Abnormalities in the Brain Before Elective Cardiac Surgery Detected by Diffusion-Weighted Magnetic Resonance Imaging

Evaluation of the risk factors for neurological and neurocognitive impairment after selective cerebral perfusion in thoracic aortic surgery

PURPOSE

Neurologic complications are seen often after the surgery of the thoracic aorta that uses selective antegrade cerebral perfusion. The objective of this study was to evaluate the impact of atherosclerotic risk factors on neurologic complications in patients who underwent surgery to the thoracic aorta using SCP.

METHODS

Data were collected retrospectively on 94 patients who underwent elective ascending aorta/aortic arch replacement. Concomitant procedures were performed as needed. All patients had magnetic resonance imaging (MRI), angiography (MRA) and carotid ultrasound before surgery. Individual cognitive status was measured using four neuropsychological tests before surgery and 7 days after extubation. We compared perioperative factors for risk factors associated with postoperative stroke and postoperative cognitive decline (POCD).

RESULTS

11 patients had strokes after surgery. Operation and extracorporeal circulation times were significantly longer in patients with stroke than those without stroke. Coronary artery disease and SCP time > 150 min were independently associated with postoperative stroke. Of the 83 patients without postoperative stroke, 20 suffered POCD. POCD patients had a significantly higher rate of heterogeneous carotid plaque, and operation time was significant longer in patients with POCD than those without POCD. Independent predictors of POCD were concomitant CABG, heterogeneous carotid plaque, history of cerebrovascular disease and operation time > 450 min.

CONCLUSIONS

We found that prolonged SCP time and coronary artery disease increased the risk of postoperative stroke. Heterogeneous carotid plaque, history of cerebrovascular disease, concomitant CABG and prolonged operation time were further significant predictors of POCD.

MRI Markers of Neurodegenerative and Neurovascular Changes in Relation to Postoperative Delirium and Postoperative Cognitive Decline

Postoperative delirium (POD) and postoperative cognitive decline (POCD) are common in elderly patients. The aim of the present review was to explore the association of neurodegenerative and neurovascular changes with the occurrence of POD and POCD. Fifteen MRI studies were identified by combining multiple search terms for POD, POCD, and brain imaging. These studies described a total of 1,422 patients and were all observational in design. Neurodegenerative changes (global and regional brain volumes) did not show a consistent association with the occurrence of POD (four studies) or POCD (two studies). In contrast, neurovascular changes (white matter hyperintensities and cerebral infarcts) were more consistently associated with the occurrence of POD (seven studies) and POCD (five studies). In conclusion, neurovascular changes appear to be consistently associated with the occurrence of POD and POCD, and may identify patients at increased risk of these conditions. Larger prospective studies are needed to study the consistency of these findings and to unravel the underlying pathophysiological mechanisms.

Neurologic complications of cardiac and vascular surgery

This chapter will provide an overview of the major neurologic complications of common cardiac and vascular surgeries, such as coronary artery bypass grafting and carotid endarterectomy. Neurologic complications after cardiac and vascular surgeries can cause significant morbidity and mortality, which can negate the beneficial effects of the intervention. Some of the complications to be discussed include ischemic and hemorrhagic stroke, seizures, delirium, cognitive dysfunction, cerebral hyperperfusion syndrome, cranial nerve injuries, and peripheral neuropathies. The severity of these complications can range from mild to lethal. The etiology of complications can include a variety of mechanisms, which can differ based on the type of cardiac or vascular surgery that is performed. Our knowledge about neuropathology, prevention, and management of surgical complications is growing and will be discussed in this chapter. It is imperative for clinicians to be familiar with these complications in order to narrow the differential diagnosis, start early management, anticipate the natural history, and improve outcomes.

[Correction of postoperative cognitive dysfunction in cardiosurgery using computer-based stimulation programs]

AIM

To evaluate the efficacy of computer-based stimulation programs in the correction of postoperative cognitive dysfunction in patients with ischemic heart disease in remote period after coronary artery bypass surgery.

MATERIAL AND METHODS

The study involved 74 patients. All patients underwent a drug therapy and the rehabilitation course using computer-based stimulation programs (1 time per day for 20 minutes during10 days). Coronary artery bypass surgery was performed for all patients. Patients were examined before operation, after 6 and 12 months.

RESULTS

The significant improvement of higher cortical functions assessed with the FAB scale, the Schulte test, associated thinking test, ten-word retrieval test at the first attempt, the Clock drawing test) was revealed in the group using computer-based stimulation programs in comparison with the control group.

CONCLUSION

It is found that rehabilitation course using computer-based stimulation programs in patients with ischemic heart disease after coronary artery bypass surgery is the effective method of cognitive function correction.

The effectiveness of the correction of cognitive impairment using computer-based stimulation programs for patients with coronary heart disease after coronary bypass surgery

We evaluated effectiveness of using copyrighted computer-based stimulation programs in the correction of cognitive function in patients with coronary heart disease after coronary bypass surgery.A total of 74 patients were examined, all the patients underwent a course of drug therapy, 37 patients underwent a course of rehabilitation in addition to medical therapy using computer-based stimulation programs (1 time per day for 20 min within 10 days). A course of rehabilitation using computer-based stimulation programs in patients with coronary heart disease after coronary bypass surgery was proved to be an effective way of correcting cognitive function.

Neurologic outcomes of preoperative acute silent cerebral infarction in patients with cardiac surgery

Background

Acute cerebral infarction is a major risk factor for postoperative neurologic complications in cardiac surgery. However, the outcomes associated with acute silent cerebral infarction (ASCI) have not been not well established. Few studies have reported the postoperative outcomes of these patients in light of preoperative Diffusion-weighted magnetic resonance imaging (DWI). We studied the postoperative neurologic outcomes of patients with preoperative ASCI detected by DWI.

Methods

We retrospectively studied 32 patients with preoperative ASCI detected by DWI. None of the patients had preoperative neurologic symptoms. The mean age at operation was 68.8±9.5 years. Five patients had previous histories of stroke. Four patients had been diagnosed with infective endocarditis. Single cerebral infarct lesions were detected in 16 patients, double lesions in 13, and multiple lesions (>5) in three. The median size of the infarct lesions was 4 mm (range, 2 to 25 mm). The operations of three of the 32 patients were delayed pending follow-up DWI studies.

Results

There were two in-hospital mortalities. Neurologic complications also occurred in two patients. One patient developed extensive cerebral infarction unrelated to preoperative infarct lesions. One patient showed sustained delirium over one week but recovered completely without any neurologic deficits. In two patients, postoperative DWI confirmed that no significant changes had occurred in the lesions.

Conclusion

Patients with preoperative ASCI showed excellent postoperative neurologic outcomes. Preoperative ASCI was not a risk factor for postoperative neurologic deterioration.

Cognitive impairment before and six months after cardiac surgery increase mortality risk at median 11 year follow-up: a cohort study

BACKGROUND

The additive effects of cognitive impairment and depression on mortality risk after cardiac surgery are unknown.

METHODS

Patients were assessed on a battery of six neurocognitive measures before cardiac surgery (N = 521) and at six month follow up (N = 377/521, 72.4%). Cognitive impairment classification was based on cognitive test scores 1 SD below age and sex matched normative data, and classified according to amnestic, non-amnestic and mixed cognitive impairment subtypes. Survival analyses entered cognitive impairment subtypes and depression interactions terms adjusted for 12 common risk factors.

RESULTS

There were 5407 person years for analysis (median 11.1 year survival, interquartile range of 7.9 to 13.1) and 176 deaths (33.8%) by the census date. Before cardiac surgery, patients with a mixed-cognitive impairment (adjusted hazard ratio (HR) = 2.53; 95% confidence interval (CI), 1.57-4.06, p<.001) and non-amnestic cognitive impairment (adjusted HR = 1.51; 95%, 1.00-2.32, p = .05) were at greater mortality risk. Six month analyses corroborated that the mixed-cognitive impairment group were at higher mortality risk (adjusted HR = 2.35; 95% CI, 1.30-4.25, p = .005). When change in neurocognitive functioning over time was analyzed, a higher mortality risk was evident only amongst patients with cognitive impairment evident at baseline and six months (adjusted HR = 1.83; 95% CI, 1.08-3.10, p = .03). No cognition by depression interaction term was significant.

CONCLUSIONS

These data suggest that a mixed cognitive impairment subtype, and continuing cognitive impairment before and six months after cardiac surgery, is associated with long term mortality, independent of depression and common risk factors.

Impact of preexisting cerebral ischemia detected by magnetic resonance imaging and angiography on late outcome after coronary artery bypass surgery

BACKGROUND

The aim of this study was to assess the impact of preexisting ischemia detected by brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) on long-term survival, and cardiac and neurologic events after coronary artery bypass grafting (CABG).

METHODS

Of 923 patients who underwent CABG between 1994 and 2007, 887 patients (96.1%) were followed up. Preoperative brain MRI and MRA were performed in 619 patients. Ischemia was detected by brain MRI and MRA in 158 patients (group A), but not in 461 patients (group B). Preoperative characteristics, follow-up survival, and cardiac and neurological events were investigated.

RESULTS

The average follow-up period was 6.0 ± 4.3 years. Univariate analysis showed that patients in group A (68.5 ± 6.5 years) were older than those in group B (64.5 ± 8.6 years) (p = 0.0001). Preoperative left ventricular ejection fraction was less in group A (0.516 ± 0.175) than in group B (0.556 ± 0.165) (p = 0.02). The prevalence of peripheral vascular disease was higher in group A (14 patients: 8.9%) than in group B (11 patients: 2.4%) (p = 0.001). The rate of on-pump CABG was lower in group A (115 patients; 72.8%) than in group B (383 patients; 83.1%) (p = 0.007). Survival rate was significantly lower (p = 0.062), and freedom from major adverse cardiac event or stroke were significantly lower in group A (p = 0.0002, and p = 0.0001, respectively; log-rank test). However, the Cox proportional hazard model showed that preoperative brain ischemia detected by brain MRI and MRA affected only freedom from neurologic events (p = 0.02; hazard ratio 2.52; 95% confidence interval 1.13 to 5.62), but not survival (p = 0.67) or major adverse cardiac event (p = 0.09).

CONCLUSIONS

Preexisting ischemic findings on brain MRI and MRA in patients who underwent CABG were related only to long-term freedom from stroke, but were not related to survival or major adverse cardiac event.

Impaired cognition preceding cardiac surgery is related to cerebral ischemic lesions

PURPOSE

Cognitive dysfunction is more frequent after cardiac surgery. However, the preoperative cognitive state is seldom assessed when the effects of cardiac surgery on cognition are investigated. Postoperative cognitive dysfunction may be associated with the preoperative cognitive state and the existence of cerebral ischemic lesions in patients who undergo cardiac surgery.

METHODS

Data were collected prospectively on 362 consecutive patients scheduled to undergo elective cardiac surgery. The brains of all patients were imaged by magnetic resonance imaging (MRI) to assess prior cerebral infarctions, carotid artery stenosis and intracranial arterial stenosis, and diffusion-weighted imaging (DWI) was used to assess acute cerebral ischemia. Patients were classified with impaired cognitive function prior to surgery if their score on the Hasegawa dementia rating scale was <24. Postoperative cognitive dysfunction from baseline was determined using four neuropsychological tests.

RESULTS

Prior to surgery 40 patients (11%) were assessed with impaired cognition. Relative to the other patients, these patients were older and less well educated, and they had significantly higher rates of peripheral vascular disease, white matter lesions, cerebral infarction on MRI, carotid artery stenosis and postoperative cognitive dysfunction. Of these 40 cognitively impaired patients, seven (18%) had cerebral ischemia, based on DWI images before surgery; in comparison, nine of the 322 patients (3%) without preoperative cognitive impairment were found to have abnormalities on the DWI images (P < 0.001). An analysis by stepwise logistic regression demonstrated that the significant risks for preoperative cognitive impairment were advanced age, lower attained level of education, peripheral artery disease, prior cerebral infarctions, and abnormalities on DWI images.

CONCLUSIONS

These findings suggest that preoperative cognitive impairment associated with cerebral ischemic lesions and an increased risk of postoperative cognitive dysfunction existed in our patient cohort undergoing cardiac surgery.