Coronary artery bypass performed without the use of cardiopulmonary bypass is associated with reduced cerebral microemboli and improved clinical results

Clinical relevance of transcranial Doppler in a cardiac surgery setting: embolic load predicts difficult separation from cardiopulmonary bypass

BACKGROUND

During cardiac surgery, transcranial Doppler (TCD) represents a non-invasive modality that allows measurement of red blood cell flow velocities in the cerebral arteries. TCD can also be used to detect and monitor embolic material in the cerebral circulation. Detection of microemboli is reported as a high intensity transient signal (HITS). The importance of cerebral microemboli during cardiac surgery has been linked to the increased incidence of postoperative renal failure, right ventricular dysfunction, and hemodynamic instability. The objective of this study is to determine whether the embolic load is associated with hemodynamic instability during cardiopulmonary bypass (CPB) separation and postoperative complications.

METHODS

A retrospective single-centre cohort study of 354 patients undergoing cardiac surgery between December 2015 and March 2020 was conducted. Patients were divided in tertiles, where 117 patients had a low quantity of embolic material (LEM), 119 patients have a medium quantity of microemboli (MEM) and 118 patients who have a high quantity of embolic material (HEM). The primary endpoint was a difficult CPB separation. Multivariate logistic regression was used to determine the potential association between a difficult CPB separation and the number of embolic materials.

RESULTS

Patients who had a difficult CPB separation had more HITS compared to patients who had a successful CPB separation (p < 0.001). In the multivariate analysis, patients with MEM decreased their odds of having a difficult CPB weaning compared to patients in the HEM group (OR = 0.253, CI 0.111-0.593; p = 0.001). In the postoperative period patients in the HEM group have a higher Time of Persistent Organ Dysfunction (TPOD), a longer stay in the ICU, a longer duration under vasopressor drugs and a higher mortality rate compared to those in the MEM and LEM groups.

CONCLUSION

The result of this study suggests that a high quantity of cerebral embolic material increases the odds of having a difficult CPB separation. Also, it seems to be associated to more complex surgery, a longer CPB time, a higher TPOD and a longer stay in the ICU. Six out of eight patients who died in this cohort were in the HEM group.

Off-pump vs. on-pump bypass surgery grafting in diabetic patients with three-vessel disease: a propensity score matching study

Background

Controversy exists regarding the advantages and risks of off-pump vs. on-pump coronary artery bypass grafting (CABG) for patients with diabetes. We therefore compare the early clinical outcomes of off-pump vs. on-pump procedures for diabetic patients with three-vessel disease.

Materials and methods

We conducted a retrospective analysis of clinical data obtained from 548 diabetic patients with three-vessel coronary artery disease who underwent isolated CABG between January 2016 and June 2020. To adjust the differences of baseline characteristics between the off-pump CABG (OPCAB) and on-pump CABG (ONCAB) groups, propensity score matching (PSM) was used. Following 1:1 matching, we selected 187 pairs of patients for further comparison of outcomes within the first 30 days after surgery.

Results

The preoperative characteristics of the patients between the two groups were clinically comparable after PSM. The OPCAB group exhibited a significantly higher incidence of incomplete revascularization (27.3% vs. 14.4%; P = 0.002) compared with the ONCAB group. No differences were seen in mortality within 30 days between the matched groups (1.1% vs. 3.7%; P = 0.174). Notably, the OPCAB group had a lower risk of respiratory failure or infection (2.1% vs. 7.0%; P = 0.025), less postoperative stroke (1.1% vs. 4.8%; P = 0.032), and reduced postoperative ventilator assistance time (35.8 ± 33.7 vs. 50.9 ± 64.8; P = 0.005).

Conclusion

OPCAB in diabetic patients with three-vessel disease is a safe procedure with reduced early stroke and respiratory complications and similar mortality rate, myocardial infarction, and renal failure requiring dialysis to conventional on-pump revascularization.

Stroke and mortality rates after off-pump vs. pump-assisted/no-clamp coronary artery bypass grafting

BACKGROUND

Ascending aorta manipulation during on-pump coronary artery bypass grafting (CABG) surgery can release embolic matter and may cause stroke. Strategies for lowering the stroke rate associated with coronary artery bypass grafting surgery include off-pump surgery without cardiopulmonary bypass and pump-assisted surgery with minimal aortic manipulation (i.e., without aortic cross-clamping). We examined whether one approach is superior to the other in reducing stroke and perioperative mortality rates.

METHODS

We reviewed consecutive elective, urgent, and emergency off-pump/no-bypass and pump-assisted/no-clamp coronary artery bypass grafting procedures performed by a single surgeon at our institution from June 2011 through October 2017.

RESULTS

Of 570 patients analyzed, 395 (69.3%) underwent off-pump/no-bypass surgery, 43 (7.5%) underwent pump-assisted/no-clamp surgery, and 132 (23.2%) transitioned mid-procedure from off-pump/no-bypass to pump-assisted/no-clamp surgery. Patients who were >70 years old, were female, or had diabetes, cardiomegaly, or a history of myocardial infarction or congestive heart failure were more likely to undergo pump-assisted/no-clamp surgery or the combined technique. None of the pump-assisted/no-clamp patients had a stroke, versus 0.3% of the off-pump/no-bypass patients and 0.8% of the combination patients. Stroke and in-hospital mortality rates did not differ by technique.

CONCLUSIONS

A hybrid strategy incorporating off-pump, pump-assisted, and combined off-pump/pump-assisted techniques achieved very low stroke rates in patients undergoing coronary revascularization. Perioperative mortality was similar for all three techniques. Avoiding aortic clamping may be crucial for decreasing CABG-related stroke rates. Off-pump/no-bypass surgery had no significant advantage over the pump-assisted/no-clamp or combined techniques in reducing the stroke rate after coronary artery bypass grafting surgery.

Preoperative treatment with clopidogrel and ticagrelor on bleeding complications in off-pump coronary artery bypass grafting

BACKGROUND

Dual antiplatelet therapy (DAPT) consisting of acetylsalicylic acid and clopidogrel or ticagrelor increased bleeding complications in patients undergoing coronary artery bypass grafting (CABG). We aimed to compare the bleeding risks between patients treated with clopidogrel and ticagrelor preoperatively and investigate the influence of discontinuation of clopidogrel and ticagrelor on bleeding risk in off-pump CABG (OPCABG).

METHODS

We conducted a retrospective analysis of patients with DAPT who underwent OPCABG. The propensity score matching was performed given the baseline differences between clopidogrel- and ticagrelor-treated patients. Bleeding was assessed by chest tube drainage volume and universal definition of perioperative bleeding.

RESULTS

This study included 836 patients. Five hundred and fifty patients were treated with clopidogrel and 286 patients treated with ticagrelor before surgery. After matching, 275 patients treated with clopidogrel and 275 patients with ticagrelor were included. There were no significant differences in bleeding between clopidogrel and ticagrelor group. Patients who discontinued clopidogrel before surgery <3 d had a higher risk of severe perioperative bleeding compared with those who discontinued ≥5 d (16.4 % vs. 5.0 %, P = 0.045). By contrast, the risk of severe perioperative bleeding was comparable among patients who discontinued ticagrelor for <3 d, ≥3-5 d and ≥5 d preoperatively (16.2 % vs. 9.1 % vs. 10.1 %, P = 0.317). The multivariable analysis confirmed that time since discontinuation (<3 d vs. ≥5 d: OR = 2.732, 95 % CI: 1.332-5.605, P = 0.006) but not the types of P2Y₁₂ receptor antagonist was an independent predictor for severe perioperative bleeding.

CONCLUSIONS

There were no significant differences in severe perioperative bleeding between clopidogrel and ticagrelor groups. Discontinuation of clopidogrel <3 d before OPCABG increased the risk of severe perioperative bleeding.

Off-Pump versus Conventional Coronary Artery Bypass Grafting: A Meta-Analysis and Consensus Statement from the 2004 ISMICS Consensus Conference

Background

The purpose of this evidence-based consensus statement is to systematically review and meta-analyze the randomized and nonrandomized evidence comparing off-pump (OPCAB) to conventional coronary artery bypass (CCAB) surgery and to provide consensus on the role of OPCAB in low- and high-risk surgical patients.

Methods and Results

This consensus conference was conducted according to the American College of Cardiology (ACC)/American Heart Association (AHA) standards for development of clinical practice guidelines. The Steering Committee collated all published studies of OPCAB versus CCAB through May 2004 and developed six questions central to controversies surrounding OPCAB surgery in mortality, morbidity, and resource utilization. For mixed-risk patient populations, meta-analysis of 37 randomized clinical trials (3,369 patients, Level A) reported across a total of 53 papers, and two meta-analyses of nonrandomized trials (Level B) comparing OPCAB versus CCAB were identified. For high-risk patient populations, we performed a meta-analysis of 3 randomized and 42 nonrandomized trials (26,349 patients, Level B).

Conclusion

Meta-analysis of Level A and B evidence provided the basis for the following consensus statements in patients undergoing surgical myocardial revascularization: (1) OPCAB should be considered a safe alternative to CCAB with respect to risk of mortality [Class I, Level A]; (2) With appropriate use of modern stabilizers, heart positioning devices, and adequate surgeon experience, similar completeness of revascularization and graft patency can be achieved [Class IIa, Level A]; (3) OPCAB is recommended to reduce perioperative morbidity [Class I, Level A]; (4) OPCAB may be recommended to minimize midterm cognitive dysfunction [Class IIa, Level A]; (5) OPCAB should be considered as an equivalent alternative to CCAB in regard to quality of life [Class I, Level A]; (6) OPCAB is recommended to reduce the duration of ventilation, ICU and hospital stay, and resource utilization [Class I, Level A]; (7) OPCAB should be considered in high-risk patients to reduce perioperative mortality, morbidity, and resource utilization [Class IIa, Level B].

Intraoperative tranexamic acid is associated with postoperative stroke in patients undergoing cardiac surgery

BACKGROUND

Stroke is a devastating and potentially preventable complication of cardiac surgery. Tranexamic acid (TXA) is a commonly antifibrinolytic agent in cardiac surgeries with cardiopulmonary bypass (CPB), however, there is concern that it might increase incidence of stroke after cardiac surgery. In this retrospective study, we investigated whether TXA usage could increase postoperative stroke in cardiac surgery.

METHODS

A retrospective study was conducted from January 1, 2010, to December 31, 2015, in 2,016 patients undergoing cardiac surgery, 664 patients received intravenous TXA infusion and 1,352 patients did not receive any antifibrinolytic agent. Univariate and propensity-weighted multivariate regression analysis were applied for data analysis.

RESULTS

Intraoperative TXA administration was associated with postoperative stroke (1.7% vs. 0.5%; adjusted OR, 4.11; 95% CI, 1.33 to 12.71; p = 0.014) and coma (adjusted OR, 2.77; 95% CI, 1.06 to 7.26; p = 0.038) in cardiac surgery. As subtype analysis was performed, TXA administration was still associated with postoperative stroke (1.7% vs. 0.3%; adjusted OR, 5.78; 95% CI, 1.34 to 27.89; p = 0.018) in patients undergoing valve surgery or multi-valve surgery only, but was not associated with postoperative stroke (1.7% vs. 1.3%; adjusted OR, 5.21; 95% CI, 0.27 to 101.17; p = 0.276) in patients undergoing CABG surgery only. However, TXA administration was not associated with postoperative mortality (adjusted OR, 1.31; 95% CI, 0.56 to 3.71; p = 0.451), seizure (adjusted OR, 1.13; 95% CI, 0.42 to 3.04; p = 0.816), continuous renal replacement therapy (adjusted OR, 1.36; 95% CI, 0.56 to 3.28; p = 0.495) and resternotomy for postoperative bleeding (adjusted OR, 1.55; 95% CI, 0.55 to 4.30; p = 0.405). No difference was found in postoperative ventilation time (adjusted B, -1.45; SE, 2.33; p = 0.535), length of intensive care unit stay (adjusted B, -0.12; SE, 0.25; p = 0.633) and length of hospital stay (adjusted B, 0.48; SE, 0.58; p = 0.408).

CONCLUSIONS

Based on the 5-year experience of TXA administration in cardiac surgery with CPB, we found that postoperative stroke was associated with intraoperative TXA administration in patients undergoing cardiac surgery, especially in those undergoing valve surgeries only. This study may suggest that TXA should be administrated according to clear indications after evaluating the bleeding risk in patients undergoing cardiac surgery, especially in those with high stroke risk.

Off-pump versus on-pump coronary artery bypass grafting in patients with diabetes: a meta-analysis

AIMS

The effects of off-pump CABG (OFF-CABG) versus on-pump CABG (ON-CABG) in diabetic patients remain controversial. The aim of our study was to compare mortality and postoperative morbidity between OFF-CABG and ON-CABG for diabetic patients.

METHODS

Electronic databases including PubMed, EMBASE and Cochrane Library for studies investigating clinical outcomes of OFF-CABG versus ON-CABG in diabetic patients were searched, collecting data from inception until June 2016. We pooled the odds ratios from individual studies and performed heterogeneity, quality assessment and publication bias analysis.

RESULTS

A total of 543,220 diabetic patients in 10 studies were included. The overall mortality (OR, 0.87; 95% CI, 0.58-1.31; p = 0.50) was comparable between the OFF-CABG and ON-CABG. OFF-CABG was associated with significantly fewer cerebrovascular accidents (OR, 0.45; 95% CI, 0.31-0.65; p < 0.0001), bleeding complications (OR, 0.59; 95% CI, 0.43-0.80; p < 0.001) and pulmonary complications. However, no differences in myocardial infarction (OR, 0.76; 95% CI, 0.52-1.12; p = 0.16), renal failure (OR, 0.74; 95% CI, 0.50-1.11; p = 0.14) and other postoperative morbidity outcomes were found.

CONCLUSIONS

OFF-CABG significantly reduces the incidence of postoperative cerebrovascular accidents and bleeding complications compared with ON-CABG in diabetic patients. No differences were found regarding mortality, myocardial infarction and renal failure between these two techniques. Our study suggests that OFF-CABG may be an optimal strategy for diabetic patients although adequately powered randomized trials are needed to further verify the finding.

Aortic Arch Atheroma: Stroke Reduction in Cardiac Surgical Patients

Cardiac surgery is increasingly performed on elderly patients with extensive coronary artery abnormalities who have impaired left ventricular function, decreased physiologic reserve, and multiple comorbid conditions. Considerable numbers of these patients develop perioperative neurologic complications ranging from subtle cognitive dysfunction to more evident postoperative confusion, delirium, and, less commonly, clinically apparent stroke. Magnetic resonance imaging studies have elucidated that a considerable number of patients have new ischemic brain infarcts, particularly after conventional coronary artery bypass graft surgery. Mechanisms of cerebral injury during and after cardiac surgery are discussed. Intraoperative transesophageal echocardiography and epiaortic scanning for detection of atheromatous disease of the proximal thoracic aorta is paramount in identifying patients at high risk from neurologic injury. It is important to recognize that our efforts to minimize neurologic injury should not be limited to the intraoperative period. Particular efforts should be directed to temperature management, glycemia control, and pharmacologic neuroprotection extending into the postoperative period. Preoperative magnetic resonance angiography may be of value for screening patients with significant atheroma of the proximal thoracic aorta. It is likely that for patients with no significant atheromatous disease, conventional coronary artery revascularization is the most effective long-term strategy, whereas patients with atheromatous thoracic aorta may be better managed with beating heart surgery, hybrid techniques, or medical therapy alone. Patient stratification based on the aortic atheromatic burden should be addressed in future trials designed to tailor treatment strategies to improve long-term outcomes of coronary heart disease and reduce the risks of perioperative neurologic injury.

The future of off-pump coronary artery bypass grafting: a North American perspective

Off-pump coronary artery bypass graft (OPCAB) is currently performed routinely in a minority of specialized centers and in many more centers, utilized only when a porcelain aorta mandates a no-touch aortic technique. The OPCAB literature can be summarized as follows: (I) large-scale randomized trials in relatively low risk patients that include surgeons with a range of experience demonstrating no consistent beneficial differences in major cardiovascular and cerebrovascular outcomes but lower transfusion rates and shorter length of stay, tempered by some reports of higher rates of incomplete revascularization and lower rates of long term graft patency; (II) smaller randomized controlled trials (RCTs) from highly specialized programs demonstrating equivalent or superior outcomes with OPCAB and similar completeness of revascularization and graft patency; and (III) observational data from large databases demonstrating a consistent benefit of OPCAB, especially in higher-risk patient subsets. Our rationale for OPCAB remains that if complete and precise revascularization can be safely and routinely accomplished, then the patient should benefit by avoiding the morbidities that can be attributed to aortic cannulation/clamping, cardiopulmonary bypass (CPB), hemodilution, hypothermia and global myocardial ischemia/cardioplegia. We further believe that OPCAB procedures should emphasize the use of arterial grafts to optimize long term patency and minimize aortic manipulation to limit the risk of stroke. Moving forward, the off-pump surgical community and specialty societies must address the challenge of training surgeons and their teams to master this technically demanding procedure. Furthermore, OPCAB opens the door to minimally-invasive surgical revascularization via hybrid coronary revascularization (HCR). A large NIH-funded RCT is currently underway to determine whether hybrid revascularization can offer a superior alternative to multi-vessel percutaneous coronary intervention for patients with low SYNTAX score and proximal LAD disease.

Current outcomes of off-pump versus on-pump coronary artery bypass grafting: evidence from randomized controlled trials

Coronary artery bypass grafting remains the standard treatment for patients with extensive coronary artery disease. Coronary surgery without use of cardiopulmonary bypass avoids the deleterious systemic inflammatory effects of the extracorporeal circuit. However there is an ongoing debate surrounding the clinical outcomes after on-pump versus off-pump coronary artery bypass (ONCAB versus OPCAB) surgery. The current review is based on evidence from randomized controlled trials (RCTs) and meta-analyses of randomized studies. It focuses on operative mortality, mid- and long-term survival, graft patency, completeness of revascularisation, neurologic and neurophysiologic outcomes, perioperative complications and outcomes in the high risk groups. Early and late survival rates for both OPCAB and ONCAB grafting are similar. Some studies suggest early poorer vein graft patency with off-pump when compared with on-pump, comparable midterm arterial conduit patency with no difference in long term venous and arterial graft patency. A recent, pooled analysis of randomised trials shows a reduction in stroke rates with use off-pump techniques. Furthermore, OPCAB grafting seems to reduce postoperative renal dysfunction, bleeding, transfusion requirement and respiratory complications while perioperative myocardial infarction rates are similar to ONCAB grafting. The high risk patient groups seem to benefit from off-pump coronary surgery.

The dynamic bubble trap reduces microbubbles in extracorporeal circulation and high intensity transient signals in the middle cerebral artery: a case report

Microemboli during extracorporeal circulation (ECC) might be a reason for postoperative neuropsychological dysfunction. This case report shows that reduction of microbubbles in the arterial line, as well as high intensity transient signals (HITS) in the middle cerebral artery (MCA), could be accomplished by use of a dynamic bubble trap (DBT) during routine coronary artery bypass graft (CABG) surgery in a 63-year-old male. The DBT was placed after the arterial filter, an ultrasound Doppler device was used for detection of microemboli before and after the DBT. HITS were measured by a transcranial ultrasound Doppler in both MCAs. For first 32 min of ECC, the DBT was excluded; 54 916 microbubbles and 507 HITS were counted. In the next 30 min, blood flow was directed through the DBT. This led to a significant reduction of microbubbles from 55 888 to 18 237; accordingly, only 120 HITS were registered. A DBT, integrated in ECC for routine CABG, effectively reduces air bubbles, thus protecting the cerebrovascular system from micro-embolization, as demonstrated by lower HITS counts.

Retrospective evaluation of the effect of carotid artery stenosis on cerebral oxygen saturation during off-pump coronary artery bypasses grafting in adult patients

Background

It is unknown whether cerebral oxygenation in patients with carotid artery stenosis (CAS) undergoing off-pump coronary artery bypass grafting (CABG) differs from that in patients without CAS. Thus, the effect of the presence of CAS ≥ 50 % on cerebral oxygenation during off-pump CABG in adult patients was evaluated retrospectively.

Methods

Eleven patients with CAS ≥ 50 % and 14 patients without CAS ≥ 50 % were enrolled. Regional cerebral tissue oxygen saturation (rSO₂) was quantified using near-infrared spectroscopy. Mean arterial pressure, cardiac index, central venous pressure (CVP), and rSO₂ at specific points were collected, and significant changes in each parameter were detected using repeated analysis of variance. Mean rSO₂ and minimum rSO₂ during anastomosis were analyzed by one-way analysis of variance. Multiple logistic regression analysis was used to estimate the odds ratio (OR) with 95 % confidence interval (CI) for cerebral desaturation (a decrease in rSO₂ ≥ 10 % from preoperative value).

Results

Two patients with CAS ≥ 50 % who received complete carotid artery stenting preoperatively were excluded from the analyses. In both patients with and without CAS, a decrease in rSO₂ and cardiac index and an increase in CVP were observed during anastomosis. Mean (SD) maximum decrease in rSO₂ from preoperative value was 9.2 (12.7) % on the left side and 8.1 (11.7) % on the right side in patients with CAS ≥ 50 %, and 13.5 (11.3) % on the left side and 16.1 (9.8) % on the right side in patients without CAS ≥ 50 % (p = 0.316). Neurological complications were not identified in both patients with and without CAS ≥ 50 %. In multiple logistic regression analysis, CAS ≥ 50 % was not associated with an increased risk of cerebral desaturation (OR 0.160, 95 % CI 0.036–0.707, p = 0.016), and rSO₂ decreased with decreasing cardiac index < 2.0 l/min/m² (OR 3.287, 95 % CI 2.218–5.076, p < 0.001).

Conclusions

CAS ≥ 50 % was not an independent risk factor of cerebral desaturation during off-pump CABG. Our results suggest that maintaining cardiac output can prevent a decrease in cerebral oxygenation in both patients with and without CAS ≥ 50 %.

Serum S-100β and NSE levels after off-pump versus on-pump coronary artery bypass graft surgery

Background

We aimed to evaluate serum levels of S-100 beta (S-100β) and neuron specific enolase (NSE) in patients with coronary heart disease (CHD) after off-pump versus on-pump coronary artery bypass graft (CABG) surgery.

Methods

The PubMed (~2013) and the Chinese Biomedical Database (CBM) (1982 ~ 2013) were searched without language restrictions. After extraction of relevant data from selected studies, meta-analyses were conducted using STATA software (Version 12.0, Stata Corporation, College Station, Texas USA). Possible sources of heterogeneity were examined through univariate and multivariate meta-regression analyses and verified by Monte Carlo Simulation.

Results

Eleven studies with a total of 411 CHD patients met the inclusion criteria. Our meta-analysis showed no significant difference in serum S-100β and NSE levels between the on-pump group and the off-pump group before surgery. In the on-pump group, there was a significant difference in serum S-100β levels of CHD patients between before and after surgery, especially within the first 24 h after surgery. Furthermore, in the on-pump group, there was a significant difference in serum NSE levels of CHD patients between before and after surgery, particularly at 0 h after surgery. In the off-pump group, there was an obvious difference in serum S-100β levels between before and after surgery, especially within 24 h after surgery. Our results also demonstrated that serum S-100β and NSE levels of CHD patients in the on-pump group were significantly higher than those of patients in the off-pump group, especially within 24 h after surgery.

Conclusions

Our findings provide empirical evidence that off-pump and on-pump CABG surgeries may increase serum S-100β and NSE levels in CHD patients, which was most prominent within 24 h after on-pump CABG surgery.

ISMICS Consensus Conference and Statements of Randomized Controlled Trials of Off-Pump versus Conventional Coronary Artery Bypass Surgery

Objective

At this consensus conference, we developed evidence-informed consensus statements and recommendations on the practice of off-pump coronary artery bypass graft (OPCAB) by systematically reviewing and performing meta-analysis of the randomized controlled trials (RCTs) comparing OPCAB and conventional coronary artery bypass (CCAB).

Methods

All RCTs of OPCAB versus CCAB through April 2013 were screened, and 102 relevant RCTs (19,101 patients) were included in a systematic review and meta-analysis (15 RCTs of 9551 high-risk patients; and 87 RCTs of 9550 low-risk patients) in accordance with the Cochrane Collaboration and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. Consensus statements for the risks and benefits of OPCAB surgery in mortality, morbidity, and resource use were developed based on best available evidence.

Results

Compared to CCAB, it is reasonable to perform OPCAB to reduce risks of stroke [class IIa, level of evidence (LOE) A], renal dysfunction/failure (class IIa, LOE A), blood transfusion (class I, LOE A), respiratory failure (class I, LOE A), atrial fibrillation (class I, LOE A), wound infection (class I, LOE A), ventilation time, and ICU and hospital length of stay (class I, LOE A). However, OPCAB may be associated with a reduced number of grafts performed (class I, LOE A) and with diminished graft patency (class IIa, LOE A, with increased coronary reintervention at 1 year and beyond (class IIa, LOE A), as well as increased mortality at a median follow-up of 5 years (class IIb, LOE A).

Conclusions

OPCAB compared with CCAB may improve outcomes in the short-term (stroke, renal dysfunction, blood transfusion, respiratory failure, atrial fibrillation, wound infection, ventilation time, and length of stay). However, over the longer-term, OPCAB may be associated with reduced graft patency, and increased risk of cardiac re-intervention and death.

Comparison of frequency of postoperative stroke in off-pump coronary artery bypass grafting versus on-pump coronary artery bypass grafting versus percutaneous coronary intervention

The stroke rate after coronary artery bypass grafting (CABG) compared to percutaneous coronary intervention (PCI) is generally considered high because cardiopulmonary bypass and aortic manipulations are often associated with cerebrovascular complications. However, an increasing number of CABGs performed without cardiopulmonary bypass (OPCAB) may improve those outcomes. Of 6,323 patients with multivessel and/or left main coronary artery disease, 3,877 patients underwent PCI, 1,381 conventional on-pump CABG, and 1,065 OPCAB. Median follow-up was 3.4 years. Stroke types were classified as early (onset of stroke within 24 hours after revascularization), delayed (within 30 days), and late (after 30 days). Propensity score analysis showed that the incidences of early, delayed, and late stroke did not differ between PCI and OPCAB (0.65, 95% confidence interval 0.08 to 5.45, p = 1.00; 0.36, 0.10 to 1.29, p = 0.23; 0.81, 0.52 to 1.27, p = 0.72, respectively). In contrast, incidence of early stroke after on-pump CABG was higher than after OPCAB (7.22, 1.67 to 31.3, p = 0.01), but incidences of delayed and late stroke were not different (1.66, 0.70 to 3.91, p = 0.50; 1.18, 0.83 to 1.69, p = 0.73). In conclusion, occurrence of stroke was not found to differ in patients after PCI versus OPCAB regardless of onset of stroke. Occurrence of early stroke after OPCAB was lower than that after on-pump CABG, yet occurrences of delayed and late strokes were similar for the 3 revascularization strategies.

Comparing S-100 beta protein levels and neurocognitive functions between patients undergoing on-pump and off-pump coronary artery bypass grafting

BACKGROUND

In the present study, we aimed to investigate the effects of off-pump coronary artery bypass grafting and on-pump cardiopulmonary bypass on the serum S-100 beta (S-100B) protein levels and neurocognitive functions of the patients.

MATERIALS AND METHODS

Sixty-four patients undergoing coronary artery bypass grafting (CABG) were enrolled in the study and were divided into two groups: off-pump (group I, n = 24) and on-pump CABG (group II, n = 40) group. Serum S-100B levels were measured before and 0, 6, and 24 h after the operation. Neurocognitive function tests were done preoperatively and were repeated in the postoperative period as well.

RESULTS

Serum S-100B levels were similar between the two groups preoperatively. However, median S-100B levels at 0, 6, and 24 h after the surgery were found to be significantly lower in the off-pump CABG group than in the on-pump group. The preoperative neurocognitive functions of the patients were similar between the two groups, whereas neurocognitive function was found to be significantly impaired postoperatively in the on-pump group in comparison with the off-pump CABG group.

CONCLUSION

We concluded that off-pump CABG is associated with decreased serum S100 protein levels and less impairment on neurocognitive functions compared with the on-pump group.

Haemodynamic changes during left anterior descending artery exposure in off-pump coronary artery bypass: comparison between use of moist laparotomy pads and deep pericardial traction sutures for heart displacement

Haemodynamic changes occurring during heart displacement, using moist laparotomy pads placed behind the heart (PAD group, n = 26) or deep pericardial traction sutures (DPS group, n = 25) to facilitate exposure of the left anterior descending artery during off-pump coronary artery bypass surgery, were compared. Haemodynamic variables were assessed before and 10 min after displacement of the heart. The central venous pressure, mean pulmonary artery pressure and pulmonary capillary wedge pressure increased in both groups. After heart displacement in the PAD group, the cardiac index, stroke volume index, mixed venous oxygen saturation, right ventricular ejection fraction and left ventricular stroke work index decreased significantly, and the systemic vascular resistance and pulmonary vascular resistance increased significantly; these parameters remained unchanged in the DPS group. It was concluded that displacement of the heart using moist laparotomy pads caused significant haemodynamic derangement compared with that caused by deep pericardial traction sutures.

Neurocognitive impairment after off-pump and on-pump coronary artery bypass graft surgery - an Iranian experience

BACKGROUND

Coronary artery bypass graft (CABG) surgery is one of the most commonly performed surgical procedures worldwide, and it may be accompanied by postoperative neurocognitive impairment. Although this complication has been attributed to the use of cardiopulmonary bypass, it is still a matter of debate whether the switch from on-pump to off-pump technique affects the cognitive function.

OBJECTIVE

The aim of this study was to compare the impact of the on-pump and off-pump techniques on neurocognitive impairment in low-risk CABG surgery groups.

METHODS

In a descriptive and analytic study, 201 CABG patients with left-ventricular ejection fraction >30%, and without cardiac arrhythmia were enrolled. Before the elective operation, all patients underwent neurological examination and neurocognitive test, Mini-Mental State Examination (MMSE). Two months following the operation, both on- and off-pump, the patients were re-examined by MMSE to detect any neurocognitive impairment.

RESULTS

Out of 154 patients included in the study, 95 (61.6%) and 59 (38.3%) patients were in off-pump and on-pump groups, respectively. Mean age of the patients was 57.17 ± 9.82 years. A 2-month postoperative neurocognitive impairment was detected among 17 patients of on-pump group (28.8%) and in 28 cases of off-pump group (29.4%) (P = 0.54). The mean postoperative MMSE scores were not comparable between groups (25.01 ± 4.49 in off-pump group versus 23.73 ± 4.88 in on-pump group, P = 0.09).

CONCLUSION

The present study revealed that in low-risk patients undergoing CABG surgery, either the techniques of on-pump or off-pump did not differ regarding the neurocognitive outcome 2 months after the procedure.

Correlation between cerebral tissue and central venous oxygen saturation during off-pump coronary bypass graft surgery

We compared simultaneous regional cerebral oxygen saturation and central venous oxygen saturation at different time periods in 20 adult patients (median age, 57.9; range, 35 to 76 years) undergoing off-pump coronary artery bypass (OPCAB) graft surgery (n= 20). Mean arterial pressure (MAP), partial pressure of carbon dioxide (PcvCO(2)), heart rate, haematocrit (Hct), lactate and patient oxygen saturation (SpO(2)) were also recorded as a secondary analysis to determine independent predictors of cerebral desaturation and interactions between predictors. The cross-sectional analysis performed at each time point showed several significant moderate to strong positive correlations between central venous oxygen saturation and both right and left cerebral oxygen saturations; however, right cerebral saturations correlated better with central venous saturations than left cerebral saturation. Partial pressure of carbon dioxide (PcvCO(2)) was identified as a major predictor of cerebral saturation 0.59 (p < 0.001). Central venous saturation can be used as a surrogate measure of cerebral oxygen saturation during OPCAB surgery.

Seizures after cardiac surgery

INTRODUCTION

Cardiac surgery, mainly in the form of coronary artery bypass graft surgery, is known to be associated with a risk of injury to the central and peripheral nervous systems. The most commonly encountered central nervous system injury associated with cardiac surgery continues to be stroke, with seizures occurring less commonly but with significant consequences. Seizures in the cardiac surgery recovery unit (CSRU) always cause great concern to the attending physicians and families of the patient. Therefore, it is of critical importance that the attending physician has an accurate and efficient approach to the differential diagnosis, investigations, and management of these patients, who represent a unique group requiring specific investigations and management.

METHODS

A review and discussion of experience with seizures in the CSRU.

DISCUSSION

Cardiac surgery poses a significant threat to the nervous system through various mechanisms although newer technologies and surgical techniques have led to improved outcomes in recent years. Although the incidence of seizures remains low, the causes and management are relatively unique in this setting, including a probable "toxic syndrome" related to certain antibiotics or other perioperative drugs such as tranexamic acid. A targeted approach based on recognizing focal versus generalized seizures, a careful review of history and medications, and a focused workup will lead the clinician to choosing the most effective therapy when one is required. Special concerns regarding the side effect profile of phenytoin in this setting have led to valproate and levetiracetam becoming useful alternatives, which are effective and well tolerated. The incidence of nonconvulsive seizures in the CSRU remains to be elucidated with prospective monitoring studies, as does their effect on outcome.

Size of left cardiac chambers correlates with cerebral microembolic load in open heart operations

Background. Microemboli are a widely recognized etiological factor of cerebral complications in cardiac surgery patients. The present study was aimed to determine if size of left cardiac chambers relates to cerebral microembolic load in open heart operations. Methods. Thirty patients participated in the study. Echocardiography was performed in 2-3 days before surgery. A transcranial Doppler system was used for registering intraoperative microemboli. Results. Preoperative left atrium and left ventricular end-systolic and end-diastolic sizes significantly correlated with intraoperative microembolic load (rs = 0.48, 0.57 and 0.53, Ps < .01, resp.). The associations between left ventricular diameters and number of cerebral microemboli remained significant when cardiopulmonary bypass time was included as a covariate into the analysis. Conclusions. The present results demonstrate that increased size of left heart chambers is an influential risk factor for elevated cerebral microembolic load during open heart operations. Mini-invasive surgery and carbon dioxide insufflation into wound cavity may be considered as neuroprotective approaches in patients with high risk of cerebral microembolism.

Microemboli are not associated with delirium after coronary artery bypass graft surgery

Delirium is an acute change in cognition which occurs frequently after coronary artery bypass graft (CABG) surgery. Cerebral microemboli, from plaque, air, or thrombus, have been hypothesized to contribute to delirium and cognitive decline after CABG. The purpose of this study was to determine if there was an association between cerebral microemboli and delirium after cardiac surgery. Non-delirious patients (n=68) were prospectively enrolled and underwent intraoperative monitoring of the middle cerebral arteries with transcranial Doppler (TCD). TCD signals were saved and analyzed postoperatively for microemboli manually, according to established criteria. Postoperatively, patients were assessed for delirium with a standardized battery. Thirty-three patients (48.5%) developed delirium after surgery. Microemboli counts (mean + or - SD) were not significantly different in those with and without delirium (303 + or - 449 vs. 299 + or - 350; p=0.97). While intraoperative microemboli were not associated with delirium after CABG, further investigation into the source and composition of microemboli can further elucidate the long-term clinical impact of microemboli.

Temporal pattern of strokes after on-pump and off-pump coronary artery bypass graft surgery

BACKGROUND

The incidence of strokes has not decreased after coronary artery bypass graft surgery (CABG). The purpose of this study is to identify incidence, risk factors, and temporal pattern of strokes after on-pump and off-pump CABG.

METHODS

We analyzed 2,516 consecutive patients who underwent first elective isolated CABG. The primary endpoint was strokes within 30 days. The temporal onset of the deficits was classified by consensus as either an "early stroke," which is present just after emergence from anesthesia, or a "delayed stroke," which is present after first awaking from surgery without a neurologic deficit.

RESULTS

More than half of strokes (29 of 46; 63%) were delayed strokes. Patients undergoing off-pump CABG had significantly lower risk of early stroke (0.1% versus 1.1%, p = 0.0009), whereas the incidence of delayed strokes was not different significantly (0.9% versus 1.4%, p = 0.3484) between patients undergoing on-pump and off-pump CABG. In multivariate analyses, undergoing off-pump CABG was an independent protective factor for all strokes (relative risk 0.29, 95% confidence interval: 0.14 to 0.56, p = 0.0005) and early strokes (relative risk 0.05, 95% confidence interval: 0.003 to 0.24, p < 0.0001), but it was not an independent protective factor for delayed strokes (relative risk 0.54, 95% confidence interval: 0.24 to 1.17, p = 0.1210).

CONCLUSIONS

Undergoing off-pump CABG reduces the incidence of perioperative stroke mainly by minimizing early strokes; however, the risk of delayed strokes is not different between patients undergoing on-pump and off-pump CABG.

A multimodal approach to the prevention of postoperative stroke in patients undergoing coronary artery bypass surgery

BACKGROUND

Stroke is known to be multifactorial in origin. This study was designed to assess the effectiveness of a multimodal approach to preventing this complication in patients undergoing coronary artery bypass.

METHODS

One thousand five hundred thirty consecutive coronary artery bypass patients operated on by a single surgeon from July 1994 to April 2008 were studied. Group 1 patients (n = 1,214) were operated on before 2004. Group 2 patients (n = 316) were operated on after 2004. In group 2 patients, epiaortic scanning, selective use of proximal anastomotic devices, and alternative cannulation were used. Off-pump coronary artery bypass (OPCAB) was used in 730 patients. On-pump coronary artery bypass (ONCAB) was used in 800 patients. Preoperative risk factors including age, cerebrovascular disease, peripheral vascular disease, hypertension, and diabetes were examined in all patients. The incidence of postoperative stroke was determined for group 1 and 2 patients and the individual cohorts of OPCAB and ONCAB patients.

RESULTS

The overall incidence of stroke was 1.6% (25/1,530). The postoperative incidence of stroke was 1.7% (21/1,214) in group 1 patients as compared with 1.3% (4/316) in group 2 patients. The incidence of postoperative stroke was 2.4% (19/800) in ONCAB patients as compared with 0.8% (6/730) in OPCAB patients (P < .05).

CONCLUSIONS

OPCAB is an important tool for the prevention of postoperative stroke. Adjunctive techniques for the prevention of emboli from the ascending aorta may also reduce the risk of stroke in OPCAB and ONCAB patients.

Intraoperative cerebral high-intensity transient signals and postoperative cognitive function: a systematic review

BACKGROUND

Much attention in the literature has focused on the relationship between perioperative microemboli during cardiac and vascular surgery and postoperative cognitive decline. Transcranial Doppler ultrasonography (TCD) has been used to measure high-intensity transient signals (HITS), which represent microemboli during cardiac, vascular, and orthopedic surgery. The purpose of this study was to systematically examine the literature with respect to HITS and postoperative cognitive function.

METHODS

Systematic PubMed searches identified articles related to the use of TCD and cognitive function in the surgical setting.

RESULTS

The literature remains largely undecided on the role of HITS and cognitive impairment after surgery, with most studies being underpowered to show a relationship. Although the cognitive effects of HITS may be difficult to detect, subclinical microemboli present potential harm, which may be modifiable.

CONCLUSIONS

TCD represents a tool for intraoperative cerebral monitoring to reduce the number of HITS during surgery.

Current Status of Off-Pump Coronary Artery Bypass Surgery

The expanding indications for angioplasty coupled with the successful short and mid-term results of randomized controlled trials of drug-eluting stents have already had an unquestionable impact on the practice of coronary revascularization operations. However, coronary artery bypass grafting remains a major mode of therapy for coronary artery disease. It is likely that surgery will continue to be preferred for more complex subsets and that surgeons will have to continue to maintain good results in patients with more complex problems. Concerns regarding morbidity associated with conventional surgical myocardial revascularization on cardiopulmonary bypass have led to a resurgence of interest in off-pump bypass surgery during the last decade, with the expectation that it would be safer if cardiopulmonary bypass could be avoided. This review summarizes the impact of off-pump bypass surgery in reducing the morbidity and mortality associated with conventional coronary artery bypass on cardiopulmonary bypass by evaluating the current best-available evidence from randomized controlled trials and meta-analyses comparing off-pump surgery with conventional bypass grafting.

The influence of epiaortic ultrasonography on intraoperative surgical management in 6051 cardiac surgical patients

BACKGROUND

Intraoperative echocardiography has become a mainstay monitor of cardiac function and a popular diagnostic tool in patients undergoing cardiac procedures. Previous reports suggest that epiaortic ultrasonography (EU) is superior to transesophageal echocardiography and manual palpation in identifying ascending aortic atheroma. Its impact on surgical decision making has not been thoroughly investigated, however.

METHODS

We retrospectively analyzed the medical records of 6051 consecutive patients who underwent EU of their ascending aorta during cardiac operations between 1996 and 2006 to determine a potential impact on intraoperative surgical decision making. Aortic atheroma was graded according to standard classification. Neurologic complications were evaluated according to the Society of Thoracic Surgeon definition for stroke and transient ischemic attack (TIA).

RESULTS

The overall impact of EU on surgical decision making was 4.1% and included a change in the technique for inducing cardiac arrest in 1.8%, aortic atherectomy or replacement surgery in 0.8%, requirement for off-pump coronary artery bypass grafting (CABG) in 0.6%, avoidance of aortic cross-clamping and use of ventricular fibrillatory arrest in 0.5%, change in arterial cannulation site in 0.2%, or avoidance of aortic cannulation in 0.2%. The greatest affect of EU was observed in patients undergoing combined CABG with aortic/mitral valve procedures (6.7%). The smallest impact was seen in patients undergoing mitral valve operations (1.4%). Aortic atheroma was more frequent on the anterior aspect of the aorta (n = 171) in patients with a change in surgical plan than on the posterior aspect (n = 78). The overall stroke rate was lower in patients with intraoperative EU compared with all patients undergoing surgical procedures.

CONCLUSIONS

Epiaortic ultrasonography is a useful technique to detect ascending aortic atheroma, has a significant impact on surgical decision making in more than 4% of cardiac surgical patients, and might result in improved perioperative neurologic outcome.

Occurrence and clinical impact of microembolic signals during or after cardiosurgical procedures

BACKGROUND AND PURPOSE

Microembolic signals (MESs) are detectable within the transcranial Doppler frequency spectrum downstream from vascular atherothrombotic or cardiothrombotic lesions. A frequent occurrence of MESs has also been shown during bypass surgery or after mechanical valve implantation. We sought to compile the knowledge on MES prevalence, the clinical impact of these cardiogenic MESs, and microemboli composition.

SUMMARY OF REVIEW

We performed a systematic MEDLINE search and summarized the currently available literature about MESs during or after cardiosurgical procedures for this state-of-the-art report.

CONCLUSIONS

The nature of cardiogenic MESs is heterogeneous, and their prevalence is highly variable, reflecting their different origin from a broad spectrum of cardiosurgical conditions. The occurrence and number of MESs during cardiac catheterization and percutaneous coronary angioplasty seem to have a clinical impact but need to be explored further. In patients with prosthetic heart valves, in those with left ventricular assist devices, and during cardiac surgery, the occurrence of MESs has an important clinical impact, and MES monitoring has proven its reliability. Although the data encourage intensifying MES detection in cardiac disorders, their heterogeneous nature does not yet allow the use of MESs as a general surrogate parameter for neuronal damage or cardial thromboembolic risk.

Neurocognitive function and cerebral emboli: randomized study of on-pump versus off-pump coronary artery bypass surgery

BACKGROUND

Neurocognitive impairment can be a debilitating complication after coronary artery bypass graft surgery (CABG). Cardiopulmonary bypass, in particular, cerebral emboli, has been implicated. We compared neurocognitive function and cerebral emboli in patients undergoing on-pump and off-pump CABG.

METHODS

212 patients admitted for CABG were randomly assigned to on-pump (n = 104) or off-pump (n = 108) surgery. Embolic signals were detected with bilateral transcranial Doppler ultrasonography of the middle cerebral artery. Neurocognitive tests were administered preoperatively, on discharge from hospital, at 6 weeks, and at 6 months after surgery. Composite neurocognitive scores were derived using principal component analysis and were compared between the two groups, using analysis of covariance to adjust for baseline values.

RESULTS

At discharge from hospital, the adjusted composite neurocognitive score was 0.25 standard deviations greater in the off-pump group compared with the on-pump group (95% confidence interval: 0.05 to 0.45; p = 0.01). There was no significant difference at 6 weeks (0.09 standard deviations, 95% confidence interval: -0.11 to +0.30; p = 0.4) and 6 months (-0.002 standard deviations, 95% confidence interval: -0.23 to +0.23; p = 1.0). Median number of embolic signals was 1,605 (751 to 2,473) during on-pump and 9 (4 to 27) in off-pump CABG (p < 0.001). Age, length of education, and on-pump status were independent predictors of the predischarge neurocognitive score (p = 0.02, 0.03, and 0.006, respectively).

CONCLUSIONS

Cerebral emboli are more prevalent during on-pump CABG. At discharge from hospital, neurocognitive function is better after off-pump surgery, possibly as a result of the lower embolic load. However, the difference in neurocognitive function does not persist at 6 weeks and 6 months.

Revascularization with off-pump coronary artery surgery: what appears new is actually the old rediscovered

The enormous progress in interventional cardiology during the last 10 years has resulted in a major change in the spectrum of patients referred for coronary artery bypass grafting. Several large retrospective analyses, meta-analyses, and the randomized trials that addressed different aspects of ONCAB and OPCAB to date have compared the two surgical strategies. It is suggested that patients may achieve an excellent outcome with either type of procedure, and individuals' outcomes more likely depend on factors other than whether they underwent ONCAB or OPCAB. Nevertheless, there appear to be trends in most studies. These trends include less blood loss and need for transfusion, less myocardial enzyme release up to 24 h, less early neurocognitive dysfunction, and less renal insufficiency after OPCAB and propensity to lower costs, thereafter proving OPCAB to be safe and clinically effective. Here, we review the physiological advantages and clinical outcomes of OPCAB for myocardial revascularization and examine whether either strategy is superior and in which patients.

Prevention of Ischemic Neurologic Injury With Intraoperative Monitoring of Selected Cardiovascular and Cerebrovascular Procedures: Roles of Electroencephalography, Somatosensory Evoked Potentials, Transcranial Doppler, and Near-Infrared Spectroscopy

All neuromonitoring techniques, although imperfect, provide useful information for monitoring cardiothoracic and carotid vascular operations. They may be viewed as providing complementary information, which may help surgical technique and, as a result, possibly improve clinical outcomes. As of this writing, the efficacy of TCD and NIRS monitoring during cardiothoracic and vascular surgery cannot be considered established. Well designed, prospective, adequately powered, double-blind, and randomized outcome studies are needed to determine the optimal neurologic monitoring modality (or modalities), in specific surgical settings.

Is single or double aortic clamping safer in terms of cerebral outcome during coronary bypass surgery?

The purpose of the present study was to investigate retrospectively which aortic clamping technique, the single clamp technique (SCT) or double clamping technique (DCT), is safer in terms of cerebral functions in patients who have undergone coronary bypass surgery. We evaluated 1100 patients who underwent coronary artery bypass graft surgery at our institute from 1998 to 2004. The two groups, SCT (n = 550, 50%) and DCT (n = 550, 50%), were comparable with respect to smoking, hypertension, hypercholesterolemia, diabetes mellitus, chronic obstructive pulmonary disease, peripheral arterial disease, history of neurological events, creatinine levels, and existence of a carotid lesion. No significant differences between the SCT and DCT groups were observed in terms of cardiac and cerebral complications perioperatively and postoperatively. Both single and double clamping techniques have advantages and disadvantages in patients undergoing coronary bypass surgery.

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.

Cognitive and neurobehavioral dysfunction after cardiac bypass procedures

From a cognitive standpoint, CABG as currently practiced appears to be safe for the great majority of patients, but transient changes involving memory, executive functions, and motor speed may still occur in a subset of patients during the first few days to weeks after CABG. The etiology most likely is multifactorial and includes a synergistic effect of microemboli, hypo-perfusion, and other variables associated with major surgery. Older age and degree of pre-existing cerebrovascular disease have been identified as important risk factors. The short-term cognitive changes appear to be reversible by 3 months after surgery for most patients. Late cognitive decline after CABG,occurring between 1 and 5 years after the surgery, has been well documented,but controlled studies demonstrating that this decline is specifically attributable to the use of cardiopulmonary bypass itself rather than to progression of underlying cerebrovascular disease or other age-related changes are pending.

Cerebral microembolization during off-pump coronary artery bypass surgery with the Symmetry aortic connector device

OBJECTIVE

The use of aortic connector systems for proximal vein grafts in off-pump coronary artery bypass grafting might minimize aortic manipulation by eliminating the need for partial aortic clamping. The objective of this study was to asses whether use of a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) reduced intraoperative cerebral embolization.

METHODS

Thirty-two consecutive patients underwent off-pump coronary artery bypass grafting. Sixteen patients received at least one mechanical proximal vein graft anastomosis with a Symmetry aortic connector system. Sixteen patients representing the control group underwent operations with standard suturing techniques using partial aortic clamping. During surgical intervention, all patients were monitored continuously with multifrequency transcranial Doppler scanning, which detected and differentiated cerebral emboli.

RESULTS

There were significantly more cerebral emboli in the Symmetry group (median, 36) compared with the control group (median, 11; P = .027). This was due to a higher number of gaseous emboli in the Symmetry group than in the control group (median, 27 vs 8; P = .014), whereas there was no significant difference regarding the number of solid emboli (median, 7 vs 3; P = .139).

CONCLUSION

Use of a Symmetry connector system during proximal vein graft anastomosis increased the number of emboli to the brain compared with a standard technique in coronary bypass surgery without cardiopulmonary bypass.

Early neurocognitive function of patients after off-pump coronary artery bypass surgery

DESIGN

This was a prospective, descriptive study.

SETTING

The study took place in cardiovascular units at a large urban metropolitan, midwestern tertiary care hospital.

SAMPLE

Fifty-four patients undergoing off-pump coronary artery bypass surgery were included.

OUTCOME MEASURES

Outcome measures were neurocognition preoperatively at baseline (within 72 hours of surgery) and postoperatively (at least 72 hours after surgery but before discharge).

RESULTS

In neurocognitive tests of cognition (memory, language, and attention) there was an improvement in the cognitive composite from the preoperative baseline to the postoperative follow-up (P < .001). However, in tests of motor function (motor speed and information processing speed) there was a decline in the motor composite (P = .006).

CONCLUSIONS

After off-pump coronary artery bypass surgery, patients had an overall improvement in tests of memory, language, and attention (cognitive composite), but a decline in tests of motor speed and information processing speed (motor composite).

Relation between neurocognitive impairment, embolic load, and cerebrovascular reactivity following on- and off-pump coronary artery bypass grafting

OBJECTIVES

To evaluate the effect of on-pump and off-pump coronary artery bypass grafting (CABG) on postoperative cognitive impairment and cerebrovascular reactivity, with attention for the perioperative high-intensity transient signals (HITS).

DESIGN

A prospective comparative study.

SETTING

Urban university hospital.

PATIENTS

Candidates for cardiac surgery.

METHODS

Measurement of HITS as a reflection of embolic load was performed in 50 patients (on-pump CABG, n = 32; off-pump CABG, n = 18). To measure cognitively induced cerebrovascular reactivity, cerebral blood flow velocity (BFV) was measured preoperatively in 66 patients, early postoperatively (after 6 days) in 63 patients, and late postoperatively (after 6 months) in 44 patients during five cognitive tasks. In the same session, seven standardized neuropsychological tests were administered.

RESULTS

A higher embolic load was found in the on-pump group (p < 0.01). In the on-pump group, aortic cannulation was the most important HITS-prone surgical maneuver. Repeated-measures multivariate analysis of variance (using surgical technique as between-subjects factor and significant differences between both groups as covariates) on the group data revealed no significant differences in neuropsychological performance and BFV immediately after surgery or at 6 months after surgery, compared with preoperative performance. No main effect of surgery was found for neuropsychological performance and BFV. No significant correlations were found between the number of HITS and the degree of postoperative neuropsychological impairment. Individual comparisons revealed that 60% (59.4% in the on-pump group; 61.1% in the off-pump group) of the patients undergoing CABG showed evidence of cognitive impairment soon after surgery. In 24.2%, the cognitive sequelae persisted at 6 months follow-up (31.8% in the on-pump group; 9.1% in the off-pump group). The cognitive impairment index (sum of impaired neuropsychological tests) showed a significant difference after 6 months between both surgery groups with fewer neurocognitive tests that remained impaired in the off-pump group.

CONCLUSIONS

In off-pump surgery, significantly fewer HITS were observed. On an individual level, more favorable results in neuropsychological test performance were demonstrated in the off-pump group after 6 months. The number of HITS showed no correlation with degrees of early and late postoperative neuropsychological impairment.

Jugular bulb desaturation during coronary artery surgery: a comparison of off-pump and on-pump procedures † †Presented in part at the annual Outcomes Meeting at Key West, FL, USA, 2001. ‡ ‡This article is accompanied by the Editorial

BACKGROUND

Conventional coronary artery bypass surgery has been associated with cerebral injury attributed to cardiopulmonary bypass (CPB) and surgical manipulation of the ascending aorta. Off-pump coronary artery surgery avoids these factors and could prevent cerebral injury. However, moving the heart from its natural position affects the circulation and could compromise cerebral oxygenation and perfusion. We set out to compare episodes of poor global cerebral oxygenation, defined as a jugular bulb saturation less than 50%, between patients randomized to off-pump or (conventional) on-pump coronary artery surgery.

METHODS

One hundred and eighty-seven patients were assigned randomly to off-pump or on-pump coronary artery surgery. Oxygen saturation in the jugular bulb (SjO2) was measured during revascularization of the three main coronary vessels in the off-pump group, and at the start of CPB, before rewarming, and after rewarming in the on-pump group. We compared samples with jugular bulb with desaturation (SjO2) < or = 50%) between treatment groups.

RESULTS

One hundred and seventy-five patients (81 in the off-pump group [93%] and 94 in the on-pump group [94%]) had complete jugular oxygen saturation data. Thirty-nine patients in the off-pump group (48%) and 25 patients in the on-pump group (27%) had one or more samples with desaturation during revascularization or CPB (odds ratio after adjustment for other factors, 0.39; 95% confidence interval, 0.21-0.73, P<0.01).

CONCLUSION

Jugular bulb desaturation occurs more frequently during off-pump coronary artery surgery than during conventional coronary artery surgery.