Temporal Evolution of Serum Concentrations of High-Sensitivity Cardiac Troponin During 1 Year After Acute Coronary Syndrome Admission

BACKGROUND: Detailed insights in temporal evolution of high-sensitivity cardiac troponin following acute coronary syndrome (ACS) are currently missing. We aimed to describe and compare the post-ACS kinetics of high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT), and to determine their intra- and interindividual variation in clinically stable patients. METHODS AND RESULTS: We determined hs-cTnI (Abbott) and hs-cTnT (Roche) in 1507 repeated blood samples, derived from 191 patients with ACS (median, 8/patient) who remained free from adverse cardiac events during 1-year follow-up. Post-ACS kinetics were studied by linear mixed-effect models. Using the samples collected in the 6- to 12-month post-ACS time frame, patients were then considered to have chronic coronary syndrome. We determined (differences between) the average hs-cTnI and average hs-cTnT concentration, and the intra- and interindividual variation for both biomarkers. Compared with hs-cTnT, hs-cTnI peaked higher (median 3506 ng/L versus 494 ng/L; P<0.001) and was quicker below the biomarker-specific upper reference limit (16 versus 19 days; P<0.001). In the post–6-month samples, hs-cTnI and hs-cTnT showed modest correlation (rspearman=0.60), whereas the average hs-cTnT concentration was 5 times more likely to be above the upper reference limit than hs-cTnI. The intraindividual variations of hs-cTnI and hs-cTnT were 14.0% and 18.1%, while the interindividual variations were 94.1% and 75.9%. CONCLUSIONS: Hs-cTnI peaked higher after ACS and was quicker below the upper reference limit. In the post–6-month samples, hs-cTnI and hs-cTnT were clearly not interchangeable, and average hs-cTnT concentrations were much more often above the upper reference limit than hs-cTnI. For both markers, the within-patient variation fell largely below beween-patient variation. REGISTRATION: URL: https://www.trialregister.nl; unique identifiers: NTR1698 and NTR1106

A dose-finding study of fondaparinux in patients with non-ST-segment elevation acute coronary syndromes

AbstractObjectivesIn this dose-finding study, we sought to compare fondaparinux with enoxaparin in patients with acute coronary syndromes (ACS).BackgroundFondaparinux is a synthetic pentasaccharide that selectively inhibits activated clotting factor X. It has been demonstrated as effective in preventing thromboembolic complications in orthopedic surgery.MethodsFour doses fondaparinux (2.5, 4, 8, or 12 mg once daily) and enoxaparin (1 mg/kg twice daily) were compared, both given for three to seven days, in patients with ACS without persistent ST-segment elevation.ResultsThe rates of the combined primary end point of death, myocardial infarction, or recurrent ischemia after nine days were 27.9%, 35.9%, 34.7%, 30.3%, and 35.7% in patients allocated to fondaparinux doses of 2.5, 4, 8, and 12 mg and enoxaparin, respectively (p = NS). In the per-protocol analysis (929 patients who received adequate study drug and had adequate ST-segment monitoring), these figures were 30.0%, 43.5%, 41.0%, 34.8%, and 40.2%. Again, no dose response was observed. The lowest event rates were observed in the 2.5-mg fondaparinux group, which had significantly lower rates than the enoxaparin group as well as for 4 and 8 mg fondaparinux in the per-protocol analysis (p < 0.05). Bleeding rates were low and not different among the patient groups. No differences were observed in fondaparinux concentrations in patients with or without death, myocardial infarction, recurrent ischemia, or bleeding events.ConclusionsThis dose-finding study revealed no dose response for different fondaparinux doses ranging from 2.5 to 12 mg subcutaneously and suggests that the efficacy and safety of fondaparinux may be similar to that of enoxaparin. Further studies with fondaparinux in ACS might include the lowest dose (2.5 mg) investigated in this study