Impact of off-pump coronary artery bypass surgery on systemic inflammation: current best available evidence

The evolution of cardiovascular surgery in elderly patient: a review of current options and outcomes

Due to the increase in average life expectancy and the higher incidence of cardiovascular disease with advancing age, more elderly patients present for cardiac surgery nowadays. Advances in pre- and postoperative care have led to the possibility that an increasing number of elderly patients can be operated on safely and with a satisfactory outcome. Currently, coronary artery bypass surgery, aortic and mitral valve surgery, and major surgery of the aorta are performed in elderly patients. The data available show that most cardiac surgical procedures can be performed in elderly patients with a satisfactory outcome. Nevertheless, the risk for these patients is only acceptable in the absence of comorbidities. In particular, renal dysfunction, cerebrovascular disease, and poor clinical state are associated with a worse outcome in elderly patients. Careful patient selection, flawless surgery, meticulous hemostasis, perfect anesthesia, and adequate myocardial protection are basic requirements for the success of cardiac surgery in elderly patients. The care of elderly cardiac surgical patients can be improved only through the strict collaboration of geriatricians, anesthesiologists, cardiologists, and cardiac surgeons, in order to obtain a tailored treatment for each individual patient.

Effect of simulated extracorporeal circulation and glyceryl-tri-nitrate on leukocyte activation

OBJECTIVES

During extracorporeal circulation (ECC), a mechanical pump and an oxygenator replace the functions of the heart and lungs. The aim of this study is to test the effect of the nitric oxide donor glyceryl-tri-nitrate on activation markers of the innate immune system during simulated ECC.

DESIGN

Whole blood concentrations of selected leukocyte adhesion molecules, complement system components and myeloperoxidase (MPO) were measured in an in vitro system of simulated ECC.

RESULTS

Simulated ECC stimulated the expression of monocyte LPS-receptor CD14 and C3b-receptor CD35. Glyceryl-tri-nitrate significantly reduced the expression of leukocyte Fcγ receptor CD32 over time, compared to control. Simulated ECC increased the concentrations of MPO, terminal complement complex, and complement component C3a. Addition of glyceryl-tri-nitrate did not significantly affect these changes.

CONCLUSIONS

Simulated ECC induces the increased expression of some leukocyte markers. Glyceryl-tri-nitrate addition significantly reduces the expression of some leukocyte activation markers.

Does off-pump coronary artery bypass grafting negatively impact long-term survival and freedom from reintervention?

Recently published evidence has raised concerns about worse late mortality and increasing need for reintervention after off-pump coronary artery bypass grafting. We undertook this study to assess the impact of off-pump coronary artery bypass grafting on survival and freedom from reintervention at 10 years. From January 2002 to December 2002, 307 consecutive patients who had isolated multivessel off-pump coronary artery bypass grafting at our institution were compared to a control group of 397 patients that underwent multivessel on-pump coronary artery bypass grafting during the same period. In addition, univariate and risk-adjusted comparisons between the two groups were performed at 10 years. Kaplan-Meier survival was similar for the two cohorts. After adjusting for clinical covariates, off-pump coronary artery bypass grafting did not emerge as a significant independent predictor of long-term mortality (Hazard Ratio 0.91; 95% Confidence Interval 0.70-1.12), readmission to hospital for cardiac cause (Hazard Ratio 0.96; 95% Confidence Interval 0.78-1.10), or the need for reintervention (Hazard Ratio 0.93; 95% Confidence Interval 0.87-1.05). Off-pump coronary artery bypass grafting compared with on-pump coronary artery bypass grafting does not adversely impact survival or freedom from reintervention at a 10-year follow-up.

On-pump versus off-pump coronary artery bypass surgery: what is the status after ROOBY, DOORS, CORONARY and GOPCABE?

Off-pump coronary artery bypass surgery has been purported to be safer than conventional coronary artery bypass surgery performed using cardiopulmonary bypass. This theory was supported by a number of early series, but failed to be confirmed by a number of small, randomized, controlled trials. Conversely, it has been suggested that revascularization after off-pump surgery is associated with fewer grafts and lower graft patency, potentially leading to a higher risk of cardiovascular morbidity and need for repeated coronary interventions. Since 2009, four major randomized controlled trials have been published, increasing the level of evidence significantly.

Off pump coronary artery bypass surgery in a Nigerian teaching hospital

Coronary artery bypass grafting has not been previously reported in the Nigeria medical literature. We report the case performed in our institution of a 56 year old Nigerian female who underwent off pump coronary artery bypass surgery (OPCAB) for an ostial lesion of the left anterior descending coronary artery. The left internal mammary artery was successfully anastomosed to the left anterior descending coronary artery. The patient was discharged home after 2 weeks, following correction of problems with glycemic control.

Myocardial revascularization for the elderly: current options, role of off-pump coronary artery bypass grafting and outcomes

The increase in life expectancy has confronted cardiac surgery with a rapidly growing population of elderly patients requiring surgical myocardial revascularization. Recent advances in surgical and anesthetic techniques and improvements in postoperative care have made coronary artery bypass grafting an established therapeutic option for the treatment of coronary artery disease in this group of patients. However, conventional coronary artery bypass grafting on cardiopulmonary bypass is associated with significant risk and related morbidity and mortality in the elderly. In recent years off-pump coronary artery bypass grafting has emerged as a safe and less invasive strategy for surgical myocardial revascularization. Off-pump coronary artery bypass grafting by avoiding the deleterious effects of cardiopulmonary bypass can offer potential benefits to elderly patients requiring surgical myocardial revascularization. This review article provides an overview of the age-related cardiovascular changes, epidemiology of coronary artery disease in the elderly and focuses on outcomes of surgical myocardial revascularization with special emphasis on the impact of off-pump coro-nary artery bypass surgery in the elderly.

Preoperative hematocrit concentration and the risk of stroke in patients undergoing isolated coronary-artery bypass grafting

Background. Identification and management of risk factors for stroke following isolated coronary artery bypass grafting (CABG) could potentially lower the risk of such serious morbidity. Methods. We retrieved data for 30-day stroke incidence and perioperative variables for patients undergoing isolated CABG and used multivariate logistic regression to assess the adjusted effect of preoperative hematocrit concentration on stroke incidence. Results. In 2,313 patients (mean age 65.9 years, 73.6% men), 43 (1.9%, 95% CI: 1.4–2.5) developed stroke within 30 days following CABG (74.4% within 6 days). After adjustment for a priori defined potential confounders, each 1% drop in preoperative hematocrit concentration was associated with 1.07 (95% CI: 1.01–1.13) increased odds for stroke (men, OR: 1.08, 95% CI: 1.01–1.16; women, OR: 1.02, 95% CI: 0.91–1.16). The predicted probability of stroke for descending preoperative hematocrit concentration exceeded 2% for values <37% (<37% for men (adjusted OR: 2.39, 95% CI: 1.08–5.26) and <38% for women (adjusted OR: 2.52, 95% CI: 0.53–11.98), with a steeper probability increase noted in men). The association between lower preoperative hematocrit concentration and stroke was evident irrespective of intraoperative transfusion use. Conclusion. Screening and management of patients with low preoperative hematocrit concentration may alter postoperative stroke risk in patients undergoing isolated CABG.

Dissecting the possible influences of anesthesia and surgery on Alzheimer’s disease

SUMMARY Alzheimer’s disease (AD) is a neurodegenerative disease with late onset leading to significant morbidity and, ultimately, mortality. The prevalence of dementia in developed countries for individuals aged 65 years or over is approximately 10% currently, and the number of people with dementia is projected to increase by 350% by 2050. Older people frequently require anesthesia and surgery, such that by 2050 it is anticipated that 50% of all anesthetics will be administered to people aged 65 years or over. Anesthesia is known to be associated with neuropathological changes that mirror AD neuropathology in animal studies, and also with clinical cognitive changes known as postoperative cognitive dysfunction. This article will consider the evidence to date and whether we are able to dissect the possible influences of anesthesia and surgery. Identifying associations between postoperative cognitive dysfunction, dementia and AD is essential for developing strategies that will limit injury, and defer or prevent this disease. As a first step, preoperative cognitive assessment as part of routine perioperative management should become routine practice.

Open-heart surgery increases cerebrospinal fluid levels of Alzheimer-associated amyloid β

BACKGROUND

Neurocognitive dysfunction occurs frequently after open-heart surgery. It has been suggested that cognitive decline after cardiac surgery with cardiopulmonary bypass (CPB) could be a functional consequence of Alzheimer's disease (AD)-like neuropathological changes. The aim of the present study was to evaluate the cerebrospinal fluid (CSF) levels of amyloid β peptide (Aβ(1-42) ) and soluble fragments of amyloid precursor protein (sAPP) as well as the cerebral inflammatory response to open-heart surgery.

METHODS

Ten patients undergoing aortic valve replacement with CPB were included. CSF was obtained the day before and 24 h after surgery for assessment of CSF levels of Aβ(1-42) α-cleaved sAPP and β-cleaved sAPP (sAPP-β). Furthermore, CSF and serum levels of the inflammatory cytokines: tumour necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8) were also assessed.

RESULTS

Cardiac surgery with CPB increased CSF levels of Aβ(1-42) from 447 ± 92 to 641 ± 83 ng/l (P = 0.011), while CSF levels of sAPP-β decreased from 276 ± 35 to 192 ± 21 ng/ml (P = 0.031). CSF levels of TNF-α increased from ≤ 0.60 to 0.79 ± 0.26 ng/l (P = 0.043), IL-6 from 1.89 ± 0.53 to 22.8 ± 6.9 ng/l (P = 0.003) and IL-8 from 39.8 ± 7.8 to 139 ± 18.3 ng/l (P < 0.001).

CONCLUSIONS

Cardiac surgery with CPB causes a profound cerebral inflammatory response, which was accompanied by increased post-operative CSF levels of the AD biomarker Aβ(1-42) . We hypothesize that these changes may be relevant to Alzheimer-associated amyloid build-up in the brain and cognitive dysfunction after cardiac surgery with CPB.

Cardiopulmonary bypass during cardiac surgery modulates systemic inflammation by affecting different steps of the leukocyte recruitment cascade

Background

It is known that the use of a cardiopulmonary bypass (CPB) during cardiac surgery leads to leukocyte activation and may, among other causes, induce organ dysfunction due to increased leukocyte recruitment into different organs. Leukocyte extravasation occurs in a cascade-like fashion, including capturing, rolling, adhesion, and transmigration. However, the molecular mechanisms of increased leukocyte recruitment caused by CPB are not known. This clinical study was undertaken in order to investigate which steps of the leukocyte recruitment cascade are affected by the systemic inflammation during CPB.

Methods

We investigated the effects of CPB on the different steps of the leukocyte recruitment cascade in whole blood from healthy volunteers (n = 9) and patients undergoing cardiac surgery with the use of cardiopulmonary bypass (n = 7) or in off-pump coronary artery bypass-technique (OPCAB, n = 9) by using flow chamber experiments, transmigration assays, and biochemical analysis.

Results

CPB abrogated selectin-induced slow leukocyte rolling on E-selectin/ICAM-1 and P-selectin/ICAM-1. In contrast, chemokine-induced arrest and transmigration was significantly increased by CPB. Mechanistically, the abolishment of slow leukocyte rolling was due to disturbances in intracellular signaling with reduced phosphorylation of phospholipase C (PLC) γ2, Akt, and p38 MAP kinase. Furthermore, CPB induced an elevated transmigration which was caused by upregulation of Mac-1 on neutrophils.

Conclusion

These data suggest that CPB abrogates selectin-mediated slow leukocyte rolling by disturbing intracellular signaling, but that the clinically observed increased leukocyte recruitment caused by CPB is due to increased chemokine-induced arrest and transmigration. A better understanding of the underlying molecular mechanisms causing systemic inflammation after CPB may aid in the development of new therapeutic approaches.

Management of the clotting system: a European perspective

PURPOSE OF REVIEW

Coagulation management remains a challenge for anesthesiologists involved in cardiovascular surgery as the population undergoing surgery becomes older and presents with more comorbidities. These patients are frequently treated with one or more agents that directly affect coagulation. This review will discuss what is known and the treatments available to manage coagulation in the perioperative setting of cardiac surgery.

RECENT FINDINGS

New antithrombotics will be discussed as well as their proposed substitution in the preoperative period. The review will also describe the different products available in Europe for the treatment of bleeding and coagulopathy. Finally, the use of new monitoring devices will be discussed.

SUMMARY

The introduction of new drugs with different mechanisms of action adds to the complexity of coagulation management during cardiovascular surgery. Monitoring needs to be developed and improved, especially for evaluating platelet function.

Hypercoagulable state after off-pump coronary artery bypass grafting: evidence, mechanisms and implications

During the past decade, there has been a dramatic resurgence in the adoption of off-pump technology in coronary artery bypass surgery. This has inspired remarkable advances in the techniques of localized tissue stabilization and a greater understanding of the physiology of beating-heart mobilization and exposure. An avalanche of reports in the literature has demonstrated the early safety and efficacy of the procedure. However, despite abundant evidence validating the safety and efficacy of off-pump coronary artery bypass surgery, considerable controversy still persists regarding the long-term outcomes of this approach to myocardial revascularization. One area of concern, and even greater uncertainty, surrounds the issue of the existence of a hypercoagulable state after off-pump coronary artery bypass surgery. This article evaluates the current best evidence available from randomized controlled trials to assess the impact of off-pump coronary artery bypass surgery on coagulation, fibrinolysis and platelet activation, discusses the issue of hypercoagulability with emphasis on the mechanisms responsible for this actual or potential hypercoagulability, and explores the implications of this issue for clinical practice.

Impact of preoperative renal dysfunction in patients undergoing off-pump versus on-pump coronary artery bypass

BACKGROUND

The impact of the degree of renal dysfunction (RD) in patients undergoing coronary artery bypass grafting (CABG) ranging from normal to dialysis-dependence is not well defined.

METHODS

A retrospective review of 14,199 patients undergoing isolated, primary CABG from January 1996 to May 2009 at Emory Healthcare was performed. The estimated glomerular filtration rate (eGFR) was estimated by the Modification of Diet in Renal Disease formula: mild RD (eGFR 60 to 90 mL/min/1.73 m2), moderate RD (eGFR 30 to 59), severe RD (eGFR<30). A propensity scoring was used to balance the groups with 46 preoperative covariates. Multivariable logistic and Cox regression methods were used to determine the independent association of eGFR with mortality. Adjusted odds ratios were calculated for outcomes using the normal eGFR group as the reference. Kaplan-Meier curves were created to estimate long-term survival.

RESULTS

A total of 8,086 patients (57.0%) underwent off-pump coronary artery bypass (OPCAB) while 6,113 (43.0%) underwent on-pump CAB. Preoperative RD was common: Normal eGFR (n=3,503/14,199 [24.7%]); mild RD (7,236/14199 [51.0%]); moderate RD (2,860/14,199 [20.1%]); severe RD (283/14,199 [2.0%]); and preoperative dialysis (317/14,199 [2.2%]). Moderate to severe RD or preoperative dialysis was associated with worse adjusted in-hospital mortality: mild RD (odds ratio [OR] 1.42; 95% confidence interval [CI] 0.93 to 2.16; p=not significant); moderate RD (OR 3.55; 95% CI 2.32 to 5.43; p<0.05]; severe RD (OR 8.84; 95% CI 4.92 to 15.9; p<0.05); and dialysis-dependent (OR 9.64; 95% CI 5.45 to 17.0; p<0.05). Adjusted long-term survival was worse across levels of RD. The OPCAB patients with moderate to severe RD had worse long-term survival than on-pump CAB patients; however, the surgery types were similar among normal, mild, and dialysis patients.

CONCLUSIONS

Preoperative RD is common in the CABG population and is associated with diminished long-term survival. Improved early outcomes in patients with RD undergoing OPCAB diminished with worsening RD.

Totally arterial off-pump coronary artery bypass grafting after pneumonectomy

We report the case of an 82-year-old man who underwent triple coronary artery bypass grafting with arterial grafts, who 20 years previously underwent left pneumonectomy for lung cancer. Computed tomography (CT) presented a marked shift of the heart and great vessels into the left hemithorax. Off-pump coronary artery bypass grafting was performed through a left thoracotomy, in which the left internal thoracic, right gastroepiploic, and radial arteries were used. He was extubated 1 hour post-operatively and had an uneventful recovery.

Comparison of inflammatory response during on-pump and off-pump coronary artery bypass surgery

PURPOSE

On-pump coronary artery bypass graft (CABG) surgery has been traditionally associated with a higher magnitude of inflammatory response than off-pump CABG. However with the development of polymer-coated biocompatible extracorporeal circuits, we wanted to see if cardiopulmonary bypass still played an important role in triggering this inflammatory response.

METHODS

In this prospective observational study, 33 patients undergoing CABG surgeries (25 on-pump and 8 off-pump patients) were studied. Serial plasma cytokine (TNF IL-6, IL-10) and procalcitonin concentrations were measured at different time-points during and after the surgery. Demographic and baseline clinical data, intra-operative management details and post-operative complications were also collected from the patients' charts.

RESULTS

Plasma levels of all 4 mediators increased during surgery and returned towards normal postoperatively. There were no differences between groups for any mediator at any time-point.

CONCLUSIONS

We conclude that with the use of recent polymer-coated biocompatible extracorporeal circuits, the inflammatory response triggered by on-pump CABG becomes very similar in magnitude and pattern to that triggered by off-pump CABG. Thus, the surgical procedure contributes to most of the inflammatory response, with the extra-corporeal circuit having minimal to no effect on this response.

Expression of thrombomodulin on monocytes is associated with early outcomes in patients with coronary artery bypass graft surgery

Thrombomodulin (TM) mediates blood coagulation and inflammation and is expressed constitutively on resting monocytes. This expression might be a key regulator of monocyte-related inflammation. Conventional cardiopulmonary bypass (CPB), beating-heart CPB, and off-pump techniques have been used widely in cardiac surgery. Although beating-heart CPB and off-pump techniques have reduced postoperative inflammation significantly, the underlying mechanisms remain unclear. Whether CPB affects the expression of TM and changes the actual immune capacity of monocytes is also unknown. In this study, we analyzed TM expression on monocytes and in plasma among patients undergoing elective coronary artery bypass graft surgery. The days spent in an intensive care unit (ICU) and incidence of fever in the ICU were significantly lower in the beating-heart CPB and off-pump groups than in the conventional CPB group. Enzyme-linked immunosorbent assay showed a significant increase in TM at 30 min after the commencement of CPB and at the end of surgery in the conventional CPB group, whereas the level increased less markedly in the beating-heart CPB group. Flow cytometry showed that conventional CPB markedly reduced the expression of TM on monocytes. Based on monocyte chemotaxis analysis and an actin polymerization assay, we propose that TM expression on monocytes is associated with systemic inflammation. We conclude that the beating-heart CPB and off-pump techniques have a lower impact on patients than conventional CPB. The reduced incidence of fever and shorter ICU stay seem to be associated predominantly with the lower concentration of TM in plasma and with a higher expression of TM on monocytes.

Reoperative off-pump coronary artery bypass grafting: current outcomes, concerns and controversies

Increasing numbers of patients have undergone coronary artery bypass grafting in the last four decades. As a result, the incidence of reoperative coronary artery bypass grafting is rising. Reoperative procedures pose several technical difficulties and are associated with increased operative risks, which exceed those of the initial revascularization. As the incidence of reoperative procedures is increasing so is the experience of reoperative coronary artery bypass grafting, with the resultant evolution of several alternative strategies to lower the operative risks. These strategies include alternative techniques for re-entry, strict avoidance of graft manipulation to minimize the risk of graft atheroembolism, and modification of the method of myocardial protection, depending on the status of the native coronary circulation and the patency of venous or arterial grafts. Off-pump coronary artery bypass grafting is one such technique that, through the avoidance of inherent risks of cardiopulmonary bypass, has the potential to reduce the morbidity associated with reoperative coronary artery bypass grafting. This article evaluates the current outcomes of reoperative off-pump coronary artery bypass grafting, and highlights the concerns and controversies associated with this strategy.

Effect of preoperative statin therapy on myocardial protection and morbidity endpoints following off-pump coronary bypass surgery in patients with elevated C-reactive protein level

BACKGROUND

The aim of this study was to investigate the effects of preoperative statin therapy on myocardial protection and morbidity endpoints following off-pump coronary bypass graft surgery (OPCAB) in patients with elevated serum high-sensitivity C-reactive protein (hs-CRP) levels.

METHODS

Of the 492 patients who underwent multivessel OPCAB from March 2007 to February 2009, the records of 144 patients whose baseline hs-CRP level > 2 mg/L were reviewed. According to the history of preoperative statin therapy for at least one week, patients were classified as either statin group or control group (72 subjects each). Preoperative and operative characteristics and postoperative data including troponin (Tn)-T level and major morbidity endpoints were obtained and compared. Major morbidity endpoints were defined as permanent stroke, renal dysfunction, hemostatic re-exploration, deep sternal wound infection, and the number of patients requiring prolonged ventilation.

RESULTS

Preoperative and operative characteristics were similar between the two groups. There were no significant differences in the incidence of morbidity endpoints between the two groups, except for the number of patients requiring dialysis, which was significantly lower in the statin group (8 vs. 1, P = 0.033). Tn-T level at 24 h after surgery was also significantly lower in the statin group.

CONCLUSIONS

In this study, we observed beneficial effects of preoperative statin therapy for at least one week in terms of less myocardial enzyme release and fewer patients requiring dialysis following OPCAB in patients whose preoperative hs-CRP was elevated.

Survival of patients on dialysis having off-pump versus on-pump coronary artery bypass surgery in the United States

BACKGROUND

Patients on dialysis sustain at least a threefold higher in-hospital mortality rate and markedly higher long-term mortality following coronary artery bypass graft surgery than the general population. Smaller studies have suggested that dialysis patients have superior outcomes with off-pump compared with on-pump coronary artery bypass surgery.

METHODS

From the United States Renal Data System database, 13,085 patients on dialysis having first coronary artery bypass surgery between 2001 and 2006 were identified. Of these, 2335 (17.8%) had off-pump coronary artery bypass surgery. The Kaplan-Meier method was used to estimate survival of patients having off-pump coronary artery bypass and patients having on-pump coronary artery bypass. A Cox proportional hazards model was used to assess effects of off-pump coronary artery bypass on mortality with adjustment for baseline patient characteristics.

RESULTS

Off-pump coronary artery bypass surgery was associated with significantly reduced all-cause mortality compared with on-pump coronary artery bypass surgery (hazard ratio 0.92, 95% confidence interval 0.86-0.99, P = .02). The observed survival benefit was most notable in the first year after surgery (70.3% vs 68.7%) and was lost 2 years after surgery (55.4% vs 55.2%). No difference was noted in the in-hospital mortality rate with off-pump coronary artery bypass surgery versus on-pump coronary artery bypass surgery (9.7% vs 11.0%, P = .06). Cardiac mortality during the follow-up period was similar (23.6% vs 23.8%; adjusted hazard ratio 0.95, 95% confidence interval 0.86-1.04, P = .26). Use of internal thoracic grafts was independently associated with improved survival after coronary artery bypass surgery (hazard ratio, 0.92; 95% confidence interval, 0.87-0.98, P = .0057).

CONCLUSIONS

Patients on dialysis sustain high in-hospital and 2-year mortality rates after coronary artery bypass surgery. Off-pump coronary artery bypass is associated with modestly increased survival compared with on-pump coronary artery bypass, a benefit most marked early after off-pump coronary artery bypass.

Melatonin, a potent regulator of hemeoxygenase-1, reduces cardiopulmonary bypass-induced renal damage in rats

Acute renal dysfunction is a frequent complication after cardiac surgery with cardiopulmonary bypass (CPB). This study was designed to evaluate the potential protective effect of melatonin on CPB-induced renal damage in a rat model. Forty male Sprague-Dawley rats were randomly divided into four groups: sham, control (CPB + placebo), low dose of melatonin (CPB + 10 mg/kg melatonin) and high dose of melatonin (CPB + 20 mg/kg melatonin). Blood samples were collected at the beginning, at the end of CPB, and at 0.5, 1, 2, 3, and 24 hr postoperation. Serum creatinine and blood urea nitrogen levels were assayed. Rats were killed 24 hr after surgery, the histologic appearance of the kidney and malondialdehyde (MDA), myeloperoxidase (MPO), catalase (CAT) and superoxide dismutase (SOD) contents were determined. The expression levels of hemeoxygenase-1 (HO-1) protein and gene were determined using western blotting and real-time PCR, respectively. In the control group, CPB surgery significantly increased urea, creatinine levels in serum, MDA and MPO levels in tissues, while decreasing SOD and CAT activities in tissues. Histopathologic findings of the control group confirmed that there was renal impairment by cast formation and tubular necrosis in the tubular epithelium. These changes were markedly reversed in both low dose of melatonin and high dose of melatonin groups. Furthermore, HO-1 gene transcript and protein were significantly upregulated in the kidney tissues after melatonin treatment compared with the placebo treatment. Our findings show that melatonin was effective in preventing CPB-induced renal damage probably through its antioxidant function and upregulation of HO-1.

Predictive value of C-reactive protein for major postoperative complications following off-pump coronary artery bypass surgery: prospective and observational trial

BACKGROUND

To prospectively investigate the predictive value of the preoperative C-reactive protein (CRP) concentration for major postoperative complications following off-pump coronary artery bypass (OPCAB) surgery.

METHODS AND RESULTS

From January 2007 to December 2007, 185 consecutive patients scheduled for elective OPCAB surgery were allocated to a low-CRP group (n=137, CRP <0.3 mg/dl) and a high-CRP group (n=48, CRP > or = 0.3 mg/dl). The incidence of major postoperative complications, defined as postoperative myocardial infarction, and 5 major morbidity endpoints including permanent stroke, renal dysfunction, any cardiac surgery reoperation, ventilation for more than 48 h, and deep sternal wound infection were assessed and compared. Multivariate logistic regression was used to determine the predictors of major postoperative complications. Patients in the high-CRP group had a significantly higher overall incidence of major postoperative complications, particularly renal dysfunction. In the multivariate logistic regression model, adjusting all the significant univariate predictors, baseline CRP >0.3 mg/dl and preoperative chronic renal failure (CRF) remained as significant independent predictors of major postoperative complications.

CONCLUSIONS

Elevated preoperative CRP level and/or preoperative CRF indicate increased risk of developing major postoperative complications, particularly acute postoperative renal dysfunction in patients undergoing OPCAB surgery.

Syndecan-1 plasma levels during coronary artery bypass surgery with and without cardiopulmonary bypass

The glycocalyx covering the endothelium is shed during ischemia and reperfusion. The shedding is accompanied by increased levels of the glycocalyx component syndecan-1 in the circulation. Our aim was to compare plasma levels of syndecan-1 in patients undergoing coronary artery bypass grafting (CABG), with or without the use of cardiopulmonary bypass (CPB). Syndecan-1 plasma concentrations were measured in patients undergoing CABG on-pump (n = 22) or off-pump (n = 22). The syndecan-1 concentration increased significantly from 29.5 ± 4.6 ng/mL at baseline to 98.7 ± 9.8 ng/mL (p < 0.01) after the start of CPB or 30 minutes after the induction of anesthesia in the off-pump group. There were no significant differences in peak syndecan-1 plasma concentrations between on-pump and off-pump patients. Plasma levels of syndecan-1 increased significantly during CABG, with or without the use of CPB. There were no significant differences in syndecan-1 concentrations in the two groups.

Aspirin in coronary artery bypass surgery: new aspects of and alternatives for an old antithrombotic agent

The success of coronary artery bypass graft surgery (CABG) depends mainly on the patency of the graft vessels. Aortocoronary vein graft disease is comprised of three distinct but interrelated pathological processes: thrombosis, intimal hyperplasia and atherosclerosis. Early thrombosis is a major cause of vein graft attrition during the first month after CABG, while during the remainder of the first year, intimal hyperplasia forms a template for subsequent atherogenesis, which thereafter predominates. Platelets play a crucial role in the pathophysiology of graft thrombosis and aspirin is the primary antiplatelet drug that has been shown to improve vein graft patency within the first year after CABG. Nevertheless, a significant number of grafts still occlude in the early postoperative period despite 'appropriate' aspirin treatment. Moreover, laboratory investigations showed that the expected inhibition of platelet function is not always achieved. This has been called 'aspirin nonresponse' or 'aspirin resistance', although a uniform definition is lacking. The finding that a considerable number of patients show an impaired antiplatelet effect of aspirin after CABG brought new insight into the discussion concerning poor patency rates of bypass grafts: the early period after CABG shows a coincidence of an increased risk for bypass thrombosis (amongst others, due to platelet activation and endothelial cell disruption of the graft) and an increased prevalence of aspirin resistance. Hitherto, the underlying mechanisms of aspirin resistance are uncertain and largely hypothetical; amongst others, increased platelet turnover, enhanced platelet reactivity, systemic inflammation, and drug-drug interaction are discussed. Up to now available data concerning the clinical outcome of aspirin resistant CABG patients are limited, and there is evidence that platelets of patients with graft thrombosis are more likely to be resistant to aspirin compared with patients without thrombotic events. Many publications concerning aspirin resistance are available today, but reports addressing this topic in CABG patients are sparse. This review summarises recent insights into the antiplatelet treatment after CABG and describes the clinical benefit, but also the therapeutic failure of the well-established drug aspirin. Moreover, possible pharmacological approaches to improve antithrombotic therapy in aspirin nonresponders among CABG patients are discussed.