The Systemic Inflammatory Response to Cardiopulmonary Bypass

Extended duration of ex-vivo perfusion is associated with worse survival in donation after circulatory death heart recipients: A national database analysis

BACKGROUND

The impact of duration of ex-vivo heart perfusion (EVHP) on patient outcomes following donation after circulatory death (DCD) heart transplantation has not been established.

METHODS

Adult first-time DCD heart transplants using EVHP were identified in the Organ Procurement & Transplant Network database (12/2019-09/2023). Total out of body time (OBT) was dichotomized based on perfusion duration exceeding the 90th percentile of EVHP hearts in the study. The primary outcome of 6-month mortality was assessed using Kaplan Meier curves and multivariable Cox regression. 30-day, 1-year, and 3-year mortality were also assessed. Secondary postoperative outcomes of index hospitalization length of stay, acute rejection, dialysis, and stroke were assessed using univariable linear or logistic regression.

RESULTS

Among 575 recipients of DCD transplantations using EVHP, 58 hearts had extended perfusion times based on an OBT cutoff of 8.3 hours which identified OBT greater than the 90th percentile. Extended perfusion heart recipients had worse overall mortality at 6 months compared to standard perfusion hearts after adjusting for critical donor and recipient factors [aHR = 2.48(1.25,4.93),p = 0.009]. Early 30-day mortality was comparable between the groups (p = 0.592). However, 1-year and 3-year outcomes showed worse mortality in recipients of extended perfusion hearts (both p < 0.05). Post-transplant dialysis requirement and increased length of stay was more likely in the extended perfusion group (both p < 0.05). There was no difference in acute rejection (p = 0.163), and stroke (p = 0.170).

CONCLUSIONS

There is a potential detrimental effect of extended EVHP duration on DCD heart recipient survival. Future work will explore the identified opportunity to improve organ preservation during EVHP.

The Effects of Corticosteroids on Survival in Pediatric and Nonelderly Adult Patients Undergoing Cardiac Surgery: A Meta-analysis of Randomized Studies

OBJECTIVE

Cardiac surgery can be complicated by the development of a systemic inflammatory response syndrome related to cardiopulmonary bypass. This potentially contributes to the occurrence of postoperative morbidity and mortality. Corticosteroids can be used to reduce such inflammation, but the overall balance between potential harm and benefit is unknown and may be age-dependent. The present meta-analysis aims to evaluate the effects of prophylactic corticosteroids in pediatric and non-elderly adult cardiac surgery patients.

DESIGN

Systematic review and meta-analysis of randomized trials.

SETTING

Cardiac surgery with cardiopulmonary bypass.

PARTICIPANTS

Patients younger than 65 years old (pediatric and non-elderly adults).

INTERVENTIONS

Perioperative use of corticosteroids versus placebo or standard care.

MEASUREMENTS AND MAIN RESULTS

Two independent investigators searched PubMed, EMBASE and the Cochrane Library from inception to January 20, 2024. The primary outcome was mortality at the longest follow-up available. Secondary outcomes included acute kidney injury, atrial fibrillation, myocardial injury, cerebrovascular events, and infections. Our search strategy identified a total of 17 randomized trials involving 6,598 patients. Mortality was significantly reduced in the corticosteroid group (78/3321 [2.3%] vs. 116/3277 [3.5%]; risk ratio = 0.69; 95% confidence interval, 0.52 to 0.92; P = 0.01; I2 = 0%; NNT = 91). Moreover, the highest postoperative vasoactive inotropic score (VIS) was significantly lower in corticosteroid group (MD: -2.07, 95% CI -3.69 to -0.45, P = 0.01, I2 = 0%). No significant differences in secondary outcomes between the two treatment groups were recorded.

CONCLUSIONS

This meta-analysis of randomized trials highlights the potential benefits of corticosteroids on survival in cardiac surgery for patients younger than 65 years old.

Prophylactic corticosteroids for infants undergoing cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Prophylactic corticosteroids have been widely used to mitigate the inflammatory response induced by cardiopulmonary bypass (CPB). However, the impact of this treatment on clinically important outcomes in infants remains uncertain.

METHODS

We systematically searched databases (Medline, Embase, and Cochrane Central Register of Controlled Trials), Clinical Trials Registry, and Google Scholar from inception to March 1, 2024. Randomized controlled trials (RCTs) in which infants undergoing on-pump cardiac surgery received prophylactic corticosteroids or placebo were selected. The risk of bias was assessed using the Cochrane Collaboration risk-of-bias tool. Considering clinical heterogeneity between studies, the random-effects model was used for analysis. Subgroup analyses on the neonatal studies and sensitivity analyses by the leave-one-out method were also conducted.

RESULTS

Eight RCTs comprising 1,920 patients were included. Our analysis suggested no significant difference in postoperative mortality (2.1% vs. 3.3%, risk ratio (RR) = 0.71, 95% confidence interval (CI) [0.41, 1.21]). Significantly increased insulin treatment in infants (19.0% vs. 6.5%, RR = 2.78, 95% CI [2.05, 3.77]) and significantly reduced duration of mechanical ventilation in neonates (mean difference = -22.28 h, 95% CI [-42.58, -1.97]) were observed in the corticosteroids group. There were no differences between groups for postoperative acute kidney injury, cardiac arrest, extracorporeal membrane oxygenation support, low cardiac output syndrome, neurologic events, infection, or length of postoperative intensive care unit stay.

CONCLUSIONS

Current evidence does not support the routine prophylactic use of corticosteroids in infants undergoing cardiac surgery with CPB. Further large-scale research is needed to investigate the optimal agent, dosing regimen, and specific impact on various types of cardiac surgery.

TRIAL REGISTRATION

This systematic review and meta-analysis was registered at the International Prospective Register of Systematic Reviews (CRD42023400176).

Development and validation of a machine learning predictive model for perioperative myocardial injury in cardiac surgery with cardiopulmonary bypass

BACKGROUND

Perioperative myocardial injury (PMI) with different cut-off values has showed to be associated with different prognostic effect after cardiac surgery. Machine learning (ML) method has been widely used in perioperative risk predictions during cardiac surgery. However, the utilization of ML in PMI has not been studied yet. Therefore, we sought to develop and validate the performances of ML for PMI with different cut-off values in cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

This was a second analysis of a multicenter clinical trial (OPTIMAL) and requirement for written informed consent was waived due to the retrospective design. Patients aged 18-70 undergoing elective cardiac surgery with CPB from December 2018 to April 2021 were enrolled in China. The models were developed using the data from Fuwai Hospital and externally validated by the other three cardiac centres. Traditional logistic regression (LR) and eleven ML models were constructed. The primary outcome was PMI, defined as the postoperative maximum cardiac Troponin I beyond different times of upper reference limit (40x, 70x, 100x, 130x) We measured the model performance by examining the area under the receiver operating characteristic curve (AUROC), precision-recall curve (AUPRC), and calibration brier score.

RESULTS

A total of 2983 eligible patients eventually participated in both the model development (n = 2420) and external validation (n = 563). The CatboostClassifier and RandomForestClassifier emerged as potential alternatives to the LR model for predicting PMI. The AUROC demonstrated an increase with each of the four cutoffs, peaking at 100x URL in the testing dataset and at 70x URL in the external validation dataset. However, it's worth noting that the AUPRC decreased with each cutoff increment. Additionally, the Brier loss score decreased as the cutoffs increased, reaching its lowest point at 0.16 with a 130x URL cutoff. Moreover, extended CPB time, aortic duration, elevated preoperative N-terminal brain sodium peptide, reduced preoperative neutrophil count, higher body mass index, and increased high-sensitivity C-reactive protein levels were identified as risk factors for PMI across all four cutoff values.

CONCLUSIONS

The CatboostClassifier and RandomForestClassifer algorithms could be an alternative for LR in prediction of PMI. Furthermore, preoperative higher N-terminal brain sodium peptide and lower high-sensitivity C-reactive protein were strong risk factor for PMI, the underlying mechanism require further investigation.

Predictors of early peritoneal dialysis initiation in newborns and young infants following cardiac surgery

OBJECTIVE

This single-centre, retrospective cohort study was conducted to investigate the predictors of early peritoneal dialysis initiation in newborns and young infants undergoing cardiac surgery.

METHODS

There were fifty-seven newborns and young infants. All subjects received peritoneal dialysis catheter after completion of the cardiopulmonary bypass. Worsening post-operative (post-op) positive fluid balance and oliguria (<1 ml/kg/hour) despite furosemide were the clinical indications to start early peritoneal dialysis (peritoneal dialysis +). Demographic, clinical, and laboratory data were collected from the pre-operative, intra-operative, and immediately post-operative periods.

RESULTS

Baseline demographic data were indifferent except that peritoneal dialysis + group had more newborns. Pre-operative serum creatinine was higher for peritoneal dialysis + group (p = 0.025). Peritoneal dialysis + group had longer cardiopulmonary bypass time (p = 0.044), longer aorta cross-clamp time (p = 0.044), and less urine output during post-op 24 hours (p = 0.008). In the univariate logistic regression model, pre-op serum creatinine was significantly associated with higher odds of being in peritoneal dialysis + (p = 0.021) and post-op systolic blood pressure (p = 0.018) and post-op mean arterial pressure (p=0.001) were significantly associated with reduced odds of being in peritoneal dialysis + (p = 0.018 and p = 0.001, respectively). Post-op mean arterial pressure showed a statistically significant association adjusted odds ratio = 0.89, 95% confidence interval [0.81, 0.96], p = 0.004) with peritoneal dialysis + in multivariate analysis after adjusting for age at surgery.

CONCLUSIONS

In our single-centre cohort, pre-op serum creatinine, post-op systolic blood pressure, and mean arterial pressure demonstrated statistically significant association with peritoneal dialysis +. This finding may help to better risk stratify newborns and young infants for early peritoneal dialysis start following cardiac surgery.

Hybrid feature selection in a machine learning predictive model for perioperative myocardial injury in noncoronary cardiac surgery with cardiopulmonary bypass

BACKGROUND

Perioperative myocardial injury (PMI) is associated with increased mobility and mortality after noncoronary cardiac surgery. However, limited studies have developed a predictive model for PMI. Therefore, we used hybrid feature selection (FS) methods to establish a predictive model for PMI in noncoronary cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

This was a single-center retrospective study conducted at the Fuwai Hospital in China. Patients aged 18-70 years who underwent elective noncoronary surgery with CPB at our institution from December 2018 to April 2021 were enrolled. The primary outcome was PMI, defined as the postoperative cardiac troponin I (cTnI) levels exceeding 220 times of upper reference limit (URL). Statistical analyses were conducted by Python (Python Software Foundation, version 3.9.7 and integrated development environment Jupyter Notebook 1.1.0) and SPSS software version 26.0 (IBM Corp., Armonk, New York, USA).

RESULTS

A total of 1130 patients were eventually eligible for this study. The incidence of PMI was 20.3% (229/1130) in the overall patients, 20.6% (163/791) in the training dataset, and 19.5% (66/339) in the testing dataset. The logistic regression model performed the best AUC of 0.6893 (95 CI%: 0.6371-0.7382) by the traditional selection method, and the random forest model performed the best AUC of 0.6937 (95 CI%: 0.6416-0.7423) by the union of Wrapper and Embedded method, and the CatBoost model performed the best AUC of 0.6828 (95 CI%: 0.6304-0.7320) by the union of Embedded and forward logistic regression technique, and the Naïve Bayes model achieved the best AUC with 0.7254 (95 CI%: 0.6746-0.7723) by forwarding logistic regression method. Moreover, the decision tree, KNeighborsClassifier, and support vector machine models performed the worse AUC in all selection forms. Furthermore, the SHapley Additive exPlanations plot showed that prolonged CPB, aortic clamp time, and preoperative low platelets count were strongly related to the PMI risk.

CONCLUSIONS

In total, four category feature selection methods were utilized, comprising five individual selection techniques and 15 combined methods. Notably, the combination of logistic regression and embedded methods demonstrated outstanding performance in predicting PMI risk. We also concluded that the machine learning model, including random forest, catboost, and Naive Bayes, were suitable candidates for establishing PMI predictive model. Nevertheless, additional investigation and validation are imperative for substantiating these finding.

Prevention of Atrial Fibrillation After Cardiac Surgery: A Review of Literature and Comparison of Different Treatment Modalities

Atrial fibrillation is the most common arrhythmia to occur after cardiac surgery, with an incidence of 10% to 50%. It is associated with postoperative complications including increased risk of stroke, prolonged hospital stays and increased costs. Despite new insights into the mechanisms of atrial fibrillation, no specific etiologic factor has been identified as the sole perpetrator of the arrhythmia. Current evidence suggests that the pathophysiology of atrial fibrillation in general, as well as after cardiac surgery, is multifactorial. Studies have also shown that new-onset postoperative atrial fibrillation following cardiac surgery is associated with a higher risk of short-term and long-term mortality. Furthermore, it has been demonstrated that prophylactic medical therapy decreases the incidence of postoperative atrial fibrillation after cardiac surgery. Of note, the incidence of postoperative atrial fibrillation has not changed during the last decades despite the numerous preventive strategies and operative techniques proposed, although the perioperative and postoperative care of cardiac patients as such has improved.

Effects of RBT-1 on preconditioning response biomarkers in patients undergoing coronary artery bypass graft or heart valve surgery: a multicentre, double-blind, randomised, placebo-controlled phase 2 trial

Background

RBT-1 is a combination drug of stannic protoporfin (SnPP) and iron sucrose (FeS) that elicits a preconditioning response through activation of antioxidant, anti-inflammatory, and iron-scavenging pathways, as measured by heme oxygenase-1 (HO-1), interleukin-10 (IL-10), and ferritin, respectively. Our primary aim was to determine whether RBT-1 administered before surgery would safely and effectively elicit a preconditioning response in patients undergoing cardiac surgery.

Methods

This phase 2, double-blind, randomised, placebo-controlled, parallel-group, adaptive trial, conducted in 19 centres across the USA, Canada, and Australia, enrolled patients scheduled to undergo non-emergent coronary artery bypass graft (CABG) and/or heart valve surgery with cardiopulmonary bypass. Patients were randomised (1:1:1) to receive either a single intravenous infusion of high-dose RBT-1 (90 mg SnPP/240 mg FeS), low-dose RBT-1 (45 mg SnPP/240 mg FeS), or placebo within 24-48 h before surgery. The primary outcome was a preoperative preconditioning response, measured by a composite of plasma HO-1, IL-10, and ferritin. Safety was assessed by adverse events and laboratory parameters. Prespecified adaptive criteria permitted early stopping and enrichment. This trial is registered with ClinicalTrials.gov, NCT04564833.

Findings

Between Aug 4, 2021, and Nov 9, 2022, of 135 patients who were enrolled and randomly allocated to a study group (46 high-dose, 45 low-dose, 44 placebo), 132 (98%) were included in the primary analysis (46 high-dose, 42 low-dose, 44 placebo). At interim, the trial proceeded to full enrollment without enrichment. RBT-1 led to a greater preconditioning response than did placebo at high-dose (geometric least squares mean [GLSM] ratio, 3.58; 95% CI, 2.91-4.41; p < 0.0001) and low-dose (GLSM ratio, 2.62; 95% CI, 2.11-3.24; p < 0.0001). RBT-1 was generally well tolerated by patients. The primary drug-related adverse event was dose-dependent photosensitivity, observed in 12 (26%) of 46 patients treated with high-dose RBT-1 and in six (13%) of 45 patients treated with low-dose RBT-1 (safety population).

Interpretation

RBT-1 demonstrated a statistically significant cytoprotective preconditioning response and a manageable safety profile. Further research is needed. A phase 3 trial is planned.

Funding

Renibus Therapeutics, Inc.

Recombinant Activated Factor VII (rFVIIa) for Bleeding After Thoracic Aortic Surgery: A Scoping Review of Current Literature

BACKGROUND

Bleeding after surgery on the thoracic aorta is a frequent complication, and can be associated with a significant increase in morbidity and mortality. Recombinant activated factor VII (rFVIIa) was developed initially for treating patients with hemophilia; however, it has been used increasingly "off-label" to achieve hemostasis after thoracic aortic procedures.

OBJECTIVE

This scoping review aimed to present the available literature on the role of rFVIIa in the management of refractory postoperative bleeding after thoracic aortic surgery.

METHODS/RESULTS

An electronic database search was conducted using Medline, Embase, Cochrane Library, and Google Scholar in June 2023. The authors included studies that reported the use of rFVIIa in patients undergoing surgical repair of ascending or descending aortic aneurysm or dissection. Single-case reports were excluded. Ten publications with a pooled number of 649 patients (319 patients received rFVIIa and 330 in the control groups) were identified: 3 case series, 6 retrospective studies, and 1 nonrandomized clinical trial. All studies reported the potential role of rFVIIa in correcting coagulopathy and reducing postoperative blood loss in this group of patients. Overall, there was not enough evidence to suggest that rFVIIa was associated with higher rates of thromboembolic complications or mortality.

CONCLUSION

Limited evidence suggests that rFVIIa may be useful in managing postoperative refractory bleeding in patients undergoing thoracic aortic surgery. However, the impact of rFVIIa on thromboembolic complications and mortality rates remains unclear.

Inflammation risk before cardiac surgery and the treatment effect of intraoperative dexamethasone

Patients who exhibit high systemic inflammation after cardiac surgery may benefit most from pre-emptive anti-inflammatory treatments. In this secondary analysis (n = 813) of the randomised, double-blind Intraoperative High-Dose Dexamethasone for Cardiac Surgery trial, we set out to develop an inflammation risk prediction model and assess whether patients at higher risk benefit from a single intraoperative dose of dexamethasone (1 mg/kg). Inflammation risk before surgery was quantified from a linear regression model developed in the placebo arm, relating preoperatively available covariates to peak postoperative C-reactive protein. The primary endpoint was the interaction between inflammation risk and the peak postoperative C-reactive protein reduction associated with dexamethasone treatment. The impact of dexamethasone on the main clinical outcome (a composite of death, myocardial infarction, stroke, renal failure, or respiratory failure within 30 days) was also explored in relation to inflammation risk. Preoperatively available covariates explained a minority of peak postoperative C-reactive protein variation and were not suitable for clinical application (R2 = 0.058, P = 0.012); C-reactive protein before surgery (excluded above 10 mg/L) was the most predictive covariate (P < 0.001). The anti-inflammatory effect of dexamethasone increased as the inflammation risk increased (-0.689 mg/L per unit predicted peak C-reactive protein, P = 0.002 for interaction). No treatment-effect heterogeneity was detected for the main clinical outcome (P = 0.167 for interaction). Overall, risk predictions from a model of inflammation after cardiac surgery were associated with the degree of peak postoperative C-reactive protein reduction derived from dexamethasone treatment. Future work should explore the impact of this phenomenon on clinical outcomes in larger surgical populations.

Utility of heparin-binding protein following cardiothoracic surgery using cardiopulmonary bypass

Cardiothoracic surgery using cardiopulmonary bypass (CPB) triggers an inflammatory state that may be difficult to differentiate from infection. Heparin-binding protein (HBP) is a candidate biomarker for sepsis. As data indicates that HBP normalizes rapidly after cardiothoracic surgery, it may be a suitable early marker of postoperative infection. We therefore aimed to investigate which variables influence postoperative HBP levels and whether elevated HBP concentration is associated with poor surgical outcome. This exploratory, prospective, observational study enrolled 1475 patients undergoing cardiothoracic surgery using CPB, where HBP was measured at ICU arrival. Patients with HBP in the highest tercile were compared to remaining patients. Multivariable logistic regressions were performed to identify factors predictive of elevated HBP and 30-day mortality. Overall median HBP was 30.0 ng/mL. Patients undergoing isolated CABG or surgery with CPB-duration ≤ 60 min had a median HBP of 24.9 ng/mL and 23.2 ng/mL, respectively. Independent predictors of elevated postoperative HBP included increased EuroSCORE, prolonged CPB-duration and high intraoperative temperature. Increased HBP was an independent predictor of 30-day mortality. This study confirms the promising characteristics of HBP as a biomarker for identification of postoperative sepsis, especially after routine procedures. Further studies are required to investigate whether HBP may detect postoperative infections.

Positive End-Expiratory Pressure in Rhinoplasty Surgery; Risks and Benefits

Aims

The aim of this study is to evaluate the effect of Positive End Expiratory Pressure (PEEP) on surgical field bleeding and its respiratory and hemodynamic consequences in rhinoplasty surgeries.

Materials and methods

This single-blind clinical trial performed in Amir Al-Momenin university Hospital in 2018. Seventy cases of rhinoplasty surgery patients Enrolled and were randomized into two groups; intervention (PEEP = 5) and comparison group (PEEP = 0). Surgical field bleeding and arterial oxygen saturation pulmonary dynamics and hemodynamic parameters were evaluated during operation and in post anesthesia care unit. Data were analyzed by SPSS software using descriptive and analytical statistics.

Results

PEEP applying had no negative effect on surgical bleeding as well as surgeon satisfaction, heart rate and blood pressure were similar in two groups. Pulmonary dynamics and oxygenation were stable and within normal values in all cases. The mean peak airway pressure was 17.87 ± 2.24 in the PEEP group and 16.08 ± 3.37 in the ZEEP group (P = 0.029).

Conclusion

applying low level PEEP during anesthesia improved recovery oxygen saturation but had no negative effects on the patient`s hemodynamics, and did not aggravate bleeding and visual clarity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03854-7.

Haemodynamic effects of prophylactic post-operative hydrocortisone following cardiopulmonary bypass in neonates undergoing cardiac surgery

Multiple studies have endeavoured to define the role of steroids in paediatric congenital heart surgery; however, steroid utilisation remains haphazard. In September, 2017, our institution implemented a protocol requiring that all neonates undergoing cardiac surgery with the use of cardiopulmonary bypass receive a five-day post-operative hydrocortisone taper. This single-centre retrospective study was designed to test the hypothesis that routine post-operative hydrocortisone administration reduces the incidence of capillary leak syndrome, leads to favourable postoperative fluid balance, and less inotropic support in the early post-operative period. Data were gathered on all term neonates who underwent cardiac surgery with the use of bypass between September, 2015 and 2019. Subjects who were unable to separate from bypass, required long-term dialysis, or long-term mechanical ventilation were excluded. Seventy-five patients met eligibility criteria (non-hydrocortisone group = 52; hydrocortisone group = 23). For post-operative days 0-4, we did not observe a significant difference in net fluid balance or vasoactive inotropic score between study groups. Similarly, we saw no major difference in secondary clinical outcomes (post-operative duration of mechanical ventilation, ICU/hospital length of stay, and time from surgery to initiation of enteral feeds). In contrast to prior analyses, our study was unable to demonstrate a significant difference in net fluid balance or vasoactive inotropic score with the administration of a tapered post-operative hydrocortisone regimen. Similarly, we saw no effect on secondary clinical outcomes. Further long-term randomised control studies are necessary to validate the potential clinical benefit of utilising steroids in paediatric cardiac surgery, especially in the more fragile neonatal population.

Pulmonary reperfusion injury in post-palliative intervention of oligaemic cyanotic CHD: a new catastrophic consequence or just revisiting the same old story?

Pulmonary reperfusion injury is a well-recognised clinical entity in the setting pulmonary artery angioplasty for pulmonary artery stenosis or chronic thromboembolic disease, but not much is known about this complication in post-palliative intervention of oligaemic cyanotic CHD. The pathophysiology of pulmonary reperfusion injury in this population consists of both ischaemic and reperfusion injury, mainly resulting in oxidative stress from reactive oxygen species generation, followed by endothelial dysfunction, and cytokine storm that may induce multiple organ dysfunction. Other mechanisms of pulmonary reperfusion injury are "no-reflow" phenomenon, overcirculation from high pressure in pulmonary artery, and increased left ventricular end-diastolic pressure. Chronic hypoxia in cyanotic CHD eventually depletes endogenous antioxidant and increased the risk of pulmonary reperfusion injury, thus becoming a concern for palliative interventions in the oligaemic subgroup. The incidence of pulmonary reperfusion injury varies depending on multifactors. Despite its inconsistence occurrence, pulmonary reperfusion injury does occur and may lead to morbidity and mortality in this population. The current management of pulmonary reperfusion injury is supportive therapy to prevent deterioration of lung injury. Therefore, a general consensus on pulmonary reperfusion injury is necessary for the diagnosis and management of this complication as well as further studies to establish the use of novel and potential therapies for pulmonary reperfusion injury.

Comparison of Prothrombin Complex Concentrate with Activated Factor VII Use for Bleeding Following Cardiopulmonary Bypass in Children

OBJECTIVE

This study aims to compare the efficacy and safety of activated recombinant factor VII (rFVIIa) and prothrombin complex concentrate (PCC) in the treatment of bleeding complications following surgery requiring cardiopulmonary bypass (CPB) in children.

DESIGN/METHODS

This is a retrospective chart review of a single institution comprising patients aged 0 to 18 years old with congenital heart disease. Patients must have received either PCC or rFVIIa after coming off CPB. Our primary efficacy endpoint is time in the operating room from off-CPB to pediatric intensive care unit admission. Our primary safety endpoint is thrombosis through 30 days.

RESULTS

Our primary efficacy outcome was significantly shorter in the PCC group compared with the rFVIIa group (P < .0001). Similarly, secondary efficacy outcomes of packed red blood cell administration, chest tube output, and transfusion exposures all significantly favored PCC administration. However, CPB time was significantly longer, and body temperatures were significantly lower, in the rFVIIa group. Safety outcomes, including our primary safety outcome of thrombosis through 30 days, were similar between the two groups.

CONCLUSION

This study questions whether PCC could be favored over rFVIIa for hemostasis in children with congenital heart disease following CPB surgery. In addition, this study has found no difference when comparing PCC and rFVIIa in terms of safety outcomes, particularly thrombosis events. There are several limitations to this study due to the retrospective nature of the design and the differences between the two study groups. Despite the limitations, this study suggests that relatively early administration of PCC could be favored over delayed administration of rFVIIa to control recalcitrant post-CPB bleeding in the operating room.

Lung injury following cardiopulmonary bypass: a clinical update

INTRODUCTION

Cardiopulmonary bypass (CPB) is an integral component of cardiac surgery; however, one of its most critical complications is acute lung injury induced by multiple factors including systemic inflammatory response.

AREAS COVERED

The objective of this review is to investigate the multiple factors that can lead to CPB-induced lung injury. These include contact of blood components with the artificial surface of the CPB circuit, local and systemic inflammatory response syndrome (SIRS), lung ischemia/re-perfusion injury, arrest of ventilation, and circulating endotoxins. We also focus on possible interventions to curtail the negative impact of CPB, such as off-pump surgery, impregnation of the circuit with less biologically active substances, leukocyte depletion filters and ultrafiltration, and pharmacological agents such as steroids and aprotinin.

EXPERT OPINION

Although many aspects of CPB are proposed to contribute to lung injury, its overall role is still not clear. Multiple interventions have been introduced to reduce the risk of pulmonary dysfunction, with many of these interventions having shown promising results, significantly attenuating inflammatory mediators and improving post-operative outcome. However, since lung injury is multifactorial and affected by inextricably linked components, multiple interventions tackling each of them is required.

Vasoplegic Syndrome after Cardiopulmonary Bypass in Cardiovascular Surgery: Pathophysiology and Management in Critical Care

Vasoplegic syndrome (VS) is a common complication following cardiovascular surgery with cardiopulmonary bypass (CPB), and its incidence varies from 5 to 44%. It is defined as a distributive form of shock due to a significant drop in vascular resistance after CPB. Risk factors of VS include heart failure with low ejection fraction, renal failure, pre-operative use of angiotensin-converting enzyme inhibitors, prolonged aortic cross-clamp and left ventricular assist device surgery. The pathophysiology of VS after CPB is multi-factorial. Surgical trauma, exposure to the elements of the CPB circuit and ischemia-reperfusion promote a systemic inflammatory response with the release of cytokines (IL-1β, IL-6, IL-8, and TNF-α) with vasodilating properties, both direct and indirect through the expression of inducible nitric oxide (NO) synthase. The resulting increase in NO production fosters a decrease in vascular resistance and a reduced responsiveness to vasopressor agents. Further mechanisms of vasodilation include the lowering of plasma vasopressin, the desensitization of adrenergic receptors, and the activation of ATP-dependent potassium (KATP) channels. Patients developing VS experience more complications and have increased mortality. Management includes primarily fluid resuscitation and conventional vasopressors (catecholamines and vasopressin), while alternative vasopressors (angiotensin 2, methylene blue, hydroxocobalamin) and anti-inflammatory strategies (corticosteroids) may be used as a rescue therapy in deteriorating patients, albeit with insufficient evidence to provide any strong recommendation. In this review, we present an update of the pathophysiological mechanisms of vasoplegic syndrome complicating CPB and discuss available therapeutic options.

CABG in patients with liver cirrhosis: to pump or not to pump?

INTRODUCTION

Coronary artery bypass grafting in patients with established liver cirrhosis is generally associated with poor outcomes. Avoiding cardiopulmonary bypass (CPB) in these patients has not demonstrated any advantage over the use of CPB. We review the current available literature that compared the outcome of both on-pump (ONCABG) and off-pump (OPCAB) techniques in cirrhotic patients in terms of morbidity and mortality.

AREAS COVERED

A comprehensive search was conducted in the PubMed/MEDLINE and EMBASE databases in January 2021. Articles that reported outcomes of OPCAB and/or ONCABG in cirrhotic patients with no concomitant surgical procedures were included. 829 unique abstracts were retrieved with title and abstract screening completed independently by two reviewers. Two case studies and six retrospective cohort studies were included. The largest study comprised more than 98% of the total population, showing some survival benefit for OPCAB over ONCABG. However, it was population-based and did not report the severity of liver. The remaining studies reported no clear difference in outcome between the two techniques.

EXPERT OPINION

: Surgical myocardial revascularisation carries high peri-operative risk in patients with liver cirrhosis irrespective of the surgical technique. There is a lack of evidence to suggest that avoiding CPB in these patients may be beneficial.

Impact of Systemic Inflammatory Response Syndrome on Clinical, Echocardiographic, and Computed Tomographic Outcomes Among Patients Undergoing Transcatheter Aortic Valve Implantation

Background

Systemic inflammatory response syndrome (SIRS) is a systemic insult that has been described with many interventional cardiac procedures. The outcomes of patients undergoing transcatheter aortic valve implantation (TAVI) are thought to be influenced by this syndrome not only on short-term, but also on long-term.

Objective

We assessed the association of SIRS to different clinical, echocardiographic, and computed tomographic (CT) outcomes after TAVI.

Methods

Two hundred and twenty-four consecutive patients undergoing TAVI were enrolled in this study. They were assessed for the occurrence of SIRS within the first 48 h after TAVI. Patients were followed-up for short- and long-term clinical outcomes. Serial echocardiographic follow-ups were conducted at 1-week, 6-months, and 1-year. CT follow-up at 1 year was recorded.

Results

Eighty patients (36%) developed SIRS. Among different parameters, only pre-TAVI total leucocytic count (TLC), pre-TAVI heart rate, and post-TAVI systolic blood pressure independently predicted the occurrence of SIRS. The incidence of HALT was not significantly different between both groups, albeit higher among SIRS patients (p = 0.1) at 1-year CT follow-up. Both groups had similar patterns of LV recovery on serial echocardiography. Long-term follow-up showed that all-cause death, cardiac death, and re-admission for heart failure (HF) or acute coronary syndrome (ACS) were significantly more frequent among SIRS patients. Early safety and clinical efficacy outcomes were more frequently encountered in the SIRS group, while device-related events and time-related valve safety were comparable.

Conclusion

Although SIRS implies an early acute inflammatory status post-TAVI, yet its clinical sequelae seem to extend to long-term clinical outcomes.

Cardiac surgery improves the postoperative frailty score of frail patients

BACKGROUND

Cardiac surgery in frail patients has been reported to be associated with increased mortality and morbidity but may improve functional status of frail patients. Few studies have investigated the impact of cardiac surgery on the trajectory of postoperative frailty. We hypothesized that cardiac surgery in frail patients would improve frailty postoperatively.

METHOD

This study included 71 patients over 65 years old who were scheduled for cardiac surgery via sternotomy or thoracotomy. Frailty was prospectively evaluated using the Kihon Checklist (KCL) at 1 and 3 months postoperatively. Patients were divided into three groups based on the preoperative KCL score: nonfrail, prefrail, and frail. The interaction between the degree of preoperative frailty and the trajectory of postoperative KCL scores was assessed.

RESULTS

The KCL score changed significantly over time (P < 0.001), and the KCL score trajectory differed significantly according to the degree of preoperative frailty (P for interaction = 0.003). In the frail group, the KCL score was significantly lower 3 months postoperatively than preoperatively (median 8, interquartile range [5, 9] versus median 9, interquartile range (9, 13), P = 0.029).

CONCLUSION

The trajectory of postoperative KCL scores differed significantly depending on the degree of preoperative frailty. At 3 months after cardiac surgery, the KCL score of frail patients was significantly improved, while that in nonfrail patients was significantly deteriorated.

Renal and Cerebral Hypoxia and Inflammation During Cardiopulmonary Bypass

Cardiac surgery-associated acute kidney injury and brain injury remain common despite ongoing efforts to improve both the equipment and procedures deployed during cardiopulmonary bypass (CPB). The pathophysiology of injury of the kidney and brain during CPB is not completely understood. Nevertheless, renal (particularly in the medulla) and cerebral hypoxia and inflammation likely play critical roles. Multiple practical factors, including depth and mode of anesthesia, hemodilution, pump flow, and arterial pressure can influence oxygenation of the brain and kidney during CPB. Critically, these factors may have differential effects on these two vital organs. Systemic inflammatory pathways are activated during CPB through activation of the complement system, coagulation pathways, leukocytes, and the release of inflammatory cytokines. Local inflammation in the brain and kidney may be aggravated by ischemia (and thus hypoxia) and reperfusion (and thus oxidative stress) and activation of resident and infiltrating inflammatory cells. Various strategies, including manipulating perfusion conditions and administration of pharmacotherapies, could potentially be deployed to avoid or attenuate hypoxia and inflammation during CPB. Regarding manipulating perfusion conditions, based on experimental and clinical data, increasing standard pump flow and arterial pressure during CPB appears to offer the best hope to avoid hypoxia and injury, at least in the kidney. Pharmacological approaches, including use of anti-inflammatory agents such as dexmedetomidine and erythropoietin, have shown promise in preclinical models but have not been adequately tested in human trials. However, evidence for beneficial effects of corticosteroids on renal and neurological outcomes is lacking. © 2021 American Physiological Society. Compr Physiol 11:1-36, 2021.

Conventional versus miniaturized cardiopulmonary bypass: A systematic review and meta-analysis

Objective

A meta-analysis of randomized controlled trials was performed to compare the effects of miniaturized extracorporeal circulation (MECC) and conventional extracorporeal circulation (CECC) on morbidity and mortality rates after cardiac surgery.

Methods

A comprehensive literature search was conducted using Ovid, PubMed, Medline, EMBASE, and the Cochrane databases. Randomized controlled trials from the year 2000 with n > 40 patients were considered. Key search terms included variations of "mini," "cardiopulmonary," "bypass," "extracorporeal," "perfusion," and "circuit." Studies were assessed for bias using the Cochrane Risk of Bias tool. The primary outcomes were postoperative mortality and stroke. Secondary outcomes included arrhythmia, myocardial infarction, renal failure, blood loss, and a composite outcome comprised of mortality, stroke, myocardial infarction and renal failure. Duration of intensive care unit, and hospital stay was also recorded.

Results

The 42 studies eligible for this study included a total of 2154 patients who underwent CECC and 2196 patients who underwent MECC. There were no significant differences in any preoperative or demographic characteristics. Compared with CECC, MECC did not reduce the incidence of mortality, stroke, myocardial infarction, and renal failure but did significantly decrease the composite of these outcomes (odds ratio, 0.64; 95% confidence interval [CI], 0.50-0.81; P = .0002). MECC was also associated with reductions in arrhythmia (odds ratio, 0.67; 95% CI, 0.54-0.83; P = .0003), blood loss (mean difference [MD], -96.37 mL; 95% CI, -152.70 to -40.05 mL; P = .0008), hospital stay (MD, -0.70 days; 95% CI, -1.21 to -0.20 days; P = .006), and intensive care unit stay (MD, -2.27 hours; 95% CI, -3.03 to -1.50 hours; P < .001).

Conclusions

MECC demonstrates clinical benefits compared with CECC. Further studies are required to perform a cost-utility analysis and to assess the long-term outcomes of MECC. These should use standardized definitions of endpoints such as mortality and renal failure to reduce inconsistency in outcome reporting.

C-reactive protein and procalcitonin after congenital heart surgery utilizing cardiopulmonary bypass: When should we be worried?

INTRODUCTION

To assess the efficacy of C-reactive protein (CRP) and procalcitonin (PCT) at identifying infection in children after congenital heart surgery (CHS) with cardiopulmonary bypass (CPB).

MATERIALS AND METHODS

Systematic review of the literature was conducted to identify studies with data regarding CRP and/or PCT after CHS with CPB. The primary variables identified to be characterized were CRP and PCT at different timepoints. The main inclusion criteria were children who underwent CHS with CPB. Subset analyses for those with and without documented infection were conducted in similar fashion. A p value of less than .05 was considered statistically significant.

RESULTS

A total of 21 studies were included for CRP with 1655 patients and a total of 9 studies were included for PCT with 882 patients. CRP peaked on postoperative Day 2. A significant difference was noted in those with infection only on postoperative Day 4 with a level of 53.60 mg/L in those with documented infection versus 29.68 mg/L in those without. PCT peaked on postoperative Day 2. A significant difference was noted in those with infection on postoperative Days 1, 2, and 3 with a level of 12.9 ng/ml in those with documented infection versus 5.6 ng/ml in those without.

CONCLUSIONS

Both CRP and PCT increase after CHS with CPB and peak on postoperative day 2. PCT has a greater statistically significant difference in those with documented infection when compared to CRP and a PCT of greater than 5.6 ng/ml should raise suspicion for infection.

Angiotensin II: A Review of Current Literature

Up to one-third of all patients admitted to intensive care units carry a diagnosis of shock. The use of angiotensin II is becoming widespread in all forms of shock, including cardiogenic, after the U.S. Food and Drug Administration's (FDA's) initial approval for vasoplegic shock in 2017. Here, the authors review the literature on angiotensin II's mechanism of action, benefits, and future therapeutic opportunities.

The Use of Colchicine in Cardiovascular Diseases: A Systematic Review

The medicinal properties of colchicine have been recognized for centuries. Although previously used for gout and familial Mediterranean fever, its immune-modulating, anti-inflammatory, and antifibrotic effects are increasingly recognized as beneficial in the treatment of cardiovascular disorders. In this systematic review, we summarize the current evidence on colchicine's effectiveness in 1) pericarditis, 2) coronary artery disease, and 3) atrial fibrillation. We also discuss the safety, potential adverse effects, and common drug interactions that should be considered during use.

New-onset acute rapidly deteriorating case of calciphylaxis after open heart surgery: a case report

Background 

Calciphylaxis is a rare life-threatening condition that is characterized by calcification of small blood vessels and soft tissues. This condition is classically described in uraemic patients with end-stage renal failure who are on dialysis or had previous renal transplant. It has also been reported in non-uraemic patients and those who are on warfarin therapy. It is typically associated with high calcium/phosphorus product. Patients classically present with painful skin lesion that evolve into painful ulcers. There are multiple risk factors that were reported to trigger or worsen calciphylaxis. Treatment is a multidisciplinary approach that involves elimination of risk factors, wound management, pain control, and optimization of calcium/phosphorus metabolism. Reported mortality rates are very high especially in the uraemic group.

Case summary 

Here we present a case of a patient, who is on chronic renal dialysis for stage renal failure, who underwent mechanical mitral valve replacement and tricuspid valve repair. In the perioperative period, she was exposed to multiple risk factors that are known to potentially trigger prophylaxis. In the early postoperative period, she developed new-onset rapidly deteriorating skin lesions and the histopathological diagnosis confirmed calciphylaxis. Her treatment plan included pain control, frequent wound care, and optimization of nutritional and metabolic status.

Discussion 

Calciphylaxis is a very serious condition that is usually associated with poor outcome. In this case, we discuss the unusual presentation of this condition with particular emphasis on the multiple perioperative risk factors that can potentially trigger the onset of calciphylaxis in postoperative cardiac patients. We also discuss the epidemiology, pathogenesis, diagnosis, histopathological findings, and different lines of treatment of this serious condition and the potential preventative strategies.

Managing the coagulopathy associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has allowed for significant surgical advancements, but accompanying risks can be significant and must be expertly managed. One of the foremost risks is coagulopathic bleeding. Increasing levels of bleeding in cardiac surgical patients at the time of separation from CPB are associated with poor outcomes and mortality. CPB-associated coagulopathy is typically multifactorial and rarely due to inadequate reversal of systemic heparin alone. The components of the bypass circuit induce systemic inflammation and multiple disturbances of the coagulation and fibrinolytic systems. Anticipating coagulopathy is the first step in managing it, and specific patient and procedural risk factors have been identified as predictors of excessive bleeding. Medication management pre-procedure is critical, as patients undergoing cardiac surgery are commonly on anticoagulants or antiplatelet agents. Important adjuncts to avoid transfusion include antifibrinolytics, and perfusion practices such as red cell salvage, sequestration, and retrograde autologous priming of the bypass circuit have varying degrees of evidence supporting their use. Understanding the patient's coagulation status helps target product replacement and avoid larger volume transfusion. There is increasing recognition of the role of point-of-care viscoelastic and functional platelet testing. Common pitfalls in the management of post-CPB coagulopathy include overdosing protamine for heparin reversal, imperfect laboratory measures of thrombin generation that result in normal or near-normal laboratory results in the presence of continued bleeding, and delayed recognition of surgical bleeding. While challenging, the effective management of CPB-associated coagulopathy can significantly improve patient outcomes.

The Dynamics of Heparin-Binding Protein in Cardiothoracic Surgery-A Pilot Study

OBJECTIVES

To explore the preoperative, intraoperative, and postoperative dynamics of heparin-binding protein (HBP) in cardiothoracic surgery.

DESIGN

This was a prospective, observational study.

SETTING

The study was conducted at a single university hospital.

PARTICIPANTS

Thirty patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) were included, 15 of whom underwent coronary artery bypass grafting surgery and 15 of whom underwent complex procedures. Ten patients undergoing lung surgery also were included as a conventional surgery reference group.

INTERVENTIONS

No interventions were performed.

MEASUREMENTS AND MAIN RESULTS

HBP was measured at nine different perioperative times. HBP levels increased immediately after heparin administration, further increased during CPB, but decreased rapidly after protamine administration. At arrival to the intensive care unit, median HBP levels were 24.8 (15.6-38.1) ng/mL for coronary artery bypass grafting patients and 51.2 (34.0-117.7) ng/mL for complex surgery patients (p = 0.011). One day after surgery, HBP levels in all three groups were below the proposed cutoff of 30 ng/mL, which previously was found to predict development of organ dysfunction in patients with infection.

CONCLUSIONS

HBP levels are elevated by the administration of heparin and the use of CPB but reduced by protamine administration. At postoperative day one, HBP levels were less than the threshold for organ dysfunction in patients with infection. The usefulness of HBP for predicting postoperative infections in cardiothoracic surgery should be investigated in future studies.

A post-preservation vascular flush removes significant populations of donor leukocytes prior to lung transplantation

BACKGROUND

Donor leukocytes are intrinsically involved in acute lung allograft rejection, via self-presentation of donor antigens to recipient leukocytes. Therapeutic modalities to remove donor leukocytes are currently unavailable. We evaluated if a vascular flush immediately following preservation can be used for this purpose.

METHODS

A post-preservation flush was performed with STEEN solution in n = 6 porcine lungs following static cold storage. The first 500 ml effluent from the left atrium was collected and an inflammatory profile performed.

RESULTS

A total of 1.17 billion (±2.8 × 10⁸) viable leukocytes were identified within the effluent. T cells were the dominant cell population, representing 82% of the total mobilised leukocytes, of which <0.01% were regulatory T cells. IL-18 was the most abundant cytokine, with a mean concentration of 84,216 pg (±153,552 pg). In addition, there was a mean concentration of 8819 ng (±4415) cell-free mitochondrial DNA.

CONCLUSION

There is an immediate transfer of donor leukocytes, cytokines and damage-associated molecular patterns following reperfusion. Such a pro-inflammatory donor load may enhance alloantigen presentation and drive recipient alloimmune responses. A post-preservation flush may therefore be an effective method for reducing the immune burden of the donor lung prior to transplantation.

Cardiopulmonary bypass duration is an independent predictor of adverse outcome in surgical repair for acute type A aortic dissection

OBJECTIVE

This study aimed to investigate the relationship between the duration of cardiopulmonary bypass (CPB) and stroke or early death in patients with acute type A aortic dissection (ATAAD) receiving total aortic arch replacement with the frozen elephant trunk procedure (TAR with FET).

METHODS

A retrospective cohort study of 258 consecutive patients was conducted at Beijing Anzhen Hospital from December 2014 to June 2016. Patients who received TAR with FET for ATAAD were included. An adverse outcome (AO) was defined as 30-day mortality or stroke. Additionally, an AO was compared using propensity score matching.

RESULTS

The incidence of AO was 13.6% (n = 35). The 30-day mortality rate was 10.8% and the stroke rate was 9.3%. Patients were aged 47.9 ± 10.6 years old. The duration of CPB was an independent predictor of occurrence of AO after adjusting for confounding factors by multivariable logistic regression analysis (odds ratio 1.101, 95% confidence interval 1.003-1.208). In matched analysis, CPB duration remained a risk factor of AO.

CONCLUSIONS

The duration of CPB is an independent predictor of AO in surgical repair for ATAAD. The underlying mechanisms of this association are important for developing improved prevention strategies.

Mitral valve surgery combined with on-pump versus off-pump myocardial revascularization: A prospective randomized analysis with midterm follow-up

BACKGROUND

The aim of the study was to compare results off-pump coronary artery bypass (OPCAB) combined mitral valve reconstruction (MVR) with standard on-pump approach.

METHODS

From January 2014 to December 2017, a total of 53 patients received a combined myocardial revascularization and MVR for multivessel coronary artery disease (CAD) complicated by severe ischemic mitral regurgitation (IMR). All the subjects were divided into two groups: group I: 27 patients, received OPCAB + MVR, and group II (control group): 26 patients with on-pump myocardial revascularization (ONCAB) + MVR.

RESULTS

The aortic cross-clamp (ACC) and cardio-pulmonary bypass (CPB) times were longer in group II, 47.0 (44.0; 55.0) vs 94.5 (89.75; 105.5) minutes, P < .05 and 70.0 (63.0; 77.0) vs 138.5 (127.0; 157.5) minutes, P < .05, respectively. Evaluation of major clinical events showed that the implementation of the off-pump stage of myocardial revascularization in patients with severe IMR did not lead to significant changes in the mortality and postoperative complications. Furthermore, its use did not affect the volume of blood loss and need for blood transfusion, the duration of mechanical ventilation, the need for inotropic therapy, as well as the duration of the patient's resuscitation and the total duration of hospitalization, with the one exception: the troponin-T level increase in the OPCAB + MVR group was less than in the ONCAB + MVR group.

CONCLUSION

OPCAB combined MVR in patients with CAD and severe IMR can be performed with shorter CPB and ACC times, and lower troponin-T level after surgery, without reducing the risk of surgical complications.

Model of Magnetic Particle Capture Under Physiological Flow Rates for Cytokine Removal During Cardiopulmonary Bypass

OBJECTIVE

The objective of this study is to design a physical model of a magnetic filtration system which can separate magnetic nanoparticle (MNP)-tagged cytokines from fluid at physiologically relevant flow rates employed during cardiopulmonary bypass (CPB) procedures.

METHODS

The Navier-Stokes equations for the pressure driven flow in the chamber and the quasistatic stray magnetic field produced by an array of permanent magnets were solved using finite element analysis in COMSOL Multiphysics for 2D and 3D representations of the flow chamber. Parameters affecting the drag and magnetic forces including flow chamber dimensions, high gradient magnet array configurations, and particle properties, were changed and evaluated for their effect on MNP capture.

RESULTS

Flow chamber dimensions which achieve appropriate flow conditions for CPB were identified, and magnetic force within the chamber decreased with increased chamber height. A magnetic "block" array produced the highest magnetic force within the chamber. Polymeric microparticles loaded with MNPs were shown to have increased particle capture with increased hydrodynamic diameter.

CONCLUSION

The model achieved a predicted efficiency up to 100% capture in a single-pass of fluid flowing at 1.75 L/min.

SIGNIFICANCE

This work is an important step in designing a magnetic flow chamber that can remove the magnetically tagged cytokines under high flow employed during CPB. Cytokines have been shown to stimulate the systemic inflammatory response (SIR) associated with CPB and are an established therapeutic target to mitigate the SIR. In the long term, this work aims to guide researchers in the more accurate design of magnetic separation systems.

Impact of minimal invasive extracorporeal circulation on atrial fibrillation after coronary artery bypass surgery

Postoperative atrial fibrillation (POAF) is the most common arrhythmia after cardiac surgery with an incidence between 15% and 50% and pathophysiology not fully known. By choosing the method of extracorporeal circulation with focus on the reduction of systemic inflammatory response, one can potentially decrease the risk of POAF. In this prospective, randomized trial, we compared minimal invasive extracorporeal circulation (MiECC) with conventional extracorporeal circulation (CECC) in the prevention of POAF after coronary artery bypass surgery (CABG). A total of 240 patients who were scheduled for their first on-pump CABG, were randomized to MiECC or CECC. The primary outcome measure was the incidence of first POAF during the first 84 hours after surgery. POAF occurred in 42/120 (35.0%) MiECC patients and 43/120 (35.8%) CECC patients with nonsignificant difference between the groups (OR 1.043, 95% CI 0.591-1.843, P = .884). The first postoperative creatine kinase-MB mass (CK-MBm) value was lower in the MiECC group, 13.95 [10.5-16.7] (median [IQR]) than in the CECC group, 15.30 [11.4-18.9] (P = .036), whereas the use of perioperative dobutamine was higher in the MiECC group, 18/120 (15.0%), than in the CECC group 8/120 (6.7%) (P = .038). The incidence of a stroke, perioperative myocardial infarction, and resternotomy caused by bleeding did not differ in the MiECC and CECC groups. Age (OR 1.08, 95% CI 1.04-1.13, P = .000) and peak postoperative CK-MBm (OR 1.57, 95% CI 1.06-2.37, P = .026) were independent predictors of POAF. MiECC compared to CECC was not effective in reducing the incidence of POAF in patients undergoing CABG.

Thoracoabdominal aneurysmectomy: Operative steps for Crawford extent II repair

Background

Open surgical repair remains the gold standard for treatment of thoracoabdominal aortic aneurysm (TAAA). Surgery aims to replace the whole length of the diseased distal aorta while protecting the spinal cord and the visceral organs to limit ischemia-related complications. The substantial associated surgical risks, including death, paraplegia, renal failure requiring permanent dialysis, and respiratory complications leading to prolonged intensive care unit stay, still outweigh the natural history of TAAA with conservative treatment.

Methods

We describe in detail our current approach to open extent II TAAA repair with a step-by-step illustration of the technique and the surgical adjuncts.

Results

We routinely perform left heart bypass with mild passive hypothermia (34°C), cerebrospinal fluid drainage, sequential aortic cross-clamping, monitoring of motor evoked potentials (MEPs) and cerebral, paraspinal, and lower limb oxygen saturation by near-infrared spectrometry, as well as selective visceral perfusion via the celiac and superior mesenteric arteries and renal protection with intermittent administration of Custodiol HTK (histidine-tryptophan-ketoglutarate) solution via the renal arteries. We advocate for individual branch reimplantation using a branched thoracoabdominal graft when possible, and we selectively reattach 1 or more pairs of the lower thoracic intercostal arteries and/or high lumbar arteries, even in the absence of a significant reduction in the MEPs signal. The distal anastomosis is usually constructed above the aortic bifurcation and occasionally to each iliac separately using a bifurcated graft.

Conclusions

Favorable early outcomes and a durable TAAA repair can be achieved at experienced high-volume centers with standardized preoperative selection and multidisciplinary team-based intraoperative and postoperative management of these patients.

Vasoplegic syndrome following cardiothoracic surgery-review of pathophysiology and update of treatment options

Vasoplegic syndrome is a common occurrence following cardiothoracic surgery and is characterized as a high-output shock state with poor systemic vascular resistance. The pathophysiology is complex and includes dysregulation of vasodilatory and vasoconstrictive properties of smooth vascular muscle cells. Specific bypass machine and patient factors play key roles in occurrence. Research into treatment of this syndrome is limited and extrapolated primarily from that pertaining to septic shock, but is evolving with the expanded use of catecholamine-sparing agents. Recent reports demonstrate potential benefit in novel treatment options, but large clinical trials are needed to confirm.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Accuracy of chest auscultation in detecting abnormal respiratory mechanics in the immediate postoperative period after cardiac surgery

Objective:

To investigate the accuracy of chest auscultation in detecting abnormal respiratory mechanics.

Methods:

We evaluated 200 mechanically ventilated patients in the immediate postoperative period after cardiac surgery. We assessed respiratory system mechanics - static compliance of the respiratory system (C_st,rs) and respiratory system resistance (R,rs) - after which two independent examiners, blinded to the respiratory system mechanics data, performed chest auscultation.

Results:

Neither decreased/abolished breath sounds nor crackles were associated with decreased C_st,rs (≤ 60 mL/cmH₂O), regardless of the examiner. The overall accuracy of chest auscultation was 34.0% and 42.0% for examiners A and B, respectively. The sensitivity and specificity of chest auscultation for detecting decreased/abolished breath sounds or crackles were 25.1% and 68.3%, respectively, for examiner A, versus 36.4% and 63.4%, respectively, for examiner B. Based on the judgments made by examiner A, there was a weak association between increased R,rs (≥ 15 cmH₂O/L/s) and rhonchi or wheezing (ϕ = 0.31, p < 0.01). The overall accuracy for detecting rhonchi or wheezing was 89.5% and 85.0% for examiners A and B, respectively. The sensitivity and specificity for detecting rhonchi or wheezing were 30.0% and 96.1%, respectively, for examiner A, versus 10.0% and 93.3%, respectively, for examiner B.

Conclusions:

Chest auscultation does not appear to be an accurate diagnostic method for detecting abnormal respiratory mechanics in mechanically ventilated patients in the immediate postoperative period after cardiac surgery.

Effect of goal-directed therapy on post-operative neutrophil gelatinase-associated lipocalin profile in patients undergoing on-pump coronary artery surgery

Purpose

Neutrophil gelatinase-associated lipocalin (NGAL) is an early biomarker of acute kidney injury (AKI). Goal-directed therapy (GDT) in on-pump coronary artery bypass grafting (CABG) has been associated with lower post-operative NGAL levels in recent studies. The present study aimed at comparing plasma (P) and urinary (U)-NGAL levels following the use of GDT versus conventional haemodynamic therapy (CT) in patients undergoing on-pump CABG.

Methods

A prospective randomised controlled study conducted in a single university hospital. A total of 54 patients in the GDT group and 56 patients in CT group after exclusions.

Results

U-NGAL was significantly lower immediately post-surgery (T ₁) in GDT group (25.11 ± 1.5 versus 27.80 ± 1.7 μg/L; p < 0.001) and at 4 h (T ₂) (38.19 ± 23.6 versus 52.30 ± 28.3 μg/L; p = 0.006) and at 24 h post-operatively (T ₃) (34.85 ± 14 versus 39.7 ± 11.1 μg/L; p = 0.047). P-NGAL was comparable between groups at T ₁ but lower in the GDT group at T ₂ (92.81 ± 4.8 versus 94.77 ± 4.5 μg/L; p = 0.03) and T ₃ (67.44 ± 3.7 versus 75.96 ± 5.3 μg/L; p < 0.001). U-NGAL levels correlated well with the peak post-operative creatinine as compared to P-NGAL. On-pump patients manifest neutrophil activation, accounting for comparable levels of P-NGAL in the two groups at T ₁. GDT-based haemodynamic management resulted in lower U-NGAL levels at T ₁, T ₂ and T ₃ and lower P-NGAL levels at T ₂ and T ₃.

Conclusions

Haemodynamic optimisation with GDT prevents further renal insult initiated with the inflammatory activation with cardiopulmonary bypass (CPB), as evidenced by lower post-operative U-NGAL levels.

Anesthetics to Prevent Lung Injury in Cardiac Surgery (APLICS): a protocol for a randomized controlled trial

Background

Patients undergoing cardiac surgery with cardiopulmonary bypass are at an increased risk of developing postoperative pulmonary complications, potentially leading to excess morbidity and mortality. It is likely that pulmonary ischemia-reperfusion (IR) injury during cardiopulmonary bypass is a major contributor to perioperative lung injury. Therefore, interventions that can minimize IR injury would be valuable in reducing the excess burden of this potentially preventable disease process. Volatile anesthetics including sevoflurane have been shown in both preclinical and human trials to effectively limit pulmonary inflammation in a number of settings including ischemia-reperfusion injury. However, this finding has not yet been demonstrated in the cardiac surgery population. The Anesthetics to Prevent Lung Injury in Cardiac Surgery (APLICS) trial is a randomized controlled trial (RCT) investigating whether sevoflurane anesthetic maintenance can modulate pulmonary inflammation occurring during cardiac surgery with cardiopulmonary bypass and whether this potential effect can translate to a reduction in postoperative pulmonary complications.

Methods

APLICS is a prospective RCT of adult cardiac surgical patients. Participants will be randomized to receive intraoperative anesthetic maintenance with either sevoflurane or propofol. Patients in both groups will be ventilated according to protocols intended to minimize the influences of ventilator-induced lung injury and hyperoxia. Bronchoalveolar lavage (BAL) and blood sampling will take place after anesthetic induction and 2–4 h after pulmonary reperfusion. The primary outcome is a difference between groups in the degree of post-bypass lung inflammation, defined by BAL concentrations of TNFα. Secondary outcomes will include differences in additional relevant BAL and systemic inflammatory markers and the incidence of postoperative pulmonary complications.

Discussion

APLICS investigates whether anesthetic choice can influence lung inflammation and pulmonary outcomes following cardiac surgery with cardiopulmonary bypass. A positive result from this trial would add to the growing body of evidence describing the lung protective properties of the volatile anesthetics and potentially reduce unnecessary morbidity for cardiac surgery patients.

Trial registration

ClinicalTrials.gov, NCT02918877. Registered on 29 September 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3400-x) contains supplementary material, which is available to authorized users.

Fluid Management With Peritoneal Dialysis After Pediatric Cardiac Surgery

Children who undergo cardiac surgery with cardiopulmonary bypass are a unique population at high risk for postoperative acute kidney injury (AKI) and fluid overload. Fluid management is important in the postoperative care of these children as fluid overload is associated with increased morbidity and mortality. Peritoneal dialysis catheters are an important tool in the armamentarium of a cardiac intensivist and are used for passive drainage for fluid removal or dialysis for electrolyte and uremia control in AKI. Prophylactic placement of a peritoneal catheter is a safe method of fluid removal that is associated with few major complications. Early initiation of peritoneal dialysis has been associated with improved clinical markers and outcomes such as early achievement of a negative fluid balance, lower vasoactive medication needs, shorter duration of mechanical ventilation, and decreased mortality. In this review, we discuss the safety and potential benefits of peritoneal catheters for dialysis or passive drainage in children following cardiopulmonary bypass.

Effects of methylprednisolone on blood-brain barrier and cerebral inflammation in cardiac surgery-a randomized trial

BACKGROUND

Cognitive dysfunction is a frequent complication to open-heart surgery. Cerebral inflammation caused by blood-brain barrier (BBB) dysfunction due to a systemic inflammatory response is considered a possible etiology. The effects of the glucocorticoid, methylprednisolone, on cerebrospinal fluid (CSF) markers of BBB function, neuroinflammation, and brain injury in patients undergoing cardiac surgery with cardiopulmonary bypass were studied.

METHODS

In this prospective, randomized, blinded study, 30 patients scheduled for elective surgical aortic valve replacement were randomized to methylprednisolone 15 mg/kg (n = 15) or placebo (n = 15) as a bolus dose administered after induction of anesthesia. CSF and blood samples were obtained the day before and 24 h after surgery for assessment of systemic and brain inflammation (interleukin-6, interleukin-8, tumor necrosis factor-alpha), axonal injury (total-tau, neurofilament light chain protein), neuronal injury (neuron-specific enolase), astroglial injury (S-100B, glial fibrillary acidic protein), and the BBB integrity (CSF/serum albumin ratio).

RESULTS

In the control group, there was a 54-fold and 17-fold increase in serum interleukin-6 and interleukin-8, respectively. This systemic activation of the inflammatory cytokines was clearly attenuated by methylprednisolone (p < 0.001). The increase of the CSF levels of the astroglial markers was not affected. A postoperative BBB dysfunction was seen in both groups as the CSF/serum albumin ratio increased from 6.4 ± 8.0 to 8.0 in the placebo group (p < 0.01) and from 5.6 ± 2.3 to 7.2 in the methylprednisolone group (p < 0.01) with no difference between groups (p = 0.98). In the CSF, methylprednisolone attenuated the interleukin-6 release (p < 0.001), which could be explained by the fall in systemic interleukin-6, and the serum to CSF gradient of IL-6 seen both at baseline and after surgery. In the CSF, methylprednisolone enhanced the interleukin-8 release (p < 0.001) but did not affect postoperative changes in CSF levels of tumor necrosis factor alpha. Serum levels of S-100B and neuron-specific enolase increased in both groups with no difference between groups. CSF levels of total tau, neurofilament light chain protein, and neuron-specific enolase were not affected in any of the groups.

CONCLUSIONS

Preventive treatment with high-dose methylprednisolone attenuated the systemic inflammatory response to open-heart surgery with cardiopulmonary bypass, but did not prevent or attenuate the increase in BBB permeability or the neuroinflammatory response.

TRIAL REGISTRATION

Clinical Trials, Identifier: NCT01755338 , registered 24 December 2012.

The Correlation between the Change in Thoracic Fluid Content and the Change in Patient Body Weight in Fontan Procedure

Background

The thoracic fluid content (TFC) and its percent change compared to the baseline (TFCd0%) derived from a bioreactance technique using a noninvasive cardiac output monitoring (NICOM) device correlate well with the amount of fluid removal in patients undergoing hemodialysis and with intraoperative fluid balance in pediatric patients undergoing cardiac surgery. We hypothesized that TFC or TFCd0% would also be a useful indicator allowing fluid management in pediatric patients undergoing a Fontan procedure.

Methods

The medical records of patients who underwent an elective Fontan procedure were reviewed retrospectively. The intraoperative variables recorded at two time points were used in the analysis: when the NICOM data obtained just after anesthesia induction (T0) and just before transfer of the patient from the operating room to the ICU (T1). The analyzed variables were hemodynamic parameters, TFC, TFCd0%, stroke volume variation, body weight gain, change in the central venous pressure, and difference in the TFC (ΔTFC).

Results

The correlation coefficient between TFCd0% and body weight gain was 0.546 (p = 0.01); between TFCd0% and body weight gain% 0.572 (p = 0.007); and between TFCd0% and intraoperative fluid balance 0.554 (p = 0.009). The coefficient of determination derived from a linear regression analysis of TFCd0% versus body weight gain was 0.30 (p = 0.01); between TFCd0% and body weight gain% 0.33 (p = 0.007); and between TFCd0% and intraoperative fluid balance 0.31 (p = 0.009).

Conclusions

TFCd0% correlated well with body weight gain, body weight gain%, and intraoperative fluid balance. It is a useful indicator in the intraoperative fluid management of pediatric patients undergoing a Fontan procedure.

Trial Registration

This trial is registered with Clinical Research Information Service KCT0002062.