Endothelial activation after coronary artery bypass surgery : comparison between on-pump and off-pump techniques

Background - The effects of off-pump coronary artery bypass (OPCAB) surgery on endothelial cell activation are poorly understood. Endothelial cell adhesion molecules (CAMs) are expressed and released when the endothelium is activated. We compared plasma CAMs (E-selectin, ICAM-1 and VCAM-1) and HUVEC expression of the same CAMs when exposed to plasma taken before, during and after OPCAB or on-pump coronary surgery (CABG). Methods - Patients undergoing first time CABG (n = 10) or OPCAB (n = 10) had 6 blood samples taken before surgery and up to 24 h post-operatively. Plasma samples were assayed for E-selectin, ICAM-1 and VCAM-1. The same plasma samples were exposed to HUVEC cultures and cell-surface expression of E-selectin, ICAM-1 and VCAM-1 measured. Data are expressed as mean ± SEM of n subjects. Results - Plasma E-selectin was unchanged. Plasma ICAM-1 and VCAM-1 were elevated 24 h post-operatively in both groups (P < 0.01), with no differences between the groups. Twenty-four hours post-OPCAB plasma increased basal and IL-1β induced expression of endothelial VCAM-1 by 133 ± 16% and 140 ± 27% (P < 0.05), respectively. Plasma taken 3 h post-CABG decreased endothelial VCAM-1 expression by 76 ± 10% (P < 0.05). Peri-operative plasma had no effect on endothelial expression of E-selectin or ICAM-1 in either group. Conclusions - OPCAB and CABG with CPB appear to generate qualitatively different inflammatory responses with respect to endothelial activation, which may have clinical implications.8 page(s

Incidence and determinants of myocardial infarction following percutaneous coronary interventions according to the revised Joint Task Force definition of troponin T elevation

Background: Elevations in troponin T (TnT) occur frequently following percutaneous coronary intervention (PCI) and are associated with an adverse prognosis. The Joint ESC/ACC/AHA/WHF Task Force have released a proposal for a universal definition of myocardial infarction (MI), including diagnostic criteria for PCI associated MI. This is based on a TnT cut-point of more than three times the 99th percentile (0.03 ng/ml), which better reflects the precision of the assay. Our study investigated the incidence and predictive factors of a PCI associated MI, using the revised definition. Methods: 325 patients were studied following PCI with stenting. TnT was collected at both 8 and 18 h following PCI in patients with either stable or unstable angina and normal baseline TnT levels. Comparison was made of both clinical and procedural characteristics of patients with and without a rise in TnT following intervention, using cut points of 0.01 and 0.03 ng/ml. Results: TnT was elevated ≥ 0.03 ng/ml in 27% and ≥ 0.01 ng/ml in 39% of patients following PCI. Troponin elevation was significantly more likely in those patients who experienced peri-procedural ischemic symptoms or EKG changes, or in whom abciximab was used. The variables associated with a troponin rise showed a greater difference between TnT positive and negative patients when using 0.03 ng/ml compared to 0.01 ng/ml, suggesting that this may be a better definition of PCI-related MI. Conclusions: Approximately one-quarter of low risk patients experience a procedural MI according to the revised definition. Rises in troponin were significantly associated with peri-procedural ischemic symptoms and EKG changes, and abciximab use, consistent with this level of TnT reflecting true myocardial necrosis.7 page(s