Total obstruction of the left main coronary artery is a common cause of sudden death but is rarely seen in patients who survive to undergo diagnostic evaluation or treatment.

During twenty six-year period, we encountered 5 patients with chronic total obstruction of the left main coronary artery out of about 4,000 patients who underwent coronary angiography.

All patients have undergone coronary bypass surgery. These patients present with increasingly severe angina. A right dominat coronary anatomy is always found, usually with well-developed right-to-left collaterals. Left ventricular function was severely impaired in two patients out of five patients.

The results of surgical revascularization in our patients and others described in the literature can support the safety and efficacy of this approach.