Prediction of Acute Kidney Injury Within 30 Days of Cardiac Surgery

Abstract

Introduction: It is unclear whethermanufacturer provided charts actually predict the probability of aortic valve patientprosthesis mismatch (PPM). The aim of the study was to determine whether these charts reliably predict PPM in patients undergoing aortic valve replacement (AVR). Methods: We undertook a retrospective analysis of echocardiographic data from Geelong Hospital with institutional ethics approval. Between January 2006 and December 2010, 405 patients in our hospital underwent AVR with either a mechanical prosthesis or a stented bioprosthesis. 152 patients had adequate echocardiographic follow up (mean time to follow up 104 days). The measured gradient and effective orifice area index (EOAI) were compared to the values provided by the manufacturer. Results: Despite no patient having preoperatively predicted severe PPM according to manufacturer charts, 62 patients (40.8%) had postoperative echocardiographic evidence of severe PPM. The accuracy of the charts to predict severe PPM was 59.2%. The rate of postoperatively measured moderate or greater PPM was 77.6%. Sensitivity and specificity of manufacturer charts for moderate or greater PPM were 27.1% (19.5–36.2%) and 88.2% (71.6–96.1%) respectively. The accuracy of the charts for moderate or greater PPM was 41.4%. Postoperatively measured average EOA across all valve types and sizes were lower than those provided by the manufacturer. Postoperative aortic valvemean pressure gradient in patients with severe PPM was 18.5 6.3 mmHg, moderate PPM 13.7 4.3 mmHg and no PPM 12.6 3.2 mmHg. Discussion: The accuracy of industry provided charts for EOAI calculation is poor. We conclude that these charts are not useful in the pre-operative prediction of severe PPM in patients undergoing AVR.