Genetic diversity fuels gene discovery for tobacco and alcohol use.

Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury1-4. These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries5. Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.

Role of individual factor X concentrate pharmacokinetic studies in perioperative management of AL amyloidosis-associated acquired factor X deficiency.

BACKGROUND: AL amyloidosis is associated with acquired factor X (FX) deficiency. Experience related to its management is limited to case reports and series using prothrombin complex concentrate, fresh frozen plasma, plasma exchange, recombinant activated factor seven, and desmopressin with limited and variable efficacy. FX concentrate has not been widely used in its management. STUDY DESIGN AND METHODS: We report our experience with the perioperative use of FX concentrate (Coagadex) in two patients with AL amyloidosis-associated acquired FX deficiency requiring surgery, using their individual pharmacokinetic studies to manage perioperative hemostasis. Pharmacokinetic studies involved obtaining post-infusion FX activity at 10 min, 2, and 4 h following the administration of FX concentrate to calculate the FX half-life. RESULTS: Both patients' plasma FX activity was successfully increased to provide perioperative hemostatic support. Monitoring FX activity post-surgery was also utilized to maintain FX activity levels to prevent post-operative bleeding. CONCLUSION: Pharmacokinetic studies have a useful role in tailoring preoperative FX repletion in patients with AL amyloidosis associated with acquired FX deficiency.

Incidental pulmonary embolism in cancer and noncancer patients: Prospective cohort study.

BACKGROUND: Clinical picture and outcome of incidental pulmonary embolism (iPE) compared to symptomatic pulmonary embolism (sPE) remain unclear. METHODS: Demographics, recurrent venous thromboembolism (VTE), mortality, major bleeding, and clinically relevant nonmajor bleeding (CRNMB) were compared between iPE and sPE patients who were followed prospectively at Mayo Thrombophilia Clinic (March 1, 2013 to August 1, 2020). RESULTS: Out of 3576 VTE patients, 1417 (39.6%) had PE: 562 (39.7%) iPE and 855 sPE. Patients with cancer were more likely to have iPE (400 iPE vs. 314 sPE) compared to those without cancer (162 iPE vs. 541 sPE). VTE recurrence rate (all per 100 person-years) was similar in all iPE and sPE patients (3.34 vs. 3.68, p = .50), with cancer (4.16 vs. 4.89, p = .370), and without cancer patients (0.89 vs. 2.80, p = .25). Higher mortality observed in all patients with iPE compared to sPE (46.45 vs. 23.47, p < .001) and with cancer (56.41 vs. 45.77, p = .03) became not significant after adjustment for age, antiplatelet therapy, metastases, and cancer location. Noncancer iPE patients had higher mortality (15.95 vs. 7.18, p = .006) even after adjustment (p = .05). The major bleeding rate was also higher in all patients iPE compared to sPE (7.10 vs. 3.68, p = .03), but not after adjustment (p = .974); higher major bleeding rate in noncancer patients (6.49 vs. 1.25, p = .007) remained significant after adjustment (.02). CRNMB rate was similar to iPE and sPE patients. CONCLUSION: iPE represents a more serious clinical condition compared to sPE as indicated by the higher mortality and major bleeding but these differences reflect underlying comorbidities rather than the seriousness of the embolic event.

Persistence of Ad26.COV2.S-associated vaccine-induced immune thrombotic thrombocytopenia (VITT) and specific detection of VITT antibodies.

Rare cases of COVID-19 vaccinated individuals develop anti-platelet factor 4 (PF4) antibodies that cause thrombocytopenia and thrombotic complications, a syndrome referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT). Currently, information on the characteristics and persistence of anti-PF4 antibodies that cause VITT after Ad26.COV2.S vaccination is limited, and available diagnostic assays fail to differentiate Ad26.COV2.S and ChAdOx1 nCoV-19-associated VITT from similar clinical disorders, namely heparin-induced thrombocytopenia (HIT) and spontaneous HIT. Here we demonstrate that while Ad26.COV2.S-associated VITT patients are uniformly strongly positive in PF4-polyanion enzyme-linked immunosorbent assays (ELISAs); they are frequently negative in the serotonin release assay (SRA). The PF4-dependent p-selectin expression assay (PEA) that uses platelets treated with PF4 rather than heparin consistently diagnosed Ad26.COV2.S-associated VITT. Most Ad26.COV2.S-associated VITT antibodies persisted for >5 months in PF4-polyanion ELISAs, while the PEA became negative earlier. Two patients had otherwise unexplained mild persistent thrombocytopenia (140-150 x 103 /µL) 6 months after acute presentation. From an epidemiological perspective, differentiating VITT from spontaneous HIT, another entity that develops in the absence of proximate heparin exposure, and HIT is important, but currently available PF4-polyanion ELISAs and functional assay are non-specific and detect all three conditions. Here, we report that a novel un-complexed PF4 ELISA specifically differentiates VITT, secondary to both Ad26.COV2.S and ChAdOx1 nCoV-19, from both spontaneous HIT, HIT and commonly-encountered HIT-suspected patients who are PF4/polyanion ELISA-positive but negative in functional assays. In summary, Ad26.COV2.S-associated VITT antibodies are persistent, and the un-complexed PF4 ELISA appears to be both sensitive and specific for VITT diagnosis.

Management Practices for Asparaginase-associated Coagulopathy: A Survey of Pediatric Oncologists.

BACKGROUND: Coagulopathy and thrombosis are well-described complications of asparaginase therapy. However, treatment practices in pediatric hematology/oncology (PHO) patients vary widely as evidence-based guidelines for clinical management of these complications in this population are lacking. OBJECTIVE: The objective of this study was to assess management practices of asparaginase-related coagulopathy by pediatric hematologist/oncologist attending physicians. DESIGN/METHOD: Email survey sent to 2327 PHO physicians primarily practicing in the United States. RESULTS: Two hundred eighty-five (12.2%) attending physicians completed the survey. Only 4.6% (n=13/285) routinely prescribe prophylactic anticoagulation during induction chemotherapy for leukemia. Slightly more than half (n=145/250, 50.9%) of all providers perform baseline coagulation studies. Most providers that were surveyed (n=185/285, 64.9%) only replete coagulant factors if the patient experiences bleeding or bruising. One hundred thirty (n=130/285, 45.6%) physicians replace low fibrinogen. The median fibrinogen replacement was 100 mg/dL (range: 40 to 200 mg/dL) with the median target of at least 100 mg/dL (range: 50 to 200 mg/dL). A minority of physicians (n=39/250, 13.7%) replace low antithrombin. The median antithrombin cutoff activity level was 60% (range: 40% to 100%) with a median target of 75% (range: 40% to 125%). CONCLUSIONS: There is a significant variation in PHO physician practices for monitoring and management of asparaginase-associated hemostatic derangements. Evidence-based guidelines have the potential to standardize practices.

Hemostatic prophylaxis and colonoscopy outcomes for patients with bleeding disorders: A retrospective cohort study and review of the literature.

INTRODUCTION: Hemostatic prophylaxis (HP) is recommended for patients with bleeding disorders (PWBD) before invasive procedures. However, evidence-based guidelines are needed to determine optimal HP strategies. AIM: To determine outcomes of HP for PWBD undergoing colonoscopy. METHODS: We undertook a retrospective cohort study of HP and outcomes of colonoscopy procedures performed between 9 November 1993 and 13 February 2018 for PWBD who received care in the Mayo Clinic Comprehensive Hemophilia Treatment Center. RESULTS: During the study period, 73 PWBD (58 with milder phenotypes: haemophilia, von Willebrand disease [subtypes 1 and 2; II, VII and XI deficiency]) underwent 141 procedures. Preprocedural HP was given to 61%, and interventions were performed in 47%. Of the 39% without preprocedural HP, postprocedural HP was given for 11%. One major (0.7%; 6 days postprocedure despite HP) and 10 minor (7%) bleeding complications occurred, which tended to be in patients with severe disease and/or after excision of larger polyps. There was no significant difference in the rate of bleeding complications with or without preprocedural HP (8.1% vs 5.5%, respectively; P = .74, Fisher's exact test). CONCLUSION: The low bleeding rates in our cohort suggest that preprocedure HP may be withheld for patients with mild bleeding disorders who undergo colonoscopy with a low likelihood of requiring an intervention or who require only low-risk intervention. This strategy may be best used in experienced centres, provided optimal local hemostasis measures are undertaken and postprocedural HP is rapidly available if high-risk intervention is required. Further studies are needed to determine optimal evidence-based HP strategies for PWBD undergoing colonoscopy.

Effect of a near-universal hospitalization-based prophylaxis regimen on annual number of venous thromboembolism events in the US.

The annual number of US venous thromboembolism (VTE) events, the number of potentially preventable events, and the effect of hospitalization-based prophylaxis are uncertain. We estimated VTE attack (incident plus recurrent VTE) rates and the total annual number of US VTE events related and unrelated to hospitalization using Rochester Epidemiology Project resources to identify all Olmsted County, Minnesota, residents with incident or recurrent VTE over the 6-year period 2005-2010. The average annual VTE attack rates related and unrelated to hospitalization were 282 and 8 per 10 000 person-years, respectively. The estimated average number of US VTE events was 495 669 per year (48% unrelated to hospitalization). Among Olmsted County residents hospitalized at a Mayo Clinic hospital from 2005 to 2010, the proportion of patients receiving VTE prophylaxis or with an indication that prophylaxis was unnecessary increased from ∼40% in 2005 to ∼90% by 2010. The annual age- and sex-adjusted hospitalization-related (in-hospital) VTE attack rates from 2005 to 2010 ranged from 251 to 306 (1155 to 1751) per 10 000 person-years (bed-years) and did not change significantly. The median durations of hospitalization and in-hospital prophylaxis were 3 days and 70 hours, respectively. A total of 75% of VTE events occurred after hospital discharge, with a 19.5-day median time to VTE. Additional efforts are needed to identify the individual inpatient and outpatient at high risk for incident and recurrent VTE and target (longer duration) primary and secondary prophylaxis to high-risk individuals who would benefit most.

Sex-based disparities in venous thromboembolism outcomes: A National Inpatient Sample (NIS)-based analysis.

Venous thromboembolism (VTE) contributes to significant morbidity, mortality, and socioeconomic burden. There is a paucity of literature regarding sex-based sociodemographic differences in VTE presentation and short-term outcomes. We aimed to compare clinical outcomes between men and women hospitalized for VTE management. We performed a retrospective analysis using data from the National Inpatient Sample (NIS) database from 2012 to 2013. Inclusion criteria were age 18 years and older and a primary discharge diagnosis of VTE. Sociodemographic features and medical comorbidities were analyzed, as were hospital length of stay and in-hospital mortality rates. A total of 107,896 patients met the inclusion criteria; 53% were female. Median age was 65 years (interquartile range 51-77) and women were older than men (65 vs 62 years, p<0.001). There were significant differences between men and women with respect to race, primary insurance payer and medical comorbidities, and small differences with respect to VTE location. Female sex was associated with a small but significantly longer hospital length of stay (mean ratio 1.04, 95% CI 1.03-1.05, p<0.001) but no significant difference in in-hospital mortality (2.2% vs 2.1%, p=0.15). In a multivariate model, there was no significant difference between women and men with respect to hospital length of stay or in-hospital mortality. In conclusion, we used data from the NIS to study over 100,000 patients hospitalized for VTE, and identified several sex-based disparities in sociodemographic factors and location of VTE. However, in a multivariable analysis correcting for these factors, sex was not associated with significant differences in clinical outcomes.

Therapeutic plasma exchange for perioperative management of patients with congenital factor XI deficiency.

BACKGROUND: Factor XI (FXI) deficiency (hemophilia C [HEM-C]) is a bleeding disorder with unpredictable severity that correlates poorly with FXI coagulation activity (FXI:C). It poses a perioperative hemostatic management challenge. For US patients with severe disease, fresh frozen plasma (FFP) or, in current use, thawed plasma is the most readily available option but comes with risk of volume overload. We report our experience of using therapeutic plasma exchange (TPE) as an alternative perioperative management strategy. METHODS: A retrospective review of all HEM-C patients who underwent surgical procedures. Data were collected, including demographics, bleeding history, surgical site, perioperative hemostatic intervention, and outcome. RESULTS: Between July 1997 and September 2014, 28 HEM-C patients (12 men) were identified, 4 with severe disease (FXI:C <2% or excessive bleeding). Nineteen patients underwent 91 invasive procedures. For nearly 60% of the procedures, no periprocedural hemostatic intervention was provided; before 4 procedures (3 patients), 1 plasma volume TPE preoperatively with FFP was administered. Patient 1, a 28-year-old woman (FXI:C, 35%) with a history of excessive surgical bleeding, underwent 2 TPE procedures before laparoscopic pelvic biopsy and subsequent abdominal hysterectomy with salpingo-oophorectomy that increased her FXI:C to 48%. Patient 2, a 79-year-old man (FXI:C, <2%), had TPE before total hip arthroplasty, increasing his FXI:C to 24%. Patient 3, a 59-year-old man (FXI:C, <2%), had TPE before prostate laser enucleation, increasing his FXI:C to 46%. Patients 1 and 3 had mild reactions during TPE; no patient had evidence of volume overload. All patients had adequate intraoperative surgical hemostatic outcomes. CONCLUSION: TPE is an effective alternative presurgical hemostatic intervention in HEM-C with potentially lower risk of circulatory volume overload.

Predictors of venous thromboembolism recurrence and bleeding among active cancer patients: a population-based cohort study.

Active cancer is the major predictor of venous thromboembolism (VTE) recurrence, but further stratification of recurrence risk is uncertain. In a population-based cohort study of all Olmsted County, Minnesota, residents with active cancer-related incident VTE during the 35-year period from 1966 to 2000 who survived 1 day or longer, we estimated VTE recurrence, bleeding on anticoagulant therapy, and survival and tested cancer and noncancer characteristics and secondary prophylaxis as predictors of VTE recurrence and bleeding, using Cox proportional hazards modeling. Of 477 patients, 139 developed recurrent VTE over the course of 1533 person-years of follow-up. The adjusted 10-year cumulative VTE recurrence rate was 28.6%. The adjusted 90-day cumulative incidence of major bleeding on anticoagulation was 1.9%. Survival was significantly worse for patients with cancer who had recurrent VTE (particularly pulmonary embolism) and with bleeding on anticoagulation. In a multivariable model, brain, lung, and ovarian cancer; myeloproliferative or myelodysplastic disorders; stage IV pancreatic cancer; other stage IV cancer; cancer stage progression; and leg paresis were associated with an increased hazard, and warfarin therapy was associated with a reduced hazard, of recurrent VTE. Recurrence rates were significantly higher for cancer patients with 1 or more vs no predictors of recurrence, suggesting these predictors may be useful for stratifying recurrence risk.

From vitamin K antagonists to liver international normalized ratio: a historical journey and critical perspective.

Adoption of international normalized ratio (INR) to harmonize prothrombin time has greatly improved the safety and effectiveness of vitamin K antagonists (VKA) oral anticoagulant therapy. INR is also a major laboratory variable in calculating the widely used Model for End-Stage Liver Disease (MELD) score for liver transplant organ prioritization. However, since the conventional INR (INRVKA) is calibrated specifically for VKA patients, its interlaboratory variation has a significant impact on the accuracy of MELD score. Though still requiring further clinical validation in large numbers of waitlisted patients, the alternative liver INR calibrated by using plasma from liver disease patients instead of VKA patients may harmonize the differences and thus more suitable for MELD score calculation. The objective of this article is to review the history of INR, MELD score, and liver INR, and discuss the challenges and solutions of liver INR implementation.

Effect of residual platelets in frozen-thawed plasma on results of dilute Russell's viper venom time assay for lupus anticoagulant testing.

OBJECTIVES: To determine the impact of residual platelets on dilute Russell's viper venom time (DRVVT) assay in frozen-thawed plasma submitted for lupus anticoagulant (LAC) testing. METHODS: We measured platelet counts in frozen-thawed samples submitted for LAC testing and evaluated the association between platelet count and the DRVVT screening time and ratios. We also spiked platelets into a LAC-positive sample to observe the effect on the DRVVT. RESULTS: Progressive increase in platelet count resulted in a statistically significant shortening of the DRVVT assay results on plasma after 1 freeze-thaw cycle. A similar effect was noted on the LAC-positive sample. CONCLUSIONS: Residual platelets in plasma samples result in shortening of DRVVT assay after 1 freeze-thaw cycle. This may result in a false-negative LAC test result.

Heparin and warfarin anticoagulation intensity as predictors of recurrence after deep vein thrombosis or pulmonary embolism: a population-based cohort study.

To test recommended anticoagulation measures as predictors of 180-day venous thromboembolism (VTE) recurrence, we identified all Olmsted County, MN residents with incident VTE over the 14-year period of 1984-1997, and followed each case (N = 1166) forward in time for VTE recurrence. We tested the activated partial thromboplastin time (APTT), international normalized ratio (INR), and other measures of heparin and warfarin anticoagulation as predictors of VTE recurrence while controlling for baseline and time-dependent characteristics using Cox proportional hazards modeling. Overall, 1026 (88%) and 989 (85%) patients received heparin and warfarin, respectively, and 85 (8%) developed VTE recurrence. In multivariable analyses, increasing proportions of time on heparin with an APTT ≥ 0.2 anti-X(a) U/mL and on warfarin with an INR ≥ 2.0 were associated with significant reductions in VTE recurrence, while the hazard with active cancer was significantly increased. Time from VTE onset to heparin start, duration of overlapping heparin and warfarin, and inferior vena cava (IVC) filter placement were not independent predictors of recurrence. At a heparin dose ≥ 30 000 U/d, the median proportion of time with an APTT ≥ 0.2 anti-X(a) U/mL was 92%, suggesting that routine APTT monitoring and heparin dose adjustment may be unnecessary. In summary, lower-intensity heparin and standard-intensity warfarin anticoagulation are effective in preventing VTE recurrence.