We studied clinical and angiographic findings of 16 Korean patients who had isolated laft coronary ostial steonsis and compared them with those of the patients with non-ostial left main stenosis. The aim of this study is to find the characteristics of the patients with isolated left voronary ostial stenosis.

Medical records and coronary angiograms were reviewed. We divided the patients with left main stenosis into four groups by lesion location and associated lesion. Clinical and angiographic findings of each group were compared.

Twenty four patients(0.15%) had left coronary ostial stenosis and among them sixteen patients(0.1) had an isolated lesion. Their mean age was 48 years and 62% were female. Only 6 patients had coronary risk factors. Two patients were diagnosed as having Takayasu's srteritis. At treadmill exercise test, 7 out of 11 patients lhowed positive results at stage I. Eight patients had undergone surgical treatment.

Comoared with the patients who had non-ostial left main stenosis, left ostial group showed lower mean age, female preponderance and lower incidence of coronary risk factors. There was no difference in the results of treadmill exercise test and hemodynamic parameters.

Isolated left coronary ostial stenosis in Korea also predominantly occured in young female patients who had less risk factors as previous reports. But the incidence of this lesion and nonatherosclerotic origin seemed to be higher. And most of the patients with the left coronary ostial stenosis had isolated ostial stenosis.