Management of Dislodged Coronary Stent Using Intravascular Ultrasound

Abstract Stent dislodgement is a rare but potentially lethal complication that can result in coronary embolization, emergent coronary artery bypass graft surgery, or death. Improvements in equipment design have drastically lowered the incidence of stent dislodgement and various retrieval techniques have previously been evaluated, but there have been no published reports on the utility of intravascular ultrasound (IVUS) for the management of dislodged or embolized stents. We report a case where IVUS imaging allowed precise location of the embolized stent, with subsequent entrapment using a newly deployed stent. The use of IVUS can possibly improve percutaneous management of dislodged stents, further reducing the need for surgical retrieval. Introduction Percutaneous coronary intervention with stents has significantly altered management of patients with coronary artery disease by improving clinical outcomes.1 A rare but potentially lethal complication is stent dislodgement, which can result in coronary embolization, emergent coronary artery bypass graft surgery, or death.2 Improvements in equipment design have drastically lowered the incidence of stent dislodgement from above 8% in the days of manually crimped stents to less than 0.5% with the universal use of premounted stents.2,3 Various retrieval techniques have previously been evaluated with a success rate as high as 86%, but there have been no published reports on the utility of intravascular ultrasound (IVUS) for the management of dislodged or embolized stents. Case A 51-year-old female with history of diabetes, hypertension, dyslipidemia and chronic obstructive pulmonary disease presented with anterior ST-segment elevation myocardial infarction (Figure 1). Coronary angiogram revealed a hazy, thrombotic plaque in the mid segment with occlusion of the distal segment of the left anterior descending artery (LAD) (Figure 2) as the culprit lesion for the clinical presentation. A CLS 3.5 Runway guiding catheter (Boston Scientific, Natick, MA) was used to engage the left coronary system and a 182-centimeter Choice intermediate guidewire (Boston Scientific) was used to cross the lesion. Mechanical aspiration was performed using a Pronto extraction catheter (Vascular Solutions, Minneapolis, MN) followed by AngioJet thrombectomy (Possis Medical, Minneapolis, MN) with only partial removal of thrombus (Figure 3). Balloon angioplasty with 2.5 x 15 millimeter Quantum Maverick monorail balloon (Boston Scientific) at 14 atmospheres was followed by deployment of 2.75 x 20 millimeter Liberte bare-metal stent (Boston Scientific) at 10 atmospheres. However, following stent deployment, there was poor distal contrast runoff despite serial balloon inflations (Figure 4). Review of the angiograms after withdrawal of the guidewire confirmed a dislodged stent in the proximal segment of the artery (Figure 5). Repeat coronary angiography with IVUS using Atlantis SR Pro catheter (Boston Scientific) demonstrated a free-floating, partially expanded stent in the proximal left anterior descending artery (Figure 6). After attempts to wire the unexpanded stent with the help of IVUS imaging were unsuccessful, the decision was made to crush the underexpanded stent with the deployment of a 3.5 x 16 millimeter Liberte bare-metal stent at 18 atmospheres in the proximal LAD as well as to treat the initial lesion in the mid LAD with another 2.75 x 20 millimeter Liberte bare-metal stent at 12 atmospheres. Final coronary angiogram (Figure 7) and IVUS (Figure 8) confirmed an adequately expanded new stent and crushed old stent in the proximal LAD along with good angiographic result in the mid to distal LAD. The patient tolerated the procedure well and was discharged home after an uncomplicated hospital course for post myocardial infarction management. Discussion The incidence of stent loss during PCI has decreased significantly since the advent of premounted stents. Eggebrecht et al3 reported an incidence rate of stent embolization of 0.9% per patient or 0.5% per stent implanted in a 5-year period, while Brilakis et al2 found an incidence of 0.32% in a 3-year period. Different retrieval techniques of unexpanded stents have been described,2–7 including use of myocardial biopsy and biliary forceps (curved finger-like projections that can be extended or retracted), two twisted guidewires (intertwined ends of two guidewires to trap stent), basket devices (helically arranged loops that can be expanded or collapsed), loop snares (movable wire that has a loop contained within an outer catheter), and balloon catheters (inflation within or distal to the lost stent); nevertheless, surgical removal is required in a few cases.2,3 The advent of IVUS imaging has played a significant role in enhancing our visualization of stent deployment. However, its function in management of dislodged stents has not been previously reported. Herein, we report a case where IVUS imaging allowed precise location of the embolized stent with subsequent entrapment using a newly deployed stent. The use of IVUS can perhaps improve percutaneous management of lost stents, further reducing the need for surgical retrieval. Contact the authors at jcgeorgemd@hotmail.com

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