Miniaturized Cardiopulmonary Bypass Research Articles

Effect of different coronary artery revascularization procedures on cognition: A systematic review

Coronary revascularization interventions have been associated with post-intervention cognitive decline. Hence, this systematic review aims to compare the long-term effects of different coronary revascularization interventions on cognition. The Cochrane Library and MEDLINE databases were searched for articles published between January 2009 and January 2023. Articles on clinical trials and cohort studies that compared at least two different interventions with a minimum three months follow up were included to evaluate the consequences of different intervention techniques on cognition. Each selected study was evaluated using a revised tool to assess the risk of bias in randomized trials (RoB 2), and Risk of Bias In Non-Randomized Studies - of Interventions(ROBINS-1) was used for evaluating non-randomized studies. Five eligible studies, with four different comparisons, were included. Out of these studies, three RCTs and two cohort studies were included A participants gone through different procedures; on-pump and off-pump coronary artery bypass grafting (CABG), Percutaneous coronary intervention (PCI conventional cardiopulmonary bypass (CCPB), the miniaturized cardiopulmonary bypass (MCPB) and endoscopic coronary artery bypass grafting (Endo-CABG). These comparisons showed that different interventions have different effects on cognition; however, there is no solid evidence of correlations between them. Thus, the results of this review suggest that there should be greater focus on comparing interventions and that a reasonable follow-up duration should be set to avoid the influence of confounders. There is also a need to determine the effect of long-term cognitive decline while reducing interference by other variables.

Miniaturized versus conventional cardiopulmonary bypass and acute kidney injury after cardiac surgery.

Acute kidney injury (AKI) is a serious complication after coronary artery bypass grafting (CABG). There are conflicting reports whether a miniaturized cardiopulmonary bypass (MCPB) system is associated with a lower AKI incidence compared with conventional cardiopulmonary bypass (CCPB). It is unknown if AKI risk factors differ between the two groups. We assessed if MCPB decreases AKI after CABG and compared the risk factors between both groups. Sixty-eight Asian patients presenting for elective CABG at a tertiary heart centre were enrolled. They were randomly assigned to MCPB (n=34) or CCPB group (n=34) and followed up in a single-blinded, prospective, randomized, controlled trial. The primary outcome was Acute Kidney Injury Network stage 1 AKI. The AKI incidence was 21.5% and was not significantly different between patients undergoing MCPB versus CCPB (21.9% versus 21.2%, p=0.948). The first CPB haematocrit was independently associated with AKI in the MCPB group (Relative Risk [RR]=0.484, 95% Confidence Interval [CI]=0.268-0.876, p=0.016); post-operative blood loss and inflammation were independently associated with AKI in the CCPB group (RR=1.005, 95%CI=1.003-1.007, p<0.001; RR=1.018, 95%CI=1.010-1.028, p<0.001). The MCPB system is not associated with a lower incidence of AKI in Asian patients undergoing CABG. Risk factors for AKI differed between patients using the MCPB and CCPB systems.

Excessive negative venous line pressures and increased arterial air bubble counts during miniaturized cardiopulmonary bypass: an experimental study comparing miniaturized with conventional perfusion systems

Miniaturized cardiopulmonary bypass (MCPB) is increasingly used in cardiac surgery, because it can lower clinically significant complications such as systemic inflammatory response, haemolysis and high transfusion requirements. A limitation of MCPB is the risk of excessive negative pressure in the venous line during volume depletion, probably leading to gaseous microembolism. In an experimental study with 24 pigs, we compared conventional open cardiopulmonary bypass (CCPB group, n = 11) with MCPB (n = 13). The same pump and identical tubing materials were used in both groups. Primary endpoints were pressure values in the venous line and the right atrium as well as the amount of air bubbles >500 µm. Secondary endpoints were biochemical parameters of systemic inflammatory response, ischaemia, haemodilution and haemolysis. Nearly 20% of venous pressure values were below -150 mmHg and approximately 10% of the right atrial pressure values were below -100 mmHg in the MCPB group, during the experiment. No such low values were observed in the CCPB group. In addition, the number of large arterial air bubbles was higher in the MCPB group compared with the CCPB group (mean ± standard deviation [SD]: 13 444 ± 5709 vs 0.9 ± 0.6, respectively; P < 0.001). Bubble volume was also significantly larger during MCPB compared with CCPB (mean ± SD: 1522 ± 654 vs 4.1 ± 2.5 µl, respectively; P < 0.001). Blood levels of interleukin-6, free haemoglobin and creatine kinase were significantly higher in the CCPB group compared with the MCPB group. Despite the benefits of MCPB regarding systemic inflammatory response and haemolysis, this technique is associated with excessive negative venous line pressures and a significant increase in the number and volume of arterial air bubbles compared with CCPB. Mini-perfusion systems and the management of MCPB require further refinements to avoid such adverse effects.

Advantages to Miniaturized Cardiopulmonary Bypass for Adult Cardiac Surgery

The development of cardiopulmonary bypass (CPB) and open heart surgery in the 1950s has benefited millions of people around the world over the last half century. However, it has been recognized since the beginning that there are detrimental effects to CPB. In an effort to minimize the effects of CPB, a miniaturized CPB (M-CPB) closed circuit system also known as closed circuit extracorporeal circulation (CCECC) has been developed as a strategy. In this review, we will look at the rationale behind the development of the miniaturized cardiopulmonary bypass circuits, the published results in comparison to both conventional CPB (C-CPB), and off pump Coronary Artery Bypass Grafting (OPCAB), and the surgical and perfusion strategies to incorporate this technique into everyday adult cardiac surgical practice.

Beating‐Heart Coronary Artery Bypass Grafting With Miniaturized Cardiopulmonary Bypass Results in a More Complete Revascularization When Compared to Off‐Pump Grafting

The technique of miniaturized cardiopulmonary bypass (M-CPB) for beating-heart coronary artery bypass grafting (CABG) is relatively new and has potential advantages when compared to conventional cardiopulmonary bypass (CPB). M-CPB consists of less tubing length and requires less priming volume. The system is phosphorylcholine coated and results in minimal pump-related inflammatory response and organ injury. Finally, this technique combines the advantages of the off-pump CABG (OPCAB) with the better exposure provided by CPB to facilitate complete revascularization. The hypothesis is that CABG with M-CPB has a better outcome in terms of complete coronary revascularization and perioperative results as that compared to off-pump CABG (OPCAB). In a retrospective study, 302 patients underwent beating-heart CABG, 117 (39%) of them with the use of M-CPB and 185 (61%) with OPCAB. After propensity score matching 62 patients in both groups were demographically similar. The most important intra- and early-postoperative parameters were analyzed. Endpoints were hospital mortality and complete revascularization. Hospital mortality was comparable between the groups. The revascularization was significantly more complete in M-CPB patients than in patients in the OPCAB group. Beating-heart CABG with M-CPB is a safe procedure and it provides an optimal operative exposure with significantly more complete coronary revascularization when compared to OPCAB. Beating-heart CABG with the support of a M-CPB is the operation of choice when total coronary revascularization is needed.

Aortic Surgery Using Total Miniaturized Cardiopulmonary Bypass

Few centers have attempted aortic surgery using miniaturized cardiopulmonary bypass (MCPB) systems due to concerns of air handling. The extra corporeal circuit optimized (ECCO) total MCPB system uses a venous air removal device and a parallel soft-shell reservoir that allows for venting of the heart. At our institution, total MCPB is used for all coronary artery bypass graft patients. Our objective was to assess the suitability of the ECCO total MCPB system during aortic surgery. Fifty consecutive and unselected aortic procedures using the ECCO system were undertaken. Surgical feasibility, air removal ability, and blood transfusion requirements were audited to determine the efficacy of this technique. The bypass time was 81.6 +/- 28.0 minutes and the ischemic time was 56.7 +/- 18.9 minutes. Total MCPB handled 1,910 +/- 404 mL of vented blood with 96 venous air removal device activations noted. The blood product transfusion rate was 12%, which was below the surgical transfusion rate for our unit. There were no complications. Aortic surgery can be undertaken safely and effectively using the ECCO total MCPB system.

Miniature cardiopulmonary bypass — the Hammersmith experience

The decision to embark on a miniature cardiopulmonary bypass programme requires careful planning. The objective of this paper is to present our experience and initial findings for consideration by our multidisciplinary peers, who may wish to implement this technology at their own hospitals. The paper reviews the evolution of our programme over the first 150 clinical cases and our current position on the advantages and disadvantages of miniature cardiopulmonary bypass.

Aortic Valve Replacement in a Dialysis-Dependent Jehovah's Witness: Successful Use of a Minicircuit, Microplegia, and Multimodality Blood Conservation Technique

We present the first reported case of an aortic valve replacement operation without blood transfusion in a 62-year-old Jehovah's Witness with dialysis-dependent chronic renal failure, severe anemia, severe aortic stenosis, and symptomatic angina with minimal exertion after an accident in which she suffered fractures of both her right arm and leg. She underwent successful valve replacement surgery after preoperative stabilization of her fractures and high-dose erythropoietin and iron supplement therapy preoperatively and postoperatively. The intraoperative blood conservation technique included a novel approach with a miniature cardiopulmonary bypass circuit and microplegia with limited hemodilution. High-risk valve surgery in patients who are Jehovah's Witnesses can be successful with a carefully planned multimodality blood conservation strategy.

Miniaturized Cardiopulmonary Bypass in Coronary Artery Bypass Surgery: Marginal Impact on Inflammation and Coagulation but Loss of Safety Margins

Inflammation and coagulation disturbances are common consequences of cardiopulmonary bypass (CPB). Recently, miniaturized closed CPB circuits without cardiotomy suction and venous reservoir have been proposed to reduce complication rates. We compared outcomes with conventional (CCPB) and miniaturized cardiopulmonary bypass (MCPB) after coronary artery bypass operations (CABG) with respect to inflammation and coagulation. Thirty patients (23% female; aged 67.9 +/- 9.0 years) were prospectively randomly assigned to undergo isolated CABG with CCPB or MCPB. Conventional CPB had a pump prime of 1, 600 mL. Miniaturized CPB consisted of a centrifugal pump, arterial filter, heparinized tubing, and oxygenator with a priming volume of 800 mL. Shed blood was removed by a cell-saving device and reinfused. Measurements included interleukin (IL)-2 receptor, IL-6, IL-10, tumor necrosis factor receptor 55 and 75, C reactive protein, leukocyte differentiation, d-dimers, fibrinogen, and thrombocytes at six time points. In both groups no major complication occurred. However, two dangerous air leaks occurred in the closed MCPB circuit, demonstrating the narrow safety margins. Operative handling was also more difficult owing to limitations in venting and fluid management. International normalized ratio (p = 0.03) and antithrombin III (p = 0.04) levels were elevated during CPB in the CCPB group, most likely owing to differences of the intraoperative anticoagulation management. Repeated measures analysis revealed that not a single parameter of inflammation or clinical outcome showed significant differences among groups. Use of a MCPB affected inflammation and coagulation variables only marginally and did not lead to clinical relevant changes as assessed by blood loss, need for blood products, and intensive care unit and clinical stays. However, safety margins for volume loss, air emboli, and weaning from CPB decrease, because of the closed MCPB circuit.

Cardiopulmonary Bypass: It’s Not the Size, It’s How You Use It! Review of a Comprehensive Blood-Conservation Strategy

Several of the manufacturers of cardiopulmonary bypass equipment have recently introduced new miniature cardiopulmonary bypass systems. New advancements in cardiopulmonary bypass technology are almost always of interest to the perfusion community. However, the question arises, what advantages do these systems offer over our present technology? The manufacturers claim that these new systems will add to our perfusion armamentarium by offering us an opportunity to further reduce priming volume and the surface area to which the blood is exposed. Our group, in the Department of Cardiac Surgery at Boston Medical Center has been involved in the development of a comprehensive blood conservation strategy since 1994. Our published data clearly demonstrates improved clinical outcomes using coated circuit technology as part of a comprehensive blood conservation strategy. In an effort to clearly evaluate this new technology, in this article we review our current technique at Boston Medical Center.

Evaluation of an improved blood-conserving POCT sampling system

To evaluate a modified point-of-care (POCT) testing i-STAT analyzing cartridge that connects directly to the sampling port of a blood-conserving sampling line. In an in vitro setup, blood samples were drawn from a blood-conserving sampling line connected to a miniature cardiopulmonary bypass (CPB) system. Blood collection from the sampling port was either performed with a syringe necessitating subsequent sample loading on a standard i-STAT cartridge (conventional procedure) or with a modified i-STAT sampling cartridge allowing blood flow from the sampling port directly into the cartridge (modified procedure). The loaded cartridges were subsequently inserted into the i-STAT Portable Clinical Analyzer for sample analysis. Multiple parameters such as blood gases, electrolytes, hematocrit, and glucose were measured. A series of 30 paired measurements was performed. Corresponding series of values were compared using linear regression analysis and Bland-Altman bias analysis (P < 0.05). Twenty-five complete measurement series consisting of 12 parameters (pH, pCO(2), pO(2), SO(2), base excess, bicarbonate concentration, sodium, potassium, ionized calcium, hemoglobin concentration, hematocrit, glucose) were evaluated. Linear regression analysis between the two sampling methods tested demonstrated an excellent correlation for all parameters (Pearson correlation coefficients: 0.859-0.999). Bias and precision between corresponding series showed clinically acceptable performance levels for all parameters. The modified i-STAT sampling cartridge allows reliable diagnostic blood sampling directly from a blood-conserving sampling line. The technique presented is also applicable to other POCT systems, thus reducing diagnostic blood loss because of the minimal amount of blood required for analysis.