710-4 The Dimorphic Pathology of Vein Graft Lesions Effects Acute Procedural and Late Angiographic Outcomes

Abstract

In an attempt to understand better the pathology and results of transcatheter therapy of vein graft lesions, we performed intravascular ultrasound and quantitative angiographic analysis of 244 nonostial vein graft lesions. Preand post-intervention lesion site external elastic membrane (EEM), lumen, and plaque cross-sectional areas, calcium, and % cross-sectional narrowing (plaque/EEM area) were compared to a proximal reference site (most normal looking cross-section within 10 mm proximal to the lesion). Lesions were divided into two groups: 98 lesions with lesion EEM ≤ reference (“fibrotic”) ; 146 lesions with lesion EEM > reference (“ectatic”) . There was no difference in vein graft age, lesion length, or history of restenosis between the two groups. Fibrotic Ectatic p Reference EEM area (mm 2 ) 19.8 ± 7.3 18.6 ± 5.9 NS Reference lumen area (mm 2 ) 10.6 ± 4.4 10.6 ± 3.6 NS Reference plaque area (mm 2 ) 10.6 ± 10.0 8.0 ± 3.8 0.0052 Lesion site pre-intervention Angiographic % diameter stenosis 63 ± 20 60 ± 22 NS EEM area (mm 2 ) 16.1 ± 6.8 25.8 ± 10.6 <0.0001 Lumen area (mm 2 ) 2.6 ± 2.2 3.6 ± 2.7 0.0016 Plaque + media area (mm 2 ) 13.5 ± 6.4 21.9 ± 8.4 <0.0001 Arc of calcium (°) 61 ± 83 26 ± 54 0.001 Lesion/Reference plaque area 1.6 ± 0.7 3.1 ± 1.3 <0.0001 Lesion site post-intervention Angiographic %diameter stenosis 17 ± 17 12 ± 19 0.0903 Lumen area (mm 2 ) 6.7 ± 2.5 8.5 ± 2.9 0.0001 Follow-up angiographic %diameter stenosis 54 ± 33 35 ± 32 0.0329 16% of “fibrotic” had a lesion plaque area < reference. Importantly, (1) post-intervention minimum lumen areas were significantly smaller in fibrotic lesions, and (2) at follow-up the angiographic % diameter stenosis was significantly larger in fibrotic lesions. We Conclude: 40% of vein graft lesions may be classified as “fibrotic” . “Fibrotic” lesions have a decreased plaque burden and more lesion-associated calcium. Lumen compromise results from vessel retraction (?periadventitial fibrosis). In these lesions it may be more difficult to achieve optimal final lumen dimensions resulting in more frequent restenosis.