Basics of cardiopulmonary bypass

Cardiopulmonary bypass associated acute kidney injury: better understanding and better prevention

Cardiopulmonary bypass (CPB) is a common technique in cardiac surgery but is associated with acute kidney injury (AKI), which carries considerable morbidity and mortality. In this review, we explore the range and definition of CPB-associated AKI and discuss the possible impact of different disease recognition methods on research outcomes. Furthermore, we introduce the specialized equipment and procedural intricacies associated with CPB surgeries. Based on recent research, we discuss the potential pathogenesis of AKI that may result from CPB, including compromised perfusion and oxygenation, inflammatory activation, oxidative stress, coagulopathy, hemolysis, and endothelial damage. Finally, we explore current interventions aimed at preventing and attenuating renal impairment related to CPB, and presenting these measures from three perspectives: (1) avoiding CPB to eliminate the fundamental impact on renal function; (2) optimizing CPB by adjusting equipment parameters, optimizing surgical procedures, or using improved materials to mitigate kidney damage; (3) employing pharmacological or interventional measures targeting pathogenic factors.

Relation Between Multiplication of Venous Carbon Dioxide Partial Pressure (PvCO2) and the Ratio of Gas Flow to Pump Flow (Ve/Q) with Hyperlactatemia During Cardiopulmonary Bypass

BACKGROUND

The incidence of hyperlactatemia due to hypoperfusion during cardiopulmonary bypass (CPB) increases morbidity. Carbon dioxide production during CPB is one of the lactate production markers, in addition to other markers such as delivery oxygen (DO2), oxygen consumption (VO2), mixed vein oxygen saturation (SvO2), and oxygen extraction ratio (O2ER).

METHOD

This observational analytic study was conducted on 40 adult cardiac surgery patients using a CPB machine. Initial lactate is taken when entering CPB and final lactate is examined 15 min after coming off bypass. The values of DO2, VO2, SvO2, VCO2, respiratory quotient (RQ), DO2/VCO2, PvCO2 × Ve/Q were calculated from the results of blood and venous gas analysis 1 h after entering CPB in the nadir of core temperature and lowest pump flow.

RESULT

The multivariate test showed that the value of PvCO2 × Ve/Q was more effective than other oxygenation and carbon dioxide parameters in predicting an increase in the percentage of lactate. Each increase of 1 mmHg PvCO2 ×× Ve/Q can predict a final lactate increase of 29% from the initial lactate. The high PvCO2 × Ve/Q value is also the strongest correlation factor for the incidence of hyperlactatemia after CPB (final lactate >3 mmol/L). The cutoff value of this marker is >19.3 mmHg, which has a sensitivity of 100% and a specificity of 55.6% with a strong correlation value.

CONCLUSION

The PvCO2 × Ve/Q value proved to be one of the significant markers in predicting hyperlactatemia during cardiac surgery using CPB.

Heparin-Bead Extraction Enhanced Fluorogenic Aptamer-Thrombin Composite Reporter Enables Sensitive and Rapid Detection of Functional Antithrombin

Antithrombin (AT) deficiency in the extracorporeal circulation during cardiac surgery leads to uncontrolled inflammation and vascular damage in patients. AT levels decrease in sepsis, major trauma, extracorporeal membrane oxygenation, and eclampsia. Monitoring plasma AT levels facilitates the accurate restoration of AT to baseline values through precise supplementation. Traditional methods of chromogenic assay and enzyme-linked immunosorbent assay (ELISA) kits encounter challenges, such as interference, inconsistency, and delayed response times, making real-time, reliable antithrombin monitoring a clinical gap. To address this critical need, we develop a heparin-bead extraction enhanced fluoroGenic aptamer-thrombin composite reporter (HExGATOR) for the rapid, sensitive, and precise detection of functional AT in plasma. Our design employs thrombin-binding aptamers and a fluorescence "turn on" technology such that a signal is produced upon the interaction of AT with the otherwise "turned off" aptamer-thrombin complex. The prominent signal-background interference originating from plasma is remarkably diminished by using a heparin-bead solid-phase extraction of AT. We achieved highly sensitive and rapid detection of AT in 5 to 20 min with a limit of detection of 15.11 nM. This approach offers a promising alternative to traditional AT tests in clinical settings, potentially facilitating personalized anticoagulant therapy.

The Surgical Outcome of Infective Endocarditis in South Africa over 10 Years: A Retrospective Review

Objectives: There is a paucity of data on the outcome of left-sided cardiac valve surgery for infective endocarditis in South Africa. It is hypothesized that outcomes may be poorer compared to international standards due to differences in disease burden, timing of surgery, organism prevalence, and co-morbidities. Method: This is a retrospective study of 160 patients with left heart valve endocarditis who underwent cardiac surgery from January 2010 to December 2019. Demographic, operative, and admission-related parameters were assessed to determine their association with all-cause mortality during the early post-operative (<30 days) and late post-operative (>30 days) periods. Results: Early post-operative mortality (<30 days) was 8.8% and late post-operative mortality (>30 days) was 13.1%. Late survival showed 77.5% of the patients were alive with a mean follow-up period of 41 months. Increased age (p = 0.04), critical illness (p < 0.001), and higher urgency of intervention (p < 0.001) were associated with higher early post-operative mortality. Peri-operative organ failure, including cardiac (p = 0.025), renal (p = 0.016), and respiratory failure (p < 0.001), contributed significantly to both early and late mortality. Pre-operative antibiotics for fewer days (p = 0.024), ongoing sepsis (p = 0.022), and para-valvular extension (p = 0.046) were associated with higher early mortality. Conclusions: Infective endocarditis is a common indication for cardiac valve surgery in South Africa. Goal-directed medical management and clinical optimization prior to surgery were crucial to achieving better outcomes. Salvage procedures and critical illness with organ failure prior to surgery were associated with poorer outcomes. Despite unique challenges, cardiac surgery for infective endocarditis at Tygerberg Hospital compares favorably to international standards.

Five historical innovations that have shaped modern cardiothoracic surgery

Throughout history, many innovations have contributed to the development of modern cardiothoracic surgery, improving patient outcomes and expanding the range of treatment options available to patients. This article explores five key historical innovations that have shaped modern cardiothoracic surgery: cardiopulmonary bypass, surgical pacemakers, video assisted thoracic surgery, robotic surgery and mechanical circulatory support. We will review the development, impact and significance of each innovation, highlighting their contributions to the field of cardiothoracic surgery and their ongoing relevance in contemporary and perioperative practice.

Association of Weight-indexed Conventional Ultrafiltration Volume with Post-operative Lactate in Patients Undergoing Cardiopulmonary Bypass

Background

Conventional ultrafiltration (CUF) during cardiopulmonary bypass (CPB) is utilized to minimize hemodilution. However, removing high volumes leads to tissue hypoperfusion by activating the anaerobic glycolysis pathways. This study aimed to determine the association between weight-indexed CUF volumes and lactate in patients who underwent coronary artery bypass grafting (CABG).

Methods

In this single-center retrospective study, 641 CABG patients, who were referred to Al-Zahra Hospital (Shiraz, Iran) and underwent CPB, during 2019-2021, were recruited. Peri-operative parameters were extracted from the patient's records. The patients with non-elective status, pre-existing liver and renal diseases, ejection fraction<35%, and repeated sternotomy were excluded from the study. An increase in post-operative lactate level≥4 mmol/L after 6 hours was defined as hyperlactatemia (HL). To predict HL, univariable and multiple logistic regression modeling, while controlling confounding factors, were employed.

Results

The patients' mean age was 58.8±11.1 years, and 39.2% were women. The incidence of HL was 14.5% (93 patients). There was a significant association between weight-indexed CUF volume and HL. The volume removed in the HL patients was almost doubled (43.37±11.32 vs. 21.41±8.15 mL/Kg, P<0.001), and the higher the weight-indexed CUF volume, the more likely to develop an HL at a rate of 1.38 (Odds ratio=1.38 [1.27-1.49], 95% CI, P<0.001). Furthermore, the multiple logistic regression model showed that HL was associated with the lowest mean arterial pressure (MAP) during CPB.

Conclusion

A higher volume of ultrafiltration was associated with increased post-operative serum lactate levels.

Acute type A aortic dissection in patients with non-prior cardiac surgery vs. prior cardiac surgery: a systematic review and meta-analysis

Background

Patients with prior cardiac surgery undergoing acute type A aortic dissection (ATAAD) are thought to have worse clinical outcomes as compared to the patients without prior cardiac surgery.

Aim

To compare the safety and efficacy of ATAAD in patients with prior cardiac surgery.

Methods

We systematically searched PubMed, Cochrane Library and Google Scholar from database inception until April 2024. We included nine studies which consisted of a population of 524 in the prior surgery group and 5,249 in the non-prior surgery group. Our primary outcome was mortality. Secondary outcomes included reoperation for bleeding, myocardial infarction, stroke, renal failure, sternal wound infection, cardiopulmonary bypass (CPB) time, cross-clamp time, hospital stay, and ICU stay.

Results

Our pooled estimate shows a significantly lower rate of mortality in the non-prior cardiac surgery group compared to the prior cardiac surgery group (RR = 0.60, 95% CI = 0.48-0.74). Among the secondary outcomes, the rate of reoperation for bleeding was significantly lower in the non-prior cardiac surgery group (RR = 0.66, 95% CI = 0.50-0.88). Additionally, the non-prior cardiac surgery group had significantly shorter CPB time (MD = -31.06, 95% CI = -52.20 to -9.93) and cross-clamp time (MD = -21.95, 95% CI = -42.65 to -1.24). All other secondary outcomes were statistically insignificant.

Conclusion

Patients with prior cardiac surgery have a higher mortality rate as compared to patients who have not undergone cardiac surgery previously. Patients with prior cardiac surgery have higher mortality and longer CPB and cross-clamp times. Tailored strategies are needed to improve outcomes in this high-risk group.

Cardioprotection in cardiovascular surgery

Since the invention of cardiopulmonary bypass, cardioprotective strategies have been investigated to mitigate ischemic injury to the heart during aortic cross-clamping and reperfusion injury with cross-clamp release. With advances in cardiac surgical and percutaneous techniques and post-operative management strategies including mechanical circulatory support, cardiac surgeons are able to operate on more complex patients. Therefore, there is a growing need for improved cardioprotective strategies to optimize outcomes in these patients. This review provides an overview of the basic principles of cardioprotection in the setting of cardiac surgery, including mechanisms of cardiac injury in the context of cardiopulmonary bypass, followed by a discussion of the specific approaches to optimizing cardioprotection in cardiac surgery, including refinements in cardiopulmonary bypass and cardioplegia, ischemic conditioning, use of specific anesthetic and pharmaceutical agents, and novel mechanical circulatory support technologies. Finally, translational strategies that investigate cardioprotection in the setting of cardiac surgery will be reviewed, with a focus on promising research in the areas of cell-based and gene therapy. Advances in this area will help cardiologists and cardiac surgeons mitigate myocardial ischemic injury, improve functional post-operative recovery, and optimize clinical outcomes in patients undergoing cardiac surgery.

Population Pharmacokinetics and Target Attainment of Allopurinol and Oxypurinol Before, During, and After Cardiac Surgery with Cardiopulmonary Bypass in Neonates with Critical Congenital Heart Disease

BACKGROUND

The CRUCIAL trial (NCT04217421) is investigating the effect of postnatal and perioperative administration of allopurinol on postoperative brain injury in neonates with critical congenital heart disease (CCHD) undergoing cardiac surgery with cardiopulmonary bypass (CPB) shortly after birth.

OBJECTIVE

This study aimed to characterize the pharmacokinetics (PK) of allopurinol and oxypurinol during the preoperative, intraoperative, and postoperative phases in this population, and to evaluate target attainment of the current dosing strategy.

METHODS

Nonlinear mixed-effects modeling was used to develop population PK models in 14 neonates from the CRUCIAL trial who received up to five intravenous allopurinol administrations throughout the postnatal and perioperative periods. Target attainment was defined as achieving an allopurinol concentration >2 mg/L in at least two-thirds of the patients during the first 24 h after birth and between the start and 36 h after cardiac surgery with CPB.

RESULTS

A two-compartment model for allopurinol was connected to a one-compartment model for oxypurinol with an auto-inhibition effect on the conversion, which best described the PK. In a typical neonate weighing 3.5 kg who underwent cardiac surgery at a postnatal age (PNA) of 5.6 days, the clearance (CL) of allopurinol and oxypurinol at birth was 0.95 L/h (95% confidence interval 0.75-1.2) and 0.21 L/h (0.17-0.27), respectively, which subsequently increased with PNA to 2.97 L/h and 0.41 L/h, respectively, before CPB. During CPB, allopurinol and oxypurinol CL decreased to 1.38 L/h (0.9-1.87) and 0.12 L/h (0.05-0.22), respectively. Post-CPB, allopurinol CL increased to 2.21 L/h (1.74-2.83), while oxypurinol CL dropped to 0.05 L/h (0.01-0.1). Target attainment was 100%, 53.8%, and 100% at 24 h postnatally, 24 h after the start of CPB, and 36 h after the end of cardiac surgery, respectively. The combined concentrations of allopurinol and oxypurinol maintained ≥ 90% inhibition of xanthine oxidase (IC90XO) throughout the postnatal and perioperative period.

CONCLUSIONS

The minimal target concentration of allopurinol was not achieved at every predefined time interval in the CRUCIAL trial; however, the dosing strategy used was deemed adequate, since it yielded concentrations well exceeding the IC90XO. The decreased CL of both compounds during CPB suggests influence of the hypothermia, hemofiltration, and the potential sequestration of allopurinol in the circuit. The reduced CL of oxypurinol after CPB is likely attributable to impaired kidney function.

Population pharmacokinetic modeling of sufentanil in adult Korean patients undergoing cardiopulmonary bypass surgery

Sufentanil is frequently used as an anesthetic agent in cardiac surgery owing to its cardiovascular safety and favorable pharmacokinetics. However, the pharmacokinetics profiles of sufentanil in patients undergoing cardiopulmonary bypass (CPB) surgery remain less understood, which is crucial for achieving the desired level of anesthesia and mitigating surgical complications. Therefore, this study aimed to develop a population pharmacokinetic model of sufentanil in patients undergoing CPB surgery and elucidate the clinical factors affecting its pharmacokinetic profile. Adult patients who underwent cardiac surgery with CPB and were administered sufentanil for anesthesia were enrolled. Arterial blood samples were collected to quantify plasma concentrations of sufentanil and clinical laboratory parameters, including inflammatory cytokines. A population pharmacokinetic model was established using nonlinear mixed-effects modeling. Simulations were performed using the pharmacokinetic parameters of the final model. Overall, 20 patients were included in the final analysis. Sufentanil pharmacokinetics were modeled using a two-compartment model, accounting for CPB effects. Sufentanil clearance increased 2.80-fold during CPB and warming phases, while the central compartment volume increased 2.74-fold during CPB. CPB was a significant covariate affecting drug clearance and distribution volume. No other significant covariates were identified despite increased levels of the inflammatory cytokines, including IL-6, IL-8, and TNF-α during CPB. The simulation indicated a 30 μg loading dose and 40 μg/h maintenance infusion for target-controlled infusion. Additionally, a bolus dose of 60 μg was added at CPB initiation to adjust for exposure changes during this phase. Considering the target sufentanil concentrations, a uniform dosing regimen was acceptable for effective analgesia.

Intraoperative Aortic Dissection in a Case of Aneurysmal Dilatation of the Ascending Aorta Posted for Surgery

ABSTRACT

Intraoperative aortic dissection is a life-threatening emergency. The prognosis of patients with aortic dissection has markedly improved in recent years due to prompt diagnosis and the institution of effective medical and surgical therapy. Transesophageal echocardiography (TEE) is helpful in the evaluation of this life-threatening disorder.

Successful Kidney Donation Following Long-Term Normothermic Regional Perfusion: Challenges of the First Uncontrolled Donation After Circulatory Death in Iran

The global organ donation crisis continues to escalate despite advancements in medical procedures. Uncont-rolled donation after circulatory death provides an alternative method to increase the donor pool, especially for kidney transplants. This case study from Iran offers insights into the complex, yet essential, facets of organ procurement under uncontrolled donation after circulatory death protocols. A 38-year-old woman experienced a severe cerebrovascular accident and subsequent cardiac arrest. She was declared for uncontrolled donation after circulatory death, and her organs were preserved using cardiopulmonary bypass for 6 hours. Notably, her kidneys were successfully removed and transplanted into 2 recipients: a 43-year-old man with chronic kidney disease due to hypertension and a 48-year-old man with chronic kidney disease associated with diabetes mellitus. The first recipient experienced initial complications with kidney function that required a prolonged hospital stay, but he eventually exhibited improved renal function. The second recipient experienced fluctuating kidney function initially, which stabilized, demonstrating the practical viability of kidneys procured through uncontrolled donation after circulatory death. This pioneering case in Iran underscores the potential of uncontrolled donation after circulatory death to expand organ procurement and addresses critical medical, ethical, and legal challenges. We emphasize the need for refined protocols that reduce wait times and improve organ viability, thereby contributing to the broader organ donation network. Future research should focus on enhancement of normothermic regional perfusion techniques to improve outcomes for both donors and recipients.

Factors associated with early postoperative mortality after total anomalous pulmonary venous connection repair: A retrospective cohort study

Total anomalous pulmonary venous connection (TAPVC) is a rare congenital defect where pulmonary venous plexus fails to connect with the left atrium (LA). Surgical repair is the primary treatment for TAPVC, but factors influencing outcomes are not fully understood. This study investigates the early outcomes of surgical repair for TAPVC and associated factors. A retrospective cohort analysis was conducted on TAPVC patients who underwent surgical repair between 2012 and 2022. Data were collected from medical records and supplemented with phone call validation. Demographic characteristics, surgical data, diagnostic tests, and outcomes were analyzed. Statistical analysis included chi-square, t-tests, and multivariate logistic regression using SPSS. A total of 88 patients underwent surgical repair for TAPVC, resulting in a mortality rate of 21.6%. Weight and bypass time were significantly associated with patient survival. Female patients had a higher likelihood of death. The anatomic type did not significantly influence mortality. Patients with pulmonary venous obstruction (PVO) experienced a higher mortality rate. Notably, ligation of the vertical vein in supracardiac and infracardiac types was associated with lower mortality. In conclusion, our study identifies several key factors contributing to higher mortality rates following TAPVC surgery, including low weight, female gender, prolonged bypass time, and preoperative vein obstruction. Highlighting the significance of surgical technique, particularly the sutureless approach, we advocate for its meticulous consideration to achieve improved outcomes. Furthermore, our findings indicate a potential decrease in mortality associated with vertical vein ligation, which may mitigate the risk of post-repair heart failure. We suggest further rigorous studies to gain comprehensive insights into TAPVC surgical interventions.

Intravascular Ultrasound-Guided Stenting of the Celiac Artery for Hepatic Hypoperfusion After Acute Type A Aortic Dissection: A Case Report

Type A aortic dissection is a life-threatening emergency requiring prompt surgical treatment. The dissection itself and use of cardiopulmonary bypass can lead to further postoperative complications, including aortic branch occlusion, thrombosis, ischemia, and fatal end-organ damage. Celiac artery occlusion with consequent hepatic malperfusion is one feared complication of aortic dissection, which requires urgent surgical intervention. Optimal management of celiac artery dissection in the setting of type A aortic dissection has not yet been described in the literature. In this report, we describe a 39-year-old female patient with hypertension who was found to have celiac artery dissection and impending hepatic failure less than 48 hours after emergent ascending aortic replacement for type A aortic dissection. Placement of an ultrasound-guided endovascular celiac artery stent enabled reperfusion of the liver, ultimately saving the patient's life.

Prevalence and clinical implications of heightened plastic chemical exposure in pediatric patients undergoing cardiopulmonary bypass

BACKGROUND

Phthalate chemicals are used to manufacture plastic medical products, including many components of cardiopulmonary bypass (CPB) circuits. We aimed to quantify iatrogenic phthalate exposure in pediatric patients undergoing cardiac surgery and examine the link between phthalate exposure and postoperative outcomes.

STUDY DESIGN AND METHODS

The study included pediatric patients undergoing (n=122) unique cardiac surgeries at Children's National Hospital. For each patient, a single plasma sample was collected preoperatively and two additional samples were collected postoperatively upon return from the operating room and the morning after surgery. Concentrations of di(2-ethylhexyl) phthalate (DEHP) and its metabolites were quantified using ultra high-pressure liquid chromatography coupled to mass spectrometry.

RESULTS

Patients were subdivided into three groups, according to surgical procedure: (1) cardiac surgery not requiring CPB support, (2) cardiac surgery requiring CPB with a crystalloid prime, and (3) cardiac surgery requiring CPB with red blood cells (RBCs) to prime the circuit. Phthalate metabolites were detected in all patients, and postoperative phthalate levels were highest in patients undergoing CPB with an RBC-based prime. Age-matched (<1 year) CPB patients with elevated phthalate exposure were more likely to experience postoperative complications. RBC washing was an effective strategy to reduce phthalate levels in CPB prime.

DISCUSSION

Pediatric cardiac surgery patients are exposed to phthalate chemicals from plastic medical products, and the degree of exposure increases in the context of CPB with an RBC-based prime. Additional studies are warranted to measure the direct effect of phthalates on patient health outcomes and investigate mitigation strategies to reduce exposure.

The Efficacy of Tranexamic Acid in Reducing Perioperative Drainage in Cardiac Surgery with Cardiopulmonary Bypass

INTRODUCTION

Although cardiopulmonary bypass procedures remain a critical treatment option for heart disease, they come with risks, including hemorrhage. Tranexamic acid is known to reduce morbidity and mortality in surgical hemorrhage.

OBJECTIVE

This study aimed to evaluate the efficacy of tranexamic acid, which is routinely used to treat hemorrhage, in decreasing the amount of intraoperative and postoperative drainage.

METHOD

A total of 80 patients who underwent cardiac surgery with cardiopulmonary bypass were included in this retrospective study. Forty patients who received tranexamic acid during the operation were assigned to Group 1, while 40 patients who did not receive tranexamic acid were assigned to Group 2. Patient data were collected from the hospital computer system and/or archive records after applying exclusion criteria, and the data were recorded. Statistical analyses were then performed to compare the data.

RESULTS

Age, sex, height, weight, body surface area, flow, and ejection fraction percentages, preoperative hematological parameters, and intraoperative variables (except tranexamic acid) were similar between the groups (P>0.05). However, there were statistically significant differences between the groups in terms of intraoperative (through the heart-lung machine) and postoperative red blood cell transfusion rates, intraoperative and postoperative bleeding drainage amounts, as well as postoperative hematocrit, hemoglobin, platelet, and red blood cell levels (P<0.05).

CONCLUSION

We concluded that intraoperative and postoperative use of tranexamic acid in patients who underwent coronary artery bypass grafting with cardiopulmonary bypass has positive effects on hematological parameters, reducing blood product use, and bleeding drainage amount.

Navigating missing link: innovative cannulation for robotic mitral valve repair in the absence of inferior vena cava

Cardiac surgeries often require the use of cardiopulmonary bypass to allow visualization and manipulation of tissues. Vascular anomalies may impose challenges with access configuration. A patient was evaluated for robot-assisted mitral valve repair and found to have an atretic inferior vena cava secondary due to chronic occlusion. The patient was cannulated arterially through the left common femoral artery, and two cannulation sites were applied for venous drainage: the right intrajugular vein and a second percutaneous access site directly into the right atrium through the chest wall. The procedure was completed without immediate complications, and the patient's perioperative course was unremarkable.

Mini Aortic Valve Replacement Converted to Bentall Procedure Secondary to Chronic Type A Aortic Dissection

In our case, a 46-year-old female with severe aortic insufficiency presented for minimally invasive aortic valve replacement. The patient was taken to the operating room, where transesophageal echocardiography showed severe aortic regurgitation with prolapse of the non-coronary cusp. The patient was placed on a cardiopulmonary bypass machine with peripheral cannulation. The aorta was cross-clamped, and an aortotomy was made. Despite multiple attempts, the left main coronary ostium was not visible. A sternotomy was quickly performed, and a newly discovered chronic type A dissection, obscuring the left main coronary artery, was found. Seventeen minutes after the cross-clamp was placed, the left main was transected, and cardioplegia was delivered. The patient then underwent a Bentall procedure with an aortic valve and root replacement.

Pro: Individualized Optimal Perfusion Pressure-Maximizing Patient Care During Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) has revolutionized cardiac surgery but poses challenges such as hemodynamic instability and adverse clinical outcomes. Achieving optimal perfusion during CPB ensures adequate oxygen delivery to vital organs. Although mean arterial pressure is a key determinant of perfusion pressure, clear guidelines for optimal perfusion have yet to be established. Autoregulation, the organ's ability to maintain consistent blood flow, plays a vital role in perfusion. Individual variability in autoregulation responses and intraoperative factors necessitate an individualized approach to determining the autoregulation range. Continuous assessment of autoregulation during surgery allows for personalized perfusion targets, optimizing organ perfusion. Exploring techniques like multimodal intravenous anesthesia guided by electroencephalogram can enhance perfusion maintenance within the auto-regulatory range. By adopting an individualized approach to perfusion targets on CPB, we can improve outcomes and enhance patient care.

Novel Strategies to Improve the Cardioprotective Effects of Cardioplegia

The use of cardioprotective strategies as adjuvants of cardioplegic solutions has become an ideal alternative for the improvement of post-surgery heart recovery. The choice of the optimal cardioplegia, as well as its distribution mechanism, remains controversial in the field of cardiovascular surgery. There is still a need to search for new and better cardioprotective methods during cardioplegic procedures. New techniques for the management of cardiovascular complications during cardioplegia have evolved with new alternatives and additives, and each new strategy provides a tool to neutralize the damage after ischemia/reperfusion events. Researchers and clinicians have committed themselves to studying the effect of new strategies and adjuvant components with the potential to improve the cardioprotective effect of cardioplegic solutions in preventing myocardial ischemia/reperfusion-induced injury during cardiac surgery. The aim of this review is to explore the different types of cardioplegia, their protection mechanisms, and which strategies have been proposed to enhance the function of these solutions in hearts exposed to cardiovascular pathologies that require surgical alternatives for their corrective progression.

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

Objective

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

Patients and Methods

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

Results

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

Conclusion

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

Prothrombin Complex Concentrate versus Fresh Frozen Plasma in Adult Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-Analysis

Background

Prothrombin complex concentrate (PCC) and fresh frozen plasma (FFP) are commonly used to manage bleeding in patients during cardiac surgery. However, the relative efficacy and safety of these 2 strategies remain uncertain.

Methods

MEDLINE, Embase, and Cochrane were searched for studies comparing PCC and FFP in patients who underwent cardiac surgery complicated by bleeding. Review Manager (RevMan) ver. 5.4 (Nordic Cochrane Centre, The Cochrane Collaboration) was used for statistical analysis. Binary and continuous outcomes were compared using pooled risk ratios and mean differences, respectively. The meta-analysis protocol was registered in the International Prospective Register of Systematic Reviews under protocol number CRD42022379144.

Results

We included 8 studies with 1,500 patients, of whom 613 (40.9%) received PCC. The mean follow-up period ranged from 28 to 90 days. The PCC group had significantly lower chest tube drainage at 24 hours (mean difference [MD], -148.50 mL; 95% CI, -253.02 to -43.99 mL; p=0.005; I2=42%). Fewer units of red blood cells (RBCs) were transfused within the first 24 hours (MD, -1.02 units; 95% CI, -1.81 to -0.24 units; p=0.01; I2=56%), and fewer patients required RBC transfusion within the first 24 hours (risk ratio, 0.85; 95% CI, 0.78-0.93; p<0.007; I2=45%) in the PCC group. There were no statistically significant differences in secondary outcomes. Nonetheless, a subgroup analysis of randomized controlled trials failed to corroborate the results obtained from the main analysis.

Conclusion

Our findings suggest that PCC can be effective, without increased adverse events, when compared with FFP in patients undergoing cardiac surgery complicated by bleeding.

Unlocking the potential of deferoxamine: a systematic review on its efficacy and safety in alleviating myocardial ischemia-reperfusion injury in adult patients following cardiopulmonary bypass compared to standard care

BACKGROUND

Reperfusion injury, characterized by oxidative stress and inflammation, poses a significant challenge in cardiac surgery with cardiopulmonary bypass (CPB). Deferoxamine, an iron-chelating compound, has shown promise in mitigating reperfusion injury by inhibiting iron-dependent lipid peroxidation and reactive oxygen species (ROS) production.

OBJECTIVES

The objective of our study was to analyze and evaluate both the efficacy and safety of a new and promising intervention, that is, deferoxamine for ischemia-reperfusion injury (I/R).

DESIGN

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines are used to perform the study.

DATA SOURCES AND METHODS

We conducted a systematic review following PRISMA guidelines to assess the efficacy and safety of deferoxamine in reducing I/R injury following CPB. A comprehensive search of electronic databases, namely, PubMed, Scopus, and Embase, yielded relevant studies published until August 18, 2023. Included studies evaluated ROS production, lipid peroxidation, cardiac performance, and morbidity outcomes.

RESULTS

(a) ROS production: Multiple studies demonstrated a statistically significant decrease in ROS production in patients treated with deferoxamine, highlighting its potential to reduce oxidative stress. (b) Lipid peroxidation: Deferoxamine was associated with decreased lipid peroxidation levels, indicating its ability to protect cardiac tissue from oxidative damage during CPB. (c) Cardiac performance: Some studies reported improvements in left ventricular ejection fraction and wall motion score index with deferoxamine.

CONCLUSION

Our review shows that deferoxamine is an efficacious and safe drug that can be used to prevent myocardial I/R injury following CPB. It also highlights the need for trials on a larger scale to develop potential strategies and guidelines on the use of deferoxamine for I/R injury.

Intraoperative Extracorporeal Support during Lung Transplantation: Not Just for the High-Risk Patient

The use of intraoperative mechanical support during lung transplantation has traditionally been a controversial topic. Trends for intraoperative mechanical support strategies swing like a pendulum. Historically, cardiopulmonary bypass (CPB) was the modality of choice during transplantation. It provides full hemodynamic support including oxygenation and decarboxylation. Surgical exposure is improved by permitting the drainage of the heart and provides more permissive retraction. CPBs contain drainage reservoirs with hand-held pump suction catheters promoting blood conservation through collection and re-circulation. But CPB has its disadvantages. It is known to cause systemic inflammation and coagulopathy. CPB requires high doses of heparinization, which increases bleeding risks. As transplantation progressed, off-pump transplantation began to trend as a preferable option. ECMO, however, has many of the benefits of CPB with less of the risk. Outcomes were improved with ECMO compared to CPB. CPB has a higher blood transfusion requirement, a higher need for post-operative ECMO support, a higher re-intubation rate, high rates of kidney injury and need for hemodialysis, longer ICU stays, higher incidences of PGD grade 3, as well as overall in-hospital mortality when compared with ECMO use. The focus now shifts to using intraoperative mechanical support to protect the graft, helping to reduce ischemia-reperfusion injury and allowing for lung protective ventilator settings. Studies show that the routine use of ECMO during transplantation decreases the rate of primary graft dysfunction and many adverse outcomes including ventilator time, need for tracheostomy, renal failure, post-operative ECMO requirements, and others. As intraoperative planned ECMO is considered a safe and effective approach, with improved survival and better overall outcomes compared to both unplanned ECMO implementation and off-pump transplantation, its routine use should be taken into consideration as standard protocol.

Delirium after Cardiac Surgery-A Narrative Review

Postoperative delirium (POD) after cardiac surgery is a well-known phenomenon which carries a higher risk of morbidity and mortality. Multiple patient-specific risk factors and pathophysiologic mechanisms have been identified and therapies have been proposed to mitigate risk of delirium development postoperatively. Notably, cardiac surgery frequently involves the use of an intraoperative cardiopulmonary bypass (CPB), which may contribute to the mechanisms responsible for POD. Despite our greater understanding of these causative factors, a substantial reduction in the incidence of POD remains high among cardiac surgical patients. Multiple therapeutic interventions have been implemented intraoperatively and postoperatively, many with conflicting results. This review article will highlight the incidence and impact of POD in cardiac surgical patients. It will describe some of the primary risk factors associated with POD, as well as anesthetic management and therapies postoperatively that may help to reduce delirium.

Alterations to Kidney Physiology during Cardiopulmonary Bypass-A Narrative Review of the Literature and Practical Remarks

INTRODUCTION

According to different authors, cardiac surgery-associated acute kidney injury (CSA-AKI) incidence can be as high as 20-50%. This complication increases postoperative morbidity and mortality and impairs long-term kidney function in some patients. This review aims to summarize current knowledge regarding alterations to renal physiology during cardiopulmonary bypass (CPB) and to discuss possible nephroprotective strategies for cardiac surgeries. Relevant sections: Systemic and renal circulation, Vasoactive drugs, Fluid balance and Osmotic regulation and Inflammatory response.

CONCLUSIONS

Considering the available scientific evidence, it is concluded that adequate kidney perfusion and fluid balance are the most critical factors determining postoperative kidney function. By adequate perfusion, one should understand perfusion with proper oxygen delivery and sufficient perfusion pressure. Maintaining the fluid balance is imperative for a normal kidney filtration process, which is essential for preserving the intra- and postoperative kidney function.

FUTURE DIRECTIONS

The review of the available literature regarding kidney function during cardiac surgery revealed a need for a more holistic approach to this subject.

Cannulation Strategies in Type A Aortic Dissection: Overlooked Details and Novel Approaches

Aortic dissection type A is a life-threatening condition that frequently necessitates surgical intervention. This review focuses on central aortic cannulation, arch branch vessel (ABV) cannulation, and proximal arch cannulation as key techniques during aortic surgery. It discusses innovative solutions for addressing these challenges. The review synthesizes findings from recent studies and emphasizes the significance of meticulous planning and execution of cannulation in aortic dissection repair. This review aims to contribute to the advancement of surgical practices and the enhancement of patient outcomes in the management of type A aortic dissection (AAD) by addressing these frequently overlooked details.

Impact of Chronic Kidney Disease on Clinical Outcomes during Hospitalization and Five-Year Follow-Up after Coronary Artery Bypass Grafting

Background

Chronic kidney disease (CKD) is often associated with multiple comorbidities including diabetes mellitus, and each has its own complications and impact after cardiac surgery including coronary revascularization. The objective of this work was to study the impact of CKD on clinical outcomes after coronary artery bypass grafting (CABG) and to compare outcomes in patients with different grades of renal functions. We retrospectively reviewed all patients who underwent CABG from January 2016 to August 2020 at our tertiary care hospital using electronic medical records.

Results

The study included 410 patients with a median age of 60 years, and 28.6% of them had CKD and hospital mortality of 2.7%. About 71.4% of the patients had GFR > 60 mL/min per 1.73 m2, 18.1% had early CKD (GFR 30-60), 2.7% had late CKD (GFR < 30), and 7.8% of them had end-stage renal disease (ESRD) requiring dialysis. The CKD group had significantly more frequent hospital mortality (p = 0.04), acute cerebrovascular stroke (p = 0.03), acute kidney injury (AKI) (p < 0.001), longer ICU stay (p = 0.002), post-ICU stay (p = 0.001), and sternotomy wound debridement (p = 0.03) compared to the non-CKD group. The frequencies of new need for dialysis were 2.4% vs. 14.9% vs. 45.5% (p < 0.001) in the patients with GFR > 60 mL/min per 1.73 m2, early CKD, and late CKD, respectively. Acute cerebral stroke (OR: 10.29, 95% CI: 1.82-58.08, and p = 0.008), new need for dialysis (OR: 25.617, 95% CI: 13.78-85.47, and p < 0.001), and emergency surgery (OR: 3.1, 95% CI: 1.82-12.37, and p = 0.036) were the independent predictors of hospital mortality after CABG. The patients with CKD had an increased risk of strokes (HR: 2.14, 95% CI: 1.20-3.81, and p = 0.01) but insignificant mortality increase (HR: 1.44, 95% CI: 0.42-4.92, and p = 0.56) during follow-up.

Conclusion

The patients with CKD, especially the late grade, had worse postoperative early and late outcomes compared to non-CKD patients after CABG. Patients with dialysis-independent CKD had increased risks of needing dialysis, hospital mortality, and permanent dialysis after CABG.

Inflammatory Biomarkers and Blood Physical Property Transformations Following On-Pump Coronary Artery Bypass Graft Surgery

OBJECTIVE

This study aimed to compare the hemorheological and inflammatory changes before and after coronary artery bypass graft (CABG) surgery, as factors such as hypothermia, hemodilution, transfusion, and other variables affect blood viscosity and inflammation during the procedure.

METHODS

A total of 25 patients who underwent CABG surgery were enrolled in this study. Whole blood was collected just before the CABG (D0), 2 days after surgery (D2), and 5 days after surgery (D5). The plasma viscosity (PV) and whole blood viscosity (WBV) were measured at shear rates ranging from 0.1 to 1000 s-1 using a rheometer, and the mean values were compared. Inflammatory markers were also assessed and analyzed in relation to the hemorheological changes.

RESULTS

Compared with the baseline values, the PV significantly increased after 5 days. WBV showed a significant increase on day 2 and after 5 days. The WBV and fibrinogen were significantly correlated on day 2 and day 5 but not before surgery. Inflammatory markers such as CRP, WBC, platelets, and fibrinogen also demonstrated notable changes in relation to the hemorheological alterations.

CONCLUSIONS

This study highlights the crucial finding that hyperviscosity, characterized by elevated PV and WBV, persists for almost one week after on-pump CABG surgery. Understanding the interplay between inflammation and hemorheological properties during the postoperative period is crucial for optimizing patient care. Future research should focus on exploring the underlying mechanisms and potential therapeutic interventions to mitigate the impact of inflammation on blood viscosity and improve patient outcomes following CABG surgery.

Prevalence and Clinical Implications of Heightened Plastic Chemical Exposure in Pediatric Patients Undergoing Cardiopulmonary Bypass

Importance

Phthalate chemicals are used to manufacture disposable plastic medical products, including blood storage bags and components of cardiopulmonary bypass (CPB) circuits. During cardiac surgery, patients can be inadvertently exposed to phthalate chemicals that are released from these plastic products.

Objective

To quantify iatrogenic phthalate chemical exposure in pediatric patients undergoing cardiac surgery, and examine the link between phthalate exposure and post-operative outcomes.

Design Setting and Participants

The study cohort included 122 pediatric patients undergoing cardiac surgery at Children's National Hospital. For each patient, a single plasma sample was collected pre-operatively and two additional samples were collected post-operatively upon return from the operating room (post-operative day 0) and the morning after surgery (post-operative day 1).

Exposures

Concentrations of di(2-ethylhexyl)phthalate (DEHP) and its metabolites were quantified using ultra high-pressure liquid chromatography coupled to mass spectrometry.

Main Outcomes and Measures

Plasma concentrations of phthalates, post-operative blood gas measurements, and post-operative complications.

Results

Study subjects were subdivided into three groups, according to surgical procedure: 1) cardiac surgery not requiring CPB support, 2) cardiac surgery requiring CPB with crystalloid prime, and 3) cardiac surgery requiring CPB with red blood cells (RBCs) to prime the circuit. Phthalate metabolites were detected in all patients, and postoperative phthalate levels were highest in patients undergoing CPB with RBC-based prime. Age-matched (<1 year) CPB patients with elevated phthalate exposure were more likely to experience post-operative complications, including arrhythmias, low cardiac output syndrome, and additional post-operative interventions. RBC washing was an effective strategy to reduce DEHP levels in CPB prime.

Conclusions and Relevance

Pediatric cardiac surgery patients are exposed to phthalate chemicals from plastic medical products, and the degree of exposure increases in the context of CPB with RBC-based prime. Additional studies are warranted to measure the direct effect of phthalates on patient health outcomes and investigate mitigation strategies to reduce exposure.

Key Points

Question: Is cardiac surgery with cardiopulmonary bypass a significant source of phthalate chemical exposure in pediatric patients?Findings: In this study of 122 pediatric cardiac surgery patients, phthalate metabolites were quantified from blood samples before and after surgery. Phthalate concentrations were highest in patients undergoing cardiopulmonary bypass with red blood cell-based prime. Heightened phthalate exposure was associated with post-operative complications.Meaning: Cardiopulmonary bypass is a significant source of phthalate chemical exposure, and patients with heightened exposure may be at greater risk for postoperative cardiovascular complications.

Extracorporeal Circulation and Optic Nerve Ultrasound: A Pilot Study

Background and Objectives: Cardiopulmonary bypass (CPB) is an extracorporeal circuit that provides surgical access to an immobile and bloodless area, allowing for technical and procedural advances in cardiothoracic surgery. CBP can alter the integrity of the blood–brain barrier and cause changes in intracranial pressure (ICP) postoperatively. Optical nerve sheath diameter (ONSD) measurement is among the alternative non-invasive methods for ICP monitoring. In this study, we aimed to evaluate the optic nerve sheath diameter measurements under the guidance of ultrasonography for ICP changes during the extracorporeal circulation process. Materials and Methods: The study population included 21 patients over 18 years of age who required extracorporeal circulation. Demographic data of the patients, such as age, gender, comorbidity, American Society of Anesthesiologists (ASA) classification and reason for operation (coronary artery disease or mitral or aortic valve disease) were recorded. The ONSD was measured and evaluated before the extracorporeal circulation (first time) and at the 30th minute (second time), 60th minute (third time) and 90th minute (fourth time) of the extracorporeal circulation. Non-invasive ICP (ICP ONSD) values were calculated based on the ONSD values found. Results: The mean ONSD values measured before the extracorporeal circulation of the patients were found to be 4.13 mm (3.8–4.6) for the right eye and 4.36 mm (4.1–4.7) for the left eye. Calculated nICPONSD values of 11.0 mm Hg (1.0–21.0) for the right eye and 10.89 mm Hg (1.0–21.0) for the left eye were found. It was observed that there was a significant increase in the ONSD and nlCPONSD values recorded during the extracorporeal circulation of all patients compared to the baseline values (p < 0.005). Conclusions: During extracorporeal circulation, ultrasound-guided ONSD measurement is an easy, inexpensive and low-complication method that can be performed at the bedside during the operation to monitor ICP changes.

Renal cell carcinoma with tumor thrombus: A review of relevant anatomy and surgical techniques for the general urologist

Renal cell carcinoma (RCC) is estimated to account for 4.1% of all new cancer diagnoses and 2.4% of all cancer deaths in 2020 according to the National Cancer Institute SEER database. This will likely total 73,000 new cases and 15,000 deaths. RCC is one of the most lethal of the common cancers urologists will encounter with a 5-year relative survival of 75.2%. Renal cell carcinoma is one of a small subset of malignancies that are associated with tumor thrombus formation, which is tumor extension into a blood vessel. An estimated 4% to 10% of patients with RCC will have some degree of tumor thrombus extending into the renal vein or inferior vena cava at the time of diagnosis. Tumor thrombi change the staging of RCC and therefore are an important part of initial patient workup. It is known that such tumors are more aggressive with higher Fuhrman grades, N+ or M+ at time of surgery and have higher probability of recurrence with lower cancer-specific survival. Aggressive surgical intervention with radical nephrectomy and thrombectomy can be performed with survival benefits. Classifying the level of the tumor thrombus becomes vitally important in surgical planning as it will dictate the surgical approach. Level 0 thrombi may be amenable to simple renal vein ligation while level 4 can require thoracotomy and possible open-heart surgery with coordination of many surgical teams. Here we will review the anatomy associated with each level of tumor thrombus and attempt to construct an outline for surgical techniques that may be used. We aim to give a concise overview so that general urologists may use it to understand these potentially complicated cases.

Effects of early mobilization on pulmonary parameters and complications post coronary artery bypass graft surgery

This study compared the effects of a four-phase and a three-phase early mobilization protocol on respiratory parameters and complications in patients following coronary artery bypass graft surgery. This is a three-arm, parallel-group, randomized controlled clinical trial with 120 candidates for coronary artery bypass graft surgery. Participants were randomly allocated to three groups: four-phase early mobilization protocol, three-phase early mobilization protocol, and control. Arterial blood gases, oxygen saturation, and incidence of pulmonary complications were compared among the groups. Mean arterial blood gases and oxygen saturation improved significantly over time in both four-phase early mobilization protocol and three-phase early mobilization protocol groups compared to control (p < 0.05). There were observed trends for greater improvements in the study outcomes with three-phase early mobilization protocol than four-phase early mobilization protocol; however, did not reach statistically significant levels. The incidence of pulmonary complications was significantly in both intervention groups compared to control (odds ratio: 0.48, 95 % CI 0.007-0.537; p < 0.001). Both four-phase early mobilization and the three-phase early mobilization protocols improved respiratory parameters and reduced pulmonary complications. Statistically insignificant trends were found trends in the three-phase early mobilization protocol, focusing on chest physiotherapy and breathing exercises.

Metalloproteinases in Cardiac Surgery: A Systematic Review

The role of matrix metalloproteinases (MMPs) in routine cardiac operations including cardiopulmonary bypass (CPB) is still poorly explored. The purpose of this systematic review was to thoroughly summarize and discuss the existing knowledge of the MMP profile in cardiac surgery. All studies meeting the inclusion criteria (i.e., those reporting detailed data about MMP release during and after CPB) were selected after screening the literature published between July 1975 and August 2022. Fifteen trials that enrolled a total of 431 participants were included. MMP levels were found to be significantly correlated with CPB in all included studies. The gelatinases MMP-2 and MMP-9 were highly released in cardiac surgery with CPB. MMP-9 levels were found to be increased after CPB start and during the duration of CPB. Particularly, it is overexpressed both in the myocardial tissue and circulating in the bloodstream. Also, MMP-2 levels increased after CPB both in plasma and in myocardial tissue. MMP-7, MMP-8, and MMP-13 levels increased after CPB start and remained elevated up to 6 h later. Increased levels of MMPs were associated with adverse post-operative outcomes. Conversely, TIMP-1 decreased with CPB. Mechanical and pharmacological strategies were applied in two studies to analyze their effect on the inflammatory response to cardiac surgery and CPB and on postoperative outcomes. New targeted MMP inhibitor therapies could protect against systemic inflammatory response syndrome after CPB and should be the subject of future large prospective multicenter randomized clinical trials.

Inhibition of mitochondrial reactive oxygen species improves coronary endothelial function after cardioplegic hypoxia/reoxygenation

OBJECTIVE

Cardioplegic ischemia-reperfusion and diabetes mellitus are correlated with coronary endothelial dysfunction and inactivation of small conductance calcium-activated potassium channels. Increased reactive oxidative species, such as mitochondrial reactive oxidative species, may contribute to oxidative injury. Thus, we hypothesized that inhibition of mitochondrial reactive oxidative species may protect coronary small conductance calcium-activated potassium channels and endothelial function against cardioplegic ischemia-reperfusion-induced injury.

METHODS

Small coronary arteries and endothelial cells from the hearts of mice with and without diabetes mellitus were isolated and examined by using a cardioplegic hypoxia and reoxygenation model to determine whether the mitochondria-targeted antioxidant Mito-Tempo could protect against coronary endothelial and small conductance calcium-activated potassium channel dysfunction. The microvessels or mouse heart endothelial cells were treated with or without Mito-Tempo (0-10 μM) 5 minutes before and during cardioplegic hypoxia and reoxygenation. Microvascular function was assessed in vitro by vessel myography. K+ currents of mouse heart endothelial cells were measured by whole-cell patch clamp. The levels of intracellular cytosolic free calcium (Ca2+) concentration, mitochondrial reactive oxidative species, and small conductance calcium-activated potassium protein expression of mouse heart endothelial cells were measured by Rhod-2 fluorescence staining, MitoSox, and Western blotting, respectively.

RESULTS

Cardioplegic hypoxia and reoxygenation significantly attenuated endothelial small conductance calcium-activated potassium channel activity, caused calcium overload, and increased mitochondrial reactive oxidative species of mouse heart endothelial cells in both the nondiabetic and diabetes mellitus groups. In addition, treating mouse heart endothelial cells with Mito-Tempo (10 μM) reduced cardioplegic hypoxia and reoxygenation-induced Ca2+ and mitochondrial reactive oxidative species overload in both the nondiabetic and diabetes mellitus groups, respectively (P < .05). Treatment with Mito-Tempo (10 μM) significantly enhanced coronary relaxation responses to adenosine 5'-diphosphate and NS309 (P < .05), and endothelial small conductance calcium-activated potassium channel currents in both the nondiabetic and diabetes mellitus groups (P < .05).

CONCLUSIONS

Administration of Mito-Tempo improves endothelial function and small conductance calcium-activated potassium channel activity, which may contribute to its enhancement of endothelium-dependent vasorelaxation after cardioplegic hypoxia and reoxygenation.

Analysis of the risk factors for severe lung injury after radical surgery for tetralogy of fallot

Objective

This study aimed to determine the risk factors for severe lung injury (SLI) (partial pressure of oxygen/fraction of inspired oxygen <150) after radical surgery for tetralogy of Fallot with pulmonary stenosis (TOF/PS) in children.

Method

A retrospective analysis was conducted including a total of 287 children with TOF/PS aged below 10 years (including 166 males) who had undergone radical surgery at the Center of Pediatric Heart Disease of the Beijing Anzhen Hospital (China) from 2018 to 2020.

Results

A total of 83 cases (28.9%) had SLI after surgery. Univariate analysis showed that age, weight, pulmonary artery index (PAI), cardiopulmonary bypass (CPB) time, and polymorphonuclear leukocyte (PMN) percentage on the first day after surgery were risk factors for postoperative SLI. Multivariate logistic regression analysis showed that PAI, PMN percentage on the first day postoperatively, and CPB time were independent risk factors for SLI after surgery. The prediction model was established as follows: Logit(P) = 2.236 + 0.009*CPB-0.008*PAI-0.035*PMN, area under the curve (AUC) = 0.683, P < 0.001, sensitivity 65.8%, and specificity 68.6%. Following surgery, static lung compliance was significantly lower in the SLI group compared with the routine group. Complication rates and mortality were significantly higher in the SLI than in the routine group. Ventilator support times, the length of intensive care unit stays, and the total lengths of hospital stay were significantly longer in the SLI than in the routine group.

Conclusion

The occurrence of SLI following radical surgery for TOF in children significantly affected postoperative recovery, and PAI, PMN percentage on the first day postoperatively, and CPB time were independent risk factors for SLI.

High-Dose Hydroxocobalamin for Refractory Vasoplegia Post Cardiac Surgery

Administration of high-dose hydroxocobalamin, or vitamin B12, is an emerging, targeted rescue therapy for the treatment of refractory vasoplegic shock. This is an uncommon but potentially life-threatening complication following cardiac surgery and carries a poor prognosis, particularly when patients fail to respond to first-line therapy with catecholamine vasopressors. This study describes our experience in treating refractory vasodilatory shock following cardiac surgery with high-dose hydroxocobalamin. Administration of hydroxocobalamin in seven patients was associated with an improvement in mean arterial blood pressure or reduction in vasopressor requirements, which were both immediate and sustained throughout our observational period. No deaths or adverse effects attributable to hydroxocobalamin administration occurred in our cohort. Our observations show that high-dose hydroxocobalamin is a safe and effective rescue therapy in refractory vasoplegic shock post cardiopulmonary bypass (CPB).

κ-Opioid Receptor Agonist U50448H Protects Against Acute Lung Injury in Rats with Cardiopulmonary Bypass via the CAP-NLRP3 Signaling Pathway

Objective. Acute lung injury (ALI) is one of the common and severe complications of cardiopulmonary bypass (CPB), which is the primary cause of death in intensive care units. Nevertheless, there is a lack of effective treatment for ALI secondary to CPB. κ-Opioid receptor (KOR) agonists have been demonstrated to improve lung function after pulmonary hypertension. However, its protective role has been barely reported in CPB-induced acute respiratory distress syndrome (ARDS). Therefore, this research focused on the protective effect of a KOR agonist U50448H on ARDS and investigated its potential relationship with the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome. Method. Forty-five rats were randomly allocated into Sham, CPB, and U50448 groups (n = 15 rats/group). After a CPB model was successfully established in rats, CPB rats were treated with the KOR agonist U50448H. The values of extravascular lung water (EVLW), alveolar-arterial oxygen tension difference (AaDO2), and respiratory index (RI) were examined, and the lung wet/dry (W/D) weight ratio was also calculated. Western blot (WB) was utilized to measure the expression of MMP-9, GSDMD-C, GSDMD-N, NLRP3, ASC, pro-Caspase-1, pro-IL-1β, and α7-nAChR. The immunofluorescence assay was performed for examining the expression of ROS, F480, iNOS, CD206, and α7-nAChR. Cell apoptosis was detected by the TUNEL assay. ELISA was used to test the level of LPS in serum and the level of MDA, GSH, SOD, TNF-α, IL-4, IL-6, IL-18, and IL-1β in lung tissues. Results. It was observed that the administration of U50448H significantly reduced EVLW values and LPS levels in the lung of rats. Meanwhile, U50448H increased AaDO2 values while decreasing RI values. Moreover, the administration of U50448H alleviated the pathological damage caused by ALI secondary to CPB. U50448H repressed ROS release and oxidative stress responses, as well as lowered LPS levels in plasma and MMP-9 expression in the lung of CPB rats. Furthermore, U50448H facilitated the shift of macrophage phenotype to M2. In addition, U50448H decreased the activity of the CAP-NLRP3 inflammasome and suppressed pyroptosis in pulmonary cells. Conclusion. The KOR agonist U50448H improved lung function and relieved lung injury in CPB rats, accompanied by diminished ROS and MMP-9 levels in lung tissues, promoted macrophage polarization from M1 to M2, and reduced NLRP3 inflammasome activities. These results indicated U50448H as a promising drug for the treatment of ALI secondary to CPB.

Sellke F, Feng J. Potassium and Cardiac Surgery

Potassium homeostasis affects cardiac rhythm and contractility, along with vascular reactivity and vascular smooth muscle proliferation. This chapter will focus on potassium dynamics during and after cardiac surgery involving cardioplegic arrest and cardiopulmonary bypass (CPB). Hyperkalemic, hypothermic solutions are frequently used to induce cardioplegic arrest and protect the heart during cardiac surgery involving CPB. Common consequences of hyperkalemic cardioplegic arrest and reperfusion include microvascular dysfunction involving several organ systems and myocardial dysfunction. Immediately after CPB, blood potassium levels often drop precipitously due to a variety of factors, including CPB -induced electrolyte depletion and frequent, long-term administration of insulin during and after surgery. Meanwhile, some patients with pre-existing kidney dysfunction may experience postoperative hyperkalemia following cardioplegia. Any degree of postoperative hyper/hypokalemia significantly elevates the risk of cardiac arrythmias and subsequent myocardial failure. Therefore, proper management of blood potassium levels during and after cardioplegia/CPB is crucial for optimizing patient outcomes following cardiac surgery.

A comparative study on the results of beating and arrested heart isolated tricuspid valve surgery: A cross-sectional study

Background and Aims

The isolated tricuspid valve surgery is performed using beating or arrested heart surgery. The present study aimed to evaluate and compare the results of patients who underwent isolated tricuspid valve surgery using the beating and arrested heart techniques.

Methods

In this retrospective observational study, all patients undergoing isolated tricuspid valve surgery between 2011 and 2018 were included. The patient's demographic information, echocardiographic, surgery, and hospitalization results were collected, and the EuroSCORE was calculated from the patient's medical records.

Results

Fifty-three patients were included in the study of which 21 (39.63%) and 32 (60.37%) underwent a beating heart and arrested heart surgeries, respectively. There were no significant differences between the two studied groups in the echocardiographic results before and after the surgery, total hospitalization days (p = 0.56), and the mortality in the first 30 days after the surgery (p = 0.152). However, the duration of surgery (p < 0.001), EuroSCORE (p = 0.005), and patients who underwent lateral thoracotomy (p = 0.007) were notably lower in the arrested heart than in the beating heart group. In contrast, the duration of cardiopulmonary bypass and hospitalization in an intensive care unit after the surgery was remarkably lower in the beating heart than in the arrested heart group (p < 0.001 for both cases).

Conclusion

Although there were some significant differences between the two kinds of surgery techniques, it seems superficial that made a particular decision to consider each method's superiority. Therefore, further studies with larger populations and meta-analyses are required to recommend the preferred method for the surgeons certainly.

Patching an aortic tear using the side-arm and surrounding skirt of a physician-modified ascending aortic graft

BACKGROUND AND AIM OF STUDY

Aortic complications during cannulation must be managed urgently and often require hypothermic circulatory arrest. We report a unique management strategy to repair an aortic tear without dissection by modifying a Dacron ascending aortic graft with side-arm.

CASE PRESENTATION

A 32-year-old female patient undergoing reoperative cardiac surgery suffered an unexpected aortic tear during cannulation for cardiopulmonary bypass. The tear was repaired by utilizing a physician-modified ascending aortic graft with side-arm, in which the surrounding skirt of the side-arm was cut from the circumferential graft to patch the defect. The patient was rewarmed with the side-arm serving as arterial inflow for the bypass circuit, and the remainder of the operation proceeded without complication.

CONCLUSION

This type of aortic repair for aortic tears without dissection can offer the patient the benefit of avoiding multiple aortotomies in a weakened aorta, reducing circulatory arrest time, and re-establishing a central cannulation strategy for cardiopulmonary bypass.

Neuroprotection in aortic arch surgery: untold flaws and future directions

The current paradigm of brain protection in aortic surgery falls short of delivering good outcomes with minimal complications. A renewed understanding of neuroprotective methods and biomarkers to predict brain injury and aortic disease are crucial towards the development of more effective clinical management strategies. A review of current literature was carried out to identify current flaws in our approach to neuroprotection in aortic surgery. Emerging evidence surrounding neuroprotective strategies, biomarkers for brain injury, and biomarkers for predicting aortic disease are evaluated in terms of their impact for future therapeutic approaches. Current literature suggests that the prevailing methods of neuroprotection need renewal. Clinical outcomes associated with deep hypothermic circulatory arrest remain varied. Branch-first and endovascular approaches to aortic repair are particularly promising alternatives. The use of biomarkers to identify and manage brain injury, as well as to diagnose aortic disease in the nonacute and acute settings, would further help to improve our overall paradigm of neuroprotection in aortic surgery. Though much prospective research is still required, the outlook for neuroprotection in aortic surgery is promising. Adopting alternative surgical techniques and exploiting predictive novel biomarkers will help us to gradually eliminate the risk of brain damage in aortic surgery.

Relationship between predisposing and facilitating factors: Does it influence the risk of developing peri-operative pressure injuries?

This study examined the relationship between the personal predisposing factors of patients and the severity of pressure injuries (PIs) developed during surgery. This retrospective cohort study collected 439 cases of peri-operative PIs. Using binary logistic regression to identify the variables associated with PI severity, the effects of interactions between associated variables were then tested. The results of this study revealed that among the personal predisposing factors, only higher patient age (P = .001) and higher body mass index (P < .001) posed a greater risk of stage 2 PIs or higher. Among the surgery-related facilitating factors, only patients who were placed in the prone position during surgery and patients who lost ≥1000 mL of blood during surgery were at greater risk of stage 2 PIs or higher, compared, respectively, to those placed in the supine position and those who lost ≤100 mL of blood. Furthermore, the amount of blood lost during surgery moderated the influence of age on PI severity. For elderly patients who are expected to lose a large blood volume during surgery or lose an immeasurable amount of blood due to the use of cardiopulmonary bypass, taking more precautionary measures to prevent PIs is recommended.

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.

Complement activation during cardiopulmonary bypass and association with clinical outcomes

In this prospective, single-centre observational study of 30 patients undergoing cardiopulmonary bypass (CPB), the effect of unfractionated heparin (UFH), CPB surgery and protamine sulphate on complement and on post-operative blood loss were assessed. Although C3 and C4 levels decreased significantly immediately following the administration of UFH, C3a, C5a, Bb fragment and SC5b-9 remained unchanged. During CPB, C3 and C4 continued to fall whilst both alternative and classical pathways activation markers, Bb, C3a, C5a and SC5b-9 increased significantly. Protamine sulphate had no effect on classical pathway components or activation markers but decreased alternative pathway activation marker Bb. Over the 12-24 h post-surgery, both classical and alternative pathway activation markers returned to baseline, whilst C3 and C4 levels increased significantly but not to baseline values. Total drain volume 24 h after the surgery showed a moderate inverse correlation with post-protamine C3 (r = -0.46, p = 0.01) and C4 (r = -0.57, p = 0.0009) levels, whilst a moderate positive correlation was observed with post-protamine C3a (r = 0.46, p = 0.009), C5a (r = 0.37, p = 0.04) and SC5b-9 (r = 0.56, p = 0.001) levels but not with Bb fragment (r = 0.25, p = 0.17). Thus, inhibition of complement activation may be a therapeutic intervention to reduce post-operative blood in patients undergoing CPB.

Clinical factors associated with arrhythmia and short-term prognosis following mitral valve repair: a retrospective cohort study

BACKGROUND

Postoperative arrhythmia (POA) is one of the common and serious postoperative complications. This retrospective study was conducted to investigate the clinical factors associated with POA and its short-term prognosis following mitral valve repair.

METHODS

A total of 618 patients receiving mitral valve repair between January 2015 and November 2020 in our hospital were included in this retrospective study, including 318 males and 300 females and aged 53.9±9.3 years. The patients were grouped into arrhythmia and non-arrhythmia groups and investigated for risk factors associated with the prognosis of POA using multivariate logistic regression based on their clinical data.

RESULTS

POA was observed in 314 (50.8%) patients and atrial fibrillation (AF) was the most frequent (43.3%) type of POA. Compared with non-arrhythmia patients, arrhythmia patients had significantly longer time to use vasoactive drug use, longer intensive care unit (ICU) stay and longer hospital stay. In addition, the incidence of postoperative heart failure was significantly higher (P<0.05). Logistic regression analysis showed that preoperative arrhythmia [odds ratio (OR) =9.17; 95% confident interval (CI): 4.49-18.10], postoperative pain (OR =4.70; 95% CI: 1.55-6.12) and postoperative hypoxemia (OR =3.25; 95% CI: 1.04-6.28) were independently associated with POA.

CONCLUSIONS

This study demonstrates that the incidence of arrhythmia is relatively high after mitral valve repair and is associated with preoperative arrhythmia, postoperative pain and postoperative hypoxemia.

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.