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Rodgers RPC, Levin J. A Critical Reappraisal of the Bleeding Time. Semin Thromb Hemost 2024; 50:499-516. [PMID: 38086409 DOI: 10.1055/s-0043-1777307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Seminars in Thrombosis and Hemostasis (STH) celebrates 50 years of publishing in 2024. To celebrate this landmark event, STH is republishing some archival material. This manuscript represents the second most highly cited paper ever published in STH. The manuscript published without an abstract, and essentially represented a State of the Art Review on the bleeding time, a relatively invasive procedure that required an incision on the skin or earlobe of a patient, and timing how long it took for the incision to stop bleeding. The bleeding time test was first described in 1901 by the French physician Milian, who presented three studies of bleeding from stab wounds made in the fingertips of healthy and diseased subjects. In 1910, Duke observed the duration of bleeding from small incisions of the ear lobe, and pointed out that the duration of bleeding was increased in instances of reduced platelet counts. The test was subsequently repeatedly modified, and numerous variants of the test, including semiautomated methods, were described by several workers. The most frequently utilised test reflected one described by Ivy and coworkers, who shifted the location of the incision to the volar aspect of the forearm and applied a blood pressure cuff to the arm to maintain a standard venous pressure. The bleeding time has been proposed for use as a diagnostic test for platelet-related bleeding disorders, a measure of efficacy in various forms of therapy, and as a prognosticator of abnormal bleeding. The authors to the current review reevaluated the bleeding time literature using methods to assess the performance of the test in 1990, locating 862 printed documents that discussed the bleeding time, the majority in peer-reviewed professional journals. As this is a republication of archival material, transformed into a modern format, we apologise in advance for any errors introduced during this transformation.
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Affiliation(s)
- R P Channing Rodgers
- Department of Laboratory Medicine, School of Medicine, University of California, San Francisco, California
- The Veterans Administration Medical Center, San Francisco, California
| | - Jack Levin
- Department of Laboratory Medicine, School of Medicine, University of California, San Francisco, California
- The Veterans Administration Medical Center, San Francisco, California
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Aparna M. A medical elaboration on von Willebrand disease with its dental management. JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY MEDICINE AND PATHOLOGY 2016. [DOI: 10.1016/j.ajoms.2016.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Nichols WL, Hultin MB, James AH, Manco-Johnson MJ, Montgomery RR, Ortel TL, Rick ME, Sadler JE, Weinstein M, Yawn BP. von Willebrand disease (VWD): evidence-based diagnosis and management guidelines, the National Heart, Lung, and Blood Institute (NHLBI) Expert Panel report (USA). Haemophilia 2008; 14:171-232. [PMID: 18315614 DOI: 10.1111/j.1365-2516.2007.01643.x] [Citation(s) in RCA: 580] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- W L Nichols
- Special Coagulation Laboratory, Division of Hematopathology, Department of Laboratory Medicine and Pathology, College of Medicine, Mayo Clinic, Rochester, MN, USA.
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Adams GL, Manson RJ, Turner I, Sindram D, Lawson JH. The Balance of Thrombosis and Hemorrhage in Surgery. Hematol Oncol Clin North Am 2007; 21:13-24. [PMID: 17258115 DOI: 10.1016/j.hoc.2006.11.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Postoperative hemorrhage and thrombosis is a significant problem during the perioperative period. Understanding the complex and dynamic interplay of factors, proteins, and enzymes during coagulation is imperative to maintain balance between hemostasis and thrombosis. To improve patient outcome, each patient should be risk stratified for bleeding or thrombosis during the preoperative examination. Additional research focused on improvement in screening tools, monitoring, and therapeutic regimens for surgical patients with a coagulopathy are warranted.
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Affiliation(s)
- George L Adams
- Department of Medicine, Duke University Medical Center, Box 2622, MSRB, Research Drive, Durham, NC 27710, USA
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Troost MM, van Genderen PPJ. Excessive prolongation of the Ivy bleeding time after aspirin in essential thrombocythemia is also demonstrable in vitro in the high shear stress system PFA-100. Ann Hematol 2002. [DOI: 10.1007/s00277-002-0462-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can produce a mild, systemic hemostatic defect by inhibiting normal platelet function. Aspirin acetylates and permanently inactivates cyclooxygenase (COX), while nonaspirin NSAIDs reversibly block COX; thus, all of these drugs cause platelet dysfunction by inhibiting the formation of thromboxane A2, a platelet-activating and vasoconstricting eicosanoid. However, spontaneous bleeding complications outside the gastrointestinal tract very rarely result from the use of aspirin and other NSAIDs in individuals who are otherwise hemostatically normal. Most types of surgery are not usually associated with clinically significant bleeding in patients taking these drugs, making it typically unnecessary to discontinue them and thus delay surgery for the purpose of restoring normal hemostasis. Exceptions may include operations at sites where optimal hemostasis is critical, surgical manipulation of the genitourinary tract and oral cavity, and possibly cardiac surgery. Factors that increase the risk of bleeding with aspirin and other NSAIDs include coexisting coagulation abnormalities and the simultaneous use of alcohol or anticoagulants.
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Affiliation(s)
- A I Schafer
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
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Abstract
BACKGROUND In order to exclude hemorrhagic diathesis, e.g. before diagnostic measures carrying the risk of bleeding or in preoperative situations, a graded screening is advisable. PROCEDURE During the first stage, besides the anamnesis, clinical examination and classification of relevant concomitant diseases (e.g. liver cirrhosis or renal insufficiency), basic laboratory examinations such as prothrombin time, activated partial thromboplastin time (aPTT) and platelet count must be carried out. Should all these measures produce no noteworthy results, no further examinations are necessary. However, in the case of test results within normal limits accompanied by an unsatisfactory anamnesis and/or conspicuous clinical findings, the second stage should include examination of bleeding time according to Mielke to exclude a relevant platelet dysfunction. Should this be inconspicuous a third stage should follow in which successive implementation is made of fibrinogen according to Clauss, the Rumpel-Leede test (to exclude heightened capillary fragility), factor XIII and alpha 2-antiplasmin. The methodical snares of the parameters mentioned will be explained in full.
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Affiliation(s)
- N Maurin
- Medizinische Klinik des St.-Johannes Hospitals Bonn
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Abstract
BACKGROUND Several opinions prevail on the necessity and on the choice of laboratory coagulation tests to perform before cardiac operations. This review aims at providing simple and clinically relevant recommendations. METHODS The literature on preoperative coagulation testing was reexamined, taking into account the low prevalence of unknown and unsuspected hemorrhagic disease, and the risk of false positive results. RESULTS Carefully controlled, randomized trials are lacking but it seems appropriate to perform a few inexpensive tests (platelet count, activated partial thromboplastin time, and prothrombin time), mainly to obtain baseline values for patients who are about to undergo a major hemostatic challenge. A more complete coagulation profile (eg. bleeding time, fibrinogen concentration, thrombin time) should be considered in patients who present with a history of bleeding. CONCLUSIONS A careful medical history is the key element to detect a bleeding disorder. Only a very limited coagulation profile should be obtained in asymptomatic patients before cardiac operations.
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Affiliation(s)
- P de Moerloose
- Department of Medicine, University Hospital, Geneva, Switzerland
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Lanas AI, Arroyo MT, Esteva F, Cornudella R, Hirschowitz BI, Sáinz R. Aspirin related gastrointestinal bleeders have an exaggerated bleeding time response due to aspirin use. Gut 1996; 39:654-60. [PMID: 9026478 PMCID: PMC1383387 DOI: 10.1136/gut.39.5.654] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Gastrointestinal bleeding is related to non-steroidal anti-inflammatory drug (NSAID) use, especially aspirin, but only a small subset of users bleed. AIM To look for risk factors or mechanisms whereby aspirin may promote gastrointestinal bleeding. PATIENTS Sixty one patients with previous aspirin related upper gastrointestinal bleeding and 61 matched controls. METHODS Patients and controls were given 375 mg of aspirin and sequential skin bleeding time and blood aspirin levels were measured. Additional studies included platelet lumiaggregation, von Willebrand factor, Factor VIII, and coagulation studies. RESULTS Baseline skin bleeding time was similar in bleeders and controls, but bleeders had a more prolonged skin bleeding time after aspirin use. Hyper-response was more frequent in bleeders (30% v 9.3%; p < 0.01) and was associated with more than one previous separate bleeding event and a lower packed cell volume during the preceding bleeding episode. No differences were found in other factors studied. Logistic regression analysis identified prolonged skin bleeding time after aspirin use as an independent factor contributing to aspirin related gastrointestinal bleeding (RR = 5.4; 95% CI: 1.8 to 17.1). CONCLUSIONS 30% of patients with a history of aspirin related gastrointestinal bleeding have an exaggerated prolongation of skin bleeding time in response to aspirin, which may be a risk factor for bleeding. This intrinsic defect or to subclinical von Willebrand disease or different aspirin metabolism.
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Affiliation(s)
- A I Lanas
- Service of Gastroenterology, Hospital Clínico Universitario, Zaragoza, Spain
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Schafer AI. Effects of nonsteroidal antiinflammatory drugs on platelet function and systemic hemostasis. J Clin Pharmacol 1995; 35:209-19. [PMID: 7608308 DOI: 10.1002/j.1552-4604.1995.tb04050.x] [Citation(s) in RCA: 224] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Aspirin and nonaspirin nonsteroidal antiinflammatory drugs (NSAIDs) inhibit platelet cyclooxygenase, thereby blocking the formation of thromboxane A2. These drugs produce a systemic bleeding tendency by impairing thromboxane-dependent platelet aggregation and consequently prolonging the bleeding time. Aspirin exerts these effects by irreversibly blocking cyclooxygenase and, therefore, its actions persist for the circulating lifetime of the platelet. Nonaspirin NSAIDs inhibit cyclooxygenase reversibly and, therefore, the duration of their action depends on specific drug dose, serum level, and half-life. The clinical risks of bleeding with aspirin or nonaspirin NSAIDs are enhanced by the concomitant use of alcohol or anticoagulants and by associated conditions, including advanced age, liver disease, and other coexisting coagulopathies.
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Affiliation(s)
- A I Schafer
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
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Lawrence C, Sakuntabhai A, Tiling-Grosse S. Effect of aspirin and nonsteroidal antiinflammatory drug therapy on bleeding complications in dermatologic surgical patients. J Am Acad Dermatol 1994; 31:988-92. [PMID: 7962782 DOI: 10.1016/s0190-9622(94)70269-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Aspirin and nonsteroidal antiinflammatory drugs (NSAIDs) inhibit platelet cyclooxygenase activity, resulting in altered platelet function and thus potentially enhanced bleeding. OBJECTIVE We examined the frequency of operative bleeding complications in dermatologic surgical patients taking these drugs and the value of template bleeding time estimates in predicting this complication. METHODS Bleeding time was measured with and without therapy in 23 patients and was correlated to bleeding complications after skin tumor or benign lesion excision in 40 patients taking aspirin, 21 taking NSAIDs, and 20 taking neither drug. RESULTS Bleeding time dropped significantly (p < 0.01) when patients stopped therapy for at least 5 days (median, 7 days), although bleeding time was prolonged in only 6 of 16 patients taking aspirin and 2 of 7 taking NSAID. In patients who continued antiplatelet drugs during surgery, bleeding time was prolonged in 8 of 40 patients taking aspirin and in 1 of 21 treated with NSAIDs. Excessive intraoperative bleeding occurred in three aspirin-treated patients, all of whom had a prolonged bleeding time, compared with none of those with normal bleeding times (p < 0.001, Fisher's exact probability test) and with none of those taking NSAIDs. Postoperative ooze requiring a dressing replacement occurred in one NSAID-treated patient and in three patients taking neither drug. CONCLUSION Bleeding time is increased by aspirin and NSAID therapy but is prolonged beyond the normal range in only approximately 25% of aspirin-treated and 10% of NSAID-treated patients. Intraoperative bleeding complications occurred only in patients receiving aspirin who had a prolonged bleeding time. Postoperative oozing occurred only in NSAID-treated and in untreated patients and thus is probably unrelated to antiplatelet therapy. Patients with a normal bleeding time can continue aspirin or NSAID therapy before dermatologic surgery.
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Affiliation(s)
- C Lawrence
- Department of Dermatology, Royal Victoria Infirmary, Newcastle, UK
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Freed MI, Audet PR, Zariffa N, Krishna GG, Ilson BE, Everitt DE, Brown LE, Rizzo SM, Nichols AI, Jorkasky DK. Comparative effects of nabumetone, sulindac, and indomethacin on urinary prostaglandin excretion and platelet function in volunteers. J Clin Pharmacol 1994; 34:1098-108. [PMID: 7876402 DOI: 10.1002/j.1552-4604.1994.tb01987.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nonsteroidal antiinflammatory drugs differ with respect to their effects on prostaglandin metabolism in various tissues, a property that may be partly responsible for some of the differences in the pharmacologic activities and side-effect profiles that are associated with their use. The effects of nabumetone on urinary prostaglandin excretion have not been reported. Fourteen healthy females, age 21-43 years, were treated with nabumetone (NAB) 1000 mg daily, sulindac (SUL) 200 mg every 12 hours, and indomethacin (IND) 50 mg every 12 hours for 7 days in a randomized period-balanced crossover study. The effects of drug treatment on urinary prostaglandin excretion (PGE2, 6-keto-PGF1 alpha, PGF2 alpha, thromboxane [TX] B2) and platelet function (collagen-induced whole blood platelet aggregation [CIPA] and template bleeding time) were determined on day 1 and day 7. For each treatment regimen, mean baseline urinary PG excretion values were comparable for each prostanoid, but the pattern of excretion differed in response to each drug. Treatment with NAB significantly increased the urinary excretion rates of PGE2 and PGF2 alpha, but 6-keto-PGF1 alpha and TXB2 excretion were unchanged. IND treatment did not result in a significant change in PGE2 excretion but did significantly reduce urinary 6-keto-PGF1 alpha and TXB2 excretion rates. Reduced excretion of PGF2 alpha was observed on both study days during treatment with IND and SUL. SUL treatment also resulted in increased urinary PGE2 excretion while significantly reducing 6-keto-PGF1 alpha excretion on day 7. Significant differences were observed between the NAB and SUL regimens with respect to PGF2 alpha excretion and between the NAB and SUL regimens for PGE2, PGF2 alpha, 6-keto-PGF alpha 1 (on day 1 only) and TXB2 (on day 1 only). Neither NAB nor SUL caused inhibition of CIPA or bleeding time although platelet aggregation was inhibited during IND treatment. That NAB treatment was neither associated with alterations in platelet function nor decreases in the urinary excretion of the vasodilatory prostaglandins, PGE2 and 6-keto-PGF1 alpha, suggests that NAB possesses renal sparing properties.
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Affiliation(s)
- M I Freed
- Clinical Research Unit, SmithKline Beecham, Presbyterian Medical Center of Philadelphia, PA 19104
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Abstract
Easy bruisability raises the issue of bleeding during otolaryngological surgery. Ten female patients with easy bruisability were evaluated by aspirin challenge; clinical history and screening coagulation studies in these patients had revealed no evidence of a bleeding disorder. The baseline Ivy bleeding time (BT) test (4.5 to 9.5 minutes) was found to be normal in 6 patients and prolonged in 4 patients. Following treatment with aspirin, the bleeding time prolonged significantly in the three groups evaluated: normal controls (6.0 +/- 1.5 minutes vs. 8.4 +/- 2.0 minutes), patients with easy bruisability and a normal baseline (7.8 +/- 1.3 minutes vs. 12.0 +/- 1.6 minutes), and patients with easy bruisability and an abnormal baseline (11.0 +/- 0.7 minutes vs. 14.5 +/- 0.9 minutes). Administration of DDAVP (desmopressin acetate) 0.3 microgram/kg normalized the prolonged bleeding times in all groups after 7 days of daily aspirin therapy. Performing bleeding times before aspirin challenge, after aspirin challenge, and after DDAVP therapy following aspirin challenge is both a useful way of confirming aspirin sensitivity in patients with easy bruisability as well as a useful way of documenting improved hemostasis after DDAVP administration.
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Affiliation(s)
- M D Lekas
- Department of Surgery, Brown University School of Medicine, Providence, RI
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Parkin JD, O'Neill AI, Ibrahim KMA, Butcher LA, Smith IL. Mild bleeding disorders: A clinical and laboratory study. Med J Aust 1992. [DOI: 10.5694/j.1326-5377.1992.tb121458.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- J Des Parkin
- Haematology DepartmentRepatriation General HospitalBanksia StreetHeidelberg WestVIC3081
| | - Anthony I O'Neill
- Haematology DepartmentRepatriation General HospitalBanksia StreetHeidelberg WestVIC3081
| | - Kamal M A Ibrahim
- Haematology DepartmentRepatriation General HospitalBanksia StreetHeidelberg WestVIC3081
| | - Lynda A Butcher
- Haematology DepartmentRepatriation General HospitalBanksia StreetHeidelberg WestVIC3081
| | - Ian L Smith
- Haematology DepartmentAustin HospitalStudley RoadHeidelbergVIC3084
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Affiliation(s)
- J N George
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City 73190
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Caughman WF, McCoy BP, Sisk AL, Lutcher CL. When a patient with a bleeding disorder needs dental work. How you can work with the dentist to prevent a crisis. Postgrad Med 1990; 88:175-82. [PMID: 2235781 DOI: 10.1080/00325481.1990.11716431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Patients with bleeding disorders need close cooperation between their physician and their dental practitioner to receive safe, comprehensive dental care. When indicated, physicians must advise a compromised treatment plan to avoid deep injections or surgical procedures that may initiate a bleeding crisis in patients at risk. The conditions most commonly seen that require special consideration are long-term use of antithrombotic agents, platelet dysfunction caused by chronic renal failure, and congenital clotting factor deficiencies. Even these patients may undergo a high-risk procedure, such as periodontal surgery, with adequate precautions and preparation.
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Affiliation(s)
- W F Caughman
- Department of Restorative Dentistry, Medical College of Georgia School of Dentistry, Augusta 30912
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Abstract
A randomised double-blind controlled study was performed to examine the effect of diclofenac on skin bleeding time and in vitro whole blood platelet aggregation. Twenty thoracotomy patients were studied; 10 were given diclofenac 75 mg intramuscularly at induction of anaesthesia, and 10 formed a control group. Skin bleeding times and platelet aggregation tests were performed the day before and repeated one hour after induction of anaesthesia. Diclofenac prolonged skin bleeding time and reduced platelet aggregation. There were no significant changes in the control group.
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Affiliation(s)
- I Power
- University Department of Anaesthetics, Royal Infirmary, Edinburgh
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Abstract
The BT as a test of hemostatic function was first described 80 years ago. It has generally been considered a primitive and tedious test. Improvements in technique and standardization have increased the BT's reliability and led to its consideration as a preoperative screening measure. Current use has not been widespread, however, except for patients undergoing neurosurgery and organ biopsy. Recently, though, there has been a renewed interest in the BT for patients receiving thrombolytic therapy because levels of fibrinogen and fibrin(ogen) degradation products have been only weak predictors of hemorrhagic complications. The rationale for using the BT in this setting is that thrombolysis appears to impair platelet function, either through depletion of platelet granules or through direct proteolytic actions on platelets. Further research will determine whether these platelet effects are manifest as BT prolongation; whether increased BT will correlate with hemorrhagic complications; and, finally, whether patients who fail to achieve clot lysis or those at risk for bleeding can be identified prospectively.
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Affiliation(s)
- D R Hirsch
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
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Abstract
Thirty-two patients with thrombocythemia associated with myeloproliferative syndromes were selected on the basis of normal bleeding time and absence of hemorrhagic or thrombotic history. Twenty-five control subjects were studied simultaneously. They were all given a single intravenous infusion of 500 mg of aspirin (lysine acetylsalicylate), and bleeding time was measured two hours later. Both in the control group and in the patient group, aspirin significantly prolonged the bleeding time, but the average prolongation was significantly more pronounced in the patients. In comparison with the control subjects, the patients had a statistically significant reduction of platelet serotonin content and no difference in the production of platelet lipoxygenase derivative 12-HETE or plasma von Willebrand factor properties. Fourteen patients had abnormal platelet aggregation in response to adenosine diphosphate, adrenaline (epinephrine), or collagen. In six of them, all with very low serotonin content, the bleeding time was prolonged above the upper limit of the post-aspirin values in the control group. Thus, cyclooxygenase inhibition by aspirin unmasked a bleeding tendency in patients with a severe reduction in platelet dense bodies content. These findings might be relevant in relation to the use of antiplatelet drugs.
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Abstract
Uraemic patients have a bleeding tendency thought to be due to platelet functional abnormalities, but haemodialysis paradoxically exposes patients to the thrombotic complications of arteriovenous shunts. Possible treatments of the latter have been debated. The effect of 100 mg/m2 aspirin on haemostatic function was studied in 29 uraemic patients on chronic haemodialysis who had normal or only slightly prolonged bleeding times. Aspirin did not significantly affect bleeding time in healthy controls but prolonged it in uraemic patients. In 12 of the 29 uraemic patients, the bleeding time after aspirin was longer than 15 min. Aspirin completely abolished thromboxane A2 generation by both control and uraemic platelets, indicating that its effect in uraemic patients is not due to differential inhibition of platelet cyclo-oxygenase. Products of lipoxygenase enzyme and factor VIII von Willebrand factor did not seem to have a role. A careful risk-benefit evaluation is necessary before giving aspirin to uraemic patients on haemodialysis to prevent thrombosis of the arteriovenous shunt.
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Abstract
The bleeding time is the most frequently used test of platelet function. This review of the literature relating to the bleeding time outlines the causes and management of prolonged bleeding time. The bleeding time appears to have its greatest utility in evaluation of a patient with active bleeding or one with a well-documented bleeding history. It should not be used as a substitute for a clinical history, since there is insufficient information available to calculate its sensitivity, specificity, or predictive value with regard to peri- or postoperative hemorrhage.
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