Classification of left main coronary obstruction--feasibility of surgical angioplasty and survival after coronary artery bypass surgery.

Angiographies of 384 patients who had coronary artery bypass surgery because of left main coronary artery (LMCA) obstruction during 1970-1989 were reviewed by analysing the pathology, feasibility of surgical angioplasty and survival. Complete LMCA occlusion was found in 2%, proximal ostial stenosis in 9%, mid-shaft stenosis in 24%, circular stenosis in 25% and distal bifurcation stenosis in 40% of the patients. Patients with an ostial stenosis were younger, more often women with less coronary artery disease and less calcified obstructions. Surgical angioplasty could have been an option in 22% of the patients. Early mortality was higher in patients with (4.7%) than in those without (1.9%) LMCA obstruction. The relative risk (RR) of early death was 1.9 (95% CL 1.1-3.5) after adjustment for patient characteristics. Similarly, the RR at 10 years was 1.3 (95% CL 1.0-1.6). LMCA obstruction was associated with an early and long-term increased mortality after surgery compared to patients without LMCA obstruction.