Ashrani, Aneel A.

Abstract Objectives Despite more than 40 years of experience performing the Bethesda assay (BA), poor intra- and interlaboratory precision remains the biggest laboratory challenge to date. Methods The BA procedure was modeled using stochastic simulation techniques to determine the precision of the BA up to dilutions of 1:4,096, to estimate the minimum significant relative change at various inhibitor titers, and to understand the laboratory procedural variables that could significantly affect the performance of the BA at high dilutions. Results Selecting the lowest dilution tube with a residual activity closest to 25% for calculating the reported Bethesda titer (BT), using a factor activity assay with a coefficient of variation less than or equal to 7.5% in the range of 15% to 50% factor activity level, performing the factor activity measurement in replicates, and minimizing pipette volumetric error resulted in the lowest imprecision in the reported BT. The factor neutralization kinetics of the inhibitor appear to have little impact on the precision of the assay if the incubation time is greater than 90 minutes. Conclusions This in silico model will assist future laboratory efforts in standardizing the quantification of specific coagulation factor inhibitors and improving the precision of the reported results.

Abstract Background: Active cancer is an independent predictor of recurrent venous thromboembolism (VTE; hazard ratio=2.2–4.2). However, whether the risk of VTE recurrence among active cancer patients can be further stratified by tumor site or presence of metastases is uncertain. Objectives: To estimate and compare the cumulative incidence of VTE recurrence by tumor site and presence of metastases among active cancer patients with incident VTE. Study Design and Population: Retrospective cohort study of Olmsted County, MN residents with active cancer who lived >1 day after a first-lifetime deep vein thrombosis or pulmonary embolism over the 35-year period, 1966–2000 (n=418). 25 patients with oral (6), bone (1), skin (4), soft tissue (3), eye (1) and other/unknown (10) were excluded, leaving 393 remaining patients. Measurements: Baseline demographic and clinical characteristics, tumor site, presence and location of tumor metastases, and date of first recurrent VTE. Tumor site and metastases were tested as potential predictors of time-to-recurrent VTE using the Cox proportional hazards model. Results: 114 of 393 patients with active cancer developed recurrent VTE over 764 person-years of follow-up. The cumulative incidence of recurrent VTE at seven, 30, 90, and 180 days, 1, 5, and 10 years was 1.9%, 10.3%, 18.3%, 22.3%, 28.7%, 44.5%, and 53.5%, respectively. After adjusting for age and gender, tumor site was an independent predictor of first VTE recurrence (p<0.01). The hazard of VTE recurrence was over 2-fold higher for lung cancer patients compared to the lowest recurrence group (kidney, bladder and other genitourinary cancer; HR=2.04, 95% CI: 0.88, 4.70, p=0.096), and the hazard for brain and pancreatic cancer was nearly 2-fold higher (HR=1.9 for each, p=0.22, 0.24, respectively). The hazard of recurrence among hematological; breast and ovarian; gastric, colon, and liver; and prostate cancer patients did not differ significantly from the lowest recurrence group. Univariately, the presence of metastases at cancer diagnosis was not associated with recurrent VTE (HR=1.16; 95% CI: 0.79, 1.69, p=0.45). Conclusions: Tumor site is an independent predictor of VTE recurrence after adjusting for age and gender. In particular, lung, brain and pancreatic cancer patients have the highest risk for recurrence and these patients should be considered for secondary prophylaxis. Disease severity, as reflected by metastatic disease at cancer diagnosis, is not a predictor of recurrence.

Abstract Background: While currently-diagnosable hematological cancer is a potent VTE risk factor (RR range =12–32), whether undiagnosable hematological cancer is a risk factor is uncertain. Objective: To estimate the hazard of subsequent hematological cancer among incident VTE patients with no apparent active hematological cancer within ± 3 months of the VTE event. Methods: In a population-based cohort study, we followed Olmsted County, MN residents with incident VTE over the 27-year period, 1973–1999, and previously matched Olmsted County residents without VTE, who survived with no apparent active hematological cancer within ± 3 months of the VTE event or a routine medical visit date, respectively, forward in time through their complete medical records in the community for hematological cancer. Data were abstracted on baseline demographic and clinical characteristics, type and stage of hematological cancer, and any prior solid tumor treatments. For cases and controls, hematological cancer-free survival from the event date was estimated by the Kaplan Meier method, and the homogeneity of survival curves was examined by the log-rank test. Cox proportional hazards regression was used to adjust for covariates. Results: 1860 VTE cases (56% females) and 1890 controls (53% females) were followed for 16,497 and 15,320 person-years, respectively, conditional on surviving 3-months free of hematological cancer. 43 VTE cases and 24 controls developed hematological cancer at a median of 63.5 months (range 0.7 – 334 months). The median age for cases was 63.2 years compared to 67.8 years for the controls (p<0.001). Hematological cancer types included non-Hodgkin’s lymphoma (n=19), chronic lymphocytic leukemia (n=11), acute myeloid leukemia (n=1), multiple myeloma (n=9), myeloproliferative disorders (n=10), and myelodysplastic syndromes (n=14). Case status was not univariately associated with subsequent hematologic cancer (HR=1.42; 95% CI: 0.85, 2.39; p=0.18). After adjusting for age, also associated with cancer, case status was significantly associated with hematological cancer (HR=1.90; 95% CI: 1.13, 3.20; p=0.015). Conclusions: Incident VTE patients have nearly a two-fold increased risk of subsequent hematological cancer. We hypothesize that VTE can be the initial manifestation of an occult hematological cancer clone.

Abstract Background: Hematological cancer patients are at an increased risk for VTE (RR range = 12–32). However, whether VTE risk among such patients can be further stratified is uncertain. Objective: To test hematological cancer type, stage, stage progression and chemotherapy as potential risk factors for VTE among active hematological cancer patients after controlling for other previously-identified VTE risk factors. Methods: Using the resources of the Rochester Epidemiology Project, Mayo Clinic Master Diagnostic Index and Mayo Clinic Tumor Registry, we identified all Olmsted County, MN residents with active hematological cancer over the 28-year period, 1973–2000. From this prevalence cohort, we identified 86 patients with no prior VTE (controls) who were matched on age and date of hematological cancer diagnosis to 86 hematological cancer patients with incident VTE over the same time frame (cases). For all cases and controls, we reviewed the complete medical records in the community for baseline and hematological cancer-related characteristics. Hematological cancers were re-staged at the dates of the cancer and VTE diagnosis. We tested these characteristics as potential risk factors for VTE in active hematological cancer using conditional logistic regression. Results: In an initial multivariate analysis that included body mass index (BMI), hospitalization, and any infection or central venous catheter placement within 90 days prior to the VTE event, VTE was significantly associated with hospitalization (OR=6.70; p<0.001), and marginally associated with any infection (OR=2.18; p=0.09). After adjusting for the above variables, chemotherapy administered within the preceding 90 days was significantly associated with VTE (OR=4.25; p=0.02), while stage progression was marginally associated (OR=4.79; p=0.10). Compared to all other hematological cancer types, acute leukemia (OR=5.95; p=0.01) and non-Hodgkin’s lymphoma (OR=2.61; p=0.01) were associated with VTE. However, after adjusting for BMI, hospitalization, any infection and central venous catheter, only non-Hodgkin’s lymphoma was independently associated with VTE (OR=3.79, p=0.009), while acute leukemia was not (OR=2.66, p=0.35). Conclusions: Hematological cancer type (in particular, non-Hodgkin’s lymphoma and possibly acute leukemia), recent hospitalization, recent chemotherapy, and possibly stage progression and recent infection, are risk factors for VTE among patients with active hematological cancer.

AbstractIntroductionHemostatic prophylaxis (HP) is recommended for patients with bleeding disorders (PWBD) before invasive procedures. However, evidence‐based guidelines are needed to determine optimal HP strategies.AimTo determine outcomes of HP for PWBD undergoing colonoscopy.MethodsWe 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.ResultsDuring 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).ConclusionThe 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.