NEW YORK (Reuters Health) – High-resolution 3-dimensional magnetic resonance (MR) angiography accurately differentiates patent and occluded vein grafts after coronary artery bypass, and provides an assessment of the severity of vein graft disease, Dutch researchers report in Circulation: Journal of the American Medical Association for January 22.
Dr. Ernst E. van der Wall, from the Leiden University Medical Center, and colleagues used 3-D MR angiography to study 56 vein grafts from 38 patients who had recurrent chest pain after undergoing coronary artery bypass surgery. The patients also underwent coronary angiography.
The researches found that 18 grafts had luminal stenosis of 50% or more, 11 grafts had stenosis of 70% or more, and 6 grafts were occluded. Two blinded observers scored the MR angiograms looking for stenosis of 50% or more and 70% or more with a confidence level of 1 to 10.
For the two observers, the results of receiver-operator characteristic analysis showed an area under the curve 0.89 and 0.89 for identifying vein graft occlusion, 0.81 and 0.87 for stenosis of 50% or more and 0.82 and 0.79 for stenosis of 70% or more, the Dutch team found.
Agreement between the observers in identifying occluded grafts was 94%, for stenosis of 70% or more it was 82%, and for stenosis of 50% or more it was 72%, the investigators note.
Dr. van der Wall and colleagues conclude that "the novel finding in the present study is that high-resolution MR angiography enables assessment of vein graft stenosis severity with a fair diagnostic accuracy. This offers perspective for noninvasive screening of patients who present with recurrent chest pain after bypass surgery."