Reuse of balloon catheters for coronary angioplasty: a potential cost-saving strategy?

OBJECTIVES: This study was designed to determine the effectiveness, safety and costs associated with reuse of angioplasty catheters and to compare these results with those of a contemporary center that employed a single-use strategy. BACKGROUND: Coronary angioplasty is an important but expensive procedure. To overcome the financial constraints of the Canadian health care system, reuse of angioplasty catheters is routinely practiced in some institutions. METHODS: In a prospective observational study, data forms were completed after each angioplasty procedure and before patient discharge over a 10-month period. RESULTS: A total of 693 patients underwent coronary angioplasty in the two centers. Clinical and lesion characteristics were similar except for a higher incidence of unstable angina at the reuse center (p < 0.005). The angiographic success rate was identical (88%) at both centers. The reuse center utilized more balloon catheters/lesion (mean +/- SD 2.4 +/- 1.5 vs. 1.2 +/- 0.5, p < 0.00001) and had a higher incidence of initial balloon failure (10.2% vs. 3.3%, p < 0.0001). Significant prolongation of the procedure time (81 +/- 41 vs. 68 +/- 32 min, p < 0.0001) and increased volume of contrast medium (201 +/- 86 vs. 165 +/- 61 ml, p < 0.0001) were seen in the reuse center. A higher rate of adverse clinical events (7.8% vs. 3.8%, p < 0.025) was observed in the reuse center, especially in patients with unstable angina. CONCLUSIONS: The reuse strategy was associated with a higher rate of adverse events, prolonged procedure time and increased use of contrast medium, especially in lesions that were not crossed by the initial balloon and in patients with unstable angina. Whether these differences are related to the reuse strategy or to differences in patient groups cannot be ascertained by this observational study. A multicenter randomized trial is required to further assess the safety and the cost/benefit ratio of this strategy.

Alpha-delta sleep in patients with a chief complaint of chronic fatigue.

Our prospective, standardized cohort study was designed to assess the presence of alpha wave intrusions during non-rapid eye movement sleep (alpha-delta sleep) and its relationship to fibromyalgia, major depression, and chronic fatigue syndrome (CFS) in patients with a chief complaint of chronic fatigue. The study group comprised 30 consecutive patients seen at a university hospital referral clinic for evaluation of chronic fatigue. All patients had nocturnal polysomnography, dolorimetric tender point assessment for fibromyalgia, a comprehensive history, physical, and laboratory evaluation, and a structured psychiatric interview. Alpha-delta sleep was identified in 8 of the 30 patients (26%), major depression in 20 (67%), CFS in 15 (50%), and fibromyalgia in 4 (13%). Ten of the 30 patients (33%) had a primary sleep disorder (sleep apnea, periodic limb movements, or narcolepsy). Alpha-delta sleep was not significantly correlated with fibromyalgia, CFS, major depression, or primary sleep disorders, but was significantly more common among patients who had chronic fatigue without major depression. We conclude that primary sleep disorders are relatively common among patients with chronic fatigue and must be diligently sought and treated. Alpha-delta sleep is not a marker of fibromyalgia or CFS, but may contribute to the illness of nondepressed patients with these conditions.

Treatment outcome of sleep apnea.

Two hundred one patients diagnosed as having obstructive sleep apnea (OSA) were interviewed 12-24 months after their evaluation regarding those daytime symptoms associated with sleep apnea: sleepiness, fatigue, impaired memory, and snoring. Continuous positive airway pressure (CPAP) was the treatment most often used by severe sleep apnea patients, and this improved daytime alertness in 84% of the patients. Patients with moderate obstructive sleep apnea often had surgery which led to 85% reporting improved daytime alertness. Patients with mild obstructive sleep apnea usually were treated with weight loss or changing sleep position and also improved 64% and 66%. Patients who declined or failed treatment did not improve. Guidelines for the treatment of sleep apnea are suggested.

Sleep and apnea in the elderly: reliability and validity of 24-hour recordings in the home.

Two studies investigated the reliability and validity of measures of sleep and apnea using the home sleep monitoring system (HMS), which requires no instrumentation of the subject. From a pressure-sensitive pad on the subject's bed, signals from respiration and motility are recorded. These are scored for sleep and the occurrence of apneas, and the following measures are obtained: time in bed, total sleep time, number of awakenings from sleep, waking after sleep onset, sleep efficiency, and number of apneas. Overnight recordings of 14 adults were made concurrently with polysomnographic recordings in the New Haven Sleep Disorders Center. Significant agreement was found for each sleep measure and the apnea index. Four weekly 24-h recordings were made of eight elderly women, aged 62 to 90, in the home. There were significant individual differences and measurement reliability for each sleep measure and number of apneas. Some of the elderly showed highly episodic sleep patterns; and three of them showed high and variable apneas over the four weeks. These studies indicate the potential of the HMS for characterizing sleep in the elderly from nonintrusive, naturalistic observations in the home.

Results for two children using a multiple-electrode intracochlear implant.

Assessments in speech perception, speech production, and language skills were conducted on two children, 5 and 10 years old at the time of surgery, using the Nucleus multiple-electrode cochlear implant. Data were collected pre- and post-operatively to measure changes in performance over time. For closed-set speech perception tests in the audition alone condition, post-operative performance was generally better than pre-operative performance and performance improved post-operatively for both patients. In closed-set vowel and consonant identification and open-set sentence perception for the older patient, post-operative improvements from the vision alone to the auditory-visual condition were recorded and performance improved post-operatively in both conditions. In all measures of speech production for both patients, post-operative scores were higher than pre-operative scores and performance improved post-operatively. In language skills, post-operative scores were higher than pre-operative scores and scores improved post-operatively in all measures for both patients.

Neuropsychological dysfunction in sleep apnea.

To evaluate the effect of intermittent hypoxemia on neuropsychological functioning, neuropsychological tests were administered to 14 sleep apnea patients, a control group of 10 patients with other disorders of excessive somnolence, and another control group of 14 healthy volunteers. The sleep disorder groups were matched on two measures of sleepiness. It was found that sleep apnea patients performed significantly worse than both controls on 7 of 14 neuropsychological measures and on a rating of global neuropsychological impairment. The overall level of performance reflected only moderate impairment. Within the sleep apnea group, hypoxemia severity was significantly correlated with deficits on measures of motor and perceptual-organizational ability.

Antigenic mimicry of mammalian intermediate filaments by mycoplasmas.

A murine monoclonal antibody raised against Mycoplasma hyorhinis specifically reacted by indirect immunofluorescence with mammalian intermediate filaments. The antibody recognized a related epitope on a 74,000-molecular-weight protein of M. hyorhinis and on components of similar size from other pathogenic mycoplasmas. This defines a shared antigenic structure of interest in autoantibody development during mycoplasmal diseases.

Mycoplasma hyorhinis GDL surface protein antigen p120 defined by monoclonal antibody.

Four antigens of Mycoplasma hyorhinis GDL were defined by murine monoclonal antibodies. Components of broth-grown mycoplasmas were separated under reducing conditions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and subsequent protein blots were stained with individual antibodies. Each antibody reacted with a distinct component with relative molecular weights of 120,000, 73,000, 51,000, and 38,000, respectively (termed p120, p73, p51, and p38). Trypsin treatment of protein blots specifically abrogated binding of antibodies, suggesting that the epitopes recognized were associated with proteins. By using indirect immunofluorescence and immunoferritin techniques, mycoplasmas colonizing the surface of chronically infected BW5147 murine T-lymphoblastoid cells were selectively stained with antibody to p120, indicating the localization of the corresponding epitope at the mycoplasma surface. Protein blots of mycoplasmas derived from BW5147 cell cultures were stained with antibody to p120, revealing a component identical to that observed with broth-grown organisms. These results establish the identity of a surface protein antigen of M. hyorhinis GDL expressed at the surface of organisms during their colonization of host cells.

Monoclonal antibodies to Mycoplasma hyorhinis surface antigens: tools for analyzing mycoplasma-lymphoid cell interactions.

A library has been constructed of approximately 50 monoclonal antibodies that recognize antigens of Mycoplasma hyorhinis. Characteristics of six antibodies are discussed. Each reacts with a discrete determinant borne on a protein-containing molecule of distinct molecular size. Three of these respective antigens are expressed at the surface of mycoplasmas colonizing lymphoblastoid cells in culture. Of these three surface antigens, two are selectively expressed on strain GDL but not on strain BTS-7 of M. hyorhinis, thus defining strain-restricted immunological specificities within these species. One monoclonal antibody of the IgM class (mu, kappa) mediated marked complement-dependent growth inhibition of M. hyorhinis in broth culture. These monoclonal reagents should facilitate analysis of mycoplasma surface architecture, and the molecular interactions of these organisms with the host cell surface.

Comparison of cAMP-dependent protein kinase in normal and Rous sarcoma virus transformed chick embryo fibroblasts.

cAMP-dependent protein kinase was compared in normal and Rous Sarcoma Virus transformed chicken embryo fibroblasts. Total cAMP binding activity and cAMP-dependent histone kinase activity were unaltered by RSV transformation. The apparent Km for activation of histone kinase activity by cAMP was 35 nM in both normal and transformed cells. Using 8-N3-cAMP photoaffinity labeling, normal and transformed cells were also found to contain equal quantities of a single 42,000 Mr regulatory sub-unit isoenzyme of A-kinase. This isoenzyme corresponded to the lower molecular weight isoenzyme of the two enzymes found in normal chicken skeletal muscle. Both avian isoenzymes were about 4,000 Mr smaller than the corresponding bovine type I and type II regulatory subunits. Rous Sarcoma Virus transformation does not directly alter the amount or activity of cAMP-dependent protein kinase.

Kinetics of cAMP inhibition of DNA synthesis in bovine adrenocortical cells.

cAMP-treated bovine adrenocortical cells are arrested in the G1 phase of the cell cycle. Removal of serum also arrests bovine adrenocortical cells in G1. In the presence of cAMP, serum and fibroblast growth factor stimulate increases in medium cell volume, but DNA synthesis is not initiated. Under these conditions cAMP increases steroidogenic capacity 7- to 10-fold as assessed by metabolism of pregnenolone to fluorogenic steroids. When the kinetics of entry of cells into S phase are quantitated, serum- and FGF-treated cells initiate DNA synthesis at an exponential rate after a 12-h lag. In contrast when cAMP is removed, cells immediately initiate DNA synthesis without a lag at a similar exponential rate (6.3 and 5.3% of the cells entering S/h). In the presence of growth factors, cAMP-treated bovine adrenocortical cells are thus hypertrophied with increased steroidogenic capacity, but are reversibly arrested at the G1/S boundary. These findings suggest that cAMP arrests cell replication by mechanisms distinct from those of serum deprivation.