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PubMed2006

The NHLBI Clinical Trials Network in transfusion medicine and hemostasis: an overview.

Transfusion Medicine is a broad discipline that affects the health care of patients from many medical disciplines. Despite the large impact of transfusion therapies on the management of patients with a variety of diseases, there are few clinical trials that evaluate the indications or the effectiveness of transfusion therapies. To respond to this need for better clinical data, the National Heart Lung and Blood Institute of the National Institutes of Health established a clinical trials network in Transfusion Medicine and Hemostasis. Following a competitive selection process, 17 university medical centers and a data coordinating center joined together to collaboratively address clinical questions in transfusion medicine and hemostasis. The activities, organization, and scope of the network is described below. Examples of clinical trials currently in the network "pipeline" are briefly summarized as an overview to more detailed presentations given elsewhere in this symposium.

Blood Transfusion↗
PubMedDate not supplied

Hemostasis of tiger prawn Penaeus monodon affected by Vibrio harveyi, extracellular products, and a toxic cysteine protease.

The effects of bacterial cells, extracellular products (ECP) and a purified cysteine protease of Vibrio harveyi on hemostasis and plasma components of tiger prawn (Penaeus monodon) were studied. The clotting ability of the hemolymph withdrawn from moribund prawns pre-injected with the bacteria, ECP, cysteine protease of PBS (control) was observed for 2 h at 25 C. Of these, only the control group was clottable while all the other groups were unclottable. A component of the plasma, previously identified as coagulogen-like protein, was further confirmed to be a coagulogen by the comparison of plasma with serum on non-reduced SDS-PAGE or using rabbit antiserum to the coagulogen-like protein (R alpha coagulogen) to neutralize the clotting ability of normal prawn hemolymph. The coagulogen was reduced in amount in plasma of moribund prawns after injection with the bacteria, ECP or cysteine protease while it apparently disappeared after pre-incubation with the ECP or cysteine protease for 2 h at 25 C compared with normal prawn plasma as observed in crossed immunoelectrophoresis (CIE) gels. The reduction of the amount of coagulogen in plasma of moribund prawns was also evident in CIE gels using R alpha coagulogen. In addition, the apparent disapperance of the coagulogen mentioned above was eventually proven to be due to the change of its migration rate in CIE gels after pre-incubation with ECP or cysteine protease, since the disappeared coagulogen arc (arc 2) (migrated into arc 1) could be visualized by using R alpha coagulogen or by reducing the time for pre-incubation from 2 h to 30 min. Thus, the effects of cysteine protease on plasma coagulogen observed in vitro and in vivo may markedly interfere with hemostasis leading to the occurrence of unclottable hemolymph. These complex events may significantly contribute to the pathogenicity of V. harveyi in the prawn.

Animals↗
PubMed1988

Endothelial cell function in hemostasis and thrombosis.

Endothelial cells play a pivotal role in hemostasis and thrombosis. They produce a myriad of factors either associated with the membrane or released into the blood stream and the subendothelial matrix which are involved in various steps of hemostasis. The endothelial cell function is modulated by a diversified group of biologically active molecules, notably thrombin, vasoactive amines and cytokines. Mechanism and selectivity of the effects of these molecules differ and the difference may have important physiological implications. Most of the information is gathered through experiments performed in cultured endothelial cells. Availability of the cultured cells has greatly facilitated the understanding of endothelial cell biology. In vivo models, however, are still needed to understand how the endothelial cell function is modulated. Furthermore, as the cultured endothelial cells exhibit nor only species differences but also vascular origin difference in behavior and function, these factors should be carefully considered when designing experiments involving the use of cultured endothelial cells.

Animals↗
PubMed1994

Perineal wound management after abdominoperineal rectal excision for carcinoma with unsatisfactory hemostasis or gross septic contamination: primary closure vs. packing. A multicenter, controlled trial. French Association for Surgical Research.

PURPOSE: This study was designed to compare the results of two methods on the rate of postoperative perineum healing. PATIENTS AND METHODS: In this prospective, randomized, multicenter trial of 234 consecutive patients undergoing abdominoperineal rectal excision for carcinoma, 48 had unsatisfactory hemostasis or intraoperative gross septic contamination. Three patients were withdrawn because of protocol violation. Of the 45 remaining patients, 21 were randomized to undergo primary closure of the perineum with drainage while 24 underwent packing. Preoperative factors (sex, age, degree of obesity, weight loss, anemia, or presence of ascites), intraoperative findings (Dukes stage, degree of hemostasis, gross septic contamination), and postoperative oncologic courses (recurrence, mortality rate) were similar in both groups. All patients were followed for at least 12 months or until their demise. RESULTS: There was no significant difference in the number of early (one vs. zero) or late (five vs. four) deaths between primary closure and packing groups, respectively. Median duration of hospital stay was 25 and 27 days, respectively. Primary closure was associated with a significantly higher rate of healed perineums at one month (30 percent vs. 0 percent) (P = 0.01) and a shorter delay to complete cicatrization (median, 47 vs. 69 days) (P < 0.01). From three months onward, there was no difference in healing between the two groups, but two patients in the packing group had not healed at one year. Conversely, hematoma, perineal abscess, and reoperations were significantly more frequent (P < 0.01) in the primary closure group. CONCLUSION: Primary closure associated with drainage after abdominoperineal resection for carcinoma expedites perineal healing but morbidity is higher.

Adult↗
PubMed1989

Postoperative changes in hemostasis analyzed by the serial determination of fibrinopeptides and D-dimer.

In order to elucidate the postoperative changes in hemostasis, three molecular markers; fibrinopeptide A (FPA), fibrinopeptide B beta 15-42 (B beta 15-42) and D-dimer, were serially determined in 27 gastric resections (group A), 27 hepatic resections (group B) and 4 probe laparotomies (group C). Unexpectedly, a postoperative hypercoagulable state was transient and of a low magnitude, as determined by the obtained value of FPA. On the other hand, a significant fibrinolysis (an elevation of B beta 15-42) was observed immediately after surgery which continued for over 10 days. The early phase of fibrinolysis, up until the 3rd postoperative day, is likely to be primary fibrinolysis, as it was not accompanied by the formation of D-dimer, which results from the digestion of fibrin by plasmin. The late phase, however, is considered to be secondary fibrinolysis, as D-dimer was elevated during this phase. Despite the different surgical procedures, these changes were basically similar between the patients who underwent gastric resections and those who underwent liver resections. The postoperative changes in hemostasis as presented herein may therefore be the general physiological response, at least against abdominal surgery.

Abdomen↗
PubMed2006

The effects of colloid solutions on hemostasis.

PURPOSE: Colloid solutions are widely used to prevent or to correct hypovolemia in surgical patients. Although more efficacious than crystalloids, they are more expensive and can be associated with adverse effects, in particular when they interfere with the hemostatic system. METHODS: This narrative review focuses on the effects of albumin and synthetic colloids on the biological markers of coagulation and their clinical consequences. RESULTS: All colloidal plasma substitutes interfere with the physiological mechanisms of hemostasis either through a non-specific effect correlated to the degree of hemodilution or through specific actions of these macromolecules on platelet function, coagulation proteins, and the fibrinolytic system. Albumin has the least effect, while high molecular weight (Mw) dextrans and hydroxyethyl starches (HES) have the most significant effects. Gelatins and medium Mw HES with a low molar substitution ratio have moderate and, probably, comparable effects. The use of dextrans and high in vivo Mw HES may be associated with increased bleeding, while gelatins and low in vivo Mw HES are unlikely to have such an effect. CONCLUSIONS: In most cases, the clinical consequences of the biological effects of colloids on hemostasis are limited, provided that safety considerations are observed (maximum daily dosage, duration of treatment, patient's hemostatic status, clinical conditions). The implications may be different in patients with hemostatic disorders, either inherited or related to preoperative antiplatelet or anticoagulant treatment. In these patients, crystalloids, gelatins or even albumin solutions should be preferred when hemodilution exceeds 30% of the circulating blood volume.

Animals↗
PubMed1998

An effective method for improving hemostasis in aortic root replacement with a composite graft.

Hemostasis during aortic root replacement with a composite graft, consisting of a separate Dacron graft and a valve, was markedly improved by using a supra-annular aortic wall reinforcing suture (SAWR). Between February 1994 and January 1998, 14 consecutive patients (10 men and 4 women) underwent replacement of the aortic valve and ascending aorta with the SAWR technique. No intraoperative bleeding of the aortic proximal suture line or early death occurred in this group. No patient required reoperation for bleeding of anastomoses. Three of 10 patients who underwent elective operations were operated on successfully without blood transfusion. In addition, no clinical complications related to the SAWR technique were observed in the follow-up period. We conclude that the SAWR technique can be performed easily and may be an effective method for improving proximal hemostasis.

Aortic Dissection↗
PubMed2001

Growth factors and hemostasis: differential effects of GM-CSF and G-CSF on coagulation activation--laboratory and clinical evidence.

Granulocyte-macrophage (GM-CSF) and granulocyte colony-stimulating factors (G-CSF) are equally effective hematopoietic growth factors in terms of their potential to shorten the period of neutropenia following high-dose chemotherapy or to mobilize hematopoietic stem cells. Thus the choice between the two preparations must be based on a comparison of adverse effects. Both GM-CSF and G-CSF have been implicated in disturbances of the hemostatic system, resulting in both hemorrhagic and thrombotic complications. We therefore studied the effects of GM-CSF and G-CSF therapy on hemostasis both ex vivo and clinically. In a prospective, non-randomized study 34 patients who were treated with a myeloablative regimen according to the hyper-ME+/-C protocol and stem cell or bone marrow transplantation received posttransplantation hematopoietic support with GM-CSF (n=15) or G-CSF (n=19). The patients were monitored for alterations in plasmatic coagulation parameters and clinical evidence of hemorrhagic or thrombotic events. GM-CSF, but not G-CSF, induced a significant, albeit usually mild activation of the coagulation cascade. We observed an increased frequency of veno-occlusive disease in the GM-CSF group (3/15 vs. 1/19 on G-CSF, n.s.). Other thrombotic events were rare. At the same time, hemorrhage was both more common and more severe in GM-CSF treated patients than in those on G-CSF (macroscopic hemorrhage 11/15 vs. 10/19, III hemorrhage 7/15 vs. 1/19 on GM-CSF or G-CSF, respectively). In conclusion, unlike G-CSF, if given after hyper-ME chemotherapy plus stem cell or bone marrow transplantation, at the dosage used here GM-CSF induced an activation of the coagulation system and was associated with an increased risk of hemostasis associated treatment complications.

Adolescent↗
PubMed2000

The efficacy of laparosonic coagulating shears for arterial division and hemostasis in porcine arteries.

BACKGROUND: Recently, the laparosonic coagulating shears (LCS) have been used widely in laparoscopic surgery. In the current study, the usefulness of LCS for arterial division and hemostasis was examined in porcine arteries. METHODS: Porcine arteries of several diameters (1, 3, and 5 mm) were removed and divided using LCS with different blade modes: shear, blunt, and flat. The division time and bursting pressure were registered. Additionally, divided sections stained by the Azan-Mallory method were observed microscopically. RESULTS: The division time was dependent on the blade modes used. With the flat mode, the bursting pressure of 5-mm arteries was significantly higher than the bursting pressure with shear and blunt modes. Histologically, cavitation and mild degeneration of the vessel walls occurred adjacent to the cutting edge. CONCLUSION: The LCS is a safe and useful device for arterial division and hemostasis for 5-mm arteries if an adequate blade mode is used.

Animals↗
PubMed2004

Duodenal gangliocytic paraganglioma treated with endoscopic hemostasis and resection.

Gangliocytic paragangliomas are exceedingly rare tumors that arise in close proximity to the papilla of Vater. There are few reports of the endoscopic resection of duodenal gangliocytic paraganglioma. A 61-year-old woman was admitted with a complaint of melena. Endoscopic examination revealed a pedunculated submucosal tumor with erosion in the third portion of the duodenum. Hemostasis, using a gold probe, was performed. Nine days later, we successfully resected the tumor, using endoscopic polypectomy. To determine the depth of tumor invasion, endoscopic ultrasonography was used. The size of the tumor was 3.0 x 2.5 x 1.0 cm. A total of 25 cases of duodenal gangliocytic paraganglioma have been reported in Japan. Generally, this tumor is considered benign. However, resection was performed in many patients because preoperative diagnosis was impossible. In Japan, no previous studies have reported using endoscopic hemostasis, to our knowledge. Our patient is the fourth in Japan to be treated by endoscopic resection. We report on our patient, with a review of the literature.

Duodenal Neoplasms↗
PubMed2007

The U.S. Thrombosis and Hemostasis Centers pilot sites program.

Venous thromboembolism (VTE) is a common disorder associated with significant morbidity and mortality. Despite important advances in understanding the etiology of VTE, delivery of care to patients with thrombosis and thrombophilia is frequently incomplete and highly variable. A comprehensive model of health care has been used successfully to treat and prevent complications for people with hemophilia and other chronic disorders. The effectiveness of an integrated healthcare model for patients with all coagulation disorders has yet to be evaluated. The Division of Hereditary Blood Disorders of the Centers for Disease Control and Prevention (CDC) is collaborating with eight Thrombosis and Hemostasis Centers (pilot sites) to provide health-related services and conduct research directed toward the reduction or prevention of complications of thrombosis and thrombophilia. The initial objectives of the collaboration are to (1) determine the efficacy of integrated multidisciplinary care and prevention services for people with hemostatic disorders, (2) assess unmet needs for service delivery and identify outreach strategies to improve access to care, (3) develop effective messages aimed at disease management and prevention, and (4) foster the development of training programs to enhance provider skills for the delivery of patient care. To address these objectives, the investigators and CDC have developed and implemented a web-based patient registry to follow prospectively service allocation and patient outcomes. Funding for the program began in October 2001. All eight funded centers are affiliated with U.S. medical schools. Principal investigators at the centers are hematologists (five adult, two pediatric) or cardiologists. Faculty in obstetrics-gynecology, surgery, and multiple other specialties are integral to the model of care at the centers. Other critical components at the centers are clinical laboratory services, training programs, research networks, and education and outreach programs. From August 2003 to March 2006, over 2,600 patients were enrolled in the registry, accounting for a total of more than 5,000 visits to the centers. Immediate goals of the data collection at the centers are to characterize patients receiving care at centers and document the state of health services provided. Long-term goals are to evaluate prospectively clinical outcomes for patients receiving multidisciplinary care and prevention services at centers. The network of data collection across centers will facilitate future collaborative clinical and epidemiologic investigations and enhance collective expertise in hemostasis and coagulation disorders.

Academic Medical Centers↗
PubMed1983

Effects of acetylsalicylic acid and dietary intervention on primary hemostasis.

There is evidence that pathological aggregation of platelets in atherosclerotic arteries is initiated by hemorrhage through fissures in atheromatous plaques. Bleeding time determination reflects in vivo the physiologic function of platelets in their aggregation in injured vessels and can be used as a relevant model for primary hemostasis in investigations with antithrombotic aims. Acetylsalicylic acid is known to cause prolongation of bleeding time by inhibiting prostaglandin biosynthesis. Recent experiments have shown that dietary supplementation with omega-3 polyunsaturated fatty acids results in prolongation of bleeding time and decreased platelet aggregability. This paper is mainly concerned with the effect of different doses of aspirin (3.5 mg/kg, 5 mg/kg, and 10 mg/kg), and fish diets rich in omega-3 polyunsaturated fatty acids, on bleeding time and platelet aggregation. The effects of aspirin separately, as well as aspirin administration during dietary intervention, will be described. Administration of all three dose levels of aspirin prolonged bleeding time significantly (p less than 0.001). The effect of aspirin on bleeding time was dose-dependent and an optimum interval was found. A fish diet, rich in omega-3 polyunsaturated fatty acids, causes bleeding time prolongation and decreased platelet aggregability similar to those caused by aspirin. Aspirin taken during this diet prolonged bleeding time by more than the sum of the increases in bleeding time caused by aspirin and the diet with omega-3 polyunsaturated fatty acids, separately, but the synergism was not significantly more than additive. These observations suggest that fish diets affect primary hemostasis by mechanisms different from those of aspirin. Dietary intervention may therefore enhance the antithrombotic effects of aspirin.

Animals↗
PubMed1989

Effects of prazosin on hemodynamics, hemostasis, and serum lipid and lipoprotein levels in normal and hypercholesterolemic monkeys.

The effect of prazosin on hemodynamics, hemostasis, and serum lipid and lipoprotein levels was investigated in normal and hypercholesterolemic rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) monkeys. Administration of prazosin (2 mg/kg bodyweight, orally, twice a day) for three weeks caused significant reductions in plasma cholesterol, including low- plus very low-density lipoprotein cholesterol, apolipoprotein B, and triglyceride levels. Drug therapy was associated with increased high-density lipoprotein cholesterol levels, although in one group of monkeys this rise also was associated with a reduction in apolipoprotein A1. Prazosin treatment significantly decreased mean arterial pressure in normal and hypercholesterolemic monkeys. As was expected, acute administration of phenylephrine caused mean arterial pressure to rise, with animals receiving normal- or high-cholesterol-containing diets showing similar responses. After prazosin treatment, however, a greater inhibition in the phenylephrine pressor response was observed in hypercholesterolemic monkeys compared with normal animals. Platelet aggregation in response to adenosine 5'-diphosphate, prothrombin time, and activated partial thromboplastin time were not altered by prazosin. Thus, in our nonhuman primate models of hypercholesterolemia, administration of prazosin resulted in reduction in lipid and apoprotein levels with no change in hemostasis.

Animals↗
PubMed1980

The effects of cold on hemostasis.

In vitro coagulation times and in vivo bleeding times were proportionally prolonged as the rabbit ear temperature was lowered from ambient temperature to 1 degree C. Cooling of the ear caused an increase in bleeding rather than the decrease generally attributed to cold application. The effects of temperature on the various aspects of hemostasis are discussed, and the pertinent literature is reviewed. An optimal nonfreezing cold temperature which could consistently enhance hemostasis could not be determined.

Animals↗
PubMed1982

Comparison between commercial heparin, low molecular weight heparin and pentosan polysulfate on hemostasis and platelets in vivo.

The effect of commercial heparin (MW 15000; 60 U/kg), low molecular weight heparin (MW 4500, 60 U/kg), sodium pentosan polysulfate (PZ-68) in doses of 0.5, 1, 2 and 5 mg/kg and 1 mg/kg combined with dextran 70 (0.5 g/kg) on microvascular hemostasis and platelet activity in vivo was investigated in the microcirculation of rabbit mesentery and ear chamber, respectively. Low molecular weight heparin did not alter the hemostasis: nonetheless, commercial heparin and PZ-68 interfered with the hemostatic mechanism by decreasing the stability of the hemostatic plug. This abnormality was more apparent in the venular than in the arteriolar system. Both heparins exhibited a trend towards an increase in platelet reactivity and the reverse was observed following the administration of PZ-68.

Animals↗
PubMed1985

The effect of inhibition of thromboxane synthesis in experimental thrombosis and hemostasis.

The effect of a selective inhibitor of thromboxane synthesis (dazoxiben) was evaluated in different acute models for thrombosis and hemostasis. Dazoxiben significantly reduced the thrombogenicity of the modified human umbilical vein (Dardik Biograft) inserted in the carotid artery position in sheep. The effect was evident concerning patency, thrombus weight and platelet accumulation at the distal anastomosis. This paralleled a decreased production of thromboxane in both anastomoses and the midgraft region. Dazoxiben did not reduce either the frequency of jugular vein thrombosis (induced by a combination of endothelial damage and flow restriction) or arteriolar microembolism after laser injury in rabbits. Neither did it influence initial hemostasis as evaluated by measuring the hemostatic plug formation in the rabbit mesenteric microcirculation. It is concluded that thromboxane synthesis inhibition may be of value when attempting to improve the performance of small diameter vascular prostheses, the data obtained indicating a low risk for hemorrhagic complications.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Effects of verapamil, diltiazem and nifedipine on some parameters of hemostasis in the rat.

Together with a mechanism such as activation of the coagulation system, vascular smooth muscle contraction and the activation of blood platelets are important processes in the hemostasis. Various calcium channel blockers besides those found to be vasodilators (1) have been shown to influence the functioning of blood platelets (2). They inhibit the aggregation induced by ADP, adrenaline, arachidonic acid or collagen (3). From these data it has been suggested that significant differences exist in the ability of calcium channel blockers to inhibit aggregatory responses (4). In order to elucidate further the possible role of calcium channel blockers in hemostasis we analyzed the effect of verapamil, diltiazem and nifedipine on the bleeding time, the amount of initial blood loss, platelet aggregation and some coagulation parameters in rats.

Animals↗
PubMed1982

The use of the fibrin adhesion system for local hemostasis in oral surgery.

In 144 patients with bleeding disorders and in 11 patients with normal coagulation, 517 wound sealings were performed using the fibrin adhesion system (FAS) with the primary object of local hemostasis. Excellent results were obtained in patients with bleeding disorders caused by impaired thrombocyte function or anticoagulant therapy. Replacement therapy or the withdrawal of anticoagulant medication was thereby avoided. Ultimate hemostasis in patients with hemophilia was achieved by fibrin sealing in combination with low-dose replacement therapy with clotting factor concentrates. Though the risk of hepatitis transmission cannot be completely ruled out, the advantages, such as excellent tissue tolerance, complete resorption, and a wide spectrum of practical uses, speak in favor of the use of this physiologic tissue adhesive.

Anticoagulants↗