wasser

Case of the month

A 73 year-old woman admitted to hospital with a ST-elevation myocardial infarction. Six months previously she was treated with drug eluting stent (DES) implantation to the left anterior descending coronary artery (LAD) in the setting of a non ST-elevation acute coronary syndrome. One month earlier the patient started treatment with oral anticoagulation therapy because of new-onset atrial fibrillation and at this time point, dual antiplatelet therapy was reduced to clopidogrel alone.

Upon arrival in hospital the patient required emergency cardioversion for ventricular fibrillation. Emergency coronary angiography showed a thrombotic occlusion of the proximal part of the stent in the LAD (Figure 1). Intra-coronary imaging with optical coherence tomography (OCT) (Figure 2-3) performed after thrombus aspiration revealed evidence of restenosis at the proximal edge of the stent with signal characteristics suggestive of a lipid-core atherosclerotic plaque with rupture and thrombosis.

This case highlights the important role of intracoronary OCT in the assessment of patients with acute stent failure. It also demonstrates that neoatherosclerotic plaque development may provide the substrate for late stent failure. High-risk plaques such as thin-cap fibroatheromas can develop within the neointimal tissue layer, carrying risk of plaque rupture and thrombotic occlusion. The rapid development of plaque in this case (within 6 months after stenting) is noteworthy and seems to be a feature of neoatherosclerosis after DES as compared to after bare metal stents. The impact of possible residual non-obstructive disease at the proximal landing site of the original DES must also be considered. Moreover rapid disease progression suggests need for further optimization of this patientís modifiable cardiovascular risk factors. The role of aspirin discontinuation 1 month earlier is difficult to quantify but might conceivably have been contributory. The patient was discharged with triple therapy consisting of double antiplatelet therapy with aspirin and clopidogrel and oral anticoagulation with a vitamin K antagonist. A more strict control of cardiovascular risk factors was stressed.

Figure 1. Initial coronary angiography. Left descending coronary artery with occlusion (TIMI 0 flow) and luminal filling defect (a) characteristic of coronary thrombosis at the level of the previous implanted stent.

Figure 2 Optical coherence tomography (OCT) after thrombus aspiration. Longitudinal OCT view reveals evidence of restenosis at the proximal edge of the stent (a). Cross-sectional views showed the presence of stenosis at the proximal edge of the stent with intimal disruption (b) and residual thrombotic material (c). The proximal part of the stent is well apposed but displays in-stent restenosis (d) and neoatherosclerotic plaque characterized by lipid-laden appearance (e). After thrombus aspiration, a new DES was implanted proximal to the previous stent and partially overlapped, in order to cover the plaque at the proximal edge of the stent. The final result was good with no residual stenosis and TIMI III flow.

Contact

Prof. Dr Adnan Kastrati
Project Coordinator
German Heart Centre Munich
TU Munich

Per Larsen
Project Manager
German Heart Centre Munich
TU Munich

Dr Hans Sawade
Dissemination
neoplas GmbH