The prognostic spectrum of left main stenosis.

Three-year survival for 163 consecutive medically treated patients with 50% or greater left main stenosis was 50%. Survival was significantly higher for patients with 50 to 70% left main stenosis (one and three-year survivals of 91% and 66%) than for patients with 70% or greater left main stenosis (one and three-year survivals of 72% and 41%). In fact, left main lesions of less than 70% were not associated with the increased risk usually attributed to patients with left main stenosis. A number of noninvasive and catheterization characteristics were significant predictors of survival for patients with 70% or greater left main stenosis. Noninvasive descriptors defined a low risk subgroup (one and three-year survivals of 97% and 74%) and a high risk subgroup (one- and three-year survivals of 59% and 25%). These observations have important implications both in assessing therapeutic interventions and in managing individual patients.