Ability of troponin I to predict cardiac events in patients admitted from the emergency department.

OBJECTIVES: We sought to determine the predictive ability of troponin I (TnI) in a heterogeneous group of patients with chest pain admitted from the emergency department (ED) for exclusion of myocardial infarction (MI). BACKGROUND: Previous studies in high-risk patients demonstrated that troponin elevations are associated with increased cardiac events. Little information is available on its predictive ability in more heterogeneous, lower risk patients. METHODS: Consecutive patients admitted from the ED for possible MI underwent serial myocardial marker sampling of TnI and creatine kinase, CK-MB over an 8-h period. Patients with ST segment elevation were excluded. End points included MI, death, significant complications (e.g., cardiac or respiratory arrest, intra-aortic balloon pump, pulmonary artery catheter or pacemaker placement, revascularization or inotropic infusion) and significant disease. RESULTS: Events occurred in 513 (27%) of the 1,929 patients evaluated: MI in 175 (9.1%) and death in 34 (1.8%); an additional 248 patients (13%) without MI had complications, and 323 (17%) without MI had significant disease. Sensitivity of TnI for MI was high (96%). Patients without MI who were TnI-positive were more likely to have complications (43% vs. 12%) or significant disease (41% vs. 17%) as compared with those who were TnI-negative; however, the sensitivity of TnI for these two end points was low (14% and 21%, respectively). Predictive values were unchanged after excluding patients with ischemic electrocardiograms. CONCLUSIONS: Troponin I had a high sensitivity for MI when used as part of a rapid rule-in protocol; however, the sensitivity for other end points was low. Use of TnI alone failed to identify the majority of patients who had either significant disease or complications.

Peroxo heteroligand vanadates(V): synthesis, spectra-structure relationships, and stability toward decomposition.

Effect of heteroligands (L) on the properties of vanadium peroxides was investigated by preparing a number of peroxovanadium complexes, which were characterized by analysis, IR, UV/V and NMR spectra. X-ray structures for some were obtained. The vanadates(V) contain the cation M(I) = Na, K, NH4, Rb or Cs. Diperoxo complexes include M(I)[VO(O2)2 L], where L = dipyridyl, o-phenanthroline; M(I)3[VO(O2)2(C2O4)]; K2[(nicotinic acid)[VO(O2)2]2]H2O;M(I)4[O[VO(O2)2]2cystine]2H2O; H4[O[VO(O2)2(adenine)2)2]2H2O; and K2H2[O[VO(O2)2(adenosine)]2] 2H2O. Monoperoxo vanadates(V) correspond to the formula M(I)2[VO(O2)L]2 for L = citrate and malate; M(I)2[VO(O2)L] for L = nitrilotriacetate; M(I)[VO(O2)L] for L = iminodiacetate, tartrate and EDTA; and [HVO2(O2)(adenosine)]2H2O. Syntheses of these heteroligand peroxovanadium compounds are sensitive to pH, temperature and the concentration of the components. The stability towards decomposition in solid state, mother-liquid and pure water solutions depends upon the heteroligand. Characteristic (V = O) and (O-O) stretching frequency bands in IR can be correlated with the corresponding bond lengths and the [peroxo approximately V(V)] charge transfer bands in UV/V spectra. Intramolecular one-electron transfer in peroxo vanadates(V) can trigger the generation of radicals, and its dependency upon the nature of the heteroligand is discussed.