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Online ISSN 1827-1847
Salvini M., Palmieri P., Bonalumi G., Odero A.
From the Department of Surgery Vascular Surgery Clinic San Matteo Polyclinic, Pavia (Head: Prof. A. Odero) Pavia University
Objective. The rate at which thoracic and thoracoabdominal aneurysms expand is unknown. Transesophageal echocardiography (TOE) could play a fundamental role in establishing the natural history of thoracic aorta ectasias in patients not given surgical treatment. The present paper investigates the accuracy of the technique in providing a reliable estimate of variations in aortic diameter given the impact of inter- and intraobserver variability.
Methods. The study was conducted on 10 patients given TOE for suspected aneurysms of the thoracic or thoracoabdominal aorta. It involved the recording of standard TOE scans (5 MHz biplanar probe, free setting) or SVHS tape and repeated random readings of maximum diameter recorded on the ascending aorta, aortic arch and descending aorta by two independent operators on a blind trial basis.
Statistical analysis. The data thus recorded was subjected to: AOV statistical analysis for repeated readings (differences between measurements and between scans); calculation of the variation coefficient over three readings on each segment studied (intraobserver variability); assessment of intra- and interobserver concordance (correlation coefficient); calculation of the mean absolute differences between readings and between operators together with confidence limits (variability expressed in terms of diameter variations revealed by independent readings).
Results. Analysis of the results showed that diameter estimates were readily repeatable (intraoperator variation coefficient 0-17%) in all aortic segments but less accuracy in assessments of the aortic arch. The intra/interoperator correlation coefficient was close to 1 on all segments (a linear relationship that was statistically significant) and the confidence limit on the mean of absolute differences was also under 1 mm, despite occasional absolute differences in of up to 4 mm on the aortic arch when readings exceeded the known limits of aneurysms growth.
Conclusions. The paper concludes that TOE is extremely accurate in terms of inter/intraoperator variability when the mean figures on the entire study population are taken into account. However when the technique is used to judge the degree of expansion in a single aneurysms there may be absolute divergences that render the technique an unreliable basis for clinical decisions, so that any judgement of aneurysm evolution in individual patients should be formulated with extreme caution.
language: English, Italian