MRI-induced stent dislodgment soon after left main coronary artery stenting.

S everal studies have shown the safety of MRI after coronary stenting; however, few of them included patients soon after stenting. In this report, we describe a case of MRI-induced stent dislodgment from left main coronary artery (LMCA) 2 weeks after stenting. A 56-year-old woman underwent coronary angiography for recurrence of angina 12 months after coronary artery bypass graft surgery. Coronary artery bypass graft surgery had been performed with left internal mammary artery grafted to left anterior descending artery and a saphenous vein graft to obtuse marginal branch for LMCA stenosis (Figure 1). The comorbidities of patient included hypertension, dyslipid-emia, diabetes mellitus, and prior neurosurgery for a pituitary adenoma. The repeat angiogram showed known stenosis in LMCA, nonobstructive disease of left anterior descending artery and right coronary artery, patent saphenous vein graft to obtuse marginal branch, and an occluded left internal mammary artery (Figure 2). After discussion, stenting of the LMCA with a 3.5×8 mm drug-eluting stent (Cypher; Cordis Corp, Markham, Ontario) was deployed after predilatation under intravascular ultrasound guidance (Figure 3). The patient underwent MRI of the head in a 1.5-Tesla scanner for surveillance of pituitary pathology 2 weeks after stenting. Follow-up angiography (Figure 4) was performed to investigate the symptoms of chest pain and assess stent patency. The implanted stent could not be visualized in the LMCA on angiography, and an intermediate residual stenosis was observed. A whole-body screening computed tomography was performed to locate the missing stent that was successfully identified in the proximal branch of the left iliac artery (Figure 5). In the absence of symptoms for arterial insuffi-ciency, no attempt was made to retrieve the embolized stent. Normal perfusion on repeat nuclear imaging confirmed that residual LMCA stenosis was not hemodynamically significant , and patient was continued on medical therapy with no clinical events occurring during long-term clinical follow-up. Discussion To our knowledge, this is the first report of coronary stent dis-lodgment related to an MRI procedure. Although the clinical implications of stent dislodgment can be serious, fortunately no adverse consequences were observed in this case as the stent migrated to a peripheral vessel in pelvis, an area with significant collateral circulation. Careful screening of patients undergoing MRI is mandated in patients with metallic objects and implants. 1 To improve safety, all implant devices are classified as MR safe, MR conditional, or MR unsafe based on the hazard posed in strong magnetic fields. The stents …