Haemostasis alterations in coronary artery bypass grafting: Comparison between the off-pump technique and a closed coated cardiopulmonary bypass system

OBJECTIVESTo compare coagulation and fibrinolysis activation in off-pump coronary artery bypass operation and in patients in whom a closed phosphorylcoline-coated cardiopulmonary bypass system was applied. Cardiopulmonary bypass induces activation of coagulative and fibrinolytic systems, which together with intraoperative haemodilution augment the risk of postoperative bleeding and transfusion of blood products.METHODSThirty-six off-pump coronary artery bypass and 36 coronary artery bypass grafting patients in whom a closed, phosphorylcholine-coated cardiopulmonary bypass system with a closed-collapsible venous reservoir (Physio group) was used were prospectively enrolled. Activation of coagulation and fibrinolytic systems was assessed evaluating the release of prothrombin fragment 1.2 and plasmin-antiplasmin complex preoperatively (T0), 30 min after heparin administration (T1), 15 min after protamin administration (T2), 3 h after protamin administration (T3) and on postoperative days 1 (T4) and 5 (T5). Platelet function was evaluated through Platelet Function Analyzer 100®.RESULTSDuring the operation, prothrombin fragment 1.2 and plasmin-antiplasmin levels were slightly higher in the Physio group, the difference being not statistically significant. In the off-pump coronary artery bypass group, prothrombin fragment 1.2 was significantly higher at T3 (618.7 ± 282.7 vs 416.6 ± 250.2 pmol/l; P = 0.006), T4 (416.7 ± 278.8 vs 310.2 ± 394.6 pmol/l; P < 0.001) and T5 (629.3 ± 295.2 vs 408.4 ± 409.7 pmol/l; P = 0.002), and plasmin-antiplasmin was significantly higher at T4 (731.1 ± 790 vs 334 ± 300.8 ng/ml; P = 0.019) and T5 (1744.4 ± 820.7 vs 860.1 ± 488.4 ng/ml; P = 0.003). Platelet Function Analyzer 100® closure time values were significantly higher in the Physio group patients at T3 (131.3 ± 105.7 vs 215.6 ± 58.9 s; P = 0.002). The off-pump coronary artery bypass patients had greater chest tube drainage (874.3 ± 371.5 vs 629.1 ± 334.5 ml; P = 0.005). The mean priming volume was 1240 ± 215 ml in the Physio group. Much more Physio patients received red blood cell transfusions (14 vs 25 patient; P = 0.009), because of higher intraoperative transfusion rates (6 vs 15 patients; P = 0.016). Despite similar preoperative haemoglobin levels (13 ± 1.2 vs 12.6 ± 1.4 g/dl; P = 0.2), postoperative haemoglobin levels were significantly lower in the Physio group.CONCLUSIONSThe Physio cardiopulmonary bypass approach does not significantly alter haemostasis during the operation compared with off-pump coronary artery bypass providing a reduced activation in the postoperative period reducing also chest tube drainage. However, further priming volume reduction is required to decrease intraoperative red blood cell transfusion. © 2013 The Author 2013

Asymptomatic large left-atrial ball thrombus. Secondary to mitral stenosis.

We describe the very unusual case of a patient with a large, free-floating left-atrial thrombus secondary to severe mitral stenosis, in whom the peculiar symptoms and complications of a ball thrombus were absent. The patient's only symptom before the episode reported here was mild dyspnea, which was attributed to mitral stenosis. She experienced neither embolism nor syncope. While even her clinical signs did not indicate a left-atrial ball thrombus, both echocardiography and angiography showed a free-floating thrombus. Because of the risk of stroke and acute obstruction of the mitral valve, emergency surgery was performed upon diagnosis of the ball thrombus. The surgery, which consisted of removing the thrombus and replacing the mitral valve with a mechanical prosthesis, was uneventful. A computed tomographic brain scan prior to discharge did not detect any cerebral infarction

Blood damage related to cardiopulmonary bypass: In vivo and in vitro comparison of two different centrifugal pumps

Cardiopulmonary bypass (CPB) induces hemolysis and the activation of the inflammatory and coagulation systems. Several components of the CPB equipment may contribute to such phenomenon. We tested the effects of two differently designed centrifugal pumps (Bio-Pump, Medtronic and Revolution, Cobe) on several markers of hemolysis, coagulation, and inflammation: plasma free hemoglobin, prothrombin fragment 1.2, platelet factor 4, and P-selectin. Twenty patients requiring coronary artery bypass grafting were randomized to undergo CPB with one of the study centrifugal pumps, and 10 experiments (5 for each pump) were performed with a closed loop circuit to assess pumps' performances over 6 circulation hours using human blood. CPB induced a significant elevation of all the tested markers. Neither in the in vivo nor in the in vitro study were significant differences observed between the groups. Because the Revolution centrifugal pump, which was recently designed and distributed, produced results comparable with those obtained with the Bio-Pump, it should be considered as safe as the Bio-Pump to perform clinical CPB

Activation of the receptor activator of the nuclear factor-κB ligand pathway during coronary bypass surgery: Comparison between on- and off-pump coronary artery bypass surgery procedures

Objectives: The receptor activator of the nuclear factor kappa-B (NF-κB) ligand (RANKL), its membrane receptor RANK and its decoy receptor osteoprotegerin (OPG) are all members of the tumour necrosis factor family involved in bone metabolism and immune response. We evaluated the activation of the OPG/RANKL/RANK pathway in patients undergoing cardiac surgery with and without cardiopulmonary bypass (CPB). Methods: Twenty consecutive patients undergoing elective coronary artery surgery were enrolled in the study and assigned either to the on-pump or to the off-pump group. Pre- and postoperative serum levels of OPG and RANKL were evaluated by enzyme-linked immunosorbent assay; gene expression of OPG, RANKL, RANK and NF-κB p50 subunits were determined by real-time polymerase chain reaction in peripheral blood T-cells and monocytes. Results: Serum levels of OPG significantly increased after surgery in both groups, whereas serum levels of RANKL did not differ over time. T-cells from the on-pump group showed increased gene expression of OPG, RANKL and RANK after the intervention, whereas no mRNA variation for these genes was detected in T-cells from off-pump patients. Gene expression of p50 subunit increased in T-cells and monocytes from both groups. Conclusions: Cardiac surgery induces the activation of the OPG/RANKL/RANK pathway; both on- and off-pump procedures are associated with increased postoperative OPG serum levels and up-regulation of the NF-κB p50 subunit. © The Author 2013. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery

Antithrombin administration in patients with low antithrombin values after cardiac surgery: a randomized controlled trial.

Antithrombin (AT) concentrations are reduced after cardiac surgery with cardiopulmonary bypass compared with the preoperative levels. Low postoperative AT is associated with worse short- and mid-term clinical outcomes. The aim of the study is to evaluate the effects of AT administration on activation of the coagulation and fibrinolytic systems, platelet function, and the inflammatory response in patients with low postoperative AT levels. METHODS: Sixty patients with postoperative AT levels of less than 65% were randomly assigned to receive purified AT (5000 IU in three administrations) or placebo in the postoperative intensive care unit. Thirty patients with postoperative AT levels greater than 65% were observed as controls. Interleukin 6 (a marker of inflammation), prothrombin fragment 1-2 (a marker of thrombin generation), plasmin-antiplasmin complex (a marker of fibrinolysis), and platelet factor 4 (a marker of platelet activation) were measured at six different times. RESULTS: Compared with the no AT group and control patients, patients receiving AT showed significantly higher AT values until 48 hours after the last administration. Analysis of variance for repeated measures showed a significant effect of study treatment in reducing prothrombin fragment 1-2 (p = 0.009; interaction with time sample, p = 0.006) and plasmin-antiplasmin complex (p < 0.001; interaction with time sample, p < 0.001) values but not interleukin 6 (p = 0.877; interaction with time sample, p = 0.521) and platelet factor 4 (p = 0.913; interaction with time sample, p = 0.543). No difference in chest tube drainage, reopening for bleeding, and blood transfusion was observed. CONCLUSIONS: Antithrombin administration in patients with low AT activity after surgery with cardiopulmonary bypass reduces postoperative thrombin generation and fibrinolysis with no effects on platelet activation and inflammatory response