Early and mid-term impacts of cardiopulmonary bypass on coronary artery bypass grafting in patients with poor left ventricular dysfunction: a propensity score analysis

Off-pump coronary artery bypass grafting is safe and effective in patients with severe left ventricular dysfunction

OBJECTIVES

Severe left ventricular dysfunction (LVD) is associated with increased risk following coronary artery bypass grafting (CABG). Due to a dearth of reports on the choice of CABG technique in patients with LVD, this study aims to compare the outcomes of off-pump CABG (OPCAB) and conventional CABG (ONCAB) in such patients.

METHODS

Retrospective single-centre propensity-matched analysis comparing early- and long-term outcomes of OPCAB and ONCAB in patients with severe LVD. Primary outcome was long-term all-cause mortality.

RESULTS

Between 2002 and 2014, a total of 1161 consecutive patients with severe LVD underwent isolated CABG [442 patients underwent OPCAB and 719 ONCAB (430 matched pairs)]. Incomplete revascularization was observed more frequently among OPCAB than ONCAB patients (35.3% vs 21.6%; P < 0.01). The overall 30-day mortality was 5% and was comparable between the matched groups [OR 0.64 (0.34-1.22); P = 0.18]. OPCAB patients had shorter median hospital stay (11 vs 12 days; P = 0.02) and lower packed red blood cell transfusion rates [2.7 (2.21-3.19) vs 4.4 (3.56-5.24); P < 0.01]. Estimated adjusted survival was 86.0% vs 85.8%, 69.1% vs 65.5% and 59.9% vs 49.1% at 1, 5 and 10 years for OPCAB and ONCAB patients, respectively (P = 0.99). Long-term risk of mortality was similar between groups [hazard ratio (HR) 0.94 (0.66-1.32); P = 0.7]. Incomplete revascularization was weakly associated with increased risk of long-term all-cause mortality [HR 1.33 (0.99-1.77); P = 0.05].

CONCLUSIONS

OPCAB is safe and effective in patients with severe LVD. Although incomplete revascularization is more commonly observed in patients undergoing OPCAB, it is not associated with increased late mortality.

Feasibility of off-pump coronary artery grafting for patients with impaired left ventricular ejection fraction: A retrospective cohort study from a single institutional database

OBJECTIVE

Despite substantial advances in surgical practice, the management of patients with impaired left ventricular ejection fraction (LVEF) remains challenging. Furthermore, evidence on the outcomes of off-pump coronary artery bypass (OPCAB) surgery in this population is inconsistent. We conducted the present study to compare the short- and long-term outcomes of OPCAB in patients with different ejection fractions.

METHODS

This retrospective cohort study used data from the Hua-Shan Cardiac Surgery and included consecutive patients aged ≥ 18 years who underwent OPCAB procedures during 2016-2019. The patients included in the study were followed up until death or the end of data collection. Patients with different ejection fractions were matched 1:2 using propensity score matching. Factors associated with short-term outcomes were determined using logistic regression, and Kaplan-Meier survival analyses for the differences in all-cause death were generated.

RESULTS

The two propensity score matched groups consisted of 40 left ventricular dysfunction (LVD) and 80 normal left ventricular function (NLVF) patients. No significant intergroup differences were observed in the postoperative outcomes for the occurrence of left heart failure (22.5% in LVD vs. 5.0% in NLVF, p = .009). Age (odds ratio = 1.11, 95% confidence interval = 1.04-1.18) but not the preoperative LVEF was shown to be a strong predictor of short-term events in logistic regression analyses. Kaplan-Meier curves displayed similar freedom from all-cause death (p = .119) or cardio-death (p = .092) between groups.

CONCLUSION

The immediate postoperative outcomes and long-term outcomes were similar between the groups, indicating that OPCAB is a safe and effective choice for patients with LVD.

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

Objectives

Does the manipulation of the off-pump CABG (OPCAB) in patient with depressed left ventricular function is better than on-pump CABG (ONCAB) approach in in-hospital mortality and morbidities? Here we undertook a meta-analysis of the best evidence available on the comparison of primary and second clinical outcomes of the off-pump and on-pump CABG.

Design

Systematic literature reviewer and meta-analysis.

Data sources

PubMed, EMBASE, Web of science and Cochrane Center Registry of Controlled Trials were searched the studies which comparing the use of the off-pump CABG(OPCAB) and on-pump CABG (ONCAB) for patients with LVD during January 1990.1 to January 2018.

Eligibility criteria

All observation studies and randomized controlled trials comparing on-pump and off-pump as main technique for multi-vessel coronary artery disease (defined as severe stenosis (>70%) in at least 2 major diseased coronary arteries) with left ventricular dysfunction(defined as ejection fraction (EF) 40% or less) were included.

Data extraction and synthesis

Authors will screen and select the studies extract the following data, first author, year of publication, trial characters, study design, inclusion and exclusion criteria, graft type, clinical outcome, assess the risk of bias and heterogeneity. Study-specific estimates will pool through the modification of the Newcastle-Ottawa scale for the quality of study and while leave-one-out analysis will be used to detect the impact of individual studies on the robustness of outcomes.

Results

Among the 987 screened articles, a total of 16 studies (32,354 patients) were included. A significant relationship between patient risk profile and benefits from OPCAB was found in terms of the 30-day mortality (odds ratio [OR], 0.84; 95% confidence interval [CI], 0.73–0.97; P = 0.02), stroke (OR, 0.69; 95% CI, 0.55–0.86; P = 0.00), myocardial infarction (MI) (OR, 0.71; 95% CI, 0.53–0.96; P = 0.02), renal failure (OR, 0.71; 95% CI, 0.55–0.93; P = 0.01), pulmonary complication (OR, 0.68; 95% CI, 0.52–0.90; P = 0.01), infection (OR, 0.67; 95% CI, 0.49–0.91; P = 0.00),postoperative transfusion (OR, 0.25; 95% CI, 0.08–0.84; P = 0.02) and reoperation for bleeding (OR, 0.56; 95% CI, 0.41–0.75; P = 0.00). There was no significant difference in atrial fibrillation (AF) (OR, 0.96;95%; CI, 0.78–1.41; P = 0.56) and neurological dysfunction (OR, 0.88; 95% CI, 0.49–1.57; P = 0.65).

Conclusions

Compared with the on-pump CABG with LVD, using the off-pump CABG is a better choice for patients with lower mortality, stroke, MI, RF, pulmonary complication, infection, postoperative transfusion and reoperation for bleeding. Further randomized studies are warranted to corroborate these observational data.

[Results of coronary artery bypass grafting with left ventricular dysfunction (comparison of off-pump versus on-pump)]

BACKGROUND

The aim of this study was to compare the results of myocardial revascularisation with or without cardiopulmonary bypass in patients with impaired left ventricular function.

PATIENTS AND METHODS

Five hundred and sixteen consecutive patients who underwent coronary artery bypass grafting from January 2000 through December 2007 were analyzed retrospectively. One hundred and eight cases had a left ventricular EF (ejection fraction) of 45% or less. Of these patients, 78 underwent conventional coronary artery bypass (CCABG) and 30 underwent off-pump procedure (OCABG). The CCABG group received 300IU/kg of heparin while the OCABG received 100IU/kg. The off-pump coronary surgery was carried out using a tissue stabilizer Octopus II. Different pre-, per- and postoperative variables were evaluated among both groups. Statistical analysis was performed by SPSS 11.5. The variables were compared between these two groups using univariate analysis (Chi(2) test, Fisher's test exact) for qualitative variable and (Student's t test, Mann-Whitney's test) for quantitative variable.

RESULTS

Patients profiles and risk factors were similar among both groups except for age (CCABG: 57.8±9.2 year vs OCABG: 52±9.9 year; P=0.004) and left ventricular EF (CCABG: 37.4±6.3% vs OCABG: 34±7.8%; P=0.02). The number of grafts performed per patient was significantly more among patients who underwent extracorporeal circulation (CCABG: 2.53±0.7 graft/patient vs OCABG: 1.77±0.8 graft/patient; P<0.0001). The hospital mortality was more among CCABG group 9% vs 3.3% in OCABG but the difference was not significant (P=0.3). However, the operative time and the operative room stay were long in CCABG (252±61min vs 175±38min; P<0.0001 - 389±70min vs 298±54min; P<0.0001). The ventilation time was also long in CCABG (32.3±67hour vs 10.4±5.9hour; P=0.15). There was more postoperative myocardial infarction in CCABG (P=0.008), but the EF increased and was better in CCABG.

CONCLUSION

Off-pump coronary artery bypass surgery provides satisfactory operative results for most patients with reduced left ventricular function. Prospective and randomly study will be necessary before concluding.

Off-pump coronary artery bypass grafting--the current state

The optimal strategy for coronary revascularization remains controversial. Currently, most surgical revascularizations are performed with the use of cardiopulmonary bypass (ONCAB), yet over the past 20 years off-pump coronary artery bypass grafting (OPCAB) has been increasingly used because of the increased awareness of the deleterious effects of cardiopulmonary bypass (CPB) and aortic manipulation. Small, prospective, randomized controlled trials have lacked sufficient sample size to demonstrate differences in early and long-term outcomes. Larger observational studies that are better powered to statistically compare outcomes have shown more favorable in-hospital outcomes and equivalent long-term outcomes with OPCAB and ONCAB. The benefits of OPCAB techniques may be more apparent for patients at high risk for complications associated with CPB and aortic manipulation. Recent studies have demonstrated improved outcomes in higher-risk patients undergoing OPCAB, as well as improved neurological outcomes. The purpose of this review is to outline the recent literature comparing OPCAB with ONCAB, and to demonstrate efficacy of OPCAB as a useful technique for coronary revascularization.

Does off-pump coronary artery bypass surgery have a beneficial effect on mortality in patients with left ventricular dysfunction?

A best evidence topic was written according to a structured protocol. The question addressed was whether off-pump coronary artery bypass surgery (OPCAB) offered any beneficial effect on mortality when compared with on-pump coronary artery bypass surgery (ONCAB) in patients with left ventricular dysfunction (LVD). A total of 491 papers were found using the reported searches of which 17 represented the best evidence. The authors, date, journal, study type, outcome measures and results are tabulated. The 17 studies (only containing patients with LVD) comprised of one prospective randomized trial, one meta-analysis and 15 retrospective studies. The prospective trial associated the OPCAB technique with significantly lower in-hospital mortality. By comprising of seven studies and 1512 patients, the meta-analysis showed no significant difference in terms of operative mortality. Of the retrospective studies, all 15 compared short-term mortality (<30-day) of which four showed significantly lower mortality in the OPCAB group. Nine of the studies compared mid-term mortality (30 days to 5 years) with no significant difference detected and three of the studies compared long-term mortality (>5 years) with no significant difference detected. We conclude that there is limited evidence to associate the OPCAB technique with improved short-term mortality. The majority of the studies suffered from significant limitations such as containing data from operations carried out prior to the year 2000, a period when off-pump surgery was in its infancy. They frequently contained major differences in baseline characteristics with no specific inclusion/exclusion criteria, description of handling of patients converted from off-pump to bypass or reporting of myocardial viability and concomitant mitral regurgitation. Nine studies reported completeness of revascularization of which eight associated the OPCAB group with a poorer degree of revascularization making comparisons less valid. The lack of high-quality data indicates that prospective randomized trials are needed. The CRISP Trial ('Coronary artery grafting in high-risk patients randomized to off-pump or on-pump surgery') has recently been halted due to recruitment difficulties. The CORONARY ('Coronary artery bypass surgery off- or on-pump revascularization study') trial is a large international multicentre randomized study that is recruiting well and is likely to provide valuable information in the near future.

Relationship between N-terminal pro-B-type natriuretic peptide and renal function: the effects on predicting early outcome after off-pump coronary artery bypass surgery

Background

Plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) provide useful prognostic predictors in patients after cardiac surgery. However, predictive accuracy of NT-proBNP levels has varied significantly according to renal dysfunction. The purpose of this study was to assess whether preoperative NT-proBNP levels could be used as predictors of early postoperative outcomes on the basis of renal function in patients undergoing off-pump coronary artery bypass surgery (OPCAB).

Methods

In 219 patients undergoing elective OPCAB, NT-proBNP and an estimated glomerular filtration rate (eGFR) were assessed preoperatively. All patients were divided into 3 groups according to tertiles of eGFR: the first (eGFR ≥ 90 ml/min/1.73 m²), the second (90 ml/min/1.73 m² > eGFR ≥ 72 ml/min/1.73 m²) and the third tertile group (eGFR < 72 ml/min/1.73 m²). End point was the composite of early postoperative complications defined as myocardial infarction, new onset atrial fibrillation, ventricular dysfunction, prolonged mechanical ventilator care (> 48 hr), prolonged ICU stay (≥ 3 days), and in hospital mortality.

Results

There was no difference in early postoperative complications among groups. A preoperative NT-proBNP level of 228 pg/ml and 302 pg/ml (sensitivity 70%, specificity 67%, P < 0.001 and sensitivity 73%, specificity 63%, P = 0.001, respectively) were optimal cut-off values predicting complicated early postoperative course in second and third tertile group, respectively.

Conclusions

Preoperative NT-proBNP levels seem to be predictive of early postoperative complications in patients with eGFR < 90 ml/min/1.73 m² undergoing OPCAB.

Revascularization among patients with severe left ventricular dysfunction: a meta-analysis of observational studies

AIMS

Coronary artery bypass graft (CABG) surgery is the standard of care for the management of patients with severe three-vessel and left main coronary artery disease (CAD). However, the optimal strategy for management of patients with CAD and severe left ventricular (LV) dysfunction [ejection fraction (EF) ≤35%] is not clear. A meta-analysis of observational studies was performed to determine the operative mortality and long-term (5-year actuarial survival) outcomes among patients with severe LV dysfunction undergoing CABG.

METHODS AND RESULTS

A systematic computerized literature search was performed and observational studies consisting of patients undergoing isolated CABG for CAD and severe LV dysfunction were included. Studies that did not report operative mortality, long-term (≥1 year) survival data, or pre-operative EF and multiple studies from the same group were excluded. In total, 4119 patients from 26 observational clinical studies were included. The estimated mean age was 63.9 years and 82.4% of patients were men. The mean (estimate) pre-operative EF was 24.7% (95% CI 22.5-27.0%). The operative mortality among patients (26 studies, n= 3621) who underwent on-pump CABG was 5.4%, n= 189 (95% CI 4.5-6.4%). The 5-year actuarial survival among patients (13 studies, n= 1980) who underwent on-pump CABG was 73.4%, n= 1483 (95% CI 68.7-77.7%). Patients who underwent off-pump CABG (7 studies, n= 498) tended to have reduced operative mortality of 4.4%, n= 20 (95% CI 2.8-6.4%). The mean (estimate) post-operative EF was 35.19% (95% CI 31.95-38.43%).

CONCLUSION

The present meta-analysis demonstrates that based on data from available observational clinical studies, CABG can be performed with acceptable operative mortality and 5-year actuarial survival in patients with severe LV dysfunction.

The influence of a low ejection fraction on long-term survival in systematic off-pump coronary artery bypass surgery

OBJECTIVE

Poor left-ventricular ejection fraction (EF) is a recognized operative and long-term risk factor in coronary artery bypass surgery. Over the past decade, off-pump coronary artery bypass surgery has emerged as a new strategy to address myocardial revascularization in poor left-ventricular EF patients, but few reports have documented long-term results. The aim of this study was to investigate long-term clinical results in off-pump coronary artery bypass patients with ≤ 35% left-ventricular EF.

METHODS

From September 1996 to May 2006, 1250 patients underwent off-pump coronary artery bypass revascularization, and were prospectively followed-up at the Montreal Heart Institute. Among them, 137 patients (pts) had a preoperative left-ventricular EF ≤ 35%. Follow-up was completed in 97% of patients.

RESULTS

Mean follow-up was 66 ± 34 months. Rate of grafts per pts was comparable in both groups. Overall 30-day mortality was 1.7% (1.5% EF >35% pts vs 2.9% in EF ≤ 35% pts; p = 0.19). Ten-year survival was lower in poor EF patients (44 ± 7% vs 76 ± 2%), and remained significant even after adjusting for risk factors (p = 0.04). Freedom from cardiac death for both groups was also significantly reduced in poor EF patients (p = 0.008). After adjustment, freedom from the combined end point of cardiac or sudden death, myocardial infarction, repeat coronary revascularization, unstable angina, and cardiac failure was comparable in both groups (p = 0.5).

CONCLUSIONS

Off-pump coronary artery bypass surgery can be performed adequately and safely in poor EF patients. However, overall and cardiac survival was decreased in this subset of patients with a comparable freedom from major cardiac adverse related events.

Off-pump coronary artery bypass surgery in selected patients is superior to the conventional approach for patients with severely depressed left ventricular function

OBJECTIVES

Patients with coronary artery disease and left ventricular dysfunction have high mortality when kept in clinical treatment. Coronary artery bypass grafting can improve survival and the quality of life. Recently, revascularization without cardiopulmonary bypass has been presented as a viable alternative. The aim of this study is to compare patients with left ventricular ejection fractions of less than 20% who underwent coronary artery bypass graft with or without cardiopulmonary bypass.

METHODS

From January 2001 to December 2005, 217 nonrandomized, consecutive, and nonselected patients with an ejection fraction less than or equal to 20% underwent coronary artery bypass graft surgery with (112) or without (off-pump) (105) the use of cardiopulmonary bypass. We studied demographic, operative, and postoperative data.

RESULTS

There were no demographic differences between groups. The outcome variables showed similar graft numbers in both groups. Mortality was 12.5% in the cardiopulmonary bypass group and 3.8% in the off-pump group. Postoperative complications were statistically different (cardiopulmonary bypass versus off-pump): total length of hospital stay (days)-11.3 vs. 7.2, length of ICU stay (days)-3.7 vs. 2.1, pulmonary complications-10.7% vs. 2.8%, intubation time (hours)-22 vs. 10, postoperative bleeding (mL)-654 vs. 440, acute renal failure-8.9% vs. 1.9% and left-ventricle ejection fraction before discharge-22% vs. 29%.

CONCLUSION

Coronary artery bypass grafting without cardiopulmonary bypass in selected patients with severe left ventricular dysfunction is valid and safe and promotes less mortality and morbidity compared with conventional operations.

Management of patients with a calcified aorta or low ejection fraction undergoing multivessel coronary revascularization

Off-pump coronary artery bypass surgery (OPCAB) provides an alternative method of surgical revascularization by allowing coronary anastomoses to be constructed without the use of cardiopulmonary bypass and without manipulation of the aorta. The presence of a calcified aorta is one of the strongest indications for OPCAB because both distal and proximal anastomoses can be performed without cannulation or clamping of the aorta. In patients with left ventricular dysfunction, OPCAB techniques allow for revascularization without the need for global myocardial ischemia associated with cardioplegic arrest.

Myocardial revascularization using on-pump beating heart among patients with left ventricular dysfunction

Objectives

On-pump beating heart technique for myocardial revascularization has been used successfully among both low and high risk patients. Its application among low ejection fraction patients is limited. The aim of our study is to evaluate this technique among patients with low ejection fraction and to compare results with off-pump bypass technique.

Methods

This retrospective study includes 137 patients with ejection fraction below 0.35 who underwent isolated coronary artery bypass surgery. 39 patients underwent myocardial revascularization using on-pump beating heart (ONCAB/BH), while 98 patients had off-pump beating heart (OPCAB). Different preoperative, operative and postoperative variables were evaluated among both groups.

Results

Patients profiles and risk factors were similar among both groups, except for the number of patients undergoing redo CABG which was significantly higher among ONCAB/BH (13% vs 3%; p = 0.025). Ejection fraction (EF) varied from 10-34%. The mean EF for patients who underwent ONCAB/BH was 28 ± 6 in comparison to 26 ± 5 for OPCAB patients (P = 0.093). Predicted risk for surgery according to EuroSCORE was similar among both groups (P = 0.443). The number of grafts performed per patient was significantly more among patients who underwent ONCAB/BH (2.2 ± 0.7 Vs 1.7 ± 0.7; P = 0.002). Completeness of revascularization was significantly greater in the ONCAB/BH patients (72% Vs 46%, P = 0.015). The incidence of hospital mortality and combined major morbidity was more among ONCAB/BH in comparison to OPCAB, but the difference was not significant. However, the incidence of blood loss, ventricular arrythmias, inotropic support, ICU, hospital stay and blood transfusion were significantly greater among patients who underwent ONCAB/BH.

Conclusions

On-pump beating heart technique can be used in myocardial revascularization among patients with left ventricular dysfunction. The technique was found to be associated with better myocardial revascularization when compared with OPCAB technique. However, the incidence of morbidity and mortality was more than OPCAB.

Current state of surgical myocardial revascularization

Despite increasing competition from percutaneous interventions and other novel methods of non-surgical coronary revascularization, coronary artery bypass grafting (CABG) remains one of the most definitive and durable treatments for coronary artery disease, especially for those patients with extensive and diffuse disease. In recent years the CABG procedure itself has undergone innovation and evolution. This review article provides a brief historical perspective on the procedure, and examines the current state of modern variations including off-pump, limited-access, and robotic-assisted CABG.

Novel surgical method of proximal anastomosis in off-pump coronary artery bypass grafting

BACKGROUND

Cerebral embolization as a result of aortic manipulation has emerged as an important risk factor for the incidence of stroke after off-pump coronary artery bypass grafting (OPACB).

METHODS AND RESULTS

A new surgical technique for proximal anastomosis without using a side-biting clamp or any proximal anastomotic device in OPACB has been developed and successfully used for proximal anastomosis between a great saphenous vein or radial artery graft and the aorta in OPCAB of 138 patients, with good short-term results.

CONCLUSIONS

This novel technique proximal anastomosis in OPACB can be completed in a safe, easy and economical fashion.

Off-pump coronary bypass surgery for high-risk patients: only in expert centers?

PURPOSE OF REVIEW

Off-pump coronary artery bypass (OPCAB) grafting has been increasingly adopted in an effort to prevent deleterious effects of cardiopulmonary bypass, including the associated inflammatory response, global myocardial ischemia and the risks of aortic manipulation. In many studies, the greatest benefit of OPCAB has been in high-risk patients. This review will summarize the recent literature examining outcomes of OPCAB versus on-pump coronary artery bypass in high-risk subgroups, and will examine the safety of routine application of OPCAB in these patients.

RECENT FINDINGS

Prospective randomized trials have shown that in comparison to on-pump coronary artery bypass, OPCAB reduces perioperative morbidity, but have failed to show a mortality benefit, owing to small sample sizes. However, numerous large retrospective series and meta-analyses have demonstrated a reduction in risk-adjusted mortality and morbidity with respect to the following outcomes: stroke, pulmonary function, renal function, atrial fibrillation, need for early reoperation, blood transfusion requirements, length of ICU and hospital stay, and hospital costs. An even greater benefit has been seen in the following high-risk patients: those with acute myocardial infarction, left ventricular dysfunction, previous history of stroke, renal insufficiency, women, elderly patients, and those undergoing reoperations.

SUMMARY

Risk-adjusted outcomes are superior after OPCAB versus on-pump coronary artery bypass for mortality and numerous morbidity endpoints. This benefit is most easily demonstrated in high-risk patient populations.