Abstract
Stent thrombosis (ST) is the most dramatic complication of coronary stenting. Mechanisms of ST are multiple, including procedural and patient-related factors. A considerable burden of metal inside the coronary has been associated with ST as suggested by the higher rate of ST in case of multiple overlapping or complex two stents procedure in bifurcation lesions. However, occasional stent loss and failure to retrieve it may be a substrate of ST, especially if multiple layers of stent struts are incompletely crushed. Here, we describe a case of very late ST on a partially crushed stent previously lost inside the coronary circulation, using optical coherence tomography (OCT) for guidance during the procedure.
Stent thrombosis (ST) is the most dramatic modality of stent failure as it causes acute coronary syndrome in most cases. Mechanisms of ST are multiple, including procedural and patient-related factors . The burden of metal inside the coronary has been associated with ST as suggested by the higher rate of ST in case of multiple overlapping or complex two stents procedure in bifurcation lesions . However, occasional stent loss and failure to retrieve it may be a substrate of ST, especially if multiple layers of stent struts are incompletely crushed. Here, we describe a case of ST on a partially crushed stent previously lost inside the coronary circulation.
A 74 year-old woman was admitted to our emergency department with severe dyspnoea, inverted T-waves on antero-lateral EKG leads and increased Troponin T (0.12 ng/ml). She suffered from hypertension, dyslipidemia and had a previous history of coronary artery bypass (saphenous vein graft [SVG] for left anterior descending artery [LAD] and right coronary artery [RCA]) four years before, and percutaneous coronary intervention (PCI) with a bare-metal stent stent (BMS, Driver stent, Medtronic, Santa Clara, USA, 2.75 × 24 mm) implantation in the mid-left circumflex coronary artery (LCx) two years before. After PCI, the patient remained on aspirin 100 mg/d, clopidogrel 75 mg/d, beta-blockers, angiotensin-converting enzyme inhibitors and statins. Information about previous PCI procedure were available for us in the current admission thanks to the print report of the PCI performed two years before, however, the angiogram was not available. It was reported that a Driver stent (Medtronic, Santa Clara, USA, 2.75 × 24 mm) was initially deployed on the culprit lesion in the mid LCx at a level of a bend. Subsequently, the PCI was complicated by stent loss. This was apparently due to an attempt to deploy another Driver stent (2.5 × 18 mm) distally in order to seal a dissection caused by balloon dilatation of a lesion in the first obtuse marginal branch. While advancing through the bend the stent was stripped from its balloon, as described in the catheterization laboratory report of the other hospital. The operators decided to crush it with a balloon (3.0 × 20 mm Maverick NC, Boston Scientific Corporation, USA) at 18 atm. Distal lesion was eventually sealed by prolonged balloon inflation (2.5 × 20 mm Maverick NC, Boston Scientific Corporation, USA).
During the current admission, we performed coronary angiography that showed a radio-opaque image at the site of previous implanted stent in the mid-LCx, surrounded by a hazy image suggestive of coronary thrombus. As no other coronary stenoses that could explain the clinical presentation were found, we identified this lesion as the culprit lesion for Non-ST Elevation acute coronary syndrome ( Fig. 1 , panel A, B). A run of Frequency-Domain Optical Coherence Tomography (FDOCT) was performed at the lesion site using a non-occlusive technique with 20 mm/sec pullback C7 XR machine (Image wire and Image system, LightLab imaging Inc, Westford, MA, USA), showing ST. Of importance, OCT showed a crushed stent in the lumen with double layered struts of elliptical shape (with 2.1 mm separating the two opposite strut layers that led us to consider as a partial crushing), and with an image suggestive of thrombus around the stent. Of note, the crushed stent showed an area of malapposition, while the previous implanted BMS did not show malapposition.
