Natural history of left anterior descending coronary artery obstruction: Significance of location of stenoses in medically treated patients

Abstract

We examined the prognostic significance of an obstructive lesion in the proximal left anterior descending (LAD) coronary artery. Five‐year or longer followup data were examined from 311 patients with >70% obstruction of the LAD treated without surgery. Mortality was compared in subsets with lesions proximal to and distal to the first septal perforating artery. Survival curves were worse in patients with proximal than with distal LAD disease (p<0.05); lesion location remained a significant determinant of survival when ejection fraction, age, and sex were controlled using a Cox regression model. However, when patient subsets were examined, survival with proximal LAD disease was worse than with distal obstruction only in the presence of an associated right coronary artery lesion and an ejection fraction of less than 40% (p<0.01). Patients with proximal LAD plus right coronary lesions had a 5‐year mortality rate (34.08 ± 8.9%) that was not significantly (p>0.05) different from that of a group of 66 patients with >50% narrowing of the left main coronary artery (24.02d̊4.3%). Thus, proximal LAD disease is more significant than is a distal lesion only in the presence of right coronary obstruction. This twovessel combination results in a mortality rate as high as that associated with left main coronary artery obstruction. Copyright © 1985 Wiley Periodicals, Inc.