Ultrasound-assisted versus conventional catheter-directed thrombolysis for acute iliofemoral deep vein thrombosis: 1-year follow-up data of a randomized-controlled trial

Essentials Acute iliofemoral deep vein thrombosis can be treated with catheter-directed thrombolysis (CDT). We performed a randomized trial comparing conventional CDT versus ultrasound-assisted CDT (USAT). Clinical and duplex sonographic outcomes at 12 months were similar in the CDT and USAT groups. In both groups, incidence of postthrombotic syndrome was very low with good quality of life.

SUMMARY

Background In patients with acute iliofemoral deep vein thrombosis (IFDVT), catheter-directed thrombolysis (CDT) aims to prevent the postthrombotic syndrome (PTS). Adding intravascular high-frequency, low-power ultrasound energy to CDT does not seem to improve the immediate thrombolysis results but its impact on clinical outcomes at 12 months is not known. Patients/Methods In this randomized-controlled trial, 48 patients (mean age 50 ± 21 years; 52% women) with acute IFDVT were randomized to conventional CDT (n = 24) or ultrasound-assisted CDT (USAT; n = 24). In both groups, a fixed-dose thrombolysis regimen (20 mg r-tPA over 15 h) was used, followed by routine stenting of residual venous obstruction. At 12 months, PTS and venous disease severity (Villalta score and revised Venous Clinical Severity Score [rVCSS]), disease-specific quality of live (QOL; CIVIQ-20) and duplex-sonographic outcomes were assessed. Results Among the 45 surviving patients, 40 (89%; 95% confidence interval [CI] 76-96%) patients were free from PTS (defined as Villalta score < 5 points; 83%, 95% CI 61-95% in the USAT and 96%, 95% CI 77-100% in the CDT group), with a similar mean total Villalta score of 2.3 ± 2.9 vs. 1.7 ± 1.6, and a mean total rVCSS of 3.0 ± 3.5 vs. 2.7 ± 2.9 in the USAT and the CDT groups, respectively. Both groups had good disease-specific QOL with a CIVIQ-20 score of 29.4 ± 11.8 vs. 26.1 ± 7.8, respectively. Primary (100% vs. 92%) and secondary (100% vs. 96%) iliofemoral patency rates and presence of femoro-popliteal venous reflux (39% vs. 33%) were similar in both groups. Conclusion The addition of intravascular ultrasound energy to conventional CDT for the treatment of acute IFDVT did not have any impact on relevant clinical or duplex sonographic outcomes, which were favorable in both study groups. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier:NCT01482273.

Hemodynamic Characterization of Peripheral Arterio-venous Malformations

Peripheral arterio-venous malformations (pAVMs) are congenital vascular anomalies that require treatment, due to their severe clinical consequences. The complexity of lesions often leads to misdiagnosis and ill-planned treatments. To improve disease management, we developed a computational model to quantify the hemodynamic effects of key angioarchitectural features of pAVMs. Hemodynamic results were used to predict the transport of contrast agent (CA), which allowed us to compare our findings to digital subtraction angiography (DSA) recordings of patients. The model is based on typical pAVM morphologies and a generic vessel network that represents realistic vascular feeding and draining components related to lesions. A lumped-parameter description of the vessel network was employed to compute blood pressure and flow rates. CA-transport was determined by coupling the model to a 1D advection-diffusion equation. Results show that the extent of hemodynamic effects of pAVMs, such as arterial steal and venous hypertension, strongly depends on the lesion type and its vascular architecture. Dimensions of shunting vessels strongly influence hemodynamic parameters. Our results underline the importance of the dynamics of CA-transport in diagnostic DSA images. In this context, we identified a set of temporal CA-transport parameters, which are indicative of the presence and specific morphology of pAVMs.

FTIR analysis of the phase content in low-density polyethylene

The phase content of a low-density polyethylene was studied by analysis of the CH2 rocking vibrations in non-oriented films prepared from the press (P-films) or from solution (S-films). Spectral simulations of the transmission spectra give the mass fractions of the orthorhombic phase αortho and of two noncrystalline phases (monoclinic-like and amorphous). The values of αortho (IR) are compared to αortho (i) where (i) stands for the X-ray diffraction, density, and DSC techniques. New results are obtained concerning the orthorhombic order and the change of phase content with aging. A two-phase analysis is justified for non-aged films containing a small amount of the monoclinic-like phase. The values of αortho (IR) are larger than αortho (i), the difference ranging between 0.12 and 0.43. The difference is a measure of the short-range order. αortho (IR) can reach 0.73 for the S-films. The stability of the short-range order phase is investigated. The sample is also analyzed using the trace of slow calorimetry. The difference between αortho by DSC and by slow calorimetry is a measure of strainable order. During aging, the variation in the phase content is large for the noncrystalline phases (in content and frequency) and small for the orthorhombic. The increase of the monoclinic-like phase during aging suggests that it is a precursor of the more stable orthorhombic organization. The quantification of two noncrystalline phases on fresh and aged films clarifies some ambiguity found in the literature about the monoclinic-like phase and the localization of bands in the rocking region for sample characterization. Analysis of other regions of the spectrum is needed to confirm the present results. Key words: low-density PE, phase content, FTIR, network phase, slow calorimetry.