Changes in bone density during long-term administration of low-molecular-weight heparins or acenocoumarol for secondary prophylaxis of venous thromboembolism

BACKGROUND

Indications for long-term anticoagulation are expanding. Osteoporosis is a complication which can develop after prolonged treatment with unfractionated heparin and is probably multifactorial. Data on osteoporosis associated with low-molecular-weight heparins (LMWH) are contradictory. Vitamin K participates in bone metabolism and since oral anticoagulants antagonize vitamin K, their use may also increase the risk of osteoporosis.

AIM

To assess and compare the effects of long-term secondary venous thromboembolic prophylaxis with LMWH or acenocoumarol on bone structure.

METHODS

We assessed bone mineral density (BMD) by densitometry in 86 patients receiving LMWH or acenocoumarol for 3-24 months. The initial BMD was compared to the final result expressed as the percentage difference. The Z-score was also assessed and defined for individual patients as the number of standard deviations of BMD from its ideal value calculated for age and sex groups.

RESULTS

Excessive decrease in BMD was evidenced, which seemed to relate to the duration as well as type of treatment. At 1 and 2 years of follow-up, the mean decrease in BMD of the femur was 1.8% and 2.6% in patients on acenocoumarol and 3.1 and 4.8% in patients on enoxaparin, respectively.

CONCLUSIONS

Long-term exposure to treatment and prophylaxis of venous thromboembolism cause a modest but progressive decrease in BMD, more evident in patients on LMWH than on acenocoumarol. It might be advisable to perform densitometry before starting long-term anticoagulation and to repeat it every 12 months, especially in patients with concomitant risk factors for osteoporosis in order to identify patients in need of its prophylaxis.

Vena cava filter occlusion and venous thromboembolism risk in persistently anticoagulated patients: a prospective, observational cohort study

BACKGROUND

Inferior vena cava (IVC) filter placement may be life-saving, but after contraindications to anticoagulation remit, patient management is uncertain.

METHODS

We followed patients who had venous thromboembolism, followed by treatment with permanent IVC filter placement, and were anticoagulated long-term as soon as safety allowed. We conducted annual physical examinations and ultrasound surveillance of the lower extremity deep veins and of the IVC filter site. Clot detected at the filter site was treated with graded intensities of anticoagulation, depending on the clot burden.

RESULTS

Symptomatic DVT occurred in 24 of 121 patients (20%; 95% CI, 14%-28%); symptomatic pulmonary embolism (one fatal) was diagnosed in six patients (5%; 95% CI, 2%-10%). There were 45 episodes of filter clot in 36 patients (30%; 95% CI, 22%-38%). The rate of major bleeding (6.6%) was similar to that of a concurrent persistently anticoagulated cohort without IVC filters (5.8%).

CONCLUSIONS

If therapeutic anticoagulation can be safely begun in patients with IVC filters inserted after venous thromboembolism, further management with clinical surveillance, including ultrasound examination of the IVC filter and graded degrees of anticoagulation therapy if filter clot is detected, has a favorable prognosis. This approach appears valid for patients with current IVC filter and can serve as a comparison standard in subsequent clinical trials to optimize clinical management of these patients.

Optical properties of phenylene–thiophene-based polyazomethine thin films

Thin films of new aromatic polyazomethines, containing thiophene rings in their polymer chain structures, were obtained by the chemical vapor deposition method, via a polycondensation process from thiophene-2,5-dicarbaldehyde and one of four different aromatic diamines, as initial monomers. Spectroscopic ellipsometry, attenuated total reflectance mode of Fourier transform infrared spectroscopy, atomic force microscopy, and wide-angle X-ray diffraction techniques have been used to characterize these films. However, the optical transmission and reflectivity measurements, within the wide spectral UV-Vis-NIR range (0.5–6.2 eV), were the basic method of presented investigations. On the basis of optical measurements, the absorption coefficient spectra of these thin films were obtained and the absorption edge parameters, that is, the energy gap ( EG) and Urbach energy ( EU), were calculated in a way typical for amorphous semiconductors. These parameters allowed one to evaluate the length of conjugation and the extension of localized, defect states inside the energy gap, respectively, and to discuss the electronic transitions, being dependent on the chemical structure and conformation of polymer chains. Optical properties of these new phenylene–thiophene-based polyazomethine films were compared with their entirely phenylene counterparts. In general, the energy gaps of investigated films were clearly smaller (about 0.2 eV) than those of their phenylene counterparts, confirming that the presence of thiophene rings in polyazomethine structures improves conjugation.

[Doppler studies of gestational diabetes in the third trimester]

PURPOSE

Gestational diabetes (GDM) is related to increased maternal and neonatal morbidity. Maternal hyperglycemia causes fetal hyperglycemia and consequently fetal hyperinsulinism. The impaired glucose metabolism will lead to prenatal and postnatal complications. The main issue of this study is the influence of GDM in evaluating Doppler flow measurements in the umbilical artery (UA).

MATERIALS AND METHODS

Pregnancies from gestational age > 34 + 0 were included in this case control study. The study period was 18 months. The last Doppler measurement in pregnancies with GDM (diet-controlled and insulin-dependent) was compared to the healthy control group. Our collected data included the last prenatal Doppler flow recordings (resistance index (RI) in the umbilical artery (UA)).

RESULTS

In women with diet-controlled GDM, a significant decrease in the RI (p = 0.002) in the UA has been observed. Insulin-treated diabetic and healthy control pregnancies showed no difference in the RI.

CONCLUSION

Doppler flow examinations with RI measurements in patients with GDM differ significantly with respect to healthy controls. In insulin-treated women the RI indices are not different from the control group, while in the diet-controlled group a significant decrease was noted and additionally might show a possible maternal metabolic dysfunction.

Thermal and optical properties of PMMA films reinforced with Nb2O5 nanoparticles

The article presents the thermal and physical properties of PMMA composite films with the addition of Nb2O5 nanoparticles. The addition of nanoparticles to PMMA mainly influenced the optical transmission and glass transition temperature of composite films compared to pure PMMA. It is clearly visible in the results of the conducted ellipsometric and differential scanning calorimetry tests. X-ray studies showed that the heat treatment of the samples resulted in the ordering of the polymer structure (flattening of the polymer chains). Examining the surface of the samples with scanning electron microscopy, it can be seen that Nb2O5 nanoparticles formed unusual, branched formations resembling "snowflakes".

[Pulmonary embolism in course of deep vein thrombosis of lower extremities in patient wit bilateral femoral bone fracture after car accident injuries]

The incidence of deep vein thrombosis in Western World is estimated at about 1 case/1000/year and of pulmonary embolism at 0.5 case/1000/year. Mortality in untreated pulmonary embolism is 30%. With adequate treatment (anticoagulation) it can be decreased to 2-8%. Deep vein thrombosis and pulmonary embolism are frequent complications of various surgical procedures, especially of orthopedic interventions on hip joint. When surgery has to be performed in patient with high risk of pulmonary embolism, anticoagulant prophylaxis should be performed. Venous thromboembolic disease is the most important cause of mortality in trauma patients. We present a case of 46 years old man with bilateral fracture of femoral bone after car accident injury in whom signs of deep venous thrombosis and pulmonary embolism were observed despite the use of anticoagulant prophylaxis.

Thermal and optical properties of P3HT:PC70BM:ZnO nanoparticles composite films

The results of studies on the influence of zinc oxide nanoparticles (ZnO-NPs) on the structural, thermal and optical properties of thin films of mixtures of phenyl-C71-butyric acid methyl ester (PCBM) with poly[3-hexylthiophene] (P3HT) of various molecular weights are described in this article. The structural properties of the layers of: polymers, mixtures of polymers with fullerenes and their composites with ZnO-NPs were investigated using X-ray diffraction. Whereas their glass transition temperature and optical parameters have been determined by temperature-dependent spectroscopic ellipsometry. The presence of ZnO-NPs was also visible in the images of the surface of the composite layers obtained using scanning electron microscopy. These blends and composite films have also been used as the active layer in bulk heterojunction photovoltaic structures. The molecular weight of P3HT (Mw = 65.2; 54.2 and 34.1 kDa) and the addition of nanoparticles affected the power conversion efficiency (PCE) of the obtained solar cells. The determined PCE was the highest for the device prepared from the blend of P3HT:PCBM with the polymer of the lowest molecular weight. However, solar cells with ZnO-NPs present in their active layer had lower efficiency, although the open-circuit voltage and fill factor of almost all devices had the same values whether they contained ZnO-NPs or not. It is worth noting that thermal studies carried out using temperature-dependent ellipsometry showed a significant effect of the presence of ZnO-NPs on the value of the glass transition temperature, which was higher for composite films than for films made of a polymer-fullerene blend alone.

[Secondary prophylaxis of venous thromboembolism: analysis of 49 fatal cases]

The analysis of 49 fatal cases of venous thromboembolism--VTE (15% of total ambulatory patients number during long observation was performed. The advanced age of patients, multiple risk factors, underlying circulatory and respiratory tract diseases, malignancies, previous episodes of VTE especially with secondary pulmonary hypertension were the most important factors determining fatal prognoses in those patients.

[Implantation of LGM inferior vena cava filters in patients with chronic pulmonary hypertension during a course of major vessel thromboembolism--observation of 18 patients]

CTEPH have not been widely recognised until recently. Introduction of the new, sophisticated, non-invasive diagnostic tools accounts for rapid progress in that field. Patients with high pulmonary hypertension have a very poor prognosis. Medical treatment (vasodilators, anticoagulants) does not change outcome. Pulmonary thromboendarterectomy is the only therapeutic option for the patients. It is essential to prevent further episodes of pulmonary embolism both over the long term and during the high risk perioperative period by means of inferior vena cava filters. In the Department of Medicine, Institute of Tuberculosis and Lung Diseases 18 LGM ivc filters have been inserted in patients with CTEPH since 1994. In 7 patients PTE was performed-in 5 cases good result was achieved, 2 patients died after surgery. In the latter group 5 patients died mainly because of severe heart failure. Only one non-fatal episode of pulmonary embolism was observed. It should be concluded that the LGM ivc filters are safe and effective in preventing episodes of pulmonary embolism in patients with CTEPH.

[LGM inferior vena cava filters--observation of 79 patients]

The aim of the study was to assess effectiveness and safety of the LGM inferior vena cava (IVC) filters in patients with venous thromboembolic disease. In the Department of Internal Medicine of Institute of Tuberculosis and Lung Diseases in Warsaw 79 LGM IVC filters have been inserted since 1993. Indications for filters placement were as follows: recurrent pulmonary embolism (pe) despite anticoagulation--17 patients (pts), severe bleeding complications of thrombolytic or anticoagulant therapy--11 pts, contraindications for thrombolytic and/or anticoagulant treatment--5 pts, massive pe--14 pts, chronic thromboembolic-major vessel pulmonary hypertension (CTEPH)--30 pts, extensive deep vein thrombosis of lower limbs or vena cava inferior in patients with urgent indications for surgery--24 pts. Each filter placement was preceded by cavography. The diagnostic procedures (mainly ultrasonography) were performed after 3-6 and 12 months in the first year then once yearly during follow-up period. Oral anticoagulants (OA) or low-molecular-weight heparins (LMWH) were instituted in the majority of patients. 58 patients are still alive, 21 patients died. Only two non-fatal episodes of recurrent pe were documented. Other complications were rare and insignificant. We have not observed excess rate of recurrent deep venous thrombosis nor thrombosis at the filter site. The LGM IVC filters are effective and safe in such selectively chosen group of patients.

[Massive pulmonary artery embolism complicated by acute pulmonary heart disease]

43-year old woman, with considerable overweight had been admitted to Intensive Medical Care Unit with suspicion of pulmonary embolism (PE). The patient had the limb immobilized in gypsum for last several weeks. This episode was tangled with recurrent thrombosis of deep veins in the left limb, treated with heparin and oral anticoagulants irregularly without sufficient control. Taking into consideration the data of anamnesis, clinical picture and the results of ECG, chest X-ray, gasometric and echocardiographic examination we got much closer to the recognition of PE. Our suspicion of PE was confirmed by the result of pulmonary angiography. Indications for thrombolytic treatment (r-tPA) had been established. During the following hours considerable improvement of general state was observed. The therapy was continued with constant drip infusion of heparin. No prolongation of therapeutic PTT was observed. The deficit of AT III was diagnosed. In this situation the patient was given AT III to obtain normalization of its level and therapeutic extension of PTT. Therefore there were settled indications for the operation of uterus with myoma changes. As the rich thrombolytic material in the leg's vein was found the patient was implanted LGM Filter, with excellent prophylactic effect (no PE in perioperative period). The clinical course of our case enabled to present most of diagnostic, therapeutic and preventive methods applied in venous thromboembolism.

[Secondary ambulatory prophylaxis of venous thromboembolism: outcome of patients who were lost to follow-up]

We have attempted to determine the outcome of 87 out-patients who were lost from follow-up. Several factors have been assessed: causes of lost from follow-up duration of oral anticoagulation, recurrent venous thromboembolic events, cause of death (if applicable).

[Clinically silent pulmonary embolism in patients with proximal deep venous thrombosis]

In 18 patients with proximal deep venous thrombosis (PDVT) confirmed by phlebography, no symptoms and signs of pulmonary embolism (PE) were observed. All patients were treated with nadroparin. During first 6 days of treatment in all patients perfusion lung scans were performed. 8 patients (44.4%) of all group developed lung scans positive for PE (silent PE). Period of successful treatment of PDVT was 10 days. No evidence of recurrent PE were observed during the period of treatment. We conclude that: 1. Frequency of silent PE in patients with PDVT is very high-lack of symptoms and signs of PE does not exclude the presence of PE in this group of patients. 2. In all patients with PDVT perfusion lung scan should be performed even in cases with no symptoms and signs of PE. 3. Low molecular weight heparins administered subcutaneously are effective in treatment either silent PE or PDVT.

[Low doses of rtPA administered as a bolus in treatment of clinically acute massive pulmonary embolism]

12 patients (7 male and 5 female) with confirmed pulmonary embolism (PE) with: angiography-5 cases, conventional contrast-enhanced CT-2 cases, echocardiography-2 cases, autopsy-3 cases were diagnosed as clinically acute PE. Criteria of clinically acute PE were: cardiac arrest-1 case-2 cases, shock-1 case, acute cor pulmonale-9 cases and acute cor pulmonale with shock. All patients were treated with heparin, administered with therapeutic prolongation of aPTT. Clinically acute PE (if possible confirmed with angiography, TC and/or echocardiography) was treated with rtPA administered in 10 minutes lasting bolus in doses 0.6-0.8 mg per kg of body weight (50 mg of rtPA during 10 minutes administered into peripheral veins). In 9 patients with pulmonary hypertension, significant decrease of tricuspidal gradient (measured echocardiographically during several hours after administration of rtPA) was documented. Improvement in PaO2, SaO2 and decrease of heart rate and respiratory rate were also achieved. No serious bleeding complications were observed after mentioned treatment. Control investigations (conventional contrast-enhanced CT and spiral CT) performed several days after rtPA administration revealed thrombus in pulmonary artery. We conclude: I rtPA administered in bolus simultaneously with heparin significantly decreased pulmonaryhypertension; rtPA administered simultaneously with heparin is safe method of treatment of PE; hemodynamic improvement after administration of rtPA is not univocal with full fibrynolitic effect.

[Pulmonary thrombendarterectomy in treatment of patients with chronic thromboembolic pulmonary hypertension]

20 consecutive patients with thromboembolic pulmonary hypertension underwent pulmonary thromboendarterectomy. Mean pulmonary artery pressure decreased from mean 49.9 +/- 9.8 to 25.1 +/- 8.8 mm Hg (p < 0.0001), pulmonary vascular resistance decreased from mean 5.58 +/- 2.58 to 1.62 +/- 0.79 mm Hg/l*min-1 (p < 0.0001) and cardiac output increased from 3.71 +/- 1.18 to 6.92 +/- 1.64 l/min. Sixteen patients had marked clinical improvement. Two patients died in early and 2 patients in late postoperative period due to unrelieved pulmonary hypertension and postoperative complications.

[Secondary anticoagulant prophylaxis with low molecular heparins or oral anticoagulants and bone mineral density]

A broad spectrum of indications for low molecular weight heparin (LMWH) requires an assessment of side effects especially during prolonged administration. There are common risk factors for venous thromboembolism (VTE) and osteoporosis; heparin is "the drug of choice" for VTE treatment. The aim of our study was to assess the effect of treatment and prophylaxis with LMWH (enoxaparine sodium) and oral anticoagulant (acenocoumarol) for bone structure. Material consists of in- and outpatients. 49 densitometries were performed in 31 patients (in 15 cases double examination). We observed a decrease of bone mineral density in comparison to the initial examination in most cases: mean change of bone mass for examined areas was 3.05%.

[Effect of localization of pulmonary arterial changes on echocardiographic indices of right heart function and their correlation with exercise capacity: comparison of arterial and thromboembolic pulmonary hypertension]

AIM

To assess correlation between exercise tolerance and Doppler-derived indices of right ventricular (RV)--pulmonary arterial coupling in patients with different location of vascular lesions causing pulmonary hypertension (PH).

MATERIAL

45 patients: 21 with thromboembolic (TE-PH) and 24 with arterial PH defined as systolic pulmonary arterial pressure (SPAP) > 40 mm Hg. The two groups were similar as far as SPAP (74,8 +/- 15,2 vs 76.5 +/- 14,1 mm Hg, p = ns) and distance covered during 6 minute walk test (339 +/- 116 vs 320 +/- 127, p = ns) are concerned.

RESULTS

Flow velocity curve in the RV outflow tract were different in the two groups. Time from onset to peak velocity of ejection (acceleration time, AcT) as well as to midsystolic deceleration were shorter in TE-PH then in arterial PH (59.0 +/- 6.3 vs 68.1 +/- 15.4 msec, p = 0.015 and 123.8 +/- 17.9 vs 137.9 +/- 29.7 msec, p = 0.071, respectively). In the whole studied group as well as in arterial PH significant correlation between exercise tolerance and Doppler-derived indices of RV--pulmonary arterial coupling were found (r = 0.51, p < 0.001 and r = 0.72, p = < 0.001, respectively). Interestingly, no such relationship was found in TE-PH, (r = 0.16, p = ns).

CONCLUSION

In contrast to arterial PH, pressure wave prematurely reflected from the intraluminal thrombi seem to disturb the RV ejection pattern and its correlation with exercise tolerance in TE-PH. Whether progression or effects of treatment on arterial PH can be assessed by monitoring changes in Doppler-derived indices of RV--pulmonary arterial coupling requires further studies.