Dual-Source computed tomography of the chest in the surgical planning of repeated cardiac surgery

When reoperative cardiac surgery is indicated, detailed, three-dimensional imaging of the thorax permits accurate depiction of cardiac anatomy and vascular structures potentially increasing the safety of the surgical procedure. We sought to evaluate the contribution of dual-source multidetector-row computed tomography (DSCT) of the heart and thorax in planning repeated open heart surgery.

Twenty-eight patients (mean age, 68 years) scheduled for repeated cardiac surgery who had undergone previous coronary artery bypass grafting (n=19) or cardiac valve replacement (8) or combined valvular and bypass surgery (1) underwent contrast-enhanced ECG-gated DSCT (Somatom Definition, Siemens Medical Solutions) of the whole thorax with a temporal resolution of 82 ms and a spatial resolution of 0.4 mm³. The indication for repeated surgery was bypass surgery (N.=6), valve replacement (16), combined bypass and valvular surgery (5) or other reasons (1). Assessment of surgical risk based on DSCT data were performed in terms of the relation of the ascending aorta and cardiac structures to the expected median sternotomy line, graft patency and anatomic course, and the degree of calcification of the ascending aorta and coronary arteries.

DSCT findings led to a change of surgical approach for 9/28 (32.1%) patients (non-midline incision, N.=3; surgery performed under circulatory arrest, N.=5; peripheral arterial cannulation before sternotomy, N.=1) and cancellation of surgery for 4/28 (14.3%) patients (heavy aortic and coronary calcifications impeding bypass surgery, N.=2; right heart or aortic aneurysm in close proximity to the sternum in high risk patients, N.=2). The planned surgical approach remained unchanged after DSCT for the remaining15/28 (53.6%) patients. Of 54 bypass graft conduits (20 arterial, 34 venous) visualized on DSCT in 20 patients after previous bypass grafting, 16 arterial and 24 venous grafts were patent, while 4 arterial and 10 venous grafts were occluded.

DSCT of the heart and thorax is an effective, non-invasive tool for the preoperative planning of repeated cardiac surgery. The technique provides significant information to modify the surgical approach and may increase the safety of the procedure.