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Biomedical subjects

J E Ansell

Publications and source records attributed to J E Ansell.

At least 19 recordsLinked to original sources
PubMed1998

Oral anticoagulants for the treatment of venous thromboembolism.

Oral anticoagulation has been the mainstay of therapy for the long-term treatment of venous thromboembolism since the 1940s. The rationale for the use of oral anticoagulation is based on the results of both empirical clinical evidence and animal models of thrombosis in the 1950s and 1960s. Higher-quality studies emerged in the 1970s and 1980s demonstrating the benefit of initial heparinization for venous thromboembolism followed by long-term oral anticoagulation. Good clinical outcomes with oral anticoagulation are highly dependent on the quality of dose management. Excellent management is best achieved in a programme of focused and co-ordinated care, often referred to as an anticoagulation clinic. Such programmes achieve better outcomes at reduced costs because of fewer adverse events. New models of anticoagulation management are emerging with the development of point-of-care testing that enables patients to do their own prothrombin time monitoring and anticoagulation dose adjustment. These models have the potential to improve care further, to increase patient satisfaction and to reduce costs.

Administration, Oral↗
PubMed1998

Anticoagulation management clinics for the outpatient control of oral anticoagulants.

Oral anticoagulant therapy has a high risk-benefit profile and is labor intensive to manage. A better understanding of the indications for anticoagulation and of prothrombin time monitoring has led to improved outcomes. The development of anticoagulation management services has also improved the overall management of anticoagulation and the resulting clinical outcomes. By reducing adverse events, anticoagulation management services also result in more cost-effective therapy. Although these results have been generated by mostly nonrandomized observational studies, until better quality investigations are available, the preponderance of current clinical evidence strongly supports the value of a coordinated approach to care by an anticoagulation management service.

Administration, Oral↗
PubMed1997

Consensus guidelines for coordinated outpatient oral anticoagulation therapy management. Anticoagulation Guidelines Task Force.

OBJECTIVE: To provide primary and referring healthcare practitioners with guidelines for the provision of safe and effective anticoagulation management in any venue to standardize and improve quality of care and to permit negotiation for reimbursement from third-party payers. DATA EXTRACTION AND SYNTHESIS: Data on the current practice of anticoagulation providers and outcomes related to anticoagulation clinic care were obtained through the literature, interviews with anticoagulation providers, and a focus group meeting of anticoagulation clinic stakeholders. This information collation process revealed that an anticoagulation service consists of three separate areas for which guidelines should be developed. Based on the consensus opinions of the committee members, the literature review, and the current practice of anticoagulation services providers, a draft guideline was developed and reviewed by an independent multidisciplinary panel of anticoagulation services providers whose comments were incorporated into the final guideline. CONCLUSIONS: Systematic outpatient anticoagulation services are systems of care designed to coordinate and optimize the delivery of anticoagulation therapy by (1) evaluating patient-specific risks and benefits to determine the appropriateness of therapy; (2) facilitating the management of anticoagulation dosages and prescription pick up or delivery; (3) providing ongoing education of the patient and other caregivers about warfarin and the importance of self-care behavior leading to optimal outcomes; (4) providing continuous systematic monitoring of patients, international normalized ratio results, diet, concomitant drug therapy, and disease states; and (5) communicating with other healthcare practitioners involved in the care of the patient. To create a reproducible framework for the provision of these services, guidelines for structure, process, and outcomes of coordinated outpatient anticoagulation management services were developed. Guidelines for organization and management include (1) qualifications for personnel, (2) supervision, (3) care management and coordination, (4) communication and documentation, and (5) laboratory monitoring. Guidelines for the process of patient care include (6) patient selection and assessment, (7) initiation of therapy, (8) maintenance and management of therapy, (9) patient education, and (10) management and triage of therapy-related and unrelated problems. Guidelines for the evaluation of patient outcomes include (11) organizational components and (12) patient outcomes. The impact of these 12 guidelines on patient care and reimbursement procurement will depend on their implementation and the perceived value of their use.

Ambulatory Care↗
PubMed1995

Long-term patient self-management of oral anticoagulation.

BACKGROUND: The management of oral anticoagulation is fraught with difficulties. This study assessed a new model of anticoagulation management regarding the ability, safety, and efficacy of patients to self-monitor and self-adjust the dose of their oral anticoagulants guided by a capillary whole-blood prothrombin time (PT) monitor. METHODS: This investigation is a retrospective cohort study of 20 patients compared with 20 matched control patients receiving oral anticoagulation at a tertiary medical institution. RESULTS: Study patients monitored their PTs 2153 times during a mean interval of 44.7 months compared with 1608 PTs in matched control patients during a mean interval of 42.5 months. Study patients made an average of 11.5 dosage changes per patient, contrasted with 22.7 changes per control patient (P < .001). The PTs in study patients were within the recommended therapeutic range in 88.6% (95% confidence interval, 87.2 to 89.9) of the determinations compared with 68.0% (95% confidence interval, 65.7 to 70.3; P < .001) of the determinations made by the matched control patients. In response to the 2153 PTs, study patients made 67 (3.1%) dosage decisions that were considered incorrect based on physician guidelines. None of these changes led to adverse outcomes. There was no significant difference in complication rates between the two groups. CONCLUSIONS: Results from what is the first long-term study of patient self-monitoring of PTs and self-adjustment of the warfarin sodium dosage for oral anticoagulation suggest that patients can successfully measure their own PTs, adjust their own warfarin dosage, and achieve a degree of therapeutic effectiveness at least as good, if not better than patients managed in an anti-coagulation clinic. Larger, prospective, randomized trials are needed to confirm the efficacy and safety of this new approach to therapy and to assess its cost-effectiveness.

Administration, Oral↗
PubMed1993

Simultaneous chronic lymphocytic leukemia and chronic myelogenous leukemia. Evidence of a separate stem cell origin.

The authors studied a patient with the simultaneous occurrence of chronic lymphocytic leukemia (CLL) and chronic myelogenous leukemia (CML). The coexistence of these two hematologic malignancies leads to questions about their cell of origin. Through analysis of this patient's DNA, the authors studied the derivation of the two malignancies. They separated the blood into a myeloid-rich fraction and a fraction containing the malignant lymphocytes. JH and bcr probes were used to study these loci in the myeloid and lymphoid fractions and in unfractionated white blood cells. The authors found that the unfractionated leukocytes contained the bcr and JH rearrangements. Conversely, the lymphoid fraction contained only the JH rearrangement, and the myeloid fraction contained only the bcr rearrangement, suggesting that these malignancies arose from separate stem cells. This is the first reported patient with simultaneously occurring CML and CLL definitively shown to arise from distinct progenitors, and this report raises questions about the origin of these two cell lines.

Aged↗
PubMed1993

Oral anticoagulant therapy--50 years later.

The year 1991 marked the 50th anniversary of the first clinical use of oral anticoagulant therapy as a means of preventing thromboembolic disease. Despite long-term physician familiarity with oral anticoagulants, this mode of therapy still suffers from a relatively high-risk/safety profile. This review briefly highlights important historical and pharmacokinetic points of interest but focuses predominantly on aspects of the day-to-day management of anticoagulant therapy aiming to enhance physician performance in this therapeutic milieu. Emphasis is placed on therapeutic monitoring, understanding the prothrombin time, managing complications, and assessing future innovations for the management of a growing population of patients treated with orally administered anticoagulants.

Administration, Oral↗
PubMed1993

Coagulation abnormalities associated with the use of anabolic steroids.

According to a number of recent reports, persons using anabolic steroids may be subject to an increased risk of thromboembolism. We evaluated the effect of anabolic steroid use on the coagulation and fibrinolytic systems of 16 male bodybuilders to determine whether alterations occurred that would predispose them to a hypercoagulable state. No attempt was made to regulate or guide steroid use. Paired blood samples, both with and without steroid use, were obtained from six individuals, and the remaining subjects provided single samples obtained either during steroid use or nonuse. No differences were noted in most parameters, but we did find a significant increase in protein C antigen (p = 0.008) and free protein S antigen (p = 0.015), with a decreased euglobulin lysis time (p = 0.021) during steroid use. We also found a reduction in total cholesterol levels (p = 0.035) during steroid use. At least some of these findings suggest an activated fibrinolytic state, a known effect of anabolic steroids. The results do not support the presence of a hypercoagulable state. If anabolic steroids do produce a thrombotic tendency, they may do so through alterations in other hemostatic mechanisms or changes in lipid fractions, or more sensitive coagulation assays may be required for detection.

Adult↗
PubMed1992

Imprecision of prothrombin time monitoring of oral anticoagulation. A survey of hospital laboratories.

Prothrombin time monitoring of oral anticoagulation is highly dependent on the tissue thromboplastin used. In the United States, patients have received a higher level of anticoagulation because of the use of a less sensitive thromboplastin. Many advocate the use of an International Normalized Ratio to rectify this problem. Laboratory supervisors from all acute care hospitals in Massachusetts were surveyed to determine the disparity in thromboplastin use and reporting practices for prothrombin time testing. Eighty-eight of 103 (86%) hospitals responded. Fifty-eight lots from six manufacturers of thromboplastin were in use. The International Sensitivity Index of these lots ranged from 1.89 to 2.74. Ninety-nine percent of hospitals reported prothrombin times in raw seconds. Only 5% reported an International Normalized Ratio. Sixteen different coagulation instruments were in use. Close to 70% of laboratory supervisors had little or no understanding of the significance of an International Sensitivity Index or an International Normalized Ratio. The management of oral anticoagulation appears far less precise than had been believed. Prothrombin times in the same individual from different laboratories may have poor correlation. Based on the level of understanding of laboratory supervisors, extensive education will be necessary to change practices and improve accuracy and comparability of prothrombin time testing.

Administration, Oral↗
PubMed1992

Oral anticoagulant therapy: practical considerations.

The key to safe and effective oral anticoagulation is to have an understanding of the rationale for dosing guidelines and therapeutic ranges; an appreciation of the imprecision of prothrombin time testing and its standardization; knowledge of the factors influencing prothrombin time response; and awareness of the importance of patient empowerment via ongoing patient education. This review focuses on the routine management of oral anticoagulant therapy to provide these practical insights and to promote safe and effective therapy.

Anticoagulants↗
PubMed1992

Precoating expanded polytetrafluoroethylene grafts alters production of endothelial cell-derived thrombomodulators.

Although the use of extracellular matrix proteins to precoat small-caliber vascular grafts before endothelial cell seeding has been shown to improve cell attachment, proliferation, and adherence, the effect of precoating on the thrombomodulatory properties of the seeded cells is unknown. The use of vascular prostheses lined with confluent endothelial cell monolayers expressing optimal thromboresistant properties may enhance patency rates. In this study human saphenous vein endothelial cells were seeded onto expanded polytetrafluoroethylene (ePTFE) graft material, both unmodified and precoated with fibronectin, type I collagen, or fibronectin and type I collagen (fibronectin/type I collagen). After 3 days of in vitro cultivation, endothelial cell production of prostacyclin, tissue plasminogen activator, and plasminogen activator inhibitor was evaluated under basal conditions and after stimulation with arachidonate or thrombin. Production of tissue plasminogen activator by endothelial cells cultured on fibronectin-ePTFE was significantly greater compared with production by endothelial cells grown on noncoated or fibronectin/type I collagen-ePTFE under basal conditions (p values less than 0.01 and less than 0.05, respectively) and in response to thrombin (p values less than 0.002 and less than 0.003, respectively). Plasminogen activator inhibitor-1 production was not detected in any of the four experimental groups. Endothelial cells cultured on fibronectin-ePTFE also synthesized significantly more prostacyclin than endothelial cells grown on type I collagen- or fibronectin/type I collagen-ePTFE, under basal conditions (p values less than 0.02 and less than 0.01, respectively) and in response to arachidonate (p values less than 0.03 and less than 0.002, respectively) and thrombin (p values less than 0.003 and less than 0.002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗
PubMed1989

Cost effectiveness of monitoring warfarin therapy using standard versus capillary prothrombin times.

The authors assessed the cost effectiveness of monitoring warfarin therapy guided by standard plasma prothrombin times performed on blood samples obtained by venipuncture versus prothrombin times performed on capillary whole blood samples obtained by fingerstick. Twenty patients receiving long-term oral anticoagulation had either standard or capillary prothrombin times determined every other week for eight weeks in a cross-over design. All time intervals were monitored, including receptionist, secretarial, nursing, phlebotomy, etc., and costs for all materials, procedures, and labor were calculated. The total cost per test by the capillary whole blood prothrombin time method was significantly less than by standard prothrombin time methods ($7.55 vs. $15.64) even though the nurse-patient encounter time was greater per test for the capillary method (12.4 minutes vs. 8.3 minutes). The management of oral anticoagulation guided by prothrombin times performed on instrumentation designed to sample capillary whole blood should result in a significant cost savings, and because of the immediate availability of results, provide the potential for improved health care.

Administration, Oral↗
PubMed1988

The role of epsilon-aminocaproic acid in reducing bleeding after cardiac operation: a double-blind randomized study.

Sixty patients scheduled for elective coronary artery bypass graft operations were randomly assigned to receive epsilon-aminocaproic acid or placebo to test whether antifibrinolytic therapy would decrease postoperative bleeding. A small but significant decrease in bleeding was observed in the treated group without complications resulting from treatment with epsilon-aminocaproic acid.

Aminocaproates↗