Embolic Stroke As a Sequela of Cardiopulmonary Bypass

Abstract

Tha pathophysiology of brain injury in patients undergoing cardiopulmonary bypass remains unclear despite several decades of inquiry. The advent of noninvasive high-resolution brain and cerebrovascular imaging by magnetic resonance, computed tomography, and pulsed Doppler ultrasonography now permits in vivo assessment of pathophysiological mechanisms. Neuroradiographic and carotid duplex studies were performed in patients who developed neurological deficits following cardiopulmonary bypass. Among 30 symptomatic patients undergoing magnetic resonance or computed tomography brain scans, 18 (60%) had findings of acute ischemic injury. Embolic infarction was evident in 14 (78%) of these 18 patients. Watershed injury was the predominant finding in a single patient, while findings consistent with global anoxia were present in another patient. Carotid atheroemboli were excluded as a possible source of embolism in 11 patients whose carotid duplex studies were unremarkable preoperatively as well as in 3 further patients whose neuroradiographic findings did not correspond with their moderate carotid disease. It is concluded that infarction due to noncarotid embolism is the primary pathophysiology of neurological deterioration following cardiopulmonary bypass.

Study design validation for consolidating global with focal neurological events in cardiac surgery stroke risk factor analyses

“…Several patients exhibited both encephalopathy and focal deficits which were categorized according to the more prominent aspect. Eighteen of the 30 symptomatic patients in whom neuroimaging was obtained showed evidence of acute infarction or hemorrhage with a predominantly embolic etiology for which the detailed neuroimaging analysis and cerebrovascular topographic mapping of the typically multifocal and multicerebrovascular territory lesions was previously reported (Boyajian et al ., 1993).…”

“…There is now cumulative neuroimaging evidence that acute ischemic infarction often underlies global neurologic deficits after cardiac surgery (Boyajian et al ., 1993; Wityk et al ., 2001). This emerging concept that global and focal deficits are poles of a continuum of possible stroke manifestations after cardiac surgery has not yet been integrated into study designs for identifying stroke risk factors (Roach et al ., 1996; Wolman et al ., 1999).…”

“…After consolidating global with focal event rates, we test four putative stroke risk factors [patient age, carotid stenosis, cardiopulmonary bypass (CPB) time, any open chamber procedure] and one dummy variable (gender) for their performance as independent predictors of overall clinical neurologic deficits. For validation purposes, this inquiry is conducted in a cohort of CPB patients for which we previously reported the detailed cerebrovascular topography and pathophysiology of neuroinjury in the symptomatic patients (Boyajian et al ., 1993).…”

Cardiac surgery in the young infant: An in vivo model for the study of hypoxic-ischemic brain injury?

“…injury at a cerebral level. The most common acute presentations of cerebral injury include seizures [Ehyai et al, 1984;Newburger et al, 1993], movement disorders [Robinson et al, 1988;Wong et al, 1992;Huntley et al, 1993;Curless et al, 1994], and stroke [Terplan 1973[Terplan , 1976Mathews et al, 1986;Moody et al, 1990;Hutto et al, 1991;Boyajian et al, 1993;du Plessis et al, 1995a;Rosenthal et al, 1995]. Chronic sequelae include motor, cognitive, and behavioral impairment [Stevenson et al, 1974;Wright et al, 1979;Wells et al, 1983;du Plessis et al, 1994a;Bellinger et al, 1995].…”

“…In addition to these manifestations of presumed global HI/R injury, infant cardiac surgery may also predispose to focal cerebral vasocclusive injury or stroke [Terplan 1973[Terplan , 1976Mathews et al, 1986;Moody et al, 1990;Hutto et al, 1991;Boyajian et al, 1993;du Plessis et al, 1995a;Rosenthal et al, 1995]. Intraoperative strokes may result in longterm motor, language, and epileptic sequelae.…”