Search

Context.—Despite remarkable progress, the diagnosis of acute coronary syndromes (ACS) is still challenging. Objective.—The mean platelet volume (MPV), a simple and reliable indicator of platelet size that correlates with platelet activation, might be an emerging cardiovascular risk marker and potentially helpful in stratifying cardiovascular risk. Design.—We analyzed MPV values in 2304 adult patients who were consecutively admitted during a 1-year period to the emergency department of the University Hospital of Verona for chest pain suggestive of ACS. In all patients, a baseline blood sample was collected for routine hematologic testing, whereas cardiac troponin T measurements were collected both at baseline and after 4, 6, and 12 hours. Results.—A total of 456 patients (19.8% of total) had ACS. These patients, all having cardiac troponin T levels of 0.03 ng/mL or greater in addition to ischemic electrocardiographic changes, had higher MPV values than non-ACS patients with normal cardiac troponin T levels (median, 8.0 fL [5th to 95th percentiles, 6.7–10.0 fL] versus median, 7.4 fL [5th to 95th percentiles, 6.5–9.5 fL]; P < .001). The diagnostic accuracy of MPV, calculated as the area under the curve by the receiver operating characteristic analysis, was 0.661 (P < .001). At the 9.0-fL cutoff, the negative and positive predictive values of MPV were 83% and 43%, respectively. Conclusions.—Because MPV is a simple and inexpensive laboratory measurement, it might be considered a useful rule-out test along with other conventional cardiac biomarkers for the risk stratification of ACS patients admitted to the emergency departments.

Context.—The measurement of cardiac troponin I (TnI) and T (TnT) is essential to diagnose, guide therapy, and predict outcomes of the acute coronary syndrome. Increased levels of troponins, especially TnT, are frequently observed in patients on chronic hemodialysis (HD), reflecting ongoing and subclinical myocardial damage.Objective.—Because these markers are increasingly used for stratification of cardiac risk in these patients, their behavior during HD should be acknowledged to optimize their clinical usefulness.Design.—TnI and TnT were measured in 34 patients pre-HD and post-HD by either high- or low-flux membranes. The post-HD concentrations were corrected for hemoconcentration.Results.—Pre-HD levels above the 99th percentile reference limits of the general population of TnI (>0.06 ng/ mL) and TnT (>0.01 ng/mL) were observed in 9% (13% high-flux, 6% low-flux membranes) and 88% (94% high-flux; 83% low-flux membranes) of the patients, respectively. No significant difference was observed in mean pre-HD values between patients dialyzed by low- and high-flux membranes. The overall decrease post-HD of both troponins (−21% and −17% for TnI and TnT, respectively) only reached statistical significance in patients dialyzed by low-flux membranes (−27% and −37% for TnI and TnT, respectively). A significant correlation was observed between absolute variations of TnI and TnT pre-HD to post-HD.Conclusions.—Results of our investigation attest that high-flux membranes clear both troponins more efficiently from circulation than low-flux membranes. Therefore, sampling time and ultrafiltration coefficient of the HD membrane should be regarded as potential sources of variability in the clinical interpretation of troponin measurement in HD patients.