Fatal case of accidental perforation of ileum by pace wires during coronary bypass grafting.

In many centres, epicardal pace wires are routinely implanted during coronary artery bypass surgery to treat postoperative tachy- and brady-arrhythmias. We describe the case of an 88-year-old male, with severe comorbidity, who underwent a successful CABG, but incurred an unacknowledged iatrogenic perforation of the ileum with the placement of an epicardial pace wire. The patient developed septic shock and multi organ failure despite intra-abdominal surgical interventions and intensive care therapy, and died 6 days after CABG.

Optimal preservation of porcine cardiac tissue prior to diffusion tensor magnetic resonance imaging.

The effects of ex vivo preservation techniques on the quality of diffusion tensor magnetic resonance imaging in hearts are poorly understood, and the optimal handling procedure prior to investigation remains to be determined. Therefore, 24 porcine hearts were examined in six groups treated with different preservation techniques, including chemical fixation and freezing. Diffusion properties of each heart were assessed with diffusion tensor imaging in terms of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da) and radial diffusivity (Dr). Tractography was performed to visualize the course of the cardiomyocytes, assuming greater diffusivity in the longitudinal than the transverse axis of individual cardiomyocytes. Significant differences in MD, Da and Dr were found, as well as in FA between groups (P < 0.001). Freezing of specimens resulted in the lowest mean FA of 0.21 (0.06) and highest Dr of 8.92 (1.5) mm2 s(-1) . The highest mean FA was found to be 0.43 (0.11) in hearts perfusion-fixed with formalin. Calculated tractographies were indistinguishable among groups except in frozen specimens, where no fibres could be tracked. Perfusion fixation with formalin provided the best tractography, but immersion fixation yielded diffusion data most similar to fresh hearts. These findings suggest that parameters derived from diffusion tensor imaging in ex vivo hearts are sensitive to fixation and storage methods. In particular, freezing of specimens should be avoided prior to diffusion tensor imaging investigation due to significant changes in diffusion parameters and subsequent image deteriorations.

Dynamic geometry of the left ventricular outflow tract of pigs with induced supravalvular aortic stenosis.

OBJECTIVES: Detailed information about the dynamic geometry of the left ventricular outflow tract (LVOT) is of great importance for transcatheter aortic valve implantation (TAVI), since these valves utilize the LVOT as a landing zone for optimum placement and fixation. The LVOT is generally considered circular in shape and stable in its conformation. However, recent studies indicate that this may not be the case. METHODS: Twenty-two 5-kg pigs (± 0.47 kg) were randomly allocated to either aortic banding (n = 14) or sham operation (n = 8). LVOT dynamic geometry was assessed using cardiovascular-magnetic resonance imaging, 9 weeks after banding of the ascending aorta. RESULTS: All the banded animals developed significant left ventricular hypertrophy (P = 0.01) compared with controls. All the animals demonstrated significant reduction in eccentricity index (P(intervention) < 0.01, P(control) < 0.05) and longest internal diameter (P(intervention) < 0.01, P(control) = 0.02) when comparing measurements from end-diastole to end-systole. No significant systolic or diastolic differences were found between the two groups. CONCLUSIONS: The main findings were: the LVOT (i) undergoes substantial geometric alterations throughout the cardiac cycle and (ii) is ellipsoid throughout the cardiac cycle, (iii) geometric changes during the cardiac cycle stems from compression of the long-axis of the LVOT and (iv) dynamic geometry did not change significantly after induction of significant LV hypertrophy. Thus, our data suggest that assumptions made in daily practice, of a circular and stable LVOT geometry, need to be revised.