Prosthesis-Patient Mismatch in Bovine Pericardial Aortic Valves

Abstract

Background-The prevalence of prosthesis-patient mismatch (PPM) and its impact on survival after aortic valve replacement have not been clearly defined. Historically, the presence of PPM was identified from postoperative echocardiograms or preoperative manufacturer-provided charts, resulting in wide discrepancies. The 2009 American Society of Echocardiography (ASE) guidelines proposed an algorithmic approach to calculate PPM. This study compared PPM prevalence and its impact on survival using 3 modalities: (1) the ASE guidelines-suggested algorithm (ASE PPM); (2) the manufacturer-provided charts (M PPM); and (3) the echocardiographically measured, body surface area-indexed, effective orifice area (EOAi PPM) measurement. Methods and Results-A total of 614 patients underwent aortic valve replacement with bovine pericardial valves from 2004 to 2009 and had normal preoperative systolic function. EOAi PPM was severe if EOAi was ≤0.60 cm 2 /m 2 , moderate if EOAi was 0.60 to 0.85 cm 2 /m 2 , and absent (none) if EOAi was ≥0.85 cm 2 /m 2 . ASE PPM was severe in 22 (3.6%), moderate in 6 (1%), and absent (none) in 586 (95.4%). ASE PPM was similar to manufacturer-provided PPM (P=1.00). ASE PPM differed significantly from EOAi PPM (P<0.001), which identified severe mismatch in 170 (29.7%), moderate in 191 (33.4%), and absent (none) in 211 patients (36.9%). Irrespective of the PPM classification method, PPM did not adversely affect midterm survival (average follow-up, 4.1±1.8 years; median, 3.9 years; range, 0.01-8 years). There were no reoperations for PPM. Conclusions-In patients with normal systolic function undergoing bovine pericardial aortic valve replacement, the prevalence of PPM using the algorithmic-ASE approach was low and correlated well with manufacturer-provided PPM. Independent of the method of PPM assessment, PPM was not associated with medium-term mortality. The 2009 American Society of Echocardiography (ASE) guidelines suggested an alternative algorithmic approach for evaluating prosthetic aortic valves and identifying PPM. 16 In this model, PPM was only considered if certain other criteria besides EOA were met. It was suggested that if true PPM existed, it would be corroborated by abnormal echocardiographic measurements of aortic jet velocity, acceleration time, and dimensionless velocity index.The relative prevalence of PPM using these 3 methods has not been studied in patients with normal left ventricular (LV) function undergoing AVR. In this investigation, we determined the prevalence of PPM after AVR using the 3 methods (EOAi, manufacturer based, and ASE guidelines based) and assessed PPM association, as identified by any of the above approaches, with medium-term survival. MethodsData for this project were obtained from the Cardiovascular Research Database (CARD) in the Clinical Trials Unit of the Bluhm Cardiovascular Institute at Northwestern Memorial Hospital. This database was approved by the Institutional Review Board at Northwestern University (project # STU00012288). Any subjects refusing partici...

Response to Letter Regarding Article, “Prosthesis-Patient Mismatch in Bovine Pericardial Aortic Valves: Evaluation Using 3 Different Modalities and Associated Medium-Term Outcomes”

“…2 To keep the study cohort homogenous, we preselected only patients with normal systolic function who underwent an aortic valve replacement with a pericardial tissue valve. We agree that there is a small likelihood of underestimation of the prevalence of prosthesis-patient mismatch (PPM) in our cohort because of low gradient aortic stenosis and normal systolic function, a group of patients who are challenging to evaluate and manage.…”

Letter by House et al Regarding Article, “Prosthesis-Patient Mismatch in Bovine Pericardial Aortic Valves: Evaluation Using 3 Different Modalities and Associated Medium-Term Outcomes”

“…In a recent edition of Circulation: Cardiovascular Imaging, Chacko et al 2 propose applying the American Society of Echocardiography guidelines for prosthetic valves to exclude the presence of PPM. In these guidelines, there is a useful algorithm for the evaluation of high transprosthetic gradients.…”