Assessment of the Impact of Skeletonization on Pleuropulmonary Changes after Bilateral Internal Thoracic Artery Harvest for Coronary Artery Bypass Grafting.

BACKGROUND AND AIMS: Skeletonization has been proposed as a technique to minimize the risk of sternal devascularization during bilateral internal thoracic artery harvest for coronary artery bypass grafting. The impact of this strategy on late radiologic pleuropulmonary changes has not been addressed. MATERIAL AND METHODS: Post-operative chest radiographs from patients (n = 253 per group) undergoing bilateral internal thoracic artery harvest using skeletonized and non-skeletonized techniques were reviewed by blinded radiologists. The primary outcome was the incidence of atelectasis and pleural effusion. Multivariable linear regression models were derived to assess the relationship of radiologic pleuropulmonary outcomes to patients and operative variables. RESULTS AND CONCLUSION: Patients in the skeletonized group were older (p < 0.0001), had a lower preoperative hematocrit (p = 0.014), had higher prevalence of peripheral vascular disease (p = 0.001), were of female gender (p = 0.015), underwent off-pump surgery (p < 0.001), had urgent/emergent status (p = 0.024), and had chronic obstructive pulmonary disease (p = 0.019). There was no difference in the incidence of post-operative complications, ventilation time, or intensive care unit stay. There was no difference in the severity of post-operative atelectasis in both groups. More patients in the non-skeletonized group had a grade 2/3 left pleural effusion on the late post-operative chest X-ray (p = 0.007). The independent effect of skeletonization on the development of a late left pleural effusion was significant (odds ratio = 0.558, 95% confidence interval = 0.359-0.866, p = 0.009). Skeletonization results in a decreased incidence of late post-operative left pleural effusion with no difference in early or late atelectasis. Further studies are warranted to assess the mechanism of these pleuropulmonary changes and the impact of other factors such as pleural violation during surgery.

A Matched-Paired Comparative Analysis of the Hemodynamics of the Trifecta and Perimount Aortic Bioprostheses.

BACKGROUND AND AIM OF THE STUDY: Current cohort studies comparing the Trifecta valve to alternative pericardial bioprostheses are limited by selection bias. The study aim was to determine if hemodynamics are improved after the aortic valve implantation of a Trifecta valve as compared to a standard pericardial valve, when evaluated using strict paired matching for specific key relevant confounders. METHODS: Valve hemodynamics were compared in patients undergoing implantation with a Trifecta or Perimount valve matched for left ventricular outflow tract (LVOT) diameter, gender, age, body size, and days since surgery, using a 1:1 matched-paired cohort analysis (n = 20 per group). RESULTS: Patients receiving a Trifecta valve had a larger increase in indexed stroke volume (SVi) relative to baseline compared to the Perimount patients (p = 0.013), in whom SVi was decreased. The mean transvalvular pressure gradient was lower in Trifecta patients despite the larger SVi (p = 0.02). The effective orifice area (EOA) and indexed EOA (EOAi) were significantly larger in Trifecta patients compared to Perimount patients (2.04 +/- 0.46 versus 1.77 +/- 0.45 cm2, p = 0.049; 1.10 +/- 0.22 versus 0.95 +/- 0.06 cm2/m2, p = 0.027, respectively), and there was a greater increase in EOA and EOAi from baseline (p = 0.010 for both). Severe prosthesis-patient mismatch (PPM) (EOAi < or = 0.65 cm2/m2) was seen in two (10%) of the Perimount cases, but in none of the patients with the Trifecta valve (p = 0.072). CONCLUSION: Trifecta valve implantation is associated with a significant improvement in EOA and a decreased incidence of PPM as compared to the Perimount valve. The superior hemodynamic outcomes observed support consideration of this valve for aortic valve replacement, particularly in patients with a small LVOT at risk for PPM.

Preventive strategies for atrial fibrillation after cardiac surgery in Nordic countries.

BACKGROUND AND AIMS: Atrial fibrillation is a common arrhythmia after cardiac surgery. It increases morbidity, length of hospital stay, and costs of operative treatment. Beta-blockers, sotalol, amiodarone, corticosteroids, and biatrial pacing have been shown to be efficient in the prevention of postoperative atrial fibrillation. The aim of this study was to find out how widely different prophylactic strategies for postoperative atrial fibrillation are used in Scandinavian countries. MATERIAL AND METHODS: An online link for a questionnaire was emailed to (214) cardiac surgeons in Finland, Sweden, Norway, Denmark, and Estonia to assess the use of prophylactic methods for postoperative atrial fibrillation. RESULTS: A total of 97 surgeons responded to the survey. Oral beta-blockers were routinely used for atrial fibrillation prophylaxis by 62% of responders. The main reasons for nonuse of beta-blockers were that responders were unconvinced of the evidence of benefit or they preferred some alternative prophylaxis. Intravenous beta-blockers were used frequently by 6% of responders. Amiodarone was used for prophylaxis by 18% of responders. Nonusers were unconvinced of its efficacy, were afraid of its complications, or found its use too cumbersome. Other prophylactic atrial fibrillation strategies that were used are as follows: sotalol by 2%, magnesium by 17%, corticosteroids by 1%, and atrial pacing by 11% of respondents. CONCLUSIONS: There is still widely varying implementation of strategies for atrial fibrillation prophylaxis among Scandinavian cardiac surgeons. Lack of confidence in the efficacy of these approaches is the main rationale for nonimplementation.

Deep hypothermic circulatory arrest: alternative strategies for cerebral perfusion. A review article.

Deep hypothermic circulatory arrest is an essential tool in the surgeon's armamentarium. There are essentially three strategies to address cerebral ischemia during arrest periods. Early surgical case series pioneered the option of complete anoxia with deep hypothermia. Subsequent innovators introduced the concept of retrograde perfusion of the cerebral vessels through the venous system, and others have advocated the use of selective and non-selective antegrade perfusion of the cerebral arteries. Clinical studies assessing outcomes of the three approaches are compromised by small patient numbers, retrospective design and surgeon bias. In this review, the authors will briefly discuss the conceptual basis of these strategies and the literature comparing these approaches in terms of key neurologic outcomes. The importance of this topic will emphasize the key role the perfusion community plays in establishing guidelines for best practice in circulatory arrest to go forward with education and research in this area.

Temperature management and monitoring practices during adult cardiac surgery under cardiopulmonary bypass: results of a Canadian national survey.

BACKGROUND: Mild to moderate systemic hypothermia is commonly used as a cerebral protective strategy during adult cardiac surgery. The benefits of this strategy for routine cardiac surgery have been questioned and the adverse effects of hyperthermia demonstrated. The purpose of the present study was to examine current temperature management and monitoring practices during adult cardiac surgery using CPB in Canada. METHODS: Web-based survey referring to adult cases undergoing cardiac surgery using CPB without the use of deep hypothermic circulatory arrest. Thirty-two questionnaires were completed, representing a 100% response rate. RESULTS: The usual management is to cool patients during CPB at 30 (94%) centers for low-risk (isolated primary CABG) cases and at 31 (97%) centers for high-risk (all other) cases. The average nadir temperature at the target site achieved on CPB is 34°C (range 28°C - 36°C). At 26 (81%) centers, patients are typically rewarmed to a target temperature between 36°C and 37°C before separation from CPB. Only 6 (19%) centers reported that thermistors and coupled devices used to monitor blood temperature are checked for accuracy or calibrated according to the product operating directive's schedule or more often. CONCLUSIONS: Contemporary management of adult cardiac surgery under CPB still involves induction of mild to moderate systemic hypothermia. Significant practice variation exists across the country with respect to target temperatures for cooling and rewarming, as well as the site for temperature monitoring. This probably reflects the lack of definitive evidence. There is a need for well-conducted clinical trials to provide more robust evidence regarding temperature management.

Gender differences in the long-term outcomes after valve replacement surgery.

OBJECTIVE: To compare the long-term outcomes in women and men after valve replacement surgery. DESIGN: Observational study. SETTING: Postoperative aortic valve replacement (AVR) or mitral valve replacement (MVR). PATIENTS: 3118 patients (1261 women, 1857 men) who underwent AVR or MVR between 1976 and 2006 (2255 AVR, 863 MVR), with mean follow-up of 5.6 (4.5) years. MAIN OUTCOME MEASURES: The independent effect of gender on the risk of long-term complications (reoperation, stroke and death) after valve replacement surgery using multivariate actuarial methods. RESULTS: After implantation of an aortic valve bioprosthesis, women had a significantly lower rate of reoperation compared to men (comorbidity-adjusted hazard ratio (HR) 0.4; 95% confidence intervals (CI) 0.2 to 0.9). In contrast, if an aortic mechanical prosthesis had been implanted, women were more at risk for late stroke compared to men (HR 1.7; CI 1.1 to 2.7). After adjustment for age and co-morbidities, women had significantly better long-term survival compared to men after bioprosthetic AVR (HR 0.5; CI 0.3 to 0.6), but there was no survival difference between genders after mechanical AVR. Trends existed towards better survival for women after bioprosthetic MVR (HR 0.6; CI 0.4 to 1.0) and mechanical MVR (HR 0.8; CI 0.5 to 1.1). CONCLUSION: The long-term outcomes after valve replacement surgery differ between women and men. Although women have more late strokes after valve replacement, they undergo fewer reoperations and have better overall long-term survival compared to men.

A decision aid for autologous pre-donation in cardiac surgery--a randomized trial.

OBJECTIVES: The objective of this randomized, controlled study was to determine the usefulness of a decision aid on pre-donation of autologous blood before elective open heart surgery. METHODS: The decision aid (DA) group received a tape and booklet which described the options for peri-operative transfusion in detail. The no decision aid (NDA) group received information usually given to patients about autologous donation. RESULTS: A total of 120 patients were randomized. The DA group rated themselves better prepared for decision making and showed significant improvements in knowledge (p = 0.001) and realistic risk perceptions (p = 0.001). In both groups there was an increase in the proportion of patients choosing allogeneic blood between baseline and follow-up (p = 0.001). Patients in the DA group were significantly more satisfied with the amount of information they received, how they were treated and with the decision they made, than patients in the NDA group. CONCLUSION: The decision aid is useful in preparing patients for decision making. PRACTICE IMPLICATIONS: The next stage is to explore strategies to make it available to all appropriate patients.

Delayed thrombin generation is not associated with fibrinopeptide formation during prolonged cardiopulmonary bypass with hirudin anticoagulation.

Patients with heparin-induced thrombocytopenia urgently requiring surgery with cardiopulmonary bypass (CPB) present a unique management challenge that must be addressed by the use of alternative anticoagulants. Although clinical success with the direct thrombin inhibitor hirudin has been reported, there is sparse information in the literature supporting the efficacy of this drug as an anti-thrombotic to prevent fibrin formation during CPB. In this report, we describe the efficacy of this drug to prevent thrombin-mediated fibrin formation during CPB.

Are we doing everything we can to conserve blood during bypass? A national survey.

INTRODUCTION: Despite major advances in biomaterial research and blood conservation, bleeding is still a common complication after cardiopulmonary bypass and cardiac surgery remains a major consumer of blood products. Although the underlying mechanisms for these effects are not fully established, two proposed major etiologies are the hemodilution associated with the use of the heart-lung machine and the impact of reinfusion of shed cardiotomy blood. Therapeutic strategies that primarily encompass the use of devices or technologies to overcome these effects may result in improved clinical outcomes. OBJECTIVE: To determine the extent to which 1) lipid/leukocyte filtration and centrifugal processing of cardiotomy blood, and 2) modified ultrafiltration (MUF) are currently applied in adult cardiac surgery in Canada. METHODS: A questionnaire was mailed to the chief perfusionist at all adult cardiac surgical centers in Canada, addressing details regarding the frequency of use of cardiotomy blood processing and MUF. RESULTS: All questionnaires (36, 100%) were completed and returned. With regards to cardiotomy blood management, in 21 centers (58%), no specific processing steps were utilized exclusive of the integrated cardiotomy reservoir filter. Of the remaining centers, two (6%) reported using lipid/leukocyte filtration and 15 (42%) reported washing their cardiotomy blood. Three centers (8%) reported using MUF at the end of CPB. CONCLUSIONS: Despite growing concern about the potential detrimental effects of cardiotomy blood, few centers in Canada routinely manage this blood with additional filtration and/or centrifugal processing prior to reinfusion. Similarly, MUF, demonstrated to be effective in the pediatric population, has not seen popular application in adult cardiac surgical practice.

The inflammatory response to cardiopulmonary bypass: a therapeutic overview.

The demographic of cardiac surgery patients continues to evolve to include older, sicker candidates, all the while maintaining an expectation of excellent outcomes. These latter results can only be achieved by the parallel advancement and re-examination of the technology of cardiopulmonary bypass (CPB); the key tool used daily by surgical teams worldwide. In this review, we will provide an overview of integrated therapeutic strategies that can be utilized to minimize the complex and myriad changes related to inflammation after CPB with the understanding that this may abrogate the detrimental end-organ and systemic effects of blood activation. Therapeutic strategies specifically related to the technology can be classified into those targeting biomaterial dependent or independent processes. The former can be addressed by the utilization of currently available biocompatible surfaces such as with heparin-coated circuits, phosphorylcholine-coated circuits ('biomembrane mimicry') and circuits composed of copolymers containing surface-modifying additives. The most important strategies related to biomaterial independent activation include the modification of techniques related to cardiotomy blood management and blood filtration. Finally, all of these strategies must be integrated and tailored with complementary pharmacologic agents such as aprotinin and steroids to optimize anti-inflammatory synergism. Only if we are armed with a comprehensive knowledge of the molecular and cellular basis for these strategies will we be able to continue to evolve our treatment in parallel with our patients to achieve these goals.

Platelet-rich-plasmapheresis for minimising peri-operative allogeneic blood transfusion.

BACKGROUND: Concerns regarding the safety of transfused blood have generated considerable enthusiasm for the use of technologies intended to reduce the use of allogeneic blood (blood from an unrelated donor). Platelet-rich plasmapheresis (PRP) offers an alternative approach to blood conservation. OBJECTIVES: To examine the evidence for the efficacy of PRP in reducing peri-operative allogeneic red blood cell (RBC) transfusion, and the evidence for any effect on clinical outcomes such as mortality and re-operation rates. SEARCH STRATEGY: Studies were identified by: computer searches of MEDLINE, EMBASE, Current Contents, and the Cochrane Library (to June 2001). These searches were supplemented by checking the reference lists of published articles, reports, and reviews. SELECTION CRITERIA: Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to PRP, or to a control group who did not receive the intervention. DATA COLLECTION AND ANALYSIS: Main outcomes measured were: the number of patients receiving an allogeneic RBC transfusion, and the amount of RBC transfused. Trial quality was assessed using criteria proposed by Schulz et al. (Schulz 1995) and Jadad et al. (Jadad 1996). MAIN RESULTS: Nineteen trials of PRP were identified that reported data for the number of patients exposed to allogeneic RBC transfusion. These trials evaluated a total of 1452 patients. The pooled relative risk (RR) of exposure to allogeneic blood transfusion in those patients randomised to PRP was 0.71 (95%CI: 0.56, 0.90), equating to a relative risk reduction (RRR) of 29%; the average absolute risk reduction (ARR) was 19% (RD = -0.19: 95%CI: -0.29, -0.09). On average, PRP did not significantly reduce the total volume of RBC transfused (weighted mean difference [WMD] = -0.69: 95%CI: -1.93, 0.56 units). Substantial statistical heterogeneity was observed (p < 0.001). Trials provided inadequate data regarding the impact of PRP on morbidity, mortality, and hospital length of stay. The majority of trials were small and of poor methodological quality. REVIEWER'S CONCLUSIONS: Although the results suggest that PRP is effective in reducing allogeneic RBC transfusion in adult patients undergoing elective surgery, there was considerable heterogeneity in treatment effects and the trials were of poor methodological quality. As the majority of trials were unblinded, transfusion practices may have been influenced by knowledge of the patient's allocation status, potentially exaggerating the true magnitude of the beneficial effect of PRP. The available studies provided inadequate data for firm conclusions to be drawn regarding the impact of PRP on clinically important endpoints.

Cardiopulmonary bypass technology transfer: musings of a cardiac surgeon.

The development of cardiopulmonary bypass (CPB) has been one of the greatest technical advancements in cardiovascular medicine. With heparin anticoagulation, this device can safely replace the circulatory and gas-exchanging functions of the heart and lung, facilitating complex cardiac operations. Limitations still exist however, related to blood reactions at the biomaterial surface, such as cell activation, inflammation and low-grade thrombosis. In this brief review, the thought processes which paralleled the development of CPB biocompatible surfaces such as heparin-coating, will be explored, as well as current theories on the suspected mechanisms by which heparin-coated surfaces act as an anti-inflammatory device during CPB. Results with new surfaces for CPB designed to capitalize on superior protein adsorption properties, such as surface modifying additive (SMA) and poly (2-methoxyethylacrylate) (PMEA), will also be described. Finally, the significance of biomaterial-independent blood activation will be discussed, emphasizing the current need to develop strategies utilizing optimal biomaterials, modified surgical technique and pharmacologic therapy to minimize the systemic complications of CPB.

Is tranexamic acid safe in patients undergoing coronary endarterectomy?

BACKGROUND: Patients undergoing coronary endarterectomy during coronary artery bypass grafting (CABG) are at increased risk of perioperative myocardial infarction due to coronary intimal disruption. Data assessing the safety of the antifibrinolytic drug tranexamic acid (TA) in patients undergoing this procedure are lacking. METHODS: From September 1997 to December 1999, 221 patients underwent nonemergency primary CABG with endarterectomy of the right coronary artery alone in 149, the left anterior descending in 35, or both right and left anterior descending in 27. TA was administered intraoperatively to 87 patients (TA group: average total dose 62 +/- 4.4 mg/kg; range 20 to 109 mg/kg), and was not administered to 134 patients (No TA group). RESULTS: The patient characteristics of the 2 groups were similar. In-hospital mortality consisted of 2 patients in the TA group and 4 patients in the No TA group. Perioperative myocardial infarction rates were 2% and 5% in the TA and No TA groups, respectively (p = 0.49). The relative risk for any type of perioperative cardiac ischemic event in the TA group versus the No TA group was 0.77 (95% CI; 0.4, 1.2). Patients in the TA group had a significant reduction in postoperative chest tube drainage (685 versus 894 mL in the TA versus No TA groups, respectively) and in the use of fresh-frozen plasma (p = 0.03). CONCLUSIONS: These results suggest that the clinical effectiveness of tranexamic acid in reducing postoperative blood loss in patients undergoing coronary endarterectomy is not associated with a higher incidence of myocardial ischemia-related complications.

Non-pharmacological strategies for blood conservation in cardiac surgery.

PURPOSE: Of all surgical specialties, cardiac operations are most often associated with coagulopathy, blood loss, and the need for transfusions. This not only represents a major burden on blood procurement and banking organizations at all levels, but also constitutes a risk for each patient receiving allogeneic blood products. This paper reviews current non-pharmacological strategies aimed at decreasing blood use in patients undergoing cardiac surgery. SOURCE: The literature pertaining to each blood conservation strategy was searched, reviewed, and appraised. Meta- analyses were also consulted and their results complemented with subsequent reports when available. PRINCIPAL FINDINGS: Preoperative autologous donation programs are effective in decreasing allogeneic transfusions, but are costly and applicable to elective patients only. Off-pump revascularization strategies also appear to decrease transfusion requirements in suitable patients. The effectiveness of acute normovolemic hemodilution, retrograde autologous priming, small volume cardiopulmonary bypass circuits, platelet-rich plasmapheresis, alternative heparin strategies, and postoperative cell salvage are more difficult to appraise as a high proportion of available studies suffer from lack of transfusion guidelines or the absence of blinding. Biological glues, surgical adhesives, and postoperative increases in positive end-expiratory pressure (PEEP) have no demonstrated efficacy. CONCLUSION: The applicability or effectiveness of many of these modalities remains controversial and more studies are needed before they may be employed routinely in cardiac surgical patients. The judicious use of rational transfusion guidelines may still be the simplest and most cost-effective means of blood conservation today.

Feasibility of blinding in a randomized controlled trial comparing preoperative autologous blood donation and acute normovolemic hemodilution in adult cardiac surgery.

BACKGROUND: Acute normovolemic hemodilution and preoperative autologous donation have been shown to be effective techniques for decreasing the exposure of patients to allogeneic blood during cardiac surgery. They have not, however, been compared to each other, because of perceived difficulties in blinding in such a clinical study. The feasibility of blinding was tested in a pilot trial. STUDY DESIGN AND METHODS: Ten patients were randomly assigned to undergo preoperative autologous blood donation or acute normovolemic hemodilution during cardiac surgery. Patients were blinded during this process by shielding of the arm and by insertion of an intravenous line in each patient. Every attempt was made to blind the clinical staff during and after surgery. The effectiveness of this blinding was determined by using a questionnaire. RESULTS: In the 10 cases, six patients, four surgeons, and one anesthetist answered, "I do not know," with respect to whether preoperative autologous blood donation had occurred. The remaining people interviewed believed the blinding was unsuccessful. However, correct answers were given by 75 percent of the patients (95% CI, 19-99%), 83 percent of the surgeons (95% CI, 36-99.6%), and 66 percent of the anesthetists (95% CI, 29.9-92.5%). The frequency of correct answers did not differ significantly from the 50 percent expected by chance, but the CIs are wide. CONCLUSIONS: Blinding of patients and all members of the surgical team during both the preoperative donation process and acute normovolemic hemodilution in the operating theater was successful most of the time, as the frequency of correct answers did not differ significantly from the 50 percent expected by chance. However, more accurate estimates of the success of blinding require a study with a larger sample. It is possible that, with a larger series, the physician's ability to determine patient assignment would be significantly better than that by chance alone.

Use of recombinant-hirudin in pulmonary thromboendarterectomy.

A patient with chronic thromboembolic pulmonary hypertension and heparin-induced thrombocytopenia successfully underwent pulmonary thromboendarterectomy with circulatory arrest, using recombinant hirudin as an alternative anticoagulant to heparin. Techniques for administration as well as monitoring of this drug's effects are discussed.

Circuits with surface modifying additive alter the haemodynamic response to cardiopulmonary bypass.

OBJECTIVE: Blood contact with synthetic surfaces during cardiopulmonary bypass (CPB), inevitably results in the activation of a variety of interrelated pathways of inflammation and coagulation that may contribute to postoperative complications in cardiac surgery patients. The objective of this trial was to evaluate clinical events and complement activation related to the use of a novel biomaterial, into which a surface modifying additive had been incorporated into the polymer used to prepare the bypass circuit. METHODS: A prospective, double-blind trial was carried out with 34 patients randomized to surgery, with either a standard circuit or a circuit treated ('tip to tip') with the surface modifying additive. Variables recorded included perioperative haemodynamics, volume replacement, alpha-agonist and inotrope use. Terminal complement complex (SC5b-9) was measured using an ELISA. RESULTS: Upon initiation of bypass, there was a decrease in mean arterial pressure (MAP) in the control group, not seen in the test group (P = 0.0005, ANOVA). There was a decrease in the total volume of replacement fluid given intraoperatively in the test group as compared with the control group (total plus prime; control 5.3 +/- 1.2 L, test 4.4 +/- 1.9 L, P = 0.03, Mann-Whitney test). There was a trend to decreased need for inotrope infusion in the test group after CPB (test 1/17, control 6/17, Fisher exact test; P = 0.085). No difference was seen in the generation of terminal complement complex between the groups either during or after CPB. CONCLUSIONS: The decrease in blood pressure in the control group, upon the initiation of CPB, did not occur in patients undergoing CPB with the circuit prepared with the surface modifying additive. The decrease in blood pressure was likely associated with the increase in total administered fluids intraoperatively (approximately 1 l/patient) and perhaps the trend towards higher use of inotropes in the control patients as opposed to the test patients. These haemodynamic changes did not appear to be related to complement activation early in CPB.

Sternothoracotomy for combined coronary artery bypass grafting and left upper lobectomy in a patient with low-lying tracheostoma.

A 64-year-old man had a low-lying tracheostoma and presented with unstable angina and a mass in the pulmonary left upper lobe. Simultaneous coronary revascularization and resection of the lung neoplasm were completed through a sternothoracotomy (clam-shell) incision. The advantages of this approach include excellent exposure to the mediastinum and the lung fields, and the option of using both internal thoracic arteries for bypass grafting.

Hematologic evaluation of cardiopulmonary bypass circuits prepared with a novel block copolymer.

BACKGROUND: To decrease the complications associated with cardiopulmonary bypass, novel biomaterials have been introduced that may be less thrombogenic than standard synthetic surfaces. METHODS: Thirty-four patients undergoing coronary artery bypass grafting were randomized to bypass using either a control circuit or a circuit prepared "tip-to-tip" with a triblock-copolymer (polycaprolactone-polydimethylsiloxane-polycaprolactone). RESULTS: There was a progressive increase in thrombin generation in the control group during bypass, which was not seen in the test group. The test surface decreased the release of tissue plasminogen activator and plasmin-alpha2-antiplasmin complex formation (p<0.005). There was also an increased platelet count and a decreased platelet activation in the test group, as detected by GMP-140 expression and beta-thromboglobulin release (p = 0.017). There was also significantly more debris that accumulated on the arterial filter in the control group, as confirmed by scanning electron microscopy. CONCLUSIONS: This clinical trial has demonstrated a significant difference in the hematologic effects of the test circuits, with evidence of platelet preservation, decreased fibrinolysis, and decreased thrombin generation. A larger trial would be necessary to establish the clinical relevance of these differences.