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  • 1
    Abstract: The aim of this study was to analyse flow characteristics of two different prosthetic valves by means of a non-invasive 3D Doppler technique. As previously demonstrated, negative velocity peaks within a 3D-Doppler profile significantly correlate with the severity of aortic stenosis. Transesophageal echocardiography was performed in 42 patients with normal aortic valves and in 35 patients after aortic valve replacement (bileaflet n=23, tilting-disc n=12). Three-dimensional reconstruction of color Doppler data was performed by the EchoAnalyzer software developed at our institution. Cross-section velocity distribution in the ascending aorta was analysed 2 cm distal to the aortic valve in 3 different sectors (non-coronary (NC), left-coronary (LC) or right-coronary (RC)). The percentages of negative velocity values (PNVV) in native aortic valves (6.8+/-6.4%, range: 0-21.8%) were significantly lower (P〈0.0001) than in prosthetic valves (bileaflet: 38.5+/-18.5%, range: 13.2-71%; tilting-disc: 47.2+/-17.6%, range: 21.7-78.1%). Significant differences between normal and prosthetic valves were found in all different sectors. Furthermore, Medtronic Hall showed significantly higher PNVV than St. Jude Medical within the LC sector (P=0.03). This method, which allows non-invasive analysis of 3D flow distributions in patients, revealed significant differences between prosthetic valves and native valves as well as among different prosthetic types.
    Type of Publication: Journal article published
    PubMed ID: 17670437
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  • 2
    Keywords: Germany ; GENERATION ; SYSTEM ; TOOL ; VOLUME ; DISEASE ; SURGERY ; PATIENT ; PARAMETERS ; Jun ; MANAGEMENT ; monitoring ; cardiac surgery ; ejection fraction ; pulmonary artery catheter ; right ventricle ; thermodilution ; transesophageal 3D echocardiography ; TRANSESOPHAGEAL ECHOCARDIOGRAPHY
    Abstract: Objective: Right ventricular function is an important aspect of global cardiac performance which affects patients' outcome after cardiac surgery. Due to its geometrical complexity, the assessment of right ventricular function is still a very difficult task. Aim of this study was to investigate the value of a new technique for intraoperative assessment of right ventricle based on transesophageal 3D-echocardiography, and to compare it to volumetric thermodilution by using a new generation of fast response thermistor pulmonary artery catheters. Methods: Twenty-five patients with coronary artery disease underwent 68 intraoperative measurements by 3D-echocardiography and thermodilution simultaneously. Following parameters were analysed: right ventricular end-diastolic volume (RVEDV), end-systolic volume (RVESV) and ejection fraction (RVEF). Pulmonary, systemic and central venous pressures were simultaneously recorded. Segmentation of right ventricular volumes were obtained by the 'Coons-Patches' technique, which was implemented into the EchoAnalyzer (R), a multitask system developed at our institution for three-dimensional functional and structural measurements. Results: Right ventricular volumes obtained by 3D-echocardiography did not show significant correlations to those obtained by thermodilution. Volumetric thermodilution systematically overestimates right ventricular volumes. Significant correlations were found between RVEF measured by 3D-echocardiography and those obtained by thermodilution (r=0.93; y=0.2+0.80x; SEE=0.03; P 〈 0.01). Bland-Altmann analysis showed that thermodilution systematically underestimates RVEF. The bias for measuring RVEF was +15.6% with a precision of +/- 4.3%. The patients were divided into two groups according to left ventricular function. The group of patients with impaired function showed significantly tower right ventricular ejection fraction (44.1 +/- 4.6 vs. 55.1 +/- 3.9%; P 〈 0.01). Conclusions: Three-dimensional echocardiography provides a useful non-invasive tool for intraoperative and serial assessment of right ventricular function. This new technique, which overcomes the limitations of previous methods, may offer key insights into management and outcome of patients with severe impairment of cardiac function. (c) 2005 Elsevier B.V. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 15896606
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