ALBERT

Description: Background: Many hospitalized patients with PE die. A large registry study described a mortality rate of 17.4% in patients with PE and suggested 45% of these deaths were due to the PE. Data on death and PE is usually derived retrospectively from hospital databases without chart confirmation and to our knowledge no study has attempted to determine the accuracy of coding for PE deaths. Furthermore, it is unclear how often deaths caused by PE could have been prevented. Methods: A retrospective chart review of PE cases hospitalized at a tertiary care center. Charts over an 8 year period ending in 2004 were reviewed if the hospital database record identified PE as a diagnosis by the ICD-10 coding system. Charts of those who died were independently reviewed by two thrombosis experts with discrepancies resolved by consensus or a third reviewer. Prior to chart review definitions were agreed upon. The coding as PE was considered correct (confirmed PE) if there was supportive imaging, an autopsy, or in the case of death without imaging or autopsy, the clinical scenario was such that PE could have occurred. The degree of certainty that PE contributed to the death was classified as certain (unexplained hypotension, hypoxia, cardiac arrest with no other explanation other than PE and autopsy confirmation or radiographic confirmation), highly probable (same as certain but no autopsy confirmation), probable (criteria for highly probable but another disease could have caused the death). We considered these cases to be death due to PE. Deaths were also classified as possible (other cause suspected based on clinical evidence but 100% certainty not available), or unlikely due to PE (all other cases). In cases defined as death due to PE we determined whether any further intervention could have prevented death. Results: 612 cases were identified of whom 68 had radiographic or autopsy data that ruled out the diagnosis and in 46 the coding was clearly an error. 498 cases of PE were identified, 111 of whom died during hospitalization; the mortality rate in those the hospital coded as PE was 18% vs 22% of those with confirmed PE. Death due to PE was diagnosed in 70 patients (14% of patients with confirmed PE and 11% of all patients coded as PE). In the remaining 41 deaths, PE was possible in 24 and unlikely in 17. Disagreement was uncommon. There was no difference between the likelihood of death from PE in the group diagnosed by imaging and autopsy compared with the group where PE death was confirmed by an appropriate clinical scenario. 38 deaths due to PE may have been prevented with an additional intervention: prophylaxis (55%), earlier diagnosis (45%), inferior vena cava filter (IVCF) (32%), anticoagulation (18%), embolectomy 5%, thrombolytics (3%). The remaining deaths due to PE were not preventable since 15 patients were palliative and did not receive active treatment, 9 died before a diagnosis was made and in 8 another disease prevented treatment. Conclusions: Using hospital database records is a reasonable means to evaluate PE mortality and our death due to PE rates are similar to those in registry publications. Surprisingly imaging and autopsy results do not increase the probability of reaching the conclusion that death is due to PE. Over half of preventable PE deaths may have been prevented by prophylaxis and one third with an IVCF.

Description: Single-nucleotide polymorphisms in genes that affect warfarin metabolism (cytochrome P450 2C9 gene, CYP2C9) and response (vitamin K epoxide reductase complex 1 gene, VKORC1) have an important influence on warfarin therapy, particularly during initiation; however, there is a lack of consensus regarding the optimal pharmacogenetics-based initiation strategy. We conducted a prospective cohort study in which patients requiring warfarin therapy for atrial fibrillation or venous thromboembolism were initiated with a novel pharmacogenetics-initiation protocol (WRAPID, Warfarin Regimen using A Pharmacogenetics-guided Initiation Dosing) that incorporated loading and maintenance doses based on genetics, clinical variables, and response (n = 167, followed up for 90 days), to assess the influence of genetic variations on anticoagulation responses. Application of the WRAPID algorithm resulted in a negligible influence of genetic variation in VKORC1 or CYP2C9 on time to achievement of first therapeutic response (P = .52, P = .28) and risk of overanticoagulation (P = .64, P = .96). After adjustment for covariates, time to stable anticoagulation was not influenced by VKORC1 or CYP2C9 genotype. Importantly, time spent within or above the therapeutic range did not differ among VKORC1 and CYP2C9 genotype groups. Moreover, the overall time course of the anticoagulation response among the genotype groups was similar and predictable. We demonstrate the clinical utility of genetics-guided warfarin initiation with the WRAPID protocol to provide safe and optimal anticoagulation therapy for patients with atrial fibrillation or venous thromboembolism.

Description: Abstract 3125 Poster Board III-62 VTE is the most frequent complication of OS and it can be prevented through anticoagulant prophylaxis. Numerous studies have evaluated different agents for this purpose and there are new agents currently under development or recently approved for this indication. We conducted a systematic review of randomized controlled trials (RCT) evaluating administration of anticoagulants for VTE prophylaxis in OS and performed a MA of proportions to estimate the overall incidence of major VTE (proximal VTE, pulmonary embolism (PE), or death from PE), total VTE (proximal and distal VTE, PE or death from PE), symptomatic VTE and major bleeding episodes (as defined by the International Society on Thrombosis and Hemostasis). We included RCT comparing currently approved anticoagulants (head-to-head or placebo-controlled) for VTE prophylaxis in OS (hip and knee arthroplasty and hip fracture surgery) using systematic evaluation of VTE (ultrasound or venography, pulmonary angiography, CT pulmonary angiography, or ventilation perfusion scan). Heterogeneity of proportions was evaluated using a chi2 test and pooled estimates of proportions were obtained using either a fixed or a random effects model in which the weights were estimated as proposed by Laird and Mosteller. We retrieved 74 studies including180 research arms and enrolling 71,012 patients. The total number of events and evaluable patients, percentage of events and 95% CI, and number of study arms included are shown in the table. We found differences in the percentage of VTE and bleeding events associated with the use of different anticoagulants for VTE prophylaxis after OS. Due to the nature of the analysis no effect measure can be estimated. These estimates might help to design future studies. Major VTE Total VTE Symptomatic VTE Major Bleeding Cases / Evaluable Pts. (N) Percentage (95% CI) Study arms (N) Cases / Evaluable Pts. (N) Percentage (95% CI) Study arms (N) Cases / Evaluable Pts. (N) Percentage (95% CI) Study arms (N) Cases / Evaluable Pts. (N) Percentage (95% CI) Study arms (N) All patients LMWH 993/23692 5.96 (5.81, 6.11) 72 4068/22610 20.29 (20.04, 20.55) 80 193/19431 1.32 (1.27, 1.37) 35 476/28725 1.98 (1.93, 2.02) 70 UFH 234/2407 13.39 (12.86, 13.93) 14 596/2537 22.54 (22, 23.08) 17 11/339 3.24 (3.06, 3.43) 4 70/2849 2.75 (2.61, 2.89) 16 Warfarin 269/5677 6.28 (6.09, 6.46) 12 1317/4203 31.05 (30.44, 31.66) 12 71/4146 1.95 (1.83, 2.08) 6 96/6751 1.78 (1.69, 1.87) 12 Fonda 96/3673 3.81 (3.53, 4.09) 7 223/3477 6.82 (6.57, 7.07) 6 69/6398 1.06 (1.01, 1.1) 8 121/6576 1.63 (1.55, 1.71) 9 Riva 50/5025 2.02 (1.86, 2.19) 8 242/4595 13.05 (12.16, 13.94) 8 29/6252 0.46 (0.45, 0.48) 6 31/6643 0.63 (0.59, 0.68) 8 Dabi 149/4091 3.64 (3.59, 3.69) 6 834/4051 22.96 (21.91, 24.01) 6 26/3664 0.71 (0.67, 0.75) 4 67/5419 1.21 (1.17, 1.26) 6 Placebo 193/710 24.26 (23.17, 25.34) 10 379/816 49.35 (48.08, 50.62) 11 19/198 12.02 (10.32, 13.72) 3 12/753 1.59 (1.5, 1.68) 7 Total 1984/45275 129 7659/42289 140 418/40428 66 873/57716 128 Total Hip Arthroplasty LMWH 653/15978 6 (5.85, 6.16) 50 1817/14480 15.58 (15.35, 15.82) 55 81/11552 0.7 (0.69, 0.72) 19 306/18010 1.97 (1.92, 2.02) 45 UFH 187/1739 14.3 (13.64, 14.96) 11 354/1836 20.13 (19.46, 20.8) 13 11/246 4.47 (4.21, 4.73) 3 52/1451 3.2 (3.01, 3.39) 11 Warfarin 77/2758 4.28 (4.08, 4.48) 6 265/1273 20.82 (20.59, 21.04) 6 32/1833 1.75 (1.69, 1.81) 2 47/2856 2.23 (2.09, 2.37) 5 Fonda 28/1799 2.96 (2.58, 3.33) 3 85/1695 5.01 (4.91, 5.12) 2 15/2255 0.67 (0.63, 0.7) 2 69/2349 2.94 (2.87, 3.01) 3 Riva 25/2938 2.21 (1.95, 2.46) 5 73/2749 9.72 (8.92, 10.53) 5 10/3468 0.29 (0.27, 0.31) 3 14/3795 0.49 (0.44, 0.54) 5 Dabi 72/1803 3.99 (3.88, 4.11) 2 124/1766 7.02 (6.77, 7.27) 2 21/2293 0.92 (0.91, 0.93) 2 38/2309 1.65 (1.58, 1.72) 2 Placebo 105/414 26.01 (24.76, 27.27) 7 174/418 45.43 (43.74, 47.13) 7 4/147 2.72 (2.46, 2.98) 2 3/388 0.77 (0.69, 0.86) 5 Total 1147/27429 84 2892/24217 90 174/21794 33 529/31158 76 Total Knee Arthroplasty LMWH 277/6916 4.45 (4.34, 4.55) 25 2062/7326 30.72 (30.37, 31.07) 32 83/4902 1.69 (1.66, 1.73) 11 89/7808 1.14 (1.12, 1.16) 26 UFH 42/638 6.58 (6.39, 6.78) 3 226/638 35.42 (35.05, 35.79) 3 0/93 NE 1 3/318 0.94 (0.84, 1.05) 2 Warfarin 192/2919 8.1 (7.88, 8.32) 9 1052/2930 39.36 (38.69, 40.02) 9 39/2056 1.9 (1.84, 1.96) 3 28/3407 0.82 (0.79, 0.85) 8 Fonda 23/452 9.3 (7.93, 10.67) 2 45/361 12.47 (12.12, 12.81) 1 3/517 0.58 (0.51, 0.65) 1 12/601 2 (1.88, 2.11) 2 Riva 25/2087 1.2 (1.15, 1.24) 3 169/1846 18.55 (16.47, 20.63) 3 19/2784 0.68 (0.65, 0.71) 3 17/2848 0.6 (0.57, 0.63) 3 Dabi 77/2288 3.37 (3.32, 3.41) 4 710/2285 30.98 (30.42, 31.55) 4 5/1371 0.36 (0.32, 0.41) 2 29/3110 0.93 (0.89, 0.98) 4 Placebo 88/296 27.12 (24.54, 29.7) 4 205/398 55.19 (53.53, 56.84) 5 15/51 29.41 (28.16, 30.66) 1 9/365 2.47 (2.31, 2.62) 4 Total 724/15596 50 4469/15784 57 164/11774 22 187/18457 49 LMWH Low molecular weight heparin, UFH unfractionated heparin, Riva Rivaroxaban, Dabi Dabigatran etexilate Disclosures Lazo-Langner: Boehringer Ingelheim: Honoraria. Rodger:Bayer: Research Funding; Leo Pharma: Research Funding; Pfizer: Research Funding; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Biomerieux: Research Funding; GTC Therapeutics: Research Funding.

Description: AC proph after OS results in a decrease in the incidence of VTE with an associated increase in the risk of major bleeding (MB). Several AC agents and schedules are used; however the optimal timing of initiation has not been determined. It is likely that the proximity to the time of surgery might influence both the efficacy and safety of the AC thus altering their risk-benefit profile. Using a clinical cost-effectiveness approach we compared different AC and timings of VTE proph in patients undergoing OS. A meta-analysis of 55 randomized trials was done to estimate the risk (MB) and benefit (averted VTE) of proph in OS using placebo (plac) or different AC (ximelagatranxim, low molecular weight heparin-LMWH, unfractionated heparin-UFH, warfarin-warf and fondaparinux-fonda) and timings of initiation (defined as preoperative (preop) if the first dose of the AC was administered 〉2 hrs before surgery, perioperative (periop)if between 2 hrs before or up to 12 hrs after the surgery and postoperative (postop) if starting 12 hrs or more after surgery). Means and variances of the MB and VTE estimates were used to parameterize Monte Carlo simulations for a beta distribution using 1,000 replications. Incremental risk, benefit and risk-benefit ratios (compared to placebo) were calculated from the replications. All AC/timing combinations were compared across a range of benefit-risk tradeoff values (risk acceptance) by calculating the percentage of replications with the highest net clinical benefit (NCB; e.g. incremental benefit - incremental risk · tradeoff) for each AC/timing combination. A higher NCB represents a better risk-benefit profile. In addition all anticoagulants were pooled together according to the initial timing of administration and NCB was calculated using random re-sampling of the replications. Analyses were done separately for major VTE (mVTE; proximal deep vein thrombosis (DVT) + pulmonary embolism), and total VTE (tVTE; mVTE + distal DVT) and a sensitivity analysis was done after excluding xim. The reference tradeoff was estimated from the case-fatality rate-ratios of VTE to MB (mVTE/MB=0.39; tVTE/MB=0.10). At the reference tradeoff value, the AC/timing combination with the highest probability of having the best risk-benefit profile was postop xim analyzed by both mVTE and tVTE (99 and 58%, respectively). After excluding xim the AC/timing combination of choice was postop LMWH if analyzed by mVTE (60%) or preop LMWH if analyzed by tVTE (59%). When all AC were pooled those administered postop had the highest probability of having the best risk-benefit profile analyzed by mVTE (48%) and the choice was indifferent between preop (45%) and postop (40%) if analyzed by tVTE. After excluding xim from the pooled analysis the choice was indifferent between preop (40%) and postop (35%) if analyzed by mVTE and if analyzed by tVTE the choice was preop (55%) followed by postop (27%). Our results suggest that: postop administration of AC proph has the best risk-benefit profile; the results are influenced by the event defining benefit (mVTE or tVTE); in some analyses preop administration was best, and; periop administration always had the worst risk-benefit profile. We conclude that periop AC proph after OS should not be used.

Description: Major VTE is the most frequent complication of OS. Current recommendations are to administer prophylaxis with an anticoagulant agent for at least 7–10 days. Numerous studies have evaluated different agents for this purpose. Although the most recent studies are usually methodologically sound, several studies have been hampered by inappropriate designs and insufficient sample sizes. In order to help with the design of future trials we conducted a systematic review of randomized trials evaluating short-term (〈 15 days) administration of anticoagulants for VTE prophylaxis in OS and performed a MA of simple proportions to estimate the overall incidence of major VTE (proximal VTE, pulmonary embolism (PE), or death from PE), total VTE (proximal and distal VTE, PE or death from PE), and major bleeding episodes (as defined by the authors and defined using a definition similar to the one proposed by the International Society on Thrombosis and Haemostasis-ISTH). We included randomized trials comparing different drugs for VTE prophylaxis in OS (hip and knee arthroplasty and hip fracture surgery) using systematic evaluation of VTE (ultrasound or venography, pulmonary angiography, tomographic angiography, or ventilation perfusion lung scan). Heterogeneity of proportions was evaluated using a chi ² test and pooled estimates of proportions were obtained using a fixed or a random effects model as appropriate. In the latter the weights were estimated as proposed by Laird and Mosteller. We retrieved 55 studies (135 research arms) which enrolled 42,131 patients. The percentage and variance of major and total VTE and major bleeding are shown in table 1. The total number of events and the number of evaluable patients are shown in table 2. We found differences in the percentage of clinical outcomes associated with the use of different agents for VTE prophylaxis after OS, however, because of the analytical strategy used no estimation of odds or risk reduction can be derived from this data. We believe that these estimates will be of help for the design of future studies.