Abstract Venous thromboembolism (VTE) has a variable recurrence rate after the discontinuation of anticoagulant treatment. Therefore, the duration of anticoagulation therapy after a first VTE should be tailored to the estimated risk for recurrence. Anticoagulant therapy should be discontinued after the initial 3 to 6 months in those patients who had the first episode in association with temporary risk factors. The duration of anticoagulant therapy in patients who had a first episode of cancer-associated VTE should be reassessed over time based on the persistence of cancer and anticancer therapy. After 3 to 6 months of anticoagulant treatment for VTE, patients with a first unprovoked event and an estimated low risk for bleeding complications should be evaluated for indefinite treatment on an individualized basis. New oral anticoagulants have been evaluated for the extended treatment of VTE. Large phase 3 studies have shown that dabigatran, rivaroxaban, and apixaban are effective and safe in this indication. These agents do not require monitoring for dose adjustment and could make extended treatment more feasible and acceptable to patients.
The effect of various concentrations of pentoxifylline, a methylxanthine, on platelet aggregation was evaluated in vitro by Born's method. The study was performed on platelet-rich plasma obtained from two series of clinically healthy subjects: in the first, pentoxifylline was added to platelet-rich plasma just before ADP or epinephrine; in the second, pentoxifylline was incubated with platelet-rich plasma for 150 minutes at 37 degrees C before testing. Statistical analysis of the results demonstrates that pentoxifylline exerts a dose-dependent inhibiting action on platelet aggregation, particularly when epinephrine is chosen as the aggregating agent, and that the pre-incubation of pentoxifylline with blood platelets greatly enhances its inhibitory effect.
Letters3 May 2005Defining the Role of Computed Tomographic Pulmonary Angiography in Suspected Pulmonary EmbolismPieter W. Kamphuisen, MD and Giancarlo Agnelli, MDPieter W. Kamphuisen, MDFrom University of Perugia, I-06100 Perugia, Italy.Search for more papers by this author and Giancarlo Agnelli, MDFrom University of Perugia, I-06100 Perugia, Italy.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-142-9-200505030-00027 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:In many hospitals, CTPA is becoming the preferred diagnostic test for suspected acute PE. On the basis of their meta-analysis, Moores and colleagues (1) concluded that it appears to be safe to withhold anticoagulant therapy after negative CTPA results in patients with suspected PE. This may imply that CTPA could be used as the first and sole diagnostic test in these patients. We believe that this conclusion is premature for 2 reasons.First, in consecutive patients with suspected PE, the sensitivity of CTPA is only 70% and the negative likelihood ratio is 0.3 (2). This likelihood ratio ...References1. Moores LK, Jackson WL, Shorr AF, Jackson JL. Meta-analysis: outcomes in patients with suspected pulmonary embolism managed with computed tomographic pulmonary angiography. Ann Intern Med. 2004;141:866-74. [PMID: 15583229] LinkGoogle Scholar2. Perrier A, Howarth N, Didier D, Loubeyre P, Unger PF, de Moerloose P, et al. Performance of helical computed tomography in unselected outpatients with suspected pulmonary embolism. Ann Intern Med. 2001;135:88-97. [PMID: 11453707] LinkGoogle Scholar3. Goodman LR, Curtin JJ, Mewissen MW, Foley WD, Lipchik RJ, Crain MR, et al. Detection of pulmonary embolism in patients with unresolved clinical and scintigraphic diagnosis: helical CT versus angiography. AJR Am J Roentgenol. 1995;164:1369-74. [PMID: 7754875] CrossrefMedlineGoogle Scholar4. Stein PD, Hull RD, Patel KC, Olson RE, Ghali WA, Brant R, et al. D-dimer for the exclusion of acute venous thrombosis and pulmonary embolism: a systematic review. Ann Intern Med. 2004;140:589-602. [PMID: 15096330] LinkGoogle Scholar Author, Article, and Disclosure InformationAffiliations: From University of Perugia, I-06100 Perugia, Italy.Disclosures: None disclosed. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoPerformance of Helical Computed Tomography in Unselected Outpatients with Suspected Pulmonary Embolism Arnaud Perrier , Nigel Howarth , Dominique Didier , Pierre Loubeyre , Pierre-François Unger , Philippe de Moerloose , Daniel Slosman , Alain Junod , and Henri Bounameaux d-Dimer for the Exclusion of Acute Venous Thrombosis and Pulmonary Embolism Paul D. Stein , Russell D. Hull , Kalpesh C. Patel , Ronald E. Olson , William A. Ghali , Rollin Brant , Rita K. Biel , Vinay Bharadia , and Neeraj K. Kalra Meta-Analysis: Outcomes in Patients with Suspected Pulmonary Embolism Managed with Computed Tomographic Pulmonary Angiography Lisa K. Moores , William L. Jackson Jr. , Andrew F. Shorr , and Jeffrey L. Jackson Defining the Role of Computed Tomographic Pulmonary Angiography in Suspected Pulmonary Embolism Lisa K. Moores and William L. Jackson Jr Defining the Role of Computed Tomographic Pulmonary Angiography in Suspected Pulmonary Embolism Shaun D. Frost Defining the Role of Computed Tomographic Pulmonary Angiography in Suspected Pulmonary Embolism Philippe Girard Metrics Cited byOutcomes following a negative computed tomography pulmonary angiography according to pulmonary embolism prevalence: a meta‐analysis of the management outcome studiesUpdate in the diagnosis of deep-vein thrombosis and pulmonary embolism 3 May 2005Volume 142, Issue 9Page: 801-802KeywordsAngiographyAnticoagulant therapyComputed axial tomographyConflicts of interestLungsPatientsPulmonary embolismRadiation exposure ePublished: 3 May 2005 Issue Published: 3 May 2005 Copyright & PermissionsCopyright © 2005 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...
The aim of this study was to compare the effects on fibrinogenolysis and thrombin generation of two recombinant tissue-type plasminogen activator (rt-PA) regimens in patients with pulmonary embolism entering a randomised, controlled study with a 1:2 allocation ratio to rt-PA, 100 mg over 2 h (Group A) or rt-PA, 0.6 mg/kg, maximum dose 50 mg, over 15 min (Group B). In both groups the heparin infusion was stopped 2–4 h before starting thrombolytic treatment and resumed accordingly to the activated partial thromboplastin time (aPTT) or thrombin clotting time (TcT). Seventeen patients in Group A and 30 patients in Group B were evaluated before starting thrombolytic treatment and 2, 6 and 24 h after its end for the following parameters: aPTT, TcT, fibrinogen, fibrinogen degradation products (FDP), plasmin-α2 antiplasmin (PAP) and thrombin-antithrombin III (TAT) complexes. The two groups had similar coagulation parameters at baseline. Two h after starting rt-PA, the aPTT was more prolonged in Group A than in Group B patients (P = 0.01). Patients in Group B showed less reduction in plasma fibrinogen levels at all study times after rt-PA treatment (P = 0.008). The increase in plasma FDP (P = 0.037) and PAP (P = 0.001) levels was lower at 2 and 6 h samples in Group B compared with Group A. TcT was prolonged (P = 0.003) and TAT increased (P = 0.001) during treatment without differences between the two groups. AUC0–24 of fibrinogen, FDP and PAP levels confirmed the statistically significant differences (P = 0.04) between the two groups over the entire 24 h period of the study. Three patients in Group A (17.6%) and three (10.0%) in Group B suffered major or other important bleeding. Our results indicate that the administration of weight-adjusted reduced-dose rt-PA bolus produces less impairment of blood coagulation than the FDA approved regimen.