The effects of on-pump and off-pump coronary artery bypass surgery on oxidative stress and cerebral oxygenation: a prospective observational study.

Background/aim: In this prospective observational study, our goal was to investigate the relationship between serum levels of oxidative stress (OS) parameters and regional cerebral oxygen saturation (rSO2) in addition to evaluating postoperative clinical outcomes among patients undergoing coronary artery bypass graft surgery (CABG). Materials and methods: This study comprised 64 adult patients undergoing elective CABG (on-pump [n = 48] and off-pump [n = 16]) procedures. Serum OS levels and rSO2 values were measured intraoperatively at three specific time points: T1 (after induction), T2 (15 min before aortic cross-clamp removal or the final distal anastomosis), and T3 (15 min after aortic cross-clamp removal or the last distal anastomosis). Results: Serum OS and lactate values demonstrated higher levels at T2 and T3 (p < 0.001), while rSO2 values were lower at T2 (p = 0.024) in the on-pump CABG group compared to the off-pump CABG group. The rSO2 values at T2 exhibited a negative correlation with OS parameters, lactate levels at T2 and T3, aortic clamp time, postoperative mechanical ventilation time, and intensive care unit stay length. In the multivariate linear regression analysis (R2 = 0.181, p = 0.001), lactate values at T2 emerged as the sole factor affecting the OS index at T2 (t = 2.843, p = 0.006). Conclusion: In our study, we observed elevated OS values and relatively low rSO2 values during on-pump CABG procedures, with rSO2 showing an association with increased OS parameters. Close monitoring of the OS response level and rSO2 during CABG could potentially enhance postoperative clinical outcomes.

Comparison of outcomes between off-pump and on-pump coronary artery bypass graft surgery using collaborative targeted maximum likelihood estimation.

There are some discrepancies about the superiority of the off-pump coronary artery bypass grafting (CABG) surgery over the conventional cardiopulmonary bypass (on-pump). The aim of this study was estimating risk ratio of mortality in the off-pump coronary bypass compared with the on-pump using a causal model known as collaborative targeted maximum likelihood estimation (C-TMLE). The data of the Tehran Heart Cohort study from 2007 to 2020 was used. A collaborative targeted maximum likelihood estimation and targeted maximum likelihood estimation, and propensity score (PS) adjustment methods were used to estimate causal risk ratio adjusting for the minimum sufficient set of confounders, and the results were compared. Among 24,883 participants (73.6% male), 5566 patients died during an average of 8.2 years of follow-up. The risk ratio estimates (95% confidence intervals) by unadjusted log-binomial regression model, PS adjustment, TMLE, and C-TMLE methods were 0.86 (0.78-0.95), 0.88 (0.80-0.97), 0.88 (0.80-0.97), and 0.87(0.85-0.89), respectively. This study provides evidence for a protective effect of off-pump surgery on mortality risk for up to 8 years in diabetic and non-diabetic patients.

Self-Practice Program for Beating-Heart Minimally Invasive Coronary Anastomosis Using a Homemade Low-Fidelity Simulator: A Proof of Concept.

OBJECTIVE: We evaluated the effectiveness of a consistent and structured self-practice coronary anastomosis program using a homemade low-fidelity beating-heart simulator. METHODS: An intermediary trainee was subjected to an 8-week structured self-practice program. The program was divided into 2 parts of nonbeating and beating practices with a minimum number of timed anastomoses. Each part was followed by an assessment using an objective skills assessment tool score. The beating-heart simulator was built using motorized toy blocks connected wirelessly to a smartphone application. This was coded to enable rate selection. A junior consultant was compared to the subject at the end of the program. Both were tasked to perform 1 coronary anastomosis for both off-pump coronary artery bypass (OPCAB) and minimally invasive CAB (MICS) setup. The primary outcomes were anastomotic time and score compared with the junior consultant. Secondary outcomes were progression of anastomotic time and score throughout the program. RESULTS: Overall performance of the studied subject approached the performance of the junior consultant in terms of time (OPCAB, 489 vs 605 s; MICS, 712 vs 652 s) and scores (OPCAB, 21 vs 20.7; MICS, 19 vs 20.6). There were inverse correlations between anastomosis time and number of practices for both nonbeating and beating anastomoses. Overall improvement was observed in terms of assessment scoring by 26.6%. CONCLUSIONS: A structured self-practice program using an affordable and accessible simulator was able to help trainees overcome the MICS anastomosis learning curve quicker when introduced earlier. This may encourage earlier adoption of MICS among surgeons.

Antithrombotic drug removal with hemoadsorption during off-pump coronary artery bypass grafting.

BACKGROUND: Patients requiring coronary artery bypass grafting (CABG) are often loaded with antithrombotic drugs (AT) and are at an increased risk for perioperative bleeding complications. Active AT removal by a hemoadsorption cartridge integrated in the cardiopulmonary bypass circuit is increasingly used in this setting to reduce bleeding, and herein we describe the extension of this application in patients on AT undergoing off-pump coronary artery bypass (OPCAB). METHODS: Ten patients (80% male; mean age: 67.4 ± 9.2years) were treated with ticagrelor (eight patients), rivaroxaban and ticagrelor (one patient), and rivaroxaban (one patient) prior to OPCAB surgery. AT's were discontinued one day before surgery in nine patients and on the day of surgery in one patient, and all patients were also on aspirin. The cohort mean EuroSCORE-II was 2.9 ± 1.5%. A hemoadsorption cartridge was integrated into a dialysis device (n=4) or a stand-alone apheresis pump (n=6) periprocedural, for a treatment time of 145 ± 33 min. Outcome measures included bleeding according to Bleeding Academic Research Consortium (BARC)-4 and 24-hour chest-tube-drainage (CTD). RESULTS: Mean operation time was 184 ± 35 min. All patients received a left internal thoracic artery with a mean of 2.3 ± 0.9 total grafts. One patient had a BARC-4 bleeding event and there were no surgical re-explorations for bleeding. Mean 24-hours CTD was 680 ± 307mL. During follow-up of 19.5 ± 17.0 months, none of the patients died or required further reinterventions. No device-related adverse events were reported. CONCLUSIONS: Hemoadsorption via a stand-alone apheresis pump during OPCAB surgery was feasible and safe. This innovative and new approach showed favorable bleeding rates in patients on antithrombotic drugs requiring bypass surgery.

Surgical Coronary Revascularization in Patients With Underlying Atrial Fibrillation: State-of-the-Art Review.

The number of individuals referred for coronary artery bypass grafting (CABG) with preoperative atrial fibrillation (AF) is reported to be 8% to 20%. Atrial fibrillation is a known marker of high-risk patients as it was repeatedly found to negatively influence survival. Therefore, when performing surgical revascularization, consideration should be given to the concomitant treatment of the arrhythmia, the clinical consequences of the arrhythmia itself, and the selection of adequate surgical techniques. This state-of-the-art review aimed to provide a comprehensive analysis of the current understanding of, advancements in, and optimal strategies for CABG in patients with underlying AF. The following topics are considered: stroke prevention, prophylaxis and occurrence of postoperative AF, the role of surgical ablation and left atrial appendage occlusion, and an on-pump vs off-pump strategy. Multiple acute complications can occur in patients with preexisting AF undergoing CABG, each of which can have a significant effect on patient outcomes. Long-term results in these patients and the future perspectives of this scientific area were also addressed. Preoperative arrhythmia should always be considered for surgical ablation because such an approach improves prognosis without increasing perioperative risk. While planning a revascularization strategy, it should be noted that although off-pump coronary artery bypass provides better short-term outcomes, conventional on-pump approach may be beneficial at long-term follow-up. By collecting the current evidence, addressing knowledge gaps, and offering practical recommendations, this state-of-the-art review serves as a valuable resource for clinicians involved in the management of patients with AF undergoing CABG, ultimately contributing to improved outcomes and enhanced patient care.

10-Year Mortality of Off-Pump Versus On-Pump Coronary Artery Bypass Grafting: An Updated Systematic Review, Meta-Analysis, and Meta-Regression.

The longstanding debate on off-pump coronary artery bypass grafting (OPCAB) versus on-pump coronary artery bypass grafting (ONCAB) has primarily focused on short-term and mid-term outcomes, with limited attention to long-term survival. This study aims to address this gap by providing an updated analysis of 10-year mortality rates after OPCAB versus ONCAB. We have conducted a systematic review and meta-analysis, incorporating 22 studies comprising 69,449 patients. The primary end point was all-cause mortality at 10 years. Meta-regression analysis explored sources of heterogeneity. The meta-analysis revealed no significant difference in long-term all-cause mortality between OPCAB and ONCAB (hazard ratio 1.000, 95% confidence interval 0.92 to 1.08, p = 0.95). Although substantial heterogeneity existed across studies, meta-regression identified older age as a significant factor favoring OPCAB. However, patient characteristics like gender, co-morbidities, and graft numbers did not significantly influence the choice of surgical technique. In conclusion, this study challenges historical concerns regarding OPCAB's quality of revascularization and long-term survival demonstrating comparable outcomes to ONCAB in well-selected patients when performed by experienced surgeons. The results emphasize the importance of surgeon proficiency and advocate for recognizing surgical revascularization as a subspecialty.

Off-Pump Coronary Artery Bypass Grafting Does Not Confer Superior Outcomes Among Frail Patients.

Off-pump coronary revascularization (OPCAB) has been proposed to benefit patients who are at a greater surgical risk because it avoids the use of extracorporeal circulation. Although, historically, older patients were considered high-risk candidates, recent studies implicate frailty as a more comprehensive measure of perioperative fitness. Yet, the outcomes of OPCAB in frail patients have not been elucidated. Thus, using a national cohort of frail patients, we assessed the impact of OPCAB relative to on-pump coronary revascularization (ONCAB). Patients who underwent first-time elective coronary revascularization were tabulated from the 2010 to 2020 Nationwide Readmissions Database. Frailty was assessed using the previously-validated Johns Hopkins Adjusted Clinical Groups indicator. Multivariable models were used to consider the independent associations between OPCAB and the key outcomes. Of ∼26,529 frail patients, 6,322 (23.8%) underwent OPCAB. After risk adjustment and compared with ONCAB, OPCAB was linked with similar odds of in-hospital mortality but greater likelihood of postoperative cardiac arrest (adjusted odds ratio [AOR] 1.53, confidence interval [CI] 1.13 to 2.07) and myocardial infarction (AOR 1.44, CI 1.23 to 1.69). OPCAB was further associated with greater odds of postoperative infection (AOR 1.22, CI 1.02 to 1.47) but decreased need for blood transfusion (AOR 0.68, CI 0.60 to 0.77). In addition, OPCAB faced a +0.86-day increase in length of stay (CI 0.21 to 1.51) but similar costs (ß $1,610, CI -$1,240 to 4,460) relative to ONCAB. Although OPCAB was associated with no difference in mortality compared with ONCAB, it was linked with greater likelihood of postoperative cardiac arrest and myocardial infarction. Our findings demonstrate that ONCAB remains associated with superior outcomes, even in the growing population of frail patients who underwent coronary revascularization.

Prospective Randomized Pilot Trial on the Effects of Mild Hypercapnia on Cerebral Oxygen Saturation in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting.

OBJECTIVE AND DESIGN: A single-center prospective randomized controlled study was conducted to assess the effect of targeted mild hypercapnia (TMH) on cerebral oxygen saturation (rSO2) in patients undergoing off-pump coronary artery bypass grafting (CABG). SETTING AND PARTICIPANTS: A prospective randomized controlled study involving 100 patients undergoing off-pump CABG at U. N. Mehta Hospital, Ahmedabad, Gujarat, India. INTERVENTION: Patients were randomized to either the TMH (PaCO2 45-55 mmHg) or the targeted normocapnia (TN; PaCO2 35-45 mmHg) group, containing 50 patients in each group. MEASUREMENTS: Monitoring of rSO2, heart rate, mean arterial pressure (MAP), PaCO2, and peripheral oxygen saturation was done at baseline, after induction, after left internal mammary artery harvesting, at each grafting (distal and proximal), after protamine, and after shifting to the intensive care unit. The standardized minimental-state examination (SMMSE) was performed preoperatively and at 8, 12, and 24 hours postextubation. Data were analyzed using an independent sample t test. RESULTS: The TMH group had higher MAP during grafting (p < 0.001) and higher rSO2 on both sides during distal and proximal grafting (p < 0.001) and after protamine (p < 0.05), as compared to the TN group. Compared to preoperative values, SMMSE scores in the TN group were significantly lower at 12 and 24 hours postextubation (p < 0.001). CONCLUSION: TMH during grafting increased the cerebral blood flow and rSO2 when hemodynamic instability was very common. It has a protective role on the brain and helps maintain cognition postoperatively.

Off-pump versus on-pump coronary artery bypass grafting in elderly patients at 30 days: a propensity score matching study.

BACKGROUND: Elderly patients are at increased risk of perioperative morbidity and mortality after conventional on-pump coronary artery bypass grafting (ONCABG). This study was to determine whether such high-risk population would benefit from off-pump coronary artery bypass grafting (OPCABG). METHODS: A retrospective analysis was performed on patients aged 65 years or older who underwent isolated coronary artery bypass grafting for the first time in Wuhan Union Hospital from January 2015 to January 2021. We used propensity score matching to adjust for differences in baseline characteristics between the ONCABG and OPCABG groups. Morbidity and mortality within 30 days after surgery were compared between the two groups. All operations were performed by experienced cardiac surgeons. RESULTS: A total of 511 patients (ONCABG 202, OPCABG 309) were included. After 1:1 matching, the baseline characteristics of the two groups were comparable (ONCABG 173, OPCABG 173). The OPCABG group had higher rate of incomplete revascularization (13.9% vs. 6.9%; P = .035) than the ONCABG group. However, OPCABG reduced the risk of postoperative renal insufficiency (15.0% vs. 30.1%; P = .001) and reoperation for bleeding (0.0% vs. 3.5%; P = .030). There were no significant differences in early postoperative mortality, myocardial infarction, stroke, and other outcomes between the two groups. CONCLUSIONS: OPCABG is an alternative revascularization method for elderly patients. It reduces the risk of early postoperative renal insufficiency and reoperation for bleeding.

The effect of body mass index on short-term outcomes in patients undergoing off-pump coronary artery bypass grafting surgery: a retrospective study from a single cardiovascular center.

OBJECTIVE: This study is designed to investigate the impact of body mass index (BMI) on the short-term outcomes of patients undergoing off-pump coronary artery bypass graft (OPCAB) surgery. METHODS: Data was obtained from 1006 Chinese patients who underwent isolated, primary OPCAB at a high-traffic cardiovascular center during 2020. Subjects were categorized, by BMI, into a low & normal weight (LN) group (BMI < 24 kg/m2), an overweight (OVW) group (24 ≤ BMI < 28 kg/m2), and an obese (OBS) group (BMI ≥ 28 kg/m2). Information pertaining to patients' short-term outcomes (including incidence of mortality and morbidities; duration of postoperative mechanical ventilation; length of stay in the ICU and hospital; postoperative bleeding; etc.) were extracted, and the data from each group were compared. RESULTS: The incidences of in-hospital mortality and morbidities were similar for all three groups. The volume of fluid infusion, postoperative bleeding within 24 h and total bleeding in LN group were higher than those in the OBS group (P < 0.001). The hemoglobin level was lower in the LN group than that in the OBS group (P < 0.001). Duration of mechanical ventilation and length of stay in the ICU in the LN group were longer than those in the OBS group (P < 0.001). CONCLUSIONS: Our results demonstrate that BMI is not significantly related with short-term outcomes in OPCAB patients. However, we suggest that OPCAB patients with low-normal BMI are more susceptible to post-operative blood loss.

The Effects of Daytime Variation on Short-term Outcomes of Patients Undergoing Off-Pump Coronary Artery Bypass Grafting.

OBJECTIVE: To evaluate the effects of time of surgery on the short-term outcomes of patients undergoing off-pump coronary artery bypass grafting (OPCABG). DESIGN: A retrospective cohort study. SETTING: A single large-volume cardiovascular center. PATIENTS: Patients undergoing elective OPCABG between September 2019 and July 2022. INTERVENTIONS: Patients were divided into the following 2 groups according to the start time of surgery: morning (AM group, before 11 AM) and afternoon (PM group, after 11 AM). Propensity-score matching (PSM) with a 1:1 matching ratio was used to create comparable cohorts. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was the composite incidence of mortality and morbidities during hospitalization. Secondary endpoints included postoperative bleeding and transfusion, mechanical ventilation duration (MVD), and lengths of stay (LOS) in the intensive care unit (ICU) and hospital. From a consecutive series of 1,039 patients, PSM yielded 317 well-matched pairs. There was no difference in the composite incidence of in-hospital mortality and morbidities between the AM and PM groups (16.4% v 17.4%, p = 0.832). However, patients in the PM group were associated with less postoperative blood loss over the first 24 hours (470 v 540 mL, p = 0.002), decreased MVD (14 v 16 hours, p < 0.001), and shorter LOS in ICU (46 v 68 hours, p = 0.002) compared to patients in AM group. CONCLUSIONS: The current study suggested a lack of relevance regarding the time of surgery with in-hospital mortality and morbidities in patients undergoing OPCABG.

Nomogram for predicting major bleeding after off-pump coronary artery bypass grafting.

OBJECTIVE: The purpose of this investigation is to develop a novel nomogram for predicting major bleeding following off-pump coronary artery bypass grafting (CABG). METHODS: Between January 2012 and December 2022, 541 patients who underwent off-pump isolated primary CABG were included in a retrospective analysis. The primary outcome measure after off-pump CABG was major bleeding. Based on the outcomes of a multivariate analysis, nomograms were constructed. Using receiver operating characteristic analysis and calibration, the predictive accuracy of the nomograms was assessed. Using decision curve analysis (DCA), the clinical benefit of the nomograms was determined. RESULTS: We categorized 399 and 142 patients in the "no major bleeding group" and "major bleeding group", respectively. Age (odds ratio (OR) 1.038; 95% confidence interval (CI) 1.009-1.068; p = 0.009), body mass index (OR 0.913; 95% CI 0.849-0.982; p = 0.014), hemoglobin (OR 0.958; 95% CI 0.945-0.971; p < 0.001), sodium (OR 0.873; 95% CI 0.807-0.945; p = 0.001), blood urea nitrogen (OR 1.198; 95% CI 1.073-1.338; p = 0.001), and operation time (OR 1.012; 95% CI 1.008-1.017; p < 0.001) were independent predictors for major bleeding after off-pump CABG. The model based on independent predictors exhibited excellent discrimination and calibration, with good agreement between actual and nomogram-estimated probabilities of generalization. DCA demonstrated that nomogram-assisted decisions have a greater positive benefit than treating all patients or none. CONCLUSIONS: The plotted nomogram accurately predicted major bleeding outcomes following off-pump CABG and may therefore contribute to clinical decision-making, patient treatment, and consultation services.

Time course changes in insulin sensitivity during cardiac surgery: A retrospective study on intraoperative glycemic management using an artificial pancreas.

INTRODUCTION: Glycemic control is essential for improving the prognosis of cardiac surgery, although precise recommendations have not yet been established. Under a constant blood glucose level, the insulin infusion rate correlates with insulin resistance during glycemic control using an artificial pancreas (AP). We conducted this retrospective study to elucidate changes in intraoperative insulin sensitivity as a first step to creating glycemic control guidelines. METHODS: Fifty-five cardiac surgery patients at our hospital who underwent intraoperative glycemic control using an AP were enrolled. Twenty-three patients undergoing surgical procedures requiring cardiac arrest under hypothermic cardiopulmonary bypass (CPB) with minimum rectal temperatures lower than 32°C, 13 patients undergoing surgical procedures requiring cardiac arrest under hypothermic CPB with minimum rectal temperatures of 32°C, eight patients undergoing on-pump beating coronary artery bypass grafting and 11 patients undergoing off-pump coronary artery bypass were assigned to groups A, B, C and D, respectively. We analyzed the time course of changes in the data derived from glycemic control using the AP. RESULTS: Significant time course changes were observed in groups A and B, but not in groups C and D. Insulin resistance was induced after the start of hypothermic CPB in groups A and B, and the induced change was not resolved by the rewarming procedure, remaining sustained until the end of surgery. CONCLUSIONS: Hypothermia is the predominant factor of the induced insulin resistance during cardiac surgery. Thus, careful glycemic management during hypothermic CPB is important. Prospective clinical studies are required to confirm the findings of this study.

The aortic knob index as a novel predictor of new-onset atrial fibrillation after off-pump coronary artery bypass grafting.

PURPOSE: To validate the predictive value of the aortic knob index for identifying new-onset postoperative atrial fibrillation (POAF) after off-pump coronary artery bypass grafting (OPCAB). METHODS: Among 156 patients who underwent isolated OPCAB, 138 consecutive patients without a history of atrial fibrillation were enrolled in this retrospective observational cohort study. The patients were divided into two groups based on the development of POAF. We compared the baseline clinical characteristics; preoperative radiographic characteristics of the aorta, including aortic knob measurements; and perioperative data, between the groups. Logistic regression analysis was performed to identify the predictors of new-onset POAF. RESULTS: New-onset POAF developed in 35 (25.4%) patients. Multivariate logistic regression analysis revealed that the aortic knob index was an independent predictor of POAF and yielded that the risk of POAF increased by 1.85 times when the aortic knob index increased by 0.1 (odds ratio, 1.853; confidence interval, 1.326-2.588; P < 0.001). Receiver operating characteristic analysis revealed that an aortic knob index of 1.364 constituted a cutoff value for new-onset POAF with 80.0% sensitivity and 65.0% specificity. CONCLUSIONS: The aortic knob index on preoperative chest radiography was a significant and independent predictor of new-onset POAF following OPCAB.

Less Invasive and Hybrid Surgical/Interventional Coronary Disease Management: The Future Is Now.

Coronary artery bypass grafting (CABG) has evolved to become the criterion standard in elective revascularisation for coronary artery disease (CAD), particularly in patients with complex or multivessel CAD, left main involvement, diabetes mellitus, or left ventricular dysfunction. Despite the superiority of CABG in patients with the most advanced forms of CAD, a standard CABG operation, through a median sternotomy and with the use of cardiopulmonary bypass, carries well recognised challenges. In this article, we describe newer approaches, such as off-pump CABG, minimally invasive bypass grafting, robotic CABG, and hybrid coronary revascularisation, which we consider as necessary ways to minimise invasion, reduce recovery time, provide the benefits of arterial grafting to more patients, and offer alternatives to mitigate the adverse effects of conventional sternotomy and cardiopulmonary bypass.

Continuous cardiac output estimation using a new modified Fick method during off-pump coronary artery bypass graft surgery: a retrospective observational study.

PURPOSE: Several technical aspects of the Fick method limit its use intraoperatively. A data-driven modification of the Fick method may enable its use in intraoperative settings. METHODS: This two-center retrospective observational study included 57 (28 and 29 in each center) patients who underwent off-pump coronary artery bypass graft (OPCAB) surgery. Intraoperative recordings of physiological data were obtained and divided into training and test datasets. The Fick equation was used to calculate cardiac output (CO-Fick) using ventilator-determined variables, intraoperative hemoglobin level, and SvO2, with continuous thermodilution cardiac output (CCO) used as a reference. A modification CO-Fick was derived and validated: CO-Fick-AD, which adjusts the denominator of the original equation. RESULTS: Increased deviation between CO-Fick and CCO was observed when oxygen extraction was low. The root mean square error of CO-Fick was decreased from 6.07 L/min to 0.70 L/min after the modification. CO-Fick-AD showed a mean bias of 0.17 (95% CI 0.00-0.34) L/min, with a 36.4% (95% CI 30.6-44.4%) error. The concordance rates of CO-Fick-AD ranged from 73.3 to 87.1% depending on the time interval and exclusion zone. CONCLUSIONS: The original Fick method is not reliable when oxygen extraction is low, but a modification using data-driven approach could enable continuous estimation of cardiac output during the dynamic intraoperative period with minimal bias. However, further improvements in precision and trending ability are needed.