Comparison of catheter-directed thrombolysis with and without percutaneous mechanical thrombectomy for subacute iliofemoral deep vein thrombosis

OBJECTIVE

To evaluate and compare the treatment efficacy and safety between catheter-directed thrombolysis monotherapy and catheter-directed thrombolysis combined with percutaneous mechanical thrombectomy for patients with subacute iliofemoral deep vein thrombosis.

METHODS

We conducted a retrospective analysis of a total of 74 subacute iliofemoral deep vein thrombosis patients who underwent catheter-directed thrombolysis with and without percutaneous mechanical thrombectomy. Patients treated with catheter-directed thrombolysis combined with percutaneous mechanical thrombectomy (percutaneous mechanical thrombectomy group, n = 30) or catheter-directed thrombolysis monotherapy (catheter-directed thrombolysis group, n = 44) were included. The primary endpoints were the clinical efficacy rate of thrombolysis, primary patency, and the incidence of post-thrombotic syndrome (at 12 months diagnosed according to the original Villalta score criteria. Secondary endpoints were the total urokinase dose, the thrombolysis time, the detumescence rate and complications.

RESULTS

The percentage of successful thrombolysis for percutaneous mechanical thrombectomy group was higher than that for catheter-directed thrombolysis group (P = 0.045). At the 12-month follow-up, there was no difference in the primary patency (P > 0.05) or the incidence of post-thrombotic syndrome (P = 0.36). Percutaneous mechanical thrombectomy group had significant advantages in reducing urokinase doses and thrombolysis times compared with catheter-directed thrombolysis group for patients with thrombus clearance levels II and III (P < 0.05).

CONCLUSION

Catheter-directed thrombolysis combined with percutaneous mechanical thrombectomy performs better in removing vein thrombi, reducing urokinase doses, and shortening thrombolysis times.

Inactivation of surfactant in rat lungs

Although surfactant replacement therapy has dramatically improved the outcome of premature infants with respiratory distress syndrome, approximately 30% of treated infants show a transient or no response. Nonresponse to surfactant replacement therapy may be due to extreme lung immaturity and possibly surfactant inactivation. Surfactant inactivation involves aspecific biophysical events, such as interference with the formation or activity of an alveolar monolayer, and specific interactions with serum proteins, including antibodies, leaking into the alveolar space. As formulations containing surfactant proteins appear to better tolerate serum inactivation, we used an excised rat lung model to compare the susceptibility to serum inactivation of a mixture of synthetic phospholipids selected from surfactant lipid constituents, Exosurf (a protein-free synthetic surfactant), Survanta [containing surfactant proteins B and C (SP-B and -C)], and a porcine surfactant (containing SP-A, -B, and -C). For each of these preparations, we used pressure/volume determinations as an in situ measure of surfactant activity and retested the same preparations after mixing with human serum, a nonspecific surfactant inactivator. Human serum inactivated porcine surfactant to a lesser extent than Survanta, Exosurf, or synthetic phospholipids. Temperature exerted a significant effect on deflation stability, as shown by a greater lung compliance in untreated, normal lungs and a larger improvement in compliance after treating lavaged lungs with synthetic phospholipids at 37 degrees C than at 22 degrees C. We conclude that surfactant containing SP-A, -B, and -C is only moderately susceptible to inactivation with whole serum and may therefore exert a greater clinical response than protein-free surfactants or those containing only SP-B and -C.

Uptake of antioxidants in surfactant liposomes by cultured alveolar type II cells is enhanced by SP-A

Antioxidant delivery may be targeted toward the alveolar epithelium by encapsulating superoxide dismutase (SOD) and catalase in liposomes made from pulmonary surfactant. We studied whether antioxidant-surfactant liposomes increase cellular antioxidant activity in alveolar type II cells and whether this effect is influenced by the presence of surfactant protein A (SP-A). Cu,Zn SOD and catalase were encapsulated in liposomes made from synthetic phospholipids with or without 5% SP-A or from natural cow surfactant. Alveolar type II cells from adult rats were preincubated for 20 h, and liposome mixtures were added for 24 h, followed by measurement of cellular SOD and catalase activities (U/mg DNA). Antioxidant-surfactant liposomes increased alveolar type II cell antioxidant activity sharply. Uptake of SOD/catalase from liposomes with synthetic phospholipids and SP-A was twice that from liposomes without SP-A and did not further improve in the presence of SP-B and -C. Encapsulation of antioxidants diminished the surface activity of the surfactant liposomes, but this feature was absent in the presence of SP-A. These data suggest that: 1) antioxidant-surfactant liposomes augment alveolar type II cell antioxidant activity, 2) liposomal uptake is facilitated by the presence of SP-A, and 3) inhibition of surface activity of surfactant by encapsulated antioxidants can be reversed by SP-A.

Antibodies against synthetic amphipathic helical sequences of surfactant protein SP-B detect a conformational change in the native protein

Synthetic peptides based on the native human sequence of surfactant protein B have been used to generate polyclonal monospecific antibodies against specific segments of the native SP-B protein. Circular dichroism analysis of the synthetic peptides shows they have a dominant helical content in structure promoting environments and tensiometric measurements indicate these peptides lower surface tension at air-water interfaces implying that they contain amphipathic alpha helical motifs. Antibodies directed against the C-terminal segment of SP-B react with the native protein in the oxidized and reduced state. Antibodies directed against the N-terminal sequence of SP-B react with the native protein only in the reduced state suggesting that this domain has a conformation dependent on disulfide bond formation.

Staining properties of bovine low molecular weight hydrophobic surfactant proteins after polyacrylamide gel electrophoresis

Reports describing polyacrylamide gel electrophoresis patterns of bovine hydrophobic surfactant proteins are not consistent. In this study, we found unusual staining characteristics of these proteins that may explain some of these inconsistencies. Low molecular weight surfactant proteins extracted from bronchoalveolar lavage with organic solvent are partially delipidated with Sephadex LH-20 chromatography using chloroform and methanol. Fractions from the first protein peak are dried under nitrogen then subjected to SDS electrophoresis on 20% polyacrylamide gels. Under nonreducing conditions, silver staining identifies 5- and 26-kDa bands, and Coomassie blue identifies 6-, 12-, and 26-kDa bands. When gels are stained with Coomassie blue then silver, the 5- and 26-kDa bands stain with silver and 6- and 12-kDa bands remain stained with Coomassie blue. If gels are first stained with silver then Coomassie blue, similar results occur. We modified the silver staining protocol by treating gels with dithiothreitol or 2-mercaptoethanol after electrophoresis. With this modification, 5-, 6-, 12-, 26-, and also 17-kDa bands are identifiable. Using the modified protocol and restaining gels previously stained with silver, 6-, 12-, and 17-kDa bands that were not identified previously all became visible. In further experiments, protein bands of 6-, 12-, and 26-kDa that were identified by Coomassie blue were electroeluted under nonreducing conditions. After electrophoresis of the eluted 26-kDa protein, bands of 17-, and 26-kDa under nonreducing, and 8-kDa only under reducing conditions, were apparent by using the modified silver protocol.(ABSTRACT TRUNCATED AT 250 WORDS)