Preoperative intra-aortic balloon pump to reduce mortality in coronary artery bypass graft: a meta-analysis of randomized controlled trials

Preoperative intra-aortic balloon pump in patients with ST-elevation myocardial infarction undergoing urgent cardiac bypass surgery

BACKGROUND

In patients with ST-elevation myocardial infarction (STEMI), either with or without cardiogenic shock, mechanical circulatory support with an intra-aortic balloon pump (IABP) is not associated with lower mortality. However, in STEMI patients undergoing urgent coronary artery bypass grafting (CABG), preoperative insertion of an IABP has been suggested to reduce mortality. In this study, the effect of preoperative IABP use on mortality in STEMI patients undergoing urgent CABG was investigated.

METHODS

All consecutive STEMI patients undergoing urgent CABG in a single centre between 2000 and 2018 were studied. The primary outcome, 30-day mortality, was compared between patients with and without a preoperative IABP. Subgroup analysis and multivariable analysis using a propensity score and inverse probability treatment weighting were performed to adjust for potential confounders.

RESULTS

A total of 246 patients were included, of whom 171 (69.5%) received a preoperative IABP (pIABP group) and 75 (30.5%) did not (non-pIABP group). In the pIABP group, more patients suffered from cardiogenic shock, persistent ischaemia and reduced left ventricular function. Unadjusted 30-day mortality was comparable between the pIABP and the non-pIABP group (13.3% vs 12.3%, p = 0.82). However, after correction for confounders and inverse probability treatment weighting preoperative IABP was associated with reduced 30-day mortality (relative risk 0.52, 95% confidence interval 0.30-0.88).

CONCLUSION

In patients with STEMI undergoing urgent CABG, preoperative insertion of an IABP is associated with reduced mortality.

Impact of preoperative intra-aortic balloon pump on outcomes in coronary artery bypass grafting for unprotected left-main coronary artery disease

Background

Preoperative intra-aortic balloon pump (IABP) before coronary artery bypass grafting (CABG) could improve operative outcomes by augmenting the diastolic coronary blood flow. Data on preoperative IABP use in patients with left-main coronary artery (LMCA) disease are limited. This study aimed to characterize patients who received preoperative IABP before CABG for LMCA and evaluate its effect on postoperative outcomes.

Methods

This multicenter retrospective cohort study that included consecutive 914 patients who underwent CABG for unprotected LMCA disease from January 2015 to December 2019 in 14 tertiary referral centers. Patients were grouped according to the preoperative IABP insertion into patients with IABP (n=101) and without IABP (n=813). Propensity score matching adjusting for preoperative variables, with 1:1 match and a caliber of 0.03 identified 80 matched pairs. The primary outcomes used in propensity score matching were cardiac mortality and major adverse cardiac and cerebrovascular events (MACCE).

Results

IABP was commonly inserted in patients with previous myocardial infarction (MI), chronic kidney disease, peripheral arterial disease, and congestive heart failure. IABP patients had higher EuroSCORE [ES >8%: 95 (11.86%) vs. 40 (39.60%), P<0.001] and SYNTAX {29 [interquartile range (IQR) 25-35] vs. 33 (IQR 26-36); P=0.02} scores. Preoperative cardiogenic shock and arrhythmia were more prevalent in patients with IABP, while acute coronary syndrome was more prevalent in patients without IABP. After matching, there was no difference in vasoactive inotropic score between groups [3.5 (IQR 1-7.5) vs. 6 (IQR 1-13.5), P=0.06], and lactate levels were nonsignificantly higher in patients with IABP [2.4 (IQR 1.4-4.5) vs. 3.1 (IQR 1.05-7.75), P=0.05]. There were no differences between groups in acute kidney injury [20 (25%) vs. 26 (32.5%), P=0.34], cerebrovascular accidents [3 (3.75%) vs. 4 (5%), P>0.99], heart failure [5 (6.25%) vs. 7 (8.75%), P=0.75], MI [7 (8.75%) vs. 8 (10%), P>0.99], major adverse cardiac and cerebrovascular events [10 (12.5%) vs. 17 (21.25%), P=0.21], and cardiac mortality [6 (7.50%) vs. 14 (17.50%), P=0.09]. Patients who received IABP had longer ventilation times [8.5 (IQR 6-23) vs. 15.5 (IQR 5-50.5) h, P=0.03] and intensive care unit (ICU) stays [3 (IQR 2-5) vs. 4 (IQR 2-7.5) days, P=0.01].

Conclusions

Preoperative IABP in patients with LMCA might not be associated with reduced cardiac mortality or hospital complications. IABP could increase the duration of mechanical ventilation and ICU stay, and its use should be individualized for each patient.

Risk Factors and Short-Term Outcomes of Postoperative Pulmonary Complications in Elderly Patients After Cardiopulmonary Bypass

Objective

The risk factors of postoperative pulmonary complications (PPCs) have been extensively investigated in non-cardiac surgery and non-elderly adult patients undergoing cardiac surgery. However, data on elderly patients after cardiopulmonary bypass (CPB) is limited. This study aimed to evaluate the risk factors and short-term outcomes for PPCs in elderly patients undergoing CPB procedures.

Patients and Methods

Data from 660 patients who underwent CPB over a six-year period at a tertiary care hospital were collected. The primary outcome encompassed the incidence of PPCs, including re-intubation, postoperative mechanical ventilation exceeding 48 hours, pulmonary infection, pleural effusion requiring thoracic drainage, and acute respiratory distress syndrome. Missing data were managed using multiple imputation. Univariate analysis and the multiple logistic regression method were utilized to ascertain independent risk factors for PPCs.

Results

Among the 660 patients, PPCs were observed in 375 individuals (56.82%). Multiple logistic regression identified serum albumin levels <40 g/L, type of surgery, CPB duration >150 minutes, blood transfusion, and intra-aortic balloon pump use before extubation as independent risk factors for PPCs. Patients experiencing PPCs had prolonged mechanical ventilation, extended hospitalization and ICU stays, elevated postoperative mortality, and higher tracheotomy rates compared to those without PPCs.

Conclusion

Elderly patients following CPB displayed a substantially high incidence of PPCs, significantly impacting their prognosis. Additionally, this study identified five prominent risk factors associated with PPCs in this population. These findings enable clinicians to better recognize patients who may benefit from perioperative prevention strategies based on these risk factors.

Skeletonized versus Pedicled harvesting of internal mammary artery: A systematic review and Meta-analysis

There are two recognized internal mammary artery (IMA) harvesting techniques during coronary artery bypass grafting (CABG): pedicled and skeletonized. This systematic review and meta-analysis sought to compare the clinical outcomes of the two harvesting techniques. A comprehensive electronic literature search of PubMed, Scopus, and Embase was conducted from inception till June 2023. Thirty-one studies with a total of 13005 patients met our inclusion criteria. The results from the included studies were presented as weighted mean difference (WMD) with its relevant standard deviation (SD) for continuous variables, while Odds Ratio (OR) was used for dichotomous variables. A 95% confidence interval (CI) was used, and the results were pooled using a random effects model. The skeletonized IMA demonstrated a significantly reduced risk of sternal wound infection (SWI) compared to the pedicled IMA (OR = 0.45 [95% CI, 0.32-0.66]; p = 0.0001). The conduit length used was significantly longer in the skeletonized IMA (WMD -2.48, 95% CI, [-3.75, -1.20], P = 0.0001) and a significantly higher postoperative flow rate was observed while using skeletonization compared to the pedicled harvesting (WMD -13.11, 95% CI, [-22.52, -3.70], P = 0.006). However, no significant difference was seen in mortality between the two techniques (OR = 1.19 [95% CI, 1.00-1.41]; p = 0.05). Pedicled harvesting demonstrated significantly reduced incidents of MI (OR = 1.38 [95% CI, 1.13-1.69]; p = 0.002), while significant results in graft patency were observed favoring pedicled harvesting over skeletonization (OR = 0.63 [95% CI, 0.40-0.98]; p = 0.04).

Prediction of low cardiac output syndrome in patients following cardiac surgery using machine learning

Background

This study aimed to develop machine learning models to predict Low Cardiac Output Syndrome (LCOS) in patients following cardiac surgery using machine learning algorithms.

Methods

The clinical data of cardiac surgery patients in Nanjing First Hospital between June 2019 and November 2020 were retrospectively extracted from the electronic medical records. Six conventional machine learning algorithms, including logistic regression, support vector machine, decision tree, random forest, extreme gradient boosting and light gradient boosting machine, were employed to construct the LCOS predictive models with all predictive features (full models) and selected predictive features (reduced models). The discrimination of these models was evaluated by the area under the receiver operating characteristic curve (AUC) and the calibration of the models was assessed by the calibration curve. Shapley Additive explanation (SHAP) and Local Interpretable Model-Agnostic Explanations (LIME) were used to interpret the predictive models.

Results

Data from 1,585 patients [982 (62.0%) were male, aged 18 to 88, 212 (13.4%) with LCOS] were employed to train and validate the LCOS models. Among the full models, the RF model (AUC: 0.909, 95% CI: 0.875–0.943; Sensitivity: 0.849, 95% CI: 0.724–0.933; Specificity: 0.835, 95% CI: 0.796–0.869) and the XGB model (AUC: 0.897, 95% CI: 0.859–0.935; Sensitivity: 0.830, 95% CI: 0.702–0.919; Specificity: 0.809, 95% CI: 0.768–0.845) exhibited well predictive power for LCOS. Eleven predictive features including left ventricular ejection fraction (LVEF), first post-operative blood lactate (Lac), left ventricular diastolic diameter (LVDd), cumulative time of mean artery blood pressure (MABP) lower than 65 mmHg (MABP &lt; 65 time), hypertension history, platelets level (PLT), age, blood creatinine (Cr), total area under curve above threshold central venous pressure (CVP) 12 mmHg and 16 mmHg, and blood loss during operation were used to build the reduced models. Among the reduced models, RF model (AUC: 0.895, 95% CI: 0.857–0.933; Sensitivity: 0.830, 95% CI: 0.702–0.919; Specificity: 0.806, 95% CI: 0.765–0.843) revealed the best performance. SHAP and LIME plot showed that LVEF, Lac, LVDd and MABP &lt; 65 time significantly contributed to the prediction model.

Conclusion

In this study, we successfully developed several machine learning models to predict LCOS after surgery, which may avail to risk stratification, early detection and management of LCOS after cardiac surgery.

Predictors of unplanned 30-day readmissions after coronary artery bypass graft: a systematic review and meta-analysis of cohort studies

AIMS

Coronary artery bypass graft (CABG) is one of the most performed cardiac surgery globally. CABG is known to have a high rate of short-term readmissions. The 30-day unplanned readmission rate as a quality measure is associated with adverse health outcomes. This study aimed to identify and synthesize the perioperative risk factors for 30-day unplanned readmission after CABG.

METHODS AND RESULTS

We systematically searched seven databases and reviewed studies to identify all eligible English articles published from 1 October 1999 to 30 September 2019. Random-effect models were employed to perform pooled analyses. Odds ratio and 95% confidence interval were used to estimate the risk factors for 30-day unplanned readmission. The 30-day hospital readmission rates after CABG ranged from 9.2% to 18.9% in 14 cohort studies. Among preoperative characteristics, older adults, female, weight loss, high serum creatinine, anticoagulant use or dialysis, and comorbidities were found to be statistically significant. Postoperative complications, prolonged length of hospital stay, and mechanical ventilation were revealed as the postoperative risk factors for 30-day unplanned readmission. However, intraoperative risk factors were not found to be significant in this review.

CONCLUSION

Our findings emphasize the importance of a comprehensive assessment during the perioperative period of CABG. Healthcare professionals can perform a readmission risk stratification and develop strategies to reduce readmission rates after CABG using the risk factors identified in this review. Future studies with prospective cohort samples are needed to identify the personal or psychosocial factors influencing readmission after CABG, including perioperative risk factors.

Temporary mechanical circulatory support prevents the occurrence of a low-output state in high-risk coronary artery bypass grafting: A case series

BACKGROUND

Coronary artery bypass grafting (CABG) is a durable treatment for coronary artery disease. Left ventricular dysfunction (LVD) (a division of cardiothoracic surgery) (ejection fraction < 35%) significantly elevates perioperative risk for patients pursuing surgical revascularization. Periprocedural support with temporary mechanical circulatory support (tMCS) has shown benefit in this patient population.

METHODS

Four patients with ischemic cardiomyopathy and LVD underwent CABG at our institution between 2017 and 2018. Each patient received perioperative ventricular support using a microaxial tMCS device (Impella 5.0®). The occurrence of a postoperative low-output state (LOS) was assessed for as well as postoperative morbidity and mortality, device-specific complications, and tMCS support duration.

RESULTS

All patients survived to device explant without device-related complications. Two patients required reoperation for nondevice-related bleeding. All patients were without an LOS at 24 h postoperatively with cardiac indices of 2.9-3.6 L/min/m² , normalized serum lactate, and vasoactive-inotrope scores of 0-12.0. There was a notably high incidence of acute renal failure (50%), which was observed in patients with preoperative cardiogenic shock. One patient died 10 days after the device explant. Of the three patients that survived to discharge, two were alive at the most recent follow-up. Postoperative device support varied widely (0-500 h).

CONCLUSION

Perioperative tMCS may be a viable strategy for preventing postoperative LOS in high-risk CABG patients with a low complication rate and acceptable morbidity. The application of microaxial tMCS devices in CABG is an area that warrants further investigation to delineate its impact on perioperative outcomes and potentially expand the indications for such devices.

Preoperative Intra-Aortic Balloon Pumps in Cardiac Surgery: A Propensity Score Analysis

INTRODUCTION

The role of intra-aortic balloon pumps (IABP) in high-risk patients undergoing coronary artery bypass graft (CABG) surgery remains controversial. We report the 5-year experience from a new Australian centre.

METHODS

We retrospectively analysed 690 patients undergoing urgent isolated CABG surgery at a Western Australian tertiary centre from February 2015 to May 2020. De-identified data was obtained from the Australia & New Zealand Society of Cardiothoracic Surgeons database. Patients were stratified according to preoperative IABP use. A propensity score was created for the probability of IABP use and a propensity adjusted analysis was performed using logistic regression. The primary outcome was 30-day mortality. Secondary outcomes were postoperative inhospital outcomes.

RESULTS

Preoperative IABP was used in 78 patients (11.3%). After propensity score adjustment, in a subgroup of patients with reduced ejection fraction or left main disease, 30-day mortality (7.0% vs 2.0%, OR 6.03, 95% CI 1.89-19.28, p=0.002) was significantly higher in the IABP group. Red blood cell transfusions (19.7% vs 12.6%, OR 1.86, 95% CI 1.02-3.35, p=0.039), prolonged inotrope use (78.9% vs 50.9%, OR 6.11, 95% CI 2.77-13.48, p<0.001), prolonged invasive ventilation (28.2% vs 3.4%, OR 20.2, 95% CI 8.24-49.74, p<0.001), mesenteric ischaemia (2.8% vs 0%, OR 4.52, 95% CI 1.15-17.77, p=0.031) and multisystem organ failure (1.3% vs 0.7%, OR 25.68, 95% CI 2.55-258.34, p=0.006) were significantly higher in the IABP group.

CONCLUSION

In patients undergoing isolated CABG surgery, preoperative IABP use was associated with increased 30-day mortality and adverse outcomes. Large randomised controlled trials are required to confirm our findings.

Evaluation of β-blocker therapy for long-term outcomes in patients with low ejection fraction after cardiac surgery

Background

Preoperative low left ventricular ejection fraction (LVEF) has been reported as an independent risk factor for in-hospital mortality. However, there were few studies evaluating the long-term mortality in these patients. We, therefore, conducted this study to investigate long-term outcomes of surgery on patients with LVEF≤35% undergoing a broad range of cardiac procedures.

Methods

We performed a retrospective cohort study in 510 patients from January 1, 2007 to September 1, 2019. These patients were divided into survival group (n = 386) and non-survival group (n = 124). The multivariate Cox analysis was used to estimate the risk factors for survival. In Cox analysis, β-blockers were indicated to be associated with long-term mortality. To further address bias, we derived a propensity score predicting the function of β-blockers on survival, and matched 52 cases to 52 controls with similar risk profiles.

Results

Patients were followed for a median period of 24 months (interquartile range: 11–44 months). Multivariate Cox regression analysis indicated that the non-survival group had higher weight, higher EuroSCORE, more smoking patients, longer time of cardiopulmonary bypass (CPB), more intra-aortic balloon pump (IABP) use, and more patients who always used β-blocker (HR: 2.056, 95%CI:1.236–3.420, P = 0.005) compared with survival group. After propensity matching, the group which always used β-blocker showed higher rate of all-cause death compare with the control group (61.54% vs 80.77%, P = 0.030).

Conclusions

The risk factors for long-term survival were weight, EuroSCORE, smoking, CPB, IABP, always used β-blockers in patients with LVEF≤35%. The discharge prescription of β-blocker should be cautiously administrated in those patients.

Preoperative Use of Intra-Aortic Balloon Pump Support Reduced 30-Day Mortality in a Population with LVEF >35% and High Surgical Risk after Coronary Artery Bypass Graft Surgery

Introduction: The intra-aortic balloon pump (IABP) is used to prevent complications after coronary artery bypass grafting (CABG) surgery, although some results are controversial and basal ventricular function may play a role. This study assessed the benefit of preoperative use of IABP, as stratified by the ventricular function, in a population submitted to high-surgical-risk CABG. Methods: Patients >18 years old, with multiple coronary artery disease and thus candidates for CABG, were included. Cardiogenic shock, acute myocardial infarction (AMI), acute ventricle mechanical dysfunction, severe aortic regurgitation, tachyarrhythmia, massive pulmonary embolism, coagulopathy, or low life expectancy were exclusion criteria. Results: One hundred and twenty-nine patients aged 65 years old with hypertension, dyslipidemia, type 2 diabetes mellitus, and mean left ventricular ejection fraction (LVEF) 46% constituted the study population. No difference was observed at 30-day mortality endpoint (IABP vs. no IABP, 17 vs. 24%, OR 0.63, p = 0.20; AMI 25 vs. 31%, OR 0.75, p = 0.29). After LVEF stratification, the subgroup of 48 (75%) patients under IABP support and LVEF >35% had a reduced 30-day mortality risk (LVEF ≤35% vs. LVEF >35%, 37.5 vs. 10.4%, OR 0.3, p = 0.03), independently from potential confounders and showing an interaction with European System for Cardiac Operative Risk Evaluation-II (EuroSCORE-II). At secondary endpoints, IABP use was associated with a lower prevalence of acute renal failure and renal replacement therapy, but with a longer stay in the intensive care unit and longer hospitalization time. Conclusion: The preoperative use of IABP was associated with an independent reduction of 30-day mortality risk in cases with LVEF >35% in a population submitted to high-surgical-risk CABG. Likewise, the use of IABP was associated with a lower risk of postoperative renal complications.

Traumatic blunt cardiac injuries: An updated narrative review

Blunt cardiac injury (BCI) is defined as injuries sustained due to blunt trauma to the heart, and it remains unchanged for long time. The spectrum of BCI ranges from a minor "bruise" to specific postcontusion cardiac conditions such as free-wall rupture. This is a narrative review provides a continued and updates details regarding BCIs from 2008 to 2017. For this purpose, a narrative review of literature was conducted using appropriate database for retrieval of articles through systematic search methodology. Autopsy-based studies are very limited. It can be concluded that regardless of the variability in the spectrum of modalities and medical/surgical resources, BCIs diagnosis and management remain a puzzle and needs further prospective studies.

Effect of a Perioperative Intra-Aortic Balloon Pump in High-Risk Cardiac Surgery Patients: A Randomized Clinical Trial

OBJECTIVES

The aim of this study was to evaluate the efficacy of perioperative intra-aortic balloon pump use in high-risk cardiac surgery patients.

DESIGN

A single-center randomized controlled trial and a meta-analysis of randomized controlled trials.

SETTING

Heart Institute of São Paulo University.

PATIENTS

High-risk patients undergoing elective coronary artery bypass surgery.

INTERVENTION

Patients were randomized to receive preskin incision intra-aortic balloon pump insertion after anesthesia induction versus no intra-aortic balloon pump use.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was a composite endpoint of 30-day mortality and major morbidity (cardiogenic shock, stroke, acute renal failure, mediastinitis, prolonged mechanical ventilation, and a need for reoperation). A total of 181 patients (mean [SD] age 65.4 [9.4] yr; 32% female) were randomized. The primary outcome was observed in 43 patients (47.8%) in the intra-aortic balloon pump group and 42 patients (46.2%) in the control group (p = 0.46). The median duration of inotrope use (51 hr [interquartile range, 32-94 hr] vs 39 hr [interquartile range, 25-66 hr]; p = 0.007) and the ICU length of stay (5 d [interquartile range, 3-8 d] vs 4 d [interquartile range, 3-6 d]; p = 0.035) were longer in the intra-aortic balloon pump group than in the control group. A meta-analysis of 11 randomized controlled trials confirmed a lack of survival improvement in high-risk cardiac surgery patients with perioperative intra-aortic balloon pump use.

CONCLUSIONS

In high-risk patients undergoing cardiac surgery, the perioperative use of an intra-aortic balloon pump did not reduce the occurrence of a composite outcome of 30-day mortality and major complications compared with usual care alone.

Preoperative intra-aortic balloon pump inserted in acute myocardial infarction patients without cardiogenic shock undergoing surgical coronary revascularization

OBJECTIVES

The benefit of preoperative intra-aortic balloon pump implantation in high-risk cardiac surgery patients is still debated. The role of preoperative intra-aortic balloon pump insertion in acute myocardial infarction patients without cardiogenic shock undergoing off-pump coronary artery bypass grafting remains unknown. This study aimed to determine the efficacy and safety of the preoperative intra-aortic balloon pump insertion in those patients undergoing off-pump coronary artery bypass grafting.

METHODS

A total of 421 consecutive acute myocardial infarction patients without cardiogenic shock who underwent isolated off-pump coronary artery bypass grafting were enrolled in this retrospective observational propensity score-matched analysis study. Patients who received intra-aortic balloon pump before off-pump coronary artery bypass grafting (the intra-aortic balloon pump group, n = 157) were compared with those who had not (control group, n = 264). The 30-day postoperative survival, postoperative complications, and postoperative hospital length of stay were compared between the two groups.

RESULTS

A total of 99 pairs of patients were matched. The preoperative intra-aortic balloon pump did not show a 30-day postoperative survival benefit compared with the control group (hazard ratio, 0.9; 95% confidence interval, 0.2-4.2; p = 0.92). Patients with preoperative intra-aortic balloon pump were more likely to have shorter postoperative lengths of stay (8 (6-11) days vs. 10 (6-15) days, p = 0.02) and decreased total days in the hospital (median days: 18.2 vs. 21.8, p = 0.02) compared to patients without balloon pumps.

CONCLUSION

Preoperative intra-aortic balloon pump insertion in acute myocardial infarction patients without cardiogenic shock undergoing off-pump coronary artery bypass grafting improved convalescence as shown by significantly shorter postoperative lengths of hospital stay.

Factors causing prolonged mechanical ventilation and peri-operative morbidity after robot-assisted coronary artery bypass graft surgery

Robot-assisted coronary artery bypass graft [robot-assisted (coronary artery bypass grafting (CABG)] surgery is the latest treatment for coronary artery disease. However, the surgery extensively affects cardiac and pulmonary function, and the risk factors associated with peri-operative morbidity, including prolong mechanical ventilation (PMV), have not been fully examined. In this retrospective cohort study, a total of 382 patients who underwent robot-assisted internal mammary artery harvesting with mini-thoracotomy direct-vision bypass grafting surgery (MIDCABG) from 2005 to 2012 at our tertiary care hospital were included. The definition of PMV was failure to wean from mechanical ventilation more than 48 h after the surgery. Risk factors for PMV, and peri-operative morbidity and mortality were analyzed with a multivariate logistic regression model. Forty-three patients (11.3%) developed PMV after the surgery, and the peri-operative morbidity and mortality rates were 38 and 2.6%, respectively. The risk factors for PMV were age, left ventricular ejection fraction (LVEF), the duration of one-lung ventilation for MIDCABG (beating time), and peak airway pressure at the end of the surgery. Furthermore, age and anesthesia time were found to be independent risk factors for peri-operative morbidity, whereas age, LVEF, and anesthesia time were the risk factors for peri-operative mortality. These findings may help physicians to properly choose patients for this procedure, and provide more attention to patients with higher risk after surgery to achieve better clinical outcomes.

CABG in patients with left ventricular dysfunction: indications, techniques and outcomes

Ischemic chronic heart failure (CHF) represents one of the cardiovascular diseases with the worst degree of morbidity and mortality in the western world, and with the highest health care costs. Despite several studies demonstrated that surgical revascularization (CABG), especially in the presence of viable myocardium, improve heart function, and therefore, survival, the matter remains unclear and controversial. In the late 1970s, the Coronary Artery Surgery Study showed that a subgroup of patients with coronary artery disease, angina, and reduce LV function had a significant survival benefit after CABG compared to those treated medically. The key concept behind this observation was the presence of viable myocardium, which can resume function following revascularization. In contrary, the surgical treatment for ischemic heart failure (STICH) trial, which randomized patients with CAD and LV dysfunction to evidence-based medical therapy or CABG plus medical therapy, failed to demonstrate at a median follow-up of 56 months a significant difference between the CABG group and the medical therapy group in the rate of death from any cause. However, the results of the STICH extension study (STICHES) at 10 years follow-up demonstrated that CABG is associated with a significant reduction in all-cause mortality, cardiovascular mortality, and readmission for heart compared to optimal medical therapy (OMT) in patients with severe ischemic LV dysfunction. Therefore, this review discusses the available evidences in literature, from observational studies to randomized trials, including operative techniques and controversial issues, in order to better clarify the role of CABG in the current management of ischemic patients with LVD.

Intra-aortic balloon pump: current evidence & future perspectives

The intra-aortic balloon pump (IABP) is frequently used to support severely compromised ventricles in critically ill patients. Its relatively affordability and ease of insertion has cemented its position as the first line of treatment for hemodynamic support in cardiogenic shock. Accordingly, the current ACC/AHA recommendations maintain a Class 2A for the use of IABP in shock. However, a review of the current literature suggests that the evidence supporting the American College of Cardiology and American Heart Association (ACC/AHA) guidelines are equivocal. Alternative uses for IABP such as perioperative support during high-risk cardiac surgery, treatment of left ventricular distention on extracorporeal membrane oxygenation, and as bridge to transplant have been proposed. The effectiveness of the IABP in these clinical situations remains largely unproven, due to the paucity of available data.

Outcome of cardiac surgery in patients with low preoperative ejection fraction

Background

In patients undergoing cardiac surgery, a reduced preoperative left ventricular ejection fraction (LVEF) is common and is associated with a worse outcome. Available outcome data for these patients address specific surgical procedures, mainly coronary artery bypass graft (CABG). Aim of our study was to investigate perioperative outcome of surgery on patients with low pre-operative LVEF undergoing a broad range of cardiac surgical procedures.

Methods

Data from patients with pre-operative LVEF ≤40 % undergoing cardiac surgery at a university hospital were reviewed and analyzed. A subgroup analysis on patients with pre-operative LVEF ≤30 % was also performed.

Results

A total of 7313 patients underwent cardiac surgery during the study period. Out of these, 781 patients (11 %) had a pre-operative LVEF ≤40 % and were included in the analysis. Mean pre-operative LVEF was 33.9 ± 6.1 % and in 290 patients (37 %) LVEF was ≤30 %. The most frequently performed operation was CABG (31 % of procedures), followed by mitral valve surgery (22 %) and aortic valve surgery (19 %). Overall perioperative mortality was 5.6 %. Mitral valve surgery was more frequent among patients who did not survive, while survivors underwent more frequently CABG. Post-operative myocardial infarction occurred in 19 (2.4 %) of patients, low cardiac output syndrome in 271 (35 %). Acute kidney injury occurred in 195 (25 %) of patients. Duration of mechanical ventilation was 18 (12–48) hours. Incidence of complications was higher in patients with LVEF ≤30 %. Stepwise multivariate analysis identified chronic obstructive pulmonary disease, pre-operative insertion of intra-aortic balloon pump, and pre-operative need for inotropes as independent predictors of mortality among patients with LVEF ≤40 %.

Conclusions

We confirmed that patients with low pre-operative LVEF undergoing cardiac surgery are at higher risk of post-operative complications. Cardiac surgery can be performed with acceptable mortality rates; however, mitral valve surgery, was found to be associated with higher mortality rates in this population. Accurate selection of patients, risk/benefit evaluation, and planning of surgical and anesthesiological management are mandatory to improve outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0271-5) contains supplementary material, which is available to authorized users.

Preoperative intra-aortic balloon pump improves the clinical outcomes of off-pump coronary artery bypass grafting in left ventricular dysfunction patients

Severe left ventricular (LV) dysfunction patients undergoing off-pump coronary artery bypass grafting (OPCAB) are often associated with a higher mortality. The efficacy and safety of the preoperative prophylactic intra-aortic balloon pump (IABP) insertion is not well established. 416 consecutive patients with severe LV dysfunction (ejection fraction ≤35%) undergoing isolated OPCAB were enrolled in a retrospective observational study. 191 patients was enrolled in the IABP group; the remaining 225 patients was in control group. A total of 129 pairs of patients were propensity-score matched. No significant differences in demographic and preoperative risk factors were found between the two groups. The postoperative 30-day mortality occurred more frequently in the control group compared with the IABP group (8.5% vs. 1.6%, p = 0.02). There was a significant reduction of low cardiac output syndrome in the IABP group compared with the control group (14% vs. 6.2%, p = 0.04). Prolonged mechanical ventilation (≥48 h) occurred more frequently in the control group (34.9% vs. 20.9%, p = 0.02). IABP also decreased the postoperative length of stay. Preoperative IABP was associated with a lower 30-day mortality, suggesting that it is effective in patients with severe LV dysfunction undergoing OPCAB.

Limb salvage following iatrogenic arterial injury: complications of cardiac support using intra-aortic balloon pumps

This is a unique case report describing complex limb salvage in a patient who experienced acute limb ischaemia due to a complication of intra-aortic balloon pump (IABP) counterpulsation. This case focuses on a patient who had an IABP counterpulsation device inserted following myocardial infarction, requiring urgent coronary artery bypass grafting for acute coronary syndrome. Postoperatively, the IABP could not be removed, with consequent iliac thrombosis and acute limb ischaemia. Emergency femoral-to-femoral crossover bypass was performed using a polytetrafluoroethylene graft. A portion of the IABP balloon tip was entrapped and retained, however, and became the focus of delayed septicaemia, resulting in graft infection and wound breakdown 6 weeks later. Explantation of the residual balloon tip, ligation of the right external iliac artery and redo femoral-femoral crossover using the great saphenous vein were successfully performed.

Preoperative Prophylactic Intraaortic Balloon Pump Reduces the Incidence of Postoperative Acute Kidney Injury and Short-Term Death of High-Risk Patients Undergoing Coronary Artery Bypass Grafting: A Meta-Analysis of 17 Studies

This meta-analysis investigated the effects of preoperative prophylactic intraaortic balloon pump placement on postoperative renal function and short-term death of high-risk patients undergoing coronary artery bypass grafting. We found that preoperative prophylactic intraaortic balloon pump support reduced the incidence of coronary artery bypass grafting-associated acute kidney injury and short-term death and dramatically decreased the incidence of postoperative renal replacement therapy by 82% compared with high-risk patients without the procedure. This is the first meta-analysis to demonstrate significant beneficial effects of preoperative prophylactic intraaortic balloon pump on renal function in high-risk patients undergoing coronary artery bypass grafting.

Renal protection in cardiovascular surgery

Acute kidney injury (AKI) is one of the most relevant complications after major surgery and is a predictor of mortality. In Western countries, patients at risk of developing AKI are mainly those undergoing cardiovascular surgical procedures. In this category of patients, AKI depends on a multifactorial etiology, including low ejection fraction, use of contrast media, hemodynamic instability, cardiopulmonary bypass, and bleeding. Despite a growing body of literature, the treatment of renal failure remains mainly supportive (e.g. hemodynamic stability, fluid management, and avoidance of further damage); therefore, the management of patients at risk of AKI should aim at prevention of renal damage. Thus, the present narrative review analyzes the pathophysiology underlying AKI (specifically in high-risk patients), the preoperative risk factors that predispose to renal damage, early biomarkers related to AKI, and the strategies employed for perioperative renal protection. The most recent scientific evidence has been considered, and whenever conflicting data were encountered possible suggestions are provided.

Temporal Trends of In-Hospital Mortality in Patients Treated with Intra-Aortic Balloon Pumping: A Nationwide Population Study in Taiwan, 1998-2008

Intra-aortic balloon pumping (IABP) is widely used for hemodynamic support in critical patients with cardiogenic shock (CS). We examined whether the in-hospital mortality of patients in Taiwan treated with IABP has recently declined. We used Taiwan’s National Health Insurance Research Database to retrospectively review the in-hospital all-cause mortality of 9952 (7146 men [71.8%]) 18-year-old and older patients treated with IABP between 1998 and 2008. The mortality rate was 13.84% (n = 1377). The urbanization levels of the hospitals, and the number of days in the intensive care unit, of hospitalization, and of IABP treatment, and prior percutaneous coronary intervention (PCI) were associated with mortality. Seven thousand six hundred thirty-five patients (76.72%) underwent coronary artery bypass grafting (CABG) surgery, and 576 (5.79%) underwent high-risk PCI with IABP treatment. The number of patients treated with IABP significantly increased during this decade (p_trend < 0.0001), the in-hospital all-cause mortality for patients treated with IABP significantly decreased (p_trend = 0.0243), but the in-hospital all-cause mortality of patients who underwent CABG and PCI plus IABP did not decrease. In conclusion, the in-hospital mortality rate of IABP treatment decreased annually in Taiwan during the study period. However, high-risk patients who underwent coronary revascularization with IABP had a higher and unstable in-hospital mortality rate.

Intra-aortic balloon pump may grant no benefit to improve the mortality of patients with acute myocardial infarction in short and long term: an updated meta-analysis

Intra-aortic balloon pump (IABP) has been extensively used in clinical practice as a circulatory-assist device. However, current literature demonstrated significantly varied indications for IABP application and prognosis.The objective of the study was to assess the potential benefits or risks of IABP treatment for acute myocardial infarction (AMI) complicated with or without cardiogenic shock.MEDLINE and EMBASE database were systematically searched until November 2014, using the terms as follows: IABP, IABC (intra-aortic balloon counterpulsation), AMI, heart infarction, coronary artery disease, ischemic heart disease, and acute coronary syndrome. Only randomized controlled trials (RCTs) that compared the use of IABP or non-IABP support in AMI with or without cardiogenic shock were included. Two researchers performed data extraction independently, and at the mean time, the risk of bias among those RCTs was also assessed.Of 3026 citations, 17 studies (n = 3226) met the inclusion criteria. There is no significant difference between IABP group and control group on the short-term mortality (relative risk [RR], 0.90; 95% confidence interval [CI], 0.77-1.06; P = 0.214) and long-term mortality (RR, 0.91; 95% CI, 0.79-1.04; P = 0.155) in AMI patients with or without cardiogenic shock. These results were consistent when the analysis was performed on studies that only included patients with cardiogenic shock, both on short-term mortality (RR, 0.91; 95% CI, 0.77-1.08; P = 0.293) and long-term mortality (RR, 0.95; 95% CI, 0.83-1.10; P = 0.492). Similar result was also observed in AMI patients without cardiogenic shock. Furthermore, the risks of hemorrhage (RR, 1.49; 95% CI, 1.09-2.04; P = 0.013) and recurrent ischemia (RR 0.54, 95% CI 0.37 to 0.79; P = 0.002) were significantly higher in IABP group compared with control group.We did not observe substantial benefit from IABP application in reducing the short- and long-term mortality, while it might promote the risks of hemorrhage and recurrent ischemia. Therefore, IABP may be not an optimal therapy in AMI with or without cardiogenic shock until more elaborate classification is used for selecting appropriate patients.

Major themes for 2014 in cardiothoracic and vascular anaesthesia and intensive care

There has been significant progress throughout 2014 in cardiothoracic and vascular anaesthesia and intensive care. There has been a revolution in the clinical approach to acute and chronic adult aortic diseases. Contemporary management of adult aortic disease is based on etiology, clinical presentation, extent, and integrated intervention with medical, endovascular and/or surgical measures. Further European guidelines have explored in depth the cardiovascular management in non-cardiac surgery with a thematic focus to reduce perioperative mortality from the leading offender, namely myocardial ischemia. Integrated guidelines address the management of myocardial revascularization including the percutaneous and surgical options. Despite 50 years since the first coronary artery bypass grafting procedure and impressive advances in interventional cardiology, surgical revascularization remains a gold standard for many patients with coronary artery disease. These advances in 2014 will likely further improve perioperative outcomes for our patients.