Standardized Management Protocol in Severe Postpartum Hemorrhage: A Single-Center Study.

Severe postpartum hemorrhage (sPPH) is an obstetric emergency that needs prompt and effective therapy to reduce the risk of complications. In this study, women who developed sPPH (study cohort, n = 27) were treated according to a standardized management protocol prescribing sequential administration of uterotonic drugs, crystalloids, tranexamic acid, labile blood products, low-dose fibrinogen, and recombinant activated factor VII (rFVIIa). This group was compared to patients treated with different strategies during 2 preceding periods: an in-house guideline regulating the administration of rFVIIa (historical cohort 1, n = 20) and no specific guideline (historical cohort 2, n = 27). The management protocol was used over 33 months. The study cohort had a lower estimated blood loss ( P = .004) and required less red blood cell concentrates ( P = .007), fresh frozen plasma units ( P = .004), and platelet concentrates ( P = .020) compared to historical cohort 1 and historical cohort 2, respectively. The necessity of emergency postpartum hysterectomy was lower in the study group ( P = .012). In conclusion, in patients with sPPH treated with this standardized management protocol, we observed a decreased requirement of labile blood products and lower need to proceed to emergency postpartum hysterectomy.

Impact of rivaroxaban on point-of-care assays.

BACKGROUND: Point-of-care testing (POCT) is regularly used to assess haemostasis in various clinical settings. The impact of rivaroxaban on those POCT is still elusive. We aimed to study the effects of rivaroxaban on most commonly used POCT assays. METHODS: Blood samples were taken before, 3h, and 24h after administration of 20mg rivaroxaban to 20 healthy volunteers as part of a prospective, multicenter validation study (clinicaltrials.govNCT01710267). Blood samples were analysed with thromboelastometry (ROTEM®), two platelet function assays (INNOVANCE® PFA-200 and Multiplate®), and the CoaguChek® XS. Rivaroxaban plasma levels were determined using liquid chromatography-mass spectrometry. RESULTS: Rivaroxaban significantly modified some thromboelastometry parameters (CT INTEM: mean difference 56.1s, 95% CI: 41.8, 70.3; CT EXTEM: 47.5s, 95% CI: 37.8, 57.1; CT HEPTEM: 50.1s, 95% CI: 34.7, 65.6), and CoaguChek® XS parameters (prothrombin time: mean difference 3.8s, 95% CI: 3.3, 4.2; INR: 0.32, 95% CI: 0.27, 0.38; prothrombin ratio: -36.1%, 95% CI: -32.3, -39.9). CT EXTEM and INR showed a moderate correlation with rivaroxaban plasma levels (r=0.83; 95% CI 0.69, 0.9 and r=0.83; 95% CI 0.70, 0.91, respectively) and a high sensitivity to detect rivaroxaban treatment at peak levels (0.95; 95% CI: 0.76, 1.0 and 0.90, 95% CI 0.70, 0.99, respectively). CONCLUSIONS: Rivaroxaban 20mg treatment significantly alters ROTEM® and CoaguChek® XS parameters. Even though POCT do not allow precise quantification of rivaroxaban plasma concentration, CT EXTEM and CoaguChek XS detect the presence of rivaroxaban at peak level with a high sensitivity.

Full-length nucleotide sequences of 30 common SLC44A2 alleles encoding human neutrophil antigen-3.

BACKGROUND: Human neutrophil antigen-3a (HNA-3a) alloantibodies can cause severe transfusion-related acute lung injury. The frequencies of the single-nucleotide polymorphisms (SNPs) indicative of the two clinically relevant HNA-3a/b antigens are known in many populations. In this study, we determined the full-length nucleotide sequence of common SLC44A2 alleles encoding the choline transporter-like protein-2 that harbors HNA-3a/b antigens. STUDY DESIGN AND METHODS: A method was devised to determine the full-length coding sequence (CDS) and adjacent intron sequences from genomic DNA by eight polymerase chain reaction amplifications covering all 22 SLC44A2 exons. Samples from 200 African American, 96 Caucasian, two Hispanic, and four Asian blood donors were analyzed. We developed a decision tree to determine alleles (confirmed haplotypes) from the genotype data. RESULTS: A total of 10 SNPs were detected in the SLC44A2 CDS. The noncoding sequences harbored an additional 28 SNPs (one in the 5'-untranslated region [UTR]; 23 in the introns; and four in the 3'-UTR). No SNP indicative of a nonfunctional allele was detected. The nucleotide sequences for 30 SLC44A2 alleles (haplotypes) were confirmed. There may be 66 haplotypes among the 604 chromosomes screened. CONCLUSIONS: We found 38 SNPs, including one novel SNP, in 8192 nucleotides covering the CDS of the SLC44A2 gene among 302 blood donors. Population frequencies of these SNPs were established for African Americans and Caucasians. Because alleles encoding HNA-3b are more common than non-functional SLC44A2 alleles, we confirmed our previous postulate that African American donors are less likely to form HNA-3a antibodies compared to Caucasians.

Reference values for oral iron absorption of bivalent iron in healthy volunteers.

BACKROUND: It is a challenge to establish the cause of iron deficiency in the absence of obvious reasons. There has been no prospectively validated oral iron absorption test (OIAT) that could confidently confirm or exclude iron malabsorption. The aim, therefore, was the establishment of an OIAT with defining reference values of plasma iron in healthy volunteers. METHODS: We included 49 healthy volunteers who received 200 mg of bivalent ferrous fumarate in fasting condition and measured plasma iron after 2 and 4 hours as well as after 3 and 5 days. After a wash-out phase, 23 healthy volunteers proceeded to receive trivalent iron hydroxide polymaltose in fasting condition, and 11 participants were tested without iron. RESULTS: Reference values of absolute and relative plasma iron after oral iron ingestion could be established. There was a significant increase of plasma iron after bivalent iron intake within 4 hours after ingestion (absolute increase after 4h: from initially 17 ± 4 µmol/l to 35 ± 12 µmol/l in females and from 21 ± 7 µmol/l to 33 ± 11 µmol/l in males, relative plasma iron concentration (defined reference: 1.0) after 4 h: 2.1 ± 0.7 in females and 1.7 ± 0.6 in males). There was no relevant increase with trivalent iron nor without iron. Relative iron increase correlates to iron storage. In general, females had lower ferritin levels and thus higher increases of plasma iron. CONCLUSION: An OIAT in healthy volunteers could be established. Its prospective validation using bivalent iron in iron deficiency is desirable.

A Simple Guideline Reduces the Need for Red Blood Cell Transfusions in Swiss Hospitals: A Prospective, Multicentre, Before-and-After Study in Elective Hip and Knee Replacement.

INTRODUCTION: Optimising the use of blood has become a core task of transfusion medicine. Because no general guidelines are available in Switzerland, we analysed the effects of the introduction of a guideline on red blood cell (RBC) transfusion for elective orthopaedic surgery. METHODS: Prospective, multicentre, before-and-after study comparing the use of RBCs in adult elective hip or knee replacement before and after the implementation of a guideline in 10 Swiss hospitals, developed together with all participants. RESULTS: We included 2,134 patients, 1,238 in 7 months before, 896 in 6 months after intervention. 57 (34 or 2.7% before, 23 or 2.6% after) were lost before follow-up visit. The mean number of transfused RBC units decreased from 0.5 to 0.4 per patient (0.1, 95% CI 0.08-0.2; p = 0.014), the proportion of transfused patients from 20.9% to 16.9% (4%, 95% C.I. 0.7-7.4%; p = 0.02), and the pre-transfusion haemoglobin from 82.6 to 78.2 g/l (4.4 g/l, 95% C. I. 2.15-6.62 g/l, p < 0.001). We did not observe any statistically significant changes in in-hospital mortality (0.4% vs. 0%) and morbidity (4.1% vs. 4.0%), median hospital length of stay (9 vs. 9 days), follow-up mortality (0.4% vs. 0.2%) and follow-up morbidity (6.9% vs. 6.0%). CONCLUSIONS: The introduction of a simple transfusion guideline reduces and standardises the use of RBCs by decreasing the haemoglobin transfusion trigger, without negative effects on the patient outcome. Local support, training, and monitoring of the effects are requirements for programmes optimising the use of blood.

Patient self-management of oral anticoagulation with vitamin K antagonists in everyday practice: efficacy and safety in a nationwide long-term prospective cohort study.

Patient self-management (PSM) of oral anticoagulation is under discussion, because evidence from real-life settings is missing. Using data from a nationwide, prospective cohort study in Switzerland, we assessed overall long-term efficacy and safety of PSM and examined subgroups. Data of 1140 patients (5818.9 patient-years) were analysed and no patient were lost to follow-up. Median follow-up was 4.3 years (range 0.2-12.8 years). Median age at the time of training was 54.2 years (range 18.2-85.2) and 34.6% were women. All-cause mortality was 1.4 per 100 patient-years (95% CI 1.1-1.7) with a higher rate in patients with atrial fibrillation (2.5; 1.6-3.7; p<0.001), patients>50 years of age (2.0; 1.6-2.6; p<0.001), and men (1.6; 1.2-2.1; p = 0.036). The rate of thromboembolic events was 0.4 (0.2-0.6) and independent from indications, sex and age. Major bleeding were observed in 1.1 (0.9-1.5) per 100 patient-years. Efficacy was comparable to standard care and new oral anticoagulants in a network meta-analysis. PSM of properly trained patients is effective and safe in a long-term real-life setting and robust across clinical subgroups. Adoption in various clinical settings, including those with limited access to medical care or rural areas is warranted.

DARC alleles and Duffy phenotypes in African Americans.

BACKGROUND: The DARC (Duffy blood group, chemokine receptor) gene encodes for a transmembrane glycoprotein that functions as a chemokine transporter, is a receptor for Plasmodium vivax and P. knowlesi, and expresses the Duffy blood group antigens (Fy). The Fy(a-b-) phenotype found in people of African descent is typically associated with a -67t>c mutation in the 5'-untranslated region (UTR), which prevents red blood cells being invaded by P. vivax and P. knowlesi. The aim of this study was to establish DARC allele frequencies in an African American blood donor cohort, determine a phylogenetic tree for DARC, and compare human and Neandertal DARC genes. STUDY DESIGN AND METHODS: The DARC nucleotide sequence of 54 African American blood donors was determined from genomic DNA. Heterozygous substitutions were resolved by sequencing of haplotype-specific amplifications. A phylogenetic tree for DARC was established using the neighbor-joining method with Pan troglodytes as root. RESULTS: A total of 108 haplotypes of the DARC gene could be unambiguously determined from nucleotide position -300 in the 5' UTR to +300 in the 3' UTR. Eleven different alleles were found, including the clinically relevant FY*A, FY*B, FY*B-67C, FY*B298A, and FY*X alleles. All phenotype predictions based on genotypes matched the serologically determined phenotypes exactly: 52% Fy(a-b-), 28% Fy(a-b+), and 20% Fy(a+b-). CONCLUSIONS: The nucleotide sequencing approach using one amplicon is a practical genotyping method for DARC and allows the determination of haplotypes even in heterozygous constellations. We developed a phylogenetic tree for DARC alleles and postulated a distinct FY*B allele as ancestral for the extant DARC alleles in humans.

Frequencies of SLC44A2 alleles encoding human neutrophil antigen-3 variants in the African American population.

BACKGROUND: The human neutrophil antigen-3 (HNA-3) epitopes reside on the choline transporter-like protein-2 (CTL2). A single-nucleotide substitution (461G>A; Arg154Gln) on the CTL2 gene (SLC44A2) defines the allele SLC44A2*1, which expresses HNA-3a, and SLC44A2*2, which expresses HNA-3b; an additional substitution (457C>T; Leu153Phe) in SLC44A2*1:2 may impact genotyping systems. People who only express HNA-3b may develop anti-HNA-3a. These alloantibodies have been linked to severe transfusion-related acute lung injury, which may be a reason to screen blood donors for SLC44A2*2 homozygosity. For Caucasian and Asian populations, SLC44A2 allele frequencies are known. Our primary objective was to determine the SLC44A2 allele frequencies in the African American population. STUDY DESIGN AND METHODS: Purified DNA from 334 individuals (202 male, 132 female; 241 African American, 93 Caucasian) was collected. Two real-time polymerase chain reaction assays were developed to genotype all samples; results were confirmed by nucleotide sequencing. RESULTS: In 241 African American donors, the allele frequency of SLC44A2*1 was 93% (85%-<100%; 95% confidence intervals, Poisson distribution) while SLC44A2*2 was 7% (5%-10%). In 93 Caucasian donors, the allele frequency of SLC44A2*1 was 83% (71%-98%) and SLC44A2*2 was 17% (11%-24%), matching previously reported data for Caucasians but differing from African Americans (p < 0.001, Fisher's exact test). CONCLUSIONS: This study describes the allele frequencies of the three known HNA-3 variants in an African American population. We found that African Americans have a significantly lower probability of possessing the SLC44A2*2 allele and may thus be less likely to form the clinically relevant anti-HNA-3a.

Low-dose recombinant factor VIIa for massive bleeding: a single centre observational cohort study with 73 patients.

QUESTIONS UNDER STUDY: recombinant activated factor VII (rFVIIa) is used off-label for massive bleeding. There is no convincing evidence of the benefits of this practice and the minimal effective dose is unknown. The aim of the study was to evaluate our in-house guideline recommending a low dose of 60 µg/kg for off-label use of rFVIIa. METHODS: observational cohort study at the Inselspital Bern, a tertiary care University Hospital in Switzerland. All patients with massive bleeding treated off-label with rFVIIa between January 2005 and December 2007 were included. Survival, change of bleeding and transfusion rates, coagulation parameters and complications were analysed. RESULTS: seventy-three patients received rFVIIa. Severe haemorrhage was documented by a bleeding rate of 1000 mL/h (median; interquartile range 350-3000) and total volume replacement of 11.9 L (6.6-15.2) before administration of rFVIIa. The median rFVIIa-dose was 64 µg/kg (56-71). rFVIIa was administered once in 79% patients, twice in 18%. The bleeding rate was reduced in 82% of the patients. Transfused packed red blood cells decreased from 14 units (8-22) over 4.9 h (2.5-8.8) before rFVIIa to 2 (0-6) in 24 h thereafter, platelet concentrates from 2 units (1-3) to 1 (0-2) and FFP from 11 units (6-16) to 2 (0-9). In-hospital mortality was 14% within 24 h and 32% at day 30. There were two arterial thromboembolic complications possibly related to rFVIIa. CONCLUSION: a single injection of 60 µg/kg rFVIIa, a lower dose than usually recommended, appears to be efficacious in controlling massive bleeding with a very low complication rate.

Red blood cell preservation by droplet freezing with polyvinylpyrrolidone or sucrose-dextrose and by bulk freezing with glycerol.

BACKGROUND: Red blood cell (RBC) preservation is essential to transfusion medicine. Many blood group reference laboratories need a method to preserve rare blood samples for serologic testing at a later date. This study offers a comparison of three common cryoprotective agents and protocols used today: bulk preservation with glycerol and droplet freezing with sucrose-dextrose (S+D) or polyvinylpyrrolidone (PVP). STUDY DESIGN AND METHODS: Human blood from 14 volunteers was collected and frozen at set intervals over 2 weeks with PVP, S+D, or glycerol. The frozen RBCs were later thawed and the percentage of surviving RBCs was determined. Detailed protocols and an instructional video are supplied. RESULTS: Over a 2-week period, RBCs preserved with glycerol and thawed with a widely used protocol showed a recovery of 41 ± 16% (mean ± standard deviation) while those thawed with a modified glycerol protocol showed a recovery of 76 ± 8%. RBCs preserved by droplet freezing with S+D showed a recovery of 56 ± 11% while those preserved by droplet freezing with PVP showed a recovery of 85 ± 6%. Recovery values were similar with ethylenediaminetetraacetic acid or heparin anticoagulants, differing freezing rates, and varying droplet volumes. CONCLUSION: Droplet freezing with PVP offered the greatest recovery. While bulk freezing with glycerol can also be effective, droplet freezing may be a more convenient method overall. It requires less effort to thaw, needs much less storage room, and allows blood group laboratories to be frugal with thawing rare samples.

Codon usage in vertebrates is associated with a low risk of acquiring nonsense mutations.

BACKGROUND: Codon usage in genomes is biased towards specific subsets of codons. Codon usage bias affects translational speed and accuracy, and it is associated with the tRNA levels and the GC content of the genome. Spontaneous mutations drive genomes to a low GC content. Active cellular processes are needed to maintain a high GC content, which influences the codon usage of a species. Loss-of-function mutations, such as nonsense mutations, are the molecular basis of many recessive alleles, which can greatly affect the genome of an organism and are the cause of many genetic diseases in humans. METHODS: We developed an event based model to calculate the risk of acquiring nonsense mutations in coding sequences. Complete coding sequences and genomes of 40 eukaryotes were analyzed for GC and CpG content, codon usage, and the associated risk of acquiring nonsense mutations. We included one species per genus for all eukaryotes with available reference sequence. RESULTS: We discovered that the codon usage bias detected in genomes of high GC content decreases the risk of acquiring nonsense mutations (Pearson's r = -0.95; P < 0.0001). In the genomes of all examined vertebrates, including humans, this risk was lower than expected (0.93 ± 0.02; mean ± SD) and lower than the risk in genomes of non-vertebrates (1.02 ± 0.13; P = 0.019). CONCLUSIONS: While the maintenance of a high GC content is energetically costly, it is associated with a codon usage bias harboring a low risk of acquiring nonsense mutations. The reduced exposure to this risk may contribute to the fitness of vertebrates.

Recruitment of platelets, white blood cells, and hematopoietic progenitor cells during high-yield plateletpheresis.

BACKGROUND: Previous observations suggested recruitment of platelets (PLTs) and white blood cells (WBCs) during plateletpheresis and recruitment of hematopoietic progenitor cells (HPCs) by HPC apheresis. Quantification of recruitment helps to optimize yields and safety of these procedures; detection of WBC or HPC recruitment during plateletpheresis may further elucidate the mechanisms. STUDY DESIGN AND METHODS: This study was a prospective cohort study with 68 single-needle plateletpheresis donations (23 double, PLT yield ≥4.8 × 10(11) ; 23 triple, ≥7.2 × 10(11) ; 22 quadruple, ≥9.6 × 10(11) ). We measured PLTs, WBCs, WBC subpopulations, and circulating HPCs (CD34 mRNA) before, during, and after apheresis; calculated PLT recruitment and ratio of recruited to yielded PLT; and propose a novel concept to optimize the prediction of the PLT counts after apheresis (PLT(post) ). RESULTS: PLT recruitment (mean ± SD, 1.56 ± 0.31) caused a higher PLT(post) than predicted by the instrument (164 × 10(9) ± 23 × 10(9) vs. 111 × 10(9) ± 31 × 10(9) /L; p < 0.0001) in all three groups. The ratio of recruited to yielded PLT was 0.36 ± 0.15. The WBC count decreased by 9% to the time before rinse-back and returned to the baseline thereafter. No changes in circulating HPCs occurred. CONCLUSIONS: PLT recruitment during high-yield plateletpheresis facilitates the harvest of multiple PLT units in a single donation. The use of the ratio of recruited to yielded PLT may optimize the algorithm to predict PLT(post) . There was no recruitment of WBCs and HPCs during plateletpheresis. Therefore, the previously observed recruitment of HPCs during HPC apheresis seems to be related to other factors than the apheresis procedure itself.

Low-molecular-weight heparin in patients with renal insufficiency.

BACKGROUND: Low-molecular-weight heparins (LMWH) have been shown to be safer, more effective and more convenient than unfractionated heparin (UFH) in many clinical situations. However, their use is limited in patients with renal insufficiency (RI) due to bioaccumulation. METHOD: The literature is critically reviewed and known pharmacokinetic properties are summarised. An approach to using LMWH in patients with RI is proposed on the basis of currently available evidence. RESULTS AND DISCUSSION: Pharmacokinetic data of commonly used LMWH and of UFH are summarised in respect of RI. Most data are known on enoxaparin. A dose reduction is recommended in patients with severe RI. Limited data on dalteparin and tinzaparin suggest that there is less bioaccumulation. However, further studies are needed, in respect of long-term use and clinical end-points in particular.There are no data on certoparin and only very limited data on nadroparin. A detailed approach is suggested for the use of LMWH in patients with severe RI. Briefly: (1) before using LMWH, evaluate the patient's renal function, ist expected course, imminent interventions, and general bleeding risk; (2) prefer LMWH to UFH in view of better efficacy and lower bleeding risk in general; (3) however, prefer i.v. UFH to s.c. LMWH if a patient is unstable, is awaiting emergency interventions, or has a high bleeding risk, since UFH can be stopped more quickly due to i.v. administration, has a shorter half-life time, and can be effectively antagonised; (4) prefer a well documented LMWH; use established dosing schemes; (5) monitor LMWH with peak anti-Xa levels in patients with severe RI regularly, and adjust dose to be in target range; (6) do not use LMWH in patients with severe RI if there is no possibility of measuring anti-Xa levels. CONCLUSIONS: LMWH may be considered for patients with severe RI. However, experience, judicious choice and careful monitoring of patients with severe RI treated with LMWH are necessary.

Patient self-management of long-term oral anticoagulation in Switzerland.

Indications for oral anticoagulation (OAC) have increased in recent years. OAC requires frequent monitoring of the prothrombin time to keep the intensity within the therapeutic range and to minimise the risk for complications. Patient self-management (PSM) has been found to improve the quality of OAC. The present study aimed to investigate the first 330 patients performing PSM in Switzerland. A questionnaire was sent to all patients who followed a teaching program for PSM of OAC between 1998 and 2003. Moreover, family physicians were contacted and/or discharge letters were obtained from the hospitals or the treating physicians. During the study period 13 patients died. Out of the 300 patients providing information 254 (85%) still perform PSM. At least one INR determination per two weeks was done by 74% of the patients and 25% performed at least one INR measurement every 15-30 days. The median time spent within the individual INR target range was 72%. No thromboembolic complications occurred, however, among the 13 patients who died, 1 had myocardial infarction and 6 died of heart failure. When counting these events as arterial thromboembolic complications the frequency was 0.6 (95% CI: 0.3-1.3) per 100 patient-years. The frequency of major bleeding was 0.6 (95% CI: 0.2-1.3) per 100 patient-years. We conclude from this study investigating a real-world patient collective that PSM is suitable and safe for the patients identified by their family physicians and successfully trained by our training centre.