Surface heparin treatment of the decellularized porcine heart valve: Effect on tissue calcification.

Tissue calcification is a major cause of failure of bioprosthetic heart valves. Aim of this study was to examine whether surface heparin treatment of the decellularized porcine heart valve reduces tissue calcification. Fresh porcine aortic heart valves were dissected as tissue discs and divided into four groups. Group A: controls without treatment, Group B: decellularization only, Group C: decellularization and glutaraldehyde cross-linking, Group D: decellularization and glutaraldehyde cross-linking followed by surface heparin treatment. After implantation in New Zealand White rabbits for 60 days, the explanted heart valve discs from the different study groups underwent a series of histological examinations as well as determination of calcium content by the methyl thyme phenol blue colorimetric method. Results of the explanted heart valve discs for the Von Kossa staining demonstrated that in Group A the heart valve tissue was the most severely stained with black color, whereas in Group D there was hardly any area that was stained black after implantation indicating the least tissue calcification. Furthermore, the inflammatory cells identified by the Hematoxylin-eosin staining appeared to be the least in Group D. The average tissue calcium content was highest in Group A (0.197 ± 0.115 µmol mg-1 ), modest in Group B (0.113 ± 0.041 µmol mg-1 ), and Group C (0.089 ± 0.049 µmol mg-1 ), and the lowest in Group D (0.019 ± 0.019 µmol mg-1 , p < 0.05). These results suggest that surface heparin treatment tends to reduce tissue calcification of the dellellularized porcine heart valve in a rabbit intramuscular implantation model. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 400-405, 2017.

Intraoperative cell salvage during cardiac surgery is associated with reduced postoperative lung injury.

OBJECTIVES: In addition to its blood-sparing effects, intraoperative cell salvage may reduce lung injury following cardiac surgery by removing cytokines, neutrophilic proteases and lipids that are present in cardiotomy suction blood. To test this hypothesis, we performed serial measurements of biomarkers of the integrity of the alveolar-capillary membrane, leucocyte activation and general inflammation. We assessed lung injury clinically by the duration of postoperative mechanical ventilation and the alveolar arterial oxygen gradient. METHODS: Serial measurements of systemic plasma concentrations of interleukin-6 (IL-6), myeloperoxidase, elastase, surfactant protein D (SP-D), Clara cell 16 kD protein (CC16) and soluble receptor for advanced glycation endproducts (sRAGEs) were performed on blood samples from 195 patients who underwent cardiac surgery with the use of a cell salvage (CS) device (CS, n = 99) or without (CONTROL, n = 96). RESULTS: Postoperative mechanical ventilation time was shorter in the CS group than in the CONTROL group [10 (8-15) vs 12 (9-18) h, respectively, P = 0.047]. The postoperative alveolar arterial oxygen gradient, however, was not different between groups. After surgery, the lung injury biomarkers CC16 and sRAGEs were lower in the CS group than in the CONTROL group. Biomarkers of systemic inflammation (IL-6, myeloperoxidase and elastase) were also lower in the CS group. Finally, mechanical ventilation time correlated with CC16 plasma concentrations. CONCLUSIONS: The intraoperative use of a cell salvage device resulted in less lung injury in patients after cardiac surgery as assessed by lower concentrations of lung injury markers and shorter mechanical ventilation times.

Effects of cell-saving devices and filters on transfusion in cardiac surgery: a multicenter randomized study.

BACKGROUND: Cell-saving devices (CS) are frequently used in cardiac surgery to reduce transfusion requirements, but convincing evidence from randomized clinical trials is missing. Filtration of salvaged blood in combination with the CS is widely used to improve the quality of retransfused blood, but there are no data to justify this approach. METHODS: To determine the contribution of CS and filters on transfusion requirements, we performed a multicenter factorial randomized clinical trial in two academic and four nonacademic hospitals. Patients undergoing elective coronary, valve, or combined surgical procedures were included. The primary end point was the number of allogeneic blood products transfused in each group during hospital admission. RESULTS: From 738 included patients, 716 patients completed the study (CS+filter, 175; CS, 189; filter, 175; neither CS nor filter, 177). There was no significant effect of CS or filter on the total number of blood products (fraction [95% confidence interval]: CS, 0.96 [0.79, 1.18]; filter, 1.17 [0.96, 1.43]). Use of a CS significantly reduced red blood cell transfusions within 24 hours (0.75 [0.61,0.92]), but not during hospital stay (0.86 [0.71, 1.05]). Use of a CS was significantly associated with increased transfusions of fresh frozen plasma (1.39 [1.04, 1.86]), but not with platelets (1.25 [0.93, 1.68]). Use of a CS significantly reduced the percentage of patients who received any transfusion (odds ratio [95% confidence interval]: 0.67 [0.49, 0.91]), whereas filters did not (0.92 [0.68, 1.25]). CONCLUSIONS: Use of a CS, with or without a filter, does not reduce the total number of allogeneic blood products, but reduces the percentage of patients who need blood products during cardiac surgery.

Pulsatile cardiopulmonary bypass and renal function in elderly patients undergoing aortic valve surgery†.

OBJECTIVES: To evaluate if pulsatile cardiopulmonary bypass (CPB) has any protective influence on renal function in elderly patients undergoing aortic valve replacement (AVR). METHODS: Forty-six patients (≥ 75 years old) with aortic valve stenosis underwent AVR with either pulsatile perfusion (PP) or non-pulsatile perfusion (NP) during CPB. Haemodynamic efficacy of the blood pump during either type of perfusion was described in terms of the energy equivalent pressure and the surplus haemodynamic energy. Urine samples were collected before surgery, at sternum closure, and at 2 and 18 h of intensive care unit stay to detect acute kidney injury markers. Perioperative urine levels of N-acetyl-ß-D-glucosaminidase (NAG), kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin (NGAL) were assessed together with plasma creatinine, creatinine clearance (CCr) and 24-h haemodynamic monitoring. Normally distributed continuous variables were described as mean ± standard deviation and non-normally distributed data were presented as the median [25th-75th percentiles]. RESULTS: PP was characterized by a significantly higher amount of surplus haemodynamic energy transferred to the patients (P < 0.001), with lower mean systemic vascular resistance during CPB (P = 0.020) and during 18 h postoperatively (group-P = 0.018). No difference was found between pre- and postoperative CCr in the PP group (71 ± 23 vs 60 ± 35 ml/min, P = 0.27), while its statistically significant perioperative decrement was observed in the NP group (67 ± 24 vs 45 ± 15 ml/min, P < 0.001). The PP group showed significantly lower urinary levels of NAG at 18 h postoperatively (P = 0.008), and NGAL at sternum closure (P = 0.010), 2 h (P < 0.001) and 18 h (P = 0.015) postoperatively. CONCLUSIONS: Short-term PP in elderly patients showed higher safety for renal physiology than NP, resulting in better maintenance of glomerular filtration and lower renal tissue injury.

The effect of pulsatile cardiopulmonary bypass on lung function in elderly patients.

PURPOSE: Cardiopulmonary bypass is still a major cause of lung injury and delay in pulmonary recovery after cardiac surgery. Although it has been shown that pulsatile flow induced by intra-aortic balloon pumping is beneficial for preserving lung function, it is not clear if the same beneficial effect can be accomplished with pulsatile flow generated in the extracorporeal circuit. Therefore, we investigated the effect of pulsatile flow, produced by a centrifugal pump, on lung function in elderly patients. METHODS: Serial measurements of lung biomarkers Clara cell 16 kD protein, surfactant protein D, and elastase were performed on blood samples from 37 elderly patients (≥75 years) who underwent elective aortic valve replacement surgery with CPB, either with pulsatile perfusion or continuous perfusion. Pulmonary function was assessed by postoperative ventilation time, the arterial blood oxygenation (PaO2/FiO2), the alveolar-arterial oxygen gradient (Aa-O2 gradient) and the pulmonary vascular resistance indexed by body surface area (PVRi). RESULTS: There was no difference in lung function between both groups, as assessed by the postoperative ventilation time, the PaO2/FiO2 ratio, and the Aa-O2 gradient. The PVRi, however, was significantly lower in the pulsatile perfusion group 15 mins after the administration of protamine (p<0.05). The plasma concentrations of the lung biomarkers increased during surgery and peaked at 1 h ICU, there were however no differences between groups. CONCLUSIONS: Pulsatile flow does not seem beneficial to postoperative lung function in elderly patients. Moreover, pulsatile flow does not affect lung function on a subclinical level as assessed by lung biomarkers.

The utility of lung epithelium specific biomarkers in cardiac surgery: a comparison of biomarker profiles in on- and off-pump coronary bypass surgery.

BACKGROUND: Despite continuous improvements in materials and perfusion techniques, cardiac surgery still causes lung injury and a delay of pulmonary recovery. Currently, there is no gold standard for quantifying cardiac surgery induced lung injury and dysfunction. Adding objective measures, such as plasma biomarkers, could be of great use here. In this study the utility of lung epithelium specific proteins as biomarkers for lung dysfunction was evaluated. METHODS: Serial measurements of plasma concentrations of Clara cell 16 kD (CC16) protein, Surfactant protein D (SP-D), Elastase and Myeloperoxidase were performed on blood samples from 40 patients who underwent coronary artery bypass grafting with cardiopulmonary bypass (CABG, n = 20) or without cardiopulmonary bypass (OPCAB, n = 20). RESULTS: The increase of SP-D and CC16 between pre-operative concentrations and concentrations at the end of cardiopulmonary bypass, correlated with the Aa-O2 gradient at 1 hour on the ICU (Rs = 0.409, p = .016 and Rs = 0.343, p = .043, respectively).Furthermore, SP-D and CC16 were higher in CABG than in OPCAB at the end of surgery [8.96 vs. 4.91 ng/mL, p = .042 and 92 vs. 113%, p = .007, respectively]. After 24 h both biomarkers returned to their baseline values. CONCLUSIONS: Our results show that increases in plasma of SP-D and CC16 correlate with clinical lung injury after coronary artery bypass surgery. Therefore, lung epithelium specific proteins seem to be a useful biomarker for measuring lung injury in the setting of cardiac surgery.

Effect of minimized perfusion circuit on brain injury markers carnosinase and brain-type fatty binding protein in coronary artery bypass grafting patients.

A minimized perfusion circuit (MPC) has proven to be superior to the conventional circulatory perfusion bypass (CCPB) as it reduces the blood-material interaction and hemodilution. Until now not much is known about impact these different perfusion systems have on the brain. The objective of this study is to determine carnosinase and brain-type fatty binding protein (BFABP) activity as novel specific biomarkers for ischemic brain tissue damage and how their activity differs during and after MPC and CCPB as well as to compare the inflammatory response of both perfusion systems. In a prospective pilot study, 28 patients undergoing coronary artery bypass grafting were randomly divided into an MPC group (n = 14) and a CCPB group (n = 14). Blood samples were taken before, during, and after operation until the fifth postoperative day. The brain biomarker carnosinase was determined by measuring the rate of histidine production from the substrate homocarnosine, whereas BFABP and interleukin-6 were determined by enzyme-linked immunosorbent assay (ELISA). C-reactive protein (CRP) and endothelin-1 were determined by enzyme immunoassay. The mean serum carnosinase activity was significantly higher in MPC (0.57 ± 0.34 nM histidine/mL/min) as compared with the CCPB group (0.36 ± 0.13 nM histidine/mL/min) at the end of operation (P = 0.02). The BFABP did not show any difference between the two groups in the immediate postoperative period until the second postoperative day. From that time point onward, it showed a steep increase in the CCPB group (581.3 ± 157.11 pg/mL) as compared with the concentrations in the MPC group (384.6 ± 39 pg/mL) (P = 0.04). The inflammation markers interleukin-6 and CRP showed a similar pattern in both groups without significant difference. In contrast, the leukocyte count on operation day and endothelin-1 on the first postoperative day were significantly higher in the CCPB group (P = 0.01, P = 0.03, respectively). MPC showed a significant higher and stable serum carnosinase activity during extracorporeal circulation as compared with the CCPB due to less hemodilution and a better preserved oxygen capacity. As a consequence, the antioxidant stress during MPC is limited as compared with CCPB, which means less brain tissue damage reflected by a lower BFABP release. Except endothelin-1 and leukocyte count, the inflammatory response of the MPC and CCPB was equal.

Preseeding of human vascular cells in decellularized bovine pericardium scaffold for tissue-engineered heart valve: an in vitro and in vivo feasibility study.

Human vascular cells from saphenous veins have been used for cell seeding on the synthetic scaffolds for constructing tissue-engineered heart valve (TEHV). However, little is known about the seeding of human vascular cells on bovine pericardium, a potential natural scaffold for TEHV. This study was aimed to assess the basic in vitro and in vivo characteristics of the human vascular cells seeded on decellularized bovine pericardium. In vitro, bovine pericardium samples with cell seeding were inspected on day 7, 14, and 21 by histology, scanning electron microscopy, and immunohistochemistry. In vivo, experiments were performed in nude mice by bilateral dorsal incision for the implantation of decellularized bovine pericardium with and without cell seeding. Results demonstrated that a total of 8-10 × 10(6) cells were obtained within 4-5 wk by the primary co-culture, which were detected positive for von Willebrand factor, α-smooth muscle actin antibodies, and fibronectin, indicating the presence of endothelial cells, smooth muscle cells, and fibroblasts, respectively. In vitro, the seeded cells showed a steady increase of endothelial activity from day 1 to day 7 and remained stable until day 21. After 30 days of implantation in vivo, the cells on the decellularized bovine pericardium could differentiate directionally and show all the identities of human endothelial cells, smooth muscle cells, and fibroblasts. These results indicate that the human vascular cells from the saphenous vein are an optional cell source for seeding on decellularized bovine pericardium scaffold for constructing TEHV.

PUCA pump and IABP comparison: analysis of hemodynamic and energetic effects using a digital computer model of the circulation.

The pulsatile catheter pump (PUCA pump) is a left ventricular assist device that provides additional flow to the left ventricle. It is usually run in order to ensure a counterpulsation effect, as in the case of the intra-aortic balloon pump (IABP). Because of this similarity, a comparison between the PUCA pump and the IABP was conducted from both the hemodynamic and energetic points of view. Numerical models of the two devices were created and connected to the CARDIOSIM cardiovascular simulator. The PUCA and IABP models were then verified using in vivo experimental data and literature data, respectively. Numerical experiments were conducted for different values of left ventricular end systolic elastance (Els) and systemic arterial compliance (Csa). The energetic comparison was conducted taking into account the diastolic pressure time index and the endocardial viability ratio. Hemodynamic results expressed as cardiac output (CO) and mean coronary blood flow (CBF) show that both the IABP and the PUCA pump efficacy decrease with higher values of Els and Csa. The IABP especially shows higher sensitivity to these parameters, to the extent that in some cases CO actually drops and CBF does not increase. On the other hand, for lower values of Csa, IABP performance improves so much that the PUCA pump flow needs to be increased in order to ensure a hemodynamic effect comparable to that of the IABP. Energetic results show a trend similar to the hemodynamic ones. The study will be continued by investigating other energetic variables and the autonomic response of the cardiovascular system.

Clinical effectiveness of centrifugal pump to produce pulsatile flow during cardiopulmonary bypass in patients undergoing cardiac surgery.

Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate whether the Rotaflow centrifugal pump produces effective pulsatile flow during CPB and whether the pulsatile flow in this setting is clinically effective in adult patients undergoing cardiac surgery. Thirty-two patients undergoing CPB for elective coronary artery bypass grafting were randomly allocated to a pulsatile perfusion group (n = 16) or a nonpulsatile perfusion group (n = 16). All patients were perfused with the Rotaflow centrifugal pump. In the pulsatile group, the centrifugal pump was adjusted to the pulsatile mode (60 cycles/min) during aortic cross-clamping, whereas in the nonpulsatile group, the pump was kept in its nonpulsatile mode during the same period of time. Compared with the nonpulsatile group, the pulsatile group had a higher pulse pressure (P < 0.01) and a fraction higher energy equivalent pressure (EEP, P = 0.058). The net gain of pulsatile flow, represented by the surplus hemodynamic energy (SHE), was found much higher in the CPB circuit than in patients (P < 0.01). Clinically, there was no difference between the pulsatile and nonpulsatile groups with regard to postoperative acute kidney injury, endothelial activation, or inflammatory response. Postoperative organ function and the duration of hospital stay were similar in the two patient groups. In conclusion, pulsatile CPB with the Rotaflow centrifugal pump is associated with a small gain of EEP and SHE, which does not seem to be clinically effective in adult cardiac surgical patients.

An in vitro model for studying neutrophil activation during cardiopulmonary bypass by using a polymerase chain reaction thermocycler.

The accurate temperature control of a polymerase chain reaction (PCR) thermocycler was exploited in developing an in vitro model to study neutrophil activation during cardiopulmonary bypass. Neutrophils from 12 volunteers underwent temperature changes in a PCR thermocycler (37 degrees C for 30 minutes, 28 degrees C for 60 minutes, and then 37 degrees C for 90 minutes). Different co-incubates were applied to neutrophils, as follows: Group A: phosphate-buffered saline solution; Group B: platelet activating factor (PAF) ; Group C: platelet-depleted plasma; Group D: platelet-depleted plasma + PAF; and Group E: platelet-rich plasma. Membrane-bound elastase (MBE) activity was measured every 30 minutes throughout the experiment. MBE activity decreased significantly after hypothermia, compared with the baseline level (p < 0.001), and it resumed an increase after re-warming. Among all co-incubates, platelet-rich plasma was the most potent pro-inflammatory stimulus to neutrophils. A linear correlation was found between MBE and platelet count in platelet-rich plasma (p = 0.004). A novel in vitro model involving a PCR thermocycler has been proved to be reliable in the study of neutrophil activation during cardiopulmonary bypass. The model could possibly be used as an alternative to animals in the development of new drugs to combat neutrophil damage to tissues and organs during cardiopulmonary bypass in cardiac surgery.

Leucocyte filtration of salvaged blood during cardiac surgery: effect on red blood cell function in concentrated blood compared with diluted blood.

OBJECTIVE: Leucocyte filtration of salvaged blood has been suggested to prevent patients from receiving activated leucocytes during auto-transfusion in cardiac surgery. This study examines whether leucocyte filtration of salvaged blood affects the red blood cell (RBC) function and whether there is a difference between filtration of the concentrated and diluted blood on RBC function. METHODS: Forty patients undergoing cardiac surgery with cardiopulmonary bypass were randomly divided into a group receiving leucocyte filtration of concentrated blood (High-Hct, n=20) and another group receiving leucocyte filtration of the diluted blood (Low-Hct, n=20). During operation, all the salvaged blood, as well as the residual blood, from the heart-lung machine was filtered. In the High-Hct group, blood was concentrated with a cell saver prior to filtration, whereas in the Low-Hct group, blood was filtered without concentration. RBC function was represented by RBC aggregation and deformability measured by a laser-assisted optical rotational cell analyser and by the RBC 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) contents with conventional biochemical tests. RESULTS: Leucocyte filtration of diluted blood with a low haematocrit (14+/-4%) did not affect RBC function. However, when the concentrated blood with a high haematocrit (69+/-12%) was filtered, there was a reduction of ATP content in RBCs after passing through the filter (from 1.45+/-0.57 micromol g(-1) Hb to 0.92+/-0.75 micromol g(-1) Hb, p<0.05). For patients who received the concentrated blood, their in vivo RBC function did not differ from those who received diluted blood. CONCLUSIONS: Leucocyte filtration of the diluted salvaged blood during cardiac surgery does not affect RBC function, but it tends to deplete the ATP content of RBCs as the salvaged blood has been concentrated prior to filtration.

Favorable effects of the detergent and enzyme extraction method for preparing decellularized bovine pericardium scaffold for tissue engineered heart valves.

Bovine pericardium has been extensively applied as the biomaterial for artificial heart valves and may potentially be used as a scaffold for tissue-engineered heart valves after decellularization. Although various methods of decellularization are currently available, it is unknown which method is the most ideal one for the decellularization for bovine pericardium. We compared three decellularization methods, namely, the detergent and enzyme extraction (DEE), the trypsin (TS), and the Triton X-100 and sodium-deoxycholate (TSD) method, to examine their efficacy on cell removal and their preservation of the mechanical function and the tissue matrix structure. Results indicated that decellularization was achieved by all the three methods as confirmed by hematoxylin-eosin staining, scanning electron microscopy, as well as quantitative DNA measurement. However, TS and TSD methods resulted in severe structural destruction of the bovine pericardium as shown by von Gieson staining and Gomori staining. Furthermore, both TS and TSD methods changed the mechanical property of the bovine pericardium, as evidenced by a lower elastic modulus, maximal-stress, maximal-disfiguration, maximal-load, and maximal-strain. In conclusion, the DEE method achieved both a complete decellularization and preservation of the mechanical function and tissue structure of the bovine pericardium. Thus, this method is superior to either the TS or the TSD method for preparing decellularized bovine pericardium scaffold for constructing tissue-engineered heart valves.

Heparin coating of small-caliber decellularized xenografts reduces macrophage infiltration and intimal hyperplasia.

Small-caliber decellularized xenografts with surface heparin coating are known to reduce in vivo thrombogenicity. This study was performed to examine whether heparin coating on the small-caliber decellularized xenografts would reduce macrophage infiltration and intimal hyperplasia. In a rabbit model of bilateral carotid implantation, each of the animals (n = 18) received a heparin-coated decellularized xenograft from a canine carotid artery on one side and a nonheparin-coated one on the other side. These experiments were terminated respectively at 1 week (n = 6), 3 weeks (n = 6), and 12 weeks (n = 6). Results showed that, compared with the nonheparin-coated grafts, the heparin-coated grafts had significantly less macrophage infiltration 1 week after implantation, identified by the mouse antirabbit macrophage antibody (RAM11)-positive cells on the vascular wall, covering all the proximal, middle, and distal parts of the grafts (P < 0.01). Moreover, the heparin-coated grafts also showed less deposition of proliferation cell nuclear antigen (PCNA)-positive cells on the vascular wall, indicating less cell proliferation, which was significant not only at 1 week (P < 0.01) but also at 12 weeks (P < 0.01). Intimal hyperplasia, measured by the intimal : media (I : M) ratio, was found similar in both groups at 1 and 3 weeks. However, the I : M ratio was significantly lower in the heparin-coated group than in the nonheparin-coated group at 12 weeks, especially in the proximal anastomosis area (0.76 +/- 0.12 vs. 0.345 +/- 0.06, P < 0.01). Heparin coating of small-caliber decellularized xenografts is associated with an early reduction of macrophage infiltration and intimal hyperplasia in a rabbit model of bilateral carotid artery implantation for 12 weeks. Thus, heparin coating appears to deliver not only the antithrombogeneity but also the antiproliferative property for small-caliber decellularized xenografts.

Change in kidney morphology after ischemia/reperfusion in a sheep model of acute heart failure supported by pulsatile catheter pump / 中国组织工程研究

BACKGROUND: Acute renal failure following heart failure assisted circulation have been extensively reported. However, little data have been available concerning morphological analysis of kidney tissues under that condition.OBJECTIVE: To observe morphological change of ischemia/reperfusion kidney in a sheep pulsatile catheter (PUCA) pump short-term support for heart failure model and explore causes of acute renal failure in assisted circulation patients.DESIGN, TIME AND SETTING: Self-contrast animal experiment was performed at the laboratory of Department of Cardiothoracic Surgery, Renji Hospital of Shanghai Second Medical University between July 2003 and April 2004.MATERIALS: PUCA pump was provided by Gerhard Rakhorst, Professor of Biomedical Engineering, University of Groningen.METHODS: After ischemic heart failure in 10 sheep was induced successfully and subsequently ischemia/reperfusion kidney was developed, PUCA pump was activated to support the hemodynamics for 3 hours.MAIN OUTCOME MEASURES: Hemodynamic parameters were monitored and recorded before thoracotomy, heart failure, and every 45 minutes after the support. Kidney biopsy specimens for light and electron microscopy were obtained 3 hours after support.RESULTS: PUCA pump support was successful in 7 of 10 sheep for 3 hours. During support with the PUCA pump,Hemodynamic parameters gradually restored to normal and stable condition, and blood pressure was close to baseline at the end of experiment. On both light and electron microscopy examination, mild acute kidney change was observed after ischemia/reperfusion. Cytosis in renal glomerulus associated with vasodilatation hyperemia, endepidermis in renal tubules hydropic degeneration, vasodilatation hyperemia and Interstitial edema in renal medulla were the main findings.CONCLUSION: PUCA pump could successfully maintain the hemodynamics for 3 hours in a sheep acute heart failure model,but pathological change in ischemia/reperfusion kidney was remained. It is impossible to predict prognosis of renal function on hemodynamic data alone during support.

Influence of mechanical cell salvage on red blood cell aggregation, deformability, and 2,3-diphosphoglycerate in patients undergoing cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Mechanical cell salvage is increasingly used during cardiac surgery. Although this procedure is considered safe, it is unknown whether it affects the red blood cell (RBC) function, especially the RBC aggregation, deformability, and the contents of 2,3-diphosphoglycerate (2,3-DPG). This study examines the following: (1) whether the cell salvage procedure influences RBC function; and (2) whether retransfusion of the salvaged blood affects RBC function in patients. METHODS: Forty patients undergoing cardiac surgery with cardiopulmonary bypass were randomly allocated to a cell saver group (n = 20) or a control group (n = 20). In the cell saver group, the blood aspirated from the wound area and the residual blood from the heart-lung machine were processed with a continuous-flow cell saver before retransfusion. In the control group this blood was retransfused without processing. The RBC aggregation and deformability were measured with a laser-assisted optical rotational cell analyzer and 2,3,-DPG by conventional laboratory test. RESULTS: The cell saver procedure did not influence the RBC aggregation but significantly reduced the RBC deformability (p = 0.007) and the content of RBC 2,3-DPG (p = 0.032). However, in patients receiving the processed blood, their intraoperative and postoperative RBC aggregation, deformability, and 2,3-DPG content did not differ from those of the control patients. Both groups of patients had a postoperative drop of RBC function as a result of hemodilution. CONCLUSIONS: The mechanical cell salvage procedure reduces the RBC deformability and the cell 2,3-DPG content. Retransfusion of the processed blood by cell saver does not further compromise the RBC function in patients undergoing cardiac surgery with cardiopulmonary bypass.

Implantation of decellularized small-caliber vascular xenografts with and without surface heparin treatment.

Heparin treatment of decellularized xenografts has been reported to reduce graft thrombogenicity. However, little is known about the in vivo comparison of heparin-treated with non-heparin-treated xenografts, especially for small-caliber vascular implants. We implanted either a heparin-treated or a non-heparin-treated canine carotid artery as bilateral carotid xenograft in rabbits (n = 24). Small-caliber xenografts (3 approximately 4 mm) were decellularized by enzymatic and detergent extraction and were further covalently linked with heparin. During implantation, thrombosis rate was 4% in the heparin-treated xenografts and 25% in the non-heparin-treated xenografts after 3 weeks (P < 0.05). After 6 months, it was 8 versus 58%, respectively (P < 0.01). Both heparin-treated and non-heparin-treated xenografts harvested at the end of 3 and 6 months showed a satisfactory cellular reconstruction of either smooth muscle cells or endothelial cells. These results indicate that heparin treatment of the small-caliber decellularized xenograft reduces the in vivo thrombogenicity. Both heparin-treated and non-heparin-treated xenografts seem to undergo a similar cellular remodeling process up to 6 months.

Numerical simulation of hemodynamic changes during beating-heart surgery: analysis of the effects of cardiac position alteration in an animal model.

Hemodynamic instability, mostly due to vertical lifting of the heart, is usually observed during beating-heart surgical procedures. However, some hemodynamic parameters, such as coronary blood flow, are not routinely measured. A digital computer model of the circulation able to simulate and analyze the effects of heart lifting and the Trendelenburg maneuver, and thus supply detailed hemodynamic information to the clinicians would provide a useful analytical tool. A lumped parameters model of the circulation was applied to both beta-blocked and not beta-blocked pigs. The results confirmed a drop of cardiac output and coronary flow during heart lifting and a rise of both variables after the Trendelenburg maneuver for beta-blocked animals. In not beta-blocked pigs, the analysis was more complex but the model reproduced experimental data and permitted coronary flow to be estimated. These results showed the feasibility of numerical simulation for specific circulatory conditions encountered during beating-heart surgery.