IVUS-guided rotational atherectomy for unexpandable paclitaxel-eluting stent: A case report and review of literature
A 76-year-old, non-diabetic and non-hypertensive female was referred to our emergency department with a diagnosis of acute coronary syndrome. Three months earlier, she underwent percutaneous coronary intervention (PCI) with a Taxus Liberte 2.75 × 24 mm stent (Boston Scientific Co. Natick, MA) implanted in the left anterior descending (LAD) artery for refractory angina, and had been on aspirin 100 mg and clopidogrel 75 mg a day. Upon arrival, her vital signs were stable, and there were no signs of heart failure.\nThe electrocardiographic findings and elevation of troponin-I (6.8 ng/dL) were consistent with non-ST elevation myocardial infarction. Transthoracic echocardiographic findings, including left ventricular function, were normal. Intravenous infusion of un-fractional heparin was initiated. Urgent coronary angiography revealed a well localized, hazy filling defect in the stented segment in mid-LAD (). Under the impression of late stent thrombosis, PCI with a non-compliant 3.25 × 12 mm balloon (Quantum balloon, Boston Scientific Co. Natick, MA) was performed. However, the balloon could not be fully expanded even with inflation pressure up to 28 atm. (). Intravascular ultrasound (IVUS) (Atalantis 2.9 Fr; Boston Scientific Co., MA) interrogation of the stented segment revealed an underexpanded stent (, ). The narrowest part of the ring was 1.47 mm × 1.49 mm in diameter. Under intravenous tirofiban infusion, rota-ablation was performed for 11 runs, five with a 1.5 mm burr and six with 1.75 mm burr. In each run, the rotation speed was 150,000 r/min and the burr was advanced very slowly for < 20 s to prevent speed deceleration < 3,000 r/min, and maintain adequate coronary flow with good myocardial Blush noted. After rota-ablation, IVUS images confirmed adequate ablation of the pre-existing stent and calcified layers (). Post-dilation with a non-compliant 3.25 × 12 mm balloon (Quantum balloon, Boston Scientific Co., Natick, MA) at 8 atm achieved full expansion of balloon (). Thus, a Taxus Liberte 3.5 × 32 mm stent was deployed at 14 atm, and a satisfactory result was documented by angiogram and IVUS imaging, respectively (, ). The patient's PCI course was uneventful and discharge followed a few days later on aspirin and clopidogrel. Follow-up angiography nine months later revealed < 30% instent restenosis ().