Post-mortem cast angiography in the diagnostics of graft complications in patients with fatal outcome following coronary artery bypass grafting (CABG)

Abstract

The advantages and limitations of a novel post-mortem angiographic method using solidifying silicone rubber and lead oxide as a contrast medium in detecting coronary artery graft complications on a routine basis were evaluated in a series of 223 consecutive patients with fatal outcome within 30 days following coronary artery bypass grafting (CABG). Of these patients, 166 (74.4%) were male and 57 (25.6%) female (mean age 61.9 ± 9). Coronary grafts totalled 660 (3.0 per patient) with 517 aortic and 838 coronary anastomoses. At autopsy, the rubber cast model of the grafts and coronary arterial tree was exposed by a bend scalpel and sites of possible complications were examined. Post-mortem angiographs were re-evaluated and compared with preoperative angiographs and dissection findings. By combining the findings of angiography and heart dissection, 122 (54.7%) of the 223 patients were found to have some type of complication of the graft or the anastomosis. The diagnostic sensitivity and specificity of postmortem angiography was 100% in assessing narrowing or twisting of the graft as well as narrowing of the aortal anastomosis, whereas these findings were revealed with difficulty by autopsy dissection only. In cases with correct x-ray projection, narrowing and occlusion of the proximal aortal and distal coronary anastomosis were also reliably revealed by angiography. In contrast, graft thrombosis was clearly overdiagnosed by angiography, leading to a lower specificity (84%) but high sensitivity (100%) in detecting this complication. Post-mortem angiography also failed to detect dissection of the wall of the graft or anastomosis. Technical problems with this angiographic method were due to too low perfusion pressure, too rapid polymerizing of the silicone rubber, leakage of contrast medium into the ventricles, or faulty x-ray projections. These results suggest that our post-mortem angiographic technique, yielding a permanent rubber- cast model of the graft and anastomosis site, improves the accuracy of diagnostics of postoperative CABG complications and eases postoperative autopsy dissection, which can now be directed to confirm suspected complications.