Discontinuation Of Oral Anticoagulation Therapy Research Articles

Importance of attributes and willingness to pay for oral anticoagulant therapy in patients with atrial fibrillation in China: A discrete choice experiment.

Adherence to oral anticoagulant therapy in patients with atrial fibrillation (AF) in China is low. Patient preference, one of the main reasons for discontinuation of oral anticoagulant therapy, is an unfamiliar concept in China. A discrete choice experiment (DCE) was conducted to quantify patient preference on 7 attributes of oral anticoagulant therapy: antidote (yes/no), food-drug interaction (yes/no), frequency of blood monitoring (no need, every 6/3/1 month[s]), risk of nonfatal major bleeding (0.7/3.1/5.5/7.8[%]), risk of nonfatal stroke (ischemic/hemorrhagic) or systemic embolism (0.6/3.2/5.8/8.4[%]), risk of nonfatal acute myocardial infarction (AMI) (0.2/1.0/1.8/2.5[%]), and monthly out-of-pocket cost (0/120/240/360 RMB) (0 to 56 USD). A total of 16 scenarios were generated by using D-Efficient design and were randomly divided into 2 blocks. Eligible patients were recruited and interviewed from outpatient and inpatient settings of 2 public hospitals in Beijing and Shenzhen, respectively. Patients were presented with 8 scenarios and asked to select 1 of 3 options: 2 unlabeled hypothetical treatments and 1 opt-out option. Mixed logit regression model was used for estimating patients' preferences of attributes of oral anticoagulants and willingness to pay (WTP) with adjustments for age, sex, education level, income level, city, self-evaluated health score, histories of cardiovascular disease/other vascular disease/any stroke/any bleeding, and use of anticoagulant/antiplatelet therapy. A total of 506 patients were recruited between May 2018 and December 2019 (mean age 70.3 years, 42.1% women). Patients were mainly concerned about the risks of AMI (β: -1.03; 95% CI: -1.31, -0.75; p < 0.001), stroke or systemic embolism (β: -0.81; 95% CI: -0.90, -0.73; p < 0.001), and major bleeding (β: -0.69; 95% CI: -0.78, -0.60; p < 0.001) and were willing to pay more, from up to 798 RMB to 536 RMB (124 to 83 USD) monthly. The least concerning attribute was frequency of blood monitoring (β: -0.31; 95% CI: -0.39, -0.24; p < 0.001). Patients had more concerns about food-drug interactions even exceeding preferences on the 3 risks, if they had a history of stroke or bleeding (β: -2.47; 95% CI: -3.92, -1.02; p < 0.001), recruited from Beijing (β: -1.82; 95% CI: -2.56, -1.07; p < 0.001), or men (β: -0.96; 95% CI: -1.36, -0.56; p < 0.001). Patients with lower educational attainment or lower income weighted all attributes lower, and their WTP for incremental efficacy and safety was minimal. Since the patients were recruited from 2 major hospitals from developed cities in China, further studies with better representative samples would be needed. Patients with AF in China were mainly concerned about the safety and effectiveness of oral anticoagulant therapy. The preference weighting on food-drug interaction varied widely. Patients with lower educational attainment or income levels and less experience of bleeding or stroke had more reservations about paying for oral anticoagulant therapies with superior efficacy, safety, and convenience of use.

Discontinuation of oral anticoagulation therapy after successful atrial fibrillation ablation: A systematic review and meta-analysis of prospective studies.

The safety of discontinuing oral anticoagulant (OAC) therapy after atrial fibrillation (AF) ablation remains controversial. A meta-analysis was performed to assess the safety and feasibility of discontinuing OAC therapy after successful AF ablation. PubMed and Embase were searched up to October 2020 for prospective cohort studies that reported the risk of thromboembolism (TE) after successful AF ablation in off-OAC and on-OAC groups. The primary outcome was the incidence of TE events. The Mantel-Haenszel method with random-effects modeling was used to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). A total of 11,148 patients (7,160 in the off-OAC group and 3,988 in the on-OAC group) from 10 studies were included to meta-analysis. No significant difference in TE between both groups was observed (OR, 0.73; 95%CI, 0.51-1.05; I2 = 0.0%). The risk of major bleeding in off-OAC group was significantly lower compared to the on-OAC group (OR, 0.18; 95%CI, 0.07-0.51; I2 = 51.7%). Our study suggests that it may be safe to discontinue OAC therapy in patients after successful AF ablation. Additionally, an increased risk of major bleeding was observed in patients on OAC. However, the results of this meta-analysis should be interpreted with caution because of the heterogeneity among the included study designs. Large-scale and adequately powered randomized controlled trials are warranted to confirm these findings.

Discontinuation of anticoagulants after successful surgical ablation of atrial fibrillation.

The decision of whether to continue oral anticoagulation therapy (OAT) after successful surgical ablation of atrial fibrillation is challenging, and current guidelines provide no specific recommendations on whether or not it is safe to terminate OAT. Therefore, the aim of this study was to assess long-term outcomes in patients who either did or did not, receive OAT after surgical ablation of atrial fibrillation. In a prospective follow-up study, patients were included if surgical ablation of atrial fibrillation concomitantly with other cardiac surgery was done, between 2004 and 2018 at Aarhus University Hospital, Denmark. After 12 months, OAT was discontinued if: (a) sinus rhythm was documented by electrocardiogram, (b) atrial fibrillation was absent on 5-day Holter monitoring, (c) CHADS2 score ≤2, and (d) no other indications for OAT were present. Follow-up was ended in April 2019. A total of 560 patients underwent surgical ablation of which 436 patients reached the baseline at 12 months; 286 patients received OAT, and 150 had OAT discontinued. Survival analysis revealed no differences between the two groups (P = .723). Mean survival time in the group receiving OAT was 5.3 ± 3.3 years, compared to 5.1 ± 3.0 years in the group where OAT was discontinued (P = .784). There was no difference in major adverse cardiac and cerebrovascular events between the two groups (P = .846). Discontinuation of OAT is safe in patients with a CHADS2 score ≤2 following successful surgical ablation and left atrial appendage occlusion. This conclusion needs to be confirmed in randomized trials.

P6559Long-term follow-up and outcomes of patients with discontinuation of oral anticoagulant therapy after successful ablation procedures for atrial fibrillation

Abstract Background Oral anticoagulant therapy (OAT) is effective for preventing strokes in atrial fibrillation (AF) patients. Currently, there is controversy regarding the discontinuation of OATs in patients with ablation procedures to eliminate AF. Aim We investigated the incidence of major bleeding and ischemic strokes/systemic embolisms in low-risk patients that discontinued OATs after successful AF ablation procedures. Methods Of 330 consecutive patients that underwent AF ablation procedures and were prescribed one of the direct oral anticoagulants or warfarin, 207 AF patients (158 men, mean age 61±11 years) who discontinued OATs three months after the procedure were enrolled. The average CHADS2 and HAS-BLED scores were 1.0±0.9 and 1.2±1.0, respectively, which meant that most patients had a low risk for strokes. Results During follow-up, 31 patients (15%) had recurrences of AF. Those patients underwent a re-ablation procedure and then re-discontinued their OATs three months after the session. During a 60±13 months follow-up, major bleeding was observed in five patients (2.4%) and was associated with a higher HAS-BLED score (2.2±0.4 vs. 1.1±1.0, P=0.027). In contrast, none of the patients experienced ischemic strokes/systemic embolisms. Conclusions This prospective study demonstrated that in patients with successful ablation procedures and low risk scores for AF management, OATs could be discontinued three months after the procedure. Unnecessary continuation of OATs may increase the incidence of major bleeding during the follow-up.

The safety of discontinuation of oral anticoagulation therapy after apparently successful atrial fibrillation ablation: a report from the Chinese Atrial Fibrillation Registry study.

We aimed to investigate the safety of discontinuing oral anticoagulation (OAC) therapy after apparently successful atrial fibrillation (AF) ablation, using data from the Chinese Atrial Fibrillation Registry study. We identified 4512 consecutive patients who underwent successful AF ablation between August 2011 and December 2017. Of them, 3149 discontinued OAC 3 months post-ablation (Off-OAC group) and 1363 continued OAC beyond this period (On-OAC group). Regular follow-up examinations were undertaken to detect AF recurrence, monitor OAC therapy, and measure clinical outcomes. Primary outcomes included thromboembolic and major bleeding (MB) events experienced beyond 3 months after ablation. Low thromboembolic and MB event rates were noted in the on-treatment analysis. The incidence rates for thromboembolism were 0.54 [95% confidence interval (CI) 0.39-0.76] and 0.86 (95% CI 0.56-1.30) per 100 patient-years, and that for MB events were 0.19 (95% CI 0.11-0.34) and 0.35 (95% CI 0.18-0.67) per 100 patient-years, for the Off-OAC and On-OAC groups over mean follow-up periods of 24.2 ± 14.7 and 23.0 ± 13.6 months, respectively. Similar results were observed in the intention-to-treat analysis. Previous history of ischaemic stroke (IS)/transient ischaemic attack (TIA)/systemic embolism (SE) [hazard ratio (HR) 3.40, 95% CI 1.92-6.02; P < 0.01] and diabetes mellitus (HR 2.06, 95% CI 1.20-3.55, P = 0.01) were independently associated with thromboembolic events, while OAC discontinuation (HR 0.71, 95% CI 0.41-1.23, P = 0.21) remained insignificant in multivariable analysis. This study suggests that it may be safe to discontinue OAC in post-ablation patients under diligent monitoring, in the absence of AF recurrence, history of IS/TIA/SE, and diabetes mellitus. However, further large-scale randomized trials are required to confirm this. Chinese Clinical Trial Registry ChiCTR-OCH-13003729. URL: http://www.chictr.org.cn/showproj.aspx?proj=5831.

Residual pulmonary embolism as a predictor for recurrence after a first unprovoked episode: Results from the REVERSE cohort study

BackgroundThe optimal duration of oral anticoagulant therapy after a first, unprovoked venous thromboembolism is controversial due to tightly balanced risks and benefits of indefinite anticoagulation. Risk stratification tools may assist in decision making. ObjectivesWe sought to determine the relationship between residual pulmonary embolism assessed by baseline ventilation-perfusion scan after completion of 5–7months of oral anticoagulant therapy and the risk of recurrent venous thromboembolism in patients with the first episode of unprovoked pulmonary embolism. MethodsWe conducted a multicentre prospective cohort study of participants with a first, unprovoked venous thromboembolism enrolled after the completion of 5–7months of oral anticoagulation therapy. The participants completed a mean 18-month follow-up. Participants with pulmonary embolism had baseline ventilation-perfusion scan before discontinuation of oral anticoagulant therapy and the percentage of vascular obstruction on baseline ventilation-perfusion scan was determined. During follow-up after discontinuation of oral anticoagulant therapy, all episodes of suspected recurrent venous thromboembolism were independently adjudicated with reference to baseline imaging. Measurements and main resultsDuring follow-up, 24 of 239 (10.0%) participants with an index event of isolated pulmonary embolism or pulmonary embolism associated with deep vein thrombosis and central assessment of percentage of vascular obstruction on baseline ventilation-perfusion scan had confirmed recurrent venous thromboembolism. As compared to participants with no residual pulmonary embolism on baseline ventilation-perfusion scan, the hazard ratio for recurrent venous thromboembolism was 2.0 (95% CI 0.5–7.3) for participants with percentage of vascular obstruction of 0.1%–4.9%, 2.1 (95% CI 0.5–7.8) for participants with percentage vascular obstruction of 5.0%–9.9% and 5.3 (95% CI 1.8–15.4) for participants with percentage vascular obstruction greater than or equal to 10%. ConclusionsResidual pulmonary embolism assessed by pulmonary vascular obstruction on baseline ventilation-perfusion performed after 5–7months of oral anticoagulant therapy for the first episode of unprovoked pulmonary embolism was associated with a statistically significant higher risk of subsequent recurrent venous thromboembolism. Percentage of pulmonary vascular obstruction assessment by ventilation-perfusion scans maybe a useful tool to help guide the duration of oral anticoagulant therapy after a first unprovoked pulmonary embolism. Trial registrationRegistered at www.clinicaltrials.gov identifier: NCT00261014.

Prediction of very late arrhythmia recurrence after radiofrequency catheter ablation of atrial fibrillation: The MB-LATER clinical score

Reliable prediction of very late recurrence of atrial fibrillation (VLRAF) occuring >12 months after catheter ablation (CA) in apparently “cured” patients could optimize long-term follow-up and modify decision-making regarding the discontinuation of oral anticoagulant therapy. In a single-centre cohort of consecutive patients post radiofrequency AFCA, we retrospectively derived a novel score for VLRAF prediction. Of 133 consecutive post AFCA patients (mean age 56.9 ± 11.8 years, 63.9% male, 69.2% with paroxysmal AF) who were arrhythmia-free at 12 months (excluding 3-month “blanking period”), 20 patients expirienced a VLRAF during a 29.1 ± 10.1-month follow-up, with a 3-year cumulative VLRAF rate of 31.1%. The MB-LATER score (Male, Bundle brunch block, Left atrium ≥47 mm, Type of AF [paroxysmal, persistent or long-standing persistent], and ER-AF = early recurrent AF), had better predictive ability for VLRAF (AUC 0.782) than the APPLE, ALARMc, BASE-AF2, CHADS2, CHA2DS2VASc or HATCH score (AUC 0.716, 0.671, 0.648, 0.552, 0.519 and 0.583, respectively), resulted in an improved net reclassification index (NRI) of 48.6–95.1% and better identified patients with subsequent VLRAF using decision-curve analysis (DCA). The MB-LATER score provides a readily available VLRAF risk assessment, and performs better than other scores. Validation of the MB-LATER score in other cohorts is underway.

Utility of Plasma D-dimer in Decision to Continue Anticoagulation Therapy Following Idiopathic Venous Thromboembolism

Evidence-Based Answer A single normal D-dimer at the time of the standard oral anticoagulation therapy (OAT) treatment period of 3-6 months is insufficient to predict recurrence of venous thromboembolism (VTE) because OAT may suppress D-dimer levels even in individuals at risk for recurrence (Strength of Recommendation (SOR) B). A negative D-dimer one month after discontinuation of OAT has a high negative predictive value for recurrent VTE, and supports the decision to permanently discontinue treatment (SOR A). Elevated D-dimer levels, either at the end of the recommended course of OAT or upon repeat in one month if the initial level is normal, predict recurrence of VTE and support the decision to resume OAT (SOR A).

Long-term oral anticoagulation for patients after successful catheter ablation of atrial fibrillation: is it necessary?

Catheter ablation for atrial fibrillation is an effective rhythm-control therapy for selected patients. Currently, it is unknown whether maintenance of sinus rhythm after atrial fibrillation ablation can reduce one's stroke risk. If so, this may potentially obviate the need to treat patients with long-term oral anticoagulation (OAC). This article reviews the available evidence and areas of uncertainty pertaining to this question. To date, no randomized trial data exist on this topic. Analyses from health administrative databases and observational registries suggested that atrial fibrillation patients who underwent catheter ablation had lower risk of stroke when compared with those who did not. Among patients who maintained sinus rhythm after ablation, low rates of stroke (<0.7% per year) were observed even after discontinuation of OAC therapy. These findings raise the possibility that successful catheter ablation may lower one's stroke risk to a point at which long-term OAC therapy is not obligatory. Whether successful atrial fibrillation ablation reduces one's stroke risk is unknown. Low stroke risks were reported by observational studies in patients who maintained sinus rhythm after ablation despite OAC cessation. High-quality, randomized trial data are needed to provide clarity on this key unanswered question.

D-dimer: a useful tool in gauging optimal duration of oral anticoagulant therapy?

BACKGROUND AND AIM OF THE STUDY Optimal duration of oral anticoagulant therapy (OAT) in idiopathic venous thromboembolism (VTE) is unknown. Indefinite OAT carries an unacceptable risk of major bleeding and prospective studies have demonstrated that OAT is no longer protective after its withdrawal. How to identify the patients at risk for recurrence? D-dimer is a marker of thrombin activity. Early prospective studies showed that elevated D-dimer levels after anticoagulation had a highly predictive value for a recurrent episode. Does D-dimer assay have a role in gauging the appropriate duration of anticoagulant therapy? The PROLONG study tries to answer this question. METHOD D-dimer assay was performed one month after stopping anticoagulation. Patiens with normal D-dimer levels did not resume anticoagulation while patients with elevated D-dimer levels were randomized to discontinue or resume anticoagulation. Study end-points was the composite of recurrent VTE and major bleeding during an average follow-up of 1.4 years. RESULTS The rate of recurrence is significantly higher in patients with elevated D-dimer levels who discontinued anticoagulation. Resuming anticoagulation in this cohort of patients markedly reduces recurrent events without increasing major bleeding. DISCUSSION AND CONCLUSIONS PROLONG study is provocative, because D-dimer assay is simple, thus not requiring dedicated laboratory facilities. D-dimer test has otherwise high sensitivity but low specificity in VTE diagnosis. Aspecifically elevated D-dimer levels are available in the elderly and the majority of patients included in the study were > 65 years old, thus introducing a possible selection bias. Nonetheless the results of the study are useful for the clinician. Prolongation of vitamin K antagonists in patients with elevated D-dimer levels one month after discontinuation of OAT for a first unprovoked episode of VTE results in a favourable risk-benefit relationship. Probably this conclusion is even more appropriate for young patients.

Delayed Complications of Tooth Extraction in Patients Taking Warfarin, Antibiotics, and Other Medications

Current published data support treating patients taking warfarin (Coumadin) in a routine manner. 1 Jeske A.H. Suchko G.D. Lack of scientific basis for routine discontinuation of oral anticoagulation therapy before dental treatment. J Am Dent Assoc. 2003; 134: 1492 Crossref PubMed Scopus (86) Google Scholar , 2 Campell J.H. Alvarado F. Murray R.A. Anticoagulation and minor oral surgery: Should the anticoagulation regiment be altered?. J Oral Maxillofac Surg. 2000; 58: 131 Abstract Full Text Full Text PDF PubMed Scopus (106) Google Scholar , 3 Scully C. Wolff A. Oral surgery in patients on anticoagulant therapy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002; 94: 57 Abstract Full Text Full Text PDF PubMed Scopus (130) Google Scholar First, one should obtain an international normalized ratio (INR) level and then consider the use of enoxaparin (Lovenox) as interim anticoagulant therapy or simply maintain standard warfarin dosage, depending on the complexity of the treatment plan. Combined with intraoperative modalities such as local anesthesia, including epinephrine, oxidized cellulose, gelatin sponges, and primary closure, successful outcomes are common.

Identifying Unprovoked Thromboembolism Patients at Low Risk for Recurrence Who Can Discontinue Anticoagulant Therapy

Conclusion: Oral anticoagulation therapy can be safely discontinued after 6 months in woman who have zero or one potential predictor of recurrent venous thromboembolism (VTE). Summary: Optimal duration of anticoagulation after unprovoked VTE is controversial. In this study the authors sought to identify clinical predictors to identify patients at low risk of VTE recurrence after discontinuation of oral anticoagulants. This was a multicenter prospective cohort study involving 646 patients with a first unprovoked major VTE. Patients were enrolled during a 4-year period, and 600 completed a mean 18-month follow-up. Data were collected for 16 potential predictors of recurrent VTE during the time patients were taking oral anticoagulation therapy (5 to 7 months after initiation). After discontinuation of oral anticoagulation therapy, patients were monitored for recurrent VTE. During follow-up, 91 confirmed episodes of recurrent VTE were identified (annual risk, 9.3%; 95% confidence interval [CI], 7.1%-11.3%). The annual risk for men was 13.7% (95% CI, 10.8%-17.0%). No combination of clinical predictors could identify a low-risk subgroup of men. Zero or one of the following characteristics were present in 52% of women: D-dimer level >250 mg/L while taking warfarin; body mass index >30 kg/m2; hyperpigmentation, edema, or redness of either leg; or age >65 years. Women with zero or one of these predictors had an annual risk of VTE recurrence of 1.6% (95% CI, 0.3%-4.6%). Women with two or more of these predictors had an annual risk of VTE recurrence of 14.1% (95% CI, 10.9%-17.3%). Comment: This study is consistent with the previously determined adverse effect of male sex on the recurrence of VTE (Lancet 2006;368:371-8). There are three major points here. First, identification of risk factors after 5 to 7 months of oral anticoagulation therapy is a strong predictor of recurrent VTE. Second, D-dimer levels after stopping oral anticoagulation may not be sufficient to identify patients at low risk of recurrence, whereas D-dimer levels while taking oral anticoagulation may be a strong predictor of recurrent VTE. The point is particularly interesting in that it allows more efficient care of patients. Stopping anticoagulation and testing D-dimer levels 1 month later and subsequently restarting anticoagulation therapy if necessary is impractical and exposes potentially high-risk patients to a period without anticoagulation. Finally, the authors identified a clinical decision rule that identifies women at low risk of VTE.

Elevated D-dimer levels predict recurrence in patients with idiopathic venous thromboembolism: a meta-analysis.

The evidence on the optimal duration of treatment in patients with an idiopathic venous thromboembolic event (VTE) is inconclusive. d-dimer testing to predict recurrent VTE has been evaluated in several studies. We performed a meta-analysis of studies of patients with idiopathic VTE treated with oral anticoagulation therapy (OAT) to assess the prognostic value of elevated D-dimer levels 1 month after discontinuation of OAT for VTE recurrence. The MEDLINE, EMBASE and Cochrane databases were searched to identify relevant studies. Studies were eligible for inclusion if they included patients with idiopathic VTE and in addition reported results for this group separately, had measured D-dimer approximately 1 month after discontinuation of OAT and had reported on recurrence of VTE. A random-effects model was used to pool study results. Data from four studies (1539 patients) were included in the current analysis. All studies reported on the number of recurrent events in the normal and elevated D-dimer groups. Overall, 125 of 751 patients (16.6%) with elevated D-dimer levels experienced recurrent VTE during the period of follow-up compared with 57 of 788 patients (7.2%) with normal D-dimer levels. Elevated D-dimer levels were significantly associated with recurrent VTE (odds ratio , 2.36; 95% CI, 1.65 to 3.36). Elevated d-dimer levels measured 1 month after discontinuation of OAT identify patients with idiopathic VTE at higher risk of recurrence.

Non-obstructive prosthetic aortic valve thrombosis presenting with acute myocardial infarction and stroke in a patient with inadequate low-molecular-weight heparin treatment. The unlucky patient and the (pseudo)prudent physician

Non-obstructive prosthetic valve thrombosis is a rare and underestimated complication in patients with left-sided mechanical heart valves. Systemic embolisation, mainly involving the cerebral circulation, often represents the first clinical manifestation. We report a case of multiple, successive embolizations in the coronary and cerebral circulation, presenting with an acute myocardial infarction and stroke in a patient with latent, non-obstructive thrombosis of a mechanical bileaflet aortic valve. Because of scheduled urological surgery, chronic vitamin K antagonist treatment had previously been discontinued and replaced with low-molecular-weight heparin, at inadequate dosage. Following coronary arteriography, brain computed tomography scan and transoesophageal echocardiography, thrombolysis was performed successfully. This case emphasises the utility of performing transoesophageal echocardiography routinely in the presence of ischaemic signs in patients with mechanical heart valves. In patients requiring discontinuation of oral anticoagulant therapy, accurate management and continuous monitoring of alternative medications are needed in order to avoid severe thromboembolic complications.

Cerebral venous sinus thrombosis as a recurrent thrombotic event in a patient with heterozygous prothrombin G20210A genotype after discontinuation of oral anticoagulation therapy: How long should we treat these patients with warfarin?

Cerebral venous sinus thrombosis is an uncommon condition with many clinical manifestations, and hereditary prothrombotic conditions such as factor Leiden V, deficiency of protein S, protein C and antithrombin III, as well as prothrombin gene mutation, may account for 10-15% of cases. To date, conflicting results have been reported for recurrent venous thrombosis in the patients with factor V Leiden and prothrombin G20210A mutation, since some studies have shown a higher risk for recurrent venous thrombosis in carriers of these two mutations than in non-carriers, and the last study showed higher risk only for carriers of double defect (homozygous or double heterozygous for this mutations). Case report is presented. We report a case of cerebral sinus thrombosis as a recurrent thrombotic event in a patient with heterozygous prothrombin G20210A genotype after discontinuation of oral anticoagulation therapy. Since many facts are controversial, the use of secondary prophylaxis for thrombosis in these patients is still a matter of debate without clear consensus recommendation. Data on the risk of recurrent thrombotic events in thrombophilic patient is insufficient. The main unclear question concerning these patients is: how long and whom should we treat with long-term anticoagulant therapy as secondary prophylaxis of DVT? The problem for practitioner is that we do not have guidelines and precise recommendations for secondary thromboprophylaxis in this or similar cases. This case is remarkable for its favorable and quick outcome and its rarity, because CSVT is an uncommon condition and heterozygous prothrombin G20210A genotype was only found predisposing factor for CSVT. Further studies of risk of recurrent venous thrombosis in patients with heterozygous prothrombin G20210A genotype with the larger sample size are required.

Use of low-molecular-weight heparin during dental extractions in a medicaid population.

Evidence-based guidelines recommend against discontinuation of oral anticoagulation therapy during most dental procedures because severe bleeding complications are rare and there is an increased risk for thromboembolic events in patients for whom warfarin therapy is interrupted. Although interruption of oral anticoagulation and bridge therapy with low-molecular- weight heparin (LMWH) may be indicated for high-risk individuals undergoing certain procedures, the use of LMWH in tooth extractions is expensive and often unnecessary. The purpose of this review was to identify and characterize procedural use of LMWH for dental extractions with respect to current consensus recommendations. The Idaho Medicaid pharmacy and medical claims database was queried to identify patients with a tooth extraction procedure between February 1, 1998, and January 31, 2005. Patients on warfarin therapy for 2 months before tooth extraction were identified as were claims for LMWH within 30 days before the procedure or 5 days after. Patient profiles were reviewed to determine number of extractions, rate of LMWH use, indication for anticoagulation, and associated drug costs. Of 55,260 Medicaid patients who had a tooth extraction, 518 (0.9%) had received warfarin for at least 2 consecutive months before the tooth extraction procedure. Of these, 31 patients (6%) received LMWH therapy at the time of extraction for a total of 35 procedures. All procedures selected for review carried a low bleeding risk, with an average of 1.3 teeth extracted per procedure. The indications for anticoagulation included 16 procedures (45.7%) involving patients with a history of a thromboembolic event more than 90 days before the procedure, 10 procedures (28.5%) involving patients with a prosthetic valve, 4 procedures (11.4%) involving anticoagulated patients with atrial fibrillation, and 5 procedures (14.2%) involving patients with a history of thromboembolism fewer than 3 months before the procedure. LMWH costs for these 35 extractions totaled $22,294, or an average of $637 per procedure or $474 per extracted tooth. Enoxaparin was used in all but 1 of the procedures, with an average 5-day supply (average 8 enoxaparin units) dispensed per procedure. The costs associated with the required additional drug monitoring, e.g., INR monitoring, were not included in this analysis. Although the overall number of dental procedures in anticoagulated patients using LMWH was small in our review, this inappropriate use resulted in avoidable costs to this Medicaid program.

Hemostatic Mouthwashes in Anticoagulated Patients Undergoing Dental Extraction

To evaluate the efficacy and safety of local acting hemostatic agents in patients who are undergoing dental extraction(s) and are taking oral anticoagulants. A search of MEDLINE (1966-July 2006), International Pharmaceutical Abstracts (1970-July 2006), and EMBASE (1966-July 2006) was conducted using the key terms anticoagulation, warfarin, hemostatic mouthwashes, epsilon aminocaproic acid, tranexamic acid, dental extraction, and oral surgery. Bibliographies of relevant papers were reviewed for additional references. English-language literature, including abstracts, clinical trials, and review articles, were reviewed. Clinical trials were included if they evaluated hemostatic mouthwashes in patients receiving continued anticoagulation and undergoing dental extractions or various oral surgeries including dental extraction. Eight clinical trials met study selection criteria for evaluation of hemostatic mouthwashes in anticoagulated patients undergoing dental extraction. Eight studies evaluated tranexamic acid; one assessed epsilon aminocaproic acid. All studies were reviewed for efficacy and safety of hemostatic mouthwashes and intensity of continued anticoagulation therapy. Eight small studies enrolled populations that varied in the indications for oral anticoagulation (OA), target INR ranges, and oral surgeries performed. Patients receiving uninterrupted OA and using hemostatic mouthwashes had no greater and, in some cases, lesser bleeding incidence compared with various other treatment groups (including interrupted OA, uninterrupted OA, autologous fibrin glue with uninterrupted OA, and reduced OA with heparin bridge). No severe adverse effects were reported. No studies assessed the risk of thromboembolism between the different treatment strategies. Findings in recent studies indicate that dental extractions in anticoagulated patients can be performed without temporary discontinuation of oral anticoagulant therapy with the use of hemostatic mouthwashes to control localized bleeding. This practice should be more widely adopted due to minimized bleeding and thromboembolic risks.

Identification Of Patients At Low Risk For Recurrent Venous Thromboembolism By Measuring Thrombin Generation

Conclusion: Patients at low risk for recurrent venous thromboembolism (VTE) can be identified by measurement of thrombin generation. Summary: Patients with VTE are often investigated for thrombophilic risk factors. The large number of potential thrombophilic risk factors makes this complex and expensive. The authors sought to determine whether the risk of recurrent VTE could be assessed by a global coagulation assay that measures thrombin generation. This was a prospective cohort study of 914 patients. All patients had a spontaneous VTE and were followed for an average of 47 months after discontinuation of oral anticoagulant therapy. The study period was from July 1992 to July 2005. A commercially available assay was used to measure thrombin generation. Excluded patients included those with secondary VTE, those with recurrent VTE, or those with a known thrombophilic risk factor such as antithrombin, protein C or protein S deficiencies, the presence of lupus anticoagulant, or cancer or pregnancy. The primary outcome measure was an objectively documented episode of recurrent VTE. VTE recurred in 100 patients (11%). There was lower thrombin generation in the patients without recurrent VTE compared with those with recurrent VTE (349.2 ± 108 nN vs 415 ± 110.5 nN, P < .001). In patients with thrombin generation values between 400 nN and 300 nN, the relative risk of recurrence compared to patients with thrombin generations >400 nN was 0.42 (95% confidence interval [CI], 0.26 to 0.67, P < .001). In patients with measured thrombin generations <300 nN relative risk was 0.37 (95% CI, 0.21 to 0.66, P = .001). For 4 years, the probability of VTE recurrence in patients with thrombin generation <400 nN was 6.5% (95% CI, 4.0% to 8.9%). In those patients with thrombin generation values >400, the probability of VTE recurrence was 20.0% (95% CI, 14.9% to 25.1%, P < .001). Patients with thrombin generation <400 nN had a 60% lower recurrence of VTE than those with greater values of thrombin generation (relative risk, 0.40; 95% CI, 0.27 to 0.60; P < .001. Comment: There are data to suggest that patients with idiopathic VTE benefit from longer periods of anticoagulation than those with VTE and a recognizable risk factor such as surgery or trauma. Given the implications of long-term anticoagulant therapy, it is desirable to identify which patients with idiopathic VTE are particularly prone to recurrence. If this study can be confirmed by others, measurement of thrombin generation may prove to be a relatively simple method of stratifying patients for their length of anticoagulation after a first time episode of idiopathic VTE.

Acceptibility of Patient Self-Testing of Oral Anticoagulation in New Patients.

Monitoring oral anticoagulation therapy (OAT) remains a significant burden on health care resources. Patient self-testing (PST) of OAT using point of care devices may alleviate these demands and improve the quality of treatment. Previous studies have shown limited benefit, as recruitment amongst patients previously established on OAT has proven to be difficult with only around 10–15 % of those invited agreeing to participate, suggesting that PST may only be suitable for a minority of patients. We aimed to assess whether PST is more acceptable to patients if offered at the commencement of treatment. 216 consecutive adults referred to anticoagulation clinics were assessed for their suitability for PST. Exclusion criteria included: short therapeutic duration (e.g. pre-cardioversion); known drug/alcohol abuse; atypical INR target values; language barriers; physical/intellectual impairment. Suitable patients were offered the opportunity to perform PST with 2 training sessions and thereafter monitor their INR every 1–2 weeks using CoaguChek S (Roche Diagnostics). It was noted during recruitment of the first 100 patients, that patients awaiting cardioversion accounted for a large proportion of the patients excluded (15/54, 28%), but many patients awaiting cardioversion received OAT in excess of six months. We therefore modified initial entry criteria, to include those with atrial fibrillation awaiting cardioversion. Of the 116 patients subsequently approached 37 (32%) were then recruited to PST (compared with only 17 cardiac patients from the first 100 enrolled into the study). 98 (45%) patients fulfilled our entry criteria for PST, of whom 54 (25%) consented to PST. Of the 118 ineligible patients: 23 had previously received OAT; 15 were awaiting cardioversion; the expected duration of OAT was less than 6 months in 13 patients; and PST was logistically impractical in 32 other patients. A further 35 were excluded for a wide variety of reasons including non-standard INR ranges, language barriers, discontinuation of OAT and planned surgical procedures. Only two of the 54 patients who started PST elected to return to hospital testing. Overall 53 % (52/98) of eligible patients have continued to self-test. The INR values obtained from these patients showed that their oral anticoagulant control remained stable (mean time in therapeutic range of 71%), and compared favourably to those patients electing to attend our routine anticoagulant clinic. Our data show that patients offered PST as an alternative to routine clinic management during induction of anticoagulation were more likely to participate in PST than established patients. Furthermore, the vast majority of patients (96%) continued to self-test, a higher figure than previous studies involving established patients.

Lack of a scientific basis for routine discontinuation of oral anticoagulation therapy before dental treatment

There is a widespread belief among dental practitioners and physicians that oral anticoagulation therapy in which patients receive drugs such as warfarin sodium must be discontinued before dental treatment to prevent serious hemorrhagic complications, especially during and after surgical procedures. The authors examine the scientific basis for properly managing the dosage of anticoagulants for dental patients who are receiving anticoagulation therapy. The authors review the appropriate laboratory test values to which dentists should refer when evaluating for dental treatment patients who are receiving anticoagulation therapy. The authors also review clinical studies, published within the past five years, that focus on the frequency and degree of hemorrhagic and related complications among dental patients who are receiving anticoagulation therapy orally to prevent thromboembolic events. The scientific literature does not support routine discontinuation of oral anticoagulation therapy for dental patients. Use of warfarin sodium as it relates to dental or oral surgical procedures has been well-studied. Some dental studies of antiplatelet therapy are consistent with the findings in warfarin sodium studies. Dental therapy for patients with medical conditions requiring anticoagulation or antiplatelet therapy must provide for potential excess bleeding. Routine discontinuation of these drugs before dental care, however, can place these patients at unnecessary medical risk. The coagulation status--based on the International Normalized Ratio--of patients who are taking these medications must be evaluated before invasive dental procedures are performed. Any changes in anticoagulant therapy must be undertaken in collaboration with the patient's prescribing physician.