Atherosclerosis of the ascending aorta. Prevalence and role as an independent predictor of cerebrovascular events in cardiac patients

Thoracic aorta calcification detected by electron beam tomography predicts all-cause mortality

BACKGROUND

The presence of coronary artery calcium (CAC) is an independent marker of increased risk of cardiovascular disease (CVD) events and mortality. However, the predictive value of thoracic aorta calcification (TAC), which can be additionally identified without further scanning during assessment of CAC, is unknown.

METHODS

We followed a cohort of 8401 asymptomatic individuals (mean age: 53+/-10 years, 69% men) undergoing cardiac risk factor evaluation and TAC and CAC testing with electron beam computed tomography. Multivariable Cox proportional hazards models were developed to predict all-cause mortality based on the presence of TAC.

RESULTS

During a median follow-up period of 5 years, 124 (1.5%) deaths were observed. Overall survival was 96.9% and 98.9% for those with and without detectable TAC, respectively (p<0.0001). Compared to those with no TAC, the hazard ratio for mortality in the presence of TAC was 3.25 (95% CI: 2.28-4.65, p<0.0001) in unadjusted analysis. After adjusting for age, gender, hypertension, dyslipidemia, diabetes mellitus, smoking and family history of premature coronary artery disease, and presence of CAC the relationship remained robust (HR 1.61, 95% CI: 1.10-2.27, p=0.015). Likelihood ratio chi(2) statistics demonstrated that the addition of TAC contributed significantly in predicting mortality to traditional risk factors alone (chi(2)=13.62, p=0.002) as well as risk factors+CAC (chi(2)=5.84, p=0.02) models.

CONCLUSION

In conclusion, the presence of TAC was associated with all-cause mortality in our study; this relationship was independent of conventional CVD risk factors as well as the presence of CAC.

Effects of poly-2-methoxyethylacrylate (PMEA)-coating on CPB circuits

OBJECTIVES

In this study, the immuno- and neuroprotective effect of a novel cardiopulmonary bypass coating was investigated.

DESIGN

Thirty nine patients scheduled for elective coronary artery bypass grafting were randomly assigned to either PMEA-coated (n = 19) or non-coated CPB circuits (n = 20). Pericardial suction blood was separated and retransfused only if needed at the end of operation. Neurocognitive functions were examined preoperatively and 7-10 days postoperatively using a standard neuropsychological test battery. Assuming an inflammatory etiology, the most cogent inflammatory markers were perioperatively analyzed.

RESULTS

Postoperatively, patients of the PMEA-coated group performed better in Go/NoGo and Mini-Mental-test than patients of the non-coated group (p < 0.04). Other neurocognitive testing did not reveal significant differences between the groups. Although most inflammatory parameters showed a significant intraindividual increase during or shortly after CPB, there was no difference in inflammatory alteration between the groups.

CONCLUSIONS

PMEA-coating of cardiopulmonary bypass surfaces revealed some minor benefits in preservation of neurocognitive functions after surgery. The immediate inflammatory response remained mostly unaffected. Suction blood separation may additionally contribute to proper postoperative outcome.

Aortic arch atheroma

Severe atheroma of the aortic arch has now been established as an important risk factor and mechanism for stroke and peripheral embolism. The odds ratio for stroke or peripheral embolism in patients with severe arch atheroma is greater than four, and for mobile atheroma it is greater than 12. The prevalence of severe arch atheroma among patients presenting with acute ischaemic stroke, at over 20%, is in the same order as that of atrial fibrillation and carotid atherosclerosis. In patients with ischaemic stroke for which no cause has been identified, it is reasonable to determine as to whether they have severe arch atheroma by performing a transoesophageal echocardiogram. Recurrent stroke is common in patients with aortic arch atheroma that are thicker than 4 mm or with mobile components, particularly in the elderly, cigarette smokers, and those with hypertension or diabetes. Patients found to have severe atheroma are at high risk of recurrent events (14.2% per year) and may, therefore, need an aggressive secondary prevention strategy. Currently, there is uncertainty as to what this should be, but either combination antiplatelet therapy (aspirin plus clopidogrel) or anticoagulation with warfarin (target INR 2.0-3.0) are commonly used. Which of these is most effective will be evident after the completion of the aortic arch related cerebral hazard trial.

Epiaortic scanning modifies planned intraoperative surgical management but not cerebral embolic load during coronary artery bypass surgery

BACKGROUND

Patients with aortic atheroma are at increased risk for neurological injury after coronary artery bypass graft (CABG) surgery. We sought to determine the role of epiaortic ultrasound scanning for reducing cerebral embolic load, and whether its use leads to changes of planned intraoperative surgical management in patients undergoing CABG surgery.

METHODS

Patients >70-yr-of-age scheduled for CABG surgery were prospectively randomized to either an epiaortic scanning (EAS) group (aortic manipulation guided by epiaortic ultrasound) or a control group (manual aortic palpation without EAS). All patients received a comprehensive transesophageal echocardiographic examination. Transcranial Doppler (TCD) was used to monitor the middle cerebral arteries for emboli continuously from 2 min before aortic cannulation to 2 min after aortic decannulation. Neurological assessment was performed with the National Institute of Health stroke scale before surgery and at hospital discharge. The NEECHAM confusion scale was used for assessment and monitoring of patient global cognitive function on each day after surgery until hospital discharge.

RESULTS

Intraoperative surgical management was changed in 16 of 55 (29%) patients in the EAS group and in 7 of 58 (12%) patients in the control group (P = 0.025). These changes included adjustments of the ascending aorta cannulation site for cardiopulmonary bypass (CPB), the avoidance of aortic cross-clamping by using ventricular fibrillatory arrest during surgery, or by conversion to off-pump surgery. During surgery, 7 of 58 (12%) patients in the control group crossed over to the EAS group based on the results of manual aortic palpation. The median [range] TCD detected cerebral embolic count did not differ between the EAS and control groups during aortic manipulations (EAS, 11.5 [1-516] vs control, 22.0 [1-160], P = 0.91) or during CPB (EAS, 42.0 [4-516] vs control, 63.0 [5-758], P = 0.46). The NEECHAM confusion scores and National Institute of Health stroke scale scores were similar between the two groups.

CONCLUSIONS

These results show that the use of EAS led to modifications in intraoperative surgical management in almost one-third of patients undergoing CABG surgery. The use of EAS did not lead to a reduced number of TCD-detected cerebral emboli before or during CPB.

Differences in atherosclerotic profiles between patients with thoracic and abdominal aortic aneurysms

Differences in atherosclerotic profiles between patients with thoracic aortic aneurysm (TAA) and patients with abdominal aortic aneurysm (AAA) have not been studied. We retrospectively studied the clinical records of 343 consecutive patients (132 TAA and 211 AAA) who were admitted to our hospital for elective repair of aortic aneurysms between July 2001 and December 2004. Clinical variables were compared between patients with TAA and those with AAA by using a univariate analysis, and those achieving statistical significance were subsequently assessed in a multivariate analysis. The incidence of coronary artery disease (CAD) (53% vs 23%, p <0.0001), 3-vessel coronary disease (41% vs 10%, p <0.0001), male gender (86% vs 74%, p <0.01), smoker (88% vs 76%, p <0.01), chronic obstructive pulmonary disease (COPD) (30% vs 15%, p <0.01), and diabetes mellitus (39% vs 23%, p <0.01) were significantly higher in patients with AAA than in those with TAA. In contrast, the incidence of hypertension (91% vs 81%, p <0.05), saccular-type aneurysm (61% vs 7%, p <0.0001), and body mass index (24.1 +/- 3.1 vs 23.2 +/- 3.5, p <0.05) were significantly higher in patients with TAA than in those with AAA. Multivariate stepwise logistic analysis revealed that CAD (odds ratio [OR] 3.65; 95% confidence interval [CI] 2.12 to 6.42; p <0.0001), COPD (OR 2.05; 95% CI 1.11 to 3.89; p <0.05), and diabetes mellitus (OR 1.85; 95% CI 1.06 to 3.27; p <0.05) were associated with AAA, and that body mass index (OR 9.39; 95% CI 2.0 to 46.8; p <0.01), hypertension (OR 3.09; 95% CI 1.48 to 6.87; p <0.01), and cerebral infarction (OR 2.83; 95% CI 1.25 to 6.50; p <0.05) were associated with TAA. In conclusion, atherosclerotic profiles are significantly different between patients with TAA and patients with AAA. This result suggests the possibility that mechanisms underlying the development of aortic aneurysms may differ between TAA and AAA, and, from the perspective of prevention, provides further stimulus for the modification of key risk factors for atherosclerosis.

Patients at high risk for ischemic stroke: identification and actions

Atherosclerosis is a disease of chronic inflammation. It is diffuse, multisystemic and affects the vascular, metabolic and immune systems. The traditional evaluation of risk is based on methods of clinical and biological assessments, and conventional imaging. The existence of symptomatic disease and the number of symptomatic sites of atherothrombosis are critical factors in predicting the recurrence of major vascular events. However, these methods are insufficient to predict near-future episodes, above all in the individual standard clinical practice. Active treatment of modifiable risk factors such as hypertension, dyslipidemia and atrial fibrillation can reduce the number of patients who develop a stroke. There is considerable evidence suggesting that a substantial proportion of the population with high blood pressure receives insufficient treatment. More active treatment of this condition is probably the most efficient single measure. Lifestyle factors such as smoking, diet, physical inactivity and obesity contribute to the relatively high incidence of stroke. There is a need to incorporate new systemic markers and new investigation techniques in the future so as to identify the individuals at risk in the population and to administer more individualized intervention therapies.

The impact of increasing age on anatomic factors affecting carotid angioplasty and stenting

PURPOSE

Current evaluations of carotid artery angioplasty and stenting (CAS) have suggested equivalency compared with carotid endarterectomy (CEA). However, the incidence of stroke and death with CAS may be higher in elderly patients. We assessed the anatomic characteristics of patients undergoing CAS and compared them based on age older or younger than 80 years. The impact of age on the incidence of postoperative complications was also determined.

METHODS

From February 2003 to August 2005, 135 CAS procedures were performed in 133 patients. Digital subtraction angiograms for each patient were evaluated by two independent observers blinded to patient identifiers. Anatomic characteristics that impact the performance of CAS were assessed as either favorable or unfavorable. These included aortic arch elongation, arch calcification, arch vessel origin stenosis, common and internal carotid artery tortuosity, and treated lesion stenosis, calcification, and length. Postoperative events were defined as myocardial infarction, stroke, and death. Fisher's exact test and chi(2) tests were used to determine statistical significance (P < .05).

RESULTS

Of the 133 patients treated, 87 (65%) were men and 46 (35%) were women; and 37 (28%) were >or=80 years of age. The cohort >or=80 years old had an increased incidence of unfavorable arch elongation (P = .008), arch calcification (P = .003), common carotid or innominate artery origin stenosis (P = .006), common carotid artery tortuosity (P = .0009), internal carotid artery tortuosity (P = .019), and treated lesion stenosis (P = .007). No significant difference was found for treated lesion calcification or length. Perioperative cerebral vascular accidents occurred in four patients (3.0%, 3 with no residual deficit, 1 with residual deficit), myocardial infarction in three (2.2%), and one patient (0.8%) died secondary to a hemorrhagic stroke. The combined stroke, myocardial infarction, and death rate for the entire population was 3.7%. The rate was significantly increased in patients aged >or=80 years old (10.8%) compared with those aged <80 years old (1%, P = .012).

CONCLUSIONS

Elderly patients, defined as those aged >80 years, have a higher incidence of anatomy that increases the technical difficulty of performing CAS. This increase in unfavorable anatomy may be associated with complications during CAS. Although the small number of perioperative events does not allow for determination of a direct relationship with specific anatomic characteristics, the presence of unfavorable anatomy does warrant serious consideration during evaluation for CAS in elderly patients.

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 > or =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.

Significance of aortic atheroma in elderly patients with ischemic stroke

OBJECTIVES

Cardioembolism accounts for 15-30% of ischemic strokes. Transesophageal echocardiography (TEE) is useful in detecting potential sources of cardiac embolism. Aortic atheromas have recently been recognized as important causes of stroke. The aim of this study was to evaluate TEE findings in elderly patients with ischemic stroke. A review of literature was done to highlight the significance of aortic atherosclerotic disease in patients with ischemic stroke.

METHODS

One hundred consecutive patients with ischemic stroke aged > or =55 years underwent TEE for evaluation of cardiac sources of embolism. Patients with significant carotid artery stenosis (stenosis of >50% in common or internal carotid arteries) were excluded.

RESULTS

The most noteworthy finding was the high prevalence of complex atheromatous plaques in the ascending aorta and/or aortic arch (25%).

CONCLUSION

The present study demonstrates that TEE is helpful to detect cardiovascular sources of embolism in elderly patients with ischemic stroke. Aortic atheroma is present in 25% of elderly patients with ischemic stroke and without significant carotid artery stenosis. Aortic atherosclerosis may be an important cause of ischemic stroke in this population.

Transthoracic Echocardiographic Diagnosis of Mobile Aortic Arch Atherothrombosis Associated with Stroke

Aortic arch atherosclerosis is associated with an increased risk of stroke or TIA. Up to now, transesophageal echocardiography has been the standard method for diagnosing protruding and/or mobile aortic arch atherosclerosis. We report a case where a mobile aortic arch atheroma was diagnosed using transthoracic echo in a patient with a recent stroke.

Early results of a comprehensive operative and perfusion strategy to attenuate the incidence of adverse neurological outcomes in on-pump coronary artery bypass grafting (CABG) patients

Adverse neurological events, both focal (Type I) and non-focal (Type II), have been appreciated in postoperative on-pump coronary artery bypass grafting (CABG) patients for many years. Advanced age is a significant risk factor for adverse neurological events following CABG surgery. With full knowledge that our elderly population of patients was at high risk for these untoward neurological events, we adopted a comprehensive operative and perfusion strategy in an attempt to attenuate the incidence of these complications. Our strategy included efforts to minimise the number of emboli generated during the operation, avoid cerebral hypoperfusion, and attenuate the systemic inflammatory response. From 15 August 2002 to 31 December 2005, we performed 355 on-pump CABG operations. The incidence of Type I focal injury was 0/355 (0%), the incidence of Type II non-focal injury was 9/355 (2.5%), and postoperative mortality was 2/355 (0.6%). These results compared favorably to the results predicted by the Society of Thoracic Surgeons' (STS) model, and may suggest efficacy.

A single-blinded case controlled study on effects of cardiopulmonary circulation on hearing during coronary artery bypass grafting

OBJECTIVES

To evaluate the effect of extra-corporeal (cardiopulmonary) bypass on hearing during coronary artery bypass grafting.

DESIGN

Prospective (single-blinded) controlled study.

SETTING

District General Hospital.

PARTICIPANTS

Fifty-two patients undergoing coronary artery bypass grafting completed this study. Comparison was made between 14 control patients undergoing off-pump coronary artery bypass grafting and 38 study patients undergoing on-pump coronary artery bypass grafting. The age range of patients was 48-81 years, with 50% between 64 and 66 years.

MAIN OUTCOME MEASURES

Pure tone audiograms were performed in all patients before and after coronary artery bypass grafting. Data were analysed for any significant difference between pre- and post-operative pure tone audiograms.

RESULTS

Mann-Whitney U-test demonstrated no difference between the area generated between mean pre- and post-operative audiograms (P = 0.754). No significant difference between off versus on pump was demonstrated for average differences at 250-500 Hz, 4 kHz, 4-8 kHz and 8 kHz. Wilcoxon matched-pairs signed-rank test demonstrated no difference between right and left ears for each individual frequency. Spearman's test to analyse the effect on vessel number or minutes on bypass pump revealed no significant difference at 4-8 kHz (P = 0.550 for number of vessels and P = 0.276 for minutes on pump.)

CONCLUSION

In this study, it was not possible to demonstrate any statistically significant deleterious effect of extra-corporeal (cardiopulmonary) bypass on hearing during coronary artery bypass grafting.

Cardiopulmonary bypass management and neurologic outcomes: an evidence-based appraisal of current practices

Neurologic complications after cardiac surgery are of growing importance for an aging surgical population. In this review, we provide a critical appraisal of the impact of current cardiopulmonary bypass (CPB) management strategies on neurologic complications. Other than the use of 20-40 microm arterial line filters and membrane oxygenators, newer modifications of the basic CPB apparatus or the use of specialized equipment or procedures (including hypothermia and "tight" glucose control) have unproven benefit on neurologic outcomes. Epiaortic ultrasound can be considered for ascending aorta manipulations to avoid atheroma, although available clinical trials assessing this maneuver are limited. Current approaches for managing flow, arterial blood pressure, and pH during CPB are supported by data from clinical investigations, but these studies included few elderly or high-risk patients and predated many other contemporary practices. Although there are promising data on the benefits of some drugs blocking excitatory amino acid signaling pathways and inflammation, there are currently no drugs that can be recommended for neuroprotection during CPB. Together, the reviewed data highlight the deficiencies of the current knowledge base that physicians are dependent on to guide patient care during CPB. Multicenter clinical trials assessing measures to reduce the frequency of neurologic complications are needed to develop evidence-based strategies to avoid increasing patient morbidity and mortality.

Off-pump coronary bypass surgery: risk of ischemic brain lesions in patients with atheromatous thoracic aorta

PURPOSE

The purpose of this study was to determine if there is an association between the proximal thoracic aortic (ascending aorta and aortic arch) atheroma and ischemic brain lesions on diffusion-weighted magnetic resonance imaging (DW-MRI) after on-pump (ONCAB) and off-pump (OPCAB) coronary artery bypass surgery.

METHODS

Patients who underwent ONCAB surgery (n = 13) and who had aortic atheroma > 2 mm were compared to a risk-adjusted prospective cohort of patients (n = 13) undergoing OPCAB surgery. Transesophageal echocardiography and epiaortic scanning were performed to assess the proximal thoracic aorta. Patients were evaluated for new ischemic brain lesions utilizing DW-MRI three to seven days after surgery. The NEECHAM confusion scale was used to evaluate patient consciousness.

RESULTS

The groups were comparable with respect to demographic data, and prevalence of preoperative risk factors. The extent and severity of aortic atheroma was similar in the two groups. The average maximum height of atheroma was 5.0 +/- 2.0 mm in the OPCAB and 4.8 +/- 1.9 in the ONCAB groups, respectively. The prevalence of new ischemic brain lesions on DW-MRI was 0% in the OPCAB group and 61% in the ONCAB group (P = 0.001). Patients in the OPCAB group were less confused during the first two postoperative days.

CONCLUSION

Patients with aortic atheroma > 2 mm may have a lower risk of new ischemic brain lesions as identified by DWMRI after OPCAB surgery. Patient stratification based upon aortic atheroma burden should be addressed in future trials designed to tailor treatment strategies to improve short- and long-term neurological outcomes in patients undergoing cardiac surgery.

Combined carotid endarterectomy and coronary artery bypass grafting in patients with asymptomatic high-grade stenoses: An analysis of 758 procedures

PURPOSE

Surgical treatment of hemodynamically significant carotid artery stenoses has been well documented, especially in the asymptomatic patient. However, in those patients presenting with hemodynamically significant asymptomatic carotid artery disease who are to undergo cardiac surgery, optimal treatment remains controversial. In this study, we analyze our experience with patients who underwent synchronous carotid endarterectomy (CEA) and coronary artery bypass graft procedures (CABG) for hemodynamically significant (>70%) asymptomatic carotid artery stenosis and coronary artery disease (CAD).

METHODS

Demographics and outcomes of all patients undergoing synchronous CEA/CABG for asymptomatic carotid stenosis between April 1980 and January 2005 were reviewed from our vascular registry and patient charts. We included patients who underwent standard patching of their carotid artery and those undergoing eversion CEA. All neurologic events within the first 30 days that persisted >24 hours were considered a stroke. For purposes of comparison, we also reviewed outcomes for patients undergoing synchronous CEA/CABG for symptomatic carotid stenosis.

RESULTS

Asymptomatic carotid artery stenosis (>70%) was the indication in 702 patients (276 women and 426 men) undergoing 758 CEAs. In the asymptomatic group, 22 patients, of which 21 succumbed to cardiac dysfunction, and one died from a hemorrhagic stroke. The overall mortality rate was 3.1%. Seven permanent nonfatal neurologic deficits occurred in this series (1 woman, 6 men). The combined stroke mortality was 4.3%. This compares to a 30-day stroke mortality of 6.1% in 132 symptomatic combined CEA/CABG patients. The difference in stroke mortality in women compared with men was not significant.

CONCLUSION

In this experience, patients presenting with hemodynamically significant (>70%) asymptomatic carotid artery stenosis can undergo synchronous CEA/CABG with low morbidity and mortality.

Aortic arch atheroma and the risk of stroke

Brain infarction of unknown cause, known as cryptogenic stroke, represents 30% to 40% of all ischemic strokes, or approximately 400,000 cases each year in western Europe. In this category of patients new potential causes, such as aortic arch atheroma in the elderly, have been investigated in the past two decades.

The degree of atherosclerosis in the descending aorta does not predict poor in-hospital outcome after surgery requiring cardiopulmonary bypass

OBJECTIVE

This study examined if the degree of atherosclerosis in the descending aorta is an independent predictor of poor in-hospital outcome for patients presenting for surgery involving cardiopulmonary bypass.

DESIGN

The degree of atherosclerosis of the descending aorta was retrospectively reviewed in patients presenting for surgical procedures involving cardiopulmonary bypass from January 1, 2000, to December 31, 2003. Preoperative risk factors and in-hospital postoperative outcome parameters were obtained.

SETTING

University teaching hospital.

PARTICIPANTS

There were 310 consecutive patients enrolled in the study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred forty-seven patients had coronary artery bypass grafting with or without valvular surgery, and 63 patients had isolated valvular surgery. The degree of atherosclerosis was rated as normal in 86 (28%), mild in 106 (34%), moderate in 69 (22%), and severe in 49 (16%) patients. Adjusting only for the degree of atherosclerosis, the total intensive care unit (ICU) time and the number of deaths were significantly higher in those patients with severe disease. Multivariable models adjusting for patients' risk factors showed a significant influence of atherosclerosis on total ICU time but not on other outcomes. The strongest predictor of poor outcome was a history of previous stroke (cerebral vascular accident). Other significant factors predicting poor outcome included previous coronary artery bypass surgery, a history of congestive heart failure, a history of dialysis, advanced age, and female sex.

CONCLUSIONS

The degree of atherosclerosis in the descending aorta is not an independent predictor of poor in-hospital outcome after surgery involving cardiopulmonary bypass.

Asymptomatic cerebrovascular disease and systemic diagnosis in stroke, atherothrombosis as a disease of the vascular tree

Atherosclerosis is a chronic vascular disease of true epidemic proportions. It is the first cause of death in developed countries and responsible for one quarter of documented deaths worldwide. Arteriosclerotic vascular disease is a systemic process which affects different organs; principally the heart, brain, and peripheral artery system. Despite well-documented differences, all manifestations of the disease share the same risk factors; albeit with varying degrees of impact. The concept of asymptomatic cerebrovascular disease is an important one for clinicians who treat stroke patients. The development of new neuroimaging and vascular evaluation techniques has enabled the presence of apparently silent lesions to be detected and their progress monitored in follow-up. Ultrasonography techniques enable the identification of atheromatous disease. Asymptomatic involvement of the cerebral parenchyma consists of ischemia, leukoaraiosis, and silent hemorrhage and can be detected using the available radiological techniques such as cranial CT, magnetic resonance, or gradient echo magnetic resonance imaging. From the point of view of prevention, it is of considerable importance to identify diagnostic markers for arteriosclerosis in asymptomatic patients in some, if not all, vascular territories. In view of the natural history of this disease and the impact it has on society, there is an increasing need to identify and understand the risk factors or vascular disease risk markers, so that the stratification of risk of an individual patient or in a specific population can be established, appropriate cerebrovascular assessments conducted, and appropriate therapeutic intervention initiated.

Analysis of anatomic factors and age in patients undergoing carotid angioplasty and stenting

Recent data suggest that patient age >80 years may be associated with increased risk of periprocedural complications from carotid angioplasty and stenting (CAS). In this study, we analyzed anatomic risk factors in patients undergoing CAS based on age >80 or <80 years. Our hypothesis was that patients >80 would have more challenging anatomy. Between February 2003 and August 2004, 82 patients underwent CAS. Images for 57 lesions were available for review. Eighteen patients were > or =80 years old and 39 were <80. Cerebral protection devices, including EPI Filterwire, Percusurge, Accunet, and Angioguard, were used in all but two cases; and self-expanding stents (Wallstent, NexStent, Acculink, Precise) were placed in all. Arterial anatomic characteristics were assigned a score based on complexity and associated procedural risk. Characteristics evaluated using angiographic images were aortic arch elongation classification, arch calcification, common carotid/innominate stenosis, common carotid tortuosity, internal carotid tortuosity, index lesion length, index lesion calcification, and index lesion stenosis. Statistical analysis was performed using Fisher's exact test. CAS was successfully completed in 98% of cases. The two patients in whom we could not perform CAS were 79 and 83 years old. The anatomic characteristics that were statistically significantly more complex/severe in patients > or =80 were arch calcification (p = 0.045), common carotid/innominate stenosis (p = 0.023), common carotid tortuosity (p = 0.049), and internal carotid tortuosity (p = 0.032). There was no statistically significant difference in arch elongation classification, lesion length, lesion calcification, or stenosis severity (p = nonsignificant). Overall, patients > or =80 years had an increased incidence of complex anatomic risk factors compared to younger patients (p < 0.001). Cerebrovascular accident without residual deficits occurred in two patients; both were >80 years old. Complex arterial anatomy is more often present in patients >80 years and may explain the increased complication rates associated with CAS. Pre- or intraoperative consideration of these characteristics may help provide better risk assessment in candidates for CAS.

Improved Visualization of Aortic Intima-media Thickening with the Use of Perflutren Lipid Microspheres

BACKGROUND

Transesophageal echocardiography (TEE) has been used to diagnose atherosclerotic disease for patients who present with systemic embolic events. The primary aim of this study was to assess the supplemental value of echocardiographic contrast to standard TEE in identifying the aortic intima-medial thickness.

METHODS

An aorta phantom was used to validate the accuracy of border delineation with and without contrast during TEE imaging. In all, 44 patients underwent TEE imaging of the thoracic aorta with a subsequent administration of a 0.3-mL bolus of perflutren lipid microspheres (Definity). Precontrast and postcontrast images were analyzed semiquantitatively for border delineation and quantitatively for intima-medial thickness and cross-sectional area.

RESULTS

Wall thickness in the aortic phantom model with contrast was smaller, more accurate, and more reproducible to the true measurement. The clinical studies reflected similar results with average contrast intima-medial thickness measured at 0.15 +/- 0.08 cm and noncontrast at 0.18 +/- 0.08 cm (P < .01). The lateral wall showed the greatest improvement with a score of 1.23 increasing to an average of 1.82 (P < .001) with contrast. The medial, anterior, and posterior walls improved to an average 1.98, 1.39, and 2.0, respectively (P = .01).

CONCLUSIONS

Contrast agents provide better aortic intima-media enhancement during TEE.

Can transthoracic echocardiography with subcostal view predict abdominal aortic atherosclerosis?

BACKGROUND

Prompt detection of atherosclerosis (ATH) may profoundly impact therapy and patient outcome. During transthoracic echocardiography (TTE), subcostal views may suggest abdominal (ABD) aortic (AO) ATH, but this diagnosis may be inaccurate due to suboptimal images, which may in part relate to use of nonlinear probes. Therefore, we investigated the accuracy of TTE assessment of ABD AO ATH relative to transesophageal (TEE) AO images.

METHODS

Routine clinical TTE and TEE studies of 100 patients (44 men), aged 30-92 years old, were reviewed retrospectively and blindly. ABD AO ATH by TTE was graded qualitatively as grade (GR) 0 = smooth wall surface; GR 1, 2, and 3 = mild, moderate, and severe irregularities, respectively; and GR 4 = mobile/complex plaque. TEE images were graded quantitatively as the maximal intimal-medial, or plaque thickness, imaged in the AO arch or descending AO, as: GR 0 <or= 1.5 mm, GR 1 = 1.5-2.4 mm, GR 2 = 2.5-4 mm, GR 3 = >4 mm, or GR 4 = mobile/complex plaque >4 mm. TTE ability to detect the presence (>GR 0) of ABD AO ATH on TEE was measured in terms of sensitivity (SN), specificity (SP), positive (PPV) and negative (NPV) predictive accuracy-in patients with adequate and suboptimal images-compared to TEE.

RESULTS

TTE image quality was adequate in 75 patients and suboptimal in 25. SP and PPV of grading ATH by TTE were directly related to grading by TEE; however, SN and NPV demonstrated an inverse relationship with increasing grading of ATH. TTE correlated with TEE grading with an r = 0.42 (P = 0.0001) for patients (n = 75) with adequate TTE and r = 0.32 (P = 0.001) for all patients (n = 100), including those with suboptimal TTE images.

CONCLUSION

Routine TTE imaging is usually correct in predicting ATH on TEE, but with modest error, it should generally not be relied on as a definitive test for ATH. Adequate image quality improves the correlation of TEE and TTE grading of ABD ATH, and more severe ATH on TTE is more predictive of ATH on TEE.

Off-pump coronary artery bypass grafting reduces postoperative neurologic complications

OBJECTIVE

Complications occurring after coronary artery bypass graft (CABG) surgery, particularly neurologic damage, have been mainly correlated with the use of cardiopulmonary bypass (CPB). The aim of this work was to compare postoperative outcomes of patients undergoing CABG surgery, with or without the use of CPB, focusing on neurologic events.

DESIGN

Observational study.

SETTING

University tertiary care hospital.

PARTICIPANTS

Two thousand seven hundred and forty consecutive patients who underwent CABG surgery in the period January 1998 to January 2003.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For 738 patients, the operation was performed off-pump (OP group), and for 2002 patients CPB was used (CPB group). OP and CPB groups were compared with regard to preoperative status, anesthetic management, and postoperative outcomes, by means of univariate and multivariate analyses. Surgeons' propensity to operate off-pump was based on patients' age, renal conditions, and hemodynamics. Univariate and multivariate analyses showed that CPB was associated with a higher incidence of type I neurologic events compared with OP technique (2.1% versus 0.9%, odds ratio [OR]: 2.6, 95% confidence interval [CI], 1.2-5.9). A history of previous stroke (OR: 2.7, 95% CI, 1.2-5.9) and advanced age (OR: 1.06 per year, 95% CI, 1.02-1.09) were additional independent predictors of postoperative type I neurologic events.

CONCLUSIONS

In the authors' experience, off-pump CABG surgery offers some benefits compared with CPB in respect to major neurologic complications.

Risk factors for late stroke after coronary artery bypass grafting

BACKGROUND

Postoperative stroke is a severe complication immediately after coronary artery bypass grafting, and it significantly deteriorates the postoperative quality of life if it occurs in the long term. It was the aim of our study to determine factors associated with the occurrence of new strokes during long-term follow-up after coronary artery bypass grafting.

METHODS

From 387 of 500 patients undergoing coronary artery bypass grafting (age, 67 years [33-84 years]; 76% male) who had intraoperative epiaortic ultrasonography for assessment of ascending aortic wall thickness, a complete follow-up regarding postoperative stroke was achieved. The median follow-up time was 52 months (9-74 months).

RESULTS

A stroke occurred in 26 (7%) of 387 patients, and the cumulative freedom from stroke was 99%, 95%, and 89% after 1, 3, and 5 years, respectively. A significantly lower freedom from stroke was present in patients with an age of 70 years or more (P = .007), preoperative unstable angina (P = .031), chronic obstructive pulmonary disease (P = .009), carotid artery disease (P < .001), preoperative history of neurologic events (P < .001), and a maximum ascending aortic wall thickness of 4 mm or more (P = .010). Multivariate analysis revealed preoperative history of neurologic events (P = .021) to be an independent risk factor.

CONCLUSION

Patients with ascending aortic atherosclerosis, older age (> or =70 years), preoperative unstable angina, chronic obstructive pulmonary disease, and carotid artery disease are at risk for late postoperative stroke after coronary artery bypass grafting. A history of neurologic events is of special predictive importance.

Atherosclerosis of the ascending aorta as a major determinant of the outcome of cardiac surgery

Epiaortic ultrasonography has high sensitivity for the detection of atherosclerosis. In several studies, the technique has identified atherosclerosis of the ascending aorta as the major risk factor for stroke after cardiac surgery. The level of risk depends on the presence, location and extent of disease when the ascending aorta is surgically manipulated. This knowledge enables clinicians to focus on the diagnostic and surgical technique and to consider the various options. Routine use of intraoperative epiaortic ultrasonography should be applied so that surgical manipulation of the ascending aorta can be reduced or, if possible, avoided in patients with atherosclerosis of the ascending aorta. Alternatively, if major manipulation such as clamping must be performed in the presence of severe atherosclerosis, the use of intra-aortic filters could be considered.

The use of the SonoSite ultrasound device for intraoperative evaluation of the aorta

OBJECTIVE

Neurologic complications remain a significant cause of morbidity and mortality in cardiac surgery. Risk factors for neurologic injuries include the presence of atheromatous disease in the aorta. Epiaortic ultrasound has been shown to be superior in detecting the extent and location of atheromatous disease. The SonoSite Corporation (Bothell, WA) has recently introduced an affordable, portable, high-resolution ultrasound device. This new device was compared with the Hewlett-Packard Sonos 5550 ultrasound device (currently manufactured by Philips, Andover, MA) to determine suitability for this purpose.

DESIGN

Prospective, serial comparison of 2 devices.

SETTING

University hospital.

PARTICIPANTS

Fifty consecutive cardiac surgery patients.

INTERVENTIONS

Intraoperative epiaortic ultrasound images were obtained using a SonoSite 180 Plus ultrasound device and a Hewlett-Packard Sonos 5500 ultrasound device. Three observers graded recorded images based on extent of atheromatous disease.

MEASUREMENTS AND MAIN RESULTS

Two patients were excluded because of errors in recording images. For the 48 remaining patients, consensus (median) grades had an observed agreement of 93.6% compared with a chance agreement of 67.7%. This correlates to a kappa value of 0.80 or near-excellent agreement.

CONCLUSIONS

The near-excellent agreement of the 2 devices is acceptable, thus providing a unique opportunity to expand the use of epiaortic ultrasound imaging.

Risk Factors for Stroke Following Coronary Artery Bypass Operations

BACKGROUND

Although the overall complication rates have been decreased significantly in recent years, stroke rates still remain high in patients undergoing coronary bypass operations. This study is designed to evaluate the risk factors for stroke in patients who had undergone coronary artery bypass surgery in an 8-year period in our clinic.

METHODS

Between 1995 and 2003, 8547 coronary artery operations under cardiopulmonary bypass were performed. Retrospective analysis of the patient files revealed that 75 (0.9%) patients had stroke in the early postoperative period.

RESULTS

Mean age of these patients was 62.3 +/- 9.5 years, and 54 (72%) were males. Stroke rate was 1.2% between 1995 and 1998 and this was significantly higher from the stroke rate (0.7%) of the period 1998 to 2003 (p = 0.03). Major technical differences between these two periods were the routine application of preoperative carotid arteries Doppler evaluation and intraoperative epiaortic echocardiography after 1998. Higher age (p = 0.000), female sex (p = 0.005), smoking (p = 0.03), presence of diabetes mellitus (p = 0.01), hypertension (p = 0.008), and left main coronary artery disease (p = 0.001), carotid surgery (p = 0.000), and peripheral vascular disease (p = 0.049) were identified as important risk factors in univariate analysis for stroke development. Higher age (p = 0.000; OR = 21.38), left main coronary artery disease (p = 0.007; OR = 7.26), peripheral vascular disease (p = 0.050; OR = 3.08), and operation date before 1998 (p = 0.012; OR = 6.33) were identified as important risk factors in logistic regression analysis. According to intraoperative epiaortic ultrasonography, operative strategy was changed in 9% of patients. Thirty-seven (49.3%) of the stroke patients died. Female sex (p = 0.023; OR = 5.18) and preoperative hypertension (p = 0.045; OR = 4.03) were observed as significant risk factors for mortality after stroke.

CONCLUSION

Development of stroke is one of the major reasons of mortality after coronary artery bypass operations. It is essential to take all the measures to prevent this complication, especially in patients with known risk factors. Evaluation of carotid arteries prior to operation and application of routine intraoperative epiaortic echocardiography may in part eliminate stroke.

Perioperative multimodality neuromonitoring: an overview

Neurologic damage after cardiac surgery remains an important cause of postoperative morbidity. In addition to a wide variety of procedural risks, patient-specific factors such as the presence of extracranial or intracranial atherosclerotic disease, either alone or together, have a fundamental impact on the risk of brain injury developing after cardiovascular surgery. A variety of neurophysiologic monitoring techniques have been used during cardiovascular surgery in hopes of averting neurologic injury. In this issue of Seminars, the strengths and weaknesses of each are discussed by a group of highly experienced clinical investigators. The ultrasound techniques of epiaortic scanning and continuous transcranial Doppler insonation of large intracranial arteries can alter perfusion management and surgical habits to markedly decrease the delivery of atherosclerotic, lipoidal, and gaseous microemboli to the brain and other vital organs. Cerebral hypoperfusion from unrecognized cerebral venous obstruction, inadequate mean arterial pressure, or hypocapnic cerebral alkalosis can be identified by transcranial near-infrared spectroscopy, electroencephalogram, and sensory evoked potentials. Compromise of spinal cord perfusion during the repair of thoracoabdominal aneurysms may be identified and corrected with the guidance provided by transcranial electric motor-evoked potentials. Quantitative electroencephalogram and auditory evoked potential indices also appear beneficial in producing objective measures of the hypnotic component of anesthesia. These neuromonitoring methods, particularly when used in concert, can improve overall patient outcome and reduce hospital length of stay.

Atheroma of the aortic arch: an important and poorly recognised factor in the aetiology of stroke

Atrial fibrillation and severe carotid-artery stenosis are well-characterised risk factors for stroke; each is present in about a fifth of patients. The identification of such risk factors in patients is important because their presence calls for specific secondary prevention strategies. One region of the circulation that has received limited attention as a source of thrombus is the aortic arch. However, aortic arch atheroma is a common post-mortem finding, and it seems reasonable to speculate that atheroma might give rise to thrombi with distal embolism to the arterial tree, including the cerebral circulation. Here we review the evidence for aortic-arch atheroma as an important independent risk factor for stroke, and show that studies of the risk of stroke indicate a four times greater odds of stroke in patients with severe arch atheroma.

Neuroprotection in cardiac surgery

This article reviews past and present neuroprotective efforts and outlines a framework for the future development of techniques for neuroprotection during cardiac surgery.

Modification of surgical technique for ascending aortic atherosclerosis: impact on stroke reduction in coronary artery bypass grafting

OBJECTIVE

Use of epiaortic scanning in coronary surgery is still a matter of debate. It is unclear whether the findings obtained by epiaortic scanning lead to effective changes in surgical technique that may reduce stroke rates.

METHODS

Epiaortic scanning was performed in 352 patients undergoing primary coronary artery bypass grafting before opening the pericardium using a 7.5-MHz ultrasonic probe. In the presence of moderate atherosclerosis (maximum aortic wall thickness of 3 to 5 mm), primarily single aortic crossclamping was carried out. In cases of severe sclerosis (maximum aortic wall thickness > 5 mm), aortic no-touch techniques on the beating heart were used.

RESULTS

The degree of ascending aortic atherosclerosis was normal or mild in 151 patients (42.9%), moderate in 167 patients (47.5%), and severe in 34 patients (9.6%). The operative technique was modified in 31.1% of patients with moderate aortic sclerosis and in 91.2% of patients with severe aortic sclerosis. Perioperative mortality was 0.0% for mild disease, 3.0% for moderate disease, and 8.8% for severe disease (P =.005). Corresponding stroke rates reached 2.0%, 2.4%, and 2.9% (P =.935). Logistic regression adjusting for EuroSCORE showed that ascending aortic atherosclerosis was an independent predictor of perioperative mortality (P =.013, odds ratio 1.67, confidence interval 1.11-2.50). The influence of aortic disease on the stroke prevalence was probably due to chance (P =.935), demonstrating a potentially positive effect of operative modifications concerning stroke caused by aortic manipulation.

CONCLUSIONS

We conclude that intraoperative screening of coronary artery bypass grafting patients by epiaortic scanning can reveal useful information about the operative risk and with an aortic no-touch concept, perioperative stroke rates in high-risk patients may be lower than predicted.

Aortic Source of Brain Embolism

Aortic arch atheroma has more recently been identified as an independent risk factor for ischemic stroke. Initially, this was a result of careful autopsy observations, then followed by a series of in vivo studies in which aortic arch atheroma was identified by transesophageal echocardiography. The association of aortic arch atheroma with ischemic stroke is most likely causal, given that the stroke risk increases with increasing thickness of arch atheroma. There is quite a sharp increase in stroke risk for atheroma of 4 mm or greater compared with lesser thicknesses. The clinical diagnosis is suggested when transient ischemic attack or ischemic stroke has occurred in which no obvious cardiac or arterial source of embolism is found. The presence of aortic arch atheroma is usually detected by transesophageal echocardiography and sometimes by magnetic resonance imaging or computed tomography. There is uncertainty about clinical management, particularly for secondary prevention. Options include the use of antiplatelet agents, anticoagulants, thrombolysis, or surgery. The latter two options have only been described rarely in case reports. Of the less invasive approaches, combination antiplatelet therapy with aspirin and clopidogrel is favored, or the use of warfarin. The Aortic arch Related Cerebral Hazard (ARCH) trial is being conducted to determine which of these is more effective in minimizing a composite outcome cluster of ischemic stroke, intracranial hemorrhage, myocardial infarction, peripheral embolism, or vascular death. Other more general management strategies should include reasonably aggressive risk factor control with blood pressure and lipid-lowering therapies and, if indicated, careful diabetic control.

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.

Endoluminal AAA repair using intravascular ultrasound for graft planning and deployment: a 2-year community-based experience

PURPOSE

To examine the effectiveness of intravascular ultrasound (IVUS) and digital subtraction angiography (DSA) for preoperative planning and intraoperative deployment of stent-grafts to treat abdominal aortic aneurysms.

METHODS

One hundred seventy patients (143 men; mean age 73.6+/-7.2 years, range 51-89) underwent successful DSA and IVUS to determine suitability for stent-graft repair. Patients subsequently received the AneuRx (n=157) or Ancure (n=13) device; intraprocedural IVUS was used to survey the proximal endograft for proper apposition to the aortic wall.

RESULTS

Reliable preoperative IVUS measurements were obtained in all patients. Plaque morphology was assessed in 140 (82.3%) aortic necks; in 36 (25.7%), preoperative IVUS showed high-grade atherosclerotic plaque in the nonaneurysmal abdominal aortic neck. The procedure was successful in 168 (98.8%) cases (1 [0.6%] acute conversion and 1 access failure). There were 2 (1.2%) periprocedural deaths related to bowel ischemia. Four (2.3%) patients developed graft occlusion/kinking and 2 (1.2%) developed renal failure requiring dialysis within 30 days. Multivariate logistic regression analysis revealed that female gender (p=0.0247), a short nonaneurysmal aortic neck (p=0.0185), and presence of high-grade atherosclerotic plaque (p=0.0185) correlated with major acute complications. Over a mean 10.4-month follow-up (range 1-25), 11 patients died of unrelated causes; there was no known AAA rupture or device failure. The Kaplan-Meier estimate of survival at 1 year was 91.0%+/-2.8%. Sixteen (9.4%) patients underwent 17 secondary procedures for endoleak or graft limb occlusion at a mean 5.4 months after stent-graft repair (freedom from secondary intervention at 1 year 86.5%+/-3.2%).

CONCLUSIONS

Our findings suggest that IVUS may identify patients at increased risk of major adverse complications following endovascular repair. The combination of IVUS and DSA for endoluminal stent-graft planning and placement provides excellent short- and mid-term patient outcomes.