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1.  Is stopping of anticoagulant therapy really required in a minor dental surgery? - How about in an endodontic microsurgery? 
Nowadays, oral anticoagulants are commonly prescribed to numerous patients for preventing cardiovascular accident such as thromboembolism. An important side effect of anticoagulant is anti-hemostasis. In a major surgery, the oral anticoagulant therapy (OAT) regimen must be changed before the surgery for proper post-operative bleeding control. However, in a minor dental surgery and endodontic surgery, the necessity for changing or discontinuing the OAT is open to debate. In this study, risks of the consequences were weighed and analyzed. In patients who stop the OAT, the occurrence of thromboembolic complication is rare but the result is fatal. In patients who continuing the OAT, post-operative bleeding can be controlled well with the local hemostatic measures. In the endodontic surgery, there are almost no studies about this issue. The intra-operative bleeding control is particularly important in the endodontic surgery because of its delicate and sensitive procedures such as inspection of resected root surface using dental microscope and retrograde filling. Further studies are necessary about this issue in the viewpoint of endodontic surgery.
PMCID: PMC3761118  PMID: 24010076
Anticoagulants; Bleeding control; Endodontic microsurgery; Hemorrhage; Post-operative bleeding; Thromboembolism
2.  Safety and effectiveness of point-of-care monitoring devices in patients on oral anticoagulant therapy: a meta-analysis 
Open Medicine  2007;1(3):e131-e146.
Point-of-care devices (POCDs) for monitoring long-term oral anticoagulation therapy (OAT) may be a useful alternative to laboratory-based international normalized ratio [INR] testing and clinical management.
To determine clinical outcomes of the use of POCDs for OAT management by performing a meta-analysis. Previous meta-analyses on POCDs have serious limitations.
Data sources
PubMed, the Cochrane Library, DIALOG, MEDLINE, EMBASE, BIOSIS Previews and PASCAL databases.
Study selection
Randomized controlled trials of patients on long-term OAT, comparing anticoagulation monitoring by POCD with laboratory INR testing and clinical management.
Data extraction
1) rates of major hemorrhage; 2) rates of major thromboembolic events; 3) percentage of time that the patient is maintained within the therapeutic range; 4) deaths. Outcomes were compared using a random-effects model. Summary measures of rates were determined. The quality of studies was assessed using the Jadad scale.
Data synthesis
Seventeen articles (16 studies) were included. Data analysis showed that POCD INR testing reduced the risk of major thromboembolic events (odds ratio [OR] = 0.51; 95% confidence interval [CI] 0.35–0.74), was associated with fewer deaths (OR = 0.58; 95% CI = 0.38–0.89), and resulted in better INR control compared with laboratory INR testing. No significant difference between the two management modalities with respect to odds ratios for major hemorrhage was found.
Quality scores varied from 1 to 3 (out of a maximum of 5). Only 3 studies defined how thromboembolic events would be diagnosed, casting doubt on the accuracy of the reporting of thromboembolic events. The studies suggest that only 24% of patients are good candidates for self-testing and self-management. Compared with patients managed with laboratory-based monitoring, POCD patients underwent INR testing at a much higher frequency and received much more intensive education on OAT management.
The use of POCDs is safe and may be more effective than laboratory-based monitoring. However, most patients are not good candidates for self-testing and self-management. Patient education and frequency of testing may be the most important factors in successful PODC management. Definitive conclusions about the clinical benefits provided by self-testing and self-management require more rigorously designed trials.
PMCID: PMC3113217  PMID: 21673942
3.  Use of Prothrombin Complex Concentrate for Vitamin K Antagonist Reversal before Surgical Treatment of Intracranial Hemorrhage 
Oral anticoagulant therapy (OAT) is used to prevent/treat thromboembolism. Major bleeding is common in patients on OAT; eg, warfarin increases intracranial hemorrhage (ICH) risk.
A 71-year-old male on warfarin (to reduce stroke risk) presented at Accident and Emergency Minor Injuries Unit with headache after reportedly sounding ‘drunk’. On triage, the patient appeared lucid and well. However, International Normalized Ratio (INR) was 4.1. Head computed tomography (CT) indicated a large right-sided subdural hematoma. Prothrombin complex concentrate (PCC; Beriplex® P/N, CSL Behring) with vitamin K normalized the INR within minutes of administration. The patient underwent neurosurgery without complications, and was discharged after 5 days, with no residual neurological symptoms.
ICH patients can present with no neurological signs. In OAT patients with headache, INR must be established; if ≥3.0, normalization of INR and head CT are essential. PCC is the best option to rapidly reverse anticoagulation and correct INR pre-surgery.
PMCID: PMC3096433  PMID: 21769259
anticoagulation reversal; Beriplex® P/N; computed tomography; International Normalized Ratio; intracranial hemorrhage; prothrombin complex concentrate
4.  Intracerebral haemorrhage: an often neglected medical emergency 
Intracerebral haemorrhage (ICH) is the deadliest form of stroke, carrying a mortality rate between 30% and 55%, increasing to 67% in patients on oral anticoagulant therapy (OAT). Despite its relevant incidence, the treatment of ICH has been until recently a largely neglected item, addressed by only a few trials. Early treatment of ICH in non-anticoagulated patients with recombinant activated factor VII (rFVII) has been demonstrated to be able to limit the growth of the haematoma, but such a promising result requires further confirmations. In ICH patients receiving OAT a prompt reversal of the anticoagulant effect should be warranted in order to reduce the consequences of this dreadful adverse event. In clinical practice, however, just a small proportion of anticoagulated patients receive this treatment, probably because of the fear of thromboembolic complications. It is now time to check our way of thinking about ICH, regarding and treating it as a compelling medical emergency.
PMCID: PMC2780614  PMID: 17551684
Intracerebral haemorrhage; Oral anticoagulants; Antiplatelet drugs; Recombinant activated factor VII; Emergency medicine
5.  Point-of-Care International Normalized Ratio (INR) Monitoring Devices for Patients on Long-term Oral Anticoagulation Therapy 
Executive Summary
Subject of the Evidence-Based Analysis
The purpose of this evidence based analysis report is to examine the safety and effectiveness of point-of-care (POC) international normalized ratio (INR) monitoring devices for patients on long-term oral anticoagulation therapy (OAT).
Clinical Need: Target Population and Condition
Long-term OAT is typically required by patients with mechanical heart valves, chronic atrial fibrillation, venous thromboembolism, myocardial infarction, stroke, and/or peripheral arterial occlusion. It is estimated that approximately 1% of the population receives anticoagulation treatment and, by applying this value to Ontario, there are an estimated 132,000 patients on OAT in the province, a figure that is expected to increase with the aging population.
Patients on OAT are regularly monitored and their medications adjusted to ensure that their INR scores remain in the therapeutic range. This can be challenging due to the narrow therapeutic window of warfarin and variation in individual responses. Optimal INR scores depend on the underlying indication for treatment and patient level characteristics, but for most patients the therapeutic range is an INR score of between 2.0 and 3.0.
The current standard of care in Ontario for patients on long-term OAT is laboratory-based INR determination with management carried out by primary care physicians or anticoagulation clinics (ACCs). Patients also regularly visit a hospital or community-based facility to provide a venous blood samples (venipuncture) that are then sent to a laboratory for INR analysis.
Experts, however, have commented that there may be under-utilization of OAT due to patient factors, physician factors, or regional practice variations and that sub-optimal patient management may also occur. There is currently no population-based Ontario data to permit the assessment of patient care, but recent systematic reviews have estimated that less that 50% of patients receive OAT on a routine basis and that patients are in the therapeutic range only 64% of the time.
Overview of POC INR Devices
POC INR devices offer an alternative to laboratory-based testing and venipuncture, enabling INR determination from a fingerstick sample of whole blood. Independent evaluations have shown POC devices to have an acceptable level of precision. They permit INR results to be determined immediately, allowing for more rapid medication adjustments.
POC devices can be used in a variety of settings including physician offices, ACCs, long-term care facilities, pharmacies, or by the patients themselves through self-testing (PST) or self-management (PSM) techniques. With PST, patients measure their INR values and then contact their physician for instructions on dose adjustment, whereas with PSM, patients adjust the medication themselves based on pre-set algorithms. These models are not suitable for all patients and require the identification and education of suitable candidates.
Potential advantages of POC devices include improved convenience to patients, better treatment compliance and satisfaction, more frequent monitoring and fewer thromboembolic and hemorrhagic complications. Potential disadvantages of the device include the tendency to underestimate high INR values and overestimate low INR values, low thromboplastin sensitivity, inability to calculate a mean normal PT, and errors in INR determination in patients with antiphospholipid antibodies with certain instruments. Although treatment satisfaction and quality of life (QoL) may improve with POC INR monitoring, some patients may experience increased anxiety or preoccupation with their disease with these strategies.
Evidence-Based Analysis Methods
Research Questions
1. Effectiveness
Does POC INR monitoring improve clinical outcomes in various settings compared to standard laboratory-based testing?
Does POC INR monitoring impact patient satisfaction, QoL, compliance, acceptability, convenience compared to standard laboratory-based INR determination?
Settings include primary care settings with use of POC INR devices by general practitioners or nurses, ACCs, pharmacies, long-term care homes, and use by the patient either for PST or PSM.
2. Cost-effectiveness
What is the cost-effectiveness of POC INR monitoring devices in various settings compared to standard laboratory-based INR determination?
Inclusion Criteria
English-language RCTs, systematic reviews, and meta-analyses
Publication dates: 1996 to November 25, 2008
Population: patients on OAT
Intervention: anticoagulation monitoring by POC INR device in any setting including anticoagulation clinic, primary care (general practitioner or nurse), pharmacy, long-term care facility, PST, PSM or any other POC INR strategy
Minimum sample size: 50 patients Minimum follow-up period: 3 months
Comparator: usual care defined as venipuncture blood draw for an INR laboratory test and management provided by an ACC or individual practitioner
Outcomes: Hemorrhagic events, thromboembolic events, all-cause mortality, anticoagulation control as assessed by proportion of time or values in the therapeutic range, patient reported outcomes including satisfaction, QoL, compliance, acceptability, convenience
Exclusion criteria
Non-RCTs, before-after studies, quasi-experimental studies, observational studies, case reports, case series, editorials, letters, non-systematic reviews, conference proceedings, abstracts, non-English articles, duplicate publications
Studies where POC INR devices were compared to laboratory testing to assess test accuracy
Studies where the POC INR results were not used to guide patient management
Method of Review
A search of electronic databases (OVID MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library, and the International Agency for Health Technology Assessment [INAHTA] database) was undertaken to identify evidence published from January 1, 1998 to November 25, 2008. Studies meeting the inclusion criteria were selected from the search results. Reference lists of selected articles were also checked for relevant studies.
Summary of Findings
Five existing reviews and 22 articles describing 17 unique RCTs met the inclusion criteria. Three RCTs examined POC INR monitoring devices with PST strategies, 11 RCTs examined PSM strategies, one RCT included both PST and PSM strategies and two RCTs examined the use of POC INR monitoring devices by health care professionals.
Anticoagulation Control
Anticoagulation control is measured by the percentage of time INR is within the therapeutic range or by the percentage of INR values in the therapeutic range. Due to the differing methodologies and reporting structures used, it was deemed inappropriate to combine the data and estimate whether the difference between groups would be significant. Instead, the results of individual studies were weighted by the number of person-years of observation and then pooled to calculate a summary measure.
Across most studies, patients in the intervention groups tended to have a higher percentage of time and values in the therapeutic target range in comparison to control patients. When the percentage of time in the therapeutic range was pooled across studies and weighted by the number of person-years of observation, the difference between the intervention and control groups was 4.2% for PSM, 7.2% for PST and 6.1% for POC use by health care practitioners. Overall, intervention patients were in the target range 69% of the time and control patients were in the therapeutic target range 64% of the time leading to an overall difference between groups of roughly 5%.
Major Complications and Deaths
There was no statistically significant difference in the number of major hemorrhagic events between patients managed with POC INR monitoring devices and patients managed with standard laboratory testing (OR =0.74; 95% CI: 0.52- 1.04). This difference was non-significant for all POC strategies (PSM, PST, health care practitioner).
Patients managed with POC INR monitoring devices had significantly fewer thromboembolic events than usual care patients (OR =0.52; 95% CI: 0.37 - 0.74). When divided by POC strategy, PSM resulted in significantly fewer thromboembolic events than usual care (OR =0.46.; 95% CI: 0.29 - 0.72). The observed difference in thromboembolic events for PSM remained significant when the analysis was limited to major thromboembolic events (OR =0.40; 95% CI: 0.17 - 0.93), but was non-significant when the analysis was limited to minor thromboembolic events (OR =0.73; 95% CI: 0.08 - 7.01). PST and GP/Nurse strategies did not result in significant differences in thromboembolic events, however there were only a limited number of studies examining these interventions.
No statistically significant difference was observed in the number of deaths between POC intervention and usual care control groups (OR =0.67; 95% CI: 0.41 - 1.10). This difference was non-significant for all POC strategies. Only one study reported on survival with 10-year survival rate of 76.1% in the usual care control group compared to 84.5% in the PSM group (P=0.05).
Summary Results of Meta-Analyses of Major Complications and Deaths in POC INR Monitoring Studies
Patient Satisfaction and Quality of Life
Quality of life measures were reported in eight studies comparing POC INR monitoring to standard laboratory testing using a variety of measurement tools. It was thus not possible to calculate a quantitative summary measure. The majority of studies reported favourable impacts of POC INR monitoring on QoL and found better treatment satisfaction with POC monitoring. Results from a pre-analysis patient and caregiver focus group conducted in Ontario also indicated improved patient QoL with POC monitoring.
Quality of the Evidence
Studies varied with regard to patient eligibility, baseline patient characteristics, follow-up duration, and withdrawal rates. Differential drop-out rates were observed such that the POC intervention groups tended to have a larger number of patients who withdrew. There was a lack of consistency in the definitions and reporting for OAT control and definitions of adverse events. In most studies, the intervention group received more education on the use of warfarin and performed more frequent INR testing, which may have overestimated the effect of the POC intervention. Patient selection and eligibility criteria were not always fully described and it is likely that the majority of the PST/PSM trials included a highly motivated patient population. Lastly, a large number of trials were also sponsored by industry.
Despite the observed heterogeneity among studies, there was a general consensus in findings that POC INR monitoring devices have beneficial impacts on the risk of thromboembolic events, anticoagulation control and patient satisfaction and QoL (ES Table 2).
GRADE Quality of the Evidence on POC INR Monitoring Studies
CI refers to confidence interval; Interv, intervention; OR, odds ratio; RCT, randomized controlled trial.
Economic Analysis
Using a 5-year Markov model, the health and economic outcomes associated with four different anticoagulation management approaches were evaluated:
Standard care: consisting of a laboratory test with a venipuncture blood draw for an INR;
Healthcare staff testing: consisting of a test with a POC INR device in a medical clinic comprised of healthcare staff such as pharmacists, nurses, and physicians following protocol to manage OAT;
PST: patient self-testing using a POC INR device and phoning in results to an ACC or family physician; and
PSM: patient self-managing using a POC INR device and self-adjustment of OAT according to a standardized protocol. Patients may also phone in to a medical office for guidance.
The primary analytic perspective was that of the MOHLTC. Only direct medical costs were considered and the time horizon of the model was five years - the serviceable life of a POC device.
From the results of the economic analysis, it was found that POC strategies are cost-effective compared to traditional INR laboratory testing. In particular, the healthcare staff testing strategy can derive potential cost savings from the use of one device for multiple patients. The PSM strategy, however, seems to be the most cost-effective method i.e. patients are more inclined to adjust their INRs more readily (as opposed to allowing INRs to fall out of range).
Considerations for Ontario Health System
Although the use of POC devices continues to diffuse throughout Ontario, not all OAT patients are suitable or have the ability to practice PST/PSM. The use of POC is currently concentrated at the institutional setting, including hospitals, ACCs, long-term care facilities, physician offices and pharmacies, and is much less commonly used at the patient level. It is, however, estimated that 24% of OAT patients (representing approximately 32,000 patients in Ontario), would be suitable candidates for PST/PSM strategies and willing to use a POC device.
There are several barriers to the use and implementation of POC INR monitoring devices, including factors such as lack of physician familiarity with the devices, resistance to changing established laboratory-based methods, lack of an approach for identifying suitable patients and inadequate resources for effective patient education and training. Issues of cost and insufficient reimbursement strategies may also hinder implementation and effective quality assurance programs would need to be developed to ensure that INR measurements are accurate and precise.
For a select group of patients who are highly motivated and trained, PSM resulted in significantly fewer thromboembolic events compared to conventional laboratory-based INR testing. No significant differences were observed for major hemorrhages or all-cause mortality. PST and GP/Nurse use of POC strategies are just as effective as conventional laboratory-based INR testing for thromboembolic events, major hemorrhages, and all-cause mortality. POC strategies may also result in better OAT control as measured by the proportion of time INR is in the therapeutic range and there appears to be beneficial impacts on patient satisfaction and QoL. The use of POC devices should factor in patient suitability, patient education and training, health system constraints, and affordability.
anticoagulants, International Normalized Ratio, point-of-care, self-monitoring, warfarin.
PMCID: PMC3377545  PMID: 23074516
6.  Practice nursed-based, individual and video-assisted patient education in oral anticoagulation - Protocol of a cluster-randomized controlled trial 
BMC Family Practice  2011;12:17.
Managing oral anticoagulant treatment (OAT) is a challenge for patients and primary care providers. It requires a high level of patient knowledge and adherence. Studies have shown that insufficient adherence and a low level of patient knowledge about OAT are primary causes for complications. This trial is the first to evaluate the long-term effects of a complex practice nurse-based patient education program in comparison to a patient brochure only.
Methods and design
This trial will be a cluster-randomized controlled trial in 22 general practices (GPs) recruiting 360 patients with OAT. GPs will be randomized into an intervention group or a control group. A baseline questionnaire will assess pre-existing knowledge about OAT. The patients in the intervention group will be educated by a complex education program which consists of a video, a brochure and individual training by a practice nurse. The video gives information about OAT, nutrition, and instructions about how to manage critical situations. The brochure repeats the content of the video. After 4 to 6 weeks, the intervention will be recapitulated. The control group will receive the brochure only. After 6 months, questionnaires will be used in both groups to assess patient knowledge about OAT as well as patients' subjective feelings of safety. Separately, we will evaluate patient records, looking for documented complications and the time spent in the therapeutic range.
This trial will start in January 2011. This trial will evaluate the long-term effectiveness of a video-assisted education program on patients with OAT in comparison to a patient information brochure. Most previous studies have evaluated knowledge directly after an educational intervention. Our trial will look for long-term differences in basic knowledge of OAT. We expect that our complex patient education program effectively increases long-term basic knowledge about OAT. Although the population of our study is too small to observe differences in adverse effects, we expect to discover differences in secondary outcomes, such as the time spent in the therapeutic range.
Trial registration
Deutsches Register Klinischer Studien (German Clinical Trials Register): DRKS00000586
Universal Trial Number (UTN U1111-1118-3464)
PMCID: PMC3089775  PMID: 21477372
7.  A non-experimental study of oral anticoagulation therapy initiation before and after national patient safety goals 
BMJ Open  2014;4(2):e003960.
The Joint Commission revised its National Patient Safety Goals (NPSGs) to include oral anticoagulation therapy (OAT) in 2008. We sought to examine the effect of including OAT in The Joint Commission's NPSGs on historically low rates of OAT initiation for individuals with incident atrial fibrillation (AF).
Southeastern state in the USA.
North Carolina State Health Plan claims data from 944 500 individuals enrolled between 1 January 2006 and 31 December 2010, supplemented with data from the Area Resource File and Online Survey, Certification and Reporting data network. We evaluated OAT initiation before and after the 2008 NPSGs revisions in a retrospective cohort new user design with an AF intervention group and two control groups: a positive control—patients estimated to be at very high risk of thromboembolism (mechanical heart valve and pulmonary embolism); and a negative control—patients with very low perceived risk of thromboembolism (paroxysmal AF). We developed multivariable models using a difference-in-difference parameterisation. Effects were estimated with generalised estimating equations.
Primary outcome measure
OAT initiation, a binary outcome defined as having a prescription drug claim for warfarin within 30 days of the index claim.
OAT initiation was low (26.8%) for eligible individuals with incident AF in 2006–2008 but increased after NPSGs implementation (31.7%, p=0.022). OAT initiation was high but decreased in the positive control group (67.5% vs 62.0%, p=0.003). Multivariate analysis resulted in a relative 11% (95% CI (4% to 18%), p<0.01) increase in OAT initiation for incident AF patients.
We document a substantial increase in guideline concordant OAT initiation in incident AF after the establishment of NPSGs, suggesting that regulatory healthcare agency initiatives can influence clinical practice.
PMCID: PMC3927813  PMID: 24525389
8.  Emergency reversal of anticoagulation: from theory to real use of prothrombin complex concentrates. A retrospective Italian experience 
Blood Transfusion  2012;10(1):87-94.
Prothrombin Complex Concentrates (PCC) are administered to normalise blood coagulation in patients receiving oral anticoagulant therapy (OAT). Rapid reversal of OAT is essential in case of major bleeding, internal haemorrhage or surgery.
The primary end-point was to evaluate whether PCC in our hospital were being used in compliance with international and national guidelines for the reversal of OAT on an emergency basis. The secondary end-point was to evaluate the efficacy and safety of PCC.
Materials and methods
All patients receiving OAT who required rapid reversal anticoagulation because they had to undergo emergency surgery or urgent invasive techniques following an overdose of oral anticoagulants were eligible for this retrospective observational study.
Forty-seven patients receiving OAT who needed rapid reverse of anticoagulation were enrolled in our study. The patients were divided in two groups: (i) group A (n=23), patients needed haemostatic treatment before neurosurgery after a head injury and (ii) group B (n=24), patients with critical haemorrhage because of an overdose of oral anticoagulants. The International Normalised Ratio (INR) was checked before and after infusion of the PCC. The mean INR in group A was 2.7 before and 1.43 after infusion of the PCC; in group B the mean INR of 6.58, before and 1.92 after drug infusion. The use of vitamin K, fresh-frozen plasma and red blood cells was also considered. During our study 22 patients died, but no adverse effects following PCC administration were recorded.
In our study three-factor-PCC was found to be effective and safe in rapidly reversing the effects of OAT, although it was not always administered in accordance with international or national guidelines. The dose, time of administration and monitoring often differed from those recommended. In the light of these findings, we advocate the use of single standard protocol to guide the correct use of PCC in each hospital ward.
PMCID: PMC3258994  PMID: 22044952
prothrombin complex concentrate; oral anticoagulant therapy; reversal of anticoagulation guidelines
9.  Identifying unprovoked thromboembolism patients at low risk for recurrence who can discontinue anticoagulant therapy 
Whether to continue oral anticoagulant therapy beyond 6 months after an “unprovoked” venous thromboembolism is controversial. We sought to determine clinical predictors to identify patients who are at low risk of recurrent venous thromboembolism who could safely discontinue oral anticoagulants.
In a multicentre prospective cohort study, 646 participants with a first, unprovoked major venous thromboembolism were enrolled over a 4-year period. Of these, 600 participants completed a mean 18-month follow-up in September 2006. We collected data for 69 potential predictors of recurrent venous thromboembolism while patients were taking oral anticoagulation therapy (5–7 months after initiation). During follow-up after discontinuing oral anticoagulation therapy, all episodes of suspected recurrent venous thromboembolism were independently adjudicated. We performed a multivariable analysis of predictor variables (p < 0.10) with high interobserver reliability to derive a clinical decision rule.
We identified 91 confirmed episodes of recurrent venous thromboembolism during follow-up after discontinuing oral anticoagulation therapy (annual risk 9.3%, 95% CI 7.7%–11.3%). Men had a 13.7% (95% CI 10.8%–17.0%) annual risk. There was no combination of clinical predictors that satisfied our criteria for identifying a low-risk subgroup of men. Fifty-two percent of women had 0 or 1 of the following characteristics: hyperpigmentation, edema or redness of either leg; D-dimer ≥ 250 μg/L while taking warfarin; body mass index ≥ 30 kg/m2; or age ≥ 65 years. These women had an annual risk of 1.6% (95% CI 0.3%–4.6%). Women who had 2 or more of these findings had an annual risk of 14.1% (95% CI 10.9%–17.3%).
Women with 0 or 1 risk factor may safely discontinue oral anticoagulant therapy after 6 months of therapy following a first unprovoked venous thromboembolism. This criterion does not apply to men. ( trial register number NCT00261014)
PMCID: PMC2518177  PMID: 18725614
10.  Patients' perspectives on self-testing of oral anticoagulation therapy: Content analysis of patients' internet blogs 
Patients on oral anticoagulant therapy (OAT) require regular testing of the prothrombin time (PT) and the international normalised ratio (INR) to monitor their blood coagulation level to avoid complications of either over or under coagulation. PT/INR can be tested by a healthcare professional or by the patient. The latter mode of the testing is known as patient self-testing or home testing. The objective of this study was to elicit patients' perspectives and experiences regarding PT/INR self-testing using portable coagulometer devices.
Internet blog text mining was used to collect 246 blog postings by 108 patients, mainly from the USA and the UK. The content of these qualitative data were analysed using XSight and NVivo software packages.
The key themes in relation to self-testing of OAT identified were as follows: Patient benefits reported were time saved, personal control, choice, travel reduction, cheaper testing, and peace of mind. Equipment issues included high costs, reliability, quality, and learning how to use the device. PT/INR issues focused on the frequency of testing, INR fluctuations and individual target (therapeutic) INR level. Other themes noted were INR testing at laboratories, the interactions with healthcare professionals in managing and testing OAT and insurance companies' involvement in acquiring the self-testing equipment. Social issues included the pain and stress of taking and testing for OAT.
Patients' blogs on PT/INR testing provide insightful information that can help in understanding the nature of the experiences and perspectives of patients on self-testing of OAT. The themes identified in this paper highlight the substantial complexities involved in self-testing programmes in the healthcare system. Thus, the issues elicited in this study are very valuable for all stakeholders involved in developing effective self-testing strategies in healthcare that are gaining considerable current momentum particularly for patients with chronic illness.
PMCID: PMC3045880  PMID: 21291542
11.  Study on Impact of Clinical Pharmacist’s Interventions in the Optimal Use of Oral Anticoagulants in Stroke Patients 
Anticoagulants are very useful medications but can also lead to haemorrhagic as well as thromboembolic complications when not used correctly or without proper medical attention. Anticoagulant’s complex pharmacology and pharmacokinetics contribute to its narrow margin of safety. Pharmacist’s unique knowledge of pharmacology, pharmacokinetics and interactions makes them well-suited to assist patients in maintaining safe and effective anticoagulation. Successful anticoagulation therapy implies fewer incidences of therapeutic failures and bleeding complications. The anticoagulation management service staffed by clinical pharmacists is a service established to monitor and manage oral and parenteral anticoagulants. In this research work, 40 patients each were included in the intervention and the control groups. In the intervention group, patient’s knowledge score on anticoagulation increased from an average of 5.6±3.2 to 13.8±0.94 (P=0.000) after clinical pharmacist’s counselling, whereas in the control group there was no significant improvement in patient’s baseline knowledge over the knowledge score at the end of the study (8.0±1.59 vs. 8.3±2.6) (P=0.218). In the intervention group, 73.45% of the international normalised ratio test results were within the therapeutic range, 8.45% supratherapeutic and 18.5% subtherapeutic during the 6 months data collection period. The corresponding data for the control group were 53.2 (P=0.000), 18.4 (P=0.000) and 28.4% (P=0.002), respectively. Forty four adverse drug reactions (ADRs) related to anticoagulants were identified in the intervention group as compared to 56 in the control group. These results revealed that the clinical pharmacist’s involvement in the anticoagulation management improved the therapeutic outcome of patients and demonstrate the benefits of clinical pharmacist guided anticoagulation clinics in India.
PMCID: PMC3719150  PMID: 23901161
Anticoagulation management in India; clinical pharmacist; international normalised ratio; thromboembolism; warfarin
12.  Needs and barriers to improve the collaboration in oral anticoagulant therapy: a qualitative study 
Oral anticoagulant therapy (OAT) involves many health care disciplines. Even though collaboration between care professionals is assumed to improve the quality of OAT, very little research has been done into the practice of OAT management to arrange and manage the collaboration. This study aims to identify the problems in collaboration experienced by the care professionals involved, the solutions they proposed to improve collaboration, and the barriers they encountered to the implementation of these solutions.
In the Netherlands, intensive follow-up of OAT is provided by specialized anticoagulant clinics (ACs). Sixty-eight semi-structured face-to-face interviews were conducted with 103 professionals working at an AC. These semi-structured interviews were transcribed verbatim and analysed inductively. Wagner's chronic care model (CCM) and Cabana's framework for improvement were used to categorize the results.
AC professionals experienced three main bottlenecks in collaboration: lack of knowledge (mostly of other professionals), lack of consensus on OAT, and limited information exchange between professionals. They mentioned several solutions to improve collaboration, especially solutions of CCM's decision support component (i.e. education, regular meetings, and agreements and protocols). Education is considered a prerequisite for the successful implementation of other proposed solutions such as developing a multidisciplinary protocol and changing the allocation of tasks. The potential of the health care organization to improve collaboration seemed to be underestimated by professionals. They experienced several barriers to the successful implementation of the proposed solutions. Most important barriers were the lack motivation of non-AC professionals and lack of time to establish collaboration.
This study revealed that the collaboration in OAT is limited by a lack of knowledge, a lack of consensus, and a limited information exchange. Education was identified as the best way to improve collaboration and considered a prerequisite for a successful implementation of other proposed solutions. Hence, the implementation sequence is of importance in order to improve the collaboration successfully. First step is to establish alignment regarding collaboration with all involved professionals to encounter the lack of motivation of non-AC professionals and lack of time.
PMCID: PMC3268100  PMID: 22192088
13.  Warfarin Anticoagulation Exacerbates the Risk of Hemorrhagic Transformation after rt-PA Treatment in Experimental Stroke: Therapeutic Potential of PCC 
PLoS ONE  2011;6(10):e26087.
Oral anticoagulant therapy (OAT) with warfarin is the standard of stroke prevention in patients with atrial fibrillation. Approximately 30% of patients with cardioembolic strokes are on OAT at the time of symptom onset. We investigated whether warfarin exacerbates the risk of thrombolysis-associated hemorrhagic transformation (HT) in a mouse model of ischemic stroke.
62 C57BL/6 mice were used for this study. To achieve effective anticoagulation, warfarin was administered orally. We performed right middle cerebral artery occlusion (MCAO) for 3 h and assessed functional deficit and HT blood volume after 24 h.
In non-anticoagulated mice, treatment with rt-PA (10 mg/kg i.v.) after 3 h MCAO led to a 5-fold higher degree of HT compared to vehicle-treated controls (4.0±0.5 µl vs. 0.8±0.1, p<0.001). Mice on warfarin revealed larger amounts of HT after rt-PA treatment in comparison to non-anticoagulated mice (9.2±3.2 µl vs. 2.8±1.0, p<0.05). The rapid reversal of anticoagulation by means of prothrombin complex concentrates (PCC, 100 IU/kg) at the end of the 3 h MCAO period, but prior to rt-PA administration, neutralized the exacerbated risk of HT as compared to sham-treated controls (3.8±0.7 µl vs. 15.0±3.8, p<0.001).
In view of the vastly increased risk of HT, it seems to be justified to withhold tPA therapy in effectively anticoagulated patients with acute ischemic stroke. The rapid reversal of anticoagulation with PCC prior to tPA application reduces the risk attributed to warfarin pretreatment and may constitute an interesting therapeutic option.
PMCID: PMC3198453  PMID: 22039437
14.  Inferior Vena Cava Filters 
Venous thromboembolism (VTE) remains a common disease with significant clinical impact upon our patients. Diagnostic challenges occur because of the nonspecific nature of the presenting symptoms. The advent of multidetector computed tomography, methods to stratify patients into VTE risks (low, intermediate, high) along with serological assays (D-dimers), have helped direct patients through proper workup and into conclusive diagnosis. In most cases, standard medical therapy for VTE is anticoagulation therapy (OAT). In situations where standard OAT is either contraindicated or complications result from that therapy, insertion of inferior vena cava (IVC) filters is considered. Recent reports suggest that although IVC filters are able to prevent pulmonary emboli (PE) in the short and intermediate term, there appear to be long-term consequences including excess recurrent deep venous thombosis (DVT and IVC/filter occlusions). Recognition of the time sequence of IVC filter benefits and complications has encouraged development of optional IVC filters, which can be left in place indefinitely or removed usually before certain time constraints. This article will attempt to address the timing of IVC filter placements to protect patients from significant PE.
PMCID: PMC3036373  PMID: 21326769
Venous; thrombosis; embolism; pulmonary; venae cavai; filters
15.  The association between chronic care management and the quality of thrombosis care 
The oral anticoagulant therapy (OAT), used to prevent thrombosis, is associated with substantial avoidable hospitalization.
Identify the associations between chronic care management and the quality of OAT as suggested by the chronic care model (CCM) of Wagner.
Regression analysis with data of 61 thrombosis clinics and inductive analysis with 63 interviews with health care professionals of 23 thrombosis clinics.
Results show substantial differences between regions in the quality of thrombosis care and the CCM activities. However, the variation in quality of care was not associated with the differences in CCM activities. The inductive analysis indicates that there are problems in the cooperation between caregivers. Several preferred CCM activities (e.g., multidisciplinary protocol) as well as the barriers to implement these activities (e.g., conflicting interests) were put forward by the health care professionals.
It can be concluded that there is variation in quality of thrombosis care between regions. This variation could not be explained by the observed differences in CCM activities. However, fragmentation is a major source of inefficiency according to health care professionals. The paper concludes with suggestions to improve chronic care management for thrombosis.
PMCID: PMC3031809
quality of care; thrombosis; chronic care management; disease management; effectiveness
16.  Anticoagulation Management 
To perform safe invasive procedures on patients on anticoagulation therapy, management of the patient's anticoagulation status is mandatory. For patients on anticoagulation therapy, a risk analysis of both the procedural risk of bleeding as well as the risk to the patient from discontinuing anticoagulation needs to be performed. For procedures at low risk of bleeding, the procedure may be performed with little change to the patient's anticoagulation regimen. For procedures with significant bleeding risk, however, anticoagulation will need to be held or reversed. Patients at high risk for thromboembolic complications will require bridging therapy if anticoagulation is to be withheld. In this article, a logical assessment of bleeding risk in patients undergoing procedures is presented, and a review of anticoagulation and risk is discussed.
PMCID: PMC3324206  PMID: 22550377
Anticoagulation; heparin; warfarin; bleeding
17.  Vitamin E Serum Levels and Bleeding Risk in Patients Receiving Oral Anticoagulant Therapy: a Retrospective Cohort Study 
Hemorrhagic risk assessment is a crucial issue in patients with nonvalvular atrial fibrillation (NVAF) who are receiving oral anticoagulant therapy (OAT). Our aim was to analyze the relationship between vitamin E, which possesses anticoagulant properties, and bleeding events in NVAF patients.
Methods and Results
In this retrospective observational study we analyzed baseline serum cholesterol‐adjusted vitamin E (vit E/chol) levels in 566 consecutive patients (59% males, mean age 73.6 years) receiving OAT followed up for a mean time of 22 months. Mean time in therapeutic INR range (TTR) was 64%. The overall incidence rate of any bleeding event was 9.2/100 person‐years. Compared to patients who did not bleed, those who experienced bleeding events (n=92, 73 minor and 15 major bleedings and 4 cerebral hemorrhages according to International Society on Thrombosis and Haemostasis [ISTH] ) classification) showed a significant difference for history of coronary heart disease (P=0.039), HAS‐BLED score (P=0.002), and vit E/chol levels (P<0.001). Higher vit E/chol serum levels were found in patients who bled compared to those who did not (5.27±1.93 versus 4.48±1.97 μmol/cholesterol; P<0.001), with a progressive increase from minor (5.16±1.91 μmol/mmol cholesterol, P=0.006) to major bleedings (5.72±2.0 μmol/mmol cholesterol, P=0.008). A Cox proportional hazard model demonstrated that serum vit E/chol quartiles (global P=0.0189) and HAS‐BLED scores (P=0.005) predicted bleeding events.
In a NVAF population being treated with warfarin, serum vitamin E predicted hemorrhagic events. Further study is necessary to see if the relationship between serum levels of vitamin E and bleeding is still maintained with the use of new anticoagulants.
Clinical Trial Registration
URL: Unique identifier NCT01882114.
PMCID: PMC3886776  PMID: 24166490
anticoagulation; atrial fibrillation; bleeding; tocopherol
18.  Triple antithrombotic therapy in patients with atrial fibrillation undergoing coronary artery stenting: hovering among bleeding risk, thromboembolic events, and stent thrombosis 
Thrombosis Journal  2012;10:22.
Dual antiplatelet treatment with aspirin and clopidogrel is the antithrombotic treatment recommended after an acute coronary syndrome and/or coronary artery stenting. The evidence for optimal antiplatelet therapy for patients, in whom long-term treatment oral anticoagulation is mandatory, is however scarce. To evaluate the safety and efficacy of the various antithrombotic strategies adopted in this population, we reviewed the available evidence on the management of patients receiving oral anticoagulation, such as a vitamin-k-antagonists, referred for coronary artery stenting.
Atrial fibrillation is the most frequent indication for oral anticoagulation. The need of starting antiplatelet therapy in this clinical scenario raises concerns about the combination to choose: triple therapy with warfarin, aspirin, and a thienopyridine being the most frequent and advised. The safety of this regimen appeared suboptimal because of an increased risk in hemorrhagic complications. On the other hand, the combination of oral anticoagulation and an antiplatelet agent is suboptimal in preventing thromboembolic events and stent thrombosis; dual antiplatelet therapy may be considered only when a high hemorrhagic risk and low thromboembolic risk are perceived. Indeed, the need for prolonged multiple-drug antithrombotic therapy increases the bleeding risks when drug eluting stents are used.
Since current evidence derives mainly from small, single-center and retrospective studies, large-scale prospective multicenter studies are urgently needed.
PMCID: PMC3502192  PMID: 23075316
Atrial fibrillation; Percutaneous coronary intervention; Stent; Warfarin; Antiplatelet drugs
19.  Potentially avoidable inpatient nights among warfarin receiving patients; an audit of a single university teaching hospital 
BMC Research Notes  2009;2:41.
Warfarin is an oral anticoagulant (OAT) that needs active management to ensure therapeutic range. Initial management is often carried out as an inpatient, though not requiring inpatient facilities. This mismatch results in financial costs which could be directed more efficaciously. The extent of this has previously been unknown. Here we aim to calculate the potential number of bed nights which may be saved among those being dose optimized as inpatients and examine associated factors.
A 6 week prospective audit of inpatients receiving OAT, at Cork University Hospital, was carried out. The study period was from 11th June 2007 to 20th July 2007. Data was collected from patient's medications prescription charts, medical record files, and computerised haematology laboratory records. The indications for OAT, the patient laboratory coagulation results and therapeutic intervals along with patient demographics were analysed. The level of potentially avoidable inpatient nights in those receiving OAT in hospital was calculated and the potential cost savings quantified. Potential avoidable bed nights were defined as patients remaining in hospital for the purpose of optimizing OAT dosage, while receiving subtherapeutic or therapeutic OAT (being titred up to therapeutic levels) and co-administered covering low molecular weight heparin, and requiring no other active care. The average cost of €638 was taken as the per night hospital stay cost for a non-Intensive Care bed. Ethical approval was granted from the Ethical Committee of the Cork Teaching Hospitals, Cork, Ireland.
A total of 158 patients were included in the audit. There was 94 men (59.4%) and 64 women (40.6%). The mean age was 67.8 years, with a median age of 70 years.
Atrial Fibrillation (43%, n = 70), followed by aortic valve replacement (15%, n = 23) and pulmonary emboli (11%, n = 18) were the commonest reasons for prescribing OAT. 54% had previously been prescribed OAT prior to current admission.
It was confirmed that, there are potentially avoidable nights in patients receiving OAT. The majority of this group were those being commenced on OAT for the first time (p = 0.00002), in the specialities of Cardiology, Cardiothoracic surgery and Care of the Elderly. The potential number of bed nights to be saved is 13 per week for the hospital or 1.1 bed nights per 10,000 general hospital admissions. These were predominantly weekday nights. The estimated cost of avoidable inpatient OAT dose optimization was approximately €8300 per week.
With rising costs and the increasing demands for acute hospital beds, alterations to inpatient management for this group of patients should be considered. Alternatives include increasing the size of current anticoagulation clinics, introduction of POCT (point of care testing) devices and increased GP management. POCT can be justified based upon the publication by Gardiner et al, who showed that 87% of patients find self testing straightforward, 87% were confident in the result they obtained using the devices and 77% preferred self testing.
PMCID: PMC2657894  PMID: 19284662
20.  EDUC’AVK: Reduction of Oral Anticoagulant-related Adverse Events After Patient Education: A Prospective Multicenter Open Randomized Study 
Journal of General Internal Medicine  2008;23(9):1441-1446.
Long-term oral anticoagulation treatment is associated with potential morbidity. Insufficient patient education is linked to poorly controlled anticoagulation. However the impact of a specific educational program on anticoagulation related morbidity remains unknown.
To evaluate the effect of an oral anticoagulation patient education program in reducing both hemorrhagic and recurrent thrombotic complications.
We conducted a prospective, multicenter open randomized study, comparing an interventional group who received a specific oral anticoagulation treatment educational program with a control group. Eligible patients were older than 18 and diagnosed as having deep vein thrombosis or pulmonary embolism requiring therapy with a vitamin K antagonist for 3 months or more. Our primary outcome was the occurrence of hemorrhagic or thromboembolic events.
During the 3-month follow-up the main outcome criteria were observed 20 times (6.6% of patients), 5 (3.1%) in the experimental and 15 (10.6%) in the control group. Consequently, in multivariate analysis, the cumulative risk reduction in the experimental group was statistically significant (OR 0.25, 95% CI 0.1 – 0.7,  < 0.01).
Patient education using an educational program reduced VKA-related adverse event rates.
PMCID: PMC2518037  PMID: 18566863
patient education; vitamin K antagonist
21.  Multivariate relationships between international normalized ratio and vitamin K-dependent coagulation-derived parameters in normal healthy donors and oral anticoagulant therapy patients 
Thrombosis Journal  2003;1:7.
Background and objectives
International Normalized Ratio (INR) is a world-wide routinely used factor in the monitoring of oral anticoagulation treatment (OAT). However, it was reported that other factors, e. g. factor II, may even better reflect therapeutic efficacy of OAT and, therefore, may be potentialy useful for OAT monitoring. The primary purpose of this study was to characterize the associations of INR with other vitamin K-dependent plasma proteins in a heterogenous group of individuals, including healthy donors, patients on OAT and patients not receiving OAT. The study aimed also at establishing the influence of co-morbid conditions (incl. accompanying diseases) and co-medications (incl. different intensity of OAT) on INR.
Design and Methods
Two hundred and three subjects were involved in the study. Of these, 35 were normal healthy donors (group I), 73 were patients on medication different than OAT (group II) and 95 were patients on stable oral anticoagulant (acenocoumarol) therapy lasting for at least half a year prior to the study. The values of INR and activated partial thromboplastin time (APTT) ratio, as well as activities of FII, FVII, FX, protein C, and concentration of prothrombin F1+2 fragments and fibrinogen were obtained for all subjects. In statistical evaluation, the uni- and multivariate analyses were employed and the regression equations describing the obtained associations were estimated.
Of the studied parameters, three (factors II, VII and X) appeared as very strong modulators of INR, protein C and prothrombin fragments F1+2 had moderate influence, whereas both APTT ratio and fibrinogen had no significant impact on INR variability. Due to collinearity and low tolerance of independent variables included in the multiple regression models, we routinely employed a ridge multiple regression model which compromises the minimal number of independent variables with the maximal overall determination coefficient. The best-fitted two-component model included FII and FVII activities and explained 90% of INR variability (compared to 93% in the 5-component model including all vitamin K-dependent proteins). Neither the presence of accompanying diseases nor the use of OAT nor any other medication (acetylsalicylic acid, statins, steroids, thyroxin) biased significantly these associations.
Among various vitamin K-dependent plasma proteins, the coagulation factors II, VII and X showed the most significant associations with INR. Of these variables, the two-component model, including factors II and VII, deserves special attention, as it largely explains the overall variability observed in INR estimates. The statistical power of this model is validated on virtue of the estimation that the revealed associations are rather universal and remain essentially unbiased by other compounding variables, including clinical status and medical treatment. Further, much broader population studies are needed to verify clinical usefulness of methods alternate or compounding to INR monitoring of OAT.
PMCID: PMC317378  PMID: 14969588
International Normalized Ratio (INR) of prothrombin time; clotting factors; protein C; prothrombin fragment F1+2; multivariate analysis
22.  Effects of oral anticoagulation with various INR levels in deep vein thrombosis cases 
In order to avoid the complications associated with thromboembolic disease, patients with this condition typically are placed on long-term anticoagulant therapy. This report compares bleeding complications in this patient population by level of achieved INR.
Materials and Methods
During the 6-year period between January 1997 and January 2003, 386 patients with venous thromboembolism of the lower extremities were admitted to the Cardiovascular Surgery Outpatient Clinic of Alsancak State Hospital. Of the 386 patients, 198 (51.2%) were women, and the average age was 52.3 years. All diagnoses of venous thromboembolism were confirmed by means of Doppler ultrasonography. Further investigation showed occult neoplasms in 22 (5.6%) of the cases. We excluded the patients with occult disease, and the remaining 364 constituted our study population.
Oral anticoagulation was standardized at 6 months' duration in all cases. We divided the patients into two groups. Group I consisted of 192 patients (52.7%) with INR values between 1.9 and 2.5; Group II comprised 172 patients with INR values between 2.6 and 3.5. Complications in each group were assessed and compared. The minor hemorrhage rate was 1.04% in Group I and 4.06% in Group II. The major hemorrhage rate was also 1.04% in Group I and was 6.3% in Group II. We determined that the complication rates for both minor and major hemorrhage were significant in patients with INR values above 2.5.
Oral anticoagulation must be followed closely in patients with venous thromboembolism. Higher INR levels are associated with significant increases in hemorrhage and associated complications. INR values of 2.0 to 2.5 are sufficient for long-term anticoagulant therapy, ensuring ideal anticoagulation levels and minimizing the complication rate.
PMCID: PMC384377  PMID: 14975176
Deep venous thrombosis; Warfarin; INR; risk of hemorrhage
23.  Warfarin-related intraventricular hemorrhage 
Neurology  2011;77(20):1840-1846.
Oral anticoagulation therapy (OAT) with warfarin increases mortality and disability after intracerebral hemorrhage (ICH), the result of increased ICH volume and risk of hematoma expansion. We investigated whether OAT also influences risk of development of intraventricular hemorrhage (IVH), the volume of IVH and IVH expansion, and whether IVH is a substantive mediator of the overall effect of OAT on ICH outcome.
We performed a retrospective analysis of a prospectively collected single-center cohort of 1,879 consecutive ICH cases (796 lobar, 865 deep, 153 cerebellar, 15 multiple location, 50 primary IVH) from 1999 to 2009. ICH and IVH volumes at presentation, as well as hematoma expansion (>33% or >6 mL increase) and IVH expansion (>2 mL increase), were determined using established semiautomated methods. Outcome was assessed at 90 days using either the modified Rankin Scale or Glasgow Outcome Scale.
Warfarin use was associated with IVH risk, IVH volume at presentation, and IVH expansion in both lobar and deep ICH (all p < 0.05) in a dose-response relationship with international normalized ratio. Warfarin was associated with poor outcome in both lobar and deep ICH (p < 0.01), and >95% of this effect was accounted for by baseline ICH and IVH volumes, as well as ICH and IVH expansion.
Warfarin increases IVH volume and risk of IVH expansion in lobar and deep ICH. These findings (along with effects on ICH volume and expansion) likely represent the mechanisms by which anticoagulation worsens ICH functional outcome.
PMCID: PMC3233208  PMID: 22049204
24.  The Role of Anticoagulation Clinics in the Era of New Oral Anticoagulants 
Thrombosis  2012;2012:835356.
Anticoagulation Clinics (ACs) are services specialized in management of patients on anticoagulant treatment. At present, ACs manage patients chiefly on antivitamin K antagonists (AVKs), but patient population has already changed in the last few years, because of an increase of treatments with other anticoagulant drugs, which require different management systems. The strong increase in the number of patients at AC, mainly on long-term treatment, has determined the development of web management, through telemedicine systems, improving the quality of life and maintaining the same clinical quality levels. New oral anticoagulants (NOAs) have shown to be as effective as AVK antagonists in stroke prevention in atrial fibrillation and for treatment of venous thromboembolism in addition to VTE prophylaxis in orthopaedic surgery, when administered at a fixed dose, but patient adherence and compliance are crucial for good quality treatment. At present, lacking data from the real world, an oversimplification of treatment with NOAs could cause unjustified risks for patients and also a possible future underuse of good drugs. For these reasons the vigilance must be high and ACs can have a crucial role in defining which is the best management for NOA patients and how to do it, as it happened for AVKs.
PMCID: PMC3477769  PMID: 23097696
25.  Atrial Fibrillation Ablation without Interruption of Anticoagulation 
Atrial fibrillation (AF) can be cured by pulmonary vein antrum isolation (PVAI) in a substantial proportion of patients. The high efficacy of PVAI is partially undermined by a small but concrete periprocedural risk of complications, such as thromboembolic events and bleeding. A correct management of anticoagulation is essential to prevent such complications. Performing PVAI without interruption of oral anticoagulation has been demonstrated feasible by our group in previous studies. Recently, we reported that continuation of therapeutic warfarin during radiofrequency catheter ablation consistently reduces the risk of periprocedural stroke/transient ischemic attack without increasing the risk of hemorrhagic events. Of note, interrupting warfarin anticoagulation may actually increase the risk of stroke even when bridged with heparin. The latter strategy is also associated with an increased risk of minor bleeding. With regard to major bleeding, we found no significant difference between patients with a therapeutic INR and those who were bridged with heparin. Therefore, continuation of therapeutic warfarin during ablation of AF appears to be the best anticoagulation strategy. In this paper we summarize our experience with AF ablation without interruption of anticoagulation.
PMCID: PMC3090717  PMID: 21577267

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