Foreign material reaction to BioGlue® as a possible cause of cardiac tamponade.

We describe the case of a 65-year-old female patient who underwent aortic valve reconstruction for aortic valve stenosis. During the operation, repair of a left ventricular laceration produced by a left ventricular vent was necessary. BioGlue® (CryoLife, Atlanta, GA, USA) and pledgeted sutures were used for repair. Pericardial effusion with signs of cardiac tamponade developed five months later. The patient was treated successfully by the removal of all foreign material and part of the BioGlue®. Microbiological findings were sterile. Histology showed a chronic granulomatous inflammatory response suggesting a foreign material reaction to BioGlue® as the cause of the effusion. Though all visible material was removed, the risk of pericardial effusion still persists as part of the BioGlue® remained within the ventricular wall.

Transmyocardial laser revascularization combined with intramyocardial endothelial progenitor cell transplantation in patients with intractable ischemic heart disease ineligible for conventional revascularization: preliminary results in a highly selected small patient cohort.

OBJECTIVE: Transmyocardial laser revascularization for angina relief and intramyocardial autologous endothelial progenitor cell injection for neoangiogenesis may offer a new treatment strategy for patients with intractable ischemic heart disease. METHODS: Transmyocardial laser revascularization and intramyocardial injection of bone marrow-derived CD133+ cells was performed in six highly symptomatic patients. Transmyocardial laser channels were created and isolated CD133+ cells were injected intramyocardially. All patients were followed up for a minimum of 6 months postoperatively. RESULTS: One patient died shortly after the operation due to refractory heart failure. In the five survivors, CCS class improved as well as left ventricular ejection fraction. Left ventricular end-diastolic volume and myocardial perfusion varied between the patients. All patients described a considerable improvement in quality of life postoperatively. Repeated 24-hour Holter monitoring revealed no significant arrhythmias. CONCLUSIONS: In this small patient cohort, intramyocardial CD 133+ cell injection combined with transmyocardial laser revascularization led to an improvement in clinical symptomatology in all patients and in left ventricular function in 4 out of 5 patients, with an unclear effect on myocardial perfusion. Caution is advised when employing this therapy in patients with severely depressed left ventricular function.

Impact of graft size and commissural resuspension height on aortic valve competence in valve-sparing aortic replacement under physiological pressures.

BACKGROUND: Valve competence in valve-sparing aortic root replacement has been described as being influenced by commissural height as well as graft size. The aim of this study was to investigate the impact of a gradual reduction of commissural height and graft diameter on aortic insufficiency under physiological conditions in an IN VITRO model. METHODS: Porcine aortic valves were reimplanted into a tubular graft and a native commissural height was obtained. Subsequently the height was reduced by 10 % and 20 %, respectively. To investigate the impact of graft size, a 30 % reduction of the prosthesis diameter was carried out in valves with both native and reduced commissural heights. All conditions were investigated under pulsatile flow simulation and static pressure exposure. RESULTS: Reduction of commissural height caused regurgitation at both 10 % and 20 % lower heights, which was more pronounced in grafts with 20 % reduction. Graft undersizing resulted in significant reflux, with regurgitation even occurring with valves in a native commissural position. CONCLUSIONS: Valve competence is impaired both by the reduction of commissural height and by reduced graft size. In particular, reimplantation of aortic valves into undersized grafts promotes valve insufficiency even if commissural height is well adjusted.

Contained rupture of the aorta in acute Stanford type A aortic dissection causing right ventricular wall dissection.

We describe a rare case of an acute aortic type A dissection after previous aortic valve replacement and coronary artery revascularization complicated by a contained rupture and right ventricular wall dissection. Although preoperatively echocardiography and CT scan described a pericardial hematoma, intraoperatively no intrapericardial hematoma was found; instead an extended right ventricular wall dissection caused by a large thrombus formation within the right ventricular muscle layers was demonstrated. After replacement of the ascending aorta and removal of the thrombus as the sole treatment for right ventricular wall dissection, the two dissected layers of the right ventricular wall were contracting synchronously again.

Delayed pericardial tamponade, mitral insufficiency and VSD after stab wound to the heart.

We report a case of delayed pericardial tamponade and presentation of a mitral insufficiency and traumatic ventricular septal defect (VSD) after a cardiac stab wound in an attempted suicide. Delayed tamponade in combination with a VSD and mitral valve injury is a rare complication after a stab wound to the heart. Normal echocardiographic findings, no murmur at admission and relatively benign clinical conditions may be misleading after cardiac trauma. The presented case links the rapid deterioration of the clinical condition and the development of a pericardial effusion to a Valsalva maneuver.

Impact of graft size and resuspension level of the commissures on aortic insufficiency after reimplantation of the aortic valve.

BACKGROUND: In addition to the size of the graft, the resuspension of the commissures has been described as important for valve function in valve-sparing aortic root replacement procedures. This study describes the influence of a stepwise reduction of the fixation level of the commissures within the graft as well as a stepwise reduction of graft size on valve insufficiency. METHOD: Porcine aortic valves were reimplanted into a tubular graft and the height of the commissures was reduced in a stepwise manner. In a second series of experiments, the diameter of the grafts was reduced by 30 % and 50 %. RESULTS: A reduction of the commissure heights by 10 % and 20 % caused a significant increase in reflux water. Using the criteria of homograft preparation, a 10 %, but not a 20 %, reduction was tolerated. The coaptation level of the valve became increasingly lower, indicating a higher risk for late valve incompetence. A reduction of the prosthesis diameter by 30 % and 50 % did not result in insufficiency of the valve but it lowered the coaptation level. CONCLUSION: Resuspension of the commissures within the graft has a more important impact on early failure rates than the choice of graft size.

Serum S100B levels in patients after cardiac surgery: possible sources of contamination.

BACKGROUND: S100B protein is considered to be a potential marker of brain damage. The aim of our study was to determine the contamination effect of retransfused blood on the serum S100B concentrations in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) and to differentiate between this simple contamination effect and its possible enhancement by haemolysis. METHODS: The first part of the study was performed in a group of 10 patients scheduled for coronary artery bypass grafting. Baseline S100B level was determined in a blood sample drawn from the radial artery before skin incision. After performing the distal anastomosis, additional blood samples were drawn from 1) the radial artery, 2) the aortic root catheter, 3) the pericardial space, and 4) CPB suction. To study the possible haemolytic effect on serum S100B levels, a second group of 23 patients was studied. S100B concentrations were determined in samples drawn simultaneously from the radial artery and bypass circuit after the end of CPB. Further samples from the retransfusion blood bag were analysed after one, two and three hours. RESULTS: Blood samples from the pericardial space and CPB suction exhibited significantly higher levels of S100B than the samples drawn from the peripheral artery and aortic root catheter in the first group of patients. No significant differences between the S100B levels in the peripheral blood and aortic root catheter were detected. In the second group, S100B was significantly elevated in the samples taken from the retransfusion blood bag in comparison with peripheral blood. S100B levels remained stable during the whole follow-up period. CONCLUSION: The results of our study show increased serum S100B levels caused by contamination originating in the mediastinal tissues. Storage of blood in the retransfusion bag and haemolysis can be excluded as sources of contamination. The role of S100B in perioperative monitoring of patients undergoing cardiac surgery remains to be established and should be confirmed by further studies using neuropsychological tests and imaging techniques.

A novel perfusion catheter for hybrid procedures in minimally invasive bypass surgery.

BACKGROUND: Combined off-pump bypass grafting and percutaneous coronary intervention (hybrid procedures) is supposed to be beneficial for high-risk patients. We developed a novel perfusion catheter to facilitate these hybrid interventions. METHODS: First, we tested coagulatory activation in vitro. Afterwards, 6 landrace pigs underwent active coronary perfusion of the LAD. In a second study, 15 pigs underwent off-pump bypass surgery (LIMA to LAD grafting) and the catheter was used to provide myocardial perfusion and prevent bleeding at the site of the coronary anastomosis. RESULTS: In the in vitro perfusion studies, no activation of coagulation or clotting occurred. Active coronary perfusion was feasible without signs of regional myocardial ischemia or coagulation over a 50-minute period. During off-pump bypass surgery, the catheter prevented bleeding in the operation field and facilitated the surgical procedure. CONCLUSION: The new perfusion catheter can optimize the conditions of off-pump bypass surgery by preventing bleeding in the operation field, maintaining myocardial perfusion and allowing direct angiographic control of the anastomosis. Therefore, this new technique could be an important tool to facilitate hybrid interventions.

Brain microembolic counts during extracorporeal circulation depend on aortic cannula position.

Thrombofibrinous and gaseous brain microemboli are commonly observed during extracorporeal circulation in patients undergoing cardiac surgery. Recent studies showed a preference of microemboli to the left hemisphere. We hypothesized that placement of the aortic cannula tip within the aorta descendens rather than in the aorta ascendens as commonly used reduces the number of microemboli to the brain and also reduces the side preference. Of 60 patients undergoing elective coronary artery bypass grafting primarily randomized to either a short aortic cannula (aorta ascendens) or an elongated one (aorta descendens), 29 (16 and 13) patients had complete and technically perfect continuous intraoperative transcranial Doppler sonography with embolus detection bilaterally. The number of high-intensity transient signals (HITS) was 994 +/- 2118 (mean +/- SD) for the short cannula group and was significantly lower with the elongated cannula (223 +/- 208; p < 0.02). HITS counts per min also differed significantly in favour of the aorta descendens group (p < 0.02), but there was an overlap. Thus, elongated cannulas can reduce, but not prevent microembolism to the brain. The side-to-side ratio of microemboli revealed more events in the left hemisphere, but this was similar in both groups. This suggests that individual anatomic factors may be responsible for this hemodynamically-mediated effect.

Cerebral microembolus generation in different extracorporeal circulation systems.

Microemboli generated during extracorporeal circulation (ECC) are likely to induce neurological sequelae. This study examines whether the choice of a distinct type of ECC can reduce intracerebral emboli counts. Middle cerebral artery blood flow during coronary artery bypass grafting was monitored continuously by transcranial Doppler ultrasound in 45 patients. The ECC systems used were a roller pump (n = 16), a centrifugal pump (n = 18) and a combination of centrifugal pump and heparin-coated ECC system (n = 11). Patients' characteristics as well as surgical and anesthesiological procedure did not differ between the groups. Total counts did not differ significantly between the three groups. Intraoperative events in individual patients may lead to massive embolus generation overcoming positive properties of a distinct ECC system.

Intraoperative embolus formation during cardiopulmonary bypass affects the release of S100B.

BACKGROUND: Intraoperative thromboembolism and the systemic inflammatory reaction are thought to play a role in causing cerebral dysfunction following cardiopulmonary bypass (CPB). Increased levels of S100B, an astroglial protein, have been linked to neuropsychological deficits after CPB. The present study investigated whether S100B release correlates with intraoperative embolus formation, thrombin formation, or the release of inflammatory parameters. METHODS: 40 patients undergoing coronary artery bypass grafting were included. Blood samples were taken before, during, and after CPB, and levels of S100B, thrombin-antithrombin complex (TAT), complement C5a, and interleukin 8 were analysed. Embolus formation was assessed by Doppler ultrasound at the arterial line of CPB. RESULTS: The release of S100B correlated with embolus count (r = 0.42; p = 0.009) and TAT formation (r = 0.71; p = 0.0001). The correlation of S100B with interleukin 8 (r = 0.58; p = 0.0001) was due to the dependence of both parameters on bypass time (r = 0.29; p = 0.075, partial correlation). A correlation of S100B with C5a formation could not be observed. CONCLUSIONS: S100B release is related to embolus and thrombin formation during CPB, indicating that thrombofibrinous embolism is involved in perioperative brain damage. Inflammatory parameters (i.e. interleukin 8 and C5a) seem to have no influence on S100B release.

Influence of different autotransfusion devices on the quality of salvaged blood.

BACKGROUND: Cardiopulmonary bypass causes a systemic inflammatory response and impaired hemostasis. We investigated whether intraoperative blood salvage with the cardiotomy suction contributes to these alterations. Furthermore, an alternative autotransfusion device (Haemonetics cell-saving device) was examined. METHODS: In 10 patients, interleukin-6, interleukin-8, tumor necrosis factor-alpha, thrombin-antithrombin complex, plasmin-antiplasmin complex, free hemoglobin, and the percentage of CD62+ thrombocytes were determined in the systemic circulation during cardiopulmonary bypass, in the cardiotomy suction tube, and in the blood from the cell-saving device. Additionally, bacterial contamination was examined. RESULTS: Median levels of interleukin-6 (52 versus 10 microg/L; p = 0.005), interleukin-8 (26 versus 20 microg/L; p = 0.017), tumor necrosis factor-alpha (24 versus 1 microg/L; p = 0.005), thrombin-antithrombin complex (113 versus 43 microg/L; p = 0.005), plasmin-antiplasmin complex (566 versus 489 microg/L; p = 0.022), and free hemoglobin (61 versus 30 mg/dL; p = 0.005) were higher in the cardiotomy suction tube compared with the systemic circulation. After processing the blood from the cell-saving device, interleukin-8, thrombin-antithrombin complex, and free hemoglobin remained above reference range, and in 90% of the cases bacterial contamination was observed. CONCLUSIONS: Cardiotomy suction additionally contributes to the release of proinflammatory cytokines, activation of coagulation, and hemolysis. Because blood salvage with a Haemonetics cell-saving device led to normalization of some, but not all, parameters and bacterial contamination was common, the alternative use seems at least questionable.

Response of the cellular immune system to cardiopulmonary bypass is independent of the applied pump type and of the use of heparin-coated surfaces.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with an activation of leukocytes. The extent of this activation was thought to depend on the applied CPB-circuit set-up. The present study comparatively evaluated the effect of roller pump, centrifugal pump, and uncoated and heparin-coated surfaces. METHODS: 73 patients were included, randomly assigned to 3 groups. In group A a roller pump was used, in group B a centrifugal pump, and in group C a centrifugal pump together with Carmeda heparin-coated surfaces. The quantitative (cell count) and the qualitative changes of leukocyte populations (subpopulations and expression of the CD126-, HLA-DR-, CD45 RO-, CD71 antigens) was comparatively analysed before, during, and following CPB. RESULTS: Groups A and B did not differ in leukocyte counts and the differences between groups B and C were restricted to single time points. Neither groups A and B, nor groups B and C differed significantly in the relative distribution of lymphocyte subpopulations or in the percentage of CD126+, HLA-DR+, CD45 RO+ and CD71+ leukocyte subpopulations. CONCLUSIONS: CPB affects the cellular immune system; however, this effect seems to be a physiological reaction, independent of the applied CPB circuit system.

Reduced release of tissue factor by application of a centrifugal pump during cardiopulmonary bypass.

The application of a centrifugal pump might lead to a reduced release of tissue factor (TF) due to less blood cell damage. This could result in a decrease in activation of the extrinsic pathway of coagulation and embolus formation. In the present study, 60 patients undergoing coronary artery bypass grafting were randomly assigned to a centrifugal or a roller pump. Plasma concentrations of TF, thrombin-antithrombin complex (TAT), and prothrombin fragments F1 + 2 were investigated before, during, and after cardiopulmonary bypass (CPB). Embolus detection was performed at the arterial line of CPB and transcranially by Doppler ultrasound. The centrifugal pump group revealed a lower TF release (area under the curve during CPB) when compared with the roller pump group [5661 (696-10359) vs 12681 (6383-17538) microg x min/l; median (lower - upper quartiles); P = 0.009]. In contrast, TAT and F1 + 2 formation did not differ between the groups, and neither did the total embolus count of both Doppler systems. Embolus counts did not correlate with TAT or F1 + 2 formation. In conclusion, the reduction in TF release by the application of a centrifugal pump seems to have little consequence on total thrombin formation. Since the applied Doppler systems seem to detect mainly microbubbles, conclusions regarding differences between the two pumps in the formation of thrombofibrinous clots cannot be drawn.

Response of the cellular immune system to cardiopulmonary bypass in vivo.

Cardiopulmonary bypass (CPB) is known to induce an inflammatory response. Previous studies reported an impairment of the cellular immune response with activation of neutrophils and changes in lymphocyte subpopulations. The objective of the present study was to investigate the effect of CPB on leukocyte activation in vivo. In 27 patients undergoing coronary artery bypass grafting, the quantitative and the qualitative response of leukocyte populations to CPB was analysed pre-, intra-, and postoperatively using flow cytometry. A significant increase in leukocyte counts was detected during CPB, resulting in a marked leukocytosis postoperatively. The total number of lymphocytes peaked in the early phase of CPB, followed by a significant decrease, mainly due to a loss in B and cytotoxic T lymphocytes. In contrast, the lymphocytopenia observed 8 h after protamin administration was mainly caused by a drop in the population of helper T lymphocytes. Activation of distinct cell populations could be detected during and following CPB. The results indicate an influence of CPB on the cellular immune system, however an immuno-suppression was detectable only transiently.

Primary structure and functional expression of the apical organic cation transporter from kidney epithelial LLC-PK1 cells.

Renal secretion of organic cations involves at least two distinct transporters, located in the basolateral and apical membranes of proximal tubule cells. Whereas the basolateral transporter has recently been cloned, sequence information about the apical type was not yet available. An organic cation transporter, OCT2p, was cloned from LLC-PK1 cells, a porcine cell line with properties of proximal tubular epithelial cells. OCT2p was heterologously expressed and characterized in human embryonic kidney 293 cells. OCT2p-mediated uptake of the prototypical organic cation [14C]tetraethylammonium ([14C]TEA) into 293 cells was saturable. There was a highly significant correlation between the Ki values for the inhibition of apical [14C]TEA uptake into LLC-PK1 cells and 293 cells transfected with OCT2p (r = 0.995; p < 0.001; n = 6). Although OCT2p is structurally related to OCT1r, the basolateral organic cation transporter from rat kidney, the transporters could be clearly discriminated pharmacologically with corticosterone, decynium22, and O-methylisoprenaline. The findings at hand suggest that OCT2 corresponds to the apical type of organic cation transporter. Reverse transcriptase-polymerase chain reaction indicates that mRNA of OCT1r is limited to non-neuronal tissue, whereas OCT2r, the OCT2p homologue from rat, was found in both the kidney and central nervous regions known to be rich in the monoamine transmitter dopamine.

Interindividual variations in cytokine levels following cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is associated with an inflammatory response, mainly caused by the trauma of surgery, contact of blood with the artificial surface of the circuit, and reperfusion injury, resulting in increased capillary permeability, respiratory distress, low cardiac output, and multiorgan failure. The inflammatory reaction includes an activation of the humoral and cellular immune system with enhanced release of cytokines. The present study focused on the effect of CPB on the time course of pro- and anti-inflammatory cytokines. In 20 patients undergoing coronary artery bypass grafting, the plasma concentration of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-2, IL-4, IL-6, IL-8, and IL-10 was investigated pre-, intra-, and postoperatively by enzyme-linked immunosorbent assay technique. With the exception of IFN-gamma, all the other cytokines could be detected in the patients plasma. However, neither TNF-alpha nor IL-1 beta and IL-2 revealed significant changes in concentration during the investigated time period. In contrast, IL-6 and IL-8 levels peaked early postoperatively, reaching median concentrations of 430 pg/ml (221 pg per ml/558 pg per ml; lower/upper quartiles, respectively) and approximately 12 pg/ml (0/17 pg/ml; lower/upper quartiles, respectively). IL-4 and IL-10, respectively, revealed maximal concentrations of approximately 2 pg/ml (0/39 pg/ml; lower/upper quartiles, respectively) and 208 pg/ml (76 pg per ml/380 pg per ml; lower/upper quartiles, respectively) immediately after protamine administration, preceding the maximal concentration of IL-6. The degree of the observed modulation of cytokine patterns during and after CPB seemed to be patient-dependent, since large interindividual variations in cytokine levels were observed, not only preoperatively, but especially during and following CPB. However, IL-6 and IL-10 showed the least interindividual variations, suggesting that these cytokines may give reliable information regarding modulation of the immune response following CPB and its consequences for the patient's outcome.

A comparative evaluation of the effect of pump type and heparin-coated surfaces on platelets during cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is associated with hemostatic disorders, mainly due to platelet function defects. In the present prospective study, platelet count and GMP-140 expression on platelets were investigated to comparatively evaluate the impact of different CPB-circuit systems on platelets. The study included 61 patients undergoing coronary artery bypass grafting, randomly assigned to 3 groups. In group A a roller pump, in group B a centrifugal pump, and in group C a centrifugal pump with a Carmeda heparin-coated CPB circuit was applied. Platelet count and GMP-140 expression were analysed pre, during, and following CPB. None of the tested CPB systems did affect platelet count. The percentage of GMP-140-positive platelets increased slightly early during CPB, whereas it decreased significantly postoperatively; group differences were observed between B and C after protamin administration. An advantage of the use of centrifugal pumps and heparin-coated circuits could not be proven with the present set-up. The results suggest that the benefit of the tested systems might depend on the operative procedure and management.

Efficacy and safety of low-dose propranolol versus diltiazem in the prophylaxis of supraventricular tachyarrhythmia after coronary artery bypass grafting.

OBJECTIVE: Supraventricular tachyarrhythmias (SVT) complicate postoperative management after coronary bypass surgery in about 30% of all patients. Though a prophylactic treatment both with beta-adrenergic blocking agents and the calcium antagonist diltiazem has been used for the prevention of post-operative SVT, no study yet has performed a prospective comparison of the efficacy of these therapies. METHODS: To investigate the prophylactic effect of either a calcium antagonist (diltiazem, 0.1 mg/kg per h i.v.) or a beta-adrenergic blocking agent (propranolol, 10 mg every 6 h postoperatively), we randomized prospectively 103 consecutive patients into three groups, the third one serving as a control group. Anti-arrhythmic medication was started with the procedure and was continued until the 3rd postoperative day. RESULTS: Preoperative conditions were the same for the three groups concerning age, extent of coronary heart disease, ventricular function and heart-related medication. There were no differences in intraoperative parameters or postoperative enzyme patterns. Diltiazem was ineffective in preventing SVT, the incidence being exactly the same as in the control group (35%). Propranolol reduced the occurrence of SVT significantly (7%, P < 0.05). Furthermore, patients treated with diltiazem needed positive inotropic support more often in the first hours after surgery than patients of the control group (30% vs 5%, P < 0.01). CONCLUSIONS: The perioperative administration of low-dose propranolol is considered a safe and effective drug prophylaxis to avoid the occurrence of SVT after bypass surgery.