Ultrasound elastography is useful to distinguish acute and chronic deep vein thrombosis.

Essentials Ultrasound elastography uses tissue deformation to assess the relative quantification of its elasticity. Compression and duplex ultrasonography may be unable to correctly determine the thrombus age. Ultrasound elastography may be useful to distinguish between acute and chronic deep vein thrombosis. The exact determination of the thrombus age could have both therapeutic and prognostic implications. BACKGROUND: Background Ultrasound elastography (UE) imaging is a novel sonographic technique that is commonly employed for relative quantification of tissue elasticity. Its applicability to venous thromboembolic events has not yet been fully established; in particular, it is unclear whether this technique may be useful in determining the age of deep vein thrombosis (DVT). Thus, the aim of this study was to assess the role of UE in distinguishing acute from chronic DVT. Methods Consecutive patients with a first unprovoked acute and chronic (3 months old) DVT of the lower limbs were analyzed. Patients with recurrent DVT or with a suspected recurrence were excluded. The mean elasticity index (EI) values of acute and chronic popliteal and femoral vein thrombosis were compared. The accuracy of the EI in distinguishing acute from chronic DVT was also assessed by measuring the sensitivity, specificity, positive and negative predictive values, and likelihood ratios. Results One-hundred and forty-nine patients (mean age 63.9 years, standard deviation 13.6; 73 males) with acute and chronic DVT were included. The mean EI of acute femoral DVT was higher than that of chronic femoral DVT (5.09 versus 2.46), and the mean EI of acute popliteal DVT was higher than that of chronic popliteal DVT (4.96 versus 2.48). An EI value of > 4 resulted in a sensitivity of 98.9% (95% confidence interval [CI] 93.3-99.9), a specificity of 99.1% (95% CI 94.8-99.9), a positive predictive value of 91.1% (95% CI 77.9-97.1), a negative predictive value of 98.6% (95% CI 91.3-99.9), a positive likelihood ratio of 13.23 (95% CI 93-653) and a negative likelihood ratio of 0.001 (95% CI 0.008-0.05) for acute DVT. Conclusions UE appears to be a promising technique for distinguishing between acute and chronic DVT. Larger prospective studies are warranted to confirm our preliminary findings.

Once versus twice daily enoxaparin for the initial treatment of acute venous thromboembolism.

Essentials In venous thromboembolism (VTE), it is uncertain if enoxaparin should be given twice or once daily. We compared the 15- and 30-day outcomes in VTE patients on enoxaparin twice vs. once daily. Patients on enoxaparin once daily had fewer major bleeds and deaths than those on twice daily. The rate of VTE recurrences was similar in both subgroups. SUMMARY: Background In patients with acute venous thromboembolism (VTE), it is uncertain whether enoxaparin should be administered twice or once daily. Methods We used the RIETE Registry data to compare the 15- and 30-day rates of VTE recurrence, major bleeding and death between patients receiving enoxaparin twice daily and those receiving it once daily. We used propensity score matching to adjust for confounding variables. Results The study included 4730 patients: 3786 (80%) received enoxaparin twice daily and 944 once daily. During the first 15 days, patients on enoxaparin once daily had a trend towards more VTE recurrences (odds ratio [OR], 1.79; 95% confidence interval [CI], 0.55-5.88), fewer major bleeds (OR, 0.42; 95% CI, 0.17-1.08) and fewer deaths (OR, 0.32; 95% CI, 0.13-0.78) than those on enoxaparin twice daily. At day 30, patients on enoxaparin once daily had more VTE recurrences (OR, 2.5; 95% CI, 1.03-5.88), fewer major bleeds (OR, 0.40; 95% CI, 0.17-0.94) and fewer deaths (OR, 0.58; 95% CI, 0.33-1.00). On propensity analysis, patients on enoxaparin once daily had fewer major bleeds at 15 (hazard ratio [HR], 0.30; 95% CI, 0.10-0.88) and at 30 days (HR, 0.16; 95% CI, 0.04-0.68) and also fewer deaths at 15 (HR, 0.37; 95% CI, 0.14-0.99) and at 30 days (HR, 0.19; 95% CI, 0.07-0.54) than those on enoxaparin twice daily. Conclusions Our findings confirm that enoxaparin prescribed once daily results in fewer major bleeds than enoxaparin twice daily, as suggested in a meta-analysis of controlled clinical trials.

The short- and long-term risk of venous thromboembolism in patients with acute spinal cord injury: a prospective cohort study.

Venous thromboembolism (VTE) is a frequent complication in the acute setting after spinal cord injury (SCI). Less is known about the long-term risk of VTE in these patients. It was the aim of this study to prospectively evaluate the short- and long-term risk of VTE in a cohort of patients after acute SCI and during rehabilitation and post-rehabilitation follow-up period. From January 2003 to November 2007 all consecutive adult patients admitted to a Spinal Rehabilitation Unit (RU) after surgical treatment in three Neurosurgical Units for SCI, were enrolled. After an accurate evaluation of their neurosurgical medical records the patients were prospectively evaluated for VTE occurrence. Ninety-four patients (80 males; mean age 40.3 years, SD 15.9) were recruited. All the patients received thromboprophylaxis with low-molecular-weight heparin combined with compressive stockings during hospitalization (median duration 7 months, IQR 4.5-8.8). Over a median follow-up period of 36.3 months (IQR 4.4-48) after SCI, VTE was diagnosed in 22 patients (23.4%) The majority of VTE events were recorded during the first three months of follow-up (34.4 VTE events/100 patient-years in the first 3 months and 0.3 VTE events/100 patient-years thereafter); age over 45 years (HR 8.4, 95% CI 3-23.5), previous VTE (HR 6.0, 95% CI 1.6-23.3) and paraplegia (HR 4.7, 95% CI 1.6-13.7) were independently associated with the occurrence of VTE. In conclusion, the risk of VTE in patients suffering from SCI is high despite the use of thromboprophylaxis, in particular in some patients categories. However, this risk appears to be limited to the first 3 months after the index event.

Safety and efficacy of low-dose fondaparinux (1.5 mg) for the prevention of venous thromboembolism in acutely ill medical patients with renal impairment: the FONDAIR study.

BACKGROUND: Renal impairment is common, affecting around 40% of acutely ill medical patients, and is associated with an increased risk of both venous thromboembolism (VTE) and bleeding. The clinical benefit of effective thromboprophylactic strategies may be outweighed in these patients by an excessive rate of hemorrhage. OBJECTIVE: To assess the safety and efficacy of lower prophylactic doses of fondaparinux in acutely ill medical patients with renal impairment. PATIENTS/METHODS: We carried out a multicenter, investigator-initiated, prospective cohort study. Patients at risk of VTE with a creatinine clearance between 20 and 50 mL min(-1) were treated with fondaparinux 1.5 mg qd for a minimum of 6 to a maximum of 15 days. The primary outcome was the incidence of major bleeding; secondary outcomes were clinically relevant non-major bleeding (CRNMB) and symptomatic VTE. RESULTS: We enrolled 206 patients with a mean age of 82 years, mean creatinine clearance of 33 mL min(-1) , and a mean Charlson co-morbidity index of 8.2. One patient had major bleeding (0.49%, 95% confidence interval [CI] 0.03-3.10), eight had CRNMB (3.88%, 95% CI 1.81-7.78) and three developed symptomatic VTE (1.46%, 0.38-4.55). Twenty-three patients (11.17%, 7.36-16.48) died. No independent predictors of bleeding were found at univariate analysis. CONCLUSIONS: The addition of moderate to severe renal impairment to patients with traditional risk factors for VTE identified a population of very elderly acutely ill medical patients potentially at high risk of both VTE and bleeding complications. The recently approved lower prophylactic dose of fondaparinux appears to be a safe and relatively effective strategy in these patients.

Management of primary care patients with suspected deep vein thrombosis: use of a therapeutic dose of low-molecular-weight heparin to avoid urgent ultrasonographic evaluation.

BACKGROUND: Out of hospital management of patients with suspected deep vein thrombosis (DVT) can be problematic. The accuracy of clinical prediction rules in the primary care setting may be inadequate, D-dimer testing may not be available, and the cost-effectiveness of urgent ultrasonographic evaluation is uncertain. OBJECTIVE: The purpose of this study was to determine the efficacy and safety of an empiric single therapeutic dose of low-molecular weight heparin (LMWH) in the time interval preceding ultrasound investigation in patients presenting to primary care physicians (PCPs) for suspicion of DVT. METHODS: Consecutive patients with suspected DVT who presented to the office of a PCP outside regular thrombosis center working hours were enrolled. All eligible patients received a single therapeutic dose of LMWH (100 anti-Xa IU kg(-1) weight) and were scheduled to undergo clinical and instrumental evaluation at the thrombosis center the morning after. Clinical events were documented after a 3-month follow-up. RESULTS: A total of 534 consecutive patients with suspected DVT were included in this study; of these 102 patients had subsequent diagnosis of DVT. We detected no episodes of pulmonary embolism, major bleeding, or death during the 18-h window between the administration of LMWH and objective evaluation. Of the 432 patients in whom diagnosis of DVT was subsequently excluded, only three (0.7%; CI: 0.2-2.0%) developed venous thromboembolic events during the 3-month follow-up period. CONCLUSIONS: Empiric treatment with a single therapeutic dose of LMWH is effective and safe for outpatients with suspected DVT initially managed in a primary care setting. This strategy has the potential to reduce the need for urgent diagnostic imaging.

Magnesium and cardiovascular drugs: interactions and therapeutic role.

Numerous experimental, epidemiological and clinical studies have pointed out a relevant role for magnesium deficiency in the development of many cardiovascular diseases. Some pharmacological treatments may interfere with magnesium turnover, and magnesium deficiency may alter the pharmacokinetics and pharmacodynamics of some cardiovascular drugs. Loop and thiazide-like diuretics increase magnesiuresis, and total bodily magnesium deficiency may appear during prolonged treatment with diuretically active doses of these drugs. The potassium retaining agents, such as amiloride, triamterene and spironolactone, tend to retain magnesium but they are not magnesium-retaining substances to the extent to which they are potassium-retaining diuretics. The interaction between magnesium and digitalis is complex. Magnesium, acting as an indirect antagonist of digoxin at the sarcolemma Na(+)-K(+)-ATPase pump, reduces cardiac arrhythmias due to digoxin poisoning. Recent controlled studies have shown that treatment with magnesium significantly reduces the frequency and complexity of ventricular arrhythmias in digoxin-treated patients with congestive heart failure without digoxin toxicity. Magnesium improves the efficacy of digoxin in slowing the ventricular response in atrial fibrillation. Digoxin reduces tubular magnesium reabsorption, and in patients with congestive heart failure this interaction may be cumulative with other causes of magnesium deficiency (diuretics, diet, poor intestinal absorption). The complex and potentially life-threatening interactions between magnesium and some cardiovascular drugs suggest that magnesium status should be carefully monitored in patients receiving such drugs. Therapy with magnesium is rapidly acting, has a safe toxic-therapeutic ratio, is easy to administer and titrate. The correction of magnesium deficit should therefore always be considered for patients with cardiopathy.