Triple antithrombotic therapy is the independent predictor for the occurrence of major bleeding complications: analysis of percent time in therapeutic range

Comparison of early clinical outcomes between dual antiplatelet therapy and triple antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention

Background and objective

Most Asian patients with atrial fibrillation (AF) who undergo percutaneous coronary intervention (PCI) receive only dual antiplatelet therapy (DAPT) without oral anticoagulants (vitamin K antagonists [VKA] or non-VKA oral anticoagulants [NOAC]). However, it has not been fully investigated whether the DAPT results in better clinical outcomes in the early period after PCI than the standard triple therapy with VKA or NOAC.

Methods

We analyzed the claims records of 11,039 Korean AF population who had PCI between 2013 and 2018. Patients were categorized according to the post-PCI antithrombotic therapy as VKA-based triple therapy (VKA-TT), NOAC-based triple therapy (NOAC-TT), and DAPT groups. After baseline adjustment using inverse probability weighting, we compared the risks of ischemic endpoints (ischemic stroke, myocardial infarction, and all-cause mortality) and major bleeding at 3 months post-PCI.

Results

Ischemic stroke, MI, and all-cause mortality occurred in 105, 423, and 379 patients, respectively, and 138 patients experienced major bleeding. The DAPT group was associated with a lower risk of ischemic stroke and major bleeding (hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.37–0.84) compared to the VKA-TT group, despite no significant differences in the risks of MI and all-cause mortality. In contrast, the DAPT group demonstrated no significant difference in the risks for ischemic endpoints compared to the NOAC-TT group. Additionally, the DAPT group had a numerically lower risk of major bleeding than the NOAC-TT group but this was not statistically significant (HR 0.69, 95% CI 0.45–1.07).

Conclusions

An outcome benefit of DAPT was observed in the early period after PCI compared to the VKA-TT, but not against NOAC-TT users among the Asian AF population. Given the potential long-term benefits of NOACs, greater efforts should be made to increase compliance in clinical practice with proper combination therapy with NOAC after PCI.

Safety and Efficacy Evaluation of Antithrombotic Therapy with Rivaroxaban and Clopidogrel After PCI in Chinese Patients

Objective

To investigate the efficacy and safety of the antithrombotic therapy using the oral anticoagulant rivaroxaban and clopidogrel in Chinese patients with acute coronary syndrome complicated with atrial fibrillation after percutaneous coronary intervention.

Methods

A total of 100 patients were selected. Patients were randomly divided into two groups: the treatment group (rivaroxaban group) received a therapy of rivaroxaban and clopidogrel. The control group (warfarin group) receivied a combined treatment of warfarin, clopidogrel, and aspirin. The primary outcome endpoint was evaluated based on the adverse cardiac and cerebrovascular events within 12 months.

Results

A total of 8 (8.00%) main adverse cardiac and cerebrovascular events occurred during the 12 months of follow-up, including 5 (9.80%) in the warfarin group and 3 (6.10%) in the rivaroxaban group. The risk of having main adverse cardiac and cerebrovascular events in the two groups was comparable (P = 0.479). A total of 9 patients (9.00%) were found to have bleeding events, among which 8 patients (15.7%) were in the warfarin group, whereas only 1 patient (2.00%) was in the rivaroxaban group. Therefore, the risk of bleeding in the warfarin group was significantly higher than that in the rivaroxaban group (P = 0.047).

Conclusions

In Chinese patients with acute coronary syndrome complicated with atrial fibrillation, the efficacy of the dual therapy of oral anticoagulant rivaroxaban plus clopidogrel after percutaneous coronary intervention was similar to that of the traditional triple therapy combined with warfarin, aspirin and clopidogrel, but it has a better safety property, which has potential to widely apply to antithrombotic therapy after PCI

Triple therapy after PCI - Warfarin treatment quality and bleeding risk

Background

A combination of warfarin, aspirin and clopidogrel is indicated after percutaneous coronary intervention (PCI) in some patients, despite the higher risk of bleeding inferred by this triple therapy.

Objectives

Whether the treatment quality of warfarin measured by iTTR (individual time within therapeutic INR range) is associated with bleeding complications during triple therapy after PCI.

Methods

A retrospective register study consisting of 601 triple treated PCI patients from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). The cohort was cross-matched with the Swedish Patient Registry for background characteristics and bleeding complications up to 6 months after PCI using ICD10 codes, the Prescribed Drug Registry for ongoing medications, and the national oral anticoagulation registry Auricula for warfarin treatment quality. The patients were grouped into four iTTR groups: <50%, 50–69.9%, 70–84.9% and >85% as well as iTTR above or below 70%.

Results

Of 601 patients, 39 (6.5%) had a bleeding complication (type 2 according to BARC). Bleeding was more common for iTTR<70% compared to iTTR>70%, 28 (9.3%) vs. 11 (3.7%) (p = 0.005). The bleeding frequency increased gradually from the best group, iTTR>85% with four bleeders (3.3%) up to 17 bleeders (13.3%) in the worst group with iTTR<50% (p = 0.003), with a corresponding bleeding rate per 100 treatment years of 8.0 and 44.9, respectively. In multivariate analysis low BMI, HR 1.11 (95% CI 1.01–1.22), a medical history of anemia HR 3.17 (1.16–8.69) and iTTR < 70% HR 2.86 (1.25–6.53) increased the risk of bleeding.

Conclusion

Triple therapy after PCI confers a high risk of bleeding events. Warfarin treatment quality measured by iTTR as well as a medical history of anemia are strong independent predictors of bleeding in these patients. Physicians should pay more attention to iTTR after PCI.

Safety and efficacy of anti-thrombotic regimens in patients with percutaneous coronary intervention requiring oral anticoagulation: A traditional and network meta-analysis

BACKGROUND

Previous reports have been inconsistent in generating a consensus for optimal treatment strategy for patients with percutaneous coronary intervention (PCI) who also require oral anticoagulation (OAC). We conducted a traditional and network meta-analysis to evaluate the safety and efficacy of anti-thrombotic regimens in this subset of patients.

METHODS

30 articles were recovered through preferred reporting items for systematic reviews and meta-analyses (PRISMA) using MEDLINE, EMBASE and Cochrane Central Register of Controlled Clinical Trials (CENTRAL) from inception to December 2016.

RESULTS

Dual antiplatelet therapy (DAPT) was found to be the safest treatment modality when compared to triple therapy (TT) or combination of OAC and single antiplatelet agent (OAC+SAP) [Major bleeding: (DAPT vs OAC+SAP: odds ratio (OR), 0.53; 95% credible interval (CrI), 0.30-0.91) (DAPT vs TT: OR, 0.45; 95% CrI, 0.31-0.64)]. There were no significant differences in major adverse cardiovascular events (MACE), myocardial infarction (MI), cardiovascular (CV) or total survival, stent thrombosis or target vessel revascularization (TVR) amongst the three treatment arms. TT was ranked superior for stroke reduction (SUCRA, 69%) followed by OAC+SAP and DAPT. When traditional analysis was adjusted for randomized data, OAC+SAP was equivalent to TT with regards to stroke (OR, 0.74; 95% confidence interval (CI), 0.38-1.46; p=0.39) and showed significant reduction in MACE and total mortality.

CONCLUSION

DAPT was found to be the safest and equally effective regimen when compared to TT and OAC+SAP. However this strategy bears considerable risk to patients with high thromboembolic risk. This issue can be encountered by using OAC+SAP as an alternative of TT in patients with intermediate to high stroke risk and intermediate to high bleeding propensity.

Major bleeding events in Jordanian patients undergoing percutaneous coronary intervention (PCI): Incidence, associated factors, impact on prognosis, and predictability of the CRUSADE bleeding risk score. Results from the First Jordanian PCR (PCR1)

Objective:

Determine the incidence of major bleeding events, their risk factors, and their impact on prognosis in Jordanian patients undergoing percutaneous coronary intervention (PCI). Evaluate the ability of the CRUSADE bleeding risk score (BRS) to predict major bleeding.

Methods:

Major bleeding events were defined according to the CRUSADE classification and their incidence was evaluated from hospital admission to one year of follow up. The CRUSADE bleeding risk score was calculated for each patient during the index admission. Incidence of major bleeding events was evaluated in each of the bleeding score quintiles. JoPCR1 is a prospective, observational, multicenter registry of consecutive patients who underwent PCI at 12 tertiary care centers in Jordan. A case report form was used to record data prospectively at hospital admission, at discharge, and at 1 and 12 months of follow-up.

Results:

The study included 2426 consecutive patients who underwent PCI. During the index hospitalization, major and minor bleeding events occurred in 0.95% and 2.6% of patients, respectively. Multivariate analysis showed that only two variables were significantly associated with major bleeding: female gender (OR=3.7; 95% CI 1.6, 8.5; p=0.002) and past history of cardiovascular disease (OR=2.6; 95% CI 1.1, 5.9; p=0.026). Patients who had in-hospital major bleeding events had higher cardiac mortality during index hospitalization (13.0% vs. 0.7%, p<0.005) and at one year of follow up (13.0% vs. 1.8%, p<0.005) compared to those who had no such events. Receiver operating characteristic curve analysis showed that the CRUSADE BRS has a high ability to predict major bleeding.

Conclusion:

Major bleeding events were uncommon in this ME registry of a contemporary cohort of patients undergoing PCI but were associated with a higher mortality rate compared with those who did not have major bleeding events. CRUSADE BRS was highly predictive of the incidence of major bleeding events.

Adequate time in therapeutic INR range using triple antithrombotic therapy is not associated with long-term cardiovascular events and major bleeding complications after drug-eluting stent implantation

BACKGROUND

Triple antithrombotic therapy increases the risk of bleeding events in patients undergoing percutaneous coronary intervention (PCI) compared with dual anti-platelet therapy (DAPT). However, whether warfarin control is associated with reduced cardiovascular events and major bleeding events in patients undergoing PCI with triple antithrombotic therapy is uncertain.

METHODS

We investigated 1207 consecutive patients who underwent PCI between 2004 and 2011. Major bleeding complications and major adverse cardiac and cerebrovascular events (MACCE) defined as all-cause death, acute coronary syndrome, target vessel revascularization, and stroke were compared between groups of patients who received either triple antithrombotic therapy or DAPT.

RESULTS

Triple antithrombotic therapy was administered to 95 (7.9%) patients. The mean international normalized ratio of prothrombin time (PT-INR) was 1.8. The target PT-INR level was set between 1.6 and 2.6 and the ratio (%) of time in the therapeutic range (TTR) was calculated. The median TTR was 78.4% (interquartile range, 67.4-87.6%). Kaplan-Meier survival curves showed that warfarin therapy was not associated with MACCE (p=0.89) and major bleeding (p=0.80). Multivariable Cox regression analysis revealed that triple antithrombotic therapy was not an independent predictor of MACCE and major bleeding.

CONCLUSIONS

Triple antithrombotic therapy does not increase the occurrence of MACCE and major bleeding complications, if the warfarin dose is tightly controlled with a lower INR.

Use of Chronic Oral Anticoagulation and Associated Outcomes Among Patients Undergoing Percutaneous Coronary Intervention

Background

Contemporary rates of oral anticoagulant (OAC) therapy and associated outcomes among patients undergoing percutaneous coronary intervention (PCI) have been poorly described.

Methods and Results

Using data from an integrated health care system from 2009 to 2014, we identified patients on OACs within 30 days of PCI. Outcomes included in‐hospital bleeding and mortality. Of 9566 PCIs, 837 patients (8.8%) were on OACs, and of these, 7.9% used non–vitamin K antagonist agents. OAC use remained stable during the study (8.1% in 2009, 9.0% in 2014; P=0.11), whereas use of non–vitamin K antagonist agents in those on OACs increased (0% in 2009, 16% in 2014; P<0.01). Following PCI, OAC‐treated patients had higher crude rates of major bleeding (11% versus 6.5%; P<0.01), access‐site bleeding (2.3% versus 1.3%; P=0.017), and non–access‐site bleeding (8.2% versus 5.2%; P<0.01) but similar crude rates of in‐hospital stent thrombosis (0.4% versus 0.3%; P=0.85), myocardial infarction (2.5% versus 3.0%; P=0.40), and stroke (0.48% versus 0.52%; P=0.88). In addition, prior to adjustment, OAC‐treated patients had longer hospitalizations (3.9±5.5 versus 2.8±4.6 days; P<0.01), more transfusions (7.2% versus 4.2%; P<0.01), and higher 90‐day readmission rates (22.1% versus 13.1%; P<0.01). In adjusted models, OAC use was associated with increased risks of in‐hospital bleeding (odds ratio 1.50; P<0.01), 90‐day readmission (odds ratio 1.40; P<0.01), and long‐term mortality (hazard ratio 1.36; P<0.01).

Conclusions

Chronic OAC therapy is frequent among contemporary patients undergoing PCI. After adjustment for potential confounders, OAC‐treated patients experienced greater in‐hospital bleeding, more readmissions, and decreased long‐term survival following PCI. Efforts are needed to reduce the occurrence of adverse events in this population.

Rationale and design of the SAFE-A study: SAFety and Effectiveness trial of Apixaban use in association with dual antiplatelet therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention

BACKGROUND

Patients with atrial fibrillation who undergo coronary stenting require triple antithrombotic therapy, including aspirin, a P2Y₁₂ inhibitor, and anticoagulation, to prevent both stroke and stent thrombosis. However, triple therapy may increase the risk of bleeding complications. The optimal management of triple therapy still presents a challenge in these patients.

HYPOTHESIS

We hypothesized that 1-month P2Y₁₂ inhibitor treatment after drug-eluting stent (DES) implantation, as compared with 6-month P2Y₁₂ inhibitor treatment, in combination with aspirin and apixaban, would be associated with a decrease in the incidence of bleeding complications in patients with atrial fibrillation who undergo DES implantation.

DESIGN

SAFE-A (UMIN Clinical Trials Registry Number: UMIN000015923) is a multicenter, prospective, randomized, open-label, blinded-endpoint, parallel-group, comparative study that was designed to compare the safety and efficacy of short-duration treatment with a P2Y₁₂ inhibitor in combination with aspirin and apixaban in subjects with non-valvular atrial fibrillation who undergo DES implantation. A total of 600 subjects will be randomized in a 1:1 fashion to either 1-month or 6-month P2Y₁₂ inhibitor therapy in combination with aspirin and apixaban. The primary endpoint is the incidence of all bleeding complications occurring within 12 months.

CONCLUSION

The SAFE-A study is the first randomized controlled trial to compare 1-month vs. 6-month P2Y₁₂ inhibitor therapy in combination with aspirin and apixaban, in patients with atrial fibrillation who undergo DES implantation. This study will provide data that may guide the optimal management of triple antithrombotic therapy.

1-methylnicotinamide and its structural analog 1,4-dimethylpyridine for the prevention of cancer metastasis

Background

1-methylnicotinamide (1-MNA), an endogenous metabolite of nicotinamide, has recently gained interest due to its anti-inflammatory and anti-thrombotic activities linked to the COX-2/PGI₂ pathway. Given the previously reported anti-metastatic activity of prostacyclin (PGI₂), we aimed to assess the effects of 1-MNA and its structurally related analog, 1,4-dimethylpyridine (1,4-DMP), in the prevention of cancer metastasis.

Methods

All the studies on the anti-tumor and anti-metastatic activity of 1-MNA and 1,4-DMP were conducted using the model of murine mammary gland cancer (4T1) transplanted either orthotopically or intravenously into female BALB/c mouse. Additionally, the effect of the investigated molecules on cancer cell-induced angiogenesis was estimated using the matrigel plug assay utilizing 4T1 cells as a source of pro-angiogenic factors.

Results

Neither 1-MNA nor 1,4-DMP, when given in a monotherapy of metastatic cancer, influenced the growth of 4T1 primary tumors transplanted orthotopically; however, both compounds tended to inhibit 4T1 metastases formation in lungs of mice that were orthotopically or intravenously inoculated with 4T1 or 4T1-luc2-tdTomato cells, respectively. Additionally, while 1-MNA enhanced tumor vasculature formation and markedly increased PGI₂ generation, 1,4-DMP did not have such an effect. The anti-metastatic activity of 1-MNA and 1,4-DMP was further confirmed when both agents were applied with a cytostatic drug in a combined treatment of 4T1 murine mammary gland cancer what resulted in up to 80 % diminution of lung metastases formation.

Conclusions

The results of the studies presented below indicate that 1-MNA and its structural analog 1,4-DMP prevent metastasis and might be beneficially implemented into the treatment of metastatic breast cancer to ensure a comprehensive strategy of metastasis control.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0389-9) contains supplementary material, which is available to authorized users.

Low On-Treatment Platelet Reactivity Predicts Long-Term Risk of Bleeding After Elective PCI

BACKGROUND

Bleeding after percutaneous coronary interventions (PCI) is an important complication with impact on prognosis.

AIM

To evaluate the predictive value of enhanced platelet responsiveness to dual antiplatelet therapy with aspirin and clopidogrel, for bleeding, after elective PCI.

METHODS AND RESULTS

We performed multiple electrode aggregometry (MAE) platelet functional tests induced by arachidonic acid (ASPI) and adenosine-diphosphate (ADP) before PCI, and 24 hours after PCI, in 481 elective PCI patients who were followed-up for an average of 15.34 ± 7.19 months. Primary end point was the occurrence of any bleeding, while ischemic major adverse cardiovascular event (MACE) was a secondary endpoint. The incidence of total, BARC ≤ 2, and BARC ≥ 3 bleeding, according to BARC classification, was 19, 18, and 1%, respectively. Groups with any, and BARC ≤ 2 bleeding, had a lower average value of MAE ADP test after 24 hours, compared to the group without bleeding: 45.30 ± 18.63 U versus 50.99 ± 19.01 U; P = 0.005; and 45.75 ± 18.96 U versus 50.99 ± 18.99 U; P = 0.01; respectively. Female gender (HR 2.11; CI 1.37-3.25; P = 0.001), previous myocardial infarction (HR 0.56; CI 0.37-0.85; P = 0.006), lower body mass (HR 0.78; CI 0.62-0.98; P = 0.03), and MAE ADP test after 24 hours (HR 0.75; CI 0.61-0.93; P = 0.009) were the independent predictors for any bleeding by Cox univariate analysis. After adjustment, MAE ADP test after 24 hours, was the only independent predictor for any (HR 0.7; CI 0.56-0.87; P = 0.002), and BARC ≤ 2 (HR 0.71; CI 0.56-0.89; P = 0.003) bleeding, by Cox multivariate analysis.

CONCLUSION

MAE ADP test before and after PCI, was associated with any, and BARC ≤ 2 bleeding after elective PCI.

Antithrombotic therapy after percutaneous coronary intervention in patients requiring oral anticoagulant treatment. A meta-analysis

AIM

The aim of this meta-analysis was to evaluate the benefits and risks of triple therapy (TT) compared with dual therapy (DT) for patients with an indication for anticoagulation who had undergone percutaneous coronary intervention.

BACKGROUND

An increasing number of patients undergoing percutaneous coronary intervention have atrial fibrillation or other indications for oral anticoagulants. For these patients, TT (oral anticoagulants plus aspirin and clopidogrel) is indicated, but this type of treatment increases the risk of bleeding. Thus, it remains controversial whether these patients can benefit more from TT.

METHODS

We identified 23 clinical trials that compared TT with DT (aspirin and clopidogrel or oral anticoagulants plus a single antiplatelet drug) after percutaneous coronary intervention in patients undergoing oral anticoagulant (OAC) treatment. The follow-up period ranged from 1 month to 25 months. Two coauthors independently recorded the data on interventions and on the occurrence of major adverse cardiac events (MACE), all-cause death, and major bleeding events.

RESULTS

The 23 clinical trials comprised 22,212 participants. Our analysis was feasible because the baseline characteristics and grouping criteria were similar in all groups. The results indicated that TT was more efficacious than DT [dual antiplatelet (DAPT) or OAC + single antiplatelet] in reducing MACE/stroke (RR = 0.76, 95 % CI: 0.70-0.83; p < 0.00001 and RR = 0.67, 95 % CI: 0.59-0.75; p < 0.00001, respectively) There was a significant reduction in all-cause death in the TT regimen compared with the DT regimen (RR = 0.64, 95 % CI: 0.56-0.73; p < 0.00001 and RR = 0.48, 95 % CI: 0.39-0.58; p < 0.00001, respectively). In a subgroup analysis without retrospective studies, we found that there was no significant difference between TT and DT with regard to MACE/stroke (RR = 1.06, 95 % CI: 0.88-1.27; p = 0.54 and RR = 0.95, 95 % CI: 0.79-1.14; p = 0.58, respectively) and all-cause death (RR = 0.84, 95 % CI: 0.63-1.12; p = 0.24 and RR = 1.13, 95 % CI: 0.78-1.64; p = 0.51, respectively). We also found that TT significantly increased the risk of major bleeding compared with DAPT (RR  = 1.36; 95 % CI: 1.17-1.58; p < 0.0001). However, there was no difference between TT and OAC + single antiplatelet agent (RR = 0.96; 95 % CI: 0.75-1.21; p = 0.71). Finally, in the comparison between TT and OAC + clopidogrel, there were no differences in major bleeding events, MACE and stroke, and all-cause death.

CONCLUSION

Our analysis found no statistically significant difference between TT and DT with regard to all-cause death and MACE/stroke risk. At the same time, the available data demonstrated that TT increased the risk of major bleeding. If the international normalized ratio is in the target range, the risk of bleeding may be lowered. The data from Asian countries were limited, and therefore we could not assess the difference between TT and DT in Asian populations. Finally,on the basis of our analysis, we do not recommend TT as conventional treatment for patients taking OACs and undergoing percutaneous coronary intervention.

Oral anticoagulant therapy and bleeding events with vitamin K antagonists in patients with atrial fibrillation in a Hungarian county hospital

Background

Vitamin K antagonists, despite their tight therapeutic spectrum and the fear of bleeding complications, were long the most important drugs used in anticoagulant therapy. The aim of this study was to evaluate the quality of anticoagulant therapy and its relation with bleedings in everyday clinical practice.

Material/Methods

We analyzed the data of 272 patients with non-valvular atrial fibrillation treated in our county hospital using retrospective data collection of the last 1008±384 days. The INR (International Normalized Ratio) values and the time in therapeutic range (TTR) were analyzed. We asked patients about bleeding complications and searched the medical records.

Results

The TTR proved to be 64% and there was no statistically significant difference between that of 252 (92.7%) patients taking acenocoumarol and 20 (7.3%) on warfarin. Analyzing various factors leading to TTR under 70%, we found that none of them have a significant impact. Significantly more bleeding events occurred in the first 3 months after the initiation of anticoagulant therapy and in patients with TTR under 70%, but the latter was not significant after adjustment for factors influencing bleeding (OR 1.607, CI 0.571–4.522, p=0.392).

Conclusions

Although the present study’s TTR values were similar to those found in the warfarin branch of various large-scale international trials and in real-life settings, further improvement of vitamin K antagonist therapy are necessary. As the possibilities for this are limited, we believe that the new type anticoagulant agents have a place in everyday clinical practice.

Primary percutaneous coronary intervention and bleeding risk in the era of drug-eluting stent: a long-term cohort study

Data of long-term efficacy and safety including bleeding risk associated with antithrombotic regimens after primary percutaneous coronary intervention (PCI) using first-generation drug-eluting stent (1st DES) are scarce. Consecutive 422 patients with ST-elevation myocardial infarction (STEMI) underwent primary PCI with DES (285 patients), bare metal stent (BMS, 58 patients) or balloon angioplasty (BA 79 patients). At a median follow-up of 44 months, major cardiovascular events were significantly lower for 1st DES compared with BMS and BA (11.9 vs. 25.9 vs. 16.5 %, p = 0.027). Cardiac death, recurrent myocardial infarction and target lesion revascularization (TLR), differed among the groups (DES 8.8 %; BMS 13.8 %; BA 17.7 %; p = 0.019), although the superiority of DES subsided beyond 1 year by increased late TLRs. Major bleedings were not higher in DES than in BMS and BA (4.6 vs. 6.9 vs. 1.5 %, p = 0.252). Multivariate logistic regression analysis revealed that both dual antiplatelet therapy (DAPT) >24 months and indefinite oral anticoagulation (OAC) were associated with a major bleeding. The risk was even greater with triple antithrombotic therapy (odds ratio 19.5; 95 % confidence interval 3.73-102.07; p < 0.0001). 1st DES showed favorable overall long-term clinical outcome in STEMI, with an inherent limitation of an increased risk of late TLR. Prolonged DAPT and OAC synergistically increase the risk of major bleeding after primary PCI.

Impact of rivaroxaban compared with warfarin on the coagulation status in Japanese patients with non-valvular atrial fibrillation: a preliminary analysis of the prothrombin fragment 1+2 levels

BACKGROUND

Rivaroxaban is an oral anticoagulant that effectively prevents thromboembolic complications using fixed doses without requiring laboratory monitoring. In this study, we aimed to examine the coagulation status in patients with non-valvular atrial fibrillation (NVAF) treated with rivaroxaban compared with warfarin.

METHODS AND RESULTS

The study group consisted of 85 consecutive Japanese patients with NVAF who received rivaroxaban (n=33) or warfarin (n=52) from June 2013 to February 2014. We compared the coagulation status between the rivaroxaban and warfarin treatments. The prothrombin time (PT) values did not significantly differ between the two groups. However, the prothrombin fragment 1+2 (F1+2) level, a marker of thrombin generation, was significantly higher in the rivaroxaban group than the warfarin group (202±88pmol/l vs. 114±79pmol/l, p<0.001). Next, we collected blood samples from 18 patients taking rivaroxaban at 3h and 15h after the drug intake and evaluated the time-dependent changes in the coagulation status. The PT values at 3h after the drug intake were significantly more prolonged than those at 15h (p<0.001). However, there were no significant differences in the F1+2 levels between the two time points (194±73pmol/l [at 3h] vs. 165±61pmol/l [at 15h], p=0.112).

CONCLUSIONS

Our preliminary results suggest that the thrombin generation level is stable regardless of the time elapsed after rivaroxaban intake, and warfarin treatment may inhibit thrombin generation more aggressively than rivaroxaban.