This study shows the risk of intracranial hemorrhage is not decreased by choosing lower intensity anticoagulation, and target INR should still be kept at 2.5 among elderly patients. However, patients older than 85 years should be counseled about their higher risk of intracranial hemorrhage.
3. Heeschen C, Hamm CW, Mitrovic V, et al. N-terminal pro-B-type natriuretic peptide levels for dynamic risk stratification of patients with acute coronary syndromes. Circulation. 2004;110: 3206-12.
Recent data demonstrate the prognostic value of assessment of neurohormonal activation in patients with acute coronary syndromes (ACS). B-type natriuretic peptide levels (BNP) and levels of the N-terminal fragment of the BNP prohormone (NT-proBNP) predict adverse long-term outcomes in patients with ACS. Investigators reviewed plasma samples of Troponin T (TnT) and NT-proBNP obtained from patients with ACS enrolled in the Platelet Receptor Inhibition in Ischemic Syndrome Management (PRISM) trial, which randomized patients to tirofiban or heparin for 48 hours and assessed mortality and myocardial infarction at 30 day follow-up. TnT and NT-proBNP determinations were available at baseline for 1791 patients, and at 48 and 72 hours from 1401 patients. Baseline NT-proBNP levels >250 ng/L were associated with significantly higher rates of death and myocardial infarction at 7 and 30 day follow-up. After adjustment for TnT and C-reactive protein levels, elevated NTproBNP levels maintained its predictive value (OR 2.7; p<.001). In patients with normal TnT levels, NT-proBNP levels identified a subgroup of patients at increased risk (OR 3.0; p=.004). However, in patients with high TnT levels (>0.1 mcg/L), NT-proBNP lost its predictive value (p=.58). More importantly, patients with normal levels of both TnT and NT-proBNP were at very low risk (0.6% event rate at 30 day follow-up).
Serial determinations of NT-proBNP levels at 48 and 72 hours were reviewed in patients without major adverse cardiac events (death or myocardial infarction); these patients were subdivided into groups with and without refractory ischemia. Patients without refractory ischemia showed a significant decline in NT-proBNP levels, whereas patients with refractory ischemia had no significant change. Persistently elevated NT-proBNP levels at 72 hours were associated with a 17.2% risk of death or MI at 30 days, compared with 0.6% risk if NT-proBNP returned to normal at 72 hours (p<.001). Neither TnT nor C-reactive protein demonstrated similar predictive value.
The study is limited by its retrospective nature, by potential selection bias by including only patients with direct evidence of coronary artery disease, and by limitations of the generalizability of its findings (e.g., to emergency department patients with chest pain).
As BNP and NT-proBNP are counter-regulatory hormones that play an active role in the response to ischemic injury, the authors suggest that NT-proBNP is a promising tool for dynamic risk assessment in patients with ACS. The authors also do not differentiate between BNP and NT-proBNP with regard to use in risk stratification, which might lead one to believe that these tests share similar predictive value. (Of note, the study was entirely funded by a company that produces an assay for NT-proBNP). Prospective trials to validate this tool are warranted
4. Heuschmann PU, Kolominsky-Rabas PL, Roether J, et al. Predictors of in-hospital mortality in patients with acute ischemic stroke treated with thrombolytic therapy. JAMA. 2004;292:1831-38.
The objective of this study was to identify factors associated with in-hospital mortality in ischemic stroke patients treated with recombinant tissue plasminogen activator (tPA). It was a prospective observational cohort study of 1658 patients conducted at 225 community and academic hospitals throughout Germany with main outcome of in-hospital mortality.
In this study 10% of patients who were treated with tPA died during their hospital stay, with 2/3 of deaths occurring in the first 7 days. Relative probability of in-hospital mortality increased with increasing patient age, with an odds ratio (OR) of 1.6 for each 10-year increment in age. Age was an independent predictor of in hospital mortality irrespective of tPA administration, with patients older than 75 years age having 4 fold higher mortality than the youngest cohort of less than 55 years age.