The use of RemoweLL oxygenator-integrated device in the prevention of the complications related to aortic valve surgery in the elderly patient: Preliminary results

Background The effects of fat microembolization due to cardiopulmonary bypass are well known in cardiac surgery. Our aim is to evaluate the use of the RemoweLL device (Eurosets, Medolla, Italy) during elective aortic valve replacement in elderly patients (>70 years old) to rate its biochemical and clinical effects. The RemoweLL device is an oxygenator-integrated reservoir which combines two strategies for fat emboli and leucocytes removal: filtration and supernatant elimination. Methods Forty-four elderly patients were enrolled and assigned randomly to a Group A (standard device) and a Group B (RemoweLL). Biochemical effects were evaluated by blood samples, which were tested for white blood cells, neutrophils, protein SP-100 and interleukin 6 besides standard lab tests. Our clinical endpoints were any type of neurological, cardiac, respiratory, gastrointestinal or renal complications, and length of stay in the intensive care unit. Statistical analysis was carried out with chi square test for non-parametric data; t test and analysis of variance for repeated measures were used for parametric data. Results Group B showed lower levels of white blood cells, neutrophils, interleukin 6 and protein SP-100 immediately and 24 hours after the operation. Group B also showed a lower amount of neurocognitive type II dysfunction even if the length of stay in the ICU did not change. Conclusions The RemoweLL system is safe and effective in reducing inflammatory response to cardiopulmonary bypass and it could be a useful tool in minimizing negative effects of cardiopulmonary bypass; however, it does not seem to have any effect on elderly patients' hospital stay.

A Novel Macroscale Acoustic Device for Blood Filtration

Retransfusion of a patient's own shed blood during cardiac surgery is attractive since it reduces the need for allogeneic transfusion, minimizes cost, and decreases transfusion related morbidity. Evidence suggests that lipid micro-emboli associated with the retransfusion of the shed blood are the predominant causes of the neurocognitive disorders. We have developed a novel acoustophoretic filtration system that can remove lipids from blood at clinically relevant flow rates. Unlike other acoustophoretic separation systems, this ultrasound technology works at the macroscale, and is therefore able to process larger flow rates than typical micro-electromechanical system (MEMS) scale acoustophoretic separation devices. In this work, we have first demonstrated the systematic design of the acoustic device and its optimization, followed by examining the feasibility of the device to filter lipids from the system. Then, we demonstrate the effects of the acoustic waves on the shed blood; examining hemolysis using both haptoglobin formation and lactate dehydrogenase release, as well as the potential of platelet aggregation or inflammatory cascade activation. Finally, in a porcine surgical model, we determined the potential viability of acoustic trapping as a blood filtration technology, as the animal responded to redelivered blood by increasing both systemic and mean arterial blood pressure.

Leukocyte filtration of the cardiotomy suction. Does it affect systemic leukocyte activation or pulmonary function?

Background:

Cardiopulmonary bypass is thought to propagate a global systemic response through contact with the non-physiological surfaces of the extracorporeal circuit, leading to the stimulation of leukocytes, their adherence to endothelial cells and the release of cytotoxic molecules. This, in turn, has been shown to accelerate pulmonary injury. This study tested a new leukocyte-filtration system (RemoweLL) against a conventional system with no leukocyte-depleting capacity to determine the efficacy of the filtration system and its effects on pulmonary function.

Methods:

Thirty patients underwent coronary artery bypass graft surgery using either the RemoweLL filtration system (15 patients) or a conventional cardiopulmonary bypass circuit (15 patients). Data were collected on the total number of leukocytes, their differentiation and activation, using the leukocyte adhesion integrin CD11b as a surrogate marker. Pulmonary function was assessed using the Alveolar-arterial Oxygenation Index (AaOI) and patients were categorized using the Berlin definition of acute respiratory distress syndrome (ARDS).

Results:

Both groups showed significant increases in leukocyte numbers during CPB (p<0.001), with no differences noted between the groups. CD11b showed a significant increase in both groups, with peak activation occurring at the end of CPB, but no difference between the groups (p=0.8). There was a trend towards lower AaOI increases in the filtration group, but this did not reach significance (p=0.075) and there was no difference in ARDS definitions (p=0.33).

Conclusions:

Leukocyte filtration of cardiotomy suction did not influence total leukocyte counts or activation as measured by CD11b upregulation. Furthermore, no evidence could be found to suggest improved pulmonary function.

Efficacy of the RemoweLL cardiotomy reservoir for fat and leucocyte removal from shed mediastinal blood: a randomized controlled trial

Introduction:

Re-transfusion of lipid particles and activated leucocytes with shed mediastinal blood (SMB) can aggravate cardiopulmonary bypass-associated inflammation and increase the embolic load. This study evaluated the fat and leucocyte removal capacity of the RemoweLL cardiotomy reservoir.

Methods:

Forty-five patients undergoing elective on-pump cardiac surgery were randomly allocated to filtration of SMB using the RemoweLL or the Admiral cardiotomy reservoir. The primary outcome was a drop in leucocytes and lipid particles obtained with the two filters. The effect of the filters on other blood cells and inflammatory mediators, such as myeloperoxidase (MPO), was also assessed.

Results:

The RemoweLL cardiotomy filter removed 16.5% of the leucocytes (p<0.001) while no significant removal of leucocytes was observed with the Admiral (p=0.48). The percentage reductions in lipid particles were similar in the two groups (26% vs 23%, p=0.2). Both filters similarly affected the level of MPO (p=0.71).

Conclusion:

The RemoweLL filter more effectively removed leucocytes from SMB than the Admiral. It offered no advantage in terms of lipid particle clearance.

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.