Effective valve opening area in the detection of dysfunctional aortic valve prostheses: A differentiated statistical analysis of this parameter including the introduction of minimal expected normal values as borderline to dysfunctional stenotic prostheses

摘要

Background: Dysfunction of heart valve prostheses (VP) is a life-threatening complication and the diagnosis remains difficult. The motivation for this study was to improve the detection of dysfunctional VP by optimizing application of the prosthetic effective orifice area (VA). For this reason the minimal expected normal VA (VA expected) was introduced. Methods: We investigated echocardiographically 1,369 normally functioning aortic valve prostheses (AVP). Mean VA, transprosthetic peak (PPG) and mean pressure gradients (MPG) were evaluated to gain reference values depending on prosthetic size and construction principle. Mean VA expected was calculated by applying a simple formula that was developed empirically using statistical analyses. The results were compared with those of 65 dysfunctional AVPs. Results: VA expected can be applied as a threshold between normal and dysfunctional stenotic AVP and showed a correct estimation in 87% of all normally functioning and 100% of dysfunctional stenotic VPs. The sensitivity for all prosthetic sizes is 1.0, independently of the constructional principle of the VP. Specificity ranged between 0.8 and 1.0, dependent on VP size. The formula representing VA expected is simple and can be executed easily. Conclusion: As nearly independent of stroke volume and in consideration of VA expected, VA seems to have become one of the preferable parameters for detecting pathological stenotic AVPs echocardiographically. The additional application of PPG/MPG and other parameters permits prostheses with relevant isolated regurgitation and patient-prosthesis-mismatch to be distinguished. (Echocardiography 2012;29:713-719)