Short-term outcomes of on- vs off-pump coronary artery bypass grafting in patients with left ventricular dysfunction: a systematic review and meta-analysis

Two novel nomograms predict 30-day mortality after off-pump coronary artery bypass grafting

Background

With the development of surgical techniques and medical equipment, the mortality rate of off-pump coronary artery bypass grafting (CABG) has been declining year by year, but there is a lack of convenient and accurate predictive models. This study aims to use two nomograms to predict 30-day mortality after off-pump CABG.

Methods

Patients with isolated off-pump CABG from January 2016 to January 2021 were consecutively enrolled. Potential predictive factors were first screened by lasso regression, and then predictive models were constructed by multivariate logistic regression. To earlier identify high-risk patients, two nomograms were constructed for predicting mortality risk before and after surgery.

Results

A total of 1840 patients met the inclusion and exclusion criteria. The 30-day mortality was 3.97 % (73/1840) in this cohort. Multivariate logistic analysis showed that age, BMI<18.5 kg/m2, surgical time, creatinine, LVEF, history of previous stroke, and major adverse intraoperative events (including conversion to cardiopulmonary bypass or implantation of intra-aortic balloon pump) were independently associated with 30-day mortality. Model 1 contained preoperative and intraoperative variables, and the AUC was 0.836 (p < 0.001). The AUC of the K-fold validation was 0.819. Model 2 was only constructed by preoperative information. The AUC was 0.745 (p < 0.001). The AUC of the K-fold validation was 0.729. The predictive power of Model 1 was significantly higher than the SinoScore (DeLong's test p < 0.001).

Conclusions

The two novel nomograms could be conveniently and accurately used to predict the risk of 30-day mortality after isolated off-pump CABG.

Is Single LIMA-LAD Bypass Appropriate for OPCAB Training?

BACKGROUND

 A significant impact of surgeons' experience on outcomes of off-pump coronary artery bypass (OPCAB) has been recognized through previous large-scale studies. However, a safe, effective, and concrete OPCAB training was yet to be identified. We evaluate a safety of our OPCAB training model with single left internal mammary artery (LIMA)-left anterior descending artery (LAD) as a reasonable first step.

METHODS

 Between January 2010 and June 2019, 180 patients with an isolated single coronary bypass of the LAD using LIMA as an in situ graft via median sternotomy fulfilled the inclusion criteria. Coronary arterial bypass under cardiopulmonary bypass (CPB), utilizing other graft material, minimal invasive direct coronary arterial bypass through left-sided thoracotomy, and multiple diseased coronary artery disease were excluded. The primary outcome is an early postoperative outcome (major adverse cardiac and cerebrovascular events [MACCEs]: myocardial infarction, coronary re-revascularization, stroke, acute renal failure, and all causes of death) between residents in training under supervision (group 1: n = 63) and experienced surgeons (group 2: n = 117). Trainees were already experienced in on-pump coronary artery bypass grafting.

RESULTS

 Preoperative variables were comparable. There was no significant difference in the rate of MACCEs between the two groups including hospital mortality (p = 1.000), perioperative myocardial infarction (p = 0.246), stroke (p = 0.655), and acute renal failure (p = 0.175).

CONCLUSION

 The early postoperative outcome of off-pump LIMA to the LAD performed by trainees was comparable to those by experienced surgeons. Single LIMA-LAD was safely performed by trainees under supervision without CPB. In order to master OPCAB technique, single LAD bypass might be a reasonable first step to get into touch with the technical characteristics of this special procedure.

Coronary artery bypass grafting in left ventricular dysfunction: when and how

PURPOSE OF REVIEW

The surgical management of patients undergoing coronary artery bypass grafting (CABG) with low ejection fraction presents unique challenges that require meticulous attention to details and good surgical technique and judgement. This review details the latest evidence and best practices in the care of such patients.

RECENT FINDINGS

CABG in patients with low ejection fraction carries a significant risk of perioperative mortality and morbidity related to the development of postcardiotomy shock. Preoperative optimization with pharmacological or mechanical support is required, especially in patients with cardiogenic shock. Rapid and complete revascularization is what CABG surgeons aim to achieve. Multiple arterial revascularization should be reserved to selected patients. Off-pump CABG, on-pump breathing heart CABG, and new cardioplegic solutions remain of uncertain benefit compared with traditional CABG.

SUMMARY

Tremendous advancements in CABG allowed surgeons to offer revascularization to patients with severe left ventricular dysfunction and multivessel disease with acceptable risk. Despite that, there is a lack of comprehensive and robust studies particularly on long-term outcomes. Individualized patient assessment and a heart team approach should be used to determine the optimal surgical strategy for each patient.

Propensity score analysis comparing off-pump versus on-pump coronary artery bypass grafting in older adults

OBJECTIVE

This study aimed to compare the results of off-pump and on-pump coronary artery bypass grafting in older adults and to examine early and late outcomes.

METHODS

This study included 226 patients aged ≥ 75 years who underwent isolated coronary artery bypass grafting. Of these, 141 and 85 patients were included in the off-pump and on-pump groups, respectively. Propensity scores were calculated for each case, matched, and compared between the two groups (68 cases in each group), along with mid-term outcomes of survival and major adverse cardiac events.

RESULTS

Operative time, red blood cell transfusion volume, and postoperative hospital stay duration were significantly higher in the on-pump group (267 vs 370 min, P < 0.001; 4.3 vs 17.2 units, P < 0.001; and 20.8 vs 35.8 days, P = 0.012, respectively). Postoperative occurrence of new atrial fibrillation was significantly higher in the on-pump group (4.4% vs 27.9%, P < 0.001), and Kaplan-Meier survival analysis showed a significantly worse prognosis in the on-pump group than in the off-pump group (3-year survival rate 90.7% vs 71.5%, log rank P = 0.007). However, there was no statistically significant difference in cardiovascular-related deaths (log rank P = 0.07).

CONCLUSIONS

On-pump coronary artery bypass grafting in an older adult population resulted in increased transfusion volume and postoperative occurrence of atrial fibrillation. The mid-term postoperative outcomes were also poorer with on-pump coronary artery bypass grafting. Off-pump coronary artery bypass grafting reduced future all-cause deaths in older adults.

Blood Products Utilization Status in Off-Pump Cardiac Surgery Patients

Background: Transfusion support has an essential role in coronary artery bypass graft (CABG). The time-honored gold standard for CABG is the on-pump procedure (ONCAB); however, off-pump coronary artery bypass (OPCAB) is also a safe, cost-benefit procedure with fewer blood transfusion requirements. This study was performed to evaluate transfusion patterns in OPCAB due to the diversity of transfusion practices. Materials and Methods: This retrospective study was performed to determine the transfusion rate and triggers in OPCAB patients. Medical files of all patients undergoing OPCAB surgery at Sanandaj Tohid Hospital in 2014 were reviewed. Patients' demographics data, preoperative laboratory tests (PT, aPTT, Hb, Hct, Platelet count), underlying medical conditions, and their possible relation to further transfusions and the ward department in which the transfusion had taken place were extracted. SPSS 16 Chicago software, T-student Test, One Way Anova, and χ2 exam were applied for data analysis. P values ≤0.05was considered significant. Results: Among 91 elective OPCAB patients: 28(30.8%) women and 63(69.2%) men with mean age of 64.80±9.02 years, 63(69.23%) received a blood product. Mean utilization of PRBC, FFP, Platelet, and Cryoprecipitate were 2.17±2.044, 2.46±2.86, 2.86±3.80 and 0.40±2.10 units, respectively. ICU revealed the highest consumption rate for all products.  Female sex (p<0.001), Hypertension (P=0.002), and low hemoglobin(P=0.004) were noted as predictive factors for transfusion.  Conclusion: This study concluded that the transfusion rate in OPCAB is still very high in Iran (regarding a study in a countryside hospital) and that the highest utilization rate is seen in the ICU.

Impact of Ticagrelor Versus Clopidogrel on Bleeding Outcomes of Isolated Coronary Artery Bypass Grafting

BACKGROUND

Increased bleeding risks have been documented in patients exposed to P2Y₁₂ inhibitors within 5 days of coronary artery bypass surgery (CABG). This study aimed to determine the relative CABG bleeding risks of clopidogrel versus ticagrelor exposure and the proper time course of ticagrelor discontinuation prior to surgery.

METHODS

Clinical outcomes were assessed in 2075 isolated CABG patients, including 375 who had received P2Y₁₂ inhibitors within 5 days of surgery (155 clopidogrel, 213 ticagrelor, 7 prasugrel). BARC-4 CABG bleeding complications and perioperative blood product usage were assessed in propensity-matched P2Y₁₂-inhibited and non-P2Y₁₂-inhibited cohorts.

RESULTS

P2Y₁₂-inhibited patients (n = 375) in comparison to matched non-P2Y₁₂-inhibited patients (n = 1138) had higher rates of re-operation for bleeding (3.8 % vs 1.3 %, p = 0.003), postoperative red blood cell transfusion ≥5 units (5.7 % vs 2.7 %, p = 0.007), and intraoperative and postoperative blood product utilization (42.3 % vs 27.1 %, p < 0.001; 41.8 % vs 32.2 %, p < 0.001, respectively). Univariate predictors of BARC-4 bleeding included clopidogrel (OR: 2.145, 95 % CI: 1.131-4.067, p = 0.019) and ticagrelor discontinued within 3 days of surgery (OR: 2.153, 95 % CI: 1.003-4.169, p = 0.049). Multivariate logistic regression demonstrated that only clopidogrel exposure was an independent BARC-4 bleeding predictor (OR: 1.850, 95 % CI: 1.007-3.398, p = 0.048). Unadjusted ticagrelor patients with drug discontinuation 4-5 days prior to CABG only demonstrated higher rates of perioperative platelet transfusion, without additional signs of excessive bleeding.

CONCLUSIONS

Clopidogrel exposure within 5 days of CABG is an independent predictor of BARC-4 bleeding, whereas major ticagrelor bleeding effects are confined to drug exposure within 3 days of surgery.

Off-pump versus on-pump coronary artery bypass graft surgery outcomes in patients with severe left ventricle dysfunction: inverse probability weighted study

Objective

In this study we aimed to compare on-pump and off-pump coronary artery bypass grafting (CABG) outcomes in patients presented with low left ventricular ejection fraction (EF) as a high-risk group of patients.

Methods

In this registry-based study from 2014 and 2016, all patients with severe left ventricular dysfunction (EF less than 35%) were included and followed until 2020. The median follow-up period was 47.83 [38.41, 55.19] months. Off pump CABG (OPCABG) was compared with on-pump CABG (ONCABG) in terms of mid-term non-fatal cardiovascular events (CVEs) and all-cause mortality. Propensity score method (with inverse probability weighting technique) was used to compare these two groups.

Results

From 14,237 patients who underwent isolated CABG, 2055 patients with EF ≤ 35% were included; 1705 in ONCABG and 350 patients in OPCABG groups. Although OPCABG was associated with lower risk of 30-days mortality (Odds Ratio [OR]: 0.021; Confidence Interval [CI] 95% [0.01, 0.05], P < 0.001); there was no significant difference between OPCABG and ONCABG in term of mid-term mortality and non-fatal CVEs ((Hazard ratio [HR]: 0.822; 95%CI [0.605, 1.112], p = 0.208) and (HR: 1.246; 95%CI [0.805, 1.929], p = 0.324), respectively). Patients with more than three traditional coronary artery disease risk factors, had more favorable outcomes (in terms of mid-term mortality) if underwent OPCABG (HR: 0.420; 95%CI [0.178, 0.992], p = 0.048).

Conclusion

OPCABG was associated with lower risk of 30-days mortality; however, mid-term outcomes were comparable in both OPCABG and ONCABG techniques.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02895-0.

Induced blood oxidation in myocardial revascularization

Background: The use of artificial circulation in surgical myocardial revascularization is one of the key pathogenetic factors in the development of the oxidative stress and systemic inflammatory response in the postoperative period. Aims: the purpose of the study was to describe the dynamics of the induced blood oxidation parameters during coronary artery bypass surgery in the conditions of artificial circulation and on the working heart. Methods: The study included 64 patients who underwent coronary bypass surgery, with 31 (48.4%) on-pump patients and 33 (51.6%) off-pump patients. The oxidative stress simulations were conducted under the in vitro conditions. The blood oxidation-induced values were studied using a biological oxygen monitor. Results: In patients with coronary heart disease, regardless of the choice of the revascularization method (on-pump / off-pump), we observed statistically significantly (p 0.05) higher initial and maximum blood oxidation rates, the oxidative activity factor, and a shorter initiation period than those in healthy volunteers. No significant differences were found by the inter-group comparison analysis both 10 days and 6 months post-surgery. Conclusion: The indicators of induced blood oxidation do not depend on the method of revascularization during coronary bypass grafting (artificial circulation or a working heart). The changes in the parameters indicating activation of the oxidative and antioxidant blood systems may be transient by their nature and occur in the early postoperative period.

Post-Coronary Artery Bypass Grafting Cognitive Decline: Risk Modification And Implications For Screening In Low-Risk Population

Background — Postoperative cognitive dysfunction (POCD) is an important complication of coronary artery bypass grafting (CABG). Large amount of data points to the problem of POCD in patients with high surgical risk of CABG. Low-risk patients are not safe from these complications either. Assessment of the severity, duration of POCD, degree of recovery and risk factors in off- and on-pump patients with stable coronary artery disease is crucial in minimization of the POCD risk in patients with low surgical risk. Objective — to analyze incidence, severity, reversibility and risk factors of POCD in patients undergoing elective low-risk CABG. Methods and Results — The retrospective cohort study included 79 patients who underwent on-pump (N=44) or off-pump (N=35) elective CABG with low surgical risk (mean EuroSCORE II death risk 1.08±0.71%), with observation period of 6 months. Pre-CABG markers of cognitive impairment were found in 50% of patients, with 44% of patients demonstrating POCD. Patients who underwent off-pump CABG demonstrated more pronounced decline in MoCA score compared to on-pump (-3.9±2.0 vs. -2.2±2.0 at 8 days point, p=0.018), with regress to pre-CABG results after 3 weeks. Baseline MoCA score <25 was found to be a predictor for more pronounced cognitive decline at 8 days point. MMSE demonstrated less predictive value compared to MoCA. Conclusion — POCD risk differs in off-pump and on-pump CABG cohorts, with significantly higher prevalence in the former group, whether assessed using MMSE or MoCA tests. Differences are observed within 3 weeks post-CABG. Pre-CABG MoCA score <25 is associated with more pronounced POCD in low-risk elective CABG cohort.

A Comparison of Patients Undergoing On- vs. Off-Pump Coronary Artery Bypass Surgery Managed with a Fast-Track Protocol

The purpose of this study was to compare patients who underwent on- vs. off-pump coronary artery bypass surgery managed with a fast-track protocol. Between September 2012 and December 2018, n = 3505 coronary artery bypass surgeries were managed with a fast-track protocol in our specialized post-anesthesia care unit. Propensity score matching was applied and resulted in two equal groups of n = 926. There was no significant difference in ventilation time (on-pump 75 (55-120) min vs. off-pump 80 (55-120) min, p = 0.973). We found no statistically significant difference in primary fast-track failure in on-pump (8.2% (76)) vs. off-pump (6% (56)) groups (p = 0.702). The secondary fast-track failure rate was comparable (on-pump 12.9% (110) vs. off-pump 12.3% (107), p = 0.702). There were no significant differences between groups in regard to the post-anesthesia care unit, the intermediate care unit, and the hospital length of stay. Postoperative outcome and complications were also comparable, except for a statistically significant difference in PACU postoperative blood loss in on-pump (234 mL) vs. off-pump (323 mL, p < 0.0001) and red blood cell transfusion (11%) and (5%, p < 0.001), respectively. Our results suggest that on- and off-pump coronary artery bypass surgery in fast-track settings are comparable in terms of ventilation time, fast-track failure rate, and postoperative complications rate.

Coronary artery bypass grafting under sole Impella 5.0 support for patients with severely depressed left ventricular function

Selection of the ideal surgical procedure for coronary revascularization in patients with severe cardiac dysfunction at times may represent a challenge. In recent years, with the advent of surgical large microaxial pumps, e.g., Impella 5.0 (Abiomed Inc., Boston, USA), specific support and effective unloading of the left ventricle has become available. In the interventional field, good results have been achieved with smaller microaxial pumps in the setting of so-called protected percutaneous coronary intervention. In this study, we would like to share our early experience with surgical coronary revascularization under the sole support of Impella 5.0, omitting the use of heart–lung machine in three cases of severe cardiac dysfunction due to complex ischemic heart disease. Effective circulatory support intraoperatively and postoperatively speaks in favor of this technique in selected patients.