Mastering the Best Practices: A Comprehensive Look at the European Guidelines for Cardiopulmonary Bypass in Adult Cardiac Surgery

The successful outcome of a cardiac surgery procedure is significantly dependent on the management of cardiopulmonary bypass (CPB). Even if a cardiac operation is technically well-conducted, a patient may suffer CPB-related complications that could result in severe comorbidities, reduced quality of life, or even death. However, the role of clinical perfusionists in perioperative patient care, which is critical, is often overlooked. Therefore, the European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Cardiothoracic Anaesthesiology (EACTA), and the European Board of Cardiovascular Perfusion (EBCP) have agreed to develop joint clinical practice guidelines (CPGs) for CPB due to its significant impact on patient care and significant variations in practice patterns between countries. The European guidelines, based on the EACTS standardized framework for the development of CPGs, cover the entire spectrum of CPB management in adult cardiac surgery. This includes training and education of clinical perfusionists, machine hardware, disposables, preparation for initiation of CPB, a complete set of procedures during CPB to help maintain end-organ function and anticoagulation, weaning from CPB, and the gaps in evidence and future research directions. This comprehensive coverage ensures that all aspects of CPB management are addressed, providing clinicians with a standardized approach to CPB management based on the latest evidence and best practices. To ensure better integration of these evidence-based recommendations into daily practice, this review aims to provide a general understanding of guideline development and an overview of essential treatment recommendations for CPB management.

Cardioprotective potential of annexin-A1 mimetics in myocardial infarction

Myocardial infarction (MI) and its resultant heart failure remains a major cause of death in the world. The current treatments for patients with MI are revascularization with thrombolytic agents or interventional procedures. These treatments have focused on restoring blood flow to the ischemic tissue to prevent tissue necrosis and preserve organ function. The restoration of blood flow after a period of ischemia, however, may elicit further myocardial damage, called reperfusion injury. Pharmacological interventions, such as antioxidant and Ca(2+) channel blockers, have shown premises in experimental settings; however, clinical studies have shown limited success. Thus, there is a need for the development of novel therapies to treat reperfusion injury. The therapeutic potential of glucocorticoid-regulated anti-inflammatory mediator annexin-A1 (ANX-A1) has recently been recognized in a range of systemic inflammatory disorders. ANX-A1 binds to and activates the family of formyl peptide receptors (G protein-coupled receptor family) to inhibit neutrophil activation, migration and infiltration. Until recently, studies on the cardioprotective actions of ANX-A1 and its peptide mimetics (Ac2-26, CGEN-855A) have largely focused on its anti-inflammatory effects as a mechanism of preserving myocardial viability following I-R injury. Our laboratory provided the first evidence of the direct protective action of ANX-A1 on myocardium, independent of inflammatory cells in vitro. We now review the potential for ANX-A1 based therapeutics to be seen as a "triple shield" therapy against myocardial I-R injury, limiting neutrophil infiltration and preserving both cardiomyocyte viability and contractile function. This novel therapy may thus represent a valuable clinical approach to improve outcome after MI.

Long-term leukocyte filtration should be avoided during extracorporeal circulation

Filtration during extracorporeal circulation (ECC) not only removes but also activates leukocytes; therefore, long-term leukocyte filtration may cause adverse effects. In the present study, we tested this hypothesis by priming ECC with 300 mL of canine blood and examining filtration effects in 3 groups (n = 6 each) during 60 min ECC. In the control group (Group C) blood was filtrated with an arterial filter for 60 min; in long-term (Group L) and short-term (Group S) groups, blood was filtrated with a leukocyte filter for 60 and 5 min. We found that about 90% of leukocytes were removed after 5 min of filtration in both Groups L and S. Although leukocyte count continued to reduce, mean fluorescent intensities of CD11/CD18, free hemoglobin, and neutrophil elastase increased in Group L and were higher than those in Groups C and S at 60 min. Leukocyte rupture, cytoplasmic leakage, and circulating naked nuclei were also found in Group L. The data support our hypothesis that long-term filtration can induce inflammation and lead to leukocyte destruction.

The effect of systemic arterial-line leukocyte filtration on the outcome of adult patients undergoing cardiac surgery

BACKGROUND

It is known that cardiopulmonary bypass causes an inflammatory reaction with associated morbidity and mortality. Several anti-inflammatory strategies have been implemented to reduce this response, including leukocyte removal from the circulation using specialized filters.

OBJECTIVES

The aim of this randomized clinical study was to assess the impact of arterial-line systemic leukocyte filtration on the postoperative outcome of adult patients undergoing elective cardiac surgery.

PATIENTS AND METHODS

114 patients undergoing CABG or valve replacement in Baqiyatallah hospital, Tehran, Iran from May to August 2011 were randomly assigned to two groups: with and without leukocyte filtration and their outcomes were compared.

RESULTS

The postoperative intubation time was significantly shorter in patients with leukocyte filters (0.014). There was no significant difference between two groups regarding other outcome relatedvariables.

CONCLUSIONS

Systemic arterial leukocyte filtration reduces the intubation time but has no other beneficial effect on the outcome of patients undergoing CABG or valve surgery.

Leukodepletion for patients undergoing heart valve surgery

BACKGROUND

There is some evidence for the benefits of leukodepletion in patients undergoing coronary artery surgery. Its effectiveness in higher risk patients, such as those undergoing heart valve surgery, particularly in terms of overall clinical outcomes, is currently unclear.

OBJECTIVES

To assess the beneficial and harmful effects of leukodepletion on clinical, patient-reported and economic outcomes in patients undergoing heart valve surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 3 of 12) in The Cochrane Library, the NHS Economic Evaluations Database (1960 to April 2013), MEDLINE Ovid (1946 to April week 2 2013), EMBASE Ovid (1947 to Week 15 2013), CINAHL (1982 to April 2013) and Web of Science (1970 to 17 April 2013) on 19 April 2013. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), the US National Institutes of Health (NIH) clinical trials database and the International Standard Randomised Controlled Trial Number Register (ISRCTN) in April 2013 for ongoing studies. No language or time period restrictions were applied. We examined the reference lists of all included randomised controlled trials and contacted authors of identified trials. We searched the 'grey' literature at OpenGrey and handsearched relevant conference proceedings.

SELECTION CRITERIA

Randomised controlled trials comparing a leukocyte-depleting arterial line filter with a standard arterial line filter, on the arterial outflow of the heart-lung bypass circuit, in elective patients undergoing heart valve surgery.

DATA COLLECTION AND ANALYSIS

Data were collected on the study characteristics, three primary outcomes (1. post-operative in-hospital all-cause mortality within three months, 2. post-operative all-cause mortality excluding inpatient mortality < 30 days, 3. length of stay in hospital, 4. adverse events and serious adverse events) and seven secondary outcomes (1. tubular or glomerular kidney injury, 2. validated health-related quality of life scales, 3. validated renal injury scales, 4. use of continuous veno-venous haemo-filtration, 5. length of stay in intensive care, 6. costs of care). Data were extracted by one author and verified by a second author. Insufficient data were available to perform a meta-analysis or sensitivity analysis.

MAIN RESULTS

Eight studies were eligible for inclusion in the review but data on prespecified review outcomes were available from only one, modestly powered (24 participants) study (Hurst 1997). There were no differences between a leuko-depleting versus standard filter in length of stay in the intensive care unit (ICU) (mean difference (MD) 0.80 days; 95% confidence interval (CI) -0.24 to 1.84) or length of hospital stay (MD 0.20 days; 95% CI -1.78 to 2.18).

AUTHORS' CONCLUSIONS

There are currently insufficient good quality trials with valve surgery patients to inform recommendations for changes in clinical practice. A future National Institute for Health Research (NIHR)-funded feasibility study (recruiting mid-year 2013) comparing leukodepletion with a standard arterial line filter in patients undergoing elective heart valve surgery (the ROLO trial) will be the largest study to date and will make a significant contribution to future updates of this review.

Does leukocyte-depleted blood cardioplegia reduce myocardial reperfusion injury in cardiac surgery? A systematic review and meta-analysis

Blood cardioplegia in cardiac surgery contains leukocytes, which causes the inflammatory reaction and promotes myocardial reperfusion injury. The removal of leukocytes from the cardioplegia line, using specialized filters, has been proposed as one of the effective methods in attenuating the inflammatory response. We performed a two-level search to identify randomized, controlled trials concerning the effects of leukocyte-depleted blood cardioplegia on myocardial reperfusion injury. Sixteen studies, comprising 738 patients, met the selection criteria. There are significant reductions in creatinine kinase isoenzyme MB (CK-MB) during 4-8h postoperatively (SMD - 0.577; 95% CI -0.795 to -0.358; p=0.000), CK-MB peak (SMD - 0.713; 95% CI -1.027 to -0.400; p=0.000), troponin in the period of 4-8h postoperatively (SMD - 0.502; 95% CI -0.935 to -0.069; p=0.023), troponin peak (SMD - 0.826; 95% CI -1.373 to -0.279; p=0.003) and inotropic support (RR, 0.500; 95% CI 0.269 to 0.931; p=0.029). Leukocyte-depleted blood cardioplegia may reduce myocardial reperfusion injury in the early postoperative period, but there has been no evidence to support the clinically significant difference. Larger and more precise randomized control trials are needed to further elucidate the cardioprotective effects of cardioplegia leukofiltration.

Troubleshooting the rat model of cardiopulmonary bypass: effects of avoiding blood transfusion on long-term survival, inflammation and organ damage

INTRODUCTION

Rat models of cardiopulmonary bypass (CPB) have been used to examine the mechanisms of associated organ damage and to test intervention strategies. However, these models only partly mimic the clinical situation, because of the use of blood transfusion and arterial inflow via the tail artery. Thus a model using arterial inflow in the aorta and a miniaturized CPB circuit without need of transfusion was validated by examining intra-procedure characteristics, mortality and the effects of CPB on biomarkers of inflammation and cerebral injury during 5days follow-up.

METHODS

Male Wistar rats (n=95) were anesthetized with isoflurane (2.5%) and fentanyl/midazolam during CPB. Animals were assigned to Control (n=6), Sham (n=40) or normothermic CPB (n=49) groups. Both Sham and CPB were cannulated in the aorta via the left carotid artery and in the right common jugular vein for access into the right heart. Extracorporeal circulation (ECC) was instituted for 60min only in CPB at a flow rate of 120mLkg(-1)min(-1) employing a CPB circuit of 15ml primed with 6% hydroxyethyl starch 60mgml(-1) solution. Rats were sacrificed at either 1h or 1, 2 or 5days after Sham or weaning from CPB. Plasma IL-6 and s100Beta levels were measured and blood cell counts were performed.

RESULTS

Mortality in CPB animals (3 out of 49) and Sham (4 out of 40) did not differ (chi-square=0.46, dF=1, P>0.5). Compared to baseline (1.87±0.46∗10^9cells/L), Sham procedure (cannulation and anesthesia) significantly increased blood neutrophil count at the end of the period matching ECC (6.34±2.36∗10^9cells/L, P<0.05). CPB induced neutrophilia which persisted during 24h recovery. Also, CPB caused a rapid and prominent increase in plasma IL-6 from the first hour of the postoperative period (~1200pg/ml) with continuation (50-90pg/ml) up to 5th day of recovery. S100Beta levels were above detection level only in 3 out of 42 samples from CPB animals.

DISCUSSION

Our rat model of CPB without homologous blood transfusion produces a reproducible and reliable systemic inflammatory response, with low mortality rates on long term follow up. The model more closely mimics the human situation in respect to arterial inflow site and avoidance of blood transfusion. Thus, our CPB model is suitable to study its influence on systemic inflammation, ischemia-reperfusion injury, microcirculation and vascular dysfunction in vivo, and to evaluate potential therapeutic interventions.