Unintentional Extraction of a Coronary Stent Deployed 4 Months Earlier during Cutting-Balloon Angioplasty for In-Stent Restenosi

Case Report. A 57-year-old male was admitted to our hospital with recurrent exertional chest pain for the past 2 weeks . Electrocardiography (ECG) showed significant ST-segment depression during exercise testing (100 Watt). Seven years previously, a high-grade stenosis of the right coronary artery (RCA) was treated by implantation of a bare-metal stent with a good result. Four months previously, the patient was admitted with unstable angina (negative troponin test). Two high-grade stenoses of the left anterior descending artery (LAD) were successfully treated by implantation of 2 bare-metal stents (Pro-kinetik [Biotronik, Berlin, Germany] 2.5–13 mm for the distal lesion and a Pro-kinetik 3.0–13 mm for the proximal lesion), with a good angiographic result (Figure 1A). The patients was in good general condition, but suffered from dyslipidemia and arterial hypertension. His daily medications included 100 mg acetylsalicylic acid, 40 mg simvastatin, 10 mg ezetimib, 2.5 mg bisoprolol and 5 mg ramipril.
Coronary angiography demonstrated a good long-term result in the RCA stent; however, in the LAD, a high-grade in-stent restenosis had developed within the proximal stent, resulting in significant flow reduction (Figure 1B). After predilatation of the stenosis, a cutting balloon (2.5–15 mm, Boston Scientific Corp., Natick, Massachusetts) was advanced into the stenosis, which was then inflated to 6 atm. After deflation, the cutting balloon could only be retrieved into the guiding catheter using increased traction. The guidewire was also removed during this maneuver. Inspection of the retrieved cutting balloon demonstrated that a stent was stuck to the blades of the cutting balloon (Figure 2).
Coronary angiography now showed total vessel occlusion at the site of the extracted stent. After recanalization with a guidewire, a major dissection at the site of occluded artery was identified (Figure 1C). Subsequent balloon angioplasty was followed by implantation of a paclitaxel-eluting stent (Taxus^® Liberté 3.0–24 mm, Boston Scientific) covering the entire region of the extracted stent and adjacent parts of the vessel (Figure 1D), rendering an excellent final result. Postprocedural echocardiography excluded pericardial effusion, and the following 2 days in the hospital were uneventful. Serum creatine kinase rose from a normal level prior to the procedure to 3.37 µkat/l ([normal: 0–2.95 µkat/l]; creatine kinase-MB 0.66 µkat/l [normal: 0–0.40 µkat/l]) 1 day after angioplasty without further symptoms of ischemia. The patient was discharged from the hospital angina-free.
Close inspection of the cutting balloon demonstrated complete removal of the stent which appeared to be elongated and thinned due to applied traction. Some struts seemed to be fractured, probably due to the extraction procedure. Retrospective analysis of the stent implantation procedure 4 months prior demonstrated a good final result after stent deployment, with complete expansion as assessed by angiographic criteria (Figure 1A).

Discussion. As a proof of principle, the present case illustrates that removal of a completely expanded coronary stent can happen. Taking into account that the coronary stent deployed 4 months earlier was fully embedded in the coronary vessel wall, the traction necessary to retrieve the cutting balloon in conjunction with the stent appeared to be surprisingly mild and was felt to be only slightly more than the upper limit during balloon retrieval in cases of very tortuous and calcified vessels. Nonetheless, severe damage to the coronary vessel may occur, leading to vessel closure, as happened in this case, or conceivably even tearing, perforating or rupturing of the coronary vessel. The slightly elevated levels of serum creatine kinase the day after the procedure may have been due to distal embolization during the procedure, which in this case, remained without further sequela.
Furthermore, this case demonstrates that blades of a cutting balloon may be stuck in a previously implanted coronary stent, precluding simple removal of the cutting balloon. According to the final angiogram during the initial stent implantation procedure, the stent appeared to be fully expanded. No further imaging modality, such as intravascular ultrasound, was used at that point, as it was not judged to be necessary. In retrospect, we postulate that some stent struts were not fully apposed to the vessel wall. Otherwise, the neointima that formed the in-stent restenosis 4 months later would have encompassed all of the stent struts, and would thus have made it impossible to capture them in the cutting balloon. However, this was not detectable by angiography during the initial stent implantation procedure.
In general, cutting balloon angioplasty is regarded as an acceptable treatment alternative for in-stent restenosis, and most studies have reported a similar or slightly improved rate of recurrence of restenosis in comparison with conventional balloon angioplasty.^5,6 Moreover, facilitation of the intervention appears to be another aspect, primarily due to less balloon slippage. The complication of a stuck cutting balloon within the coronary artery, as shown in this case, appears to be rare, but, when present, may even require surgical intervention.

References

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