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Aprotinin, a potent antifibrinolytic drug, reduces the proportion of adults who receive blood transfusions during cardiac surgery, although the effect in children remains unclear. We performed a systematic review of the literature to identify all English language, randomized controlled trials of aprotinin involving children undergoing corrective or palliative cardiac surgery with cardiopulmonary bypass. All studies were assessed for methodological quality, and sources of heterogeneity were examined. We measured the effect of aprotinin on the proportion of children transfused, the volume of blood transfused, and the volume of chest tube drainage. Twelve trials enrolling 626 eligible children met the inclusion criteria. Aprotinin reduced the proportion of children who received red blood cell or whole blood transfusions during cardiac surgery by 33% (relative risk = 0.67; 95% confidence interval, 0.51 to 0.89). Aprotinin did not have a significant effect on the volume of blood transfused or on the amount of postoperative chest tube drainage. Most of the studies were of poor methodological quality and predefined transfusion triggers were infrequently used. Overall, aprotinin reduced the proportion of children who received blood transfusion during cardiac surgery with cardiopulmonary bypass. Further high-quality trials with clinically important outcomes may be warranted before aprotinin can be routinely recommended in this population.

Objective: To compare a restrictive red blood cell transfusion strategy with a more liberal strategy in volume-resuscitated critically ill patients with cardiovascular disease., Setting: Twenty-two academic and three community critical care units across Canada., Study Design: Randomized controlled clinical trial., Study Population: Three hundred fifty-seven critically ill patients with cardiovascular diseases from the Transfusion Requirements in Critical Care trial who had a hemoglobin concentration of <90 g/L within 72 hrs of admission to the intensive care unit., Interventions: Patients were randomized to a restrictive strategy to receive allogeneic red blood cell transfusions at a hemoglobin concentration of 70 g/L (and maintained between 70 and 90 g/L) or a liberal strategy to receive red blood cells at 100 g/L (and maintained between 100 and 120 g/L)., Results: Baseline characteristics in the restrictive (n = 160) and the liberal group (n = 197) were comparable, except for the use of cardiac and anesthetic drugs (p <.02). Average hemoglobin concentrations (85 +/- 6.2 vs. 103 +/- 6.7 g/L; p <.01) and red blood cell units transfused (2.4 +/- 4.1 vs. 5.2 +/- 5.0 red blood cell units; p <.01) were significantly lower in the restrictive compared with the liberal group. Overall, all mortality rates were similar in both study groups, including 30-day (23% vs. 23%; p = 1.00), 60-day, hospital, and intensive care unit rates. Changes in multiple organ dysfunction from baseline scores were significantly less in the restrictive transfusion group overall (0.2 +/- 4.2 vs. 1.3 +/- 4.4; p =.02). In the 257 patients with severe ischemic heart disease, there were no statistically significant differences in all survival measures, but this is the only subgroup where the restrictive group had lower but nonsignificant absolute survival rates compared with the patients in the liberal group., Conclusion: A restrictive red blood cell transfusion strategy generally appears to be safe in most critically ill patients with cardiovascular disease, with the possible exception of patients with acute myocardial infarcts and unstable angina.

The ability of the rabbit aorta intima-media (IM) layer to adsorb certain plasma proteins was measured for up to 20 months after a deendothelializing injury in vivo. Purified radioiodinated rabbit fibrinogen, antithrombin, or prothrombin was injected intravenously into either uninjured or sham-injured rabbits (controls) or rabbits at various times (5 minutes to 20 months) after a balloon-catheter injury to the aorta. After a 10-minute circulation time, a blood sample was taken, and the rabbit was exsanguinated rapidly (via a carotid cannula) and the aorta excised. Uptake of each radiolabeled protein was measured as bound radioactivity per square centimeter of platelet- or endothelium-free aorta IM and was compared with the radioactivity (ergo concentration) in blood at exsanguination. Fibrinogen adsorption by the IM was maximal at 5 minutes after injury (10.9 +/- 2.3 pmol/cm2 IM) and declined slowly to 4 to 6 pmol/cm2 at 12 months (controls: 0.8 +/- 0.1 pmol/cm2). Uptake of prothrombin (3.7 +/- 0.5 pmol/cm2 at 5 minutes) decreased to approximately 2 pmol/cm2 at 12 months (controls: 0.3 pmol/cm2). Antithrombin adsorption by the IM (3.3 +/- 0.4 pmol/cm2 at 5 minutes) paralleled that of prothrombin over 12 months (controls: 0.3 to 0.4 pmol/cm2), the molar ratio ranging from 0.8 to 1.2. At 20 months, the ballooned aorta had a significantly thickened intima and was approximately 90% reendothelialized. Injection of horseradish peroxidase (HRP) into rabbits at 1 or 12 months after balloon injury showed clearly that HRP activity was present throughout the entire depth of the deendothelialized, but not the reendothelialized, thickened intima. These results may indicate that an elevated turnover of hemostatic proteins continues within the deendothelialized intima after injury, conceivably until reendothelialization is complete.

Balb/c (H-2d) mice were transfused weekly with 0.1 ml of whole blood from C3H (H-2k) mice. One week after 3 blood transfusions (BT), the mice were bled and the sera collected and pooled. The 3BT serum was absorbed twice with C3H lymphocytes and IgG isolated by ion-exchange chromatography. Balb/c anti-C3H, Balb/c anti-Balb/c, and Balb/c anti-SJL (H-2s) lymphocytes were generated in the mixed lymphocyte cultures and metabolically labeled with 35S-methionine. Cell lysates were prepared from labeled lymphocytes and precleared by absorption with normal mouse serum. Immunoprecipitation was carried out by 3BT-IgG and NMS-IgG. 3BT-IgG specifically precipitated 7 molecules (30K, 60K, 72K, 86K, 92K, 97K, 145K) from Balb/c anti-C3H lymphocytes. In contrast, 3BT-IgG did not precipitate these molecules from Balb/c anti-Balb/c or from Balb/c anti-SJL lymphocytes. The data suggest that BT induces antibodies directed against the blood donor alloantigen-specific receptors on recipient's T lymphocytes.