Bivalirudin started during emergency transport for primary PCI.

BACKGROUND: Bivalirudin, as compared with heparin and glycoprotein IIb/IIIa inhibitors, has been shown to reduce rates of bleeding and death in patients undergoing primary percutaneous coronary intervention (PCI). Whether these benefits persist in contemporary practice characterized by prehospital initiation of treatment, optional use of glycoprotein IIb/IIIa inhibitors and novel P2Y12 inhibitors, and radial-artery PCI access use is unknown. METHODS: We randomly assigned 2218 patients with ST-segment elevation myocardial infarction (STEMI) who were being transported for primary PCI to receive either bivalirudin or unfractionated or low-molecular-weight heparin with optional glycoprotein IIb/IIIa inhibitors (control group). The primary outcome at 30 days was a composite of death or major bleeding not associated with coronary-artery bypass grafting (CABG), and the principal secondary outcome was a composite of death, reinfarction, or non-CABG major bleeding. RESULTS: Bivalirudin, as compared with the control intervention, reduced the risk of the primary outcome (5.1% vs. 8.5%; relative risk, 0.60; 95% confidence interval [CI], 0.43 to 0.82; P=0.001) and the principal secondary outcome (6.6% vs. 9.2%; relative risk, 0.72; 95% CI, 0.54 to 0.96; P=0.02). Bivalirudin also reduced the risk of major bleeding (2.6% vs. 6.0%; relative risk, 0.43; 95% CI, 0.28 to 0.66; P<0.001). The risk of acute stent thrombosis was higher with bivalirudin (1.1% vs. 0.2%; relative risk, 6.11; 95% CI, 1.37 to 27.24; P=0.007). There was no significant difference in rates of death (2.9% vs. 3.1%) or reinfarction (1.7% vs. 0.9%). Results were consistent across subgroups of patients. CONCLUSIONS: Bivalirudin, started during transport for primary PCI, improved 30-day clinical outcomes with a reduction in major bleeding but with an increase in acute stent thrombosis. (Funded by the Medicines Company; EUROMAX ClinicalTrials.gov number, NCT01087723.).

Design and methods of European Ambulance Acute Coronary Syndrome Angiography Trial (EUROMAX): an international randomized open-label ambulance trial of bivalirudin versus standard-of-care anticoagulation in patients with acute ST-segment-elevation myocardial infarction transferred for primary percutaneous coronary intervention.

BACKGROUND: In patients with ST-segment elevation myocardial infarction (STEMI) triaged to primary percutaneous coronary intervention (PCI), anticoagulation often is initiated in the ambulance during transfer to a PCI site. In this prehospital setting, bivalirudin has not been compared with standard-of-care anticoagulation. In addition, it has not been tested in conjunction with the newer P2Y12 inhibitors prasugrel or ticagrelor. DESIGN: EUROMAX is a randomized, international, prospective, open-label ambulance trial comparing bivalirudin with standard-of-care anticoagulation with or without glycoprotein IIb/IIIa inhibitors in 2200 patients with STEMI and intended for primary percutaneous coronary intervention (PCI), presenting either via ambulance or to centers where PCI is not performed. Patients will receive either bivalirudin given as a 0.75 mg/kg bolus followed immediately by a 1.75-mg/kg per hour infusion for ≥30 minutes prior to primary PCI and continued for ≥4 hours after the end of the procedure at the reduced dose of 0.25 mg/kg per hour, or heparins at guideline-recommended doses, with or without routine or bailout glycoprotein IIb/IIIa inhibitor treatment according to local practice. The primary end point is the composite incidence of death or non-coronary-artery-bypass-graft related protocol major bleeding at 30 days by intention to treat. CONCLUSION: The EUROMAX trial will test whether bivalirudin started in the ambulance and continued for 4 hours after primary PCI improves clinical outcomes compared with guideline-recommended standard-of-care heparin-based regimens, and will also provide information on the combination of bivalirudin with prasugrel or ticagrelor.

Heterologous expression and topography of the main intrinsic protein (MIP) from rat lens.

Wild type rat lens main intrinsic protein (MIP) and MIP mutated (F73I, F75L) to resemble the glycerol facilitator of Escherichia coli in the region of the NPA1 box were used to investigate the topology of MIP in the membrane of Spodoptera frugiperda (Sf21) cells using the baculovirus expression system and expression in mouse erythroid leukaemia cells (MEL C88). Differential fixation for staining was used, with paraformaldehyde for externally exposed antigenic sites, and acetone for both externally and internally exposed protein antigenic sites. Immunofluorescence using antibodies to synthetic MIP peptides showed that wild type MIP had a six transmembrane topography. The N- and C-termini were intracellular in both expression systems, and both NPA boxes were found to be extracellular. These results show that residues around the NPA1 box can influence the folding of the MIP in the membrane, and provide structural evidence for the poor water transport properties of MIP, as the NPA boxes lie outside the plane of the membrane.

pH-Dependent channel activity of heterologously-expressed main intrinsic protein (MIP) from rat lens.

Wild-type rat lens main intrinsic protein (MIP) was heterologously expressed in the membrane of Spodoptera frugiperda (Sf21) cells using the baculovirus expression system and in mouse erythroid leukaemia cells (MEL C88). Both MEL and Sf21 cell lines expressing wild-type MIP were investigated for the conductance of ions using a whole cell patch clamp technique. An increase in conductance was seen in both expression systems, particularly on lowering the pH to 6.3. In Sf21 cells, addition of antibodies to the NPA1 box resulted in a reduction of current flow. These results suggest that MIP has pH-dependent ion channel activity, which involves the NPA1 box domain.