Background: Repeat open heart surgery is associated with an increased risk of injury to old conduits and cardiac structures. To reduce this risk, we evaluated the contribution of multidetector computed tomography angiography in planning repeat cardiac operations.
Methods: Fifteen patients who had previous coronary artery bypass grafting procedures underwent retrospective-gated computed tomographic angiography with a 16-slice multidetector computed tomography. Relation of the grafts to the expected median sternotomy line, graft patency and anatomic course, possible aortic cannulation and cross-clamp sites, distances between the right ventricle to the sternum, and calcification of the ascending aorta were assessed.
Results: Multidetector computed tomography demonstrated 45 conduits (mean, 3 +/- 1.1); 18 arterial grafts and 13 saphenous vein grafts that were patent, and 2 internal mammary artery grafts and 12 saphenous vein grafts that were occluded. Significant narrowing was shown in 3 of the patent internal mammary arteries and 4 of the patent saphenous vein grafts. Adherence of the right ventricle, left internal mammary artery, and saphenous vein graft to the sternum (0 to 3 mm in the midline) was demonstrated in 8, 2, and 1 patients, respectively. Two patients had a heavily calcified aorta. During surgery, all multidetector computed tomographic findings were confirmed. Three aspects of the operative plans of 4 patients were modified according to multidetector computed tomographic findings: median sternotomy approach (3 patients), cannulation site (2 patients), and myocardial preservation technique (3 patients). On the basis of multidetector computed tomographic evaluations, surgery was cancelled in 2 patients in whom repeat operation was judged to be associated with increased risk: 1 patient, scheduled for coronary artery bypass grafting, had an extremely calcified aorta, and the other, scheduled for aortic valve replacement, had grafts that were adherent to the sternum.
Conclusions: Multidetector computed tomography is a new noninvasive tool for three-dimensional preoperative assessment of complex cardiac and graft anatomy. Our initial experience suggests that it may provide information to warrant modifying surgical planning, thus contributing to the safety of reoperative heart surgery.