Flexible bronchoscopic implantation of Accuflex and Strecker stents in malignant bronchial stenoses

Silicone and metal stents are available for the treatment of malignant bronchial stenoses. This project sought to compare the self-expanding nitinol Accuflex stent (Boston Scientific Corp; Watertown, Mass) with the passively expandable tantalum Strecker stent (Boston Scientific Corp; Watertown, Mass), both implanted by flexible bronchoscopy under local anesthesia and sedation. In 51 patients with malignant bronchial stenosis, 14 nitinol and 51 tantalum stents were used and stenoses of 75 to 100% were treated. The intervention was successful in all but one patient, a mean patency of 93% was achieved. In the follow-up period, the probability of survival was significantly lower in patients with total bronchus occlusion than in patients with stenotic alteration (44 vs 109 days; p < 0.05). In 10 patients, lung function analysis after stent implantation revealed a significant increase in PaO2 (65 vs 71 mm Hg; p < 0.01), inspiratory vital capacity (2.5 vs 2.7 L; p < 0.05), and FEV1 (1.8 vs 2.0 L; p < 0.05). Mucus retention was the main (39%) adverse factor in the early phase after stent implantation, whereas tumor penetration became the most frequent problem (67%) in the later phase. Recanalizing interventions were necessary in 18% of the cases in which tumor penetration occurred. Stent distortion occurred in 12 patients with Strecker and in none with Accuflex stents. In comparison to the Strecker stent, the self-expanding Accuflex stent is preferable owing to its excellent flexibility and faster delivery system. Both types of stents could be sufficiently deployed within the lesions and allowed for highly precise positioning. Furthermore, no general anesthesia was required. The fiber-bronchoscopy mode of implantation under sedation is very efficient even for tumor patients with severe impairment of their physical and respiratory condition.     

Characterization of paroxysmal and persistent atrial fibrillation in the human left atrium during initiation and sustained episodes

INTRODUCTION: Atrial fibrillation (AF) in the left atrium (LA) is poorly defined in terms of regional differences in the degree of organization, characteristics of paroxysmal and persistent variants, and electrophysiologic events that develop at the onset of episodes. METHODS AND RESULTS: The study population consisted of 21 patients (15 men and 6 women; mean age 58+/-9.4 years) with paroxysmal (10 patients) or persistent (11 patients) AF. Mapping of the LA during sustained episodes and the onset of AF was performed with a 64-electrode basket catheter. At the onset of AF, repetitive beats starting with atrial premature complexes and ending with generation of the earliest fibrillatory activity were defined as intermediary rhythm. Patients with paroxysmal AF had longer AF cycle lengths and more pronounced regional differences than patients with persistent AF. In total, AF cycle lengths in the LA in patients with persistent AF were 20% shorter than in patients with paroxysmal AF. Initiation of AF was preceded by an intermediary rhythm of 5.5+/-2.5 cycles (6.3+/-2.7 cycles in paroxysmal AF vs 4.2+/-1.0 cycles in persistent AF; P = 0.026). At the onset of AF, the earliest generators of fibrillatory activity were located more frequently in the posterior wall of the LA. CONCLUSION: AF in the LA displays substantial regional differences in terms of AF cycle lengths and degree of organization. Patients with persistent AF have shorter cycle lengths and a higher degree of disorganized activity than patients with paroxysmal AF. Intermediary rhythms play an important role in initiation of AF via activation of generator regions in the LA.     

Specificity of human immunodeficiency virus (LAV/HTLV-III)-reactive antibodies in African sera from southeastern Tanzania

The prevalence of antibodies to human immunodeficiency virus (HIV = LAV/HTLV-III) in a rural population from the Ifakara area in southeastern Tanzania was investigated. Sera from 286 individuals collected from 1982 to 1984 in connection with a study on liver disorders were tested by an ELISA. Fifty-two (18.2%) of the sera were found positive. While the positives were largely confirmed by one commercial ELISA, they were completely negative by two others. Confirmatory testing by Western blot and competition Western blot showed that the reactivity detected by more sensitive of these assays was largely due to IgG antibodies binding to the HIV core (gag) proteins p17, its precursor p55 and, in some cases, p24. These tests also indicated, however, that the reactive antibodies could not have been elicited by HIV, but possibly by an unknown retrovirus or another cross-reactive agent. Thus, by 1984, the area investigated was largely free of HIV infection, but a significant proportion of its population may harbor another retrovirus of unknown pathogenicity.