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ACCURACY OF ECHOCARDIOGRAPHY IN THE MEASUREMENT OF PULMONARY PRESSURE IN LIVER TRANSPLANTATION EVALUATION
L Roth1, B Dias2, M Levstik1
1Division of Gastroenterology; 2Division of Cardiology, London Health Sciences Centre, London, Ontario
Aims: Cardiac testing is standard in patients undergoing evaluation for orthotopic liver transplant. Echocardiography is used to discover pulmonary hypertension, which is a contraindication to liver transplantation, however, the accuracy of measuring pulmonary pressures in this population has yet to be tested. Given that decisions regarding candidacy for a donor organ relies on this measurement, appropriate recipients may be excluded inadvertently. This study aims to compare pulmonary pressures using echocardiography with direct pulmonary artery catheterization measurement.
Methods: Data was collected from the 100 most recent liver transplant recipients at the London Health Sciences Centre. Preoperative echocardiograms were reviewed, as were values for the pulmonary artery pressure from a pulmonary artery catheter inserted immediately preoperatively. This data was then compared using a paired T-score test.
Results: Data was reviewed from 100 patients. Five patients were undergoing repeat transplantation and therefore did not have a preoperative echocardiogram, as did 5 other patients for various reasons. From the 90 patients who had complete data available, the echocardiographer did not or was unable to measure the pulmonary artery pressures in 21 patients which reduced the number of patients included in the analysis to 69. In addition, in 39 cases the echocardiographer did not quantify this value, but rather reported it as "normal". These values were included in the analysis at a value of 35 mmHg.
The average difference was 4.623 ± 9.759 mmHg in favour of echocardiography overestimating the pulmonary pressures when compared to pulmonary artery catheterization at the time of surgery. This difference was significant when calculated using a paired T-score test, t(68)=-3.935; p<0.001.
Conclusions: Echocardiographic measurement of pulmonary artery pressure in patients undergoing liver transplantation may be higher than direct pulmonary artery pressure measurement preoperatively, potentially excluding appropriate candidates from liver transplantation. Further research in this area is warranted in order to improve our pretransplant assessment.