A Blinded Randomized Trial Comparing Standard Activated Clotting Time Heparin Management to High Target Active Clotting Time and Individualized Hepcon HMS Heparin Management in Cardiopulmonary Bypass Cardiac Surgical Patients.

PURPOSE: High-dose heparin has been suggested to reduce consumption coagulopathy. MATERIALS AND METHODS: In a randomized, blinded, prospective trial of patients undergoing elective, complex cardiac surgery with cardiopulmonary bypass, patients were randomized to one of three groups: 1) high-dose heparin (HH) receiving an initial heparin dose of 450 u/kg, 2) heparin concentration monitoring (HC) with Hepcon Hemostasis Management System (HMS; Medtronic, Minneapolis, MN, USA) monitoring, or 3) a control group (C) receiving a standard heparin dose of 300 u/kg. Primary outcome measures were blood loss and transfusion requirements. RESULTS: There were 269 patients block randomized based on primary versus redo sternotomy to one of the three groups from August 2001 to August 2003. There was no difference in operative bleeding between the groups. Chest tube drainage did not differ between treatment groups at 8 hours (median [25th percentile, 75th percentile] for control group was 321 [211, 490] compared to 340 [210, 443] and 327 [250, 545], p = 0.998 and p = 0.540, for HH and HC treatment groups, respectively). The percentage of patients receiving transfusion was not different among the groups. CONCLUSION: Higher heparin dosing accomplished by either activated clot time or HC monitoring did not reduce 24-hour intensive care unit blood loss or transfusion requirements.

Use of an autologous blood recovery system during emergency pericardiocentesis in the electrophysiology laboratory.

INTRODUCTION: Emergency pericardiocentesis during electrophysiology procedures is often associated with significant aspiration of pericardial blood, requiring transfusion. We sought to assess the feasibility of urgent use of an autologous blood recovery system in the electrophysiology laboratory to autotransfuse blood aspirated from the pericardium. METHODS AND RESULTS: We retrospectively analyzed Mayo Clinic electrophysiology records for patients who had ablation procedure-related pericardial effusions requiring emergency pericardial drainage during an 8-month period. An autologous blood recovery system was used during pericardiocentesis to separate and clean packed red blood cells from the pericardial aspirate. These cells were returned acutely to the patient intravenously. The procedural safety, aspirated and autotransfused volumes, and efficacy of this approach were evaluated. During the study period, nine patients underwent pericardial drainage with autotransfusion using a cell-salvage instrument during electrophysiology procedures. The mean aspirated volume was 1,078 mL, with a mean autotransfused volume of 390 mL. For four patients, all with aspirated volumes of 1,100 mL or less, autotransfusion alone was sufficient to maintain hemodynamic stability and avoid allogeneic transfusion. One patient required surgical intervention because of ongoing pericardial bleeding. The ablation procedure was completed after aspiration in two patients. No procedural complications related to the use of the cell-salvage system occurred. CONCLUSION: Autologous blood recovery during pericardiocentesis is safe, convenient, and feasible. With early use it may decrease or eliminate the need for allogeneic blood transfusion and, in selected cases, may permit completion of the ablation procedure.

Can N-acetylcysteine reverse the antiplatelet effects of clopidogrel? An in vivo and vitro study.

BACKGROUND: The active metabolite of clopidogrel binds the P2Y12 ADP receptor on the platelet surface via a disulfide bond. N-Acetylcysteine (NAC) is able to reduce disulfide bonds. We postulated that NAC might reverse clopidogrel's effect on platelets. METHODS: Two groups of patients were investigated. Group 1 included 11 patients with stable coronary disease who, after discontinuation of aspirin, received 14 days of clopidogrel, 75 mg/day. Bleeding time and whole-blood platelet aggregometry (with 5 micromol/L ADP) were compared before and after the 14 days. Patients were then treated with 6 g of NAC orally, followed by repeat measurement of bleeding time and aggregometry. In group 2, 14 patients were treated with clopidogrel (300 mg) and aspirin before a percutaneous coronary intervention. Blood was drawn 22 +/- 3 hours later and divided into 2 samples. One was sent immediately for platelet-rich plasma aggregometry (using 5 and 2 micromol/L ADP, collagen, and arachidonic acid as agonists), thromboelastography, and aggregometry using the Plateletworks assay (Helena Laboratories, Beaumont, Tex). The other sample was treated with NAC (500 mg/L), after which these same platelet function tests were performed. RESULTS: In group 1, NAC therapy did not significantly change the bleeding time or results of aggregometry. In group 2, neither aggregometry nor the Plateletworks assay suggested reversal of inhibition by NAC. CONCLUSIONS: These studies reveal that a large dose of NAC does not reduce inhibition of platelet aggregation by clopidogrel in vitro or in vivo.

Frozen preoperative autologous blood donation for heart transplantation at the Mayo Clinic from 1988 to 1999.

BACKGROUND: Preoperative autologous blood donation (PABD) has been used to reduce the need for allogeneic RBC transfusion, decreasing risk and conserving supply. A frozen PABD program for heart transplant patients was instituted at the Mayo Clinic in 1988, but participation has steadily declined. The aims of this study were to determine how the availability of PABD influenced the transfusion RBC components, whether the availability of PABD reduced exposure to allogeneic RBC components, and the costs of providing PABD units. STUDY DESIGN AND METHODS: A retrospective review of all heart transplant cases from 1988 to 1999 was performed (n = 141). Data on collection and transfusion practices were compared for patients with (n = 88, 62%) and without PABD (n = 53, 38%). RESULTS: Total RBC transfusion requirements did not differ between the groups. Patients with frozen PABD received fewer allogeneic units, but they also had less blood salvaged and reinfused. Twenty patients (23%) completely avoided exposure to allogeneic RBCs in the PABD group versus three patients (6%) in the group without PABD. Although patients in the PABD group successfully donated a total of 423 units, 41 percent were discarded. Over 11 years, the need for 251 units of allogeneic RBCs was avoided ($27,610), but $283,500 was spent to have the frozen PABD units available. CONCLUSION: PABD can be performed for heart transplantation, but it is expensive.