Determination of etiologic mechanisms of strokes secondary to coronary artery bypass graft surgery.
OBJECTIVE
Current research focused on stroke in the setting of coronary artery bypass graft (CABG) surgery has missed important opportunities for additional understanding by failing to consider the range of different stroke mechanisms. We developed and implemented a classification system to identify the distribution and timing of stroke subtypes.


METHODS
We conducted a regional study of 388 patients with the diagnosis of stroke after isolated CABG surgery in northern New England from 1992 to 2000. Data were collected on patient and disease characteristics, intraoperative and postoperative care, and outcomes. Stroke etiology was classified into 1 of the following: hemorrhage, thromboembolic (embolic, thrombotic, lacunar), hypoperfusion, other (subtype not listed above), multiple (>or=2 competing mechanisms), or unclassified (unknown mechanism). The reliability of the classification system was determined by percent agreement and kappa statistics.


RESULTS
Embolic strokes accounted for 62.1% of strokes, followed by multiple etiologies (10.1%), hypoperfusion (8.8%), lacunar (3.1%), thrombotic (1.0%), and hemorrhage (1.0%). There were 54 strokes with unknown etiology (13.9%). There were no strokes classified as "other." Nearly 45% (105/235) of the embolic and 56% (18/32) of hypoperfusion strokes occurred within the first postoperative day.


CONCLUSIONS
We used a locally developed classification system to determine the etiologic mechanism of 388 strokes secondary to CABG surgery. The principal etiologic mechanism was embolic, followed by stroke having multiple mechanisms and hypoperfusion. Regardless of mechanism, strokes predominantly occurred within the first postoperative day.
Likosky
Donald S
DS
Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA. Donald.Likosky@Dartmouth.edu
Marrin
Charles A S
CA
Caplan
Louis R
LR
Baribeau
Yvon R
YR
Morton
Jeremy R
JR
Weintraub
Ronald M
RM
Hartman
Gregg S
GS
Hernandez
Felix
F
Braff
Steven P
SP
Charlesworth
David C
DC
Malenka
David J
DJ
Ross
Cathy S
CS
O'Connor
Gerald T
GT
D002543:Cerebral Hemorrhage / Q000145:classification / Q000453:epidemiology / Q000209:etiology; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D006801:Humans; D020766:Intracranial Embolism / Q000145:classification / Q000453:epidemiology / Q000209:etiology; D009511:New England / Q000453:epidemiology; D015588:Observer Variation; D011183:Postoperative Complications / Q000097:blood / Q000139:chemically induced / Q000145:classification / Q000178:diet therapy / Q000453:epidemiology / Q000209:etiology; D011184:Postoperative Period; D012189:Retrospective Studies; D020521:Stroke / Q000145:classification* / Q000453:epidemiology / Q000209:etiology*; D013997:Time Factors