Fiix-prothrombin time (Fiix-PT) differs from traditional PT in being affected by reduced factor (F) II or FX only. In the randomized controlled Fiix-trial, patients on warfarin monitored with Fiix-PT ...(Fiix-warfarin patients) had fewer thromboembolisms (TE), similar major bleeding (MB) and more stable anticoagulation than patients monitored with PT (PT-warfarin patients). In the current Fiix-trial report we analyzed how reduced anticoagulation variability during Fiix-PT monitoring was reflected in patients with TE or bleeding. Data from 1143 randomized patients was used. We analyzed the groups for anticoagulation intensity (time within target range; TTR), international normalized ratio (INR) variability (variance growth rate B
1
; VGR) and dose adjustment frequency. We assessed how these parameters associated with clinically relevant vascular events (CRVE), ie TE or MB or clinically relevant non-MB. TTR was highest in Fiix-warfarin patients without CRVE (median 82%;IQR 72–91) and lowest in PT-warfarin patients with TE (62%;56–81). VGR was lowest in Fiix-warfarin patients without CRVE (median VGR B
1
0.17; 95% CI 0.08–0.38) and with TE (0.20;0.07–0.26) and highest in PT-warfarin patients with TE (0.50;0.27–0.90) or MB (0.59;0.07–1.36). The mean annual dose adjustment frequency was lowest in Fiix-warfarin patients with TE (mean 5.4;95% CI 3.9–7.3) and without CRVE (mean 6.0; 5.8–6.2) and highest in PT-warfarin patients with TE (14.2;12.2–16.3). Frequent dose changes predicted MB in both study arms. Compared to patients monitored with PT, high anticoagulation stability in Fiix-warfarin patients coincided with their low TE rate. Those with bleeding had high variability irrespective of monitoring method. Thus, although further improvements are needed to reduce bleeding, stabilization of anticoagulation by Fiix-PT monitoring associates with reduced TE.
Rapid fluctuations in factor VII during warfarin anticoagulation change the international normalised ratio (INR) but contribute little to the antithrombotic effect. We aimed to assess non-inferiority ...of anticoagulation stabilisation with a warfarin monitoring method affected only by factors II and X (Fiix-prothrombin time Fiix-PT) compared with standard PT-INR monitoring that includes factor VII measurement as well.
The Fiix trial was a single centre, double-blind, prospective, non-inferiority, randomised controlled clinical trial. Ambulatory adults on warfarin with an INR target of 2-3 managed by an anticoagulation dosing service using software-assisted dosing at the National University Hospital of Iceland, Reykjavik, Iceland, were eligible for inclusion in this study. We excluded patients undergoing electroconversion and nursing home residents. Patients were randomly assigned (1:1) to either the Fiix-PT monitoring group or the PT monitoring group by block randomisation. A blinded research INR (R-INR) based on results of the respective test was reported to the dosing staff. Participants were contacted by a study nurse at 4-week intervals to elicit information about thromboembolism or bleeding otherwise unknown to the anticoagulation management centre. The primary efficacy outcome was a composite of objectively diagnosed non-fatal and fatal arterial or venous thromboembolism, including myocardial infarction and transient ischaemic attacks, assessed in all eligible patients who were randomised (intention-to-monitor population). The safety endpoint was major bleeding or other clinically relevant bleeding, assessed in the per-protocol population. We assumed a 3% annual thromboembolism incidence and a non-inferiority margin of 2·5%. This trial is registered with ClinicalTrials.gov, number NCT01565239.
Between March 1, 2012, and Feb 28, 2014, we enrolled 1156 patients. 573 patients were assigned to Fiix-PT and 575 to PT-INR monitoring after exclusion of four patients from each group for various reasons. Median follow-up was 1·7 years (IQR 1·1-1·9). During days 1-720, ten (1·2% per patient year) thromboembolic events occurred in the Fiix-PT group versus 19 (2·3% per patient year) in the PT group (relative risk RR 0·52, 95% CI 0·25-1·13; pnon-inferiority<0·0001). Major bleeding occurred in 17 of 571 patients in the Fiix group (2·2% per patient year) versus 20 of 573 patients in the PT group (2·5% per patient year; RR 0·85, 0·45-1·61; pnon-inferiority=0·0034). Anticoagulation stability was improved with Fiix-PT monitoring as manifested by fewer tests, fewer dose adjustments, increased time in range and less INR variability than reported with standard PT monitoring.
Monitoring of warfarin with Fiix-PT improved anticoagulation and dosing stability and was clinically non-inferior to PT monitoring. Results from this trial suggest that during vitamin K antagonist treatment INR monitoring could be replaced by Fiix-PT and that this would lead to at least a non-inferior clinical outcome compared with monitoring with PT-INR.
Innovation Center Iceland, University of Iceland Science Fund, Landspitali Science Fund and Actavis.
Abstract
Women with Bernard-Soulier syndrome (BSS) are considered to be at high risk of serious bleeding during childbirth. Due to the frequently occurring platelet transfusion refractoriness, ...alternative prophylactic therapy is required. Using rotational thromboelastometry, we evaluated the whole blood coagulation profile of a pregnant woman with BSS before and after spiking ex vivo with different concentrations of recombinant activated factor VII (rFVIIa) and fibrinogen. As experiments suggested improved clotting with clinically applicable concentrations of both agents in a complementary manner, the findings were confirmed on blood from a non-pregnant woman and three men suffering from BSS. During delivery, bleeding refractory to platelets occurred and immediately following delivery she received both rFVIIa and fibrinogen intravenously. Immediate cessation of bleeding occurred, and no postpartum hemorrhage was seen. Another woman with BSS later also received the same rFVIIa and fibrinogen treatment prophylactically after delivery without any postpartum bleeding. Eventually, the first woman during her second delivery received the same treatment again prophylactically without any bleeding. No side effects were observed during these three deliveries. Our observations suggest that rFVIIa combined with fibrinogen may provide a beneficial clinical hemostatic effect partly by separate but complementary mechanisms.
Background: Traditional prothrombin time (PT) based international normalized ratio (INR) is often highly variable. Often this is caused by rapid factor VII reductions due to its short (4 hour) ...half-life. Thus, factor VII variation is an important confounder during vitamin K antagonist (VKA) dosing. Furthermore, prior studies have demonstrated that factor VII reductions only minimally influence the antithrombotic effect and bleeding risk of VKA, the clinical effect depending mainly on controlled reduction of factors II and X. Therefore, ignoring the influence of FVII during VKA monitoring has the potential to simplify management and outcome.
The Fiix prothrombin time (Fiix-PT) is a new modified PT that is only affected by reduced factors II and X. The Fiix-PT is not affected by variations in factor VII. Hence, the Fiix normalized ratio (Fiix-NR) fluctuates less than the standard standard PT-INR. In the double-blind randomized clinical Fiix-trial, published in 2015, monitoring of warfarin with with Fiix-PT (Fiix-NR) was compared to standard high time-in-range PT-INR monitoring. Fiix-NR monitoring led to improved time-in-range, reduced testing frequency, reduced dose-adjustment need and a 50% reduction in thromboembolism (TE). Bleeding did not increase and it occurred at a low rate in both trial arms. Subsequently starting on July 1st 2015 we replaced the PT-INR with Fiix-NR in our anticoagulation monitoring practice.
Aim: We compared anticoagulation outcome and dosing frequency during 12 months prior to switching from PT-INR based management (Pre-Fiix monitoring period) and during 12 months following switch to Fiix-NR monitoring (Fiix monitoring period).
Methods: This is a retrospective before and after study involving unselected patients managed at a single anticoagulation management service at the Landspitali University Hospital in Reykjavik, Iceland. All patients on warfarin during two consecutive twelve month periods were analysed irrespective of indication or anticoagulation target range. Pre-Fiix patients analysis was based on events occuring during months -12 to -1 before replacing the PT with Fiix PT and the Fiix patients´outcome was analysed during months +4 to +15. Three transitional months were excluded. All patients were dosed by specialized staff using the DAWN anticoagulation software®. Hospital chart diagnostic codes were reviewed for occurrence of TE or major bleeding (MB) during the two separate monitoring periods.Surrogate assessments included the number of tests, testing intervals and dose adjustment frequencies and will be analyzed later.
Results: During the Pre-Fiix period 2,345 patients were managed with PT-INR for 1,984 patient years (0.85 years/patient) and during the Fiix period 1,909 patients were managed with Fiix-NR for 1,643 patient years (0.86 y/pt). Indications for warfarin were identical during both periods (atrial fibrillation 57%, venous thromboembolism 26%, prosthetic heart valves 5% and other 12%). The INR target range during both periods was 2.0-3.0 in 92% and 2.5-3.5 in 6%. Clinical outcome with respect to TE and MB is shown in the figure. Overall the point estimates were suggestive of a 34-52% reduction of TE with Fiix-NR monitoring whereas major bleeding was similar. The reduction in untoward events in the Fiix group was statistically significant for composite new TE (OR 0.63;0.41-0.97) and total stroke (ischemic and hemorrhagic, OR 0.57;CI 0.33-0.98), mainly driven by reduced cerebral infarction. Intracranial bleeding occurred in 0.76% in the Pre-Fiix group and in 0.37% in the Fiix montoring group (n.s., OR 0.51;0.19-1.32). The median time-within-Target-range (TTR, Rosendaal method) was similar in both groups (75 vs 76%, respectively), despite dose adjustment frequency being reduced by 18% in the Fiix monitoring group (OR 0.82;CI 0.79-0.85, p <0.0001).
Conclusions: These results are in agreement with the results of the Fiix-trial and show that ignoring factor VII during VKA monitoring is safe and leads to reduction in thromboembolism without increasing bleeding. Although TTR was identical in both groups, the dose adjustment need was reduced possibly indicating that less anticoagulation variability in the Fiix-NR group explains reduced thromboembolism.
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Gudmundsdottir:Hart Biologicals Ltd: Consultancy, Patents & Royalties: Hart Biologicals Ltd is commercializing the Fiix-PT which will be ready for marketing in Europe in the beginning of year 2019 and possibly later that year in the USA. Patent fees will be paid to Fiix Diagnostics Ltd once the test is commercialized.; Fiix Diagnostics Ltd: Equity Ownership, Patents & Royalties: The Fiix prothrombin time (Fiix-PT) is a patented invention of P. T. Onundarson and B.R. Gudmundsdottir that is owned by Fiix Diagnostics Ltd, a start-up company founded by the inventors. . Onundarson:Hart Biologicals Ltd: Consultancy, Other: Hart Biologicals Ltd is commercializing the Fiix-PT which will be ready for marketing in Europe in the beginning of year 2019 and possibly later that year in the USA. Patent fees will be paid to Fiix Diagnostics Ltd once the test is commercialized.; Fiix Diagnostics Ltd: Equity Ownership, Patents & Royalties: The Fiix prothrombin time (Fiix-PT) is a patented invention of P. T. Onundarson and B.R. Gudmundsdottir that is owned by Fiix Diagnostics Ltd, a start-up company founded by the inventors. .
Abstract Cardiac surgery involving cardio pulmonary bypass (CPB) may be associated with development of a coagulopathy that increases risk of bleeding. In the present ex vivo study we investigated the ...influence of fibrinogen and rFVIIa, alone or in combination, on whole blood coagulation thromboelastometry using pre- and postoperative blood samples from 18 consecutive adult patients undergoing CPB surgery. Dynamic thromboelastometric clotting profiles were recorded using citrated whole blood activated with trace amounts of tissue factor (Innovin®, final dilution 1:17000). Blood samples were collected before surgery (control) and postoperative samples were obtained following in vivo neutralization of heparin with protamine sulphate. All blood samples were treated with heparinase to ensure neutralization of possible residual heparin effect. The post-operative blood samples were spiked with buffer, rFVIIa (2 µg/mL), fibrinogen (1 mg/mL), or the combination of rFVIIa and fibrinogen. Despite neutralization of heparin, CPB surgery left a measurable coagulopathy that was thromboelastometrically characterized by prolonged onset of clotting, reduced maximum velocity of clot formation (MaxVel), and decreased maximum clot firmness (MCF). Ex vivo spiking of the postoperative samples with rFVIIa shortened the clotting time. Fibrinogen also shortened the clotting time and, in addition, improved the MaxVel, and MCF. Finally, adding the combination of rFVIIa and fibrinogen to the postoperative samples corrected all thromboelastometric parameters to the preoperative range. In conclusion, the correction of whole blood clotting abnormalities that occurs with rFVIIa and/or fibrinogen suggests that future clinical trials on treatment of bleeding during CPB surgery should study the haemostatic effect of fibrinogen or possibly the combination of rFVIIa and fibrinogen.
Introduction: The Quick prothrombin time (PT) is equally sensitive to the influence of factors (F) II, VII and X but experiments suggest that it is mainly the influence of warfarin on factors (F) II ...and X that cause its anticoagulant effect. The new Fiix prothrombin time (Fiix-PT) differs from the PT in it being sensitive only to factors (F) II and X and not being sensitive at all to FVII activity in the test plasma. The Fiix-trial has demonstrated increased stability of warfarin anticoagulation and possibly improved efficacy when monitored with Fiix-PT compared to PT monitoring (unpublished data). However, as very low levels of vitamin K dependent (VKD) factors not measured with the Fiix-PT could possibly have deleterious effect on anticoagulation (AC) outcome, we measured the VKD coagulation factors in plasma obtained from patients on stable warfarin anticoagulation and during the first 30 days of warfarin treatment monitored either with the Fiix-PT or the PT.
Methods: In order to define stable anticoagulation in terms of coagulation factor activity, samples from patients enrolled in the Fiix trial and monitored either with Fiix-PT or PT were used. Frozen samples from 20 patients were obtained from each monitoring group. All the samples had been drawn from patients during very stable warfarin treatment (INR within range 2-3 for over 10 months by serial monitoring). Serial samples were also obtained from 10 patients in each group during days 1-30 of warfarin initiation. PT, Fiix-PT and VKD coagulation factors were measured. An INR was calculated for both PT and Fiix-PT.
Results: During stable AC, the median INR (range) was 2.5 (2.1-3.0) in the Fiix-group vs 2.4 (2.0-3.0) in the PT group (p=ns). The median (95% range) VKD factor percent coagulant activity was as follows in the stable Fiix-group vs the stable PT-group: FII 28 (19-40) vs 25 (18-40), FVII 48 (30-88) vs 42 (23-85), FIX 66 (41-85) vs 61 (36-79), and FX 15 (11-17) vs 15 (10-22). Although the medians tended to be higher in the Fiix group except for FX, p was n.s. for all. In patients starting on warfarin a stable Fiix-INR (defined as two INRs within target range) was reached on day 14 (median) in the Fiix group vs a stable PT-INR on day 11 in the PT controls. Following this, however, the PT-INR fluctuates more out of the INR target range than the Fiix-INR does. As shown in the figures, the earlier rise in INR in the PT group is mainly a reflection of a rapid fall in FVII activity. The FVII level decreases to a nadir of 20% in the Fiix group compared to a nadir of 30% in the PT monitoring group. Subsequently FII, FVII and FX fluctuate less in the Fiix-PT group than in the PT group. During the first 30 days 46% of Fiix-INRs in the Fiix-group were within target range vs 29% of INRs in the controls (p=0.06). Also during the initiation period FII was 47% vs. 30% within the 95% stable range established for the PT method (p=0.06), FVII 60% vs. 73% (p=0.13), FIX 41% vs 36% (p=0.69), and FX 51% vs 38% (p=0.20), respectively. The more fluctuating INR in the PT group is also reflected by a rollercoaster like pattern of warfarin dosing as opposed to the more cascade like pattern that is observed in the Fiix group.
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Conclusion: During stable warfarin AC VKD factors are similarly reduced with Fiix-PT or PT monitoring.During initiation of warfarin monitored with the Fiix-PT, FVII decreases initially more than with PT monitoring but subsequently stabilizes and fluctuates less. Fiix-PT leads to smoother reduction in FII and X which stabilize faster than during PT monitoring. The smoother anticoagulant effect is also reflected by the warfarin dose pattern during initiation. The results may suggest that the Quick-PT confounds warfarin management during initiation and dose changes.
Gudmundsdottir:Fiix Diagnostics Ltd: Equity Ownership, I am a co-inventor of the Fiix prothrombin time and have stocks in Fiix Diagnostics, a startup company with the two inventors of the test as majority shareholders. The company is responsible for patent applications in process. Patents & Royalties. Onundarson:Fiix Diagnostics Ltd: Equity Ownership, I am a co-inventor of the Fiix prothrombin time and have stocks in Fiix Diagnostics, a startup company with the two inventors of the test as majority shareholders. The company is responsible for patent applications in process. Patents & Royalties.
Objective. To investigate the association between menstrual flow weight measured from modern sanitary pads (converting liquid to non-evaporating gel) and clinically assessed normal, increased or ...decreased menstrual flow. Design. Objective method development study. Setting. Outpatient clinic, University Hospital, Reykjavik. Population. One hundred and thirteen volunteers included 26 normally menstruating adult women and 52 normally menstruating teenagers not using oral or intrauterine contraception, seven normally menstruating women using oral contraception, 17 women with clinically diagnosed menorrhagia, five women using oral contraception for clinical menorrhagia, and six teenage girls claiming heavy menstrual flow. Methods. Menstruation length, menstrual flow weight and history of iron deficiency were assessed. During the menstruation following recruitment, all women collected their used protective pads in a hygienic manner and returned them to the laboratory for accurate weighing. Main outcome measures. Menstrual flow total weight measured in grams. Results. Mean menstrual flow total weight in the 78 asymptomatic women was 51 g (median 44, range 5-144). The mean flow in 17 women clinically diagnosed with menorrhagia was 217 g (median 207, range 63 - 402) (p<0.0001 compared to healthy women). The seven healthy women using oral contraceptives discharged 13 g (13-19) (p=0.0004 compared with normals). Menstruation lasted<eight days in 77/78 healthy women and in 12 of 17 clinically diagnosed menorrhagic women. Conclusions. Measurement of menstrual flow total weight accurately reflects clinically assessed normal, increased and decreased flow. The method is an easy and accurate way of objectively estimating menstrual flow.
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