Benefits of prophylaxis versus on-demand treatment in adolescents and adults with severe haemophilia A: the POTTER study

Rigorous evidence is lacking on long-term outcomes of factor VIII (FVIII) prophylaxis initiated in adolescent or adult patients with severe haemophilia A. The prospective, open-label Prophylaxis versus On-demand Therapy Through Economic Report (POTTER) study (ClinicalTrials.gov NCT01159587) compared long-term late secondary prophylaxis (recombinant FVIII-FS 20-30 IU/kg thrice weekly) with on-demand treatment in patients aged 12 to 55 years with severe haemophilia A. The annual number of joint bleeding episodes (primary endpoint), total bleeding episodes, orthopaedic and radiologic (Pettersson) scores, health-related quality of life (HRQoL), pharmacoeconomic impact, and safety were evaluated over a > 5-year period (2004-2010). Fifty-eight patients were enrolled at 11 centres in Italy; 53 (27 prophylaxis, 26 on demand) were evaluated and stratified into 2 age subgroups (12-25 and 26-55 years). Patients receiving prophylaxis experienced a significantly lower number of joint bleeding episodes vs the on-demand group (annualised bleeding rate, 1.97 vs 16.80 and 2.46 vs 16.71 in younger and older patients, respectively; p=0.0043). Results were similar for total bleeding episodes. Prophylaxis was associated with significantly fewer target joints (p< 0.001), better orthopaedic (p=0.0019) and Pettersson (p=0.0177) scores, better HRQoL, and fewer days of everyday activities lost (p< 0.0001) but required significantly higher FVIII product consumption. The POTTER study is the first prospective, controlled trial documenting long-term benefits of late secondary prophylaxis in adolescents and adults with severe haemophilia A. The benefits of reduced bleeding frequency, improved joint status, and HRQoL may offset the higher FVIII consumption and costs.

The Wells rule and D-dimer for the diagnosis of isolated distal deep vein thrombosis

BACKGROUND

Pretest clinical probability with the Wells rule and D-dimer have been widely investigated for the diagnosis of symptomatic proximal deep vein thrombosis (DVT) of the lower limbs, but they have not been formally tested for symptomatic isolated distal DVT diagnosis.

OBJECTIVE

To evaluate the diagnostic accuracy of the Wells rule and D-dimer for isolated distal DVT.

DESIGN, SETTING, AND PATIENTS

This was a single-center, cross-sectional study including 873 consecutive outpatients with suspected DVT, in whom pretest clinical probability determination, D-dimer determination (STA Liatest; cut-off of < 500 ng mL(-1) ) and complete compression ultrasonography of both lower limbs were performed.

RESULTS

The isolated distal DVT prevalence was 12.4% (90/725). The sensitivity of the Wells rule for isolated distal DVT was 47% (95% confidence interval [CI] 36-57%), the specificity was 74% (95% CI 70-77%), and the negative and positive predictive values were 91% (95% CI 88-93%) and 20% (95% CI 15-26%), respectively. Patients with isolated distal DVT had higher D-dimer levels than patients without DVT (1759 ± 1576 vs. 862 ± 1079 ng mL(-1) , P = 0.0001). D-dimer was negative in 13 patients with isolated distal DVT. D-dimer sensitivity and specificity for isolated distal DVT were 84% (95% CI 75-91%) and 50% (95% CI 46-54%), respectively, with a negative predictive value of 96% (95% CI 93-98%). In patients with low pretest clinical probability, the D-dimer negative predictive value was 99% (95% CI 95-100%).

CONCLUSION

In clinically suspected DVT with negative proximal compression ultrasonography, pretest clinical probability with the Wells rule has a low diagnostic accuracy for isolated distal DVT. D-dimer has a better negative predictive value, but alone it does not exclude isolated distal DVT. In patients with low pretest clinical probability, D-dimer had a negative predictive value of > 95% for isolated distal DVT.

Evolution of untreated calf deep-vein thrombosis in high risk symptomatic outpatients: the blind, prospective CALTHRO study

The natural history of calf deep-vein thrombosis (DVT) is still uncertain and it is debated whether it warrants to be diagnosed and treated. We aimed to investigate the complication rate of untreated isolated calf DVT (ICDVT). Symptomatic outpatients were prospectively managed with serial compression ultrasonography (SCUS). Those without proximal DVT and with likely pre-test clinical probability (PCP) or altered D-dimer received immediate subsequent complete examination of calf deep veins (CCUS) by a different operator. The result of CCUS was kept blind both to the managing doctor and the patient and disclosed after three months. Primary outcome was the rate of venous thromboembolism at three months. We examined 431 subjects (196 males; median age 68.0 years) in whom five outcomes were recorded (1.2%; 95% confidence intervals [CI]: 0.4-2.7). If CCUS results had been available, outcomes would have been recorded in 3/424 patients (0.7%; 95% CI: 0.2-2.1) with two events in subjects negative at both serial and complete CUS. ICDVT was diagnosed in 65 subjects (15.3%; 95% CI: 12-19); of whom 59 remained uneventful (one was lost to follow-up). A significant higher rate of outcomes was recorded in subjects with than without ICDVT (5/64; 7.8%; 95% CI: 3-17 vs. 3/351; 0.8%; 95% CI: 0-2; p=0.003). However, after excluding two events picked at serial CUS in subjects with ICDVT, the difference became barely significant (3/64; 4.7%; 95% CI: 1-13; p=0.049). Thrombotic evolution of untreated ICDVT in high-risk subjects may be relevant. Larger studies are needed to address this issue.

No early signs of atherosclerotic alterations in carriers of inherited thrombophilia

BACKGROUND

Congenital thrombophilia is a risk factor for venous thromboembolism (VTE). Whether it is associated with increased risk of arterial disease is today a matter of debate. We aimed to look for early signs of atherosclerotic alterations in carriers of inherited thrombophilic alterations (ITA).

METHODS

Between January 2006 and September 2008 ultrasonography assessment of the carotid arteries with measurement of intima-media thickness (IMT), and determination of the ankle/brachial pressure index (ABI), was performed in: a) 161 carriers of ITA (deficiency of antithrombin, protein C or S, factor V Leiden or prothrombin G20210A mutations), 84 of whom with previous VTE, and b) 180 subjects without ITA, matched for age, sex and previous VTE. All subjects were <66 year old.

RESULTS

Carotid plaques were found in 8 subjects [3 (1.9%) with ITA]. Increased IMT values (>1mm) were detected in 6 subjects with and 1 without thrombophilia (p=0.055). The prevalence of IMT values>90(th) percentile was not different in subjects with/without thrombophilia (15.2% vs 11.6%, p=0.416). At multivariate analysis only age was significantly associated with increased odds ratios for IMT values>90(th) percentile. No subjects had abnormal (<0.9) ABI values.

CONCLUSIONS

The present study, the first to investigate the presence of atherosclerotic markers in relatively young subjects with inherited thrombophilia, did not find a particular prevalence of signs of early atherosclerotic markers in these subjects.

Thalidomide-dexamethasone as up-front therapy for patients with newly diagnosed multiple myeloma: thrombophilic alterations, thrombotic complications, and thromboprophylaxis with low-dose warfarin

BACKGROUND

Venous thromboembolism (VTE) is a major complication of myeloma therapy recently observed with the increasing use of up-front thalidomide and dexamethasone (thal-dex). The pathogenesis of thal-induced VTE is not well recognized, and the role of prothrombotic factors, especially of thrombophilic abnormalities, is not yet determined.

MATERIAL AND METHODS

Two hundred and sixty-six patients with newly diagnosed multiple myeloma (MM) were primarily treated with thal-dex in preparation for subsequent high-dose therapy and autologous stem-cell transplantation. Out of these 266 patients, 190 were evaluated for thrombophilic alterations at baseline, and 125 of them were also re-assessed after thal-dex therapy.

RESULTS

The presence of genetic thrombophilic polymorphisms among patients with MM was superimposable to that of normal controls and was associated with a twofold increase in the relative risk of VTE. aAPCR and elevated factor VIII levels were frequent, albeit transient, alterations and were not associated with a significant increase in the risk of VTE. Two hundred and forty-six patients received a thromboprophylaxis with fixed low-dose warfarin (1.25 mg/day) during thal-dex therapy. Of these patients (or 10.6%), 26 had symptomatic VTE events. Their patients-years rate of VTE (35.5%) was significantly lower in comparison with the 86.2% rate recorded among the first 19 patients who initially entered the study and did not receive any kind of thromboprophylaxis (P = 0.043).

CONCLUSIONS

On the basis of these data, a baseline thrombophilic work up is not recommended in patients with receiving up-front thal-dex. For these patients, fixed low-dose warfarin may be a valuable prophylaxis against VTE.

Predictive value of D-dimer test for recurrent venous thromboembolism after anticoagulation withdrawal in subjects with a previous idiopathic event and in carriers of congenital thrombophilia

BACKGROUND

We have shown that normal D-dimer levels obtained after the discontinuation of oral anticoagulant treatment (OAT) has a high negative predictive value for recurrent venous thromboembolism (VTE). The aim of the present study was to assess the predictive value of D-dimer for recurrent VTE in subjects with a previous unprovoked event who are either carriers of inherited thrombophilia or not.

METHODS AND RESULTS

We prospectively evaluated 599 patients (301 males) with a previous VTE episode. They were repeatedly examined for D-dimer levels after OAT withdrawal and were screened for inherited thrombophilic alterations. Alterations were detected in 130 patients (21.7%), factor V Leiden (70 patients; 2 of whom were homozygotes) and prothrombin mutation (38 patients) were the most prevalent ones. Recurrent events were recorded in 58 subjects (9.7%) during a follow-up of 870.7 patient-years. Altered D-dimer levels at 1 month after OAT withdrawal were associated with a higher rate of subsequent recurrence in all subjects investigated, especially in those with an unprovoked qualifying VTE event (hazard ratio, 2.43; 95% confidence interval, 1.18 to 4.61) and in those with thrombophilia (hazard ratio, 8.34; 95% confidence interval, 2.72 to 17.43). The higher relative risk for recurrence of altered D-dimer was confirmed by multivariate analysis after adjustment for other risk factors. The negative predictive value of D-dimer was 92.9% and 95.8% in subjects with an unprovoked qualifying event or with thrombophilia, respectively.

CONCLUSIONS

D-dimer levels measured 1 month after OAT withdrawal have a high negative predictive value for recurrence in subjects with unprovoked VTE who are either carriers or not carriers of congenital thrombophilia.