Evidence of Trypanosoma cruzi infection (Chagas' disease) among patients undergoing cardiac surgery.

BACKGROUND: Trypanosoma cruzi, the agent of Chagas' heart disease, is transmitted by triatomine insects and by blood transfusion. The emigration of several million people from T cruzi-endemic countries to the United States has raised concerns regarding a possible increase in cases of Chagas' heart disease here, as well as an increased risk of transfusion-transmitted T cruzi. To investigate these 2 possible outcomes, we tested a repository of blood specimens from multiply transfused cardiac surgery patients for antibodies to T cruzi. METHODS AND RESULTS: Postoperative blood specimens from 11 430 cardiac surgery patients were tested by enzyme immunoassay, and if repeat-reactive, were confirmed by radioimmunoprecipitation. Six postoperative specimens (0.05%) were confirmed positive. Corresponding preoperative specimens, available for 4 of these patients, were also positive. The other 2 patients had undergone heart transplantations. Tissue samples from their excised hearts were tested for T cruzi by polymerase chain reaction and were positive. Despite the fact that several of these 6 patients had histories and clinical findings suggestive of Chagas' disease, none of them were diagnosed with or tested for it. Patient demographics showed that 5 of 6 positive patients were Hispanic, and overall, 2. 7% of Hispanic patients in the repository were positive. CONCLUSIONS: No evidence for transfusion-transmitted T cruzi was found. All 6 seropositive patients apparently were infected with T cruzi before surgery; however, a diagnosis of Chagas' disease was not known or even considered in any of these patients. Indeed, Chagas' disease may be an underdiagnosed cause of cardiac disease in the United States, particularly among patients born in countries in which T cruzi is endemic.

Impact of distal aortic and visceral perfusion on liver function during thoracoabdominal and descending thoracic aortic repair.

PURPOSE: We examined the impact of distal aortic and visceral perfusion on liver function during thoracoabdominal and descending thoracic aortic repair. METHODS: Between January 1991 and July 1996, 367 patients underwent thoracoabdominal and descending thoracic aortic repair. Baseline and postoperative total bilirubin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, fibrinogen, prothrombin time (PT), and partial thromboplastin time (PTT) were measured for 286 patients. We examined the impact of distal aortic and direct visceral perfusion on liver function-related clinical laboratory values. Univariate and multivariate statistical methods for categorical and continuous variables were used. RESULTS: In categorical analysis, type II thoracoabdominal aortic aneurysm, history of hepatitis, and emergency presentation had a statistically significant multivariate association with abnormal laboratory values. In continuous-distributed multivariate data analysis, type II thoracoabdominal aortic aneurysm and visceral perfusion were statistically significant predictors of postoperative alkaline phosphatase, PT, and PTT. Type II aneurysms increased postoperative liver function-related laboratory values significantly above other aneurysm types (alkaline phosphatase, +114 IU, p < 0.0001; PT, +1.99 seconds, p < 0.02; PTT, +6.7 seconds, p < 0.03). Visceral perfusion was associated with a concomitant decrease (alkaline phosphatase, -101.2 IU, p < 0.0001; PT, -1.8 seconds, p < 0.07; PTT, -5.6 seconds, p < 0.02). CONCLUSIONS: Visceral perfusion negates the rise in postoperative liver function-related clinical laboratory values associated with type II thoracoabdominal aortic aneurysm repair.

Radical retropubic prostatectomy: limited benefit of autologous blood donation.

PURPOSE: We determine whether autologous blood donation significantly decreases the need for homologous transfusions after radical prostatectomy. MATERIALS AND METHODS: The effects of estimated blood loss and autologous donation on the rate of homologous transfusions were analyzed in 3 groups of 100 consecutive patients treated between 1983 and 1992. RESULTS: Overall, donors were less likely than nondonors to receive homologous blood. As median estimated blood loss decreased from 1,200 to 800 cc from groups 1 to 3 (p < 0.05), the incidence of nondonors requiring homologous blood decreased from 62 to 11% and that of autologous units transfused decreased from 96 to 19%. CONCLUSIONS: With decreasing blood loss, safe but stringent criteria for transfusion and improved safety of the blood supply, autologous donation is an inefficient method to lower the slight risk of complications following homologous transfusion during radical prostatectomy.

Retrograde cerebral perfusion during profound hypothermia and circulatory arrest in pigs.

The purpose of this study was to evaluate the use of retrograde cerebral perfusion via the superior vena cava during profound hypothermia and circulatory arrest (CA) in pigs. In three groups of 5 pigs each, group A (control) underwent cardiopulmonary bypass and normothermic CA for 1 hour, group B underwent cardiopulmonary bypass, profound hypothermia, and CA (15 degrees C nasopharyngeal) for 1 hour, and group C underwent the same procedure as group B plus retrograde cerebral perfusion. In group A none awoke. In group B, 2 of 5 did not awake and 3 of 5 awoke unable to stand, 2 with perceptive hind limb movement and 1 moving all extremities. In group C all awoke, 4 of 5 able to stand and 1 of 5 unable to stand but moving all limbs. In neurologic evaluation group B had significantly lower Tarlov scores than group C (p = 0.0090). Group B mean wake-up time, plus or minus standard error of the mean, was 124.6 +/- 4.6 minutes versus 29.2 +/- 5.1 in group C (p = 0.0090). In group B late phase CA cerebral blood flow dropped 30.9% +/- 4.8%, but in group C it rose 24.7% +/- 9.3% (p = 0.0007, pooled variance t test, two-tailed). In group B late phase CA brain oxygenation decreased 46.0% +/- 13.9% but it increased 26.1% +/- 5.4% in group C (p = 0.0013). This difference was reduced somewhat during rewarming (B, -21.2% +/- 14.9%; C, 16.4% +/- 4.7%; p = 0.043). Group B rewarming jugular venous O2 saturation was 30.8% +/- 2.5% versus 56.0% +/- 4.4% in group C (p = 0.0011). We conclude that in pigs retrograde cerebral perfusion combined with profound hypothermia during CA significantly reduces neurologic dysfunction, providing superior brain protection.

Limiting homologous blood exposure.

Successful limitation of homologous blood transfusion may necessitate multiple strategies and advance planning. Preoperative and intraoperative autologous blood collection may have to be supplemented with hemostatic pharmacologic agents. The use of cytokines is increasing. More efficient use of directed donors can have an important role in blood use. As these expensive and time-consuming techniques become available, a major challenge will be to determine which patients may benefit from or really need them.

Transmission of retroviruses from seronegative donors by transfusion during cardiac surgery. A multicenter study of HIV-1 and HTLV-I/II infections.

OBJECTIVE: To evaluate the effectiveness of serologic testing of blood donors for human immunodeficiency virus type 1 (HIV-1) and human T-cell lymphotropic virus types I and II (HTLV-I/II) infections and to estimate the risk for transmission of HIV-1 and HTLV-I/II by transfusion of seronegative blood from screened donors. DESIGN: A prospective multicenter cohort study of cardiac surgery patients who received multiple transfusions between 1985 and 1991. SETTING: Cardiac surgery services of three large tertiary care hospitals. PATIENTS: The study included 11,532 patients in three hospitals who had cardiovascular surgery. MEASUREMENTS: Incident HIV-1 and HTLV-I or HTLV-II infection. RESULTS: We detected two new HIV-1 infections among patients transfused with 120,312 units of blood components from seronegative donors. In each case a donor was detected on follow-up who had seroconverted since the donation. The HIV-1 infection rate was 0.0017% with an upper limit of the 95% CI of 0.0053%. Before donor screening for HTLV-I, transfusion of 51,026 units resulted in two HTLV-I infections (0.0039%) and four HTLV-II infections (0.0078%). After HTLV-I screening was instituted, one recipient was infected with HTLV-II among participants exposed to 69,272 units, a rate of 0.0014%. A corresponding HTLV-I/II-infected donor was found for this patient. CONCLUSION: Serologic screening of donors for antibodies to HIV-1 and HTLV-I coupled with exclusion of donors from groups having a relatively high risk for infection has led to a low incidence of transfusion-transmitted HIV-1 and HTLV-I/II infection in the United States. A small risk remains, however, despite these measures. We estimate the residual risk for HIV-1 and HTLV-II infection from transfusion of screened blood during the time of this study to be about 1 in 60,000 units.

The declining risk of post-transfusion hepatitis C virus infection.

BACKGROUND: The most common serious complication of blood transfusion is post-transfusion hepatitis from the hepatitis C virus (HCV). Blood banks now screen blood donors for surrogate markers of non-A, non-B hepatitis and antibodies to HCV, but the current risk of post-transfusion hepatitis C is unknown. METHODS: From 1985 through 1991, blood samples and medical information were obtained prospectively from patients before and at least six months after cardiac surgery. The stored serum samples were tested for antibodies to HCV by enzyme immunoassay, and by recombinant immunoblotting if positive. RESULTS: Of the 912 patients who received transfusions before donors were screened for surrogate markers, 35 seroconverted to HCV, for a risk of 3.84 percent per patient (0.45 percent per unit transfused). For the 976 patients who received transfusions after October 1986 with blood screened for surrogate markers, the risk of seroconversion was 1.54 percent per patient (0.19 percent per unit). For the 522 patients receiving transfusions since the addition in May 1990 of screening for antibodies to HCV, the risk was 0.57 percent per patient (0.03 percent per unit). The trend toward decreasing risk with increasingly stringent screening of donors was statistically significant (P less than 0.001). After we controlled for the method of donor screening, the risk of seroconversion was strongly associated (P less than 0.001) with the volume of blood transfused, but not with the use of particular blood components. CONCLUSIONS: The incidence of post-transfusion hepatitis C has decreased markedly since the implementation of donor screening for surrogate markers and antibodies to HCV. The current risk of post-transfusion hepatitis is about 3 per 10,000 units transfused.

Impact of whole blood usage in massive transfusion.

A retrospective survey comparing blood and component usage during thoracoabdominal aortic reconstruction between patients receiving whole blood vs packed red cells was conducted. Volume of salvaged blood, usage of homologous blood components, and total homologous exposures were compared between eight patients who received only packed red blood cells and four patients who received whole blood for replacement of surgical losses, using a chi-square test for comparison. All variables demonstrated a decline among patients who received whole blood. The declines in homologous blood and plasma usage were statistically significant (P less than .05). The decline in platelet usage did not reach statistical significance. The decline in total homologous exposures approached statistical significance (P less than .1). The data suggest that use of whole blood for expected massive transfusion may reduce total blood-component requirements and total homologous exposures.

Transfusion and coagulation: an overview and recent advances in practice modalities. Part II: Pharmacologic adjuncts, cell salvage mechanisms, alternatives in blood donation.

Increasing public awareness of the risks associated with the transfusion of blood products has encouraged the development of alternatives to the use of homologous blood. Pharmacologic agents, cell salvage, and directed donations are three such mechanisms being utilized with greater frequency for blood and component therapy. At present, only three drugs are available for clinical use: DDAVP, epsilon-aminocaproic acid, and tranexamic acid. Cell salvage is available in two system types. Salvage of whole blood in passive collection systems is simplest to use and returns more coagulation factors, but yields a larger volume with a lower hematocrit. Whole blood salvage with subsequent washing and resuspension in normal saline returns only red cells in saline with the majority of coagulation factors removed. The quality of red cells in each system remains relatively constant and the decision regarding which system to employ should be based on the nature of the surgical procedure and the anticipated blood loss. The development of directed donation programs, including autologous predonation and directed homologous donation, permits a reduction in the frequency and total number of units of homologous volunteer blood administered. Directed blood donation provides an additional source of donated blood, but is not demonstrably safer than the volunteer homologous pool, and in fact, may even be less safe. Given the increased complexity of maintaining a designated donor program, these issues of safety play an important role in the ability to maintain operation of large scale directed donation programs.

Use of pre-operatively obtained platelets and plasma in patients undergoing cardiopulmonary bypass.

Thirty-seven patients requiring cardiopulmonary bypass were prospectively studied and assigned to plateletpheresis or control groups in a non-randomized, non-blinded fashion according to apheresis exclusion criteria and our ability to perform apheresis within 24 hours of surgery. Patients were grouped by potential for hemostatic abnormalities following a risk point factor assignment established for this study. The study indicated improvement of hemostasis with autologous platelets and plasma as demonstrated by clinical and laboratory parameters and by overall blood component utilization. We conclude that pre-operative plateletpheresis in this patient population is feasible, safe, and effective.

Blood salvage for cardiovascular surgery.

Intraoperative blood salvage produces safe and clinically effective red cells. Intraoperative salvage for cardiovascular surgery procedures can be expected to cause a substantial reduction in the use of homologous red cells in patients requiring redo operations, and repair of complex aortic aneurysms. The procedure per se will have very little impact on the use of other blood components such as platelets or plasma. For carefully selected patients, autologous perioperative or intraoperative collection of these components should also be considered. The primary risks of intraoperative blood transfusion include washout of clotting proteins and platelets, infusion of undesirable constituents (such as antibiotics and haemostatic agents added during the surgical procedure) and air embolism. Intraoperative autologous transfusion is only one part of an effective programme to minimize homologous transfusion. Equally important is the use of preoperatively donated blood, the use of effective and safe pharmacological agents to enhance haemostasis and haematopoiesis, a conservative approach that allows only the transfusion of blood components absolutely necessary, and, when possible, the elimination of anticoagulant and antiplatelet therapy several days prior to the cardiovascular surgical procedure.

Transmission of retroviruses by transfusion of screened blood in patients undergoing cardiac surgery.

We determined the rates of seroconversion to human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus Type I (HTLV-I) in a cohort of patients receiving transfusions of blood components screened for antibody to HIV-1. Preoperative and postoperative serum samples were collected from 4163 adults undergoing cardiac surgery who received 36,282 transfusions of blood components. The postoperative samples from all patients were tested for serologic evidence of HIV-1 infection, and those that were positive were compared with the corresponding preoperative samples. One case of HIV-1 transmission by transfusion of screened blood components was identified; two preexisting HIV-1 infections were found. Samples from 2749 patients were tested similarly for serologic evidence of HTLV-I infection; these patients received 20,963 units of blood components. Five new cases and two preexisting cases of HTLV-I infection were detected. The observed risk of HIV-1 transmission by transfusion was 0.003 percent per unit; the risk of HTLV-I transmission was 0.024 percent per unit. We conclude that there is a very small risk of HTLV-I infection from transfused blood products that have been screened for antibodies to HIV-1, but that it is nearly 10-fold higher than the risk of HIV-1 infection.

Cost comparison of intraoperative autologous versus homologous transfusion.

The cost of autologous transfusions using semiautomated instruments in 52 orthopedic cases, 75 coronary artery bypass graft (CABG) cases, and 218 aortic aneurysm cases was compared to the cost of equal amounts of homologous blood. While none of the orthopedic cases reached cost equivalence (median cost deficit per case, +97), 31 percent of the CABG cases (median cost deficit per case, +61) and 56 percent of the thoracic aortic aneurysm cases (mean cost surplus per case, +30) did so. In most cases, the major orthopedic and CABG procedures do not reach cost equivalence and might be served better by other means of autologous blood recovery. The more expensive semicontinuous flow devices are more cost-effective for higher-yield cases, such as major aortic aneurysm procedures.

Activation of the complement system by recombinant tissue plasminogen activator.

Recent trials have shown that recombinant tissue plasminogen activator (rt-PA) is an effective thrombolytic agent in patients with acute myocardial infarction. Because rt-PA converts plasminogen to plasmin, which is known to activate complement in vitro, we tested the hypothesis that rt-PA can induce in vivo activation of complement. Studies were performed in 12 patients with acute myocardial infarction. Six control patients had patent coronary arteries and did not receive rt-PA; these patients had normal values of the components of the complement system C4a (409 +/- 111 ng/ml) and C5a (8.8 +/- 1.8 ng/ml) with a slight elevation of C3a (204 +/- 6.6 ng/ml) in samples collected before coronary arteriography (253 +/- 25 minutes after onset of pain). After coronary arteriography, there was a slight decrease in the values of C4a (224 +/- 37 ng/ml), C5a (7.3 +/- 1.3 ng/ml) and C3a (164 +/- 35 ng/ml). The remaining six patients had complete coronary occlusion and received rt-PA (80 to 150 mg intravenously). In this treated group, before coronary arteriography the values of C4a (406 +/- 51.6 ng/ml) and C5a (8.1 +/- 1.9 ng/ml) were normal, and those of C3a were slightly elevated (250 +/- 76 ng/ml). All complement values obtained before rt-PA were similar to those in the untreated group. However, after administration of rt-PA (but before any angiographically detectable reperfusion), there was a striking increase in C4a (2,265 +/- 480 ng/ml; p less than 0.01), C3a (600 +/- 89 ng/ml; p less than 0.05) and C5a (30.0 +/- 4.5 ng/ml; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of profound hypothermia on leukocytes and platelets.

Seventeen patients who underwent aortic arch replacement were subjected to profound hypothermia and circulatory arrest. At maximum cooling, platelet count dropped from 184 +/- 122 to 37 +/- 30 thousand per microliter, and the total leukocytic count fell from 6.27 +/- 4.0 to 1.47 +/- 0.6 thousand per microliter. The thrombocytopenia was partially reversed with rewarming. The total white cell count consistently returned to precooling values or higher (10.5 +/- 4.0). The mechanism for this cold induced phenomenon is not well understood.

Heparin monitoring during cardiopulmonary bypass.

Three procedures have been compared for monitoring heparin in patients undergoing cardiopulmonary bypass: (1) activated clotting time (ACT) (2) protamine titration, and (3) fluorometric substrate assay. The ACT monitors the degree of anticoagulation. It is easy to perform and is relatively inexpensive, however, it does not correlate well with heparin levels and may not accurately predict the protamine dose for neutralization of heparin at the completion of bypass. A protamine titration assay or an assay using a thrombin-sensitive fluorometric substrate measures the heparin level and calculates the protamine requirement at the completion of surgery; however, these assays do not indicate the degree of anticoagulation. The fluorometric assay is the less expensive of the two assay measuring heparin, but it requires an experienced technologist to perform the test.

Fatal hepatoadrenal necrosis in the neonate associated with echovirus types 11 and 12 presenting as a surgical emergency.

Two neonates presented to our service with suspected intraabdominal surgical emergencies. Both subsequently were found to have hepatoadrenal necrosis due to overwhelming echoviral infection. Echovirus types 11 and 12 were isolated postmortem. The latter virus has not been associated previously with fulminant neonatal illness.