PlA1 homozygotes normally had a greater risk of perioperative bleeding. Capillary closure time had no advantage relative to Simplate bleeding time in predicting postoperative blood loss. Aspirin pretreatment revealed no beneficial effects and resulted in increased postoperative bleeding and requirement for blood product transfusions after coronary artery bypass grafting in patients with stable angina. It was most unfavorable for PlA2 carriers.

IntroductIon Reliable estimation of left ventricular (LV) parameters with the use of computed tomography (CT) has not been verified in patients with low ejection fraction (EF) so far.objectIves The aim of this preliminary study was to assess the agreement between magnetic resonance imaging (MRI) and CT in the assessment of the LV volume and EF in patients with low EF scheduled for coronary artery bypass grafting (CABG). PAtIents And methodsIn 18 patients (2 women, 16 men) with the EF of 40% or lower scheduled for CABG, cardiac 1.5T MRI and 16-slice CT were performed within 48 hours before surgery. All MRI scans were analyzable; 5 CT exams were excluded due to poor quality. Between-method agreement was assessed using the analysis of correlation and the Bland-Altman plots.results The end-systolic volume (ESV), end-diastolic volume (EDV), and stroke volume (SV) were higher when measured by MRI compared with CT (P <0.05 for all). The EF values measured by both methods were comparable. We observed a strong positive correlation between MRI and CT in the measurement of ESV (R = 0.86), EDV (R = 0.71), and EF (R = 0.68), but there was no correlation for SV (R = 0.07). The Bland-Altman analysis confirmed that the LV volumes assessed by MRI were higher compared with those determined by CT. There was also a trend for larger differences between the 2 methods in the measurement of ESV and EDV. The EF value was higher on MRI compared with CT but the difference was nonsignifiact.conclusIons In patients with coronary artery disease and low EF, the EF values measured by MRI and CT are comparable, but the ESV, EDV, and SV parameters cannot be used interchangeably due to their underestimation on CT.

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INTROduCTION Bleeding after coronary artery bypass graft (CABG) surgery is associated with a significant increase in mortality. Even though aprotinin significantly reduces bleeding in patients undergoing cardiac surgery, its use has been recently substantially limited because of serious cardiovascular complications. The exact mechanism of its action, particularly its effect on platelet function, remains unclear. ObjECTIvEs The aim of the study was to assess the effect of aprotinin on platelet function in patients undergoing CABG. PATIENTs ANd mEThOds In a randomized placebo-controlled double-blind study, we investigated the effect of a single dose of aprotinin on platelet function in 24 patients who underwent CABG between 2005 and 2006. Before surgery and in the postoperative period, we measured platelet activation markers (P-selectin and activated form of glycoprotein IIb/IIIa) at baseline and following in vitro platelet activation with adenosine diphosphate (ADP) or protease-activated receptor 1 (PAR-1) agonist-thrombin receptor activator for peptide 6 (TRAP-6). Perioperative bleeding and urinary meta bolites of thromboxane A 2 were also determined. REsuLTs Aprotinin reduced perioperative bleeding by 26% (P <0.01) and prevented a decrease in platelet sensitivity to ADP immediately after CABG. In vitro platelet reactivity to TRAP-6 remained unchanged. Aprotinin did not affect blood platelet count or urinary thromboxane A 2 meta bolite excretion after CABG. CONCLusIONs Our results indicate that aprotinin may reduce perioperative bleeding by its inter ference with ADP pathway of platelet activation, thereby preventing postoperative hyporeactivity of platelets to ADP. Platelet reactivity to PAR-1 receptor agonist was not affected by aprotinin.

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