Intravascular ultrasound to assess aortocoronary venous bypass grafts in vivo.

In 20 consecutive patients (18 men and 2 women, aged 42 to 72 years) undergoing repeat coronary angiography because of new onset of angina pectoris 4 months to 11 years (mean 53 months) after aortocoronary saphenous venous bypass operation, the graft to the left anterior descending (n = 12), left circumflex (n = 4) or right coronary (n = 2) artery, or a diagonal branch (n = 2) was studied by both intravascular ultrasound and angiography. Sonographic images were obtained using a 4.8Fr catheter with a crystal mechanically rotated at 900 rpm; quantitative coronary angiograms were recorded in biplane projections. In 18 patients, qualitatively as well as quantitatively evaluable images could be recorded; no complications occurred. The venous wall in general appeared to be homogenous; there were no separate layers identifiable. Simultaneous ultrasound and angiographic measurements were performed at a total of 75 sites (2 to 6 per bypass). In 4 of these patients (10 of 75 sites), neither intravascular ultrasound nor angiography revealed any pathologic changes; these bypasses were classified as normal. At the remaining 65 sites, arteriosclerotic lesions were detected in each case by ultrasound, but at only 33 sites by angiography. Median wall thickness was 0.59 mm (95% confidence interval 0.54 to 0.63) in normal grafts and 1.02 mm (0.99 to 1.07; p less than 0.001) in diseased grafts. The cross-sectional luminal area determined by ultrasound correlated well with the angiographic assessment (r = 0.90; p less than 0.001), but the measured values were significantly higher (17 +/- 4 vs 14 +/- 4 mm2; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)