Tomoko Baba

Magnetic resonance imaging findings and postoperative neurologic dysfunction in elderly patients undergoing coronary artery bypass grafting

BACKGROUND Small cerebral infarctions are common in elderly patients, but the association between the magnetic resonance imaging finding and neurologic dysfunction after coronary artery bypass grafting has not been evaluated. METHODS We determined, prospectively, whether varying degrees of abnormal findings on magnetic resonance images of the brain increased the incidence of preoperative cognitive decline, postoperative neuropsychological dysfunction, and stroke in 421 elderly patients (> or = 60 years) undergoing coronary artery bypass grafting. RESULTS Control patients (almost normal or leukoaraiosis, n = 212) had rates of postoperative neuropsychological dysfunction (7%) and stroke (1.4%); the small infarctions group (some small infarctions, n = 126) had rates of 13% and 5.6%, respectively; whereas patients with multiple infarctions (multiple small infarctions or broad infarctions, n = 83) had rates of 20% and 8.4%, respectively (p = 0.004, p = 0.013). In the group with multiple infarctions, 49 patients (59%) were asymptomatic and 21 patients (25%) had cognitive decline. Stepwise logistic regression analysis demonstrated that the significant predictors of multiple small infarctions or large infarctions were history of cerebrovascular disease, renal insufficiency, cognitive decline, and cerebral arteriosclerosis. CONCLUSIONS Multiple infarctions significantly increase the risk of neurologic dysfunction after coronary artery bypass grafting. Routine screening for preoperative cognitive decline should be performed to detect underlying ischemic cerebral disease in elderly patients.

Aortic atherosclerosis and postoperative neurological dysfunction in elderly coronary surgical patients.

BACKGROUND Arteriosclerosis of the ascending aorta is an important risk factor for cerebral embolism. However, the association between arteriosclerosis of the ascending aorta and neurologic dysfunction after coronary artery surgery has not been evaluated prospectively. METHODS We examined whether varying degrees of arteriosclerosis in the ascending aorta, assessed by epiaortic ultrasonography, increased the incidence of neuropsychologic dysfunction and stroke in 463 elderly patients (> or = 60 years old) after coronary artery surgery. RESULTS Patients with severe arteriosclerosis (n = 76) had higher rates of postoperative neuropsychologic dysfunction (26%) and intraoperative stroke (10.5%); the moderately atherosclerotic patients (n = 57) had rates of 7% and 1.8%, respectively; whereas control patients (almost normal or mild arteriosclerosis, n = 330) had rates of 8% and 1.2%, respectively (all p < 0.001). Univariate analysis indicated that multiple small infarctions or broad infarctions, cerebral arterial stenosis, circulatory arrest, maximal thickness of intima around the site of aortic manipulation, and deformities due to clamp or cannulation were associated significantly with intraoperative strokes in patients with severe arteriosclerosis. CONCLUSIONS Severe arteriosclerosis of the ascending aorta significantly increased the risk of postoperative neuropsychologic dysfunction and stroke after coronary artery bypass grafting. If a thick plaque is noted near the manipulation site, a nontouch method of the ascending aorta should be applied to reduce the incidence of neurologic dysfunction.

Craniocervical and aortic atherosclerosis as neurologic risk factors in coronary surgery.

BACKGROUND Advanced age is associated with increased systemic atherosclerosis and is a consistent neurologic risk factor after coronary artery bypass grafting (CABG). METHODS We studied prospectively whether varying degrees of a total atherosclerotic score derived from the brain, carotid arteries, and ascending aorta predicted postoperative neuropsychologic (NP) dysfunction and stroke in 177 elderly patients (> or = 60 years) undergoing CABG. RESULTS Group L (low total atherosclerotic score) had rates of NP dysfunction of 25% and 4%, group I (intermediate) had rates of 33% and 22%, and group H (high) had rates of 79% and 43% on postoperative days 1 and 7, respectively (p < 0.001). The incidence of stroke was higher in group H (14.3%) than in groups I and L (7.8% and 0.9%; p = 0.013). Stepwise logistic regression analysis demonstrated the significant predictors of NP dysfunction on postoperative day 7 to be total atherosclerotic score, peripheral vascular disease, and diabetes mellitus, and those of stroke to be total atherosclerotic score, peripheral vascular disease, and hyperlipidemia. CONCLUSIONS Perioperative evaluation of craniocervical and aortic atherosclerosis is useful to identify a high-risk patient at postoperative NP dysfunction and stroke after CABG.

Cerebral ischemic disorders and cerebral oxygen balance during cardiopulmonary bypass surgery : Preoperative evaluation using magnetic resonance imaging and angiography

We compared the preoperative prevalence of small cerebral infarctions and carotid stenosis to jugular venous oxygen saturation (SjVO2) during coronary artery bypass grafting (CABG).SjVO2 served as an indicator of whether cerebral oxygen supply meets demand in patients on cardiopulmonary bypass (CPB). The study population consisted of 121 patients who were either older than 65 yr or had a history of cerebrovascular disease. The patients underwent preoperative cerebral magnetic resonance imaging (MRI) and cervical magnetic resonance angiography (MRA) to detect small cerebral infarctions and carotid artery stenosis. Patients with atherosclerosis of the ascending aorta were identified by intraoperative epiaortic ultrasonography. Liberation of emboli from the aorta in these patients was prevented by modification of the standard operation. From preoperative MRI and MRA, 65 patients (54%) had small cerebral infarctions in the white matter or basal ganglia and nine patients (7%) demonstrated moderate or severe stenosis in the carotid arteries. Thirteen patients (11%) had moderate or severe atheromatous disease of the ascending aorta. The severity of aortic atherosclerosis was significantly correlated with the grade of carotid stenosis (P < 0.05). In patients with small infarctions, SjVO2 was significantly lower than in patients without infarctions (controls) at initiation of CPB, 30 min after aortic cross-clamping, and during the rewarming period of CPB (P < 0.05). Thus, small cerebral infarctions were not uncommon in elderly patients undergoing CABG. Patients with small cerebral infarctions may be at risk for an imbalance in cerebral oxygen supply and demand during the rewarming period because they are unable to deliver the necessary compensatory blood flow. (Anesth Analg 1997;84:5-11)

Pre-existing cerebral infarcts as a risk factor for delirium after coronary artery bypass graft surgery

OBJECTIVES Delirium is a common and critical clinical syndrome in older patients. We examined whether abnormalities in the brain that could be assessed by magnetic resonance imaging predisposed patients to develop delirium after coronary artery bypass graft surgery. We also analysed the association between delirium and cognitive dysfunction after coronary artery bypass graft surgery. METHODS Data were collected prospectively on 153 patients aged 60 years or older who consecutively underwent elective isolated coronary artery bypass graft surgery. All patients were assessed for prior cerebral infarctions and craniocervical artery stenosis by magnetic resonance imaging (MRI) and angiography of their brains. Atherosclerosis of the ascending aorta was examined by epiaortic ultrasound at the time of surgery. Individual cognitive status was measured using four tests in all the patients before surgery and on the seventh postoperative day. A single psychiatrist diagnosed delirium using the Diagnostic and Statistical Manual of Mental Disorders 4th edition IV criteria. RESULTS Postoperative delirium occurred in 16 patients (10.5%). Compared with patients who did not develop postoperative delirium, delirious patients had significantly higher rates of peripheral artery disease, preoperative decline in global cognitive function and pre-existing multiple cerebral infarctions on MRI. In addition, 9 (56%) of the delirious patients suffered postoperative cognitive dysfunction. Stepwise logistic regression analysis found significant independent predictors of postoperative delirium to be preoperative cerebral infarcts on MRI (odds ratio [OR], 2.26; 95% confidence interval [CI] 1.10-4.78), preoperative decline in global cognitive function (OR 4.54; 95% CI 1.21-16.51) and atherosclerosis of the ascending aorta (OR 2.44; 95% CI 1.03-5.62). CONCLUSIONS Our findings suggested that postoperative delirium was associated with pre-existing multiple cerebral infarctions on MRI, preoperative decline in global cognitive function and ascending aortic atherosclerosis in elderly patients undergoing coronary artery bypass graft surgery and increased risk of postoperative cognitive dysfunction.

Radial artery diameter decreases with increased femoral to radial arterial pressure gradient during cardiopulmonary bypass.

A clinically significant femoral to radial artery pressure gradient sometimes develops during cardiopulmonary bypass (CPB), but the mechanism responsible is not clear.We investigated when the pressure gradient developed and what mechanism could be responsible by comparing mean femoral to mean radial artery pressure and radial artery diameter in 75 male patients undergoing coronary artery bypass grafting. A pressure gradient >or=to5 mm Hg (High-P) occurred in 38 patients, and the remaining 37 patients had pressure gradients <5 mm Hg (Low-P) at sternal closure. In High-P group, the pressure gradient was significantly greater (4.8 +/- 3.1 vs 1.0 +/- 3.1 mm Hg; P < 0.001) than in Low-P group, and the ratio of radial artery diameter to the diameter after induction of anesthesia was significantly decreased (0.79 +/- 0.12 vs 0.87 +/- 0.14; P = 0.006) at 5 min after aortic clamping. The pressure gradient and the arterial diameter changes persisted until sternal closure. There was a negative linear correlation between the pressure gradient (Delta P) and the radial artery diameter ratio (D) at sternal closure (D = -15.0 Delta P + 16.6, r = 0.39, P < 0.001). In a subgroup of 11 High-P patients, palm temperature was significantly lower (P < 0.05) than that of 11 Low-P patients during and after CPB. We conclude that the femoral to radial artery pressure gradient develops by 5 min after aortic clamping during CPB and persists until sternal closure, and that radial artery constriction could be responsible for the pressure gradient. Implications: A femoral to radial pressure gradient has been observed after cardiopulmonary bypass. Arterial vasodilation and vasoconstriction have been considered as causes for this gradient. We measured radial artery diameter using pulsed Doppler ultrasound and examined radial artery vasodilation versus vasoconstriction as possible mechanisms for the pressure gradient. (Anesth Analg 1997;85:252-8)

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

BACKGROUND Diffusion-weighted magnetic resonance imaging (DWI) has found ischemic lesions in the brain after cardiac surgery. However, preoperative cerebral injury has not been studied closely. In this study, we used DWI to assess the prevalence of abnormalities in patients scheduled for cardiac surgery. METHODS We used conventional magnetic resonance imaging and DWI to study 247 consecutive patients scheduled for elective cardiac surgery. Clinical characteristics, neuropsychological test performance, and radiographic data were collected and compared with a group of patients who had normal findings on DWI. RESULTS Eleven of the 247 patients (4.5%) had cerebral ischemic lesions on DWI before surgery. Compared with patients who had normal findings on DWI, patients who had abnormalities had significantly higher rates of history of cerebrovascular disease (64% versus 12%), cardiac catheterization within 14 days before DWI (91% versus 54%), preoperative cerebral infarctions (45% versus 5%), carotid artery stenosis (36% versus 5%), and preoperative cognitive impairment (55% versus 9%). Of the 11 patients with DWI abnormalities, 5 had delayed elective surgery and follow-up image studies; of these 5, 4 showed no relevant ischemic lesion on preoperative follow-up imaging. Among the other 6 patients, 1 had an infarction due to expansion of the same lesion that was detected on the preoperative DWI. There was no significant difference with regard to the incidence of postoperative stroke and cognitive dysfunction. CONCLUSIONS In all, 4.5% of cardiac surgery patients had existing cerebral ischemic lesions on DWI without obvious neurologic defects. Further studies are required to determine whether the lesions are associated with postoperative cognitive dysfunction or stroke.

Gender Differences in Stroke Risk Among the Elderly After Coronary Artery Surgery

BACKGROUND: Previous studies have shown that women are at higher risk than men for stroke after coronary artery bypass graft (CABG) surgery, but gender differences in systemic atherosclerosis have not been studied adequately. We investigated gender differences in the incidence of craniocervical and ascending aortic atherosclerosis and other risk factors for stroke in elderly patients (age ≥60 yr) undergoing CABG surgery. METHODS: Data were prospectively collected on 720 patients (31.8% women) undergoing CABG surgery. All patients underwent preoperative brain magnetic resonance imaging and angiography to assess for prior cerebral infarctions, carotid artery stenosis, and intracranial arterial stenosis. Epiaortic ultrasound was performed at the time of surgery to assess for atherosclerosis of the ascending aorta. Cognitive status was measured using the Hasegawa-dementia score in all patients before surgery and on the seventh postoperative day. RESULTS: Women were older and had more hypertension and intracranial arterial stenosis than did men. Men had significantly higher rates of hyperlipidemia, peripheral vascular disease, abdominal aortic aneurysm, smoking history, severe carotid artery stenosis, and severe aortic atherosclerosis than did women. Although there were no differences in prior cerebral infarction or preoperative cognitive impairment, the rate of perioperative stroke was marginally higher in men than in women (3.9% vs 1.3%, P = 0.066). Univariate predictors of perioperative stroke were prior cerebral infarctions, ascending aortic atherosclerosis, preexisting cognitive impairment, and peripheral vascular disease. Stepwise logistic regression analysis demonstrated that significant independent predictors of perioperative stroke were prior cerebral infarctions and aortic atherosclerosis. CONCLUSIONS: These data suggest that men are more likely than women to have risk factors for stroke, including severe carotid artery stenosis, severe aortic atherosclerosis, and peripheral vascular disease. The rates of prior cerebral infarction and preoperative cognitive impairment were similar between genders.

Early neuropsychological dysfunction in elderly high-risk patients after on-pump and off-pump coronary bypass surgery

PurposeAdvanced age is associated with systemic atherosclerosis and is a risk factor for neurological dysfunction after coronary artery bypass grafting (CABG). However, few studies have investigated early neurological dysfunction after off-pump CABG in elderly patients.MethodsData were collected prospectively on 218 patients (≥60 years) who underwent elective off-pump (n = 89) or on-pump CABG (n = 129). Four cognitive tests were performed preoperatively and 1 week postoperatively. Neuropsychological (NP) dysfunction was defined as a decrease in an individuals performance in more than two tests of at least 20% from baseline. We compared the incidence of NP dysfunction, stroke, graft patency grading, and systemic atherosclerosis between patients who underwent off-pump and on-pump CABG.ResultsOff-pump patients were more likely to have a history of cerebrovascular disease, peripheral vascular disease, smoking, multiple cerebral infarctions, and severe aortic atherosclerosis. None of the off-pump and three on-pump patients suffered intraoperative strokes (P = 0.27). The incidence of NP dysfunction was 11.2% in the off-pump group and 22.5% in the on-pump group, (P = 0.02). Multivariate analysis revealed that NP dysfunction was associated with cardiopulmonary bypass (CPB) and multiple cerebral infarctions. The off-pump group had fewer vessels grafted (2.4 vs 3.4; P < 0.01), and a higher rate of stenosis (>50%) and occlusion of the grafted vessels (13.0% vs 7.4%; P = 0.01) than the on-pump group.ConclusionOff-pump CABG reduced postoperative NP dysfunction in elderly patients with severe systemic atherosclerosis compared to on-pump CABG.

Analysis of factors related to jugular venous oxygen saturation during cardiopulmonary bypass

OBJECTIVE To investigate preoperative clinical conditions and/or intraoperative physiologic variables related to jugular venous oxygen saturation (SjO2) during cardiopulmonary bypass (CPB). DESIGN Prospective study. SETTING General hospital, single institution. PARTICIPANTS One hundred forty patients (52 women, 88 men) who underwent coronary artery bypass grafting. MEASUREMENTS AND MAIN RESULTS The authors measured SjO2 at five times during surgery. Multiple stepwise regression analysis showed a significant correlation of SjO2 with (1) arterial carbon dioxide partial pressure (PaCO2) before CPB (standard regression coefficient [(SC)] = 0.435), (2) cerebral perfusion pressure (CPP) during initiation of CPB (SC = 0.259), (3) PaCO2, tympanic temperature (TT), bubble oxygenator, and cerebral small infarctions (CSIs) during hypothermic CPB (SC = 0.507, -0.237, -0.192, and -0.189, respectively), (4) CPP, PaCO2, CSIs, and bubble oxygenator during rewarming (SC = 0.476, 0.294, -0.220, and -0.189, respectively), and (5) PaCO2 after CPB (SC = 0.480; p < 0.01). Correlation coefficients between SjO2 and CPP during rewarming were 0.40 (0.46 without CSI and 0.37 with CSI; p < 0.01). These results indicate that the relationship between CPP and SjO2 was significant in patients with CPP less than 40 mmHg during rewarming. CONCLUSION During rewarming, when cerebral perfusion and oxygen demand change abruptly, but not during stable hypothermic CPB, CPP was a significant factor related to sjO2.