Heit, John A.

Background: Whether VTE risk can be further stratified among patients with neurologic disease and leg paresis is unknown. Objective: To identify independent risk factors for deep vein thrombosis (DVT) and pulmonary embolism (PE) among patients with neurologic disease and leg paresis. Methods: Using the population-based resources of the Rochester Epidemiology Project, we identified all Olmsted County, MN residents with incident DVT or PE over the 45-year period, 1966 to 2010. We performed a case-control study nested within the Olmsted County population with incident VTE associated with neurologic disease and leg paresis over the 18-year period, 1988-2010 (n=192). For each VTE case, we identified 1 Olmsted County resident with neurologic disease, leg paresis and no VTE (control) matched to each case on sex, date of birth (+/- 5 years), calendar year (+/- 1 year) and duration of medical records. Using conditional logistic regression, we tested duration of paresis (index-3 months, 3-12 months, and > 12 months), paresis etiology, and degree of immobility as potential risk factors for VTE after adjusting for other known VTE risk factors, including hospitalization for major surgery or acute medical illness, trauma/fracture, and active cancer. Results: In univariate analyses of the 192 pairs, trauma/fracture, hospitalization for major surgery or for acute medical illness, active cancer, duration of paresis, and degree of immobility were associated with VTE. In the multivariable analysis, hospitalization for acute medical illness, active cancer, degree of immobility (ambulatory without/with assistance, function from a wheelchair base, bed bound; OR: 2.60; 95%Cl: 1.65-4.11); p=<0.0001) were independent predictors of VTE. Conclusion: Among patients with neurologic disease and leg paresis, VTE risk can be further stratified by hospitalization for acute medical illness, active cancer and degree of immobility; these patients should be considered for VTE prophylaxis.

Objective Activated platelets serve as a catalyst for thrombin generation. Furthermore, oral MHT may carry greater thrombotic risk than transdermal products. This study compared effects of oral and transdermal MHT on platelet characteristics including platelet‐derived microvesicles (MV) in recently menopausal women. Methods Platelets and MV were prepared from blood of a subset of women (n=117) enrolled in the Kronos Early Estrogen Prevention Study prior to and after 4 years of treatment with either oral conjugated equine estrogen (0.45 mg, oCEE), transdermal 17β estradiol (50 µg/day, tE2), each with intermittent progesterone (200 mg/day for 12 days a month), or placebo pills and patch. Results Platelet count, and activated platelet P‐selectin and fibrinogen‐binding receptor expression were similar across groups. Numbers of tissue factor positive and platelet‐derived MV increased significantly in the tE2 compared to placebo. Conclusions Four years of MHT did not increase thrombogenic characteristics of platelets. Thrombotic risk associated with oral MHT most likely involves liver‐derived proteins than platelets per se. Differential effects of oCEE and tE2 on circulating MV may reflect the hormonal composition of the two formulations on non‐genomic pathways in circulating platelets. Funding This work was supported by grants from the Aurora Foundation to the Kronos Longevity Research Institute, NIH HL90639, UL1TR00013 1 , American Heart Association‐ Scientist Development Grant, AHA 08‐30503Z, American Heart Association, Grant‐in‐Aid, 12GRNT12050147, and the Mayo Foundation.

Menopausal hormone treatments (MHT) may limit progression of CIMT, a measure of atherosclerosis, but pose a risk for ischemic stroke. To test candidate gene variation for an association with CIMT, DNA from 714 women participating in KEEPS, a clinical trial of MHT to prevent progression of atherosclerosis, was genotyped using custom Illumina Infinium iSelect chemistry. Single nucleotide polymorphisms (SNPs; 13,229) were genotyped within 769 genes within the anticoagulant, procoagulant, fibrinolytic or innate immunity pathways. Of these SNPs, 75 were removed due to call rate<0.95, relatedness, duplication, and misidentification; 1275 were removed for quality control. There were 504 ancestry informative markers (AIM). Percent of European ancestry using AIM, age at enrollment and pulse pressure correlated positively with CIMT. Using logistic regression to adjust for these, one SNP (rs2236935 of MAP4K4 on chromosome 2) associated positively with CIMT (p‐value = 5.771e‐06). This gene encodes a protein of the serine/threonine protein kinase family involved in cytokine signaling pathways related to innate immunity, development of type II diabetes, and response to environmental stress. Whether this SNP remains associated with changes in CIMT in women randomized to hormonal treatment in KEEPS remains to be determined. (Supported by grants from the Aurora Foundation, NIH HL90639 and the Mayo Foundation)

Risk of CAD increases at menopause and platelets contribute to the etiology of CAD. We hypothesized that individual variation in platelet procoagulant activity at menopause correlates with the extent of CAD as reflected by coronary artery calcification ( CAC ). We developed several novel and global assays of platelet procoagulant activity: dense (ATP release) and alpha (P‐selectin expression) granule secretion and GPα IIb β 3 fibrinogen‐binding (PAC1 binding) to ADP stimulation, and prostaglandin E 1 (PEG 1 ) sensitivity as a surrogate for prostacyclin sensitivity. Platelets were prepared from venous blood collected from women screened for the Kronos Early Estrogen Prevention Study (n=125; mean±SD age=52.5±2.4 years) within 19.4±9.2 months of last menses. Baseline CAC score was determined. Of conventional CAD risk factors, only systolic blood pressure correlated with positive CAC score (n=23). ATP secretion tended to be less in women with positive CAC scores and was negatively correlated with blood glucose (P<0.001). P‐selectin expression and PAC1 binding increased with total cholesterol (P<0.05). PEG 1 sensitivity increased with increasing age and waist circumference (P<0.05). These results indicate that platelet functions change with age and in association with conventional risk factors for the disease in women at menopause. Supported by the Kronos Longevity Research Institute and NIH HL90639.

Abstract Objective. —To review the current state of the art regarding the role of the clinical laboratory in diagnostic testing for the factor V Leiden (FVL) thrombophilic mutation (and other protein C resistance disorders), and to generate, through literature reviews and opinions of recognized thought-leaders, expert consensus recommendations on methodology and diagnostic, prognostic, and management issues pertaining to clinical FVL testing. Data Sources, Extraction, and Synthesis. —An initial thorough review of the medical literature and of current best clinical practices by a panel of 4 experts followed by a consensus conference review, editing, and ultimate approval by the majority of a panel of 28 additional coagulation laboratory experts. Conclusions. —Consensus recommendations were generated for topics of direct clinical relevance, including (1) defining those patients (and family members) who should (and should not) be tested for FVL; (2) defining the preferred FVL laboratory testing methods; and (3) defining the therapeutic, prophylactic, and management ramifications of FVL testing in affected individuals and their family members. As FVL is currently the most common recognized familial thrombophilia, it is hoped that these recommendations will assist laboratorians and clinicians caring for patients (and families) with this common mutation.

Abstract Background. —The reported operating characteristics of the plasma fibrin D-dimer level for the diagnosis of acute pulmonary embolism vary widely. Objective. —To determine the sensitivity, specificity, predictive value, and clinical utility of the D-dimer for the diagnosis of pulmonary embolism, and to describe the effect of D-dimer assay method (enzyme-linked immunosorbent assay [ELISA], latex agglutination, membrane ELISA) and discriminate level, patient location at onset, comorbid disease, duration and intensity of concurrent heparin administration, and duration of symptoms on these operating characteristics. Design. —Prospective laboratory investigation. Setting. —Community and tertiary care teaching hospital. Patients. —Consecutive patients with suspected acute pulmonary embolism referred for pulmonary angiography from April 1993 through March 1996. Measurements. —Baseline characteristics, the duration and intensity of heparin anticoagulation, the time interval between symptom onset and plasma D-dimer testing, pulmonary angiography, and the D-dimer level on the day of pulmonary angiography. Results. —Of 105 consenting patients, 33 (31%) had a positive pulmonary angiogram. The D-dimer sensitivity/negative predictive value for the ELISA, latex agglutination (American Bioproducts Co/Diagnostica Stago and Biopool International), and membrane ELISA were 100%/100%, 94%/94%, 100%/100%, and 97%/96%, respectively, at a discriminate level of 250 μg/L or less. The clinical utility, defined as the prevalence of a negative test, ranged from 17% to 33%. D-dimer sensitivity was unaffected by patient location at onset, comorbid disease, or heparin therapy but was inversely related to the duration of symptoms. Conclusions. —The sensitivity of the plasma fibrin D-dimer for the diagnosis of pulmonary embolism depends on the assay method, the assay-specific discriminate level, and the duration of symptoms. At the appropriate discriminate level, the plasma D-dimer is a sensitive but nonspecific test for the diagnosis of pulmonary embolism.

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 &gt;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&lt;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: Most trials of standard heparin and warfarin therapy used the 3- to 6-month cumulative incidence of venous thromboembolism (VTE) recurrence as the primary efficacy outcome. Consequently, the effect of heparin anticoagulation intensity on short-term VTE recurrence after controlling for other predictors of recurrence (e.g., active cancer, neurological disease with extremity paresis) is uncertain. Objectives: To test standard heparin anticoagulation intensity, using activated partial prothrombin time (APTT) data, as an independent predictor of 14-day VTE recurrence. Measurements: Using the resources of the Rochester Epidemiology Project, we identified all Olmsted County, MN residents with an incident deep vein thrombosis or pulmonary embolism over the 14-year period, 1984–1997 (n=1165). We followed each case (conditional on surviving one day) forward in time through their complete medical records in the community for first VTE recurrence. We collected date of incident VTE onset, start and stop dates of heparin and warfarin, and date, time and result of all APTT and platelet count values. Using these and other measures of standard heparin therapy as time-dependent variables, we tested the intensity of heparin anticoagulation as an independent predictor of 14-day VTE recurrence while controlling for other baseline characteristics using Cox proportional hazards modeling. Results: Of the 1165 patients, 1026 (88%) and 989 (85%) received heparin and warfarin, respectively, and 254 (22%) developed recurrent VTE over 5461 person-years of follow-up; 23 recurred within 14 days. In the multivariate analysis, the independent predictors of 14-day recurrence included female gender (HR=3.06, 95%CI: 1.05, 8.91; p=0.04) and neurologic disease with extremity paresis (HR=6.01, 95%CI: 1.93, 18.66; p&lt;0.01); the hazard of recurrence was marginally increased for active cancer (HR=2.21, p=0.13). Warfarin therapy (HR=0.44, p=0.11) and a therapeutic APTT within the first 24 hours of therapy (HR=0.41, p=0.08) were marginally protective, but age, body mass index, time interval between VTE onset and start of heparin, and other measures of heparin anticoagulation intensity (e.g., proportion of time in therapeutic APTT range, etc) were not predictors of recurrence. Three patients developed new and persistent thrombocytopenia beginning 2, 4 and 5 days after starting heparin, respectively and prior to VTE recurrence. Conclusions: VTE recurrence is uncommon within 14 days after starting heparin therapy. Female gender and neurologic disease with extremity paresis are independent predictors of 14-day recurrence, and active cancer may be an additional predictor. Warfarin therapy and a therapeutic APTT within the first 24 hours may predict a reduced recurrence risk. However, other measures of heparin anticoagulation intensity were non-predictive. Heparin-induced thrombocytopenia may partially account for early VTE recurrence.