P5522ST elevation myocardial infarction networks: relationship of hub-spoke distance with transfer time and clinical outcomes in rescue PCI

Background

In the establishment of ST elevation myocardial infarction (STEMI) systems of care, transfer times between primary care units (PCU) and the cardiac catheterization lab (CCL) are pillars to therapeutic success. Objective: To analyze the relationship between PCU-CCL distance with transport time and main clinical outcomes in STEMI patients (p) treated with pharmaco-invasive therapy (PIT) and referred for rescue PCI after failed fibrinolysis.

Methods

Between January 2010 and December 2018, of the 2241 patients who received tenecteplase in PCU inserted in a large city STEMI network, 801 (35.7%) evolved without reperfusion criteria after 90 minutes (persistence of chest pain, less than 50% reduction on ST elevation or hemodynamic instability), being urgently transferred to the CCL. The PCU were divided according to the distance to the tertiary center in Group 1: between 5 and 9km (N=208p), Group 2: between 16 and 18km (N=315p) and Group 3: between 22 and 30km=266p). Considering an alpha of 0.05, sample size n=801 and an effect size of 0.11, a power of 0.80 was obtained.

Results

The groups were comparable for baseline features (Table 1). Group 2 (intermediate distances) had the highest median transport time (G1 260 interquartile 145–437 min vs G2 355 interquartile 206–573 min vs G3 241 interquartile 125–418 min; p<0.01 for G2). There were no differences between the groups regarding cardiogenic shock (G1 24.5% vs G2 23.3% vs G3 24.1%, p=0.9) or in-hospital death (G1 17.4% vs G2 12.3% vs G3 13.0%, p=0.2).

Table 1. Group's baseline features G1: Short distances G2: Intermediate distances G3: Long distances p value (5–9 km) N=208 (16–18 km) N=315 (22–30 km) N=266 Age (median) 57.5 (51–64) 57 (49–66) 59 (52–67) 0.27 Female 29.7% 28.3% 35.1% 0.19 Hypertension 67.3% 60.9% 64.4% 0.31 Diabetes 37.0% 32.1% 37.8% 0.30 Renal failure 10.3% 9.7% 6.3% 0.21 Anterior STEMI 56.1% 58.4% 62.4% 0.36 Pain-to-needle time (median min) 197.5 (137–330) 195 (120–295) 195 (125–345) 0.38

Conclusion

In STEMI patients with failed fibrinolysis treated with pharmaco-invasive therapy, the PCU-CCL distance was not related to transfer time or to outcomes of in-hospital death and cardiogenic shock. The longer transport time of hospitals located at intermediate distance can possibly reflect local logistical difficulties and are not due to hub-spoke distance. Continuous improvement in structuring and coordination of public STEMI networks is aimed.

Downmodulation of CD18 and CD86 on macrophages and VLA-4 on lymphocytes in experimental tuberculosis

Development and evaluation of new vaccines and immunotherapy against tuberculosis demand a better understanding of the immune mechanisms in this disease. Costimulatory signals and intercellular contact seem to be pivotal in determining whether recognition of antigen by T cells leads to activation or anergy. In this paper, we show that virulent M. tuberculosis H37Rv downmodulates the ex vivo expression of CD18 and CD86 on peritoneal macrophages and VLA-4 on lymphocytes but does not disturb the in vitro production of interleukin (IL)-12 and interferon (IFN)-gamma after intraperitoneal infection. In addition, splenocytes from infected mice produce IL-10, while the expression of cell surface receptors is unchanged. The interplay among IL-12, IFN-gamma and IL-10 in vivo and the downmodulation of cell-surface receptors during the infection at the inflammatory site may contribute to the explanation of the maintenance of infection.

Role of trehalose dimycolate in recruitment of cells and modulation of production of cytokines and NO in tuberculosis

Mice treated with viable Mycobacterium tuberculosis with no glycolipid trehalose dimycolate (TDM) on the outer cell wall (delipidated M. tuberculosis) by intraperitoneal or intratracheal inoculation presented an intense recruitment of polymorphonuclear cells into the peritoneal cavity and an acute inflammatory reaction in the lungs, respectively. In addition, lung lesions were resolved around the 32nd day after intratracheal inoculation. TDM-loaded biodegradable poly-DL-lactide-coglycolide microspheres as well as TDM-coated charcoal particles induced an intense inflammatory reaction. In addition, high levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), IL-12, IL-10, gamma interferon (IFN-gamma), and IL-4 production were detected in lung cells, and nitric oxide (NO) production was high in culture supernatants of bronchoalveolar lavage cells. These in vivo data were confirmed by in vitro experiments using peritoneal macrophages cultured in the presence of TDM adsorbed onto coverslips. High levels of IFN-gamma, IL-6, TNF-alpha, IL-12, IL-10, and NO were detected in the culture supernatants. Our results suggest that TDM contributes to persistence of infection through production of cytokines, which are important for the recruitment of inflammatory cells and maintenance of a granulomatous reaction. In addition, our findings are important for a better understanding of the immunostimulatory activity of TDM and its possible use as an adjuvant in experiments using DNA vaccine or gene therapy against tuberculosis.

Characterization of the memory/activated T cells that mediate the long-lived host response against tuberculosis after bacillus Calmette-Guérin or DNA vaccination

The memory/activated T cells, which mediate the long-lived host response against tuberculosis, in mice immunized with either bacillus Calmette-Guérin (BCG) or mycobacterium heat-shock protein 65 (hsp 65) antigen expressed from plasmid DNA (DNA-hsp 65), were characterized. Protection against Mycobacterium tuberculosis challenge by DNA-hsp 65 vaccination was associated with the presence of lymph node T-cell populations in which CD8+/CD44hi interferon-gamma (IFN-gamma)-producing/cytotoxic cells were prominent even after 8 or 15 months of plasmid DNA-mediated immunizations, whereas after BCG vaccination the majority were CD4+/CD44lo IFN-gamma-producing T cells. When the cells were separated into CD4+CD8- and CD8+CD4- and then into CD44hi and CD44lo types, CD44lo cells were essentially unable to transfer protection in adoptive transfer experiments, the most protective CD44hi cells were CD8+CD4- and those from DNA-vaccinated mice were much more protective than those from BCG-immunized mice. The frequency of protective T cells and the level of protection were increased up to 8 months and decreased after 15 months following DNA or BCG immunizations.

Therapy of tuberculosis in mice by DNA vaccination

Mycobacterium tuberculosis continues to kill about 3 million people every year, more than any other single infectious agent. This is attributed primarily to an inadequate immune response towards infecting bacteria, which suffer growth inhibition rather than death and subsequently multiply catastrophically. Although the bacillus Calmette-Guerin (BCG) vaccine is widely used, it has major limitations as a preventative measure. In addition, effective treatment requires that patients take large doses of antibacterial drug combinations for at least 6 months after diagnosis, which is difficult to achieve in many parts of the world and is further restricted by the emergence of multidrug-resistant strains of M. tuberculosis. In these circumstances, immunotherapy to boost the efficiency of the immune system in infected patients could be a valuable adjunct to antibacterial chemotherapy. Here we show in mice that DNA vaccines, initially designed to prevent infection, can also have a pronounced therapeutic action. In heavily infected mice, DNA vaccinations can switch the immune response from one that is relatively inefficient and gives bacterial stasis to one that kills bacteria. Application of such immunotherapy in conjunction with conventional chemotherapeutic antibacterial drugs might result in faster or more certain cure of the disease in humans.

DNA encoding individual mycobacterial antigens protects mice against tuberculosis

Over the last few years, some of our experiments in which mycobacterial antigens were presented to the immune system as if they were viral antigens have had a significant impact on our understanding of protective immunity against tuberculosis. They have also markedly enhanced the prospects for new vaccines. We now know that individual mycobacterial protein antigens can confer protection equal to that from live BCG vaccine in mice. A critical determinant of the outcome of immunization appears to be the degree to which antigen-specific cytotoxic T cells are generated by the immune response. Our most recent studies indicate that DNA vaccination is an effective way to establish long-lasting cytotoxic T cell memory and protection against tuberculosis.

[Accidental tetanus: clinical and epidemiological profile of inpatients at a university hospital]

INTRODUCTION

Notwithstanding its substantial decline over the last two decades, acquired tetanus is still a serious health problem in most developing countries. Epidemiological transition is often cited as an explanation for this decline, the increase in vaccination coverage of children being the most obvious cause. Few studies have looked carefully at the current epidemiological patterns of acquired tetanus in developing countries.

METHODOLOGY

A descriptive, retrospective (series of cases). An acute care 400 - bed university referral hospital situated in a densely populated and highly urbanized area in Southeastern Brazil (Campinas, SP). Patient records the data-base analysed were from the Epidemiological Surveillance Unit of the hospital.

RESULTS

In the 57 month period from January 1989 to March 1996 fifty-three patients were admitted with a diagnosis of acquired tetanus. Fifty patients had clinical confirmation, 3 were otherwise diagnosed. Thirty-two (64%) were male and 18 (36%) female. Fourteen (28%) were from rural areas and 36 (72%) from urban. Mean age was 47.6 years, with a median of 49.5. Of the rural patients, 42.85% were under 30 years and 21.42% were over 50, mean age was 36.21 with a median of 34.5. Fewer urban patients were under 30 (13.88%) than over 50 (58.33%), mean age was 52.19 with a median of 54.5. Trismus was the most frequent (92.0%) clinical sign on admittance, followed by abdominal muscular rigidity (84.0%). Treatment measures were uniform and included tetanus immune globulin, antibiotics, surgical debridement of the wound when feasible, diazepan or curare depending on the intensity of spasms. In the second half of the study period, penicillin was replaced by metronidazol. Overall case fatality rate was 20%, in patients that had to receive curare, it was 60%. Hospitalization exceeded 21 days in 56% (28) of the cases, only 10% (5) had a hospital stay of less than 7 days.

CONCLUSION

A high proportion of patients were from rural areas, despite an urbanization rate of more than 90%. In the Campinas region there are two different epidemiological patterns of acquired tetanus: a rural pattern, with a higher proportion of younger patients, determined by an inadequate immunization rate and an urban pattern, similar to that found in industrialized countries, with a higher proportion of older patients.

RECOMMENDATIONS

There is an obvious need to immunize older individuals in urban areas and young adults in rural areas. The elimination of acquired tetanus will only be achieved with a wider and more intensive adult vaccination program.

Identification and characterization of protective T cells in hsp65 DNA-vaccinated and Mycobacterium tuberculosis-infected mice

Immunization by intramuscular injection of plasmid DNA expressing mycobacterial 65-kDa heat shock protein (hsp65) protects mice against challenge with virulent Mycobacterium tuberculosis H37Rv. During infection or after immunization, CD4+/CD8- and CD8+/CD4- hsp65-reactive T cells increased equally in spleens. During infection, the majority of these cells were weakly CD44 positive (CD44(lo)) and produced interleukin 4 (IL-4) whereas after immunization the majority were highly CD44 positive (CD44(hi)) and produced gamma interferon (IFN-gamma). In adoptive transfer of protection to naive mice, the total CD8+/CD4- cell population purified from spleens of immunized mice was more protective than that from infected mice. When the cells were separated into CD4+/CD8- and CD8+/CD4- types and then into CD44(hi) and CD44(lo) types, CD44(lo) cells were essentially unable to transfer protection, the most protective CD44(hi) cells were CD8+/CD4-, and those from immunized mice were much more protective than those from infected mice. Thus, whereas the CD44(lo) IL-4-producing phenotype prevailed during infection, protection was associated with the CD8+/CD44(hi) IFN-gamma-producing phenotype that predominated after immunization. This conclusion was confirmed and extended by analysis of 16 hsp65-reactive T-cell clones from infected mice and 16 from immunized mice; the most protective clones, in addition, displayed antigen-specific cytotoxicity.

Protection against tuberculosis by bone marrow cells expressing mycobacterial hsp65

Although mice acquire only a slight degree of protection against tuberculosis by immunization with Mycobacterium leprae (M. leprae) hsp65 in incomplete Freund's adjuvant, protection is substantial following immunization by injection with J774 macrophage-like tumour cells that express the protein from the mycobacterial gene via a retroviral vector. We here took the same vector, used it to transfect the gene into normal murine bone marrow cells in vitro, and then used the transfected cells to reconstitute haematopoiesis in lethally irradiated mice. Bone marrow-cell clonal expansion and production of the protein in vivo resulted in specific delayed-type hypersensitivity and protection against challenge with Mycobacterium tuberculosis (M. tuberculosis) in about half of recipients. Counts of live bacteria in liver at 3 weeks were fivefold lower in delayed-type hypersensitivity (DTH)-positive than in DTH-negative mice. Other mice acquired neither DTH nor protection despite the presence of the protein in peripheral blood.