ATHEROSCLEROTIC CORONARY LESIONS WITH INADEQUATE COMPENSATORY ENLARGEMENT HAVE SMALLER PLAQUE AND VESSEL VOLUMES - OBSERVATIONS WITH 3-DIMENSIONAL INTRAVASCULAR ULTRASOUND IN-VIVO

Objective - To compare vessel, lumen, and plaque volumes in atheroscle rotic coronary lesions with inadequate compensatory enlargement versus lesions with adequate compensatory enlargement. Design - 35 angiograp hically significant coronary lesions were examined by intravascular ul trasound (IVUS) during motorised transducer pullback. Segments 20 mm i n length were analysed using a validated automated three dimensional a nalysis system. IVUS was used to classify lesions as having inadequate (group I) or adequate (group II) compensatory enlargement. Results - There was no significant difference in quantitative angiographic measu rements and the IVUS minimum lumen cross sectional area between groups I (n = 15) and II (n = 20). In group I, the vessel cross sectional ar ea was 13.3 (3.0) mm(2) at the lesion site and 14.4 (3.6) mm(2) at the distal reference (p<0.01), whereas in group II it was 17.5 (5.6) mm(2 ) at the lesion site and 14.0 (6.0) mm(2) at the distal reference (p < 0.001). Vessel and plaque cross sectional areas were significantly sm aller in group I than in group II: (13.3 (3.0) v 17.5 (5.6) mm(2), p < 0.01; and 10.9 (2.8) v Netherlands 15.2 (4.9) mm(2), p < 0.005). Simi larly, vessel and plaque volume were smaller in group I (291.0 (61.0) v 353.7 (110.0) mm(3), and 177.5 (48.4) v 228.0 (92.8) mm(3), p < 0.05 for both). Lumen areas and volumes were similar. Conclusions - In les ions with inadequate compensatory enlargement, both vessel and plaque volume appear to be smaller than in lesions with adequate compensatory enlargement.