Absence of focal compensatory enlargement or constriction in diseased human coronary saphenous vein bypass grafts - An intravascular ultrasound study

Background No in vivo data are available on the occurrence of compensatory enlargement or vessel constriction in diseased human coronary saphenous vein bypass grafts (SVBGs). The aim of this intravascular ultrasound (IVUS) study was to examine to what extent lumen reduction is accompanied by (1) vessel wall thickening and (2) arterial wall constriction in SVBGs. Methods and Results We used IVUS to examine 43 SVBGs from 42 patients (32 men, 10 women; mean age, 72+/-5 years) 8 to 23 (11+/-4) years after SVBG. IVUS images were obtained with a 3.5F monorail ultrasound catheter with a 30-MHz frequency and were analyzed at the lesion site, the reference site, and an intermediate site. The lumen area was significantly (P<.01) decreased; the vessel wall area (SVBG cross-sectional area minus lumen area) and the plaque area (area within the external elastic lamina minus lumen area) were significantly (P<.01) increased from the reference site through the lesion site. However. SVBG cross-sectional area was the same at these three sites (24.0+/-8.1 versus 24.4+/-8.6 versus 24.5+/-8.6 mm(2), P=NS), and the external elastic lamina area was also quite constant in each vessel (17.8+/-6.0 versus 17.7+/-6.4 versus 17.6+/-6.2 mm(2), P=NS). Conclusions These in vivo IVUS data from human coronary SVBGs demonstrate that (1) no focal compensatory enlarge ment or vessel constriction occurred in stenotic segments compared with the reference segments and that (2) the absence of focal compensatory enlargement appears to be a potentially important factor in the progression of stenoses in coronary SVBGs.