Abstract
The aim of this study was to evaluate the effects of pericardial effusion on coronary
artery bypass grafts and their patency using X-ray computed tomography (CT). Uncontrasted
CT of horizontal sections from the lower margin of the aortic arch to the left ventricle
was done at 5-mm intervals. In one cross-section of the pulmonary bifurcation level,
30 ml of a contrast media (lohexol 350) was injected at a rate of 3 ml/second into
the antecubital vein. All slices of uncontrasted CT were analyzed for the presence
or absence of effusion. The severity was expressed as the maximum value of the thickness
of effusion. CT was repeated about every 6 months postoperatively under the same conditions.
Selective angiography was also performed 7.1 ± 3.9 months postoperatively. A total
of 46 patients (mean age 57 years) underwent CT and angiography. A total of 95 grafts
were implanted: 90 saphenous veins and 5 internal thoracic arteries. Selective angiography
revealed that 79 grafts were patent and 16 were occluded. The first postoperative
CT (at 2.6 ± 2.1 months) showed the retention of effusion in all patients. The mean
maximum value was 1.0 ± 0.5 cm; there were no significant differences between patent
grafts (1.0 ± 0.5 cm) and occluded grafts (1.0 ± 0.5 cm). Occlusion was found in 10
grafts by the first CT (2.9 ± 2.7 months postoperatively) and another 6 grafts by
the second CT (11.3 ± 4.2 months). Thereafter, all grafts were patent. Previously
occluded grafts showed no cross-section images on uncontrasted or contrasted CT. Except
for two grafts, all patent grafts could be observed even without contrast enhancement.
The remaining two grafts were masked with effusion, but patency was confirmed by a
contrast media. In conclusion, retention of effusion does not affect the patency of
grafts. Occlusion occurs early after surgery, and grafts cannot be imaged on CT. Patent
grafts can be observed by uncontrasted CT, as well as contrasted CT, except where
a large amount of effusion is present.
