Heparin coating of poly(ethylene terephthalate) decreases hydrophobicity, monocyte/leukocyte interaction and tissue interaction.

Woven poly(ethylene terephthalate) (PET) is widely used in implantable medical devices. Upon implantation, fibrinogen interacts with the PET and changes conformation, such that the fibrinogen P2 epitope may become exposed. This allows inflammatory cells to interact with the material. In this study we have coated PET with heparin and show that this decreases PET hydrophobicity and the presence of the fibrinogen P2 epitope on the material surface. In addition, we show that heparin-induced reduction of PET hydrophobicity correlates with decreased exposure of the fibrinogen P2 epitope and reduced adhesion of monocytes. Reduction of PET hydrophobicity was furthermore associated with reduced PMN elastase production and decreased interaction between PET and embryonic chicken tissue. We conclude that the heparin coating-induced decrease in PET hydrophobicity is associated with decreased interaction between PET and inflammatory cells. Independent of this interaction, the hydrophobic nature of the heparin coating is related to tissue interaction as demonstrated by a reduction in adhesion, growth and spreading of tissue on PET. The combination of these properties makes heparin coating a candidate for improving biocompatibility of PET.

Impact of case management by advanced practice nurses in primary care on unplanned hospital admissions: a controlled intervention study.

BACKGROUND: Increasing unplanned hospital admissions disrupt planned health care, lead to additional morbidity and are expensive. A recent review found only weak evidence for case management preventing unplanned admissions, yet case management of older people is being implemented widely in the UK. We aimed to study the effect of advanced practice nurse case management on unplanned medical and geriatric hospital admission rates in patients 50 years and over, and on admission risk in a 'higher risk' sub-group of patients in the UK. METHODS: Case management by advanced practice nurses in NHS primary care practices in the Swansea Local Health Board area, Wales, UK. We conducted a prospective non-randomized controlled intervention study comparing unplanned medical and geriatric patient admissions between five intervention and thirty non-intervention practices during a pre-intervention year and an intervention year. RESULTS: For all lengths of stay, comparing intervention (n = 5) with non-intervention practices (n = 30) from pre-intervention to intervention year, we found that the unplanned medical and geriatric admission rate was significantly lower in the intervention group - adjusted relative risk of 0.909; relative risk reduction 9.1% (95% credible limit 0.840 to 0.984, p = 0.018); absolute risk reduction 0.99 admissions per 100 patients (95% credible limit 0.17 to 1.86, p = 0.018). For lengths of stay of one night or more we observed a stronger effect - adjusted relative risk 0.896; relative risk reduction 10.41% (95%, credible limit 0.820 to 0.979, p = 0.015). Most of the rate reduction was due to a reduction in the number of new admissions but much less so for admissions of lengths of stay of at least one night, compared to all lengths of stay. We did not find a statistically significant effect on re-admission or multiple re-admission rates in 'higher risk' patients previously admitted one or more times - adjusted relative risk of further multiple admissions per previously admitted patient 0.908 (95% credible limit 0.765, 1.077); relative risk reduction 9.3%; adjusted relative risk of total admissions per multiple admitter 0.995 (95% credible limit 0.940, 1.053) relative risk reduction 0.6%. CONCLUSION: Although this study reports a reduction in unplanned admission rates in the intervention practices, this appears to be only in part directly due to nurse case management: most of the reduction did not occur in multipe admitters whom were case managed. Further research is needed to explain this finding, to elucidate how best to target the attention of case managers and to examine the complexity of potential outcomes in terms of the nature and necessity of admissions and most suitable lengths-of-stay in terms of acute care or rehabilittion need.

Case management by nurses in primary care: analysis of 73 'success stories'.

BACKGROUND: There is interest as to whether case management reduces unplanned patient admission to hospital. However, very little is known about how the intervention is delivered and what the most salient outcome measures are. DESIGN: Qualitative study embedded in a wider evaluation. SETTING: Primary health care. METHOD: Analysis of case manager case reports in a service innovation evaluation study. RESULTS: Case management provides home-based care to frail elderly patients using a process of assessment and medication review. This often leads to new diagnoses, to the co-ordination of further care and the tailoring of services to suit the needs of individuals. The benefits reported are complex and relate to improving a patient's quality of life more than the prevention or otherwise of admission to hospital. The type of attention provided by these roles seems to be absent from current NHS arrangements. The role enables time to be spent assessing the individual needs of patients who live at the margins of independent living. CONCLUSION: The case managers describe having the time and the skills to assess a mix of clinical and social problems, and then accessing the correct networks to help elderly people with multiple illnesses navigate a complex system of providers. More weight should be given to the ability of this intervention to result in improved quality of life for patients, and to the investigation of costs and benefits.

Ongoing foreign body reaction to subcutaneous implanted (heparin) modified Dacron in rats.

Dacron-containing heart valve repair devices trigger chronic inflammation characterized by the presence of activated macrophages, foreign body giant cells, and capsule formation. Upon blood contact, proinflammatory proteins adsorb to the material and provide a substrate for monocyte binding and differentiation. Various heparin-coated polymers have been shown to reduce adsorption of proinflammatory proteins in vitro and in vivo. In this study, the effect of knitted, heparin-coated Dacron on the foreign body reaction was tested subcutaneously in rats. We hypothesized that the anti-inflammatory effect of heparin would reduce monocyte recruitment and differentiation and therefore limit the inflammatory reaction. An ongoing foreign body reaction, characterized by the presence of foreign body giant cells and high vascularization, was observed in uncoated as well as (heparin-)coated Dacron at up to 180 days of implantation. Also, a thin capsule was formed around each material up to this time. In conclusion, although heparin coatings might have an effect on the acute inflammatory response, we were not able to show a difference between heparin-coated and uncoated Dacron after 180 days' implantation in rats. Further research needs to be conducted to assess the difference in proinflammatory protein adsorption between the tested materials and the effect this has on the long-term foreign body reaction.