Telemedicine and computers in diabetic retinopathy screening

American Journal of Hematology, 2003

European Journal of Vascular and Endovascular Surgery, 2005

Background. Routine thrombophilia testing is controversial because of the low yield of positive tests, costs involved, and debate about the clinical usefulness of the data obtained from testing. Laboratory investigations are rarely done for those with superficial venous thrombosis (SVT) or isolated calf vein thrombosis (CVT) which are often not treated with anticoagulants. Objective. To identify the incidence of markers of thrombophilia in patients with deep vein thrombosis (DVT), SVT, isolated CVT or a history of thrombosis in a referral practice. Methods. One hundred and sixty-six patients were referred to our thrombosis unit for consultation, including patients with SVT, DVT, and preoperative patients with a previous history of SVT or DVT. Patients underwent thrombophilia screening and patients with a diagnosis of SVT or DVT were confirmed by bilateral duplex ultrasonography of all lower limb veins. Thrombophilia testing included factor V Leiden (FVL), prothrombin 20210A mutation (P2), methylene tetrahydrofolate reductase deficiency (MTHFR), fasting serum homocysteine (HC), lupus anticoagulant (LA), anticardiolipin antibodies (ACA), antithrombin deficiency (AT), protein S deficiency (PS), and protein C deficiency (PC). Results. The incidence of any significant abnormality in patients with DVT was 27/44 (61%; 95% Confidence interval [CI], 47-76%) and 10 of these patients were positive for FVL (23%; 95% CI, 10-35%). Twelve patients with isolated CVT were seen and five had at least one abnormality (42%; 95% CI, 14-70%) including one with FVL (8%; 95% CI, 0-24%). Thirtynine patients with isolated SVT were seen including 14 with at least one abnormality (36%; 95% CI, 21-51%) and five of these patients with SVT had FVL (13%; 95% CI, 2-23%). Nine patients with recurrent DVT were seen and five of these had at least one abnormal test (56%; 95% CI, 23-88%). Finally, 18 of the 166 patients had more than one abnormality (11%; 95% CI, 6-16%). Conclusion. The presence of one or more markers of thrombophilia was significantly higher in this patient population compared to reports from other centres. This study identified 18/166 (10.8%; 95% CI, 6-16%) with more than one defect where lifelong anticoagulation might be considered. The results in this subset of patients as well as the serious defects found in some patients with provoked DVT, isolated CVT or isolated SVT demonstrate the value of this screening program to both these patients and their blood relatives. On the other hand, this is a small series from a referral practice where the incidence of these defects is greater than one would expect in the general population. These studies are preliminary and it is not recommended that all VTE patients should be screened on the basis of the current report.

Journal of thrombosis and thrombolysis, 2001

Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2015

Annals of Emergency Medicine, 2003

Background: Because clinical diagnosis is inaccurate, objective testing is usually considered necessary when patients present with suspected deep venous thrombosis (DVT).

Annals of Internal Medicine, 2013

Background: D-Dimer testing is sensitive but not specific for diagnosing deep venous thrombosis (DVT). Changing the use of testing and the threshold level for a positive test result on the basis of risk for DVT might improve the tradeoff between sensitivity and specificity and reduce the need for testing. Objective: To determine whether using a selective D-dimer testing strategy based on clinical pretest probability (C-PTP) for DVT is safe and reduces diagnostic testing compared with using a single D-dimer threshold for all patients. Design: Randomized, multicenter, controlled trial. Patients were allocated using a central automated system. Ultrasonographers and study adjudicators but not other study personnel were blinded to trial allocation. (ClinicalTrials.gov: NCT00157677) Setting: 5 Canadian hospitals. Patients: Consecutive symptomatic patients with a first episode of suspected DVT. Intervention: Selective testing (n ϭ 860), defined as D-dimer testing for outpatients with low or moderate C-PTP (DVT excluded at D-dimer levels Ͻ1.0 g/mL [low C-PTP] or Ͻ0.5 g/mL [moderate C-PTP]) and venous ultrasonography without D-dimer testing for outpatients with high C-PTP and inpatients, or uniform testing (n ϭ 863), defined as D-dimer testing for all participants (DVT excluded at D-dimer levels Ͻ0.5 g/mL). Measurements: The proportion of patients not diagnosed with DVT during initial testing who had symptomatic venous thromboembolism during 3-month follow-up and the proportion of patients undergoing D-dimer testing and ultrasonography. Results: The incidence of symptomatic venous thromboembolism at 3 months was 0.5% in both study groups (difference, 0.0 percentage point [95% CI, Ϫ0.8 to 0.8 percentage points]). Selective testing reduced the proportion of patients who required D-dimer testing by 21.8 percentage points (CI, 19.1 to 24.8 percentage points). It reduced the proportion who required ultrasonography by 7.6 percentage points (CI, 2.9 to 12.2 percentage points) overall and by 21.0 percentage points (CI, 14.2 to 27.6 percentage points) in outpatients with low C-PTP. Limitation: Results may not be generalizable to all D-dimer assays or patients with previous DVT, study personnel were not blinded, and the trial was stopped prematurely. Conclusion: A selective D-dimer testing strategy seems as safe as and more efficient than having everyone undergo D-dimer testing when diagnosing a first episode of suspected DVT.

Future Science OA, 2019

Much research to identify clinically useful molecular biomarkers that reflect overall thrombotic status has been performed over the last few decades. One of the most probable molecular biomarkers appears to be D-dimer, but this lacks specificity, with poor predictive value in arterial thrombosis . It is doubtful whether any single molecular biomarker could predict a multifactorial event such as an arterial thrombotic event. Another important problem is that in vitro anticoagulation of blood sample affects the results of the test used and renders it rather unphysiological . However, some promising nonanticoagulated global hemostasis and thrombosis tests have been developed and have been used successfully in diagnosis and medical discovery and developments . These tests have been well developed and proven to be highly important for both diagnostic and therapeutic purposes. Blood is drawn directly from an antecubital vein over a prothrombotic surface consisting of either human type III collagen fibrils or human tissue factor/phospholipids, which promotes thrombus formation by activation of both platelets and coagulation. Thrombus formation is performed at vessel wall shear rates varying from 100 to 32,000 s -1 . The impact of vessel wall shear rates on the various mechanisms of thrombus formation and on anticoagulant and antiplatelet agents are very high. Platelet activation is increased by increasing arterial wall shear rate, whereas coagulation is increased by low venous wall shear rates. These physical shear rate effects have important effects on the activities of many antiplatelet and anticoagulant agents. Also, impacts of cigarette smoking and physical activities on thrombus formation have been studied with this global nonanticoagulated blood test . It should also be mentioned that the use of these human nonanticoagulated blood tests is of importance for the antithrombotic and hematologic pharma industry, since animal studies may not always predict the human reaction. Furthermore, implication of these models in the pharma industry has reduced costs of the discovery and developmental activities and the need for animal experiments.

Biomedical Papers, 2009

Journal of Internal Medicine, 1994

Hansson P-0, Eriksson H, Eriksson E, Jagenburg R, Lukes P, Risberg B (

Blood Coagulation & Fibrinolysis, 2001

The thromboelastograph (TEG), a measure of global haemostasis, is routinely used during cardiac and hepatic surgery to optimize blood product selection and usage. It has recently been suggested that it may also be a useful tool to screen patients with hypercoagulable states. Limited published data on performance characteristics has led to speculation regarding its consistency and, therefore, validity of the results. This study was designed to assess the effect of stability of blood samples prior to testing, repeated sampling, intra-and inter-assay variability using the native, celite, tissue factor (TF) and Reopro-modi®ed TEG. Analysis of native and celite samples after storage over 90 min showed a period of instability up to 30 min. Thereafter, all parameters between 30 and 90 min were stable [P not signi®cant (NS)]. When the same sample was repeatedly assayed, both native and celite TEG parameters showed a signi®cant change towards hypercoagulability (P < 0.01), whereas the TF and Reopro-modi®ed TEG showed no change. Intra-and inter-assay variability on samples tested after 30 min showed excellent reproducibility for all parameters (P NS). The data suggest that the TEG is a useful tool in haemostasis but requires a formal standard operating procedure to be adopted that takes into account the initial period of sample instability. Blood Coagul Fibrinolysis 12:555±561 # 2001 Lippincott Williams & Wilkins.