A case of Coronary Aneurysm After Implantation of a Sirolimus – Eluting Stent ( Cypher stent )

University Hospital “ St.Ekaterina”, Sofia,Bulgaria

Background

A coronary artery aneurysm ( CAA) is a dilatation that exceeds 1,5 times the diameter of the normal segment of the coronary artery and its formation is a rare complication of stenting with BMS( bare metal stents).Experimental studies suggest that Drug -eluting stents (DES) may induce toxic effects on the vessel wall because of incomplete stent apposition, aneurysm formation, and the potential for stent thrombosis or vessel rupture.

Case report-history

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• 66 year-old female with risk factors – arterial hypertension , dislipidemia and past smoker was referred to our hospital after ACS .

• Following medical stabilization, chest pain was exercise-induced with diffuse ischemic changes on ECG.

• On physical examination, she had an arterial pressure 140/90 mm Hg, a heart rate of 60 beats/min. Cardiopulmonary auscultation showed normal pulmonary status and insignificant mitral regurgitation.

• The echocardiogram showed a good global left ventricle ( LV) ejection fraction ( EF) of 56%, with septal hypokinesis and mitral regurgitation – I-II degree.

• Diagnostic coronary angiography revealed three vessel disease, including diffuse segments of RCA ,RCx and middle segment of LAD.

• The patient refused surgery.

• Since DES are not covered by National Health Fund the decision was made for only one DES in LAD.

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Procedure

Long lesion RCA was predilated with an undersized balloon ( 2,0/20) and 3,5/38 mm BMS ( Zeta) was implanted using 16

RCx lesion was treated with angioplasty using balloon 2,5/20 mm with 12 atm pressure with good final result

LAD lesion was predilated with balloon 2,5/20 mm and Cypher stent 3,0/33 mm was implanted with 18 atm

Follow-up coronary angiography and IVUS

Summary

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• Various hypotheses have been formulated to explain this complication such as positive regional vascular remodeling , plaque regression, the late dissolution of the thrombotic material captured by the stent struts, cell necrosis ,apoptosis and an allergic reaction to sirolimus
• Another concern is the possible toxic effects of the carrier polymer that is used as the drug platform.
  We suppose that it is the main reason in our case, because the aneurysm is localized beyond the stent. Lack of optimal endotelization at the stented segment 35 months after procedure, presence of an aneurysm distal from the stent could be due to allergic reaction combined with toxic effects and persistence of inflammatory effect locally as well as beyond the border of the DES.
• In summary we describe here a case with delayed development of a large coronary aneurysm after implantation of Cypher stent ,as a contrast there was no proliferation in the BMS and the site of balloon dilatation.
• Because of negative stress test, atypical complaints and TIMI III coronary flow in the LAD we decided to put the patient on double dose clopidogrel (150mg/d) for an unlimited time and regular physical control.

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