Activation of Blood Coagulation after Abrupt or Stepwise Withdrawal of Oral Anticoagulants - A Prospective Study

Complete omission of second-look endoscopy after gastric endoscopic submucosal dissection in real-world practice

Gastric endoscopic submucosal dissection (ESD) is increasingly performed in patients receiving antithrombotic therapy. Second-look endoscopy (SLE) has been performed empirically in several clinical settings. We investigated whether SLE omission was associated with an increased risk of postESD bleeding in all patients, including those administered antithrombotic agents. Between July 2016 and June 2018, 229 patients were treated with a clinical pathway for gastric ESD that involved SLE on the day after ESD (SLE group). Between September 2018 and May 2020, 215 patients were treated using a clinical pathway that did not include SLE (nonSLE group). We retrospectively compared the incidence of postESD bleeding among the propensity score-matched cohorts and determined the risk factors for postESD bleeding using multivariate analysis. The propensity score-matched cohorts showed no significant differences in the incidence of postESD bleeding between the SLE (3.2%) and nonSLE (5.1%) groups. Multivariate analysis revealed that the presence of lesions in the lower gastric body (adjusted odds ratio [OR] 2.17, 95% confidence interval [CI] 1.06-4.35, P.03) was a significant risk factor for postESD bleeding during admission, whereas resected specimen size ≥ 40 mm (adjusted OR 3.21, 95% CI 1.19-8.19, P.02) and antiplatelet therapy (adjusted OR 4.16, 95% CI 1.47-11.80, P.007) were significant risk factors after discharge. Complete omission of SLE after gastric ESD does not increase postESD bleeding in clinical practice.

Rosuvastatin treatment decreases plasma procoagulant phospholipid activity after a VTE: A randomized controlled trial

BACKGROUND

Venous thromboembolism (VTE) is a frequent cardiovascular disease with severe complications, including recurrence and death. There is a great need for alternative prophylactic treatment options as anticoagulation is accompanied by increased bleeding risk. Statins are reported to reduce the risk of incident and recurrent VTE, but the mechanisms are elusive. Procoagulant phospholipids (PPL), and phosphatidylserine in particular, are crucial for efficient coagulation activation, but no studies have investigated the effect of statin treatment on plasma PPL activity.

OBJECTIVES

To investigate the impact of rosuvastatin treatment on plasma PPL activity and levels of extracellular vesicles (EVs).

PATIENTS/METHODS

Patients with a history of VTE (≥18 years) allowed to stop anticoagulant treatment were randomized to either 20 mg/day of rosuvastatin treatment or no treatment for 28 days in the Statins Reduce Thrombophilia (NCT01613794) trial. Plasma samples were collected at baseline and study end. PPL activity was measured in samples from 245 participants using a factor Xa-dependent clotting assay and EV levels by flow cytometry.

RESULTS

Rosuvastatin treatment yielded an overall 22% (95% confidence interval [CI] -38.2 to -5.8) reduction in PPL activity, and 37% (95% CI -62.9 to -11.2) reduction in PPL activity in participants with a history of pulmonary embolism. The effect of rosuvastatin on plasma PPL activity was not explained by changes in total cholesterol nor change in levels of total- or platelet-derived EVs.

CONCLUSIONS

Rosuvastatin treatment caused a substantial decrease in plasma PPL activity, suggesting that a PPL-dependent attenuation of coagulation activation may contribute to a reduced VTE risk following statin treatment.

The incidence of cardiovascular thrombotic complications after laparoscopic resection in colorectal cancer in Japanese hospitals: A large‐scale clinical study

Aim

The aim of this retrospective study was to investigate the incidence of cardiovascular thrombotic complications after laparoscopic resection in colorectal cancer.

Methods

This study involved 2017 patients with stages 0‐III colorectal cancer who underwent laparoscopic surgery at 17 Japanese hospitals between January 2010 and December 2013. We assessed the incidence of postoperative cardiovascular thrombotic and haemorrhagic complications.

Results

Laparoscopic surgeries were performed in 1152 men and 865 women with 1405 colon and 612 rectal cancers, respectively. Overall, 3%, 38%, 17%, 8%, and 9% of patients had comorbidities of heart failure, high blood pressure, diabetes, history of stroke, and vascular disease, respectively. Antithrombotic agents were being consumed by 17% of patients. The types (and perioperative rest periods) of the antithrombotic agents were aspirin in 58% (18.6 days), clopidogrel in 19% (21.1 days), cilostazol in 13% (13.3 days), and warfarin potassium in 21% (14.6 days) of cases with antithrombotic agents. Surgical time and blood loss in the total cohort were 234 minutes and 56 mL. Four cases (0.2%) had cardiovascular thrombotic complications, including one severe cardiac infarction and one stroke with major sequelae (CHADS2 scores were 2 points in both cases). Hemorrhagic complications occurred in 19 cases (0.9%). In particular, the incidence of the major gastroduodenal haemorrhagic ulcer was higher in cases with antithrombotic agents than without them (0.05% vs 0%, P = .02).

Conclusion

The incidence of cardiovascular thrombotic complications was rare, although severe cardiac infarction and stroke could occur even after minimally invasive surgery in colorectal cancer.

Current evidence and issues of endoscopic submucosal dissection for gastric neoplasms during antithrombotic therapy

Endoscopic submucosal dissection (ESD) for gastric neoplasms is a useful treatment globally. However, postoperative bleeding after gastric ESD is a serious, and sometimes life-threatening complication in patients receiving antithrombotic drugs, because antithrombotic drugs are considered to increase the risk of postoperative bleeding after gastric ESD. In contrast, withdrawal of antithrombotic drugs during the perioperative period increases the risk of thrombotic complications. Guidelines for the management of antithrombotic drugs during the periendoscopic period have been published by different countries, and recent guidelines place greater emphasis on the risk of thromboembolism with the discontinuation of antithrombotic drugs than on the risk of bleeding with the continuation of antithrombotic drugs. Several studies have reported on the validity of these guidelines, and clinical evidence is being established. Most studies reported that gastric ESD under continuation of aspirin or cilostazol did not increase the risk of bleeding, whereas heparin replacement was strongly associated with a higher risk of bleeding. However, the data regarding some clinical issues about the management of antithrombotic drugs, such as the safety of gastric ESD under continuation of thienopyridine, administration of multiple antithrombotic drugs including dual antiplatelet and anticoagulants (warfarin and direct oral anticoagulant), and effective prophylactic methods for postoperative bleeding after gastric ESD are lacking. Larger clinical data are needed to resolve the remaining issues in the future.

Rosuvastatin use improves measures of coagulation in patients with venous thrombosis

Aims

Observational studies indicate that statins reduce the risk of recurrent venous thrombosis (VT). However, trials have not been performed and the mechanism is unknown. We aimed to determine whether statin therapy improves the coagulation profile in patients with prior VT.

Methods and results

Randomized clinical trial (NCT01613794). Patients were randomized to rosuvastatin 20 mg/day for 4 weeks or no intervention. Blood was drawn at baseline and at end of study. The primary outcome was factor (F) VIII:C. In total, five coagulation factors were measured: FVIII:C, von Willebrand factor:Ag, FVII:C, FXI:C, and D-dimer. Among 247 randomized participants, mean age was 58 years, 62% were women and 49% had unprovoked VT. For all tested coagulation factors, mean levels were clearly decreased at end of study in rosuvastatin users, whereas they hardly differed in non-statin users. Results were most consistent for FVIII:C where mean FVIII:C levels were 7.2 IU/dL [95% CI (confidence interval) 2.9-11.5] lower in rosuvastatin users, while among non-users, no change in FVIII:C was observed (mean difference -0.1; 95% CI -3.0 to 2.9). The mean age and sex adjusted difference in FVIII:C change was -6.7 IU/dL (95% CI -12.0 to -1.4) in rosuvastatin users vs. non-users. Subgroup analyses revealed that the decrease in coagulation factors by rosuvastatin was more pronounced in participants with unprovoked VT and in those with cardiovascular risk factors.

Conclusion

Rosuvastatin 20 mg/day substantially improved the coagulation profile among patients with prior VT. These results suggest that statin therapy might be beneficial in patients at risk of recurrent VT.

Safety of Cold Snare Polypectomy in Patients Receiving Treatment with Antithrombotic Agents

BACKGROUND

With the aging of the population and rising incidence of thromboembolic events, the clinical use of antithrombotic agents is also increasing. There are few reports yet on the management of antithrombotic agent use in patients undergoing cold snare polypectomy (CSP).

AIMS

The aim of this study was to evaluate whether continued administration of antithrombotic agents in patients undergoing CSP would be associated with an increased rate of delayed post-polypectomy bleeding (DPPB).

METHODS

A total of 1177 colorectal polyps in 501 patients were resected at Omori Red Cross Hospital between October 2017 and March 2018. The polyps were divided into two groups depending on whether the patients received antithrombotic agent treatment or not: the antithrombotic group (911 polyps) and the no-antithrombotic group (266 polyps).

RESULTS

Among the 1177 polyp resections, there was no case of DPPB, including in the antithrombotic group. Immediate bleeding occurred in a total of 63 (5.4%) cases. Polyp location in the rectum (OR (95% CI) 2.64 (1.223-5.679); p = 0.013), polyp size ≥ 6 mm (OR (95% CI) 4.64 (2.719-7.933); p < 0.001), polypoid growth pattern (OR (95% CI) 2.78 (1.607-4.793); p < 0.001), and antithrombotic agent use (OR (95% CI) 2.98 (1.715-5.183); p < 0.001) were identified as significant risk factors of immediate bleeding.

CONCLUSIONS

Continued use of antithrombotic agents does not increase the risk of DPPB, even in those receiving multiple antithrombotic agents. Thus, it is safe to perform CSP even in multiple agent users. Prospective, randomized studies are necessary to confirm our results.

Risk prediction of recurrent venous thrombosis; where are we now and what can we add?

BACKGROUND

Several models are available to predict recurrent venous thrombosis (VT) in patients with unprovoked first events.

OBJECTIVES

To validate these prediction models externally.

METHODS

Within the MEGA follow-up study (n = 3750), we externally validated the Vienna and DASH score. These models were validated (a) by using the original study's criteria for patients with unprovoked VT and (b) by using our own criteria for unprovoked VT. In addition, absolute recurrence risks based on individual VT risk factors were calculated.

RESULTS

The recurrence rate was 5.2 (95% CI, 4.6-5.9) per 100 patient-years in those who had a first unprovoked VT according to our definition. For the Vienna model it was 3.4 per 100 patient-years and for DASH 3.8 per 100 patient-years. The C-statistic was 0.62 for Vienna and 0.65 for DASH. The C-statistic declined to 0.58 for both Vienna and DASH when we used our own definition of "unprovoked VT." Within the provoked group a strong gradient in risk was found dependent on the presence of traditional risk factors or biomarkers in a patient.

CONCLUSIONS

The ability to distinguish patients' recurrence risks is lower than proposed in the original prediction model studies and dependent on the definition that is used for an unprovoked first event. Furthermore, our results suggest that a more-refined risk estimation is possible, also in patients with a provoked first event, who are currently all classified as low risk.

Rosuvastatin use reduces thrombin generation potential in patients with venous thromboembolism: a randomized controlled trial

Essentials The role of statins in hemostasis and venous thromboembolism (VTE) prophylaxis is not clear. This trial assessed whether rosuvastatin use affects thrombin generation in patients with VTE. Endogenous thrombin potential and peak were decreased by 10% and 5% with rosuvastatin therapy. These results provide basis for trials on the efficacy of statins in reducing recurrent VTE risk. SUMMARY: Background Statin therapy could form an alternative prophylactic treatment for venous thromboembolism (VTE) if statins are proven to downregulate hemostasis and prevent recurrent VTE, without increasing bleeding risk. Objectives The STAtins Reduce Thrombophilia (START) trial investigated whether statin affects coagulation in patients with prior VTE. Patients/methods After anticoagulation withdrawal, patients were randomized to rosuvastatin 20 mg day-1 for 4 weeks or no intervention. Plasma samples taken at baseline and at the end of the study were analyzed employing thrombin generation assay. Results and conclusions The study comprised 126 rosuvastatin users and 119 non-users. Mean age was 58 years, 61% were men, 49% had unprovoked VTE and 75% had cardiovascular (CV) risk factors. Endogenous thrombin potential (ETP) increased from baseline to end of study in non-statin users (mean 97.22 nm*min; 95% CI, 40.92-153.53) and decreased in rosuvastatin users (mean -24.94 nm*min; 95% CI, -71.81 to 21.93). The mean difference in ETP change between treatments was -120.24 nm*min (95% CI, -192.97 to -47.51), yielding a 10.4% ETP reduction by rosuvastatin. The thrombin peak increased in both non-statin (mean 20.69 nm; 95% CI, 9.80-31.58) and rosuvastatin users (mean 8.41 nm; 95% CI -0.86 to 17.69). The mean difference in peak change between treatments was -11.88 nm (95% CI, -26.11 to 2.35), yielding a 5% peak reduction by rosuvastatin. Other thrombin generation parameters did not change substantially. The reduction in ETP and peak by rosuvastatin was more pronounced in the subgroups of participants with CV risk factors and with unprovoked VTE. We conclude that rosuvastatin reduces thrombin generation potential in patients who had VTE.

A pilot study documenting increased thrombin generation following abrupt withdrawal of heparin therapy in healthy dogs

OBJECTIVE

To document if a transient hypercoagulable state occurs in healthy dogs following abrupt cessation of unfractionated heparin (UFH) therapy.

DESIGN

Prospective experimental pilot study.

SETTING

University research facility.

ANIMALS

Seven adult random-source male dogs.

INTERVENTION

Thromboelastography (TEG) and thrombin-antithrombin (TAT) complex formation were used to assess coagulation status in healthy dogs. Seven adult research dogs received 200-300 IU/kg subcutaneous UFH every 8 hours for 4 days. A final IV bolus of 100 IU/kg was given on day 4 and the peak measured heparin concentration 1 hour later is defined as the start of heparin withdrawal (time 0). Citrated whole blood samples were collected at baseline (prior to heparin administration) and 3, 6, 12, 30, and 48 hours after UFH withdrawal. At all time points, a kaolin-activated TEG was performed and citrated plasma for measurement of TAT concentration was collected for batch analysis. Fibrinogen concentration, PCV, total plasma proteins, and platelet count were measured at baseline and 48 hours after heparin withdrawal.

MEASUREMENTS AND MAIN RESULTS

Compared to baseline, TAT was increased 12 hours after heparin withdrawal and returned to baseline by 30 hours. TEG clot formation time (K) was decreased 30 and 48 hours after heparin withdrawal.

CONCLUSION

TAT results suggest that a transient increase in thrombin generation developed 12 hours after withdrawal of UFH therapy. Though clot kinetics were rapid compared to baseline beginning 30 hours after heparin withdrawal, a return to baseline was not documented. Future studies are warranted to determine the clinical relevance of these results and to evaluate the effect of UFH withdrawal in critically ill animals.

Efficacy of polyglycolic acid sheets and fibrin glue for prevention of bleeding after gastric endoscopic submucosal dissection in patients under continued antithrombotic agents

BACKGROUND

A novel method for the prevention of bleeding after gastric endoscopic submucosal dissection (ESD) is necessary, as the numbers of patients taking antithrombotic agents have increased. This study aimed to assess the efficacy and safety of the covering method using polyglycolic acid (PGA) sheets and fibrin glue for ESD-induced ulcer in preventing post-ESD bleeding in patients under continued antithrombotic agents.

METHODS

One hundred five consecutive gastric tumors among 84 patients who were treated by ESD under continued antithrombotic agents between April 2014 and September 2015 were enrolled in this study. The patients were classified into two groups, the covering group (52 lesions among 38 patients; those with ESD in whom PGA sheets and fibrin glue were used as the covering method) and the control group (53 lesions among 46 patients; ESD only), and their post-ESD bleeding rates were compared.

RESULTS

No significant differences were seen in the number and type of antithrombotic agents, lesion location, median procedure time, and median resected specimen size between the groups. ESD was completed in all cases, with no cases of uncontrollable bleeding during the procedure. Post-ESD bleeding occurred in 5.8% (3/52) and 20.8% (11/53) in the covering and control groups, respectively. The post-ESD bleeding rate significantly differed between the groups (P = 0.04; odds ratio, 0.23; 95% confidential interval, 0.06-0.89). No adverse events were associated with the use of PGA sheets and fibrin glue.

CONCLUSIONS

The covering method using PGA sheets and fibrin glue has the potential to reduce post-ESD bleeding in patients receiving continued antithrombotic agents.

Anticoagulation in venous Thrombosis

Major studies addressing various aspects of the treatment of deep vein thrombosis are reviewed. It has lately been demonstrated that heparin should be dosed according to body weight and is preferably given as subcutaneous injections twice daily. Alternatively, low-molecular-weight heparins may be given in a fixed dose once daily, which does not require monitoring. Oral anticoagulation should be started concomitantly with heparin and targeted at an international normalized ratio of 2.0-3.0. This treatment should continue for a longer duration than previously accepted, in many cases for 6 months. For patients with contraindications to oral anticoagulation, secondary prophylaxis with a low-molecular-weight heparin is also effective and safe.

Clinical events after interruption of anticoagulation in patients with atrial fibrillation: An analysis from the ENGAGE AF-TIMI 48 trial

BACKGROUND

Patients with atrial fibrillation (AF) who interrupt anticoagulation are at high risk of thromboembolism and death.

METHODS AND RESULTS

Patients enrolled in the ENGAGE AF-TIMI 48 trial (randomized comparison of edoxaban vs. warfarin) who interrupted study anticoagulant for >3 days were identified. Clinical events (ischemic stroke/systemic embolism, major cardiac and cerebrovascular events [MACCE]) were analyzed from day 4 after interruption until day 34 or study drug resumption. During 2.8 years median follow-up, 13,311 (63%) patients interrupted study drug for >3 days. After excluding those who received open-label anticoagulation during the at-risk window, the population for analysis included 9148 patients. The rates of ischemic stroke/systemic embolism and MACCE post interruption were substantially greater than in patients who never interrupted (15.42 vs. 0.26 and 60.82 vs. 0.36 per 100 patient-years, respectively, p_adj < .001). Patients who interrupted study drug for an adverse event (44.1% of the cohort), compared to those who interrupted for other reasons, had an increased risk of MACCE (HR_adj 2.75; 95% CI 2.02-3.74, p < .0001), but similar rates of ischemic stroke/systemic embolism. Rates of clinical events after interruption of warfarin and edoxaban were similar.

CONCLUSION

Interruption of study drug was frequent in patients with AF and was associated with a substantial risk of major cardiac and cerebrovascular events over the ensuing 30 days. This risk was particularly high in patients who interrupted as a result of an adverse event; these patients deserve close monitoring and resumption of anticoagulation as soon as it is safe to do so.

Bleeding Risk Related to Upper Gastrointestinal Endoscopic Biopsy in Patients Receiving Antithrombotic Therapy: A Multicenter Prospective Observational Study

BACKGROUND

Although antithrombotic agents are widely used for cardiac and cerebrovascular disease prevention, they increase the risk of gastrointestinal (GI) bleeding.

OBJECTIVE

To examine GI bleeding risk in association with an esophagogastroduodenoscopy (EGD) biopsy performed in patients without cessation of antithrombotic therapy.

METHODS

This study was prospectively conducted at 14 centers. EGD biopsies were performed in patients receiving antithrombotic agents without cessation, as well as age- and sex-matched controls not receiving antithrombotic therapy. Patients treated with warfarin before the biopsy had a prothrombin time-international normalized ratio level <3.0. The proportion of GI bleeding events was compared between the groups.

RESULTS

The patient group (n = 277) underwent a total of 560 biopsies while continuing antithrombotic therapy, of whom 24 were receiving multiple antiplatelet drugs, and 9 were receiving both antiplatelet and anticoagulant agents. The control patients (n = 263) underwent 557 biopsies. The upper-GI bleeding rate within 30 days after the EGD biopsy did not increase in patients without cessation of antithrombotic treatment, regardless of receiving single or multiple antithrombotic agents.

CONCLUSIONS

We found no significant increase in upper-GI bleeding risk following an EGD biopsy in patients taking antithrombotic agents, suggesting its safety without the need for antithrombotic treatment interruption.

A Korean Multi-Center Survey about Warfarin Management before Gastroenterological Endoscopy in Patients with a History of Mechanical Valve Replacement Surgery

Background

Guidelines for esophagogastroduodenoscopy (EGD) in the West allow the continued use of warfarin under therapeutic international normalized ratio (INR) level. In Korea, no guidelines have been issued regarding warfarin treatment before EGD. The authors surveyed Korean cardiac surgeons about how Korean cardiac surgeons handle warfarin therapy before EGD using a questionnaire. Participants were requested to make decisions regarding the continuation of warfarin therapy in two hypothetical cases.

Methods

The questionnaire was administered to cardiac surgeons and consisted of eight questions, including two case scenarios.

Results

Thirty-six cardiac surgeons at 28 hospitals participated in the survey, and 52.7% of the participants chose to stop warfarin before EGD in aortic valve replacement patients without risk factors for thromboembolism. When the patient’s INR level was 2, 31% of the participants indicated that they would choose to continue warfarin therapy. For EGD with biopsy, 72.2% of the participants chose warfarin withdrawal, and 25% of the participants chose heparin replacement. In mitral valve replacement patients, 47.2% of the participants chose to discontinue warfarin, and 22.2% of the participants chose heparin replacement. For EGD with biopsy in patients with a mitral valve replacement, 58.3% of the participants chose to stop warfarin, and 41.7% of the participants chose heparin replacement.

Conclusion

This study demonstrated that attitudes regarding warfarin treatment for EGD are very different among Korean surgeons. Guidelines specific to the Korean population are required.

Quality assurance manual of endoscopic screening for gastric cancer in Japanese communities

The Japanese government introduced endoscopic screening for gastric cancer in 2015 as a public policy based on the Japanese guidelines on gastric cancer screening. To provide appropriate endoscopic screening for gastric cancer in Japanese communities, we developed a quality assurance manual of endoscopic screening and recommend 10 strategies with their brief descriptions as follows: (i) Formulation of a committee responsible for implementing and managing endoscopic screening, and for deciding the suitable implementation methods in consideration of the local context; (ii) Development of an interpretation system that leads to a final judgement to standardize endoscopic examination and improve its accuracy; (iii) Preparation of management and reporting systems for adverse effects by the committee for safety management; (iv) Obtaining informed consent before operation following adequate explanations regarding the benefits and harms of endoscopic screening; (v) Avoidance of frequent screenings to reduce false-positive results and overdiagnosis. As a reference, the target age group is ≥50 years, and the screening interval is 2 years; (vi) Keeping the biopsy rate within 10% as post-biopsy bleeding may occur. Before endoscopic screening, any history of antithrombotic drug usage should be checked; (vii) Nonadministration of sedation in endoscopic screening for safety management; (viii) Adherence to proper endoscopic cleaning and disinfection to reduce infection; (ix) Use of a checklist to achieve optimal program preparation when municipal governments introduce endoscopic screening; (x) Identification of the aims and roles by referring to a checklist if primary care physicians decide to participate in endoscopic screening.

Risk of recurrent venous thromboembolism after discontinuation of vitamin K antagonist treatment: a nested case-control study

Essentials Vitamin K antagonists (VKA) in venous thromboembolism (VTE) lower the risk of recurrences. 41 841 VKA-treated VTE patients had 1242 recurrent VTEs on therapy or early after cessation. An increased risk of recurrence was found in the first 120 days after VKA cessation. Patient education for the early detection of recurrent VTE after VKA cessation is recommended.

SUMMARY

Background The standard treatment for venous thromboembolism (VTE) and the prevention of recurrent VTE (rVTE) consists of anticoagulant therapy. The optimal duration of anticoagulation depends on the presence of risk factors for rVTE. Objectives To estimate the risk of rVTE in association with time since discontinuation of vitamin K antagonist (VKA) treatment. Methods From the UK Clinical Practice Research Datalink with linked information on hospitalization and cause of death, a cohort of patients with a first VTE receiving initial VKA treatment between 2001 and 2013 was formed. With a nested case-control approach, patients with incident rVTE (cases) were matched to patients with VTE but without rVTE (controls). Adjusted rate ratios (RRs) of rVTE associated with time since VKA discontinuation relative to current VKA use were estimated from conditional logistic regression. Results The VTE cohort comprised 41 841 patients with 1242 rVTEs and 6205 matched controls. The RR of rVTE was increased within 60 days following VKA discontinuation (RR 2.23, 95% confidence interval [CI] 1.71-2.91) and within 61-120 days following VKA discontinuation (RR 1.49, 95% CI 1.08-2.05) relative to current VKA use. The increased RR corresponded to excess incidence rates of 6.72 (95% CI 3.90-10.06) rVTE cases per 100 person-years within 60 days, and of 2.68 (95% CI 0.42-5.58) rVTE cases per 100 person-years within 61-120 days after VKA discontinuation. Conclusions VKA discontinuation results in a transient increased risk of rVTE, which peaks within 60 days and lasts for up to 120 days after VKA discontinuation. Specific patient education for increased vigilance for signs and symptoms of recurrences is recommended in this period.

Effect of Adherence to Oral Anticoagulants on Risk of Stroke and Major Bleeding Among Patients With Atrial Fibrillation

BACKGROUND

In comparison to warfarin, non-vitamin K antagonist oral anticoagulants (NOACs) have the advantages of ease of dosing, fewer drug interactions, and lack of need for ongoing monitoring. We sought to evaluate whether these advantages translate to improved adherence and whether adherence is associated with improved outcomes in patients with atrial fibrillation.

METHODS AND RESULTS

We performed a retrospective cohort analysis by using a large US commercial insurance database to identify 64 661 patients with atrial fibrillation who initiated warfarin, dabigatran, rivaroxaban, or apixaban treatment between November 1, 2010, and December 31, 2014. During a median of 1.1 y of follow-up, 47.5% of NOAC patients had a proportion of days covered of ≥80%, compared with 40.2% in warfarin patients (P<0.001). Patients with CHA2DS2-VASc (risk based on the presence of congestive heart failure, hypertension age 65-74 y, age ≥75 y, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category) score ≥4 were at increased risk of stroke when they were not taking anticoagulation ≥1 month versus <1 week (1-3 months: hazard ratio [HR] 1.96, 3-6 months: HR 2.64, ≥6 months: HR 3.66; all P<0.001). Patients with CHA2DS2-VASc score 2 or 3 were at increased risk of stroke when they were not taking anticoagulation ≥6 months (HR 2.73, P<0.001). In these patients with CHA2DS2-VASc score ≥2, nonadherence was not associated with intracranial hemorrhage. Among patients with CHA2DS2-VASc score 0 or 1, time not taking anticoagulation was not associated with stroke, but not taking anticoagulation ≥3 months was associated with a significant reduction of bleeding.

CONCLUSIONS

Adherence to anticoagulation is poor in practice and may be modestly improved with NOACs. Adherence to therapy appears to be most important in patients with CHA2DS2-VASc score ≥2, whereas the benefits of anticoagulation may not outweigh the harms in patients with CHA2DS2-VASc score 0 or 1.

Perioperative complications of endoscopic submucosal dissection for early gastric cancer in elderly Japanese patients 75 years of age or older

OBJECTIVE

The number of endoscopic submucosal dissection (ESD) procedures for early gastric cancers among patients 75 years of age or older has been increasing. We herein examined both the outcomes and complications of ESD in elderly patients.

METHODS

We investigated the effects of underlying diseases, lesion characteristics, treatment outcomes and complications during and in the postoperative periods of ESD among elderly patients 75 years of age or older versus non-elderly patients less than 75 years of age. Patients A total of 318 early gastric cancers in consecutive 307 patients, all of whom underwent ESD for gastric cancer, were included in this study.

RESULTS

The number of patients with hypertension and ischemic heart disease was significantly higher in the elderly group than in the non-elderly group. The proportion of lesions with an absolute indication, extended indication or no indication was not significantly different between the groups. During the ESD procedure, the use of atropine sulfate for bradycardia was significantly more frequent in the elderly group. No significant differences were observed between the groups in terms of the treatment for hypertension, oxygen administration or incidence of perforation. In addition, there were no significant differences with respect to oxygen administration, postoperative bleeding or the occurrence of fever and/or pneumonia after the ESD procedure.

CONCLUSION

Although bradycardia was more frequently observed in the elderly patients during ESD in this study, ESD was performed safely and managed appropriately, with infrequent postoperative complications. ESD appears to be effective, even in elderly patients.

Guidelines for gastroenterological endoscopy in patients undergoing antithrombotic treatment

Guidelines for gastroenterological endoscopy in patients undergoing antithrombotic treatment have been produced by the Japan Gastroenterological Endoscopy Society in collaboration with the Japan Circulation Society, the Japanese Society of Neurology, the Japan Stroke Society, the Japanese Society on Thrombosis and Hemostasis and the Japan Diabetes Society. Previous guidelines from the Japan Gastroenterological Endoscopy Society have focused primarily on prevention of hemorrhage after gastroenterological endoscopy as a result of continuation ofantithrombotic therapy, without considering the associated risk of thrombosis. The new edition of the guidelines includes discussions of gastroenterological hemorrhage associated with continuation of antithrombotic therapy, as well as thromboembolism associated with withdrawal of antithrombotic therapy.

Inpatient pulmonary embolism after elective primary total hip and knee arthroplasty in the United States

BACKGROUND

The incidence of inpatient pulmonary embolism in patients who have elective primary hip and knee arthroplasty in the United States is unknown. Prior studies have included patients with cancer, trauma, or revisions. The goal of this study was to determine the incidence and risks of inpatient pulmonary embolism after elective arthroplasty by type of procedure.

METHODS

We used the 1998 to 2009 Healthcare Cost and Utilization Project Nationwide Inpatient Sample for this retrospective cohort study. Patients who were sixty years of age or older and underwent elective primary total hip or knee arthroplasty were included. The study variable was the type of arthroplasty: total hip, total knee, or two joints. Inpatient pulmonary embolism was the primary outcome; mortality was secondary. Logistic regression determined the adjusted odds ratios of inpatient pulmonary embolism by procedure, adjusting for age, sex, Charlson Comorbidity Index, atrial fibrillation, and surgical indication.

RESULTS

Records represented 5,044,403 hospital discharges after primary total hip or knee arthroplasty. Total knee arthroplasty comprised 66% of the admissions. Less than 5% of patients had two joint procedures. The overall incidence of pulmonary embolism was 0.358% (95% confidence interval [CI], 0.338, 0.378). The incidence of pulmonary embolism differed by procedure and was highest among patients who had two-joint arthroplasty (0.777%; 95% CI, 0.677, 0.876), was lowest in recipients of total hip arthroplasty (0.201%; 95% CI, 0.179, 0.223), and was intermediate in patients who had total knee arthroplasty (0.400%; 95% CI, 0.377, 0.423). The adjusted odds ratios of pulmonary embolism in patients who had two joint procedures were 3.89 times higher than among patients who had total hip arthroplasty, controlling for other factors.

CONCLUSIONS

Elective total knee arthroplasty is associated with a higher incidence and odds of inpatient pulmonary embolism than is total hip arthroplasty; multiple procedures pose the highest risk for pulmonary embolism and associated mortality.

Postoperative bleeding risk for cutaneous surgery in the head and neck region with continued phenprocoumon therapy

In a total of 171 surgical procedures for lesions in the head and neck region in patients in whom phenprocoumon therapy was not stopped, 16 (9%) postoperative bleeding events were observed over a follow-up period of two weeks. Local measures were sufficient in all cases except one severe case where blood transfusion was needed and anticoagulant treatment was stopped for 7 days. The bleeding risk was significantly higher for the surgical procedures of the nose than those in other areas (21% versus 6%, P = 0.014), but was not influenced by the international normalized ratio (INR) of blood coagulation, size, site and type of the lesion, surgical procedure, and sex and age of the patients. The bleeding rate in patients not on any anticoagulation therapy was significantly lower (6/211 = 3%). Across both groups, just over 80% of the bleeding episodes were within the first two days (55% on the same day and 32% on the next day) of the surgery. No bleeding was recorded after 5 days. Our data suggest that cutaneous surgery in the head and neck region can be safely performed with continued phenprocoumon therapy in most cases in an INR range of 1.3-3.4, but rarely severe bleeding does occur and can be managed with a close-contact follow-up and with 24-h on call services during the first two days postoperatively.

Evaluation of the acute coronary syndrome safety profile of dabigatran etexilate in patients undergoing major orthopedic surgery: findings from four Phase 3 trials

INTRODUCTION

Several anticoagulants have been associated with a 'rebound effect' that potentially increases the risk of thrombosis and cardiovascular events following discontinuation. Four Phase 3 trials of dabigatran etexilate in major orthopedic surgery incorporated measures to assess the risk of acute coronary syndrome (ACS) events during and after treatment.

MATERIALS AND METHODS

Patients in RE-MOBILIZE®, RE-MODEL™, RE-NOVATE®, and RENOVATE® II were randomized to dabigatran etexilate (150 mg or 220mg once daily) or enoxaparin for 6-35 days, and followed for up to 90 days. ACS data were tabulated from investigator-reported serious adverse events using ACS-specific Medical Dictionary for Regulatory Authorities (MedDRA) lower-level terms. To ensure that all ACS events were identified in the initial three studies, RE-MOBILIZE®, RE-MODEL™, and RE-NOVATE®, a broader list of MedDRA terms was prespecified that would trigger treatment-blinded adjudication.

RESULTS

When pooling the four trials, patients receiving dabigatran etexilate 220 mg had the fewest treatment-emergent, investigator-reported ACS events (6 [0.16%] vs 14 [0.51%] for dabigatran 150 mg and 13 [0.35%] for enoxaparin). Corresponding post-treatment rates were 2 (0.06%), 1 (0.04%), and 4 (0.11%). Similarly, treatment-emergent centrally adjudicated definite or likely ACS events in the first three trials were fewer in patients on dabigatran 220 mg (16 [0.60%]) than dabigatran 150 mg (26 [0.95%]) and enoxaparin (20 [0.74%]). The corresponding numbers post treatment were 2, 2, and 7. None of these between-group differences were statistically significant.

CONCLUSION

No increased ACS signal was detected with dabigatran etexilate compared with enoxaparin during or after treatment.

Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

High-quality anticoagulation management is required to keep these narrow therapeutic index medications as effective and safe as possible. This article focuses on the common important management questions for which, at a minimum, low-quality published evidence is available to guide best practices.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

Most practical clinical questions regarding the management of anticoagulation, both oral and parenteral, have not been adequately addressed by randomized trials. We found sufficient evidence for summaries of recommendations for 23 questions, of which only two are strong rather than weak recommendations. Strong recommendations include targeting an international normalized ratio of 2.0 to 3.0 for patients on vitamin K antagonist therapy (Grade 1B) and not routinely using pharmacogenetic testing for guiding doses of vitamin K antagonist (Grade 1B). Weak recommendations deal with such issues as loading doses, initiation overlap, monitoring frequency, vitamin K supplementation, patient self-management, weight and renal function adjustment of doses, dosing decision support, drug interactions to avoid, and prevention and management of bleeding complications. We also address anticoagulation management services and intensive patient education.

CONCLUSIONS

We offer guidance for many common anticoagulation-related management problems. Most anticoagulation management questions have not been adequately studied.

The management of anticoagulants perioperatively

Perioperative management of anticoagulants requires one to balance the patient's risk factors for operative bleeding, the type of operation to be performed, and the patient's risk of thromboembolism. At present, no set algorithm exists for the perioperative management of all the anticoagulants. In this article, we address the perioperative management of the most commonly used anticoagulants seen in practice today, such as warfarin, heparin, dabigatran, clopidogrel, and aspirin, for the most commonly performed general thoracic operations.

Bleeding incidence after oral surgery with continued oral anticoagulation

OBJECTIVES

The aim of this retrospective study was to assess the incidence of postoperative hemorrhage in patients treated with coumarins without interruption of the anticoagulant treatment undergoing oral surgical procedures, mostly osteotomies for tooth removal, when compared with patients who had never been anticoagulated.

MATERIAL AND METHODS

Six hundred thirty-seven patients underwent 934 oral surgical procedures on an outpatient basis. The INR was measured preoperatively being 2.44 in the mean SD 0.61. Local hemostasis was carried out routinely (80%) with collagen fleece, local flap, and acrylic splint.

RESULTS

Of these 637 patients, 47 presented with a postoperative hemorrhage (7.4%), 15 of these 47 cases had to be treated in hospital (2.4%). All patients showed up finally with a good wound healing, no administration of blood was necessary, and local measures revealed to be sufficient in all cases except for two patients, where the preoperative anticoagulant treatment had to be changed for 6 days. The bleeding incidence in 285 patients with comparable oral surgical procedures, who had never been anticoagulated, was 0.7%.

CONCLUSIONS

The results suggest that oral surgical procedures can be performed safely without alteration of the oral anticoagulant treatment. CINICAL RELEVANCE: Local hemostasis with collagen fleece, local flap, and acrylic splint seems to be sufficient to prevent postoperative bleeding.

Peri-operative management of ophthalmic patients taking antithrombotic therapy

Increasing number of patients presenting for ophthalmic surgery are using oral anti-coagulant and anti-platelet therapy. The current practice of discontinuing these drugs preoperatively because of a presumed increased risk of bleeding may not be evidence-based and could pose a significant risk to the patient's health. To provide an evidence-based review on the peri-operative management of ophthalmic patients who are taking anti-thrombotic therapy. In addition, we briefly discuss the underlying conditions that necessitate the use of these drugs as well as management of the operative field in anti-coagulated patients. A semi-systematic review of literature was performed. The databases searched included MEDLINE, EMBASE, database of abstracts of reviews of effects (DARE), Cochrane controlled trial register and Cochrane systematic reviews. In addition, the bibliographies of the included papers were also scanned for evidence. The published data suggests that aspirin did not appear to increase the risk of serious postoperative bleeding in any type of ophthalmic surgery. Topical, sub-tenon, peri-bulbar and retrobulbar anaesthesia appear to be safe in patients on anti-thrombotic (warfarin and aspirin) therapy. Warfarin does not increase the risk of significant bleeding in most types of ophthalmic surgery when the INR was within the therapeutic range. Current evidence supports the continued use of aspirin and with some exceptions, warfarin in the peri-operative period. The risk of thrombosis-related complications on disruption of anticoagulation may be higher than the risk of significant bleeding by continuing its use for most types of ophthalmic surgery.

Perioperative management of anticoagulation: guidelines translated for the clinician

The perioperative management of patients taking vitamin K antagonists (VKAs) is an evolving area of medicine and poses significant challenges for health care providers. It has been estimated that this issue affects approximately 250,000 patients annually, and the number of patients requiring chronic anticoagulation continues to increase. The lack of evidence, along with the wide variety of clinical scenarios, requires complex decision making on the part of clinicians. In general, when a patient on chronic anticoagulation requires a planned procedure, the clinician must assess the risk of perioperative thrombotic events and the risk of perioperative bleeding complications and weigh those risks in determining the safest perioperative strategy. We aimed to summarize and provide our opinion about the recommendations from the recent 8th edition of the American College of Chest Physicians (ACCP) guidelines for the perioperative management of antithrombotic therapy.

D-dimer testing to determine the duration of anticoagulant therapy

PURPOSE OF REVIEW

The optimal duration of oral anticoagulation after a first idiopathic venous thromboembolism is uncertain. Recent prospective observational studies show that D-dimer levels have a predictive value for the risk of recurrence. D-dimer testing may help in assessing the individual need for prolonged anticoagulation.

RECENT FINDINGS

The recently published Prolong study investigated 608 patients with a first unprovoked venous thromboembolism who had received oral anticoagulation for at least 3 months. D-dimer testing was performed 1 month after anticoagulation withdrawal. Patients with normal D-dimer (n = 385) did not resume anticoagulation. Patients with abnormal D-dimer were randomized to resume (n = 103) or not resume (n = 120) anticoagulation. All patients were followed for an average of 1.4 years. Study outcomes occurred in 6.2% of patients with normal D-dimer, and in 15.0% and 2.9% of those with abnormal D-dimer who were allocated to stop or to resume anticoagulation, respectively.

SUMMARY

Patients with an abnormal D-dimer measured 1 month from anticoagulation withdrawal have a significant incidence of recurrent venous thromboembolism which is reduced by resumption of anticoagulation. The risk of recurrence in patients with normal D-dimer is significantly lower. D-dimer testing can be used to regulate the duration of anticoagulation.

Safety of intravitreal injections in patients receiving warfarin anticoagulation

PURPOSE

To evaluate the safety of intravitreal Macugen (OSI/Eyetech, New York, New York, USA) injections among patients receiving warfarin anticoagulation.

DESIGN

Retrospective chart review.

METHODS

A search was conducted for patients treated with intravitreal Macugen for choroidal neovascularization resulting from age-related macular degeneration (AMD). Inclusion criteria included patients receiving warfarin anticoagulation in whom therapy was maintained.

RESULTS

The review identified 31 patients (32 eyes) who underwent 102 intravitreal Macugen injections while receiving warfarin anticoagulation. The mean and median number of Macugen injections per patient was three. No intraoperative or immediate postoperative hemorrhagic complications were noted. One patient experienced an acute submacular hemorrhage 35 days after the third Macugen injection. There were no other hemorrhagic events among the remaining patients.

CONCLUSIONS

The retrospective chart review of patients treated with intravitreal Macugen for choroidal neovascularization resulting from AMD while receiving warfarin therapy suggests that patients may undergo intravitreal injections safely without cessation of anticoagulation therapy.

Challenges in managing anticoagulant therapy in patients with heart valve prostheses

There is a wide array of recommendations for the management of anticoagulant therapy in patients with mechanical heart valves. The optimal intensity of vitamin K antagonists, management of patients during noncardiac surgery and use of anticoagulants during pregnancy are all ongoing matters of debate. In this review, we discuss the various studies on these topics and the different guidelines. Based on these, literature recommendations for daily clinical practice are formulated.

Review of the rebound phenomenon in new anticoagulant treatments

BACKGROUND

The launch of new anticoagulant treatments has sparked debate as to the optimal drug to use for primary prevention of venous thromboembolism (VTE) in major orthopaedic surgery, for the treatment of VTE, and for stroke prevention in atrial fibrillation, taking into account both efficacy and tolerability. Newer drugs such as fondaparinux and ximelagatran have shown improvements in short-term efficacy or convenience, but such effects may be offset by reduced tolerability. They also raise the question of a possible delayed increase in thromboembolic events after these drugs are stopped, the so-called 'rebound effect'.

OBJECTIVE

To review pharmacological and clinical data describing the rebound effect associated with new and standard anticoagulant drugs.

RESEARCH DESIGN AND METHODS

Computerized searches, covering the period 1960-2005 for the historical background and physiopathology review, and from 1999 to 2005 for the clinical trial analysis, were performed on BIOSIS, PubMed and clinicaltrials.gov databases. The terms 'rebound', 'anticoagulant', and 'heparin' were used. Only articles written in English were reviewed. Articles with drug interactions from other therapeutic classes or types of vascular surgery and commentary articles were excluded.

RESULTS

Available data in relation to a possible rebound phenomenon following cessation of active treatment are very limited. Results coming mainly from orthopaedic surgery trials suggest an increased rate of venous or arterial thromboembolic events with newer anticoagulants, compared with standard anticoagulant therapy. An increase in the rate of serious arterial adverse events has, for example, been observed in VTE patients treated with ximelagatran relative to those receiving warfarin/placebo (short-term exposure: 0.75% vs 0.26%, p < 0.05; long-term exposure: 1.70% vs 0.70%, p <or= 0.1).

CONCLUSIONS

Further clinical trials or meta-analyses are needed before we can determine whether the unexpected thromboembolic events found with newer anticoagulants can be linked to a rebound effect on treatment cessation.

Surgical delay in acute admissions on warfarin: are we doing enough?

Warfarin anti-coagulation can cause significant delay in acute surgical admissions. We reviewed fracture neck of femur patients operated over a period of 4 years in our unit. There was an average delay to surgery of 4.36 days in patients on warfarin as against an average delay of 1.78 days in patients not on warfarin (p < 0.001). The review was followed up with a questionnaire-based survey of consultant haematologists, and a general agreement towards a protocol-based use of vitamin K(1) was noted. The reasons for limited use of vitamin K(1) include the lack of studies and guidelines specifically addressing the pre-operative emergency admissions. We highlight a practical problem shared across different specialities and identify the areas for future studies.

High Rate of Recurrence in Renal Transplant Recipients after a First Episode of Venous Thromboembolism

BACKGROUND

No data are available about the optimal duration of oral anticoagulant therapy (OAT) after an episode of venous thromboembolism (VTE) occurring in renal transplant (RT) recipients. Our study was undertaken to evaluate the risk of VTE recurrence in patients developing a first episode of VTE after RT.

METHODS

Among 484 RT patients, 34 (7%) developed a first VTE: 28/34 VTE patients (Group 1) were prospectively studied, after stopping OAT. Group 1 was compared with a group of 84 patients without history of renal disease who had suffered from a first episode of VTE matched for age, sex and type of thrombotic event (Group 2) and with a matched group of 84 RT recipients with no history of VTE (Group 3). After OAT withdrawal, blood samples were obtained for thrombophilia and clotting activation markers (prothrombin fragment 1+2 (F1+2) and D-dimer plasma levels).

RESULTS

During follow-up, 14/28 patients of Group 1 and 8/84 patients of Group 2 experienced VTE recurrence (P < 0.0005). Homocysteine, F1+2 and D-dimer plasma levels were significantly higher in Group 1 than in Group 2 and 3 (P < 0.0001 and <0.05 respectively) for all the three parameters.

CONCLUSIONS

Our data outline the high risk of VTE recurrence in RT recipients. Strategies for VTE recurrence prevention are needed; Prolonged OAT, in spite of the high bleeding risk of RT patients, should be considered in this respect.

Low–Molecular-Weight-Heparins as Periprocedural Anticoagulation for Patients on Long-Term Warfarin Therapy: A Standardized Bridging Therapy Protocol

BACKGROUND

Over 2 million patients in North America are on warfarin anticoagulation therapy for prevention of thromboembolism. Suspension of warfarin therapy is often required to prepare patients for invasive procedures or surgeries. To protect these patients against thromboembolism while they are off warfarin, shorter-acting parenteral agents such as low-molecular-weight heparins (LMWHs) are often used. We conducted a retrospective observational study of our anticoagulation clinic patients to assess the safety and efficacy of LMWHs using a standardized protocol for periprocedural anticoagulation therapy.

METHODS

We included 69 consecutive patients who required interruption of their long-term warfarin therapy between August 2001 and August 2002, and were deemed by the treating physician to be at high enough risk for perioperative thromboembolism to justify bridging anticoagulation. We used a standard bridging therapy protocol in our anticoagulation clinic. Sixty-six patients received enoxaparin and three patients received tinzaparin for a mean duration of 7.7 days postoperatively. Outcomes were assessed for 30 days post-procedure. Safety outcomes included major bleeding and minor bleeding. Efficacy outcomes included thromboembolic event or death.

RESULTS

There were two major bleeding events, one minor bleeding event, and no cases of thromboembolism. Twelve patients experienced some bruising around the injection site.

CONCLUSIONS

LMWH administration using our standard outpatient bridging protocol for perioperative anticoagulation appears to be relatively safe and efficacious, offering an alternative to inpatient administration of intravenous unfractionated heparin (UFH). Our study provides additional evidence to the limited published observational data regarding the safety and efficacy of LMWH as bridging therapy in the perioperative and periprocedural setting. Large, multicenter, randomized controlled trials are necessary to fully assess the safety and efficacy of LMWH for perioperative anticoagulation.We conducted a retrospective observational study of 69 consecutive anticoagulation clinic patients on warfarin between August 2001 and August 2002, who were undergoing a procedure or surgery. The study was done to assess the safety and efficacy of an outpatient LMWH bridging protocol. Sixty-six patients received enoxaparin and three patients received tinzaparin for a mean duration of 3 days preoperatively and 7.7 days postoperatively. Outcomes were assessed for 30 days post-procedure. Safety outcomes included major bleeding and minor bleeding. Efficacy outcomes included thromboembolic event or death. There were two major bleeding events, one minor bleeding event, and no cases of thromboembolism. Twelve patients experienced some bruising around the injection site.

Predicting the risk of recurrence of venous thromboembolism

PURPOSE OF REVIEW

Although several clinical studies have investigated the effects of different treatment periods in subjects after a VTE event, the optimal duration of oral anticoagulation is still uncertain. Our review focused on studies that evaluated different risk factors that might be useful to stratify patients into categories at different risk for recurrence.

RECENT FINDINGS

The presence of irreversible, persistent, or transient risk factors affects the risk of recurrence. The inherited and acquired thrombophilic conditions that are associated with an increased risk of VTE may also be responsible for an increased risk of recurrence. Although this is still a matter of debate for the more common alterations, it is accepted for antithrombin, protein C, protein S deficiency, homozygous factor V Leiden, double heterozygosity, and antiphospholipid syndrome. It has been shown that high factor VIII levels are associated to increased risk of VTE recurrence. The presence of cancer is one of the most important persistent factors associated with VTE. Several studies have recently shown that D-dimer levels measured during and especially after oral anticoagulation interruption in subjects with a previous VTE, carriers or not of congenital thrombophilia have a high NPV for recurrence. The relation between the persistence of residual venous thrombosis and the risk of VTE recurrence has been investigated in two recent studies and both concluded that the persistence of a residual venous thrombosis is an important risk factor for recurrent thromboembolism and that its assessment may help clinicians modify the duration of anticoagulation in patients with DVT.

SUMMARY

Both the clinical aspects of the first VTE event and individual characteristics (such as associated diseases, inherited or acquired thrombophilic conditions, altered D-dimer results, or the presence of residual venous thrombosis) concur in determining the recurrence risk of each patient. Whether the evaluation of these risk factors may help to tailor the secondary prevention treatment in each patient should be assessed by specifically designed intervention studies.

Clotting activation after oral anticoagulant therapy discontinuation

A hypercoagulable state has been reported in some patients treated for venous thromboembolism (VTE) after oral anticoagulant treatment (OAT) discontinuation. It is unclear whether this is a risk factor for thrombosis recurrence. We investigated 139 patients with VTE and followed them up for a median of 20.5 months (6-90 months) to evaluate whether fragment 1 + 2 (F1 + 2) plasma levels are prognostic for VTE recurrence and to confirm clotting activation after OAT withdrawal. Fourteen patients had recurrences during the follow-up. F1 + 2 was measured the day before OAT withdrawal (T0) and 4 weeks later (T1) and its levels were similar in patients with spontaneous VTE versus those with transient risk factors for VTE. F1 + 2 levels increased from T0 to T1 (P < 0.0005). At T1, F1 + 2 values were significantly higher in patients with recurrence than in those without (P < 0.005). The negative predictive value of normal levels of F1 + 2 at T1 was 95%. In carriers of thrombophilic conditions no correlation was found between F1 + 2 levels and VTE recurrence. The results of this study confirm clotting activation after OAT discontinuation and suggest that higher F1 + 2 plasma levels are an independent risk factor for VTE recurrence.

The management of anticoagulants in the periendoscopic period for patients with atrial fibrillation: a decision analysis

PURPOSE

The management of patients who undergo endoscopy while being treated with warfarin is challenging. We used decision analysis to determine the preferred strategy to manage anticoagulants in the periendoscopic period.

METHODS

We designed a Markov model to estimate costs and quality-adjusted survival during a 10-year period in patients with nonvalvular atrial fibrillation undergoing screening colonoscopy. We compared six alternatives to the continue-warfarin strategy, which was to perform colonoscopy while the patient was taking full-dose warfarin. The hold-warfarin strategy was to stop warfarin 5 days before the colonoscopy. The repeat endoscopy strategy was to continue warfarin for a diagnostic colonoscopy, followed by a repeat procedure after cessation of warfarin if polypectomy was required. The dose-reduction strategy was to reduce the warfarin dose before colonoscopy. The low molecular weight heparin strategy was to administer subcutaneous low molecular weight heparin for 2 days before and 2 days after colonoscopy. The unfractionated heparin strategy was to administer intravenous unfractionated heparin for 2 days before and 2 days after the procedure. The vitamin K strategy was to hold warfarin for 4 days and to administer vitamin K if the international normalized ratio (INR) exceeded 2.0 the day before the procedure, or low molecular weight heparin if the INR was less than 1.5.

RESULTS

For screening colonoscopy, assuming that polyps would be removed in 35% of examinations, the hold-warfarin and dose-reduction arms were both cost-effective strategies. The hold-warfarin arm was most cost-effective if the likelihood of polypectomy exceeded 60%, or if there was a low risk of stroke despite atrial fibrillation. The continue-warfarin strategy was preferred if the probability of polypectomy was 1% or less.

CONCLUSION

Temporary warfarin cessation or halving the warfarin dose for several days before endoscopy was the preferred strategy for most patients. Periendoscopic heparin therapy was not cost-effective for patients with nonvalvular atrial fibrillation.