Longer duration of cardiopulmonary bypass is associated with greater numbers of cerebral microemboli

Minimally invasive and robotic techniques for implantation of ventricular assist devices in patients with heart failure

INTRODUCTION

Minimally invasive approaches to cardiac surgery have been developing over the last several decades, including less invasive strategies to implantation of durable left ventricular assist devices (LVAD). Less invasive approaches to LVAD insertion aim to reduce surgical trauma and promote shorter hospital stay and recovery times; and for those bridged to heart transplantation, they aim to facilitate later reentry.

AREAS COVERED

PubMed was searched from 1980 to present to identify existing literature regarding non-sternotomy approaches to LVAD insertion. This review outlines the history and early attempts of sternal sparing LVAD insertion, commonly utilized surgical approaches in contemporary practice, as well as the experience with concomitant procedures using these approaches. Additionally, a summary of postoperative outcomes described in the literature is provided. Lastly, this review describes the early use of robotic assistance in durable LVAD implantation.

EXPERT OPINION

Sternal sparing approaches to LVAD insertion are feasible, safe, and in multiple experiences, have been shown to reduce operative and postoperative blood loss, reoperation, right ventricular dysfunction, and hospital length of stay. The use of surgical robotics in LVAD implantation remains at its infancy but poses a promising avenue to a totally endoscopic approach to durable mechanical assist therapy.

Moving from minimally invasive to totally endoscopic mitral valve surgery: a retrospective review of outcomes

OBJECTIVES

Mitral valve surgery has undergone significant advancements with the emergence of minimally invasive mitral surgery harnessing endoscopic technology to facilitate repair through a right anterior thoracotomy. Further refinement within the field has borne the novel totally endoscopic approach, reducing incision size, and surgical trauma, to 3 cm. While there is evidence to support non-inferiority of minimally invasive techniques compared to a traditional sternotomy, a knowledge gap exists regarding the comparative safety and efficacy between minimally invasive modalities, necessitating.

METHODS

A retrospective review of outcomes following totally endoscopic and minimally invasive mitral valve surgery by right anterior thoracotomy was completed. One hundred eighty-six patients were included, all operations having been performed by a single surgeon, between January 2019 and June 2023. The hypothesis posits that the former offers an equivalence in repair while reducing postoperative pain, bleeding from the wound and enhancing cosmesis.

RESULTS

While low 30-day mortality rates were seen in both cohorts, the totally endoscopic group exhibited lower rates of patients discharged with opiates (16% vs 23%), reduced blood product transfusion requirements (33% vs 43%) and shorter postoperative stays (mean of 9.2 days vs 11.4 days).

CONCLUSIONS

Moving from minimally invasive to totally endoscopic mitral valve surgery has been a positive experience with key patient advantages characterized by smaller incisions and avoidance of rib spreading. In this dataset, improved patient outcomes such as postoperative bleeding, pain, length of hospital stay and cosmesis were observed with all limitations given its fully uncontrolled nature. Validation of these findings warrants a larger study.

The Impact of Blood Pressure Below Personalized Lower Cerebral Autoregulation Limit on Outcomes After Cardiac Surgery: A Retrospective Study

OBJECTIVE

The clinical importance of individualized blood pressure management in optimizing cerebral perfusion during cardiac surgery has been well established. However, consensus on blood pressure goals is lacking. The authors studied the associations between cerebral autoregulation metrics, hemodynamic parameters, and postoperative outcomes, and hypothesized that increased time of mean arterial pressure (MAP) below the lower limit of autoregulation (LLA) is associated with major morbidity and mortality (MMOM) incidence.

DESIGN

A retrospective, observational study.

SETTING

A university hospital.

PARTICIPANTS

A total of 686 cardiovascular surgeries were included.

INTERVENTION

None.

MEASUREMENT AND MAIN RESULTS

The area under the time-pressure curve (AUC) for MAP < LLA and time below LLA (AUCABP48 hours, and postoperative mortality (ie, MMOM). There was no significant association between AUCABP 0.05). Relationships were observed between components of MMOM-operative mortality (p < 0.05) and low cardiac output syndrome (p < 0.05)-and AUCABP

CONCLUSIONS

These findings indicate that LLA-related metrics have limited utility for predicting MMOM. Future research should explore their applicability in various contexts and patient cohorts.

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Key Words

• cardiac surgery
• cerebral autoregulation
• cerebral oximetry index
• hemoglobin volume reactivity index
• low cardiac output syndrome
• lower limit of autoregulation
• operative mortality
• postoperative outcomes

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MESH Headings

• Humans
• Retrospective Studies
• Cardiac Surgical Procedures/adverse effects
• Cardiac Surgical Procedures/trends
• Male
• Female
• Homeostasis/physiology
• Aged
• Middle Aged
• Cerebrovascular Circulation/physiology
• Blood Pressure/physiology
• Postoperative Complications/physiopathology
• Postoperative Complications/epidemiology
• Treatment Outcome
• Precision Medicine/methods
• Precision Medicine/trends
• Arterial Pressure/physiology

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Affiliation(s)

Domagoj Mladinov Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
Ryan C Godwin Department of Anesthesiology and Perioperative Medicine, Department of Radiology, University of Alabama at Birmingham, Birmingham, AL
David Benz Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL
Ibukun Mary Folorunso Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL
Dan E Berkowitz Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL
Ryan L Melvin Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL.

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An intelligent DNA nanodevice for precision thrombolysis

Thrombosis is a leading global cause of death, in part due to the low efficacy of thrombolytic therapy. Here, we describe a method for precise delivery and accurate dosing of tissue plasminogen activator (tPA) using an intelligent DNA nanodevice. We use DNA origami to integrate DNA nanosheets with predesigned tPA binding sites and thrombin-responsive DNA fasteners. The fastener is an interlocking DNA triplex structure that acts as a thrombin recognizer, threshold controller and opening switch. When loaded with tPA and intravenously administrated in vivo, these DNA nanodevices rapidly target the site of thrombosis, track the circulating microemboli and expose the active tPA only when the concentration of thrombin exceeds a threshold. We demonstrate their improved therapeutic efficacy in ischaemic stroke and pulmonary embolism models, supporting the potential of these nanodevices to provide accurate tPA dosing for the treatment of different thromboses.

Tailored surgical strategies for mini-access open total arch repair

Objective

Open arch repair is perceived as a challenging, high-risk procedure, with a barrier against the use of a minimally invasive approach. We aimed to present a mini-access total arch replacement performed by stratified approaches and to evaluate perioperative outcomes to contribute to the body of evidence.

Methods

We evaluated 40 consecutive patients (aged 69.5 years; interquartile range, 65.6-76.3 years) undergoing elective total arch replacement using 5- to 8-cm upper mini-sternotomy between 2018 and 2022. Surgical strategies, including arterial inflow site and methods of branching vessel reconstruction, were systematically selected at the individual level. To evaluate comparative outcomes, contemporary cases undergoing total arch replacement via sternotomy with similar eligibility criteria served as a control group, and the inverse-treatment-weighting method was used to adjust for baseline characteristics.

Results

Arch-first anastomosis using trifurcate graft, distal-first anastomosis using 4-branch graft, and island anastomosis were used in 18 (45%), 12 (30.0%), and 10 (25%) patients, respectively. Lower body and cardiac ischemic times were 23.4 minutes (interquartile range, 18.0-29.0 minutes) and 66.7 minutes (interquartile range, 50.1-78.2 minutes). There was no early (30-day or in-hospital) mortality, and 2 patients experienced disabling stroke (5.0%). The contemporary control group comprised 55 patients. After an adjustment, a mini-access group showed lower risks of stroke (odds ratio, 0.88; 95% CI, 0.78-1.00; P = .049) and a composite of major complications (odds ratio, 0.79; 95% CI, 0.68-0.92; P = .003), compared with a sternotomy approach.

Conclusions

Based on present results, mini-access total arch replacement may be performed with reasonable safety and efficiency.

The Number of Microbubbles Generated During Cardiopulmonary Bypass Can Be Estimated Using Machine Learning From Suction Flow Rate, Venous Reservoir Level, Perfusion Flow Rate, Hematocrit Level, and Blood Temperature

GOAL

Microbubbles (MBs) are known to occur within the circuits of cardiopulmonary bypass (CPB) systems, and higher-order dysfunction after cardiac surgery may be caused by MBs as well as atheroma dispersal associated with cannula insertion. As complete MB elimination is not possible, monitoring MB count rates is critical. We propose an online detection system with a neural network-based model to estimate MB count rate using five parameters: suction flow rate, venous reservoir level, perfusion flow rate, hematocrit level, and blood temperature.

METHODS

Perfusion experiments were performed using an actual CPB circuit, and MB count rates were measured using the five varying parameters.

RESULTS

Bland-Altman analysis indicated a high estimation accuracy (R2 > 0.95, p < 0.001) with no significant systematic error. In clinical practice, although the inclusion of clinical procedures slightly decreased the estimation accuracy, a high coefficient of determination for 30 clinical cases (R2 = 0.8576) was achieved between measured and estimated MB count rates.

CONCLUSIONS

Our results highlight the potential of this system to improve patient outcomes and reduce MB-associated complication risk.

Risk Factors for Stroke Development After Thoracic Aortic Surgery

OBJECTIVES

Stroke after thoracic aortic surgery is a complication that is associated with poor outcomes. The aim is to characterize the intraoperative risk factors for stroke development.

DESIGN

A retrospective analysis.

SETTING

Tertiary, high-volume cardiac surgery center.

PARTICIPANTS

Patients who had surgical repair of thoracic aortic diseases from January 1, 2017, through December 31, 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 704 patients were included, of whom 533 had ascending aortic aneurysms, and 171 had type A aortic dissection. The incidence of postoperative stroke was 4.5% (95% CI 2.9%-6.6%) for ascending aortic aneurysms compared with 12.3% (95% CI 7.8%-18.16%) in type-A aortic dissections. Patients who developed postoperative strokes had significantly lower intraoperative hemoglobin median (7.5 gm/dL [IQR 6.8-8.6] v 8.55 gm/dL [IQR 7.3-10.0]; p < 0.001). The median cardiopulmonary bypass time was 185 minutes (IQR 136-328) in the stroke group versus 156 minutes (IQR 113-206) in the nonstroke group (p = 0.014). Circulatory arrest was used in 57.8% versus 38.5% of the nonstroke patients (p = 0.017). The initial temperature after leaving the operating room was lower, with a median of 35.0°C (IQR 34-35.92) in the stroke group versus 35.5°C (IQR 35-36) in the nonstroke cohort (p = 0.021).

CONCLUSIONS

This single-center study highlighted the potential importance of intra-operative factors in preventing stroke. Lower hemoglobin, longer duration of cardiopulmonary bypass, deep hypothermic circulatory arrest, and postoperative hypothermia are potential risk factors for postoperative stroke. Further studies are needed to prevent this significant complication in patients with thoracic aortic diseases.

Aortic arch redo surgery: early and mid-term outcomes in 120 patients

OBJECTIVES

The aim of this study was to analyse the indications, surgical extent and results of treatment, as well as determine the risk factors for adverse outcomes after redo arch surgery.

METHODS

Between January 1996 and December 2022, 120 patients underwent aortic arch reoperations after primary proximal aortic surgery. We retrospectively analysed perioperative data, as well as early and mid-term outcomes in these patients.

RESULTS

Indications for arch reintervention included new aortic aneurysm in 34 patients (28.3%), expanding post-dissection aneurysm in 36 (30.0%), aortic graft infection in 39 (32.5%) and new aortic dissection in 9 cases. Two patients underwent reoperation due to iatrogenic complications. Thirty-one patients (25.8%) had concomitant endocarditis. In-hospital and 30-day mortality rates were 11.7% and 15.0%, respectively. Stroke was observed in 11 (9.2%) and paraplegia in 1 patient. Prior surgery due to aneurysm [odds ratio 4.5; 95% confidence interval (CI) 1.4-17.3] and critical preoperative state (odds ratio 5.9; 95% CI 1.5-23.7) were independent predictors of 30-day mortality. Overall 1- and 5-year survival was 65.8 ± 8.8% and 51.2 ± 10.6%, respectively. Diabetes mellitus (hazard ratio 2.4; 95% CI 1.0-5.1) and peripheral arterial disease (hazard ratio 4.7; 95% CI 1.1-14.3) were independent predictors of late death. The cumulative incidence of reoperations was 12.6% (95% CI 6.7-20.4%) at 5 years. Accounting for mortality as a competing event, connective tissue disorders (subdistribution hazard ratio 4.5; 95% CI 1.6-15.7) and interval between primary and redo surgery (subdistribution hazard ratio 1.04; 95% CI 1.02-1.06) were independent predictors of reoperations after redo arch surgery.

CONCLUSIONS

Despite being technically demanding, aortic arch reoperations are feasible and can be performed with acceptable results.

Assessment of silent brain injury in patients undergoing elective percutaneous coronary intervention due to chronic total occlusion

Objective: Silent brain infarcts (SBI) are thromboembolic complications associated with cardiac surgery, diagnostic angiography, and percutaneous interventions. Serum neuron-specific enolase (NSE) is the proven biomarker for measuring neuronal damage. This study aimed to evaluate the incidence of SBI, defined as elevated NSE after coronary chronic total occlusion (CTO) intervention and elective coronary stenting. Design: The study population consisted of two patient groups: the CTO group included consecutive patients with coronary CTO intervention, and the control group consisted of patients who underwent elective coronary intervention. NSE blood levels were measured before and 12-18 h after the procedure. NSE blood levels of >20 ng/mL were considered SBI. Results: A total of 108 patients were included in the study. Of these, 55 (50.9%) had SBI after the procedure. The SBI rate was 59.7% in the CTO group and 39.1% in the control group. Patients with SBI were more likely to have diabetes mellitus, hyperlipidemia, higher HbA1c, higher total stent length, and longer procedural time. Multivariate logistic regression analysis showed that CTO procedure (odds ratio [OR]: 3.129; 95% confidence interval [CI]: 1.246-7.858; p < 0.015) and diabetes mellitus (OR: 2.93; 95% CI: 1.185-7.291; p < 0.020) are independent predictors of SBI. Conclusion: Our data suggest that SBI occurs more frequently after CTO intervention than after non-CTO intervention. Intervention complexity and patient clinical characteristics may explain the increased incidence.

Impact of Previous Conventional Cardiac Surgery on the Clinical Outcomes After Heart Transplantation

The impact of the type, purpose, and timing of prior surgery on heart transplantation (HT) remains unclear. This study investigated the influence of conventional cardiac surgery (PCCS) on HT outcomes. This study analyzed HTs performed between 1999 and 2019 at a single institution. Patients were categorized into two groups: those with and without PCCS. Short-term outcomes, including post-transplant complications and mortality rates, were evaluated. Cox proportional and Kaplan-Meier survival analyses were used to identify risk factors for mortality and assess long-term survival, respectively. Of 368 patients, 29% had PCCS. Patients with PCCS had a higher incidence of post-transplant complications. The in-hospital and 1 year mortality rates were higher in the PCCS group. PCCS and cardiopulmonary bypass time were significant risk factors for 1 year mortality (hazard ratios = 2.485 and 1.005, respectively). The long-term survival rates were lower in the PCCS group, particularly in the first year. In sub-analysis, patients with ischemic cardiomyopathy and PCCS had the poorest outcomes. The era of surgery and timing of PCCS in relation to HT did not significantly impact outcomes. In conclusion, PCCS worsen the HT outcomes, especially in patients with ischemic etiology. However, the timing of PCCS and era of HT did not significantly affect this concern.

Potentials of Acetylcholinesterase and Butyrylcholinesterase Alterations in On-Pump Coronary Artery Bypass Surgery in Postoperative Delirium: An Observational Trial

Cardiac surgery is regularly associated with postoperative delirium (POD), affected by neuro-inflammation and changes in cholinergic activity. Therefore, this prospective observational study aimed to evaluate whether pre- and perioperative changes in blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity were associated with POD development in patients undergoing isolated elective coronary artery bypass graft (CABG) surgery. It included 93 patients. Pre- and postoperative blood AChE and BChE activities were measured with photometric rapid-point-of-care-testing. The Intensive Care Delirium Screening Checklist and the Confusion Assessment Method for the Intensive Care Unit were used to screen patients for POD. POD developed in 20 patients (21.5%), who were older (p = 0.003), had higher EuroSCOREs (p ≤ 0.001), and had longer intensive care unit stays (p < 0.001). On postoperative day one, BChE activity decreased from preoperative values more in patients with (31.9%) than without (23.7%) POD (group difference p = 0.002). Applying a cutoff of ≥32.0% for BChE activity changes, receiver operating characteristic analysis demonstrated a moderate prediction capability for POD (area under the curve = 0.72, p = 0.002). The risk of developing POD was 4.31 times higher with a BChE activity change of ≥32.0% (p = 0.010). Monitoring the pre- to postoperative reduction in BChE activity might be a clinically practicable biomarker for detecting patients at risk of developing POD after CABG surgery.

Bilateral Axillary Artery Perfusion in Total Arch Replacement

BACKGROUND

The site of arterial cannulation is an important consideration in the prevention of cerebral infarction after total arch replacement. We compared the outcomes of cannulation of the bilateral axillary artery, the femoral artery, and central cannulation in total arch replacement.

METHODS

Enrolled were 242 patients, categorized into three groups according to the arterial cannulation site used: bilateral axillary artery group, 124 patients; femoral artery group, 88 patients; central cannulation group, 30 patients. Selective cerebral perfusion was used for brain protection in all patients. Surgical outcomes, including the incidence of postoperative cerebral infarction, were compared between the groups.

RESULTS

Cardiopulmonary bypass time and lower-body circulatory arrest time were significantly shorter in the bilateral axillary artery group. Frozen elephant trunk procedure was performed in 54% of the bilateral axillary artery group (P < .001), and concomitant coronary artery bypass graft surgery was performed in 40% of the central cannulation group (P < .01). Hospital mortality in the bilateral axillary artery group was 1.6%, compared with 1.1% in the femoral artery group, and 0% in the central cannulation group (P = .72). The incidence of permanent neurologic deficit was significantly lower in the bilateral axillary artery group (0.8%) than in the central cannulation group (13%; P = .02). Logistic regression analysis indicated that bilateral axillary artery perfusion was a significant factor in the prevention of permanent neurologic deficit (odds ratio 0.10, P = .03).

CONCLUSIONS

Recent technical advances using bilateral axillary artery perfusion and frozen elephant trunk technique were associated with shortening cardiopulmonary bypass time and prevention of postoperative cerebral infarction in total arch replacement.

Differences among sexes in presentation and outcomes in acute type A aortic dissection repair

OBJECTIVE

Female sex is a known risk factor in most cardiac surgery, including coronary and valve surgery, but unknown in acute type A aortic dissection repair.

METHODS

From 1996 to 2018, 650 patients underwent acute type A aortic dissection repair; 206 (32%) were female, and 444 (68%) were male. Data were collected through the Cardiac Surgery Data Warehouse, medical record review, and National Death Index database.

RESULTS

Compared with men, women were significantly older (65 vs 57 years, P < .0001). The proportion of women and men inverted with increasing age, with 23% of patients aged less than 50 years and 65% of patients aged 80 years or older being female. Women had significantly less chronic renal failure (2.0% vs 5.4%, P = .04), acute myocardial infarction (1.0% vs 3.8%, P = .04), and severe aortic insufficiency. Women underwent significantly fewer aortic root replacements with similar aortic arch procedures, shorter cardiopulmonary bypass times (211 vs 229 minutes, P = .0001), and aortic crossclamp times (132 vs 164 minutes, P < .0001), but required more intraoperative blood transfusion (4 vs 3 units) compared with men. Women had significantly lower operative mortality (4.9% vs 9.5%, P = .04), especially in those aged more than 70 years (4.4% vs 16%, P = .02). The significant risk factors for operative mortality were male sex (odds ratio, 2.2), chronic renal failure (odds ratio, 3.4), and cardiogenic shock (odds ratio, 6.8). The 10-year survival was similar between sexes.

CONCLUSIONS

Physicians and women should be cognizant of the risk of acute type A aortic dissection later in life in women. Surgeons should strongly consider operations for acute type A aortic dissection in women, especially in patients aged 70 years or more.

Continuous electroencephalography (cEEG) in infants with congenital heart disease (CHD)

BACKGROUND

Neonates with congenital heart disease (CHD) undergoing cardiopulmonary bypass (CPB) surgery have increased risk of impaired neurodevelopmental outcomes secondary to brain injury. This study aims to characterize pre- and post-operative continuous EEG (cEEG) patterns to detect abnormal cerebral activity in infants with CHD and investigate whether an association exists between the degree of encephalopathy in pre- and post-operative cEEG.

METHODS

This retrospective cohort study conducted between 2010 and 2018 at a tertiary hospital in Cleveland, OH included infants with CHD with cEEG monitoring, who underwent CPB surgery within first 6 months of life.

RESULTS

Study included 77 patients, of which 61% were males who were operated at median age 6 days. Pre-operatively, 69% and 87% had normal cEEG and sleep-wake cycles, respectively. Post-operatively, 80% had abnormal cEEG. Longer circulatory arrest time and CPB were associated with lack of continuity (p 0.011), excessive discontinuity (p 0.007) and prolonged inter-burst interval (IBI) duration (p value < 0.001). A significant association existed between severity of encephalopathy in immediate and 24-h post-operative period (p value < 0.001).

CONCLUSIONS

More than 80% of neonates with CHD have abnormal post-operative EEG. Longer circulatory arrest time and CPB were associated with lack of continuity, excessive discontinuity, and prolonged IBI duration on post-operative EEG.

IMPACT

This study shows that majority of neonates with congenital heart disease (CHD) have normal pre-operative EEG with a continuous background and normal sleep-wake cycles. Also, 80% of neonates had abnormal post-operative EEG. Longer duration of arrest time and bypass time was associated with lack of continuity, excessive discontinuity, and prolonged IBI duration during post-operative EEG monitoring. These findings will help clinicians when counseling parents in the intensive care unit, risk stratification, and long-term neurodevelopmental monitoring in these high-risk patients.

Microvascular dysfunction following cardiopulmonary bypass plays a central role in postoperative organ dysfunction

Despite significant advances in surgical technique and strategies for tissue/organ protection, cardiac surgery involving cardiopulmonary bypass is a profound stressor on the human body and is associated with numerous intraoperative and postoperative collateral effects across different tissues and organ systems. Of note, cardiopulmonary bypass has been shown to induce significant alterations in microvascular reactivity. This involves altered myogenic tone, altered microvascular responsiveness to many endogenous vasoactive agonists, and generalized endothelial dysfunction across multiple vascular beds. This review begins with a survey of in vitro studies that examine the cellular mechanisms of microvascular dysfunction following cardiac surgery involving cardiopulmonary bypass, with a focus on endothelial activation, weakened barrier integrity, altered cell surface receptor expression, and changes in the balance between vasoconstrictive and vasodilatory mediators. Microvascular dysfunction in turn influences postoperative organ dysfunction in complex, poorly understood ways. Hence the second part of this review will highlight in vivo studies examining the effects of cardiac surgery on critical organ systems, notably the heart, brain, renal system, and skin/peripheral tissue vasculature. Clinical implications and possible areas for intervention will be discussed throughout the review.

Visual Hallucinations following Coronary Artery Bypass Grafting: A Prospective Study

Background and Objectives: After major heart surgery, some patients report visual hallucinations that cannot be attributed to psychosis or delirium. This study aimed to investigate the hallucination incidence in patients after coronary artery bypass grafting with (on-pump) and without (off-pump) extracorporeal circulation. Materials and Methods: A total of 184 consecutive patients listed for elective on- or off-pump coronary artery bypass grafting were prospectively enrolled into the study. Preoperative baseline investigations 24–48 h before surgery (t0) and postoperative follow-up 24–48 h (t1) and 5–6 days (t2) after surgery included cognitive testing and a clinical visual acuity test (Landolt rings). Patients reporting visual hallucinations were interviewed using a structured survey to record the type, timing, duration, and frequency of their hallucinations. All the patients received a neurological examination and cranial magnetic resonance imaging if indicated. Results: Of the patients in the sample, 155 patients underwent on-pump bypass surgery, and 29 patients received off-pump surgery. Of these, 25 patients in the on-pump group, but none in the off-pump group, reported transient visual hallucinations (p = 0.020), which could not be attributed to stroke, delirium, psychosis, migraine, or severely impaired vision. Significant correlations were observed for the occurrence of visual hallucinations and the amount of nicotine consumption and aortic clamp/extracorporeal circulation time. Conclusions: Transient visual hallucinations occur in a noticeable proportion of patients after on-pump heart surgery. Knowledge of the phenomenon’s benignity is important for patients to prevent anxiety and uncertainty and for treating physicians to avoid unnecessary medication and drug-induced delirium.

Neural Network-based Estimation of Microbubbles Generated in Cardiopulmonary Bypass Circuit: A Clinical Application Study

The cardiopulmonary bypass system used in cardiac surgery can generate microbubbles (MBs) that may cause complications, such as neurocognitive dysfunction, when delivered into the blood vessel. Estimating the number of MBs generated, thus, is necessary to enable the surgeons to deal with it. To this end, we previously proposed a neural network-based model for estimating the number of MBs from four factors measurable from the cardiopulmonary bypass system: suction flow rate, venous reservoir level, blood viscosity, and perfusion flow rate. However, the model has not been adapted to the data collected from actual surgery cases. In this study, the accuracy of MBs estimated by the proposed model was examined in four clinical cases. The results showed that the coefficient of determination between estimated MBs and the measured MBs throughout the surgeries was R2=0.558 (p<0.001). We found that the surgical treatments, such as administration of drugs, fluids and blood transfusions, increased the number of measured MBs. The coefficient of determination increased to R²= 0.8762 (p<0.001) by excluding the duration of these treatments. This result indicates that the model can estimate the number of MBs with high accuracy under the clinical environment.

Intraoperative Glycemic Variability and Mean Glucose are Predictors for Postoperative Delirium After Cardiac Surgery: A Retrospective Cohort Study

Purpose

Postoperative delirium (POD) is a common but serious complication after cardiac surgery and is associated with various short- and long-term outcomes. In this study, we investigated the effects of intraoperative glycemic variability (GV) and other glycemic variables on POD after cardiac surgery.

Patients and Methods

A retrospective single-center cohort analysis was conducted using data from electronic medical record from 2018 to 2020. A total of 705 patients undergoing coronary artery bypass graft surgery and/or valve surgery, and/or aortic replacement surgery were included in the analysis. Intraoperative GV was assessed with a coefficient of variation (CV), which was defined as the standard deviation of five intraoperative blood glucose measurements divided by the mean. POD assessment was performed three times a day in the ICU and twice a day in the ward until discharge by trained medical staff. POD was diagnosed if any of the Confusion Assessment Method for the Intensive Care Unit was positive in the ICU, and the Confusion Assessment Method was positive in the ward. Multivariable logistic regression was used to identify associations between intraoperative GV and POD.

Results

POD occurred in 306 (43.4%) patients. When intraoperative glycemic CV was compared as a continuous variable, the delirium group had higher intraoperative glycemic CV than the non-delirium group (22.59 [17.09, 29.68] vs 18.19 [13.00, 23.35], p < 0.001), and when intraoperative glycemic CV was classified as quartiles, the incidence of POD increased as intraoperative glycemic CV quartiles increased (first quartile 29.89%; second quartile 36.67%; third quartile 44.63%; and fourth quartile 62.64%, p < 0.001). In the multivariable logistic regression model, patients in the third quartile of intraoperative glycemic CV were 1.833 times (OR 1.833, 95% CI: 1.132–2.967, p = 0.014), and patients in the fourth quartile of intraoperative glycemic CV were 3.645 times (OR 3.645, 95% CI: 2.235–5.944, p < 0.001) more likely to develop POD than those in the first quartile of intraoperative glycemic CV.

Conclusion

Intraoperative blood glucose fluctuation, manifested by intraoperative GV, is associated with POD after cardiac surgery. Patients with a higher intraoperative GV have an increased risk of POD.

Cerebral Large Vessel Occlusion Caused by Fat Embolism-A Case Series and Review of the Literature

The diagnosis of fat embolism syndrome typically involves neurological, respiratory and dermatological manifestations of microvascular occlusion 24–72 h after a precipitating event. However, fat embolism causing cerebral large vessel occlusion strokes and their sequelae have rarely been reported in the literature. This case series reports three patients with fat emboli post operatively causing cerebral large vessel occlusions, as well as a review of the literature to identify differences in clinical presentations and outcomes in stroke secondary to fat emboli causing large vessel occlusions compared to those with fat embolism syndrome.

Influence of cardiopulmonary bypass set-up and management on clinical outcomes after minimally invasive aortic valve surgery

INTRODUCTION

Minimally invasive aortic valve replacement (MIAVR) requires changes in cannulation strategy and cardiopulmonary bypass (CPB) management when compared to the conventional approach (CAVR). We aimed at evaluating if these differences could influence perfusion-related quality parameters and impair postoperative outcomes.

METHODS

Overall, 339 consecutive patients underwent MIAVR or CAVR between 2014 and 2020 and were analyzed retrospectively. To account for baseline differences, a propensity-matching analysis was performed, obtaining two groups of 97 patients each.

RESULTS

MIAVR group had longer CPB time [107 (95-120) vs 95 (86-105) min, p = .003] than CAVR group. Of note, average pump flow rate index [2.4 (2.2-2.5) vs 2.7 (2.4-2.8) l/min/m², p = .004] was lower in the MIAVR group. Mean arterial pressure was 73 = 9 mmHg vs 62 = 11 mmHg for the MIAVR and CAVR group, respectively (p < .001). Cell-salvaged blood was most commonly used in the MIAVR group (25.8% vs 11.3%, p = .02). Finally, CPB temperature was 32.8°C (32.1-34.8) for MIAVR group vs 34.9°C (33.2-36.1) for the CAVR group (p = .02). Postoperative complications were similar between groups.

CONCLUSIONS

In conclusion, despite differences in CPB parameters in patients undergoing CAVR and MIAVR, the incidences of adverse outcomes were similar. However, compared to CAVR, MIAVR was associated with shorter durations of mechanical ventilation and hospital stay as well as less transfusion of blood products.

Cerebral microemboli in mini-sternotomy compared to mini- thoracotomy for aortic valve replacement: a cross sectional cohort study

Background

Recently adopted mini-thoracotomy approach for surgical aortic valve replacement has shown benefits such as reduced pain and shorter recovery, compared to more conventional mini-sternotomy access. However, whether limited exposure of the heart and ascending aorta resulting from an incision in the second intercostal space may lead to increased intraoperative cerebral embolization and more prominent postoperative neurologic decline, remains inconclusive. The aim of our study was to assess potential neurological complications after two different minimal invasive surgical techniques for aortic valve replacement by measuring cerebral microembolic signal during surgery and by follow-up cognitive evaluation.

Methods

Trans-cranial Doppler was used for microembolic signal detection during aortic valve replacement performed via mini-sternotomy and mini-thoracotomy. Patients were evaluated using Addenbrooke’s Cognitive Examination Revised Test before and 30 days after surgical procedure.

Results

A total of 60 patients were recruited in the study. In 52 patients, transcranial Doppler was feasible. Of those, 25 underwent mini-sternotomy and 27 had mini-thoracotomy. There were no differences between groups with respect to sex, NYHA class distribution, Euroscore II or aortic valve area. Patients in mini-sternotomy group were younger (60.8 ± 14.4 vs.72 ± 5.84, p = 0.003), heavier (85.2 ± 12.4 vs.72.5 ± 12.9, p = 0.002) and had higher body surface area (1.98 ± 0.167 vs. 1.83 ± 0.178, p = 0.006). Surgery duration was longer in mini-sternotomy group compared to mini-thoracotomy (158 ± 24 vs. 134 ± 30 min, p < 0.001, respectively). There were no differences between groups in microembolic load, length of ICU or total hospital stay. Total microembolic signals count was correlated with cardiopulmonary bypass duration (5.64, 95%CI 0.677–10.60, p = 0.027). Addenbrooke’s Cognitive Examination Revised Test score decreased equivalently in both groups (p = 0.630) (MS: 85.2 ± 9.6 vs. 82.9 ± 11.4, p = 0.012; MT: 85.2 ± 9.6 vs. 81.3 ± 8.8, p = 0.001).

Conclusion

There is no difference in microembolic load between the groups. Total intraoperative microembolic signals count was associated with cardiopulmonary bypass duration. Age, but not micorembolic signals load, was associated with postoperative neurologic decline.

Trial registry number

clinicaltrials.gov, NCT02697786 14.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01509-8.

Fate of moderate aortic regurgitation after cardiac surgery

OBJECTIVE

To determine the prevalence of concomitant aortic regurgitation (AR) in cardiac surgery and the outcomes of treatment options.

METHODS

Between April 2004 and June 2018, 3289 patients underwent coronary artery bypass, mitral valve, or aortic aneurysm surgery without aortic stenosis. AR was graded none/trivial (score = 0), mild (score = 1+), or moderate (score = 2+). Patients with untreated 2+ AR were compared with those with 0 or 1+ AR, and to those with 2+ AR who had aortic valve surgery. Thirty-day and late survival, echocardiography, and clinical outcomes were compared using propensity score matching.

RESULTS

One hundred thirty-eight patients (4.2%) had 2+ AR; and 45 (33%) received aortic valve repair (n = 9) or replacement (n = 36) in the treated group and were compared with 2765 untreated patients with 0 AR and 386 patients with 1+ AR. Valve surgery was more common with anatomic leaflet abnormalities: bicuspid aortic valve (9% vs 0%; P < .01), rheumatic valve disease (16% vs 3%; P < .01), and calcification (47% vs 27%; P = .021). In unadjusted analysis, lower preoperative AR grade was associated with increased 10-year survival (P < .001). At year 10, progression to more-than-moderate AR among moderate AR patients was 2.6% and late intervention rate was 3.1%. In the untreated 2+ AR group, on last follow-up echocardiogram, 58% had improvement in AR, 41% remained 2+, and only 1% progressed to severe AR.

CONCLUSIONS

Aortic valve surgery in select patients with concomitant moderate AR can be added with minimal added risk, but untreated AR does not influence long-term survival after cardiac surgery and rarely required late intervention.

[Current problems of simultaneous surgery of the aortic valve and ischaemic heart disease]

Surgical policy in treatment of patients suffering from concomitant valvular pathology and ischaemic heart disease is an extremely important problem of contemporary cardiac surgery. With the advent of advanced techniques and due to the improvement of old ones, there have over the last decades appeared new approaches to treatment of this cohort of patients. Presented in the article is a review of current publications regarding the problem of surgical treatment of patients with a combination of pronounced valvular pathology requiring surgical correction and ischaemic heart disease necessitating the need for myocardial revascularization. This is followed by providing the data concerning contemporary strategies of treatment of patients with concomitant pathology, as well as the comparison of various approaches and the effect of the chosen technique on the outcome.

Aortic valve replacement using stented or sutureless/rapid deployment prosthesis via either full-sternotomy or a minimally invasive approach: a network meta-analysis

Background

New technologies such as sutureless or rapid deployment prosthetic valves and access via minimally invasive incisions offer alternatives to traditional full-sternotomy aortic valve replacement (SAVR). However, a comprehensive comparison of these surgical techniques along with alternative valve prosthesis has not been completed.

Methods

Electronic databases were searched for studies comparing outcomes for SAVR, minimally invasive AVR (MiAVR), sutureless/rapid-deployment AVR (SuAVR) via full-sternotomy, or minimally invasive SuAVR (MiSuAVR) from their inception until September 2018. Early postoperative outcomes and follow-up data were included in a Bayesian network meta-analysis.

Results

Twenty-three studies with 8,718 patients were identified. Compared with standard SAVR, SuAVR had significantly lower incidence of postoperative AF [odds ratio (OR) 0.33, 95% confidence interval (CI): 0.14-0.79, P=0.013] and MiSuAVR greater requirement for postoperative permanent pacemaker (OR 2.27, 95% CI: 1.25-4.14, P=0.008). All sutureless/rapid-deployment procedures had reduced cardiopulmonary bypass and cross-clamp times, by a mean of 25.9 and 25.0 min, respectively. Hospital length of stay (LOS), but not intensive care LOS, was reduced for all groups (MiAVR -1.53 days, MiSuAVR -2.79 days, and SuAVR 3.37 days). A signal towards reduced early mortality, wound infections, and acute kidney injury was noted in both sutureless/rapid-deployment and minimally invasive techniques but did not achieve significance. Sutureless/rapid-deployment procedures had favourable survival and freedom from valve related reoperation, however follow-up times were short and demonstrated significant heterogeneity between intervention groups.

Conclusions

Minimally invasive and sutureless techniques demonstrate equivalent early postoperative outcomes to SAVR and may reduce ventilation time, hospital LOS and postoperative atrial fibrillation (POAF) burden.

Establishment and Evaluation of a Monkey Acute Cerebral Ischemia Model

OBJECTIVES

Cerebral ischemia seriously threatens human health and is characterized by high rates of incidence, disability and death. Developing an ideal animal model of cerebral ischemia that reflects the human clinical features is critical for pathological studies and clinical research. The goal of this study is to establish a local cerebral ischemia model in rhesus macaque, thereby providing an optimal animal model to study cerebral ischemia.

METHODS

Eight healthy rhesus monkeys were selected for this study. CT scans were performed before the operation to exclude cerebral vascular and intracranial lesions. Under guidance and monitoring with digital subtraction angiography (DSA), a microcatheter was inserted into the M1 segment of the middle cerebral artery (MCA) via the femoral artery. Then, autologous white thrombi were introduced to block blood flow. Immediately following embolization, multisequence MRI was used to monitor cerebrovascular and brain parenchymal conditions. Twenty-four hours after embolization, 2 monkeys were sacrificed and subjected to perfusion, fixation and pathological examination.

RESULTS

The cerebral ischemia model was established in 7 rhesus monkeys; one animal died during intubation. DSA and magnetic resonance angiography (MRA) indicated the presence of an arterial occlusion. MRI showed acute local cerebral ischemia. HE staining revealed infarct lesions formed in the brain tissues, and thrombi were present in the cerebral artery.

CONCLUSION

We established a rhesus macaque model of local cerebral ischemia by autologous thrombus placement. This model has important implications for basic and clinical research on cerebral ischemia. MRI and DSA can evaluate the models to ensure accuracy and effectiveness.

Neuroprotective Effect of Low Mean Arterial Pressure on Postoperative Cognitive Deficit Attenuated by Prolonged Coronary Artery Bypass Time: A Meta-Analysis

Introduction

The true influence of the low mean arterial pressure (low MAP) during coronary artery bypass grafting (CABG) on the development of postoperative cognitive deficit (POCD) remains controversial. We aimed to perform a meta-analysis and meta-regression to determine the effect of low MAP on POCD, as well as moderator variables between low MAP and POCD.

Methods

The Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2018) were searched and retrieved articles systematically reviewed. Only randomized controlled trials (RCTs) comparing maintenance of low MAP (<80 mmHg) and high MAP (>80 mmHg) during cardiopulmonary bypass (CPB) were included in our final review. Statistical analysis of the risk ratio (RR) and corresponding 95% confidence interval (CI) was used to report the overall effect. The overall effect and meta-regression analysis were done using Mantel-Haenszel risk ratio (MHRR) and the corresponding 95% confidence interval (CI).

Results

A total of 731 patients in three RCTs were included in this study. POCD occurred in 6.4% of all cases. Maintenance of low MAP did not reduce the occurrence of POCD (MHRR 1.012 [95% CI 0.277-3.688]; Z=0.018; P=0.986; I²=66%). Shorter CPB time reduced the occurrence of POCD regardless of group assignment (MH log risk ratio -0.519 [95% CI -0.949 - -0.089]; Z= -2.367; P=0.017).

Conclusion

POCD is a common event among CABG patients. The neuroprotective effect of low MAP on POCD was attenuated by the prolonged CPB time.

Intensive Care Unit Readmission After Left Ventricular Assist Device Implantation: Causes, Associated Factors, and Association With Patient Mortality

BACKGROUND

Previous studies on readmissions after left ventricular assist device (LVAD) implantation have focused on hospital readmissions after dismissal from the index hospitalization. Because few data exist, the purpose of this study was to examine intensive care unit (ICU) readmissions in patients during their initial hospitalization for LVAD implantation to determine reasons for, factors associated with, and incidence of mortality after ICU readmission.

METHODS

A retrospective analysis was performed from February 2007 to March 2015 of patients at our institution receiving first-time LVAD implantation. After LVAD implantation, patients dismissed from the ICU who then required ICU readmission before hospital dismissal were compared to those not requiring ICU readmission before hospital dismissal with respect to preoperative, intraoperative, and postoperative factors.

RESULTS

Among 287 LVAD patients, 266 survived their initial ICU admission, of which 49 (18.4%) required ICU readmission. The most common reasons for readmission were bleeding and respiratory failure. Factors found to be univariably associated with ICU readmission were preoperative hemoglobin, preoperative aspartate aminotransferase, preoperative atrial fibrillation, preoperative dialysis, longer cardiopulmonary bypass times, and higher intraoperative allogeneic blood transfusion requirements. Multivariable analysis revealed ICU readmission to be independently associated with preoperative dialysis (odds ratio, 12.86; 95% confidence interval, 3.16-52.28; P < .001). Overall mortality at 1 year was 22.6%. Survival after hospital dismissal was worse for patients who required ICU readmission during the index hospitalization (adjusted hazard ratio, 2.35; 95% confidence interval, 1.15-4.81; P = .019).

CONCLUSIONS

ICU readmission after LVAD implantation occurred relatively frequently and was significantly associated with 1-year mortality after hospital dismissal. These data can perhaps be used to identify subsets of LVAD patients at risk for ICU readmission and may lead to implementation of practice changes to mitigate ICU readmissions. Future larger and prospective studies are warranted.

Intermittent on-pump beating-heart coronary artery bypass grafting-a safer option

Purpose

On-pump beating-heart coronary artery bypass grafting represents a merger of standard on and off-pump techniques and is thought to benefit patients by coupling the dual absence of cardioplegic arrest (conventional coronary surgery), with the hemodynamic instability during manipulation seen in off-pump surgery. However, the clinical benefits are still under discussion. We improvised on the standard on-pump beating-heart surgeries by introducing use of "intermittent" bypass as and when required.

Methods

This study involved 108 patients. "Intermittent" on-pump-beating heart coronary artery bypass grafting was done using suction stabilizer and placing aortic and venous cannula, electively in all patients (group 1) who were supported by pump intermittently (n = 54). Retrospective data of patients who underwent off-pump surgery electively by the same surgeon (group 2, n = 54) was collected.

Results

There was a significant advantage in the number of grafts performed for the lateral surface (circumflex branches) using the new technique compared to conventional technique (68vs22). Similarly, significant advantage was also noted in terms of total number of grafts along with shorter operating times. There were no mortalities in the new group compared to the off-pump group and blood loss was also lesser.

Conclusions

"Intermittent" on-pump coronary revascularization is a technically reliable method of coronary revascularization taking advantage of the off-pump and conventional on-pump techniques while considerably eliminating the disadvantages of both. It has shown its superiority in safety, number of grafts, blood loss, operating time and perioperative course.

Cardiopulmonary Bypass Alone Does Not Cause Postoperative Cognitive Dysfunction Following Open Heart Surgery

Background

Postoperative cognitive dysfunction (POCD) is commonly observed following cardiac surgery. The utilization of cardiopulmonary bypass (CPB) is associated with many possible mechanisms to cause POCD. However, there is no evidence confirming that CPB alone is the cause of POCD.

Objectives

The current study aimed at evaluating several factors suspected to cause POCD following cardiac surgery in Cipto Mangunkusumo Hospital, Jakarta, Indonesia.

Methods

The current prospective cohort study was conducted on 54 patients who were candidates for cardiac surgery. The assessment of memory, attention, and executive functions was performed by neuropsychological tests, before and after the surgery. Cognitive decline was defined as a 20% decrease in cognitive function in at least one of the tests. Inclusion criteria were adults spokeing Bahasa Indonesia fluently, literate, and giving consent to participate in the study. The analyzed risk factors included age, diabetes, educational level, duration of aortic cross clamp, and duration of cardio-pulmonary bypass.

Results

POCD occured in 40.7% of subjects that underwent cardiac surgery using cardiopulmonary bypass. Age was the only influential factor through bivariate test and logistic regression analysis (P = 0.001). The current study conducted a logistic regression test on age variable; the obtained result indicated an increasing trend of POCD in accordance with age group.

Conclusions

Durations of CPB, cross clamp, diabetes, and educational level were not the main risks of POCD. Old age was a significant predictor to POCD.

Comparison of Frequency of Silent Cerebral Infarction After Coronary Angiography and Stenting With Transradial Versus Transfemoral Approaches

Silent cerebral infarction (SCI) can be seen after coronary procedures. We investigated whether vascular access sites have an impact on the risk of SCI. A total of 255 consecutive patients who underwent diagnostic or interventional coronary procedures through transfemoral (n = 126 patients) or transradial (n = 129 patients) approach were evaluated. Neuron-specific enolase (NSE) levels were studied before and 12 hours after the procedure. Elevation of greater than 12 ng/ml was considered as SCI. Patients were mainly men (60%) with a mean age of 62 years. SCI was observed in 74 of 255 patients (29%). It was significantly more prevalent among transradial group. Elevation of NSE was observed in 36% of transradial group (n = 47) and 21% of the transfemoral group (n = 27) (p = 0.008). Patients with SCI were more likely to have male sexuality, hyperlipidemia, history of smoking, and previous myocardial infarction. Multivariate analysis demonstrated that patients who underwent coronary procedures through transradial approach were 2.1 times more likely to have an SCI than patients with transfemoral approach (95% confidence interval [CI] 1.205 to 3.666; p = 0.008). Other independent predictors of NSE elevation were previous myocardial infarction (odds ratio 8.6; 95% CI 4.209 to 17.572; p <0.001) and smoking history (odds ratio 7.251; 95% CI 3.855 to 13.639; p <0.001). The present study suggests that transradial coronary procedures carry higher risk of SCI when compared with transfemoral route.

On-pump beating heart versus conventional coronary artery bypass grafting: comparative study on early and long-term clinical outcomes

Background

We reviewed our experience with on-pump beating (OPB) heart coronary artery bypass grafting (CABG) to evaluate the impacts of obviating aortic cross-clamping and cardioplegic arrest on clinical outcomes compared with conventional CABG (C-CABG).

Methods

Between 2006 and 2012, elective isolated cardiopulmonary bypass (CPB)-assisted CABG was consecutively performed in 645 patients (mean patient age 63.3±9.1 years, 471 women) with 254 (39.4%) undergoing OPB-CABG and 391 (60.6%) undergoing C-CABG. The early and long-term clinical outcomes were compared between the two groups after adjusting for risk profiles through propensity score (PS) analyses.

Results

The OPB-CABG group presented significant morbidities more frequently than the C-CABG group, including severe chronic kidney disease (CKD) (P=0.026), severe chest pain (P<0.001), and poor left ventricular function (P<0.001). Early mortality occurred in 6 (2.4%) and 2 (0.5%) patients in the OPB- and C-CABG group, respectively (P=0.087). The number of distal anastomosis was comparable between the two groups (3.0±0.9 vs. 3.0±1.0, P=0.816). After PS matching, the incidence of major complications such as stroke (P>0.99) and new-onset dialysis (P=0.109) was comparable. During a median follow-up of 81.0 months (quartiles 1-3, 66.6-95.0 months), 118 patients died and the PS-matched models showed no significant between-group differences in the risk of overall death [hazard ratio (HR), 1.19; 95% confidence interval (CI), 0.72-1.95; P=0.507] and major adverse cardiac events (MACE) (HR, 1.49; 95% CI, 0.67-3.31; P=0.328).

Conclusions

The OPB strategy may be as safe and effective as the conventional strategy during CABG among patients with similar risk profiles. A prospective randomized trial is warranted to better ascertain the beneficial impact of OPB-CABG as both a viable and a durable alternative strategy to C-CABG.

Task-related changes in degree centrality and local coherence of the posterior cingulate cortex after major cardiac surgery in older adults

OBJECTIVES

Older adults often display postoperative cognitive decline (POCD) after surgery, yet it is unclear to what extent functional connectivity (FC) alterations may underlie these deficits. We examined for postoperative voxel-wise FC changes in response to increased working memory load demands in cardiac surgery patients and nonsurgical controls.

EXPERIMENTAL DESIGN

Older cardiac surgery patients (n = 25) completed a verbal N-back working memory task during MRI scanning and cognitive testing before and 6 weeks after surgery; nonsurgical controls with cardiac disease (n = 26) underwent these assessments at identical time intervals. We measured postoperative changes in degree centrality, the number of edges attached to a brain node, and local coherence, the temporal homogeneity of regional functional correlations, using voxel-wise graph theory-based FC metrics. Group × time differences were evaluated in these FC metrics associated with increased N-back working memory load (2-back > 1-back), using a two-stage partitioned variance, mixed ANCOVA.

PRINCIPAL OBSERVATIONS

Cardiac surgery patients demonstrated postoperative working memory load-related degree centrality increases in the left dorsal posterior cingulate cortex (dPCC; p < .001, cluster p-FWE < .05). The dPCC also showed a postoperative increase in working memory load-associated local coherence (p < .001, cluster p-FWE < .05). dPCC degree centrality and local coherence increases were inversely associated with global cognitive change in surgery patients (p < .01), but not in controls.

CONCLUSIONS

Cardiac surgery patients showed postoperative increases in working memory load-associated degree centrality and local coherence of the dPCC that were inversely associated with postoperative global cognitive outcomes and independent of perioperative cerebrovascular damage.

Lidocaine dose-response effect on postoperative cognitive deficit: meta-analysis and meta-regression

INTRODUCTION

The true influence of the perioperative intravenous lidocaine on the development of postoperative cognitive deficit (POCD) in coronary artery bypass grafting (CABG) remains controversial. The principal aim is to undertake a meta-regression to determine whether moderator variables mediate the relationship between lidocaine and POCD. Areas covered: We searched the Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2017) and systematically reviewed a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared infusion of lidocaine and placebo during cardiopulmonary bypass (CPB). Mantel-Haenszel risk ratio (MH RR) and corresponding 95% confidence interval (CI) was used to report the overall effect and meta-regression analysis. A total of 688 patients in five RCTs were included. POCD occurred in 34% of all cases. Perioperative lidocaine reduces POCD (MH RR 0.702 (95% CI: 0.541-0.909). Younger age, male gender, longer CPB and higher concentration of lidocaine significantly mediate the relationship between lidocaine and POCD in favour of the neuroprotective effect of lidocaine. Expert commentary: The neuroprotective effect of lidocaine on POCD is consistent in spite of longer CPB time. A higher concentration of lidocaine strengthened the neuroprotective effect of lidocaine.

Evaluation of the effects of a new series of SMTPs in the acetic acid-induced embolic cerebral infarct mouse model

We reported previously that Stachybotrys microspora triprenyl phenol-7 (SMTP-7) showed potential thrombolytic, anti-inflammatory and anti-oxidant effects that account for its excellent pharmacological activity such as having a wider therapeutic time window than tissue plasminogen activator (t-PA) and a significant protection against hemorrhage. The aim of the present study was to evaluate and compare the effect of a new series of SMTPs in the acetic acid-induced embolic cerebral infarct mouse model. Thrombotic occlusion was produced in mice by inducing the transfer of acetic acid-induced thrombi from the right common carotid artery into the brain. SMTPs were evaluated by their effect on reducing infarct area, neurological score and edema. Furthermore, plasmin formation, anti-inflammatory and anti-oxidant activities were assessed by fibrin zymography, measuring pro-inflammatory gene expression, and thiobarbituric acid reactive substances (TBARS) assay, respectively. Treatment with either SMTP-22 or SMTP-43 (10mg/kg), which have similar plasmin formation, anti-inflammatory and anti-oxidant activities to SMTP-7, resulted in reduced infarct area, neurological score and edema. Coexistence of all these three activities appears to be important for the treatment of embolic infarction because SMTP-6, SMTP-25, and SMTP-44D (10mg/kg), which are each missing at least one of the three functions, were not as effective. Therefore, these results indicate that SMTP-22 and SMTP-43 have potential as medicinal compounds for the treatment of embolic cerebral infarction.

Cerebral Microhemorrhage: A Frequent Magnetic Resonance Imaging Finding in Pediatric Patients after Cardiopulmonary Bypass

Objectives:

This study was undertaken to estimate the incidence and burden of cerebral microhemorrhage (CM) in patients with heart disease who underwent cardiopulmonary bypass (CPB), as detected on susceptibility-weighted imaging (SWI), a magnetic resonance (MR) sequence that is highly sensitive to hemorrhagic products.

Materials and Methods:

With Institutional Review Board waiver of consent, MR imaging (MRI) of a cohort of 86 consecutive pediatric patients with heart failure who underwent heart transplantation evaluation were retrospectively reviewed for CM. A nested case–control study was performed. The CPB group consisted of 23 pediatric patients with heart failure from various cardiac conditions who underwent CPB. The control group was comprised of 13 pediatric patients with similar cardiac conditions, but without CPB history. Ten patients in the CPB group were female (age: 5 days to 16 years at the time of the CPB and 6 days to 17 years at the time of the MRI). The time interval between the CPB and MRI ranged from 11 days to 4 years and 5 months. Six patients in the control group were female, age range of 2 days to 6 years old. The number of CM on SWI was counted by three radiologists (PK, EK and DK). The differences in number of CM between groups were tested for significance using Mann–Whitney U-test, α = 0.05. Using the univariate analysis of variance model, the differences in number of CM between groups were also tested with adjustment for age at MRI.

Results:

There are statistically significant differences in CM on SWI between the CPB group and control group with more CM were observed in the CPB group without and with adjustment for age at MRI (P < 0.001).

Conclusions:

Exposure of CPB is associated with increased prevalence and burden of CM among pediatric patients with heart failure.

Carotid artery disease and perioperative stroke risk after surgical aortic valve replacement: A nationwide inpatient sample analysis

To study the role of carotid stenosis (CS) and cerebrovascular disease as independent risk factors for perioperative stroke following surgical aortic valve replacement (SAVR). The National Inpatient Sample (NIS) database was used for our study. All patients who underwent SAVR from 1999 to 2011 were identified using ICD-9 codes. Univariate and multivariate analysis of baseline characteristics, Elixhauser comorbidities and other covariates were examined to identify independent predictors of perioperative strokes following SAVR. Data on 50,979 patients who underwent SAVR from 1999 to 2011 was obtained. The mean age of the study cohort was 60.5. The study patients were predominantly Caucasian (79.3%) and males (60.01%). The incidence of perioperative stroke was 2.48%. CS (OR 1.8, 95%CI 1.1-2.8, p=0.009) and cerebral arterial occlusion (OR 3.4, 95% CI 1.3-8.9) significantly increased perioperative stroke risk following SAVR. Infective endocarditis (OR 4.6, 95%CI 3.8-5.6, p=0.00) and neurological disorders (OR 4.8, 95% CI 4-5.8, p=0.00) appeared to be the strongest risk factors for strokes. Other risk factors found to be significant predictors of perioperative strokes (p<0.05) were - age, higher VWR scores, CS, cerebral arterial occlusion, infective endocarditis, DM, HTN, renal failure, neurological disorders, coagulopathy and hypothyroidsm. In conclusion, perioperative stroke risk has remained more or less constant despite advancements in surgical techniques with risk having gone up in patients <65years of age. CS and cerebral arterial occlusion significantly increase stroke risk following SAVR. Improved patient selection with pre-operative risk stratification and institution of preventive strategies are necessary to improve operative outcomes following SAVR.

Do lipid microemboli induce acute kidney injury during cardiopulmonary bypass?

BACKGROUND

Acute kidney injury (AKI) following cardiopulmonary bypass affects 5% of patients, representing significant postoperative morbidity and mortality. Animal models have shown an increased uptake of lipid microemboli (LME) into the renal vasculature, potentially indicating ischaemic causation. This study tested a new lipid filtration system (RemoweLL) against a conventional system with no lipid-depleting capacity to determine the efficacy of the filtration system and its effects on renal function.

METHODS

Thirty consecutive patients underwent coronary artery bypass graft surgery using either the RemoweLL filtration system (15 patients) or a conventional cardiopulmonary bypass circuit (15 patients). Renal function was assessed using cystatin C concentrations as a surrogate marker of glomerular injury, as well as perioperative glomerular filtration rate (GFR) and serum creatinine concentrations. Patients were defined as having acute renal injury if there was an increase in absolute serum creatinine ⩾3 mg/dL (26.4 µmol/L) or 1.5-fold increase from baseline as categorised using the AKIN criteria.

RESULTS

Postoperative differences in LME count between the two groups were highly significant [p<0.001]. Analysis of peak cystatin C concentrations showed significantly lower levels in the LME filtration group on the 2^nd postoperative morning [p=0.04]. Two-factor ANOVA revealed a trend towards interaction, but this failed to reach significance [p=0.06]. There were no differences throughout the study period in serum creatinine or GFR [p>0.05]. There were no differences in any of the serum or urinary electrolytes.

CONCLUSIONS

This study has shown a trend towards improved cystatin C removal with LME filtration; with significantly lower peak concentrations, although no further evidence of renoprotection could be demonstrated. Further research is warranted to establish possible renal benefits of LME filtration in patients undergoing cardiac surgery.

Revisiting the utility of technical performance scores following tetralogy of Fallot repair

OBJECTIVE

Although an important quality metric, current technical performance scores may not be generalizable and may omit operative factors that influence outcomes. We examined factors not included in current technical performance scores that may contribute to increased postoperative length of stay, major complications, and cost after primary repair of tetralogy of Fallot.

METHODS

This is a retrospective single site study of patients younger than age 2 years with tetralogy of Fallot undergoing complete repair between 2007 and 2015. Medical record data and discharge echocardiograms were reviewed to ascertain component and composite technical performance scores. Primary outcomes included postoperative length of stay, major complications, and total hospital costs. Multivariable logistic and linear regression identified determinants of each outcome.

RESULTS

Patient population (n = 115) had a median postoperative length of stay of 8 days (interquartile range, 6-10 days), and a median total cost of $71,147. Major complications occurred in 33 patients (29%) with 1 death. Technical performance scores assigned were optimum in 28 patients (25%), adequate in 59 patients (52%), and inadequate in 26 patients (23%). Neither technical performance score components nor composite scores were associated with increased postoperative length of stay. Optimum or adequate repairs versus inadequate had equal risk of a complication (P = .79), and equivalent mean total cost ($100,000 vs $187,000; P = .25). Longer cardiopulmonary bypass time per 1-minute increase (P < .01) was associated with longer postoperative length of stay and reintervention (P = .02). The need to return to bypass also increased total cost (P < .01).

CONCLUSIONS

Current tetralogy of Fallot technical performance scores were not associated with selected outcomes in our postoperative population. Although returning to bypass and bypass length are not included as components in the current score, these are important factors influencing complications and resource use in our population. Revisions anticipated from a prospective trial should consider including these variables.

Risk factors of sepsis after open congenital cardiac surgery in infants: a pilot study

Background: Postsurgical sepsis is one of the main causes of the high mortality and morbidity after open congenital heart surgery in infants.  This study aimed to evaluate the role of cardiopulmonary bypass duration, thymectomy, surgical complexity, and nutritional status on postsurgical sepsis after open congenital cardiac surgery in infants.Methods: A total of 40 patients <1 year of age with congenital heart disease, Aristotle Basic Score (ABS) ≥6 were followed for clinical and laboratory data before and after surgery until the occurrence of signs or symptoms of sepsis or until a maximum of 7 days after surgery. Bivariate analyses were performed. Variables with p≤0.200 were then included for logistic regression.Results: Duration of cardiopulmonary bypass ≥90 minutes was associated with 5.538 increased risk of postsurgical sepsis in comparison to those ≤90 minutes (80% vs 25%, RR=5.538, p=0.006). No association was observed between the incidence of postsurgical sepsis with poor nutritional status (86% vs 84%, RR=1.059, p=1.000), thymectomy (and 50% vs 76%, RR=0.481, p=0.157), and Aristotle Basic Score (p=0.870).Conclusion: Cardiopulmonary bypass time influences the incidence of sepsis infants undergoing open congenital cardiac surgery. Further studies are needed to elaborate a number of risk factors associated with the incidence of sepsis in this population.

A Systematic Approach to the Understanding and Redesigning of Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) is a highly complex process. We developed a system to capture and study detailed information during cardiac surgery that serves as a framework for understanding variation that occurs during CPB. The system allows the surgical team to link unwanted variation (ie, hypotension) and unwanted events (ie, the production of microemboli) to the processes of care. A more thorough understanding of embolic activity and hemodynamic aberrations, precursors to both stroke and subtle neurologic injury, that occur during CPB, will allow the surgical team to identify high leverage, modifiable aspects of care and abate these precursors to patient injury. Multimodality simultaneous monitoring and recording of physiologic parameters, emboli in the CPB circuit and in the middle cerebral arteries, and cerebral NIRS during surgery was carried out in patients undergoing open heart surgery with CPB. A system was designed that captures physiologic data from the patient monitors and the heart-lung machine at 20-second intervals and time synchronizes all measures with a video recording of the surgical procedure. Emboli counts count in the CPB circuit and right and left middle cerebral arteries were continuously recorded. Video recordings depicting various surgical and perfusion techniques with associated embolic activity were provided to the surgical team. Wide variation in embolic counts, cerebral blood flow velocity, and physiologic parameters were observed. Periods of embolic activity and cerebral desaturation could be related to surgical and CPB processes of care. We have identified increased emboli counts in the CPB circuit and in the middle cerebral arteries related to the method of venous drainage, manipulation of the aorta, and anastomotic techniques. se of this model provides the surgical team detailed information about these precursors to neurologic injury. This system provides a systematic approach to the understanding and redesigning of CPB.

Outcomes in patients undergoing complex cardiac repairs with cross clamp times over 300 minutes

BACKGROUND

Long cross clamp times have been associated with poor clinical outcomes, yet some patients require extremely long ischemic times to repair complex surgical problems. The purpose of this study was to examine short and mid-term survival and to identify risk factors for mortality and morbidity in patients with cross clamp times greater than or equal to 300 min.

METHODS

Review of our institution's Society of Thoracic Surgeons database identified 202 patients who underwent surgical procedures necessitating aortic cross clamp times 300 min or greater between 2001 and 2012. Short-term (30-day) clinical outcomes were derived from this database and survival was assessed utilizing the Social Security Death Index. Univariate and multivariate analyses were used to determine the relationship between independent variables and mortality and postoperative outcomes.

RESULTS

The average age of the patients was 69.5 ± 10.6 (mean ± standard deviation) years and the mean ejection fraction was 52 ± 12 %. 70.3 % of patients were male. Mean cross clamp time was 346 ± 45 min, and total bypass time was 421 ± 70 min. Thirty-day mortality was 12.4 %. The incidence of bleeding and stroke were 6.4 % and 4.0 % respectively. Prolonged ventilation occurred in 26.7 % of patients, and incidence of renal failure was 10.4 %. One, three, five, and seven year survival of the patients who survived the first 30 days post-surgery was 91.9 %, 83.2 %, 75.6 % and 65.7 % respectively. Proportional hazards analysis determined that the statistically significant hazard ratios for mid-term mortality for female gender, age, and prolonged postoperative ventilation were 2.11, 1.04 and 2.72, respectively (p < 0.05 for each).

CONCLUSIONS

Cardiac procedures requiring extremely long ischemic times have significant early mortality and morbidity. However, mid-term survival in the patients who survive is good. Decision-making regarding operability in complex cases should allow for long ischemic times.

Comparison of two different extracorporeal circuits on cerebral embolization during cardiopulmonary bypass in children

Objective: To compare the effect of two different extra-corporeal circuits on the counts of high-intensity transient signals (HITS) during pediatric cardiopulmonary bypass (CPB). Methods: Transcranial Doppler was used to detect HITS associated with extracorporeal sources during the period of aortic crossclamping in the middle cerebral artery of children undergoing CPB. Based on body size, children were assigned one of two extracorporeal circuits (A or B). Circuit A included a D-705 oxygenator and associated reservoir, and circuit B included a Lilliput oxygenator and reservoir. Patients were further classified into two groups according to the complexity of surgical repair: single simple lesions or multiple complex lesions. Results: We studied 109 pediatric patients. Surgery for multiple complex lesions was associated with longer periods of aortic crossclamping and CPB (p <0.0001). The median count of extra-corporeal HITS was 12 (25th, 75th percentiles: 3, 51). The type of extracorporeal circuit (p=0.012) and the complexity of surgical repair (p <0.0001) had an effect on the HITS counts. The use of circuit A was associated with higher HITS counts during surgery for multiple complex lesions compared to single simple lesions (p <0.0001). Conversely, no differences were found with the use of circuit B between these two surgical groups (p >0.25). During surgery for multiple complex lesions, patients treated with circuit A showed higher HITS counts than those with circuit B (p <0.01), but there were no circuit-related differences in HITS counts (p=0.30) during single simple lesions. Conclusion: Variations in the design characteristics of extracorporeal circuits can increase cerebral emboli during CPB in children. This may be related to the reduced ability of some circuits to remove emboli during long periods of CPB for complex congenital heart-surgery.