Stenting of unprotected left main coronary artery stenoses immediate and late outcomes

Author

J Am Coll Cardiol 1998; 31: 37-42 Abstract

OBJECTIVES: We examined the immediate and long-term outcomes after stenting of unprotected left main coronary artery (LMCA) stenoses in patients with normal left ventricular (LV) function. BACKGROUND: Left main coronary artery disease is regarded as an absolute contraindication for coronary angioplasty. Recently, several reports on protected or unprotected LMCA stenting, or both, suggested the possibility of percutaneous intervention for this prohibited area. METHODS: Forty-two consecutive patients with unprotected LMCA stenoses and normal LV function were treated with stents. The post-stent antithrombotic regimens were aspirin and ticlopidine; 14 patients also received warfarin. Patients were followed very closely with monthly telephone interviews and follow-up angiography at 6 months. RESULTS: The procedural success rate was 100%, with no episodes of subacute thrombosis regardless of anticoagulation regimen. Six-month follow-up angiography was performed in 32 of 34 eligible patients. Angiographic restenosis occurred in seven patients (22%, 95% confidence interval 7% to 37%); five patients subsequently underwent elective coronary artery bypass graft surgery (CABG), and two patients were treated with rotational atherectomy plus adjunct balloon angioplasty. The only death occurred 2 days after elective CABG for treatment of in-stent restenosis. The other patients (without angiographic follow-up) remain asymptomatic. CONCLUSIONS: Stenting of unprotected LMCA stenoses may be a safe and effective alternative to CABG in carefully selected patients with normal LV function. Further studies in larger patient populations are needed to assess late outcome.

Summary

The authors provide characteristics and clinical outcomes of 42 patients with preserved left ventricular function who underwent stenting of an isolated, unprotected left main stenosis. All but one patient were thought to be good candidates for coronary-artery bypass surgery but strongly preferred a percutaneous intervention. Stents were used electively in 38 patients and as bail-out therapy in four patients. Procedural success was 100% with no significant peripro-cedural complications and no stent thrombosis. Quantitative coronary angiography (QCA) revealed an increase in minimal luminal diameter from 1.1 mm to 4.2 mm. During follow-up, seven patients (17%) had symptomatic restenosis less than 2 months after the procedure. Among the 32 patients who underwent angiography at 6 months, restenosis occurred in seven patients. The only death occurred in a patient with in-stent stenosis who was referred for elective coronary bypass surgery.

Citation Count 77

Related References

1. O'Keefe Jr JH, Hartzler GO, Rutherford BD, etal. Left main coronary angioplasty: early and late results of 127 acute and elective procedures. Am J Cardiol 1989; 64: 144-147.

2. Ellis SG, Tamai H, Nobuyoshi M, et al. Contemporary percutaneous treatment of unprotected left main coronary stenoses: initial results from a multicenter registry analysis 1 994-1 996. Circulation 1997; 96: 3867-3872.

3. Silvestri M, Barragan P, Sainsous J, et al. Unprotected left main coronary artery stenting: immediate and medium-term outcomes of 140 elective procedures. J Am Coll Cardiol 2000; 35: 1543-1550.

4. Park SJ, Park SW, Hong MK, et al. Long-term (three-year) outcomes after stenting of unprotected left main coronary artery stenosis in patients with normal left ventricular function. Am J Cardiol 2003; 91: 12-16.

Key message

In carefully selected, low-risk patients with isolated stenosis of the left main coronary artery, percutaneous intervention with routine stenting may offer an alternative to coronary bypass surgery. However, patients are at significant risk of symptomatic restenosis and require close monitoring and routine angiography to identify recurrent ischaemia.

Why it's important

Left main lesions present a unique challenge to the interventional cardiologist. In the era of balloon angioplasty, patient outcomes were disappointing with high rates of symptomatic restenosis and the spectre of catastrophic acute closure. The arrival of coronary stents improved procedural success rates, but did not eliminate the risk of restenosis or stent thrombosis. In this setting, this case series provided an important first glimpse at both the promise and pitfalls of left main stenting. While initial procedural success was high, the 17% rate of restenosis presenting as unstable angina would give clinicians pause before adopting left main stenting as part of their interventional practice.

Strengths

There are two major strengths to this study. First, stents were implanted in all patients, which was not the case in other registries of left main stenting. Second, the authors almost exclusively enrolled patients who were also candidates for bypass surgery. Accordingly, patients were more similar to patients in clinical practice who are referred for coronary bypass surgery than what has been reported in other registries.

Weaknesses

This case series is far too small to determine the true risks and outcomes associated with stent implantation in unprotected left main stenosis. Although the authors excelled at identifying appropriate patients as evidenced by the high rate of procedural success, it may be difficult to replicate their decision-making process based on the description provided.

Relevance

For patients with significant stenosis of the left main artery, coronary bypass surgery offers a proven therapy shown to provide a survival advantage over medical therapy. In part due to the risks identified by Park and colleagues, the interventional community has remained appropriately reluctant to perform percutaneous interventions on left main disease in the absence of a relative or absolute contraindication to surgery. Nevertheless, pharmacological advances and the low restenosis rates achieved with drug-eluting stents may allow left main stenting to offer a safe and efficacious alternative to coronary-artery bypass surgery. At present, however, stenting of the left main remains largely a therapy of last resort, one usually employed in the setting of a cardiac emergency, severe co-morbid disease, or a patient's refusal to consider bypass surgery.

Chapter 7

Ancillary techniques in interventional

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