Left main coronary artery stenosis occurs in 3–5% of patients undergoing coronary angiography. Percutaneous treatment has been limited by major adverse cardiovascular events during the follow-up period. Studies suggest bare metal stents have restenosis rates of 20–30%.¹ Recent studies suggest de novo left main (LM) stenting in the drug-eluting stent (DES) era is safe and effective, with restenosis rates of 5–20%.^2–4
       Traditionally, treatment for LM in-stent restenosis has been coronary artery bypass surgery. There are limited data on percutaneous treatment for LM stenosis, and almost no data on the treatment of LM in-stent restenosis with DES. We present a case of a 56-year-old male who underwent treatment of LM in-stent restenosis with DES.

       Case Report. A 56-year-old male with a history of angina was referred to the cardiac

Figure 1a

Shallow LAO (A) and RAO caudal; LAO = left anterior oblique; RAO = right anterior oblique; LAD = left anterior descending artery.

catheterization laboratory for further evaluation. He was found to have a heavily calcified 80% proximal and a 70% mid-left anterior descending (LAD) stenosis, and was considered for coronary artery bypass surgery (Figures 1A and B). The patient refused surgery and requested percutaneous treatment for his coronary disease. Rotational atherectomy was performed, followed by intravascular ultrasound to assist in appropriate stent-sizing. The patient was already receiving aspirin and clopidogrel prior to the procedure, and was administered intravenous unfractionated heparin and eptifibatide at the start of the procedure. Ultimately, a 2.5 x 23 mm sirolimus-eluting Cypher™ stent (Cordis Corp., Miami, Florida) was implanted in the mid vessel, and a 3.5 x 28 mm Cypher (SES) in the proximal vessel, with slight stent overlap. During post-dilatation inside the stent, a dissection flap and thrombus became apparent within the distal LM artery, felt to be caused by the guide catheter. The patient’s LM artery subsequently occluded, and cardiopulmonary arrest ensued. He underwent rapid balloon angioplasty of the LM to restore flow, after which a 4.0 x 16 mm Express2™ bare metal stent (Boston Scientific, Natick, Massachusetts) was placed in his LM at 14

Figure 1b

(B) view showing proximal LAD stenosis, without appreciable LM stenosis. LAO = left anterior oblique; RAO = right anterior oblique; LAD = left anterior descending artery.

atmospheres. A bare metal stent (BMS) was used due to concern at that time about the

Figure 2a

Completion of first procedure, with placement of a BMS in the LM and a second BMS in the proximal LCx, shown in the LAO caudal view (A) ; LM = left main; BMS = bare metal stent.

utilization of SES in thrombotic lesions — a concern which is no longer held. An intra-aortic balloon pump was placed. Plaque shift was noted in the left circumflex artery (LCx), compromising the ostium. Thus a 3.0 x 23 mm bare metal Zeta stent (Guidant Corp., Indianapolis, Indiana) was placed in the proximal LCx at 14 atmospheres using a T-stent technique. The kissing balloon technique was employed in the LAD and LCx, with excellent results (Figures 2 A and B). The patient’s CK-MB rose to 10.4 ng/ml (normal = < 6 ng/ml), and his troponin rose to 10.5 ng/ml (normal = < 0.40). Echocardiography was performed, revealing an ejection fraction of 50%.
       The patient did well clinically, and presented for a follow-up angiogram 5 months later. Angiography and intravascular ultrasound (IVUS) showed 50–60% in-stent restenosis of the distal LM artery, with 60% ostial stenosis in the LAD, and 80% ostial in-stent restenosis in the LCx (Figures 3 A–C). The proximal and mid-LAD (where the SES had been placed) were free from restenosis, with IVUS revealing that the SES did not extend into the LM, but began 1–2 mm into the LAD. The patient was again considered for surgery because of restenosis, but percutaneous coronary intervention was ultimately undertaken, using the stent crushing

Figure 3a

Multiple views, including shallow LAO (A), LAO caudal (B) and RAO caudal views (C), showing in-stent restenosis of the LM and proximal LCx. Additionally, IVUS imaging (not shown) revealed significant restenosis of the distal LM extending into the ostium of the LAD, and likewise confirmed significant restenosis in the ostium of the LCx.

technique. A 3.5 x 20 mm paclitaxel-eluting Taxus^® stent (Boston Scientific) was placed, spanning the proximal LM into the proximal LAD, and a 2.75 x 20 mm Taxus stent was placed across the

Figure 2b

Completion of first procedure, with placement of a BMS in the LM and a second BMS in the proximal LCx, shown in the RAO caudal view (B). LM = left main; BMS = bare metal stent.

ostium of the LCx, with approximately 2 mm remaining in the LM (Figure 4). The LCx stent was first deployed at 14 atmospheres, followed by removal of the LCx catheter and wire. The LAD stent was then deployed at 14 atmospheres, crushing the LCx stent against the wall of the LM artery. The LCx was rewired and progressive dilatations were performed at the ostium of the LCx. Finally, the kissing balloon technique was employed, with excellent results (Figures 5 A and B).
       The patient continued to do well clinically. He returned to work as a law enforcement officer and remained asymptomatic. He returned for follow-up angiography at 9 months, and was found to have no significant restenosis (Figures 6 A–C). At 14-month follow up, he completed 13 minutes of a Bruce protocol treadmill exercise test, without symptoms or ECG changes, and therefore was not referred for further follow-up angiography. He continues on aspirin and clopidogrel at this time due to concern about possible late stent thrombosis, given the location and number of stents he received.

Discussion
       This case demonstrates the potential benefit of treatment of LM restenosis with DES. DES have been shown to lower rates of restenosis as de novo treatment of LM stenosis compared to BMS.³ Additionally, DES appear to be effective treatment for in-stent restenosis of BMS.⁵ To date, there have been only a few references in the literature concerning treatment of LM

Figure 4

RAO caudal view shows positioning of two DES in anticipation of deployment utilizing a crush stent strategy. DES = drug-eluting stent.

restenosis with DES, but none have had 9-month angiographic follow up.^3,4 There are no other reports on treatment of in-stent restenosis involving BMS in a LM with 2 DES utilizing the crushing stent technique. Future large studies will be needed to determine if treatment of LM restenosis with DES will be as

Figure 3b

LAO caudal (B)

safe and effective as coronary artery bypass surgery. We utilized the crushing stent technique to

Figure 5a

Shallow LAO (A) and RAO caudal views (B) after deployment of DES in the LM and proximal LCx, with final kissing balloons.

approach this bifurcation situation; however, the optimal strategy for treatment of bifurcation lesions (i.e., one versus two stent strategies, and various two-stent strategy options) is not known. Studies are under way to address the optimal application of DES in the setting of bifurcation lesions.

Figure 5b

RAO caudal view (B) after deployment of DES in the LM and proximal LCx, with final kissing balloons.

       In summary, we report the successful treatment of in-stent restenosis within the left main coronary artery with implantation of a DES, with excellent short- and long-term results.

Figure 3c

and RAO caudal views (C), showing in-stent restenosis of the LM and proximal LCx. Additionally, IVUS imaging (not shown) revealed significant restenosis of the distal LM extending into the ostium of the LAD, and likewise confirmed significant restenosis in the ostium of the LCx.

Figure 6a

Shallow LAO (A), LAO caudal (B) and RAO caudal views (C) showing 9-month follow-up angiogram, free of significant restenosis.

Figure 6b

LAO caudal view (B)

Figure 6c

and RAO caudal view (C) showing 9-month follow-up angiogram, free of significant restenosis.

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2. Park SJ, Kim YH, Lee BK, et al. Sirolimus-eluting stent implantation for unprotected left main coronary artery stenosis. J Am Coll Cardiol 2005;45:351–356.
3. Valgimigli M, van Mieghem CA, Ong AT, et al. Short- and long-term clinical outcome after drug-eluting stent implantation for the percutaneous treatment of left main coronary artery disease. Circulation 2005;111:1383–1389.
4. Chieffo A, Stankovic G, Bonizzoni E, et al. Early and mid-term results of drug-eluting stent implantation in unprotected left main. Circulation 2005;111:791–795.
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