Assessment of left ventricular function with computed tomography and magnetic resonance in patients with low ejection fraction scheduled for coronary artery bypass grafting: a preliminary study.

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 METHODS: In 18 patients (2 women, 16 men) with the EF of 40% or lower scheduled for CABG, cardiac 1.5T MRI and 16­slice CT were performed within 48 hours before surgery. All MRI scans were analyzable; 5 CT exams were excluded due to poor quality. Between­method agreement was assessed using the analysis of correlation and the Bland­Altman plots. RESULTS: The end­systolic volume (ESV), end­diastolic 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 Bland­Altman 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.

A single dose of aprotinin prevents platelet hyporeactivity after coronary artery bypass graft surgery.

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 metabolites of thromboxane A2 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 A2 metabolite excretion after CABG. CONCLUSIONS: Our results indicate that aprotinin may reduce perioperative bleeding by its interference 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.

Integrated minimally invasive direct coronary artery bypass grafting and angioplasty for coronary artery revascularization.

OBJECTIVE: Minimally invasive direct coronary artery bypass (MIDCAB) through the anterolateral minithoracotomy has become a promising therapeutic option in patients with lesion in left anterior descending artery (LAD), especially in multimorbid, elderly and reoperated patients with type C or B lesions. To expand the benefits of MIDCAB concept to patients with multivessel disease, a hybrid myocardial revascularization procedure (HMR) combining surgery of the LAD with interventional procedures for additional coronary lesions has recently been introduced. METHODS: Between January 1999 and September 2001, 50 patients (37 male, 13 female, mean age 54.8+/-20.1 years) underwent an HMR procedure. MIDCAB with endoscopic left internal thoracic artery (LITA) harvesting, followed by percutaneous coronary intervention (PCI) for additional coronary lesions and percutaneous transluminal coronary angioplasty (PTCA), was performed in 11 patients (22%) and stenting in 39 patients (78%). Angiographic assessment of graft patency was performed in all patients during the PCI procedure. The clinical follow-up period was 3-32 months. RESULTS: There were no early and late deaths. Baseline Canadian Cardiology Society (CCS) class was 2.8+/-0.7 versus 1.1+/-0.9 (P<0.001) 30 days after HMR procedure. There were no major acute in-hospital cardiac events. Angiographic studies showed patent LIMA-LAD graft in 50 patients (100%). We showed good quality of anastomosis in 49 patients (98%). There was a moderate graft stenosis in one patient (2%). At long term follow-up, the rate of major cardiac events was 12%. Five patients (10%) developed restenosis after PCI, and one patient (2%) developed significant stenosis in site of LITA-LAD anastomosis; redo PCI was performed successfully. CONCLUSIONS: The hybrid procedure is a safe and effective method for complete revascularization in selected patients with double-vessel coronary artery disease (patients with type B or C lesions in the proximal LAD). This method allows performance of complete revascularization with minimization of surgical trauma. So far, long-term results of HMR are limited by the results of PCI.