Full Heparinization Research Articles

Endovascular Treatment of Blunt Traumatic Thoracic Aortic Injury

Blunt traumatic thoracic aortic injury (BTTAI) is a lethal injury associated with a prehospital mortality of 80% to 90%. Patients arriving in the emergency room and considered appropriate to undergo emergency open surgical repair still have a mortality rate of 15% to 30% because of severe associated injuries. Conventional open surgical repair requires a left thoracotomy, single lung ventilation, aortic-cross clamping and unclamping, with or without the adjunct use of partial or full cardiopulmonary bypass and systemic heparinization. All this leads to significant physiological stress and surgical trauma resulting in perioperative complications such as major blood loss, coagulopathy, myocardial infarction, stroke, respiratory failure, renal failure, bowel infarction, and paraplegia. Despite advances in anesthesia, critical care medicine, and surgical techniques, a recent meta-analysis showed no definite improvement in operative mortality over the past decade, following open surgical repair in patients with BTTAI. Endovascular repair of BTTAI does not require a thoracotomy, single lung ventilation, aorticcross clamping and unclamping, or systemic heparinization. As a result, endovascular repair of BTTAI has emerged as an effective, minimally invasive treatment alternative, especially in patients with severe concomitant injuries, which may be prohibitive to open surgical repair. Recent published studies have shown that endovascular repair of BTTAI is associated with lower morbidity, mortality, stroke, and paraplegia/paraparesis rates, when compared with open surgical repair of BTTAI.

Clinical and biomaterial evaluation of hyaluronan-based heparin-bonded extracorporeal circuits with reduced versus full systemic anticoagulation in reoperation for coronary revascularization

This prospective randomized study compares full and reduced heparinization on novel hyaluronan-based heparin-bonded circuits vs. uncoated controls under challenging clinical setting including biomaterial evaluation. 100 patients undergoing reoperation for coronary artery bypass grafting were allocated into two equal groups (n = 50): Group one was treated with hyaluronan-based heparin bonded preconnected circuits (Vision HFOGBS, Gish, California, USA) and Group two with identical uncoated controls (Vision HFO, Gish, USA). In the study group, half of the patients (n = 25) received low-systemic heparin (125 IU/kg, ACT >250 s) or full dose like control group. Blood samples were collected after induction of anesthesia (T1) and heparin administration before cardiopulmonary bypass (CPB) (T2), 15 min after initiation of CPB (T3), before cessation of CPB (T4), 15 min after reversal with protamine (T5), and the first postoperative day at 08: 00 h (T6). Platelet counts were preserved significantly better at T5, T6 in hyaluronan groups (P < 0.05 vs. control). Serum IL-2 levels were significantly lower at T4, T5 in both hyaluronan groups and C3a levels at T4 and T5 only in low-dose group (P < 0.05). Troponin-T levels in coronary sinus blood demonstrated well preserved myocardium in hyaluronan groups. No significant differences in thrombin-antithrombin levels were observed between full and low-dose heparin groups at any time point. Amount of desorbed protein was 1.41 +/- 0.01 in full and 1.43 +/- 0.01 in low dose vs. 1.78 +/- 0.01 mg/dl in control (P < 0.05). Hyaluronan-based heparin-bonded circuits provided better clinical outcome and less inflammatory response compared with uncoated surfaces. Reduced systemic heparinization combined with hyaluronan-based heparin-bonded circuits is feasible and clinically well tolerated.

Eculizumab Therapy Results in Rapid and Sustained Decreases in Markers of Thrombin Generation and Inflammation in Patients with PNH

Paroxysmal Nocturnal Hemoglobinuria (PNH) is a clonal disorder of the bone marrow resulting from an acquired mutation in the PIG-A gene. The mutation decreases production of the glycosylphosphatidylinositol membrane anchor for a variety of membrane proteins. Loss of cell membrane CD59 and CD55 results in enhanced complement-mediated cell membrane injury. PNH is associated with an increased risk of venous (VTE) and arterial thrombosis. Eculizumab, a monoclonal antibody to complement C5, has received FDA approval for the treatment of PNH. Recent published data demonstrates a 92% reduction in thrombotic events with the use of eculizumab. However, the mechanism for this reduction is unclear. We have enrolled eight PNH patients (pts) in an ongoing IRB-approved study on the effect of eculizumab treatment on markers of thrombin generation and inflammation. Patients were treated by the FDA-approved treatment protocol with blood samples obtained prior to treatment day 1 and prior to each dose on days 8, 15, 22, 29, 43 and 90. Patients receiving anticoagulants and corticosteroids were continued on their baseline medications. Plasma samples were assayed for D-dimers (D-D), thrombin-antithrombin complex (TAT), interleukin 6 (Il-6) by ELISA and tissue factor microparticles (TFMP) by impedance-based flow cytometry. Mean age of pts was 40.8 years (26–70); 6 male pts and 2 females. One patient had a prior history of VTE; 4 pts were receiving anticoagulants (1 full dose low molecular weight heparin (LMWH), 2 prophylactic LMWH, 1 warfarin) and 2 pts were receiving prednisone at the initiation of eculizumab. The effect of eculizumab on markers of hemostatic activation and inflammation was evaluated using Wilcoxon signed-rank test and multilevel models.Results: Pretreatment levels of D-D were significantly elevated in all but two of the patients who were receiving anticoagulants. Pretreatment Il-6 levels were significantly elevated in all but two patients taking prednisone. With eculizumab treatment, there was a statistically significant decrease in LDH (p=0.0001), D-D (p=0.0057), TAT (0.0138) and Il-6 (p=0.0362) during the 4 week induction phase of treatment (days 1–29). TAT levels significantly decreased by day 8 (p=0.008), with little subsequent change to day29 and day 90. All decreases in D-D, TAT, Il-6 and LDH were sustained in the maintenance phase of treatment (days29–90). Plasma TFMP were detectable and significantly increased in all patients prior to treatment. There was a statistically significant decrease in TFMP by day 8 (p=0.0234) and TFMP levels remained below pretreatment levels for the duration of the study (p=0.030). However, there were wide individual variations in TFMP levels over the course of treatment. There were significant Spearman correlations between changes in D-D and TAT (0.521; p<0.0001), in D-D and IL-6 (0.4400; p=0.0007). Changes in LDH did not correlate with changes in D-D, TAT, TFMP or Il-6. Changes in TFMP did not correlate with changes in markers of thrombin generation (TAT or D-D).Conclusion: Eculizumab treatment of patients with PNH results in a rapid decrease in plasma tissue factor microparticles, thrombin generation and inflammation. These changes appear to be independent of eculizumab suppression of RBC hemolysis as characterized by decreases in serum LDH. A direct relationship between plasma TFMP levels and thrombin generation in PNH patients could not be confirmed in this study. Taken together, these data indicate the broader impact of eculizumab treatment to suppress inflammation and prothrombotic activity in patients with PNH.

Comparison of primate and human ovaries retrieved by transplant techniques vs. current clinical protocol

OBJECTIVE: To compare human and primate ovaries retrieved by specialized transplant surgery retrieval techniques versus a current clinical protocol. DESIGN: Case-control study. MATERIALS AND METHODS: Ovary retrievals in primates and humans were conducted in accordance to two protocols. One protocol used human multi-organ donors, consented for research as ‘ovary donors’. Retrievals were conducted in collaboration with the NY Organ Donor Network at multiple institutions following standard organ donation protocols (minimum iv fluids, individual organ canulization, full heparinization, organ perfusion with specialized fluid, reperfusion with physiologic crystalloid, in vivo cooling and other measures). Live human subject ovary retrievals were conducted at regularly scheduled surgery according to an IRB approved clinical protocol for ovary cryopreservation that did not utilize specialized organ retrieval techniques other than cold transport media. The ovary is retrieved, transported in ice and then cryopreserved. Primate ovary retrievals were conducted according to both of these human techniques as well. RESULTS: Ovaries were retrieved in 24 Rhesus monkeys (48 ovaries) and 13 humans (26 ovaries). We compared the Hematoxylin and Eosin (H&E) stained slides of ovaries retrieved from primates and humans by the two retrieval protocols. There was no difference in the neutrophil invasion, vascular plugging, signs of ischemia, areas of necrosis, areas of edema, inflammation or any other differentiation between the 2 groups. CONCLUSIONS: Routine H&E staining techniques did not find any difference between the two retrieval techniques. Additional investigations are continuing in order to detect subtle differences in follicle condition and ovarian function.

A Third Generation of Ascending Aorta Dacron Graft: Preliminary Experience

To develop a preassembled biological valved conduit, a Dacron conduit was modified to be stored in glutaraldehyde without loss of blood impermeability. This study reports the preliminary experience with this "third generation" aortic Dacron graft. Eight patients underwent ascending aorta or root replacement using the new Triplex prosthetic conduit (Vascutek Terumo, Renfrewshire, Scotland) consisting of three layers. The inner layer is a standard uncoated woven Dacron graft (DuPont, Wilmington, DE); the outer layer is a standard expanded polytetrafluoroethylene graft. Both layers are fused together by a central layer of self-sealing elastomeric membrane. For its peculiar characteristics this graft has unique properties that allow it to be maintained in glutaraldehyde solution as well as in various storage solutions. None of the patients died or exhibited any neurologic event. The clinical inflammatory response was within the usual postoperative levels. The graft appeared slightly stiffer than the standard Dacron graft with similar handling and tailoring characteristics. Blood impermeability (even through the suture holes) was remarkably high. This prosthetic graft appeared to combine good handling and tailoring characteristics with a striking reduction of blood oozing through the fabric and suture hole, even at full heparinization.

Wirklich betrunken?

We report about a 42-year-old patient who was admitted to the emergency department because of suspected alcohol abuse. He declared himself to be drunk. He stated in his case history that he had suffered from right sided neck and facial pain for several days. The clinical examination revealed a left sided hemiparesis. Together with the demonstrated right hemispherical brain ischemia by computed tomography, a presumptive diagnosis of a dissection of the right internal carotid artery was made. This diagnosis was finally confirmed by ultrasound and magnetic resonance imaging. A therapy with full dose heparin was begun and oral anticoagulation was subsequently initiated. After two weeks of follow-up, the neurological deficiencies were partially regredient.

Hemodynamic and Echocardiographic Responses to Acute Interruption of Left Ventricular Assist Device Support: Relevance to Assessment of Myocardial Recovery

Assessment of myocardial recovery during left ventricular assist device (LVAD) support is difficult to perform both safely and effectively. We developed a test involving short-term interruption of LVAD support with measurements of several hemodynamic and echocardiographic parameters at rest and, whenever possible, after exercise, to investigate inotropic reserve. After full heparinization, the HeartMate I XVE device was switched off. MAP, heart rate (HR), ejection fraction (EF) and left ventricular dimensions were measured on switching off, after 5, 10 and 15 minutes, and after 6-minute walk (6MW). In total, 207 serial tests were performed on 22 patients. A total of 97.6% of the patients tolerated the tests. Of the 202 tolerated tests, 130 were performed on 16 patients who had their device explanted due to myocardial recovery (recovered group), and 72 on 6 patients who did not recover and were transplanted (non-recovered group). After device discontinuation there was an immediate drop in mean arterial blood pressure (MAP), a rise in HR, a reduction in EF and increases in ventricular dimensions. These changes tended to be more marked in the non-recovered group. After 6MW, the recovered group had a significant rise in HR and EF and a non-significant increase in MAP, whereas, the non-recovered group there was a significant drop in MAP compensated by a rise in HR. The distance walked in the recovered group was significantly higher (544 +/- 102 vs 418 +/- 109 meters, p < 0.05). MAP, pulse pressure and EF were strong predictive factors for recovery. Acute discontinuation of the device to assess recovery is safe and well tolerated and is followed by specific changes in hemodynamic and echocardiographic parameters. This helps in the assessment of recovery, particularly with regard to findings taken after exercise.

Elastomeric surgical sealant for hemostasis of cardiovascular anastomosis under full heparinization

We developed a novel surgical sealant, a viscous diisocyanated prepolymer, applicable to arterial hemostasis. The purpose of this study is to evaluate hemostatic effect of this surgical sealant under heparinized conditions. The effectiveness of this sealant was verified by applying it to the end-to-end anastomosis of canine carotid arteries. Five mongrel dogs were used. After a complete heparinization, the carotid arteries were clamped, divided, and end-to-end anastomoses were performed with four simple interrupted sutures. The sealant was coated on the anastomosis. After 5 min the clamps were removed and the hemostatic effect was evaluated. Three dogs were immediately subjected to macroscopic evaluation. Two dogs were subjected to angiography after 3 months and 16 months, respectively. No bleeding occurred in any of the anastomoses immediately after the removal of the clamp. Macroscopic finding revealed no leakage of the sealant into the lumen. Carotid angiography revealed patent anastomoses without stenosis. A novel surgical sealant exhibited rapid and potent hemostatic effect on a moisturized tissue under full heparinization.

Off-Pump Open Pulmonary Embolectomy for Patients with Major Pulmonary Embolism

Acute major pulmonary artery embolism (AMPE) requires rapid diagnosis and early intensive treatment to optimize patient outcomes. Most patients with AMPE and hemodynamic instability need open pulmonary embolectomy (OPE). We modified the technique of OPE to include a minimally invasive procedure without the use of cardiopulmonary bypass (CPB). From March 1988 to April 2006, we performed OPE on a total of 12 patients (21 sides) with AMPE. Seven patients (13 sides) underwent conventional OPE with CPB and 5 patients underwent off-pump OPE (OPPE), 4 (8 sides) with AMPE and 1 with catheter embolus with thrombosis. In patients who underwent conventional OPE, there was 1 hospital death in a patient with severe right ventricle dysfunction and 2 significant cases of airway bleeding. In patients who underwent OPPE, there was 1 case of minimal airway bleeding. Mean systolic pulmonary artery pressure in conventional OPE and OPPE patients, respectively, decreased from 50.3 +/- 14 mmHg and 35.4 +/- 6.6 mmHg pre-operatively to 41.7 +/- 20 and 28 +/- 3 mmHg postoperatively. During the long-term follow-up, there were 2 cancer-related deaths but no recurrence of PE. All surviving patients maintained functional class I (n = 10) or II (n = 1). Compared with conventional OPE, OPPE was effective for treating AMPE in our selected cases. Modification of conventional CPB and systemic full heparinization to minimal use of systemic heparinization without CPB may be helpful in treating selected patients with AMPE.

Acute Pulmonary Embolectomy Three Days following a Coronary Artery Bypass Graft Procedure

Pulmonary embolism is very rarely reported early after cardiac surgery, most probably due to full heparinisation during cardiopulmonary bypass. We report a 66-year-old man without thromboembolic history who presented three days after a coronary artery bypass grafting procedure with acute dyspnoea and haemodynamic instability. A CT scan confirmed paracentral bilateral pulmonary embolism requiring an urgent and successful embolectomy. Review of the literature confirms that pulmonary embolism may occur in up to 3% of post-cardiopulmonary bypass patients. The possibility of pulmonary embolism must be taken into consideration in post-cardiopulmonary bypass patients with acute onset of chest pain and respiratory insufficiency.

Peri-operative management of an adult patient with type 2N von Willebrand's disease scheduled for coronary artery bypass graft

We describe a patient with type 2N von Willebrand's disease scheduled for elective coronary artery bypass graft for severe three-vessel coronary artery disease with involvement of the left main stem. He was given a pre-operative bolus of 3000 IU factor VIII/Willebrand factor concentrate (approximately 40 IU.kg(-1)), followed by a continuous infusion of 3 IU.h(-1) (228 IU.h(-1)) before undergoing coronary surgery with full heparinisation and cardiopulmonary bypass. There were no intra-operative bleeding complications and only one unit of packed red blood cells was required postoperatively. Thromboprophylaxis with low-molecular weight heparin and aspirin was given and the infusion of factor VIII/von Willebrand factor concentrate continued for 2 days. As a result of haematological monitoring, heparin therapy was changed from prophylactic to therapeutic on day 5-6 and stopped on day 7.

Deferral of assessment of pulmonary embolism

We evaluated a simplified algorithm for safely postponing diagnostic imaging for pulmonary embolism (PE). At the index visit, patients were identified as being at high or low risk of PE; the former received full dosage low molecular weight heparin while the latter were left untreated until performance of diagnostic imaging (max 72 hours). During this period, no thromboembolic events occurred in low-risk patients (0/211, 0.% [upper 95% CI 0.9%]); only one event occurred in those at high-risk (1/125, 0.8% [upper 95% CI, 1.2]). Our study demonstrates that diagnostic imaging for PE can be safely deferred for up to 3 days.

Purpura fulminans in paroxysmal nocturnal haemoglobinuria

A 29-year-old woman with a 1-year history of paroxysmal nocturnal haemoglobinuria (PNH) presented to our accident and emergency department with pyrexia, a swollen left knee and small non-blanching purpuric lesions on her torso (top left). Blood cultures and knee aspiration were performed. She was commenced on flucloxacillin and gentamicin because of suspected staphylococcus infection. All cultures were negative. This may have been because she had been prescribed oral amoxicillin and metronidazole for her swollen knee the previous day. No blood cultures had been taken. Her rash continued to progress after admission; she continued to be pyrexial and unwell, despite the addition of imipenem, liposomal amphotericin and aciclovir. She was reviewed by a dermatologist and was commenced on prednisolone 1 mg/kg as a vasculitic process was suspected. Skin biopsies were taken, which showed skin necrosis, thrombosis and infarction without evidence of vasculitis (bottom). A diagnosis of purpura fulminans was made. She was commenced on recombinant activated protein C and full dose low molecular weight heparin. The lesions dramatically improved as shown by the second clinical picture, taken 48 h after the first (top right). She was continued on protein C for 7 d then fully anticoagulated with warfarin. The lesions completely resolved without scarring. She remained extremely prothrombotic over the next 12 months, developing multiple thrombi in hepatic vein and an axillary vein and infarcting her small bowel despite anti-coagulation. Her parents had normal thrombophilia screens. We conclude that she had purpura fulminans secondary to PNH causing a prothrombotic tendency.

The case of a migrating bullet

In February, 2006, a 22-year-old man was brought to our trauma resuscitation room. He reported having been shot twice in the back. On examination, his blood pressure and heart rate were 130/70 mm Hg and 80 bpm, respectively. He was awake, alert, and oriented. The gunshot wounds were in the right back, below the 12th rib, four fi ngerbreadths lateral to the midline. A thorough search revealed no other wounds. Both chest (fi gure A) and plain abdominal supine radiography showed a single foreign body. No free intra-peritoneal or intra-pericardial fl uid was detected by ultrasonography. The patient underwent an intravenous injected CT of the chest, abdomen, and pelvis. A single bullet was identifi ed lodged in the right paraspinal muscle. Otherwise, the images were interpreted as negative for intra-thoracic or intra-abdominal injuries. The second bullet wound was presumed to be a graze injury. Further imaging review showed a foreign body in the left thigh, asymmetry of the psoas muscles with fullness in the right compared with the left, and minimal fl uid around the vena cava. In the interim, the patient complained of diff use abdominal pain in the left upper quadrant and epigastrium. The pain migrated to the basal left chest. Vital signs were normal. Repeat chest radiography showed a new foreign body in the chest (fi gure B). The patient immediately underwent a repeat chest CT. This showed a bullet in the right ventricle. Plain radiography of the left leg showed that the foreign body had disappeared. An interventional team attempted, unsuccessfully, to remove the intra-cardiac bullet. A venogram showed no discernible injury in the vena cava. A repeat abdominal CT showed slightly increased haemoperitioneum with stranding around the right adrenal gland and posterior vena cava. Surgery was therefore delayed until the third post-injury day, when the patient underwent sternotomy and cardiotomy with cardiac bypass under full anticoagulation. Full heparinisation for cardiac bypass was considered safe after the venogram confi rmed integrity of the posterior wall of the vena cava. A 1 cm bullet was removed from behind a tricuspid valve leafl et. The patient was discharged on the 7th post-operative day. When seen for fi nal follow-up in, July, 2006, the patient had recovered fully without any complications. A review of the events leads us to assume that the second bullet traversed the psoas muscle and pierced the posterior aspect of the infra-hepatic vena cava, stopped, and fell into the left profunda femoris vein. The welldeveloped psoas muscle in this young man absorbed the majority of the potential energy, stopping the bullet in its tracts. Otherwise the bullet would have pierced the anterior wall of the vena cava, probably causing massive haemoperitoneum and haemodynamic instability. The migrating abdominal pain may have been related to the bullet obstructing mesenteric venous beds as it travelled via the inferior vena cava to the heart. This is an unusual and potentially serious complication of a bullet embolising through the venous system and to the heart. A fi rst review of the CT failed to identify the foreign body in the profunda femoris vein. The clinicians were focused on identifying retroperitoneal and intra-abdominal injuries, and none was immediately obvious. This case highlights the importance of a systematic review of all imaging by an experienced reader before clinical decisions are made. In addition, this case report emphasises the need to aggressively rule out anatomical traumatic lesions in patients with gunshot wound to the torso, until proven otherwise, by both clinical and advanced radiological examinations.

Relationship of Atrial Fibrillation and Stroke After Coronary Artery Bypass Graft Surgery: When is Anticoagulation Indicated?

Atrial fibrillation (AF) is considered as a risk factor for stroke after coronary artery bypass grafting operations. A retrospective search in our hospital's medical record database was done to identify patients with postoperative strokes who underwent coronary artery bypass grafting operations from January 1, 1993, until December 31, 2004. All cases were individually reviewed, and the temporal relationship between neurologic event and postoperative episodes of AF was determined. During the study period it was our consistent policy to use only Coumadin anticoagulation limited to patients who had persistent AF or were to be discharged in AF. Of the 2,964 coronary artery bypass grafting operations, 576 patients (19.4%) had AF and 32 patients (1.1%) suffered stroke. Seventeen stroke patients maintained normal sinus rhythm during their hospital stay. Of the remaining 15 patients, 9 presented with neurologic deficit before the first episode of AF, with 5 having intraoperative and 4 having postoperative stroke. Of the 6 patients with AF before neurologic event, three strokes occurred within 1 week after spontaneous conversion to normal sinus rhythm. One patient with preoperative and also with intraoperative AF who underwent emergency coronary artery bypass grafting woke up with stroke. In the remaining two cases, the AF or atrial flutter episodes lasted less than 6 hours each before the neurologic event. More aggressive anticoagulation as suggested in the published guidelines could not have prevented strokes in any of these 6 patients. This retrospective analysis does not support the use of aggressive anticoagulation, particularly full intravenous heparinization as a bridging therapy to decrease the already low incidence of postoperative strokes after routine coronary artery bypass grafting surgery.

Invited commentary

Although enhanced knowledge and technological advances are making the total correction for the majority of congenital heart defects routine and safe, either the initial implantation of a biological valved conduit or conduit replacement inevitably lead to repeat surgery and represent one of the more frustrating issues of our field in need of a long-term solution. For reconstruction of the right ventricular outflow tract, valved homograft conduits have the best track record and are considered the gold standard. However, for small patients, small sized homografts are scarce and even when larger ones can be downsized (ie, bicuspidized), they present limitations with regards to patient-conduit size mismatch and resistance to degeneration, and they fare as poorly as other known xenograft valves. The current article [1Schreiber C. Sassen S. Kostolny M. et al.Early graft failure of small-sized porcine-valved conduits in reconstruction of the right ventricular outflow tract.Ann Thorac Surg. 2006; 82: 179-186Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar] is the third clinical report on the Shelhigh No-React porcine-valved conduit, confirming the poor results already observed by others [2Ishizaka T. Ohye R.G. Goldberg C.S. et al.Premature failure of small-sized Shelhigh No-React porcine pulmonic valve conduit model NR-4000.Eur J Cardiothoracic Surg. 2003; 23: 715-718Crossref PubMed Scopus (34) Google Scholar, 3Pearl J.M. Cooper D.S. Bove K.E. Manning P.B. Early failure of the Shelhigh pulmonary valve conduit in infants.Ann Thorac Surg. 2002; 74: 542-548Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar], which lead the authors to abandon implantation in their own practice, and to discourage the use of this conduit by others. The fact that 62% of their patients were under 1 year of age illustrates the problem known to us all in finding appropriately sized small homografts, and this justifies their trial to find a better and more practical “off the shelf” alternative. However, just as with other xenografts, the authors found that the Shelhigh No-React formed an extensive neointimal peel leading to early conduit stenosis and failure, although gross calcification was not noted. Despite efforts by the manufacturers to produce a nonimmunogenic product, the presence of a nonspecific macrophage and granulocyte-mediated inflammatory response still pointed to a foreign-body reaction. Therefore, the concerns and condemnation of this conduit by the authors are validly argued and well illustrate the ongoing search for an ideal alternative to reconstruct the right ventricular outflow tract. Accordingly the inevitable life-long threat of multiple reoperations for any given patient and the associated risks continue to motivate many research groups to focus their efforts on the quest for the tissue-engineered grail (ie, the “perfect biological valve”). Curiously the authors gave no justification for full heparinization followed by oral anticoagulation to an international normalized ratio of 2 to 3 for at least 3 months, and they did not state if some patients eventually required longer anticoagulation and for which reasons. Most centers would agree that unless a proven advantage in terms of patient benefit or conduit longevity or both can be demonstrated with this practice, anticoagulation could and should be avoided for biological implants.

Thrombin generation during reperfusion after coronary artery bypass surgery associates with postoperative myocardial damage.

Cardiopulmonary bypass and coronary artery bypass grafting (CABG) result in significant thrombin generation and activation of fibrinolysis. Thrombin contributes to myocardial ischemia-reperfusion injury in animal studies, but the role of thrombin in myocardial damage after CABG is unknown. We measured thrombin generation and fibrin turnover during reperfusion after CABG to evaluate their associations with postoperative hemodynamic changes and myocardial damage. One hundred patients undergoing primary, elective, on-pump CABG were prospectively enrolled. Plasma prothrombin fragment F(1+2) and D-dimer were measured preoperatively and at seven time points thereafter. Mass of the Mb fraction of creatine kinase (Ck-Mbm) and troponin T (TnT) were measured on the first postoperative day. Reperfusion induced an escalation of thrombin generation and fibrin turnover despite full heparinization. F(1+2) during early reperfusion associated with postoperative pulmonary vascular resistance index. F(1+2) at 6 h after protamine administration correlated with Ck-Mbm (r = 0.40, P < 0.001) and TnT (r = 0.44, P < 0.001) at 18 h postoperatively. Patients with evidence of myocardial damage (highest quintiles of plasma Ck-Mbm and TnT) had significantly higher F(1+2) during reperfusion than others (P < 0.002). Logistic regression models identified F(1+2) during reperfusion to independently associate with postoperative myocardial damage (odds ratios 2.5-4.4, 95% confidence intervals 1.04-15.7). Reperfusion caused a burst in thrombin generation and fibrin turnover despite generous heparinization. Thrombin generation during reperfusion after CABG associated with pulmonary vascular resistance and postoperative myocardial damage.

Adhesion of thrombotic components to the surface of a clinically used oxygenator is not affected by Trillium coating

The Trillium coating is designed to minimize adsorption of protein and the attachment of cells and other particles. The present study was undertaken to investigate the effect of surface coating on the adhesion of thrombotic components (activated platelets, white blood cells and fibrin) to the surface of a clinically used oxygenator. Twenty patients undergoing elective coronary artery bypass grafting (CABG) were randomized to one of the two oxygenator groups: non-coated (NC, n = 10) or Trillium-coated (TC, n = 10). Platelet and white blood cell counts and factor XIIa concentrations were determined prior to the induction of anesthesia and at the end of cardiopulmonary bypass (CPB). Binding of activated platelets, white blood cells and fibrin to the artificial surfaces was quantified by means of antibody binding and histological validation was achieved by scanning electron microscopy. Patient demographic and CPB data were similar for the two groups. No significant differences between the groups were found for any of the tested thrombotic components. However, observations from our scanning electron microscopy suggested a release of formed particles from the Trillium-coated surface. Primary adhesion of activated platelets, white blood cells and fibrin to the artificial surface of the venous blood inlet from an oxygenator is not affected by the Trillium surface coating under conditions of full systemic heparinization.

Salvage autotransfusion in aortic surgery: initial studies using a disposable reservoir.

Transmission of disease by allogeneic transfusion can be avoided using several techniques by which a patient receives his own blood. Sixty patients undergoing aortic surgery consented to salvage interoperative autotransfusion. A mean of 895 ml shed blood was reinfused under full heparinization, representing 12-74 per cent of total blood loss. Bank blood requirements fell from 4.9 units to 3.4. No important haematological or clinical complications were noted (including coagulation studies) but haemolysis was detected 4 h postoperatively by plasma haemoglobin levels of 0.05 +/- 0.03 g/dl. This preliminary study confirms the applicability of salvage autotransfusion during elective vascular surgery by demonstrating an appreciable saving in bank blood transfusion (70 per cent).

Performance and Reliability of the CPB/ECMO Initiative Forward Lines Casualty Management System

The Cleveland Clinic Foundation CPB/ECMO Initiative Forward Casualty Management System is an economical, compact, transportable, disposable system designed to permit a rapid expansion of trauma management services requiring cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO) pulmonary support. The system, composed of a rotary blood pump, a pump motor driver, and an electronic control console as the blood pumping subsystem, also includes commonly used compatible commercial oxygenators, venous reservoirs, and cannulae. In vitro durability testing accumulated over 100 hours without failure. In vivo reliability was tested in 10 calves under general anesthesia during 6 hours of CPB and ECMO under full heparinization at nominal operating conditions of 4-5 l/min and 2-4 l/min blood flow respectively, and mean arterial pressures between 65 and 100 mm Hg. A mean time to failure of 57 hours was reached during the animal series. Results of these test series demonstrated that this system has the capability to reliably operate during a 6-hour conventional CPB or ECMO procedure, while providing flexibility and ease of use for the operator.