Results
Over the period of study, 8271 patients underwent adult cardiac surgery
at our centre (excluding pulmonary endarterectomy and transplantation).
Of these patients, 165 (1.99%) experienced a postoperative stroke.
77.0% were early, being detected on waking with presence of focal
neurological signs or through not waking appropriately from sedation,
and the remaining 23.0% were delayed, occurring after recovery from
anaesthetic with later development of focal neurological signs.
The incidence of stroke varied significantly between the operation
categories (Table 1), being most prevalent for aortic surgery (8.14%),
and least prevalent for coronary artery bypass grafting (0.85%). In
comparison, over the same period 2541 patients underwent thoracic
surgical procedures with a stroke incidence of 0.2%. For aortic
surgery, 55.7% of strokes occurred in patients operated emergently for
acute type A aortic dissection. The median interval from operation to
stroke confirmation on CT was 2.5 days. The most common type of stroke
was ischaemic (93.4%), with intraparenchymal haemorrhage being much
less common (6.6% each) (Table 2). For the patients surviving to
discharge from our centre, the degree of disability was assessed using
the Modified Rankin Scale (Table 3)