Pitfalls and results of immediate angiography after off-pump coronary artery bypass grafting

Abstract

Background: We sought to determine the feasibility of off-pump coronary artery bypass grafting (OPCAB) in a consecutive series and prospectively assess the value of immediate post-operative coronary angiography.

Methods: All patients referred for coronary artery bypass grafting, within a four-month period, were approached as candidates for OPCAB. All 50 OPCAB patients were studied by immediate post-operative coronary angiography.

Results: The OPCAB procedure was feasible in 67% of patients (50/75). Five of 55 patients (9.1%) were converted to on-pump procedures, three for hemodynamic instability, and two because of deeply intramyocardial vessels. The other 20 underwent on-pump revascularization for anatomical and physiological reasons. The average age of OPCAB patients was 68.1 +/- 9.6 years; 26% were female, 74% male. Two (4%) were redo operations. Mean number of grafts was 2.9 +/- 0.8, 51 internal thoracic artery grafts (ITA), 17 radial artery grafts (RA), and 76 saphenous vein grafts (SVG). Angiographic graft patency was 90.2% for ITA, 88.2% for RA, and 96.1% for SVG. Interpretation of catheterization results was confounded by significant native and arterial graft spasm. Six of seven occluded arterial grafts and one of three SVG were probe patent at immediate reoperation (all had adequate flow by intra-operative doppler at the initial operation). Only two graft occlusions were noted in the 18 patients who did not receive protamine. The patency rate was 95.6% (131/137) when the probe patent anastomoses were excluded. Seven patients (14%) returned to the OR as a result of the catheterization findings; five to revise occluded grafts, one to improve the lie of a kinked SVG, and one to graft an intramyocardial intermediate ramus when an adjacent high diagonal was grafted instead (two of seven on-pump). All graft problems were found in the absence of hemodynamic instability or electrocardiogram changes. In-hospital mortality was 2% (1). Complications in survivors were atrial fibrillation in 12 patients (24.5%), permanent pacemaker in one (2%), endotracheal bleeding in one (2%), and take-back for bleeding in one (2%).

Conclusions: There were a significant number of unexpected arterial graft occlusions. The reversal of heparin and ITA spasm appeared to be contributory. All patients with occluded grafts had no signs of trouble. Interpretation of immediate post-operative catherization is difficult because of significant native vessel and graft spasm. It reliably determines patency but it's value is suspect for determination of long-term graft adequacy.