Persisting autoimmune heparin-induced thrombocytopenia after elective abdominal aortic aneurysm repair: a case report.

Persisting heparin-induced thrombocytopenia (HIT) is characterized by ongoing thrombocytopenia more than 7 days after stopping heparin. It is part of cases referred to as autoimmune HIT (aHIT). In contrast to typical HIT cases, aHIT involves heparin-independent platelet activation mechanism highlighted by a strongly positive functional assay done without heparin. We report the first case of persisting HIT after an elective abdominal aortic aneurysm repair presenting with arterial and venous thrombosis, and describe the potential role of intravenous immunoglobulin in such patients.

A case report of severe nasal ischemia from cold agglutinin disease and a novel treatment protocol including HBOT.

Cold agglutinin disease (CAD) is a rare condition leading to blood agglutination and autoimmune hemolytic anemia. Cutaneous ischemia resulting from CAD in the head and neck is uncommon. Treatment regimens and outcomes vary widely in the literature and no clear protocol exists. This manuscript describes a patient with CAD who developed severe ischemia of the nose that resolved completely without sequellae following a medical regimen of aspirin, low molecular weight heparin, nitroglycerin ointment and hyperbaric oxygen therapy (HBOT). To our knowledge, this is the first reported case where nitroglycerin ointment or HBOT was successfully employed in the treatment of this complication.

Outcome of central venous catheter associated upper extremity deep vein thrombosis in cancer patients.

INTRODUCTION: Data on efficacy and safety of using low molecular weight heparin in cancer patients with catheter-related upper extremity deep vein thrombosis is scarce and the risk of recurrent venous thromboembolism after discontinuation of anticoagulation is unknown. MATERIAL AND METHODS: We conducted a retrospective cohort study including consecutive cancer outpatients assessed for the management of symptomatic central venous catheter-associated proximal upper extremity deep vein thrombosis. RESULTS: Of 99 included patients, 89 were treated with one month of full therapeutic weight-adjusted dose of low molecular weight heparin followed by an intermediate dose. Median duration of anticoagulation was 124 days (range 40 to 1849). No recurrent venous thromboembolism and two major bleeding episodes occurred during the first 3 months of treatment. Eighty patients were followed-up after anticoagulation discontinuation for a median of 632 days (range 6 to 2495). Central venous line was pulled in all patients in remission and in 26 of the 29 patients (89.6%) with active cancer. Five recurrences were observed during follow-up. The cumulative probability of recurrent venous thromboembolism was higher in patients whose cancer was active at the time of anticoagulation discontinuation as compared with those in remission (22.2% (95% CI: 0 to 40.6) vs. 2.3% (95% CI: 0 to 6.7)). CONCLUSION: The risk of venous thromboembolism recurrence in patients whose central venous catheter has been pulled out and cancer is in remission appears low following anticoagulation discontinuation and after a minimum of 3 months of full/intermediate dose.

Effect of 200µG/day of vitamin K1 on the variability of anticoagulation control in patients on warfarin: a randomized controlled trial.

BACKGROUND: Controversy exists whether low-dose vitamin K supplementation can improve anticoagulation control in patients with unstable anticoagulation under warfarin. In a single- centre randomized, double-blind, placebo-controlled study, we evaluated the effectiveness of 200 µg/day of vitamin K1 in patients with unstable control under warfarin. METHODS: Effectiveness of Vitamin K1 supplementation was primarily assessed by the percentage (%) of Time-in-Therapeutic-Range (TTR) and secondarily by the standard deviation (SD) of the patient's INR values; the proportion of out-of-range INRs; and the number of dose changes on warfarin. Their change scores were obtained by subtracting the mean value in the 6 months pre-randomization from the mean value in the 6 months post-randomization. Multivariable linear-regressions identified factors associated with anticoagulation instability. RESULTS: Fifty out of 54 patients were analyzed (intervention: n=26; placebo: n=24). Most indications (87%) for anticoagulation were venous thromboembolism (VTE). The intervention was associated with a greater reduction in the change scores for the SD of INRs between the pre and post-randomization periods compared with placebo. The mean change score was -0.259±0.307 with the intervention and -0.046±0.345 with placebo (p=0.026). There was no effect on the change scores of the (%) TTR (p=0.98), the number of INRs out-of-range (p=0.58) and the number of dose changes (p=0.604). Factors independently associated with increased variability in the SD of INRs were increased alcoholic drinks/week (p=0.017), dosing errors (p=0.0009) and missed INR appointments (p=0.035). CONCLUSION: Vitamin K1 supplementation reduces the SD of INRs as an indicator of the variability in anticoagulation control in patients treated with warfarin for VTE.

Hospital mortality due to pulmonary embolism and an evaluation of the usefulness of preventative interventions.

BACKGROUND: Mortality rates due to pulmonary embolism (PE) are difficult to estimate often due to the presence of comorbid disease. OBJECTIVES: To determine the accuracy of hospital records in identifying PE cases, PE-related mortality, and the number of PE-related deaths which are potentially preventable. METHODS: Retrospective chart review of PE cases hospitalized at The Ottawa Hospital over an 8 year period. Cases were reviewed to determine accuracy of coding, as well as the certainty with which PE was the cause of death. In PE-related deaths, a determination was made as to whether any interventions may have been life-saving. RESULTS: 498 cases of 612 (81%) cases coded as PE were correctly coded. 111 (22%) died during hospitalization, 63% of deaths were attributed to PE. The presence of a cardiorespiratory comorbidity or cancer was independently associated with an increased rate of death due to PE. 54% of PE-related deaths were determined to be potentially preventable, most commonly by appropriate DVT prophylaxis. A significantly higher number of cancer patients as compared to non-cancer patients may have potentially had their death due to PE prevented by an inferior vena cava filter (IVCF). Systemic thrombolysis was deemed to be potentially life-saving in 1/38 PE-related deaths. CONCLUSION: Hospital mortality due to clinically recognized PE can be determined by chart review of PE cases identified using the ICD coding system. Death due to PE is often potentially preventable; in the subgroup with cancer and DVT/PE, an IVCF may be a potentially useful intervention to prevent death due to PE. Prospective studies are needed to confirm these results.

Multicenter evaluation of a new quantitative highly sensitive D-dimer assay, the Hemosil D-dimer HS 500, in patients with clinically suspected venous thromboembolism.

INTRODUCTION: D-dimer testing is widely used in conjunction with clinical pretest probability (PTP) for venous thromboembolism (VTE) exclusion. We report on a multicenter evaluation of a new, automated, latex enhanced turbidimetric immunoassay [HemosIL D-Dimer HS 500, Instrumentation Laboratory (IL)]. MATERIALS AND METHODS: 747 consecutive outpatients with suspected proximal deep vein thrombosis (DVT, n=401) or pulmonary embolism (PE, n=346) were evaluated at four university hospitals in a management study with a 3 month follow-up. Samples were tested at each center using the new D-dimer assay on an automated coagulation analyzer [ACL TOP (IL)], with clinical cut-off for VTE at 500 ng/mL (FEU). RESULTS: The sensitivity and negative predictive value (NPV) were 100% for all PTP subgroups (no false negative results); for both sensitivity and NPV the lower limit of the 95% CI in patients with moderate/low PTP was higher than 95%. The overall specificity was 45.1% (95%CI: 41.1-49.3%). Higher specificity value was recorded in the low PTP subgroup [49.2% (95%CI: 41.7-56.7)]. No significant differences were found between patients suspected of having DVT or PE; sensitivity and NPV were 100%. The reproducibility of the assay was good, being the total CVs% less than 10% for D-dimer concentration near the clinical cut-off. CONCLUSIONS: The new, highly sensitive D-dimer assay proved to be accurate when used for VTE diagnostic work-up in outpatients. Based on 100% sensitivity and NPV and lower limit of the 95% CI higher than 95%, the assay can be used as a stand-alone test in patients with non high PTP.

Diagnosis and treatment of deep-vein thrombosis.

Deep-vein thrombosis (DVT) is a common condition that can lead to complications such as postphlebitic syndrome, pulmonary embolism and death. The approach to the diagnosis of DVT has evolved over the years. Currently an algorithm strategy combining pretest probability, D-dimer testing and compression ultrasound imaging allows for safe and convenient investigation of suspected lower-extremity thrombosis. Patients with low pretest probability and a negative D-dimer test result can have proximal DVT excluded without the need for diagnostic imaging. The mainstay of treatment of DVT is anticoagulation therapy, whereas interventions such as thrombolysis and placement of inferior vena cava filters are reserved for special situations. The use of low-molecular-weight heparin allows for outpatient management of most patients with DVT. The duration of anticoagulation therapy depends on whether the primary event was idiopathic or secondary to a transient risk factor. More research is required to optimally define the factors that predict an increased risk of recurrent DVT to determine which patients can benefit from extended anticoagulant therapy.

Factor XIII Val34Leu variant is protective against venous thromboembolism: a HuGE review and meta-analysis.

It has been suggested that a G-to-T transition in exon 2 of the factor XIIIA gene resulting in a substitution of leucine for valine at amino acid 34 (FXIII Val34Leu) protects against venous thromboembolism (VTE). However, the evidence to date is insufficient to incorporate testing for the FXIII Val34Leu variant into clinical practice. To determine whether genotypes with the FXIII Val34Leu variant are protective against VTE, the authors performed a meta-analysis of 12 studies with genotyping for the FXIII Val34Leu variant (3,165 objectively diagnosed VTE cases and 4,909 controls). When a random-effects model was used, the combined odds ratios for VTE were 0.63 (95% confidence interval: 0.46, 0.86) for the homozygotes of the FXIII Val34Leu variant, 0.89 (95% confidence interval: 0.80, 0.99) for the heterozygotes, and 0.85 (95% confidence interval: 0.77, 0.95) for the homozygotes and heterozygotes combined. Potential sources of heterogeneity and potential bias were explored. The meta-analysis provided evidence that the FXIII Val34Leu variant has a small, but significant protective effect against VTE. Since VTE is a complex disorder, this information, along with results of ongoing studies to identify additional genetic factors underlying VTE, will be crucial in developing accurate risk profiles to identify individuals at higher risk of VTE.

Embolization of a huge tricuspid valve bacterial vegetation.

A case of a woman who had tricuspid valve bacterial endocarditis is presented. Her course was complicated by persistent disseminated intravascular coagulation and acute renal failure, followed by pulmonary embolization of the vegetation. Transthoracic echocardiography showed almost complete obstruction of the right pulmonary artery. The case demonstrates the impressive size to which right-sided infective vegetations can progress and the relative paucity of symptoms and hemodynamic derangements with which they may be associated, even in the context of potentially life-threatening complications.