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

Use of intraoperative epiaortic ultrasonography to delineate aortic atheroma

OBJECTIVE

A cerebrovascular accident (CVA) is a devastating complication of coronary artery bypass grafting (CABG) and a major cause for morbidity and mortality. Aortic manipulation, cannulation, and clamping during CABG may lead to release of atheromatous material from the ascending aorta, which may cause a CVA. This study assessed the hypothesis that the use of intraoperative epiaortic ultrasonography (EAUS) would supplement imaging information with that derived from manual aortic palpation and influence the surgical decision-making approach accordingly.

METHODS

After undergoing a mid-sternotomy for CABG, 105 patients underwent EAUS with an 8-MHz transducer ordinarily used for conventional transthoracic echocardiography. The surgical strategy was decided on at three stages: preoperatively, after manual aortic palpation, and following EAUS.

RESULTS

The preoperative strategy had assigned 105 patients to the "touched aorta" group that was planned for either on-pump or off-pump CABG (OPCAB) with proximal anastomosis to the aorta. Pathologic lesions of the atheromatotic ascending aorta were evident in 40 patients (38%), with the lesions detected in 22 patients (21%) by both palpation and EAUS, and in 18 patients (17%) by EAUS alone. The planned surgical strategy was changed in 29 patients (28%): 25 patients (24%) were converted from on-pump CABG to OPCAB, and the EAUS influenced the choice of the aortic cannulation, cross-clamping, and proximal anastomosis site in 4 patients (4%). Among the changes in surgical decision making, changes in 11 patients (10%) were based on lesion detection by both manual palpation and EAUS; in 18 patients (17%), changes resulted from pathologic evidence provided by EAUS alone.

CONCLUSIONS

This study showed EAUS to be more sensitive in detecting atherosclerotic lesions than manual intraoperative palpation of the ascending aorta. This investigation contributes new data on the effect of EAUS on intraoperative surgical approach in the era of OPCAB. The use of EAUS has emerged as an important tool in intraoperative decision making, and we recommend its use routinely in CABG procedures.

Neurocognitive complications after coronary artery bypass surgery

Both short- and long-term cognitive changes continue to occur after coronary artery bypass grafting (CABG), but the pathophysiology of these neurobehavioral changes remains incompletely understood. The persistence of mild postoperative neurocognitive changes despite multiple improvements in the cardiopulmonary bypass procedure may be partially because of surgical populations being older and having more prevalent comorbid disease. The cause of the early postoperative changes is most likely multifactorial and may include ischemic injury from microemboli, hypoperfusion, and other factors resulting from major surgery. Several lines of evidence suggest that the late cognitive decline between 1 and 5 years after surgery may be secondary to high rates of cerebrovascular disease among candidates for CABG. A history of hypertension and other risk factors for vascular disease is known to be associated with increased risk for long-term cognitive decline in community-dwelling elderly individuals. Cerebrovascular risk factors are also associated with silent magnetic resonance imaging abnormalities in patients undergoing CABG. Thus, whereas both short- and long-term postoperative cognitive changes have been associated with CABG, only the short-term, transient changes appear to be directly related to the use of cardiopulmonary bypass.

The Influence of Type 2 Diabetes Mellitus in Patients Undergoing Coronary Artery Bypass Graft Surgery

OBJECTIVE

To prospectively assess whether there are any outcome differences between patients with and without type 2 diabetes mellitus undergoing coronary artery bypass graft (CABG) surgery.

STUDY DESIGN

This was an 8-year, prospective hospitalization cohort study. Data were collected on 225 variables concurrently with hospital admission. The main outcome was total operative mortality. In addition, we evaluated 12 morbidity outcomes. To minimize confounding, we controlled for 16 other variables.

RESULTS

A total of 6,711 patients were available for our analysis (diabetic patients, 2,178; and nondiabetic patients, 4,533). The diabetic patients were significantly more likely to be women, to have more left ventricular hypertrophy, to have a history of cerebrovascular disease, hypertension, and COPD, to have a greater body surface area, to have higher creatinine levels, to be African-American, to have undergone more elective procedures, to have a shorter pump time, and to have less of a history of tobacco use compared to nondiabetic patients (p < 0.05). Multiple regression analysis found no significant difference between the two groups for all 12 morbidity outcomes of interest. Diabetic patients experienced significantly more mortality than nondiabetic patients (relative risk, 1.67; 95% confidence interval, 1.20 to 2.30; p < 0.004).

CONCLUSION

Patients with type 2 diabetes who are undergoing CABG surgery experience significantly more total operative mortality compared to nondiabetic patients, even after controlling for multiple variables. There was no difference between the groups for 12 morbidity outcomes.

Selective Use of Off-Pump Coronary Bypass Surgery Reduces Mortality and Neurologic Morbidity Associated with High-Risk Coronary Bypass Surgery: A 400-Case Comparative Experience

The frequency of use of off-pump coronary artery bypass (CAB) surgery to surgically treat coronary artery disease has varied greatly from center to center and from surgeon to surgeon because of preference, training, and experience. We report an experience with 400 consecutive isolated CAB procedures selectively managed with on-pump or off-pump surgery, according to the perceived potential for aortic embolization or stroke as determined by clinical and imaging determinations. The off-pump CAB group (46 patients) was 7.1 years older (P < .05) and had an 11% lower ejection fraction (P < .03) than the on-pump group. There was no difference in gender, urgency of surgery, hemodynamic stability, angina class, or incidence of prior myocardial infarction. All 400 patients underwent intraoperative transesophageal echocardiography, and many underwent an epiaortic study to supplement image quality. Patients without palpable or imaged advanced aortic disease or deemed to be at clinically high risk for stroke (advanced age, prior strokes, or advanced cerebrovascular or peripheral vascular disease) underwent on-pump procedures requiring 55 minutes of aortic ischemia and 97 minutes of high-flow, high-pressure bypass on average. All others underwent off-pump procedures. The numbers of grafts per patient were similar (3.2 on-pump, 2.8 off-pump; = ns). There was no in-hospital or 30-day mortality in either group. Using the New York State risk-adjustment algorithm, we found the predicted mortality rate for the off-pump group was higher (2.24% on-pump versus 5.54% off-pump, P = .008). The postoperative length of stay was longer in the off-bypass group (3.67 days versus 4.31 days, P = .003). The frequencies of hospital readmission and perioperative complications (renal, pulmonary, infection, bleeding, cardiac, neurologic) were similar, and there were no postoperative strokes in either group. The selective use of off-pump surgery safely managed patients at higher risk for perioperative stroke and associated embolic multisystem organ failure and death. Individual surgeon and center-wide use of a selective approach is recommended as an alternative to a single-procedure nonselective approaches.

The Impact of Aortic Manipulation on Neurologic Outcomes After Coronary Artery Bypass Surgery: A Risk-Adjusted Study

BACKGROUND

Cerebral embolization of atherosclerotic plaque debris caused by aortic manipulation during conventional coronary artery bypass grafting (CABG) is a major mechanism of postoperative cerebrovascular accidents (CVA). Off-pump CABG (OPCABG) reduces stroke rates by minimizing aortic manipulation. Consequently, the effect of different levels of aortic manipulation on neurologic outcomes after CABG surgery was examined.

METHODS

From January 1998 to June 2002, 7,272 patients underwent isolated CABG surgery through three levels of aortic manipulation: full plus tangential (side-biting) aortic clamp application (on-pump surgery; n = 4,269), only tangential aortic clamp application (OPCABG surgery; n = 2,527) or an "aortic no-touch" technique (OPCABG surgery; n = 476). A risk-adjusted logistic regression analysis was performed to establish the likelihood of postoperative stroke with each technique. Preoperative risk factors for stroke from the literature, and those found significant in a univariable model were used.

RESULTS

A significant association for postoperative stroke correspondingly increasing with the extent of aortic manipulation was demonstrated by the univariable analysis (CVA incidence respectively increasing from 0.8% to 1.6% to a maximum of 2.2%, p < 0.01). In the logistic regression model, patients who had a full and a tangential aortic clamp applied were 1.8 times more likely to have a stroke versus those without any aortic manipulation (95% confidence interval: 1.15 to 2.74, p < 0.01) and 1.7 times more likely to develop a postoperative stroke than those with only a tangential aortic clamp applied (95% confidence interval: 1.11 to 2.48, p < 0.01).

CONCLUSIONS

Aortic manipulation during CABG is a contributing mechanism for postoperative stroke. The incidence of postoperative stroke increases with increased levels of aortic manipulation.

Total Arterial Off-Pump versus On-Pump Coronary Revascularization:. Comparison of Early Outcome

BACKGROUND AND AIM

To assess differences in the early outcome after complete arterial myocardial revascularization with (ONCAB) or without cardiopulmonary bypass (OPCAB).

METHODS

Out of 870 consecutive CABG procedures 58 OPCAB and 91 ONCAB patients receiving exclusive arterial grafts were analyzed. OPCAB patients had more single-vessel (p < 0.0001), less triple-vessel (p < 0.0001) or left main disease (p = 0.0021), higher angina class (p = 0.003), unstable angina (p < 0.0001) or previous PTCAs (p < 0.0001).

RESULTS

ONCAB was associated with longer operations (182.5 +/- 38 vs. 147 +/- 56 min; p = 0.0001) and more anastomoses/patient (3.2 +/- 1 vs. 2 +/- 0.9; p < 0.0001), but incomplete revascularization was similar in both groups (11% vs. 17%; p = ns). ITA use was identical, whereas single left internal thoracic artery (LITA) use (25.9% vs.1%; p < 0.0001) and LITA jump anastomoses (10.3% vs. 7.7%; p < 0.0001) were more frequent in OPCAB. Radial artery (RA) use (89% vs. 46.6%; p < 0.0001) and RA jump anastomoses (57.1% vs. 12.1%; p < 0.0001) were more frequent in ONCAB. Mortality, arrhythmias, cerebro-vascular accidents (CVA), and renal failure were similar, but ventilatory support shorter (8.8 +/- 11.8 vs. 15.6 +/- 9.4 h; p < 0.0001) and cardiac enzyme release smaller (p < 0.0001) after OPCAB with a trend toward less myocardial infarction (1.7% vs. 7.7%; p = 0.12) and low output (1.7% vs. 8.8%; p = 0.089), and more respiratory complications (10.3% vs. 2.2%; p = 0.056).

CONCLUSIONS

Arterial OPCAB patients have less extensive CAD, but more severe symptoms. Early outcome is similar concerning mortality, arrhythmias, CVA, renal failure, or ICU and hospital stay, but with shorter ventilatory support and lower cardiac enzymes with a trend toward lower myocardial infarction and low output, but higher respiratory complication rates after OPCAB.

Side Effects of Cardiopulmonary Bypass:. What Is the Reality?

Despite many years of clinical and experimental research, the contribution of cardiopulmonary bypass (CPB) and cardioplegic arrest to morbidity and mortality following cardiac surgery remains unclear. This is due, in part, to lack of suitable control group against which bypass and cardioplegic arrest can be compared. The recent success of beating heart coronary artery bypass grafting has, however, for the first time, provided an opportunity to compare the same operation, in similar patient groups, with, or without CPB and cardioplegic arrest. CPB is associated with an acute phase reaction of protease cascades, leucocyte, and platelet activation that result in tissue injury. This is largely manifest as subclinical organ dysfunction that produces a clinical effect in those patients that generate an excessive inflammatory response or in those with limited functional reserve. The contribution of myocardial ischemia/reperfusion, secondary to aortic cross-clamping, and cardioplegic arrest, to the systemic inflammatory response and wider organ dysfunction is unknown, and requires further evaluation in clinical trials.

On-Pump Versus Off-Pump Coronary Artery Bypass Grafting in Diabetic Patients: A Propensity Score Analysis

BACKGROUND

Diabetic patients are recognized as being at high risk for adverse outcomes after coronary artery bypass grafting. We evaluated our outcomes in diabetic patients to compare the effect of off-pump with on-pump coronary revascularization.

METHODS

Between April 1997 and September 2002, 951 consecutive diabetic patients underwent isolated coronary artery bypass grafting. A total of 186 (19.6%) of these patients had off-pump coronary procedures. Multivariate logistic regression was used to assess the effect of off-pump coronary procedures on adverse in-hospital outcomes, while adjusting for patient and disease characteristics by constructing a propensity score from core patient characteristics. The propensity score was the probability of receiving off-pump coronary operation, with a C-statistic of 0.81, and was included along with the comparison variable in a multivariable analysis of outcome. All analysis was performed retrospectively.

RESULTS

Off-pump patients were more likely to be obese (p = 0.032), have left main stem stenosis (p = 0.034), and have undergone prior cardiac operation (p = 0.027). The off-pump group had fewer patients with three-vessel disease compared with the on-pump group. After risk adjusting with propensity score, off-pump patients had a significantly lower incidence of stroke (adjusted odds ratio 0.15; p = 0.039) and renal failure (adjusted odds ratio 0.38; p = 0.036). Off-pump patients also required less blood transfusion (p < 0.001) and had shorter lengths of stay (p < 0.001).

CONCLUSIONS

Off-pump coronary operation in diabetic patients significantly reduced postoperative morbidity and length of stay compared with on-pump coronary operation, although no in-hospital survival difference was noted between the two groups.

Predictors of stroke in patients undergoing coronary artery bypass grafting surgery: A prospective, nested, case-control study

The objective of the present study was to assess the risk factors for stroke in patients undergoing coronary artery bypass grafting (CABG) surgery. We conducted a nested case-control study from a 9-year, prospective hospitalization cohort (n = 6245). Inclusion in the cohort included CABG between October 1993 and June 2002. Exclusion criteria included any other simultaneously performed surgery. Cases were defined as patients who underwent CABG and experienced a stroke (171 cases, 2.7% of the total), and controls were patients who underwent CABG without a stroke. Cases were matched to controls at a ratio of 1:3 (513 controls). The 39 predictor variables were pump time, body surface area, creatinine, previous percutaneous transcoronary angioplasty (PTCA), clamp time, coronary perfusion time, previous cardiac surgeries, hypertension, race, sex, previous myocardial infarction, family history of coronary disease, history of cerebrovascular disease, preoperative neurologic disease, pulmonary hypertension, aortic disease, previous intervention within 30 days, angina history, bleeding history, previous vascular surgery, diabetes, age, myocardial findings, chronic obstructive pulmonary disease, New York Heart Association class, previous gastrointestinal disease, current vascular disease, systemic diseases, vessels at last PTCA, PTCA result, current smoking, tobacco history, dialysis, current anticoagulant therapy, character of operation, left ventricular hypertrophy, hypercholesterolemia, and chronic corticosteroid therapy. There were 13 significant predictors of stroke. Regression analysis revealed 3 independent predictors of stroke: age >70 years (odds ratio [OR], 4.61; 95% confidence interval [CI], 2.84-6.07), poor preoperative neurologic status (OR, 4.24; 95% CI, 2.02-5.79), and previous cardiac surgery (OR, 1.75; 95% CI, 1.05-2.91). We conclude that in patients undergoing CABG surgery, the independent predictors for stroke, in order of risk, are age >70 years, poor preoperative neurologic status, and previous cardiac surgery.

Off-pump versus on-pump coronary artery bypass surgery: does the pump influence outcome?1 1No competing interests declared

BACKGROUND

This study assessed hospitalization outcome differences for patients undergoing off-pump coronary artery bypass (OPCAB) grafting compared with patients having coronary artery bypass grafting with cardiopulmonary bypass.

STUDY DESIGN

We conducted a nested case-control study from an 8-year, hospitalization cohort (n = 7,905) in which the data were collected prospectively. Inclusion criteria included a coronary artery bypass graft only and age greater than 18 years. Cases were patients undergoing OPCAB (n = 360) and controls were patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (n = 1,080). Cases were matched to controls 1:3 on five variables: age (+/- 3 years), gender, diabetes, New York Heart Association Functional Classification, and surgical year (+/- 3 years). The 13 outcomes of interest were mortality, length of hospitalization, ICU length of stay, return to ICU, ventilator time, intraoperative complications, pulmonary complications, neurologic complications, renal complications, gastrointestinal complications, sternal wound infections, highest postoperative creatine kinase level, and units of blood products given during the procedure. Using logistic regression we controlled for eight confounding variables.

RESULTS

Patients undergoing OPCAB had a significantly shorter length of hospitalization (relative risk [RR] = 0.95; 95% CI, 0.91-0.99%), fewer pulmonary complications (RR = 0.45; 95% CI, 0.22-0.88%), fewer intraoperative complications (RR = 0.04; 95% CI, 0.0048-0.31%) fewer blood product units given (RR = 0.31; 95% CI, 0.14-0.42%) and lower postoperative creatine kinase (RR = 0.99; 95% CI, 0.98-0.99%). There were no considerable differences for the remaining nine outcomes, including mortality and neurologic complications.

CONCLUSIONS

Patients undergoing OPCAB had a considerably shorter length of hospitalization, had fewer pulmonary and intraoperative complications, and received a lower volume of blood products.

Haemodynamic effects of a milrinone infusion without a bolus in patients undergoing off-pump coronary artery bypass graft surgery

The haemodynamic effects of a continuous infusion of milrinone without an initial bolus dose were evaluated in patients undergoing off-pump coronary artery bypass graft surgery. After internal mammary artery harvest, milrinone 0.5 microg.min(-1).kg(-1) (29 patients) or a normal saline infusion (33 patients) was started and continued until all graft anastomoses were completed. Haemodynamic variables were recorded before application of the tissue stabiliser, at 1, 3, 5 and 10 min after the application of the stabiliser, and after its removal. The administration of a milrinone infusion was associated with a smaller decrease in cardiac output and mixed venous oxygen saturation during all the coronary artery anastomoses, with no severe complications and a decreased dose of norepinephrine infused to maintain systemic arterial pressure.

Off-pump myocardial revascularization is associated with less incidence of stroke in elderly patients

Several recent studies have highlighted the potential benefits of using off-pump coronary artery bypass (OPCAB) surgery, particularly in high-risk patients. The aim of this meta-analysis is to assess the effect of OPCAB on the incidence of stroke compared with coronary artery bypass grafting using cardiopulmonary bypass (CPB) in elderly patients. We performed a meta-analysis of all observational studies, published in MEDLINE between 1999 and 2002 and a comparison between the OPCAB and CPB techniques in elderly patients was performed with the outcome of interest being the incidence of stroke. Elderly patients were defined as those aged 70 years or older. Nine studies are included in the meta-analysis. The total number of subjects included was 4,475 patients, of which, 1,253 underwent OPCAB (28%) and 3,222 (72%) underwent CPB. The meta-analysis showed that the OPCAB technique was associated with significantly lower incidence of stroke in elderly patients compared with the CPB technique (1% vs 3%), with an odds ratio of 0.38% to 95% (CI, 0.22 to 0.65). We did not identify any significant heterogeneity and funnel plot asymmetry between the studies included in the meta-analysis. Meta-regression analysis including variables predicting stroke, mortality, and study characteristics did not show any associations affecting the calculated odds ratio of stroke. Despite the fact that this is a meta-analysis of observational studies and adjustment for differences in baseline risk factors between OPCAB and CPB patients was not possible, we believe that this study suggests that the OPCAB technique might be associated with reduced incidence of stroke in the elderly patients undergoing coronary artery bypass grafting.

Off-pump coronary artery bypass surgery: physiology and anaesthetic management †

Increasing interest is being shown in beating heart (off-pump) coronary artery surgery (OPCAB) because, compared with operations performed with cardiopulmonary bypass, OPCAB surgery may be associated with decreased postoperative morbidity and reduced total costs. Its appears to produce better results than conventional surgery in high-risk patient populations, elderly patients, and those with compromised cardiac function or coagulation disorders. Recent improvements in the technique have resulted in the possibility of multiple-vessel grafting in all coronary territories, with a graft patency comparable with conventional surgery. During beating-heart surgery, anaesthetists face two problems: first, the maintenance of haemodynamic stability during heart enucleation necessary for accessing each coronary artery; and second, the management of intraoperative myocardial ischaemia when coronary flow must be interrupted during grafting. The anaesthetic technique is less important than adequate management of these two major constraints. However, experimental and recent clinical data suggest that volatile anaesthetics have a marked cardioprotective effect against ischaemia, and might be specifically indicated. OPCAB surgery requires team work between anaesthetists and surgeons, who must be aware of each other's constraints. Some surgical aspects of the operation are reviewed along with physiological and anaesthetic data.

Combined use of off-pump techniques and a sutureless proximal aortic anastomotic device reduces cerebral microemboli generation during coronary artery bypass grafting

OBJECTIVE

Intraoperative cerebral microemboli are associated with the development of postoperative stroke and neurocognitive decline in patients undergoing coronary artery bypass grafting. Although cardiopulmonary bypass is responsible for the generation of a significant number of such emboli, the elimination of cardiopulmonary bypass alone has not been conclusively shown to improve neurocognitive outcome. The current study was performed to determine the effects of combined off-pump coronary artery bypass grafting and sutureless proximal aortic anastomotic techniques on the generation of intraoperative cerebral microemboli compared with standard coronary artery bypass grafting techniques of cardiopulmonary bypass and hand-sewn proximal anastomoses.

METHODS

Fifty-three patients underwent off-pump coronary artery bypass grafting by using the sutureless Symmetry aortic connector device (St Jude Medical, St Paul, Minn) for all proximal anastomoses. Eighteen of these patients received intraoperative transcranial Doppler ultrasonography to determine right- and left-sided cerebral microembolic counts. These results were compared with those obtained from a similar group of 17 patients undergoing standard coronary artery bypass grafting, in whom cardiopulmonary bypass and hand-sewn proximal anastomoses were used.

RESULTS

Our use of the proximal anastomotic device in patients undergoing coronary artery bypass grafting was safe, with no aortic complications, postoperative strokes, or in-hospital deaths. Microembolic counts to both the right and left cerebral circulation were significantly reduced in the patients undergoing off-pump coronary artery bypass grafting (right = 21.9 +/- 20.7 emboli, left = 24.9 +/- 19.2 emboli) compared with those in patients undergoing standard coronary artery bypass grafting (right = 181.6 +/- 85.3, left = 189.9 +/- 60.401, P <.0001).

CONCLUSIONS

Our use of a sutureless proximal anastomotic device during off-pump coronary artery bypass grafting is safe and significantly decreases cerebral microembolism when compared with standard coronary artery bypass grafting with cardiopulmonary bypass and hand-sewn anastomoses. Long-term follow-up is needed to determine the effects of this technical strategy on neurocognitive outcome.

Meta-analysis of short-term and mid-term outcomes following off-pump coronary artery bypass grafting

BACKGROUND

Uncertainty continues to surround the relative benefits and harms of conventional coronary artery bypass grafting (CABG) and off-pump coronary artery bypass grafting (OPCABG). Possible reasons are that high-quality studies have not comprehensively examined relevant patient outcomes and have enrolled a limited range of patients. Some studies may have been too small to detect clinically important differences in patient outcomes. The present study addresses these issues using meta-analysis.

METHODS

We comprehensively retrieved randomized and nonrandomized controlled studies according to predetermined criteria. We performed meta-analyses for each outcome and empirically determined whether potential biases that might result from differences in study design or patient characteristics actually biased a study's results. We also conducted sensitivity analyses and tested for publication bias.

RESULTS

Rates of perioperative myocardial infarction, stroke, reoperation for bleeding, renal failure, and mortality were lower after OPCABG than after CABG. Reductions in length of hospital stay, atrial fibrillation, and wound infection were also associated with OPCABG, but statistically significant differences among study results for these outcomes could not be explained by available information. Midterm (3 to 25 months) angina recurrence did not appear to differ between treatments; a trend was noticed toward lower reintervention rates with CABG, and a trend toward lower overall mortality with OPCABG, at least when performed at experienced centers. These midterm outcome results require confirmation.

CONCLUSIONS

Off-pump coronary artery bypass grafting appears to reduce length of hospital stay, operative morbidity, and operative mortality relative to on-pump CABG. More studies are required before firm conclusions can be drawn concerning the effect of OPCABG on midterm mortality, angina recurrence, and repeat intervention.

Determinants of Candidemia and Candidemia-Related Death in Cardiothoracic ICU Patients

STUDY OBJECTIVES

To develop and prospectively validate models of independent predictors of candidemia and candidemia-related death in cardiothoracic ICU (CICU) patients.

DESIGN

(1) An initial, prospective, one-center, case-control, independent predictor-model determining study; and (2) a prospective, two-center, model-validation study.

SETTING

The initial study was performed at the 14-bed CICU of the Onassis Cardiac Surgery Center, Athens, Greece; the model-validation study was performed at the Onassis Cardiac Surgery Center CICU and the 12-bed CICU of Henry Dunant General Hospital, Athens, Greece.

PATIENTS

In the initial study, 4,312 patients admitted to the Onassis Center CICU between March 1997 and October 1999 were considered for enrollment; 30 candidemic and 120 control patients (case/control ratio, 1/4) matched according to potential confounders were ultimately enrolled. In the model-validation study, 2,087 patients admitted to the Onassis and Henry Dunant CICUs between November 1999 and May 2002 were prospectively enrolled.

MEASUREMENTS AND RESULTS

Models of predictors of candidemia and associated death were constructed with stepwise logistic regression and subsequently validated. Independent candidemia predictors were ongoing invasive mechanical ventilation (IMV) > OR =10 days, hospital-acquired bacterial infection and/or bacteremia, cardiopulmonary bypass duration > 120 min, and diabetes mellitus. Model performance was as follows: sensitivity, 53.3%/57.9%; specificity, 100%/100%; positive predictive value (PPV), 100%/100%; negative predictive value (NPV), 88.9%/99.6%; and accuracy, 90.1%/99.6% (initial/model-validation study values, respectively). IMV > or =10 days and hospital-acquired bacterial infection/bacteremia were the two strongest candidemia predictors. APACHE (acute physiology and chronic health evaluation) II score > or =30 at candidemia onset independently predicted candidemia-related death with 80.0%/85.7% sensitivity, 80%/75% specificity, 66.7%/66.7% PPV, 88.9%/88.9% NPV, and 80.0%/78.9% accuracy (initial/model-validation study values, respectively).

CONCLUSIONS

We provided a set of easily determinable independent predictors of the occurrence of candidemia in CICU patients. Our results provide a rationale for implementing preventive measures in the form of independent predictor control, and initiating antifungal prophylaxis in high-risk CICU patients.

Off-pump coronary artery bypass graft surgery: the incidence of postoperative atrial fibrillation

Atrial fibrillation (AF) occurs in one quarter to one third of patients after coronary artery bypass graft surgery (CABG). Conventional CABG uses cardiopulmonary bypass, a process that is itself associated with a systemic vascular inflammatory response that contributes to postoperative morbidity. The avoidance of cardiopulmonary bypass is associated with a significant reduction in the inflammatory response and in the release of markers of myocardial necrosis when compared with conventional CABG. There is speculation that off-pump CABG may reduce the incidence of postoperative AF through reduced trauma, ischaemia, and inflammation. Current data, however, do not emphatically answer the question of whether the incidence of post-CABG AF is reduced by off-pump surgery. The evidence from both observational and randomised studies is conflicting and many studies have weaknesses in design, conduct, or interpretation. It remains an attractive hypothesis that postoperative AF is reduced by off-pump CABG but more robust data are required.

Comparison of cerebral embolization during off-pump and on-pump coronary artery bypass surgery

BACKGROUND

Coronary artery bypass surgery with cardiopulmonary bypass carries a significant risk of perioperative brain injury. At least 1% to 5% will suffer a stroke, and at 3-months postoperatively approximately 30% are reported to have cognitive impairment assessed by neuropsychologic testing. In off-pump surgery cardiopulmonary bypass is not used and instrumentation on the ascending aorta is reduced. The main aim of this study was to assess if off-pump surgery reduces intraoperative cerebral embolization.

METHODS

This was a prospective and randomized study of two comparable groups with regard to age, sex, years of education, preoperative cognitive functioning, and surgical characteristics. Fifty-two patients (29 off-pump) were monitored by the use of transcranial Doppler ultrasound for cerebral microembolization during surgery. Preoperative and postoperative clinical, cerebral magnetic resonance imaging, and neuropsychologic examinations were also carried out.

RESULTS

There was a significant reduction in the number of cerebral microemboli during off-pump compared with on-pump surgery (16.3 [range 0 to 131] versus 90.0 [range 15 to 274], p < 0.0001). No significant difference with regard to the incidence of neuropsychologic performance (decline in 29% off-pump, 35% on-pump) or neuroradiologic findings at 3 months was found, and there was no association between the number of cerebral microemboli and cognitive outcome.

CONCLUSIONS

This study clearly demonstrates that off-pump surgery leads to a reduction in intraoperative cerebral microembolization. A significant reduction in the number of off-pump patients with cognitive decline or ischemic brain lesions on cerebral magnetic resonance imaging could not be demonstrated in this relatively small patient population.

Benefits of off-pump bypass on neurologic and clinical morbidity: a prospective randomized trial

BACKGROUND

Neurologic and clinical morbidity after coronary artery bypass grafting (CABG) can be significant. By avoiding cardiopulmonary bypass, off-pump CABG (OPCAB) may reduce morbidity.

METHODS

Sixty patients (30 CABG and 30 OPCAB) were prospectively randomized. Neurocognitive testing was performed before the operation and 2 weeks and 1 year after the operation. Neurologic testing to detect stroke and (99m)Tc-HMPAO whole-brain single photon emission computed tomography scanning to assess cerebral perfusion were performed before the operation and 3 days afterward. Bilateral middle cerebral artery transcranial Doppler scanning was performed intraoperatively to detect cerebral microemboli. All examiners were blinded to treatment group. Clinical morbidity and costs were compared.

RESULTS

Coronary artery bypass grafting was associated with more cerebral microemboli (575 +/- 278.5 CABG versus 16.0 +/- 19.5 OPCAB (median +/- semiinterquartile range) and significantly reduced cerebral perfusion after the operation to the bilateral occipital, cerebellar, precunei, thalami, and left temporal lobes (p < or = 0.01). Cerebral perfusion with OPCAB was unchanged. Compared with base line, OPCAB patients performed better on the Rey Auditory Verbal Learning Test (total and recognition scores) at both 2 weeks and at 1 year (p < or = 0.05), whereas CABG performance was statistically unchanged for all cognitive measures. Patients who underwent CABG had more chest tube drainage (1389 +/- 1256 mL CABG versus 789 +/- 586 mL OPCAB, p = 0.02) and required more blood (3.9 +/- 5.8 U CABG versus 1.2 +/- 2.2 U OPCAB, p = 0.02), fresh frozen plasma (3.0 +/- 6.0 U CABG versus 0.5 +/- 2.2 U OPCAB, p = 0.03), and hours of postoperative use of dopamine (16.3 +/- 21.2 hours CABG versus 7.3 +/- 9.7 hours OPCAB, p = 0.04). These differences culminated in higher costs for CABG ($23,053 +/- $5,320 CABG versus $17,780 +/- $4,390 OPCAB, p < 0.0001). One stroke occurred with CABG, compared with none with OPCAB (p = NS). One OPCAB patient died because of a pulmonary embolus (p = NS).

CONCLUSIONS

Compared with CABG, OPCAB may reduce neurologic and clinical morbidity as well as cost.

Effects of off-pump coronary artery bypass grafting on patient outcome

BACKGROUND

Cardiopulmonary bypass (CPB) is associated with postoperative myocardial stunning, hypothermia, formation of microemboli, and systemic inflammatory response syndrome, all of which may prolong recovery from coronary artery bypass grafting (CABG) surgery. This study sought to compare outcomes in patients undergoing CABG off pump versus on pump.

METHODS

Outcomes, including mortality and several morbidities, were reviewed in 1,623 on-pump patients and 683 off-pump patients. Morbidities assessed included postoperative bleeding, incidence of multiorgan dysfunction, and neurologic complications. Chi-square and t-test analysis were used to determine statistical significance.

RESULTS

Mortality was 42% lower in the off-pump group than the on-pump group. Both critical care and total hospital length of stay were significantly shorter in the off-pump group. The incidence of postoperative bleeding requiring transfusion or a return to the operating room was reduced by 29% in the off-pump group and the incidence of multiorgan dysfunction was reduced by 31%. The off-pump patients also presented a significantly lower incidence of cerebral vascular accidents and seizures than on-pump patients.

CONCLUSIONS

We conclude that there is an association between improved patient outcome and off-pump CABG surgery. The outcomes of this study show a statistically significant decrease in mortality, critical care length of stay, total hospital stay, incidence of bleeding requiring transfusion or return to the operating room, amount of blood transfused, incidence of multiorgan dysfunction, cerebral vascular accidents, and seizures in off-pump patients when compared with on-pump patients. Such results support the use of myocardial revascularization off pump as an alternative to CABG surgery on pump. CABG surgery off pump may allow a better postoperative clinical course in patients who are candidates for the procedure.

On-pump coronary artery surgery versus off-pump exclusive arterial coronary grafting: a matched cohort comparison

BACKGROUND

It is unknown whether coronary artery bypass grafting without cardiopulmonary bypass and with exclusive use of arterial grafts (arterial off-pump CABG) offers any significant short-term advantages over standard CABG with cardiopulmonary bypass. Accordingly, we performed a comparison of the short-term outcomes of arterial off-pump and standard CABG patients matched for preoperative risk and number of grafts.

METHODS

We studied 90 consecutive arterial off-pump CABG patients during a 2-year period, obtained demographic and clinical features and surgical characteristics, and calculated their predicted surgical risk (EuroSCORE). Using a database of 750 contemporaneous patients treated with standard CABG, we created a matched cohort of 90 patients using an iterative process prioritizing number of grafts, target vessels, EuroSCORE, age, and sex. We compared the two groups for baseline features and short-term clinical outcomes.

RESULTS

There were no differences in age (65.9 versus 64.7 years), sex, EuroSCORE (3.3 versus 3. 6), number of grafts (2.1 versus 2.1), and preoperative left ventricular function. Arterial off-pump CABG, however, was associated with decreased duration of operation (213 versus 252 minutes; p < 0.0013), decreased peak postoperative troponin I levels (mean, 10.8 versus 29.1 ng/mL; p < 0.0001), decreased peak norepinephrine dose (2.3 versus 4.1 microg/ min; p < 0.0082), and decreased likelihood of receiving red blood cell transfusion (17.8% versus 40%; p = 0.0016). There were no differences in duration of intensive care unit or hospital stay, incidence of atrial fibrillation, or other clinical complications. There was one death in each group.

CONCLUSIONS

After matching for number of grafts and other important preoperative risk markers, arterial off-pump CABG still decreases the need for red blood cell transfusion and offers other moderate clinical advantages compared with standard on-pump CABG.

Vascular dementia may be the most common form of dementia in the elderly

Cerebrovascular lesions, mainly lacunes and white matter ischemia, are common in elderly patients with dementia. Vascular dementia (VaD) is the second most common cause of dementia, after Alzheimer's disease (AD). However, lacunar strokes have become an important factor in the clinical expression of AD. Also, population-based studies indicate that vascular risk factors increase the risk of developing AD. It is postulated here that the two main causes of VaD-stroke and ischemic heart disease (IHD)-may be responsible for the majority of cases of dementia in the elderly. STROKE RELATED VaD: Cerebrovascular disease (CVD) is the second leading cause of death worldwide. About 1/3 of stroke survivors [range: 25-41%] 65 years old and above develop VaD within 3 months following the ictus. In the USA alone, 125,000 new cases/year of VaD occur after ischemic stroke (about 1/3 of the 360,000 incident cases of AD). Therefore, more than 1 million elderly people are currently affected by poststroke VaD in the USA. Since current criteria identify "pure" cases of AD and VaD, it is likely that "AD plus CVD" ("mixed" dementia) could be responsible for a large number of cases currently diagnosed as probable AD. CARDIOGENIC VAD: By 2020, IHD leading to congestive heart failure (CHF) will become the leading cause of disability worldwide. Vascular cognitive impairment occurs in 26% of patients discharged from hospitals after treatment for CHF. Cognitive dysfunction correlates with left ventricular dysfunction and systolic blood pressure below 130 mm Hg. CHF is a leading cause of hospital admissions in Western nations (4.5 million cases in the USA alone) and is a growing problem in developing countries. Furthermore, over 800,000 patients/year undergo coronary artery bypass graft (CABG) surgery worldwide, including 300,000 patients in the USA. Measurable cognitive dysfunction occurs post-CABG in 80-90% of patients at hospital discharge. Long-term (5 years) incidence of cognitive defects is 42%. Finally, an international study found short-term postoperative cognitive dysfunction in 26% of patients (>60 years) after abdominal or orthopedic surgery; most of them may be instances of VaD. In conclusion, VaD may be the most underdiagnosed and undertreated form of dementia in the elderly.

Effects of off-pump coronary surgery on the mechanics of the respiratory system, lung, and chest wall: Comparison with extracorporeal circulation

OBJECTIVE

To compare the effects of cardiac surgery with and without extracorporeal circulation on the mechanics of the respiratory system, lung, and chest wall. We also determined the time course of those effects.

DESIGN

Prospective, controlled study.

SETTING

An eight-bed, cardiac-surgical intensive care unit at a university hospital.

PATIENTS

Two groups of patients scheduled for elective coronary bypass surgery were studied: ten patients with extracorporeal circulation and 13 patients without extracorporeal circulation.

INTERVENTIONS

Measurement of esophageal pressure after insertion of an esophageal balloon catheter to separate respiratory system mechanics into lung and chest wall components. Measurements were performed preoperatively after induction of anesthesia (control), immediately postoperatively at arrival in the intensive care unit (time 1), and after 3 hrs (time 2). In 12 of the 23 patients, measurements were also performed 6 hrs postoperatively (time 3).

MEASUREMENTS AND MAIN RESULTS

No significant differences concerning demographics or surgical procedure were noticed between the two groups. Respiratory system, chest wall, and lung mechanics were obtained using the technique of rapid airway occlusion during constant-flow inflation. In both the group with and without extracorporeal circulation there was a significant increase in static and dynamic elastance of the respiratory system and lung at times 1 and 2, which tended to decrease again at time 3; chest wall elastance significantly increased at times 2 and 3 in the group without extracorporeal circulation, whereas the increase in chest wall elastance in the group with extracorporeal circulation occurred earlier (also at time 1). Additional resistance of the respiratory system and lung remained unchanged; chest wall resistance, however, significantly increased in both groups. Work of breathing significantly increased in both groups at times 1 and 2. There was a significant reduction in the Pao2/Fio2 ratio in both groups at times 2 and 3. No significant differences between the groups at any moment were noticed.

CONCLUSIONS

Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.

Coronary artery bypass in patients 80 years and over: is off-pump the operation of choice?

BACKGROUND

Octogenarians are at increased risk for perioperative morbidity and mortality after coronary artery bypass. In this study we compared our experience with patients undergoing on-pump coronary artery bypass (CAB) and those undergoing off-pump coronary artery bypass (OPCAB) to assess outcomes.

METHODS

We used hospital database analysis in patients 80 years and older who underwent nonemergent coronary artery bypass with (N = 169) and without (N = 60) cardiopulmonary bypass from January 1999 through June 2001.

RESULTS

Both groups were at increased perioperative risk based on the Society of Thoracic Surgeons risk model (7.7% OPCAB vs 5.8% CAB, p = 0.03). There were no operative deaths in the OPCAB group but there were eight (4.7%) in the CAB group (p = NS). Perioperative stroke (0% OPCAB vs 7.1% CAB, p = 0.04), prolonged ventilation (1.7% OPCAB vs 11.8% CAB, p = 0.02), and transfusion rate (33% OPCAB vs 70.4% CAB, p < 0.001) were all lower in the OPCAB group. A shorter hospital stay (6.3 days OPCAB vs 11.5 days CAB, p < 0.001) resulted in lower hospital cost in the OPCAB group ($9,363 OPCAB vs $12,312 CAB, p < 0.001).

CONCLUSIONS

In this study, off-pump coronary artery bypass grafting in elderly patients was associated with fewer complications, a shorter hospital stay, and lower hospital cost. Off-pump coronary artery bypass grafting may be the operation of choice for octogenarians requiring surgical myocardial revascularization.

Embolization in atherosclerosis

Much has been learned about microembolization in the last two decades. The promising blood markers for brain injury will further enhance our future understanding of microembolic events. New surgical techniques, drugs, and devices have substantially reduced microembolization during carotid angioplasty, CEA, and CABG.

Comparison of two stabilizer concepts for off-pump coronary artery bypass grafting

BACKGROUND

This study was designed to evaluate the efficacy of two different stabilizer concepts for off-pump coronary artery bypass grafting.

METHODS

Between 2000 and 2001, 100 consecutive patients who underwent off-pump coronary artery bypass grafting were randomly assigned to two stabilization systems: the Medtronic Octopus 3 (n = 50) and the Genzyme Immobilizer (n = 50). During operation, two-dimensional cardiac surface motion was assessed by intravital microscopy using orthogonal polarization spectral imaging in 20 vessels at the anterior wall. Postoperative angiography of 47 vessels revealed anastomotic quality.

RESULTS

Patient demographics were similar in both groups regarding age, sex, ejection fraction, and New York Heart Association functional class. In 7 patients the randomized Immobilizer was rejected by the surgeon for lateral or posterior wall revascularization and subsequently switched to the Octopus device. Patients received 1.8 +/- 0.7 grafts in the Octopus and 1.6 +/- 0.5 in the Immobilizer group (p = not significant). Two-dimensional cardiac surface motion was significantly less using the Immobilizer (109.7 +/- 32.4 microm versus 423.5 +/- 129.6 microm; p < 0.001). Time required for anastomosis was significantly shorter in the Immobilizer group (11.3 +/- 3.5 versus 14.9 +/- 2.4 minutes; p < 0.001). Postoperative angiography showed no vessel occlusions but two anastomotic stenoses in each group.

CONCLUSIONS

Both stabilizers have been shown useful for off-pump coronary artery bypass grafting. The Immobilizer system showed better epicardial immobilization of the anterior wall resulting in shorter anastomosis times. However, because the Octopus 3 handling is more flexible and allows easier access to all vessels, it is the device of choice for posterior wall revascularization in our institution.

Neurological outcomes in coronary surgery: independent effect of avoiding cardiopulmonary bypass

BACKGROUND

Recent studies examining neuroprotective effects of off-pump coronary artery bypass grafting (CABG) have shown inconsistent results. We examined our database to quantify the independent effects of avoidance of cardiopulmonary bypass (CPB) and aortic manipulation on neurologic outcomes after CABG.

METHODS

A total of 2,327 consecutive cases undergoing isolated CABG between April 1997 and May 2001 were identified at our two institutions. Patients were divided into three groups: on CPB, off-pump with aortic manipulation, and off-pump without aortic manipulation. To control for the confounding effects of other risk factors, we performed a multivariate logistic regression analysis. Potential covariates considered in the logistic model included age, sex, redo operations, diabetes, chronic obstructive pulmonary disease, neurologic disease, peripheral vascular disease, ejection fraction, and priority of operation.

RESULTS

A total of 1,210 cases were performed on CPB, compared with 520 off-pump with aortic manipulation, and 597 off-pump without aortic manipulation. The incidence of focal neurologic deficit was 1.6% (n = 19) in the on-pump group, 0.4% (n = 2) in the off-pump with aortic manipulation group, and 0.5% (n = 3) for the off-pump without aortic manipulation group (p for trend = 0.027). The results of the multivariate logistic regression analysis demonstrated that use of CPB was a risk factor for focal neurologic deficit, with an odds ratio of 3.82 (95% confidence interval, 1.41 to 10.34; p = 0.005). Aortic manipulation did not significantly influence neurologic outcome in off-pump patients.

CONCLUSIONS

Off-pump operation, with or without aortic manipulation, reduces adverse neurologic outcomes compared with on-pump procedures.

Coronary-artery bypass surgery and the brain: persisting concerns

Mortality after coronary-artery bypass surgery (CABS) has fallen steadily over recent years. Concern remains, however, about the effect of this surgery on the brain. The problem of brain damage after CABS is multifactorial, involving microembolism, disturbed perfusion, metabolic derangement, and inflammatory responses. Microemboli numbers have been linked to the likelihood of neuropsychological deterioration after surgery. Risk factors for cerebral changes after CABS include older age, gender, neurological disease, diabetes, and calcification of the aorta. These risk factors are important because, in comparison with the early 1990s, patients undergoing CABS are now older and tend to have a greater number of comorbid conditions. Changes in surgical technique, such as the introduction of arterial-line filters and membrane oxygenators, have led to a reduction of both microemboli and neuropsychological disturbance. However, the problem persists, prompting further studies on surgical technique and neuroprotective strategies.

Intraoperative echocardiographic imaging of coronary arteries and graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass

BACKGROUND

No accepted approach exists for the intraoperative evaluation of the quality of coronary arteries and the technical adequacy of graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass.

METHODS AND RESULTS

We assessed the accuracy of high-frequency epicardial echocardiography and power Doppler imaging in evaluating coronary arteries during coronary artery bypass grafting without cardiopulmonary bypass. To validate measurements of coronary arteries and graft anastomoses by high-frequency epicardial echocardiography and power Doppler imaging, we compared luminal diameters determined by these methods with diameters determined histologically in a study of off-pump coronary artery bypass grafting in 20 dogs. Technical errors were deliberately created in 10 grafts (stenosis group). The results of these animal validation studies showed that the maximum luminal diameters of coronary arteries and graft anastomoses measured by high-frequency epicardial echocardiography (HEE) and power Doppler imaging (PDI) correlated well with the histologic measurements: HEE = 1.027 x Histologic measurements + 0.005 (P <.0001); PDI = 0.886 x Histologic measurements + 0.0453 (P =.0001). Similar results were found in the evaluation of the stenosis group: PDI = 0.991 x Histologic measurements + 0.074 (P <.0001). Subsequently, we demonstrated the clinical applicability of this approach in 12 patients who underwent minimally invasive or off-pump coronary artery bypass grafting. Twenty graft anastomoses were examined intraoperatively by high-frequency epicardial echocardiography and power Doppler imaging, and luminal diameters determined by power Doppler imaging were compared with those determined by postoperative coronary angiography. The results demonstrated that graft anastomosis by power Doppler imaging correlated well with the angiographic measurements: PDI = 1.018 x Angiographic measurements - 0.106 (P <.0001).

CONCLUSION

High-frequency epicardial echocardiography can provide meaningful information on the target coronary artery, and power Doppler imaging can accurately measure graft anastomoses and can detect technical errors and inadequacies during coronary artery bypass grafting without cardiopulmonary bypass.

Systemic inflammation and cardiac surgery: an update

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with the development of a systemic inflammatory response that can often lead to dysfunction of major organs. The systemic inflammation can be assessed intra- and postoperatively by measuring concentrations of inflammatory mediators in plasma and tissues. These concentrations, however, do not always correlate with the degree of observed organ dysfunction. Various strategies have been used to reduce inflammatory phenomena in patients undergoing CPB. Cardiac surgery without CPB has been performed increasingly with satisfactory results over the past few years. Attenuation of systemic inflammation and improved outcome in high risk patients are potential benefits of this technique. The emergence and expanding performance of cardiac surgical procedures without the use of CPB has given us an excellent tool to investigate the relative importance of CPB as a cause of systemic inflammation. Aprotinin is a protease inhibitor which is used in cardiac surgical patients for its haemostatic effects. Aprotinin has anti-inflammatory properties, the nature of which have not been completely clarified. This article presents a summary of the published literature investigating inflammatory response and organ dysfunction in patients who have cardiac surgery without CPB. It also presents an overview of recent data on the anti-inflammatory action mechanisms of aprotinin.