Detection of Thromboembolic Events and Pump Thrombosis in HeartWare HVAD Using Accelerometer in a Porcine Model.

We have recently demonstrated that accelerometer-based pump thrombosis and thromboembolic events detection is feasible in vitro. This article focuses on detection of these conditions in vivo. In an open-chest porcine model (n = 7), an accelerometer was attached to the pump casing of an implanted HeartWare HVAD. Pump vibration was analyzed by Fast Fourier Transform of the accelerometer signals, and the spectrogram third harmonic amplitude quantified and compared with pump power. Interventions included injection of thrombi into the left atrium (sized 0.3-0.4 ml, total n = 35) and control interventions; pump speed change, graft obstruction, and saline bolus injections (total n = 47). Graft flow to cardiac output ratio was used to estimate the expected number of thrombi passing through the pump. Sensitivity/specificity was assessed by receiver operating characteristic curve. Graft flow to cardiac output ratio averaged 66%. Twenty-six of 35 (74%) thrombi caused notable accelerometer signal change. Accelerometer third harmonic amplitude was significantly increased in thromboembolic interventions compared with control interventions, 64.5 (interquartile range [IQR]: 18.8-107.1) and 5.45 (IQR: 4.2-6.6), respectively (p < 0.01). The corresponding difference in pump power was 3 W (IQR: 2.9-3.3) and 2.8 W (IQR: 2.4-2.9), respectively (p < 0.01). Sensitivity/specificity of the accelerometer and pump power to detect thromboembolic events was 0.74/1.00 (area under the curve [AUC]: 0.956) and 0.40/1.00 (AUC: 0.759), respectively. Persistent high third harmonic amplitude was evident at end of all experiments, and pump thrombosis was confirmed by visual inspection. The findings demonstrate that accelerometer-based detection of thromboembolic events and pump thrombosis is feasible in vivo and that the method is superior to detection based on pump power.

Long-term continuous flow mechanical biventricular support: 9 years and counting.

We report 2 continuous flow HeartWareTM left ventricular assist devices successfully used in a patient with advanced heart failure of giant cell myocarditis origin in a biventricular configuration. Despite technical challenges of adapting a left ventricular assist device engineered for systemic pressure to function as a right ventricular assist device, the addition of dynamic banding on the right ventricular assist device outflow graft allowed successful adaptation of afterload. This patient has now been on biventricular configuration support for 9 years, and remains stable to this day.

Pediatric coronary artery revascularization: a European multicenter study.

BACKGROUND: We sought to evaluate the hospital and midterm results of different surgical revascularization techniques in pediatric patients within the European Congenital Heart Surgeons Association. METHODS: From 1973 to 2011, 80 patients from 13 European Congenital Heart Surgeons Association centers underwent 65 pediatric coronary artery bypass grafting (PCABG) and 27 other coronary artery procedures (OCAP; 12 patients had combined PCABG and other coronary artery procedures). Excluded were patients with Kawasaki disease. Median age at the time of coronary procedure was 2.3 years (range, 2 days to 16.9 years); 33 patients (41.2%) were younger then 12 months. An emergency procedure was necessary in 34 patients (42.5%). RESULTS: Twelve patients (15%) died in the hospital; age at surgery (p=0.02) and the need for an emergent procedure (p=0.0004) were related to hospital mortality. Median follow-up time was 7.6 years (range, 0.9 to 23 years). There were 3 late cardiac deaths, all after a median time of 4 years (range, 9 months to 8.8 years) after PCABG. Fourteen patients (20.5%) presented with symptoms, including congestive heart failure (n=10) and angina (n=4), that were significantly associated with a low ejection fraction (p<0.001) and the presence of moderate or severe mitral valve regurgitation (p=0.0003). Six patients underwent a reintervention for impaired myocardial perfusion; all of them had a stenotic or atretic PCABG (p=0.001), and the majority were symptomatic (5 of 6 patients; 83.3%; p=0.001). CONCLUSIONS: Both PCABG and other coronary artery procedures are suitable surgical options in pediatric patients with impaired myocardial perfusion, which increases operative and midterm survival. Such population of patients needs to be followed for life to prevent and treat any possible cause of further myocardial ischemia.

Combined repair of upper sternal cleft and transposition of the great arteries in a newborn.

We report the case of a newborn with the unusual association of an upper sternal defect and transposition of the great arteries. Surgical correction of the cardiac disease consisted of the arterial switch procedure. The already less compliant bony thorax of the infant made direct approximation of the upper sternal defect only possible with adjuvant bilateral chondrotomy. Sternal cleft repair is advised during the very first weeks of life.

In vitro evaluation of PHISIO-coated sets for pediatric cardiac surgery.

OBJECTIVES: Phosphorylcholine coated cardiopulmonary bypass (CPB) circuits for children have been available for some years, but conflicting results regarding the inflammatory response have been reported. Accordingly, we aimed to investigate the effect of phosphorylcholine coating on the inflammatory response. DESIGN: Ten coated and nine uncoated pediatric CPB sets were tested in an in vitro CPB circuit model. The inflammatory response was assessed by serial assays of hemoglobin, hematocrit, leukocyte counts, platelet counts, activation of the complement system, activation of platelets measured as beta-thromboglobulin, activation of neutrophils measured as myeloperoxidase, activation of coagulation measured as prothrombin fragments 1+2, assessment of hemolysis measured as lactate dehydrogenase, and a panel of seven cytokines. Samples were obtained at baseline and after 15, 30, 60 and 120 minutes. RESULTS: There were no significant differences between the phosphorylcholine coated circuits and the uncoated circuits for any of the parameters during the observation period, although a potentially beneficial effect on platelets could not be ruled out. CONCLUSIONS: Phosphorylcholine coating of CPB equipment did not exert any beneficial effect on the inflammatory markers monitored.

Biomarker profile in off-pump and on-pump coronary artery bypass grafting surgery in low-risk patients.

BACKGROUND: The purpose of this study was to investigate the cytokine and chemokine profile in low-risk patients undergoing off-pump and on-pump coronary artery bypass grafting (CABG) surgery by use of a broad panel of cytokines and chemokines. METHODS: Eight consecutive blood samples were obtained from patients enrolled into a prospective, randomized study comparing off-pump and on-pump CABG in a low-risk population. Eleven patients from each group were randomly selected for analysis of 25 different cytokines and chemokines using multiplex technology. Data were compared using two-way repeated measures analysis of variance. RESULTS: Of the 25 biomarkers analyzed, 11 were not detected while 14 increased significantly in both groups. Only three mediators, eotaxin, macrophage inflammatory protein (MIP)-1beta, and interleukin (IL)-12 were significantly different between the two groups, increasing more in the on-pump than in the off-pump group (p < 0.001, p < 0.01, and p < 0.05, respectively). There was a marked, comparable increase in the concentrations of the cytokines IL-6, IL-10, IL-15, and IL-1Ra as well as the chemokines inducible protein (IP)-10, monokine induced by interferon gamma (MIG), monocyte chemoattractant protein 1 (MCP-1), and regulated on activation, normal T cell expressed and secreted (RANTES) in both groups (p < 0.001 for all). There was only a modest, but still statistically significant, increase in IL-8, tumor necrosis factors alpha, and IL-2R, without any intergroup differences. When corrected for hemodilution the production of the antiinflammatory biomarkers IL-1Ra and IL-10 were significantly higher in the on-pump group (p < 0.001 for both). CONCLUSIONS: The cytokine and chemokine production profile of the inflammatory response associated with CABG is largely similar using the off-pump and on-pump techniques in low-risk patients, but slightly higher concentrations of eotaxin, MIP-1beta, and IL-12 were found in the on-pump group.

Off-pump cardiac surgery abolishes complement activation.

BACKGROUND: This prospective randomized study compared the inflammatory response in patients undergoing elective on-pump and off-pump coronary artery bypass grafting. PATIENTS AND METHODS: Forty-four patients undergoing elective coronary artery bypass grafting were recruited with 22 patients randomized to on-pump heart surgery and 22 patients to off-pump coronary bypass surgery. Plasma levels of C3bc, the terminal SC5b-9 complement complex, myeloperoxidase, beta-thromboglobulin and prothrombin fragment F1 + 2 were measured before the operation, intraoperatively, at termination of the operation, and two hours post-operatively. RESULTS: Complement was markedly activated in the on-pump group as indicated by a significant increase in C3bc and SC5b-9 (p < 0.001 for both), whereas no complement activation was seen in the off-pump group (p = 0.001 between the groups). In contrast, both groups showed significant activation of neutrophils, platelets and coagulation, as indicated by an early increase in myeloperoxidase and a post-operative increase in beta-thromboglobulin and F1 + 2, respectively. Notably, there were no intergroup differences with regard to neutrophil and platelet activation, whereas coagulation activation was more pronounced in the off-pump group (p < 0.01). CONCLUSIONS: Off-pump surgery completely eliminated the heart-lung machine-induced complement activation. Neutrophils and platelets were equally activated in both groups, whereas coagulation was enhanced post-operatively in the off-pump group.

A life-threatening complication of the Nuss procedure for pectus excavatum.

We describe a delayed, life-threatening complication in a boy operated on using the Nuss-procedure 2 months earlier. On admittance he was in shock with cardiac tamponade. An immediate needle aspiration of blood from the pericardium was done before a median sternotomy. The Nuss-bar was removed, and we identified a 1.5-cm laceration in the adventitial layer of the ascending aorta as the source of bleeding. The tear was closed, and the patient had an uneventful recovery. Careful positioning of the bar is necessary to avoid complications. Measures must be taken postoperatively to confirm that the steel bar does not rotate.

Comparison of a Duraflo II-coated cardiopulmonary bypass circuit and a trillium-coated oxygenator during open-heart surgery.

BACKGROUND: Cardiopulmonary bypass (CPB) evokes a systemic inflammatory response. In attempting to improve the biocompatibility of the equipment, various methods to coat the inner surfaces of the CPB systems have been developed. The present study compares a Trillium Biopassive surface-coated Affinity oxygenator with a Duraflo II totally heparin-coated CPB system. METHODS: Low-risk patients admitted for primary coronary artery bypass grafting or aortic valve replacement were randomized to operation using the Trillium- or the Duraflo II-coated setups. Heparin concentration, complement activation (C3bc activation products and terminal complement complex (TCC)), platelet activation (platelet numbers and beta-thromboglobulin (BTG)), leukocyte activation (leukocyte numbers and myeloperoxidase (MPO)), coagulation (thrombin/antithrombin complexes (TAT)) and fibrinolytic activity (plasmin/alpha2-antiplasmin complexes (PAP)) were measured during CPB and two hours postoperatively. RESULTS: Platelet counts decreased during CPB, without significant intergroup differences. The median BTG concentration increased moderately in both groups and were slightly higher in the Trillium group during CPB (p < 0.05), but not postoperatively. Complement activation products (C3bc and TCC), leukocyte counts, MPO, TAT and PAP activity showed no differences between the two groups. CONCLUSIONS: There were small differences in the inflammatory response between the two extracorporeal circulation devices compared in this study.