Antioxidant activity in off and on-pump coronary artery bypass grafting and valve replacement surgery

OBJECTIVES

Cardiac surgeries initiate oxidative stress, increasing organ dysfunction development and mortality. The present study investigated the superoxide dismutase (SOD) activity, as an antioxidant enzyme, in patients undergoing coronary artery bypass (CABG) and heart valve replacement surgeries.

METHODS

A prospective study was performed on patients with proven coronary artery disease (CAD) or valvular heart disease (VHD) candidates for on- or off-pump CABG and valve replacement surgery. Serum SOD activity was measured preoperatively, at 24 h postoperatively, and at the time of discharge. In addition, echocardiography was performed before surgery and at discharge.

RESULTS

A total of 48, 51, and 47 patients were enrolled in the on-pump, off-pump CABG, and valve replacement groups, respectively. Baseline serum SOD activity showed no significant association with BMI, age, and blood pressure in either CAD or VHD patients. The SOD values decreased at the 24 h postoperative time and then increased at the time of discharge in all groups, except for a slight decrease in the on-pump group. The changes in serum SOD values were not significantly different for the three surgical groups.

CONCLUSIONS

The serum SOD activities fell significantly after CABG and valve replacement surgery. Further investigation is emphasized for the role of SOD in oxidative stress after cardiac surgery.

Changes in serum zinc and copper concentrations in patients with cardiovascular disease following cardiac surgery

The trace elements copper (Cu) and zinc (Zn) are essential for maintaining oxidative balance, and cardiac surgery is known to provoke an increase in oxidative stress. We investigated the variations in serum Zn and Cu concentrations before and after surgery in patients undergoing on- and off-pump CABG and heart valve replacement. We performed a prospective study on patients undergoing on- or off-pump CABG, or heart valve replacement surgery (48, 51, and 47 patients, respectively). Venous blood samples were obtained, and serum Cu and Zn concentrations were measured preoperatively, 24 h postoperatively, and the time of discharge. In addition, echocardiography was carried out on all patients before surgery and again on the day of discharge. We found the temporal changes in Cu, Zn, and Zn/Cu ratio were significantly different in all three groups of surgery (p < 0.05). In each group, Cu and Zn values and Zn/Cu ratio decreased at the 24-h postoperative time and rose at the discharge time. There were no significant differences between surgery groups in the changes induced in Zn or Cu values (p > 0.05). In conclusion, the concentrations of Cu and Zn were markedly reduced after on- and off-pump CABG and valve replacement surgery. This may suggest that supplementary Zn and Cu administration could be beneficial during open-heart surgeries. However, more long-term studies with more patients are needed to confirm this hypothesis.

Incidence of postoperative atrial fibrillation in patients undergoing on-pump and off-pump coronary artery bypass grafting

OBJECTIVE

To determine the incidence of postoperative atrial fibrillation in patients undergoing on-pump and off-pump coronary artery bypass grafting.

METHODS

A retrospective study with analysis of 230 medical records between January 2011 and October 2013 was conducted.

RESULTS

Fifty-six (24.3%) out of the 230 patients were female. The average age of patients undergoing on-pump coronary artery bypass grafting was 59.91±8.62 years old, and off-pump was 57.16±9.01 years old (P=0.0213). The average EuroSCORE for the on-pump group was 3.37%±3.08% and for the off-pump group was 3.13%±3% (P=0.5468). Eighteen (13.43%) patients who underwent off-pump coronary artery bypass grafting developed postoperative atrial fibrillation, whereas for the onpump group, 19 (19.79%) developed this arrhythmia, with no significant difference between the groups (P=0.1955).

CONCLUSION

Off-pump coronary artery bypass grafting did not reduce the incidence of atrial fibrillation in the postoperative period. Important predictors of risk for the development of this arrhythmia were identified as: patients older than 70 years old and presence of atrial fibrillation in perioperative period in both groups, and non-use of beta-blockers drugs postoperatively in the on-pump group.

Long-term follow-up of off-pump and on-pump coronary artery bypass grafting

OBJECTIVE

Despite increasing recognition of the benefits of off-pump coronary artery bypass grafting (CABG), concerns persist regarding its impact on long-term mortality and freedom from reintervention. In this study, we assessed the impact of off-pump CABG on long-term outcomes.

METHODS

From January 2002 to December 2002, a total of 307 consecutive patients who underwent isolated multivessel off-pump CABG at our institution were compared with a control group of 397 patients who underwent multivessel on-pump CABG during the same period. Perioperative data were prospectively collected and compared. In addition, univariate and risk-adjusted comparisons between the two groups were performed at 10 years.

RESULTS

After adjusting for clinical covariates, off-pump CABG did not emerge as a significant independent predictor of long-term mortality [hazard ratio (HR), 0.91; 95% confidence interval (CI), 0.70-1.12], readmission to hospital for cardiac cause (HR, 0.96; 95% CI, 0.78-1.10), or the need for reintervention (HR, 0.93; 95% CI, 0.87-1.05).

CONCLUSIONS

At long-term follow-up, off-pump CABG remains a safe and effective myocardial revascularization strategy with no adverse impact on survival or freedom from reintervention.

Concomitant off-pump coronary artery bypass grafting results in improved in-hospital outcomes for patients with ischemic mitral regurgitation undergoing surgery

OBJECTIVE

Surgical management of ischemic mitral regurgitation (IMR) has primarily consisted of revascularization with or without the addition of mitral valve repair or replacement. We hypothesize that performing off-pump coronary artery bypass (OPCAB) grafting before fixing MR improves in-hospital outcomes for patients with IMR undergoing surgery.

METHODS

From January 2000 through December 2010, a total of 96 consecutive patients with moderate or severe IMR, as determined by preoperative echocardiography, underwent on-pump coronary artery bypass grafting (CABG) (n = 66) or OPCAB (n = 30) revascularization with concomitant mitral valve repair or replacement. A retrospective analysis of a prospectively collected cardiac surgery database (PATS; Dendrite Clinical Systems, Oxford, UK) was performed. In addition, medical notes and charts were reviewed for all study patients.

RESULTS

The 2 groups had similar preoperative demographic and EuroSCORE risk-stratification characteristics. The operative mortality rate for the entire cohort was 9.4%. Patients who underwent OPCAB grafting had a lower operative mortality than those who underwent CABG (3.3% versus 12.1%; P = .006). The mean ±SD cardiopulmonary bypass time (82.7 ± 34.7 minutes versus 160.7 ± 45.2 minutes; P < .001) and cross-clamp time (49.0 ± 22.4 minutes versus 103.4 ± 39.5 minutes; P < .001) were significantly shorter in the off-pump group than in the on-pump group. The OPCAB group also had significantly less in-hospital morbidity and shorter stays in the intensive care unit and the hospital.

CONCLUSION

Our analysis shows that OPCAB grafting (compared with conventional CABG) before repairing MR is associated with favorable in-hospital outcomes for patients undergoing surgery for IMR.

Off-pump coronary artery bypass surgery induces prolonged alterations to host neutrophil physiology

Persistent alteration to host polymorphonuclear cell (PMN) physiology has been demonstrated after cardiac surgery performed with cardiopulmonary bypass (CPB). However, to date, PMN physiology and function beyond the first 24 h have not been investigated after cardiac surgery performed without CPB (off-pump coronary artery bypass grafting [OPCAB]). Blood samples of 15 patients were collected preoperatively and on days 1, 3, and 5 after OPCAB. Expression of CD11b, CD18, CBRM1/5, and CD62L were assessed by flow cytometry under resting conditions and after stimulation with formyl methionyl-leucyl-phenylalanine (fMLF), and respiratory burst activity was also measured. Under resting conditions, PMN CD11b, CBRM1/5, and CD62L expressions were minimally altered by surgery. Compared with the response of preoperative PMNs, PMNs assayed on days 3 and 5 after OPCAB demonstrated a significantly blunted increase in the expression of CD11b and CBRM1/5 after fMLF, significantly diminished shedding of CD62L in response to platelet-activating factor and fMLF, and diminished superoxide production after stimulation on day 3. The alteration of PMN function after OPCAB implies that cardiac surgical trauma without CPB directly modulates host PMN physiology.

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.

Anaortic, total-arterial, off-pump coronary artery bypass surgery: why bother?

Coronary artery bypass grafting (CABG) remains the standard of care for multi-vessel coronary disease. However, the increased rate of peri-operative stroke reported after surgery compared to percutaneous coronary intervention (PCI) remains of concern. Anaortic, total-arterial, off-pump coronary artery bypass (OPCAB) grafting is a technique that offers the main advantages of surgical revascularisation with a rate of stroke that is equivalent to that of PCI. Some recent trials comparing conventional on-pump CABG with OPCAB have questioned the efficacy of the off-pump technique - these are most often performed with manipulation of the ascending aorta. We review the potential benefits of the anaortic, total-arterial OPCAB technique to explain why it is being employed by an increasing number of surgeons.

Preconditioning with repeated hyperbaric oxygen induces myocardial and cerebral protection in patients undergoing coronary artery bypass graft surgery: a prospective, randomized, controlled clinical trial

OBJECTIVES

To evaluate the cerebral and myocardial protective effects of hyperbaric oxygen preconditioning in both on-pump and off-pump coronary artery bypass graft surgery.

DESIGN

A prospective, randomized, single-blinded study including patients scheduled for elective on-pump or off-pump surgery between December 2007 and February 2009.

SETTING

A tertiary care university teaching hospital.

PARTICIPANTS

Forty-nine elective on-pump or off-pump coronary artery bypass graft surgery patients.

INTERVENTIONS

Patients were randomized to either the control (15 patients with on-pump procedure and 10 patients with off-pump procedure, respectively) or hyperbaric oxygen (HBO; 14 patients with on-pump procedure and 10 patients with off-pump procedure, respectively) groups. Patients in the HBO groups underwent preconditioning for 5 days before surgery.

MEASUREMENTS AND MAIN RESULTS

On-pump coronary artery bypass graft surgery patients preconditioned with HBO had significant decreases in S100B protein, neuron-specific enolase, and troponin I perioperative serum levels compared with the on-pump control group. Postsurgically, patients in the on-pump HBO group had a reduced length of stay in the intensive care unit and a decreased use of inotropic drugs. Serum catalase activity 24 hours postoperatively was significantly increased compared with the on-pump control group. In the off-pump groups, there was no difference in any of the same parameters.

CONCLUSIONS

Preconditioning with HBO resulted in both cerebral and cardiac protective effects as determined by biochemical markers of neuronal and myocardial injury and clinical outcomes in patients undergoing on-pump coronary artery bypass graft surgery. No protective effects were noted in off-pump coronary artery bypass graft surgery.

Coronary artery bypass grafting with and without manipulation of the ascending aorta--a meta-analysis

BACKGROUND

The main criticism of surgery in the SYNTAX trial was increased rate of stroke when compared to percutaneous coronary intervention. We aimed to determine whether avoiding aortic manipulation would decrease the rate of stroke.

METHOD

We performed a meta-analysis of seven studies comparing coronary artery bypass grafting (CABG) with and without manipulation of the ascending aorta.

RESULTS

When anaortic off-pump coronary artery bypass grafting (OPCAB) was compared with conventional CABG, the rate of stroke was 0.38% vs. 1.87% (p<0.0001). When anaortic OPCAB was compared with OPCAB using a side-clamp or proximal graft anastomosis device the rate of stroke was 0.31% vs. 1.35% (p=0.003).

CONCLUSION

Avoiding aortic manipulation during CABG may decrease the rate of peri-operative stroke.

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.

Early Patency Evaluation of New Distal Anastomotic Device in Internal Mammary Artery Grafts Using Computed Tomography Angiography

Introduction

Traditional coronary artery bypass grafting is performed using a hand sewn technique. The C-Port xA and Flex A anastomotic stapling devices (Cardica Inc., Redwood City, CA) were cleared by the Food and Drug Administration for use in distal coronary anastomoses in November 2006 and April 2007, respectively. They provide the ability to create a compliant, consistently reproducible, and automated anastomosis. Multidetector computed tomography (CT) has been shown to be effective in evaluating coronary artery bypass graft patency.

Methods

The first 24 patients to undergo internal mammary artery (IMA) anastomosis using the automated device in our practice were included in the study. Twenty-five IMA grafts (24 left IMA and 1 right IMA) were created using the C-Port xA or Flex A anastomotic device as part of multivessel off-pump coronary revascularization by sternotomy. Graft patency was evaluated at 30 days in the first 10 grafts and at 90 days in the next 15 grafts using multidetector (64 slice) CT.

Results

There were no device failures. There were no perioperative strokes, myocardial infarctions, or deaths. All 10 IMA grafts evaluated at 30 days were patent using multidetector CT. One of the 15 IMA grafts studied at 90 days was occluded using multidetector computed tomography.

Conclusions

The C-Port xA and Flex A distal anastomotic devices provided a safe and effective means to create a left IMA-left anterior descending artery anastomoses in coronary bypass surgery with excellent short to midterm patency in this early experience. Long-term follow-up is warranted. These findings will have important implications for future sternal sparing coronary bypass surgery.