Usefulness of mean platelet volume as a biomarker for long-term outcomes after percutaneous coronary intervention.

Larger size platelets have enhanced reactivity. The mean platelet volume (MPV) is a marker of platelet activation and is usually measured as part of blood testing. The aim of the present study was to investigate the utility of the MPV as a biomarker in prognosticating the long-term outcomes after percutaneous coronary intervention (PCI). The baseline MPV values from consecutive patients undergoing PCI were screened. Of the 1,432 patients, the composite primary end point of mortality or myocardial infarction at 1 year occurred in 80 (5.6%). The patients in the highest tertile (MPV >9.1 fL) had an increased frequency of the primary end point compared to those in the mid (8.1 to 9.1 fL) and lowest (<8.1 fL) tertiles (9.0%, 4.5%, and 3.5%, respectively; p <0.01). Logistic regression analysis demonstrated diabetes (odds ratio 2.44, 95% confidence interval 1.48 to 4.00) and highest tertile of MPV (odds ratio 2.42, 95% confidence interval 1.47 to 3.99) as the best predictors of adverse outcomes. In patients with acute coronary syndrome, the preprocedural MPV and troponin levels demonstrated a comparable predictive relation to the primary end point (receiver operator characteristics curve analysis, area under the curve 0.64, p = 0.01; and 0.63, p = 0.01, respectively). In conclusion, an elevated MPV was a strong independent predictor of long-term outcomes after PCI. The preprocedural MPV had prognostic value similar to that of troponin in patients with acute coronary syndrome. These findings could be of importance in the clinical evaluation of patients before PCI and the design of future studies assessing antiplatelet therapies.

Temporal artery biopsy for giant cell arteritis.

OBJECTIVE: To evaluate the influence of temporal artery biopsy (TAB) techniques on establishing a diagnosis of giant cell arteritis (GCA). METHODS: A retrospective review of 141 TAB pathology records from 1996 to 2002 was conducted. Histopathology slides on 136 TAB were reviewed by a single, independent, blinded pathologist. RESULTS: The population included 101 (71.6%) women, mean age 75.8 years (range 45-92), and 40 men, mean age 73.9 years (range 47-90). The mean length of a TAB sample after formalin fixation was 1.76 cm (range 0.1-5.3). Surgeons performing the TAB represented 6 disciplines. Ophthalmologists had the largest volume, at 78 biopsies (55.3%), and the longest segments of artery, with a mean length of 2.37 cm (range 0.4-5.3) (p < 0.001). Comparison of biopsy interpretation provided a kappa coefficient of 0.8 (95% CI 0.69, 0.91). The 38 (27%) positive biopsies had a mean length of 2.07 cm (SD 1.1), and the 98 negative biopsies a mean length of 1.69 cm (SD 1.04) (p = 0.058). Biopsies < 1.0 cm length (n = 35, 25.7%) were less likely to be positive than those > or = 1.0 cm (p = 0.037). No significant differences in surgical discipline, hospital site, number of slides, or cross-sections/cm artery were found between the positive and negative biopsies. CONCLUSION: Biopsy specimens reported positive for GCA tended to be longer than those reported as negative. A "threshold" size of 1.0 cm is associated with increased diagnostic yield. Lack of standardization of biopsy harvesting and processing techniques may contribute to variable sensitivity of TAB.