Incidence and risk factors for early postoperative cognitive decline after coronary artery bypass grafting

Ieva Norkienė¹, Robertas Samalavičius¹, Irina Misiūrienė², Kotryna Paulauskienė³, Valmantas Budrys⁴, Juozas Ivaškevičius¹

¹Clinic of Anesthesiology and Intensive Care, Faculty of Medicine, Vilnius University, ²Vilnius University Hospital Santariškių Klinikos, ³Institute of Hygiene, Vilnius, ⁴Clinic of Neurology and Neurosurgery, Faculty of Medicine, Vilnius University, Lithuania

Key words: cognitive dysfunction; neurological complications; coronary artery bypass grafting.

Summary. Background. The aim of our study was to evaluate the incidence of early postoperative cognitive decline (POCD) and determine perioperative risk factors as well as the impact of asymptomatic cerebral vascular lesion on the development of neurocognitive complications.

Materials and methods. A total of 127 consecutive adult patients undergoing on-pump coronary artery bypass grafting were studied. Neuropsychological testing was performed the day before surgery and 7–9 days after operation. Stepwise logistic regression analysis determined independent predictors of POCD.

Results. The incidence of postoperative cognitive decline was 46% (n=59). Patients in the POCD group were older (P=0.04) and had an increased prevalence of asymptomatic carotid artery stenosis (P=0.0001). POCD was associated with longer time in surgery (P=0.018), inotropic support intraoperativelly (P=0.02) and during postoperative period (P=0.008). Patients in the POCD group had an increased incidence of postoperative bleeding (P=0.037), delirium (P=0.016) and stayed in hospital for a longer period (P=0.007). Age of more than 65 years (OR, 2.7), asymptomatic carotid artery stenosis of more than 50% (OR, 26.89), duration of surgery of more than 4 hours (OR, 4.08), postoperative mechanical ventilation of more than 6 hours (OR, 3.33), and stay in an intensive care unit for more than 3 days (OR, 3.38) were significant independent predictors of cognitive decline.

Conclusions. Increased age, preoperative prevalence of craniocervical atherosclerotic lesions, longer time in surgery, longer stay in an intensive care unit and mechanical ventilation time were found to be the risk factors for developing postoperative cognitive decline.

Correspondence to I. Norkienė, Clinic of Anesthesiology and Intensive Care, Faculty of Medicine, Vilnius University, Šilt­na­mių 29, 04130 Vilnius, Lithuania. E-mail: ievanork@gmail.com

Received 11 November 2009, accepted 8 July 2010