fraction of 45%. Conclusions The proximate cause of this event was diagnostic rather than technical: an initial mechanical interpretation of haziness that each successive intervention reinforced instead of tested. An unverified anticoagulant effect and an underexpanded stent then converged to produce hyperacute thrombosis. Progressive angiographic haziness after stenting should function as a mandatory stop point: verify the activated clotting time, state the competing diagnosis and image the vessel where feasible before deploying another stent. These safeguards are inexpensive and carry proportionally greater weight in laboratories where routine intracoronary imaging is not economically available.</p>