INTRAVASCULAR ULTRASOUND DETECTED CALCIFICATION OF CORONARY LESIONS AS A PREDICTOR OF DISSECTIONS AFTER BALLOON ANGIOPLASTY

Dissection after balloon angioplasty of coronary arteries may give ris e to an unfavourable early outcome. Compared with coronary angiography , intravascular ultrasound (IVUS) allows more detailed characterisatio n of dissections. We investigated the incidence and the type of dissec tions after balloon angioplasty in calcified coronary lesions. IVUS wa s performed in 43 patients with 48 lesions before and after percutaneo us balloon angioplasty. Significant calcification was defined as an ar e of more than 90 degrees with typical acoustic shadowing. Dissections were classified as type A when the media was not involved by the diss ection and as type B when media involvement had occured. In the group with significant calcification dissection was observed in 79 % of the cases vs. 38 % in the control group (p<0.03). Type B dissection was pr esent in 71 % of the dissections in the calcified lesions vs. 15 % in the control group (p<0.02). The balloon diameter and the ratio of ball oon area to vessel area was not different in both groups but the requi red pressure for the first complete balloon inflation was significantl y greater in the group with calcified lesions (9.46+/-3.6 atm vs. 6.65 +/-2.6 atm; p<0.001). Thus balloon angioplasty in calcified coronary l esions is more likely to lead to dissection which frequently involve t he media.