Perioperative optic neuropathy in patients undergoing off-pump coronary artery bypass graft surgery

Perioperative optic neuropathy (PON) is a rare, but devastating complication following coronary artery bypass graft surgery (CABG). We performed a retrospective study of PON associated with off-pump CABG (OPCABG) to identify possible risk factors.

1442 patients underwent OPCABG over a 10-month period from October 2008 to August 2009; PON was identified in four (0.28%) patients. A retrospective review of the charts was done to identify the patient characteristics, pre-operative status, intra-operative details, and ophthalmic examination details. Friedman test was used to compare the hematocrit (Hct) and the mean arterial pressure (MAP) values across the three time periods: Pre-, intra- and post-operative periods.

All four patients were male, diabetic, and in the age range 51-69 years. All patients noted unilateral or bilateral severe visual loss in the immediate post-operative period, which was permanent. All the four patients had statistically significant decrease in the Hct (P < 0.039) and mean arterial blood pressure (P < 0.018) in the intraoperative and post-operative period when compared to pre-operative value.

PON is a rare but definite possibility in patients undergoing OPCABG. Diabetes mellitus may be a risk factor. Perioperative hemodynamic abnormalities like decrease in MAP and anemia may play a role in the development of PON in OPCABG.