BACKGROUND: Intimal tear or dissection is a serious complication after coronary angioplasty,sometimes which may develop an acute ischemic event. We evaluate the factor that may predict the development of dissection after angioplasty. METHODS: To identify the factors that development of dissection after angioplasty, the data of 52 patients identified as having dissection with or without immediate vessel closure were examined. Follow-up coronary angiogram was obtained in 22 out of 58 lesions at mean 5.6 month after angioplasty. RESULTS: Intimal dissection developed 58 lesion(31%) out of 177 lesions in 122 patients after PTCA. Ischemic complications, defined as ischemic chest pain, myocardial infarction, the need for coronary bypass surgery occured in 5 patients(9.6%) out of 52 patients with dissections. Significant correlates of a development of dissection were the lesion morphology of type C(P<0.01), more tight diameter stenosis before PTCA(P<0.01), and right coronary artery(P<0.02), especially in the proximal portion (P<0.05). There were no significant correlations of clinical pictures, whether complex or simple angioplasty and PTCA in single vessel disease or in multivessel disease. Morphologic feature of dissection was type A(radiolucency) in 22(38%), B(filling defect)in 14(24%), C(extra-luminal "cap")in 8(14%), D(spiral dissection)in 5(9%), E(filling defect with delayded antegrade flow)in 7(12%) and F(total occlusion) in 2(3%). Twenty-two(38%) dissection out of 58 were obtained follow-up angiogram at mean 5.6 month. Angiographic restenosis occured in 9(41%) lesions, which included more type A dissections (7/9,78%) compared to lesions with dissection healing (3/13, 23%)(P<0.001) at follow-up. Thirteen lesions with dissection healing at follow-up included more B and C dissection(B;54%,C;15%)and E dissection in 1. Furthermoremore restenosis occurred more prevalent in the infarct-related artery(P<0.001) and left anterior decending coronary artery lesion(P<0.01). There was somewhat higher diameter residual stenosis after angioplasty (32+/-11% vs 26+/-10%) in the lesions with restenosis, but there was no statistical significance. CONCLUSION: Intimal dissection after angioplasty occurred in 58(31%) leisions out of 122(177leisions) consecutive patients underwent PTCA developments if intimal dissection after PTCA significantly correlated with the lesions if type C, more tight diameter stenois before PTCA and right coronary artery. At mean 5.6months follow-up,angiographic restenosis occured in 41% of dissections, which had more included type A(radiolucency)dissections, infarct-related artery and left anterior descending coronary artery leision.