Study of Unprotected Left Main Stenting Versus Bypass Surgery (LE MANS Study)

The natural history and the results of pharmacological treatment in patients with severe narrowing of left main coronary artery show very poor prognosis (5 year survival less than 50%).

There is general agreement that surgical treatment improves 5 year survival in patients with left main coronary artery obstruction 3, however long term survival rate (15 year follow-up) is low in both groups (37% and 27% respectively in surgical and medical group). Median survival was longer in surgical group in general population (13.3 vs 6.6 years) , but there was no significant difference in patients with normal LV ejection fraction (14.7 vs 15 years).

With the advent of coronary stenting encouraging results were reported by several authors. There was high success rate 98-100% for elective procedures and in these series the mortality (for protected and non-protected left main) ranged from 0 to 3.4 %, and 6 month event free survival rate was 70-80%. Restenosis rate in stented LM varied from 10-22% for proximal LM to 40% for distal LM. Final minimal luminal area >=7mm2 post procedure, assessed by IVUS, predicted low restenosis rate of 7%, while the area below <7mm2 was connected with restenosis of 50%. Our and other experience showed that left main in-stent restenosis can be treated successfully with another percutaneous intervention (including endarterectomy and balloon angioplasty) as well as by surgical revascularization.

Six and 12-month survival rate depended on the LV function. Patients with LVEF>40% had in-hospital event free survival of 98% and 9-month event free survival of 86%, whereas patients with LVEF <40% had in-hospital and 9 month event-free survival of 67 and 22% respectively. Additionally, in patients presented with acute myocardial infarction or bail-out procedures, early and late results of LM stenting were not as good as for elective cases.

Our previously presented promising results of left main stenting is mainly related to proper technique of LM stenting (short inflations within LM, careful guiding catheter manipulation, stent selection), as well as very cautiously designed follow-up (every month visit for first six month, routine coronary angiography within 3-6 months after procedure). This initial experience gives us the backgrounds for a larger prospective randomized trial comparing elective surgical revascularisation and percutaneous intervention in patients with LM coronary artery disease. It is our impression that design and the delivery system of the new generation stent is uniquely suited to safely treat this difficult subset of patients. At the present time we would limit the study to the discrete lesions in proximal (ostial and mid) left main with reference luminal diameter >=3 mm. Based on published results of stenting under IVUS examination for such a lesion we estimate the restenosis rate to be well below 10%. As we expect, the survival and complication rate within one year in both group will be similar. Therefore our main concern is weather both treatment strategies will offer the same prevention of LV function, as well as improvement of functional capacity and coronary reserve in both groups in a period of 2-3 years.