Stent Recoil Manifesting as Early Stent Thrombosis After Ultimaster Thin-Strut, Cobalt-Chromium Sirolimus-Eluting Stent Implantation

A 73-year-old man with renal failure requiring dialysis and stable angina underwent rotational atherectomy followed by implantation of a new sirolimus-eluting stent with bioresorbable polymer, Ultimaster^® (BP-SES) for severely calcified stenosis in the right coronary artery (RCA; Figure 1A–D). Intravascular ultrasound (IVUS) after BP-SES implantation showed a stent diameter of approximately 3.0 mm and well-expanded stent struts without evidence of incomplete stent apposition (Figure 2A–D). At 1 month after BP-SES implantation, the patient (who was taking both aspirin and prasugrel) presented with exertional chest pain, and was diagnosed with unstable angina with ST-segment depression. Emergency coronary angiography showed early thrombotic stenosis of the BP-SES with stent recoil (SR; Figure 1E–G). IVUS showed thrombus with partially low echo and SR without malapposed struts (Figure 2E–H; Movie S1). Optical coherence tomography showed residual thrombus overlying the stent struts (Figure 2I). Coronary angioscopy showed residual white and red thrombus, protrusion of yellow plaque and stent struts uncovered by neointima (Figure 2J). The BP-SES consists of an 80-mm-thick cobalt-chromium stent coated abluminally with biodegradable poly-DL-lactic acid and polycaprolactone copolymer, and has similar safety and efficacy to the current gold-standard everolimus-eluting stent.¹ This case, however, might provide insight into the mechanisms responsible for early stent thrombosis caused by SR in thinner-strut BP-SES under dual antiplatelet therapy. Severe calcification is a significantly stronger predictor of SR, and lesions with SR are associated with a higher rate of subsequent target lesion revascularization than those without SR.^2,3 A concern has been raised about possibly reduced radial strength leading to greater SR in thinner-strut cobalt-chromium stents than in stainless steel stents.⁴ In daily practice, careful attention should be paid to achieving better stent expansion by longer inflation or use of multiple inflations, especially in cobalt-chromium thinner-strut stents, which appear to be more susceptible to compressive external force compared with stainless steel stents.

Figure 1.

(A) Baseline coronary angiography (CAG) showing severely calcified stenosis in the right coronary artery (yellow arrow). (B,C) Index percutaneous coronary intervention with implantation of a new sirolimus-eluting stent with bioresorbable polymer, Ultimaster^® (BP-SES; 3.0 mm in diameter, 28 mm in length) after rotational atherectomy (1.5-mm burr). (D) Final CAG showing successful BP-SES implantation. (E) Magnified image without contrast agency after stent implantation with well-expanded stent struts (white arrows). (F) At 1 month after BP-SES implantation, emergency CAG showed early thrombotic stenosis (yellow arrow) of the BP-SES. (G) Stent recoil at the mid-portion of the implanted stent (red arrows).

Figure 2.

(A–H) Intravascular ultrasound corresponding to cross-section locations in the implanted stent. (A–D) Well-expanded stent struts without evidence of incomplete stent apposition after sirolimus-eluting stent with bioresorbable polymer, Ultimaster^® (BP-SES) implantation. (E–H) One month after BP-SES implantation: (E) no restenosis lesion at the proximal site; (F) stent recoil without malapposed struts; (G) thrombus with partially low echo; (H) no restenosis lesion at the distal site. (I) Optical coherence tomography showing residual thrombus overlying the stent struts (arrow). (J) Coronary angioscopy showing residual white and red thrombus, protrusion of yellow plaque and stent struts uncovered by neointima.

Disclosures

None.

Supplementary Files

Supplementary File 1

Movie S1. Intravascular ultrasound at an early thrombotic stenosis of the sirolimus-eluting stent with bioresorbable polymer, Ultimaster^®.

Please find supplementary file(s);

http://dx.doi.org/10.1253/circj.CJ-16-1088

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