Small-Area Analysis of Treatment and Clinical Outcomes in Patients with Venous Thromboembolism in Denmark: A Nationwide Cohort Study

OBJECTIVES

 To investigate geographical variation in initiation and extended treatment with anticoagulants and clinical outcomes among patients hospitalized with first-time venous thromboembolism (VTE) in Denmark between 2007 and 2018.

METHODS

 Using nationwide health care registries, we identified all patients with a first-time VTE hospital diagnosis supported by imaging data from 2007 to 2018. Patients were grouped according to residential region (5) and municipality (98) at the time of VTE diagnosis. Cumulative incidence of initiation of and extended (beyond 365 days) anticoagulation treatment as well as clinical outcomes, including recurrent VTE, major bleeding, and all-cause death, were assessed. Sex- and age-adjusted relative risks (RRs) of the outcomes were computed when comparing across individual regions and municipalities. Overall geographic variation was quantified by computing the median RR.

RESULTS

 We identified 66,840 patients with a first-time VTE hospitalization. A difference in initiation of anticoagulation treatment of more than 20 percentage points between regions was observed (range: 51.9-72.4%, median RR: 1.09, 95% confidence interval [CI]: 1.04-1.13). Variation was also observed for extended treatment (range: 34.2-46.9%, median RR: 1.08, 95% CI: 1.02-1.14). The cumulative incidence of recurrent VTE ranged from 3.6 to 5.3% at 1 year (median RR: 1.08, 95% CI: 1.01-1.15). The difference remained after 5 years, and variation was also observed for major bleeding (median RR: 1.09, 95% CI: 1.03-1.15), whereas it appeared smaller for all-cause mortality (median RR: 1.03, 95% CI: 1.01-1.05).

CONCLUSION

 Substantial geographical variation in anticoagulation treatment and clinical outcomes occurs in Denmark. These findings indicate a need for initiatives to ensure uniform high-quality care for all VTE patients.

Activation of blood coagulation in pigs following lower limb gunshot trauma

A standardized, quantifiable gunshot trauma to one hind leg of fourteen anaesthetized and sedated pigs was used to investigate the extent to which an isolated gunshot trauma causes activation of blood coagulation. The traumatized pigs were mechanically ventilated in intensive care for 48 h before they were euthanized. Blood samples were drawn at baseline (t = 0), 24, 27 and 48 h after trauma to examine the late effects on haemostasis. The median energy absorption in the pigs was 27.57 (22.6-31.7) J/kg. This gunshot injury caused increased creatine kinase and body temperature and led to a combined metabolic and respiratory alkalosis; the pigs remained circulatory stable. Within the haemostatic system the trauma caused increased activated partial thromboplastin time at 48 h (P < 0.05), prothrombin time at 24 and 27 h (P < 0.05), fibrinogen and soluble fibrin concentration at 48 h (P < 0.05), and 24 h (P < 0.05), respectively. The platelet count, protein C activity, tissue factor concentration and trombin-antithrombin concentration decreased throughout the experiment (P < 0.05); the changes of antithrombin activity did not reach statistical significance. In conclusion, this study in pigs demonstrates that a standardized gunshot trauma to a hind leg activates blood coagulation without signs of organ failure or disseminated intravascular coagulation within 48 h.

Jet and ultrasonic nebulization of single chain urokinase plasminogen activator (scu-PA)

Recent studies have indicated that the deposition of intra-alveolar fibrin may play a central role in the pathogenesis of acute respiratory distress syndrome (ARDS). Our aim was to study whether the indigenous fibrinolytic agent (urokinase) normally present in the alveoli can be administered locally by nebulization in a recombinant zymogen form as single chain urokinase plasminogen activator (scu-PA). We aimed to characterize the particle size distribution, drug output, and enzymatic activity of scu-PA after nebulization with a Ventstream jet nebulizer (Medic-Aid, Bognor Regis, UK) and a Syst'AM DP-100 ultrasonic nebulizer (Pulmolink, Kent, UK). The particle size distribution was measured with a laser diffraction method and the drug output was determined by collection on filters. The amount of protein on the filters was determined with the Lowry method, and the enzymatic activity after nebulization was measured with a microtiter fibrin plate assay. The mass median diameter (MMD) of the scu-PA aerosol generated with the ultrasonic nebulizer was 3.69 (3.53-3.83) microm and with the jet nebulizer 2.96 (2.91-3.03) microm (p < 0.001). The drug output from the two nebulizers did not differ between nebulizers (p = 0.054). Fibrinolytically active scu-PA was generated with both nebulizers, but in contrast to jet nebulization, ultrasonic nebulization caused partial inactivation of scu-PA (p < 0.001). In conclusion, nebulization of scu-PA with the jet nebulizer is superior to ultrasonic nebulization in terms of particle size distribution and preservation of fibrinolytic activity.

Dietary factor VII activation does not increase plasma concentrations of prothrombin fragment 1+2 in patients with stable angina pectoris and coronary atherosclerosis

Studies in healthy subjects showed that blood coagulation factor VII (FVII) is activated postprandially after consumption of high-fat meals, but accompanying thrombin formation has not been demonstrated. In patients with coronary atherosclerosis, the arterial intima is supposed to present more tissue factor, the cofactor of FVII, to circulating blood; therefore, thrombin formation in response to FVII activation is more likely to occur in such patients. This hypothesis was tested in a randomized crossover study of 30 patients (aged 43 to 70 years) with stable angina pectoris and angiographically verified coronary atherosclerosis. They were served a low-fat (5% of energy from fat) breakfast and lunch and a high-fat (40% of energy from fat) breakfast and lunch on 2 different days. Venous blood samples were collected at 8:15 AM (fasting), 12:30 PM, 2:00 PM, 3:30 PM, and 4:45 PM and analyzed for triglycerides, activated FVII (FVIIa), FVII protein concentration (FVII:Ag), prothrombin fragment 1+2 (F1+2), and soluble fibrin. Triglyceride levels increased from fasting levels on both diets, but they increased most markedly on the high-fat diet. FVIIa and FVIIa/FVII:Ag increased with the high-fat diet and decreased with the low-fat diet. For both diets, FVII:Ag and F1+2 decreased slightly. No postprandial changes were observed for soluble fibrin. Postprandial mean values of triglycerides, FVIIa, FVII:Ag, and FVIIa/FVII:Ag were significantly higher for the high-fat diet than for the low-fat diet. Our findings confirm that high-fat meals cause immediate activation of FVII. The clinical implication is debatable because FVII activation was not accompanied by an increase in plasma F1+2 concentrations in patients with severe atherosclerosis. However, a local thrombin generation on the plaque surface cannot be excluded.

Multicentre randomised study of computerised anticoagulant dosage. European Concerted Action on Anticoagulation

BACKGROUND

The demand for anticoagulant treatment is increasing. We compared the benefits of computer-generated anticoagulant dosing with traditional dosing decided by experienced medical staff in achieving target international normalised ratios (INRs).

METHODS

In five European centres we randomly assigned 285 patients in the stabilisation period and stabilised patients to the computer-generated-dose group (n=137) or traditional-dose group (n=148). Centres had a specialist interest in oral anticoagulation but no previous experience with computer-generated dosing. The computer program calculated doses and times to next visit. Our main endpoint was time spent in target INR range (Rosendaal method).

FINDINGS

For all patients combined, computer-generated dosing was significantly beneficial overall in achieving target INR (p=0.004). The mean time within target INR range for all patients and all ranges was 63.3% (SD 28.0) of days in the computer-generated-dose group compared with 53.2% (27.7) in the traditional-dose group. For the stabilisation patients alone, computer-generated doses led to a non-significant benefit in all INR ranges (p=0.06), whereas in the stable patients the benefit was significant (p=0.02).

INTERPRETATION

The computer program gave better INR control than the experienced medical staff and at least similar standards to the specialised centres should be generally available. Clinical outcome and cost effectiveness remain to be assessed.