title: Incidence of and risk factors for perioperative optic neuropathy after cardiac surgery.
abstract: BACKGROUND
  Visual loss from optic neuropathy rarely occurs in the perioperative period in patients who have undergone nonocular surgery. We performed a retrospective, matched, case-control study to determine the incidence of perioperative optic neuropathy (PON) after cardiac surgery with the use of cardiopulmonary bypass (CPB) and to determine risk factors that may lead to this potentially devastating complication.
  
  
  METHODS
  Medical records of all patients undergoing cardiac surgery during a 9-year period were reviewed retrospectively to identify visual loss from acute unilateral and bilateral optic neuropathy during the perioperative period that had developed in patients. Data were collected from these patients and compared with data from control subjects matched for age, gender, risk factors for vascular disease, and type of surgery to determine the incidence of and potential risk factors for PON.
  
  
  RESULTS
  Of 9701 surgical patients requiring CPB, 11 patients (0.113%) with PON were identified. Although both the absolute and relative drop in hemoglobin during the perioperative period approached statistical significance, no other putative risk factors were identified.
  
  
  CONCLUSIONS
  The risk of PON associated with cardiac surgery in which CPB is used is low but substantial. The factors that lead to the condition remain unknown, although the presence of systemic vascular disease and both the absolute and relative drop in hemoglobin during the perioperative period seem to be important. Because PON often causes profound permanent visual loss, we recommend that patients, particularly those with systemic vascular disease, for whom cardiac surgery with CPB is planned, be made aware of this potential complication.
authors.affiliation: Neuro-Ophthalmology Unit, The Wilmer Eye Institute, Baltimore, Maryland 21287, USA.
authors.forename: Sachin D
authors.initials: SD
authors.lastname: Kalyani
authors.forename: Neil R
authors.initials: NR
authors.lastname: Miller
authors.forename: Li Ming
authors.initials: LM
authors.lastname: Dong
authors.forename: William A
authors.initials: WA
authors.lastname: Baumgartner
authors.forename: Diane E
authors.initials: DE
authors.lastname: Alejo
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Gilbert
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015142:Baltimore / Q000453:epidemiology; D006348:Cardiac Surgical Procedures / Q000706:statistics & numerical data*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000706:statistics & numerical data; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000453:epidemiology* / Q000209:etiology; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000453:epidemiology / Q000209:etiology