| Background: Approximately 250.000 patients worldwide undergo heart valve replacement each year using either a biological (porcine or pericardial) or mechanical (carbon/metal) prosthetic heart valve (PHV). Biological PHV structurally decline in 10-15 years and mechanical PHV carry an approximate 0.1-0.4% per patient-year risk of valve failure and dysfunction. Therefore patients remain under life long follow-up using non-invasive echocardiography which provides both functional and anatomical information and is especially suited to confirm normal valve function. But when echocardiography detects an elevated pressure gradient over the valve as a sign of valve dysfunction, this often presents diagnostic and therapeutic dilemmas. A high-risk and costly re-operation to replace the PHV may be needed but echocardiography fails to diagnose the cause of dysfunction in up to 51% of patients (Girard, JACC 2001). Multidetector-row CT (MDCT) is a non-invasive cardiac imaging method that provides 4D datasets and is used for coronary assessment but only recently has shown potential to visualize prosthetic cardiac valves as well. Hypothesis: - MDCT imaging will image all 6 PHV types included in this study with diagnostic image quality to evaluate the supra-, sub- and valvular anatomy as well as leaflet motion and opening and closing angles in cine mode. - MDCT will provide additional diagnostic information to echocardiography and fluoroscopy that will result in a change in patient management in >19% of patients with suspected PHV dysfunction. Objectives: To determine: 1.The range of normal MDCT imaging characteristics for 6 commonly implanted PHV. 2. How often MDCT provides additional diagnostic information that changes patient management in patients with suspected PHV dysfunction Methods: Observational study. MDCT imaging of the PHV will be performed at the first routine follow-up visit in 120 patients that underwent PHV implantation and have normal routine follow-up transthoracic echo. MDCT images are evaluated for optimal imaging phase, artefacts and the ability to assess supra-, sub- and valvular anatomy as well as leaflet motion and measure opening and closing angles. Findings are related to intra- and postoperative echocardiography findings to obtain a normal reference standard. An additional 100 patients with suspected PHV dysfunction will undergo an extensive workup including 1. transthoracic and transesophageal echo-Doppler, and 2. fluoroscopy (except for biological valves). The most likely cause of PHV dysfunction and intended patient management based on these test is recorded. Subsequently, patients undergo MDCT and the cause for PHV according to MDCT is recorded as well as changes in patient management when disclosed. Findings at re-operation or pathology serve as the gold standard to which the diagnostic accuracy for the cause of PHV dysfunction by echocardiography and MDCT is compared. Expected results: This study will provide a reference standard for normal in-vivo MDCT imaging findings of 6 PHV types. The study will also determine the additional diagnostic value of MDCT to echocardiography and fluoroscopy in patients with suspected PHV dysfunction. Given our in-vitro data and preliminary clinical data, we expect MDCT to provide sufficient image quality and additional diagnostic information to echo that will result in a change in patient management in >19% of patients with suspected PHV dysfunction. Objectives To determine: 1. the normal range of MDCT imaging findings of the supra-, sub- and valvular anatomy as well as leaflet motion and opening and closing angles in cine mode in patients with 6 commonly impanted types of prosthethic heart valves. 2. how often MDCT provides additional diagnostic information to echocardiography and fluoroscopy and how often this MDCT information results in a correct change in management in patients with suspected PHV dysfunction. Relevance for cardiovascular diseases With the recent developments in cardiac multidetector-row CT (MDCT) a novel non-invasive technique for prosthetic heart valve (PHV) assessment has emerged. MDCT is especially likely to improve the diagnostics and management of patients with PHV dysfunction by providing the opportunity to dynamically visualize the prosthesis in any desired imaging plane. This will provide unique diagnostic information on the cause of PHV dysfunction that complements the functional information obtained by echocardiography. This study will provide important normal MDCT reference values for 6 different PHV types which is an essential part of introducing this new diagnostic modality. Furthermore, this study will determine the actual effect of MDCT imaging on pre-operative diagnosis of the cause of PHV dysfunction and its impact on patient management. Keywords imaging - surgery - tomography - valves |
