Valvular heart disease
Comparison of Multidetector-Row Computed Tomography to Echocardiography and Fluoroscopy for Evaluation of Patients With Mechanical Prosthetic Valve Obstruction

https://doi.org/10.1016/j.amjcard.2009.05.061Get rights and content

For evaluation of prosthetic heart valve obstruction echocardiography and fluoroscopy provide primarily functional information but may not unequivocally establish the cause of dysfunction. Our objective was to evaluate whether multidetector-row computed tomographic (MDCT) imaging could detect the morphologic substrate for such functional abnormalities. Thirteen patients with 15 prosthetic valves, in whom prosthetic valve obstruction was suspected from echocardiography or fluoroscopy but no sufficient cause could be found, underwent electrocardiographically gated multidetector-row computed tomography. MDCT data were retrospectively reconstructed at every 10% of the electrocardiographic interval and analyzed using multiplanar reformatting in anatomically adapted planes. MDCT images were evaluated for morphologic prosthetic and periprosthetic abnormalities. Results could be compared to intraoperative findings or autopsy in 7 patients. Multidetector-row computed tomography disclosed a morphologic substrate for obstruction in 8 of 13 patients. MDCT findings compatible with obstruction were confirmed at surgery or autopsy in 6 patients. In a seventh patient, incomplete leaflet closure found with multidetector-row computed tomography was confirmed at surgery. The most commonly identified causes for obstruction were subprosthetic tissue (6 patients) and abnormal anatomic orientation (3 patients). Despite an indication for surgery, 2 patients were not operated on due to recurrent bacteremias and prohibitive co-morbidity. Multidetector-row computed tomography detected leaflet motion restriction in 7 patients compared to 4 by fluoroscopy. Confirmation of leaflet restriction was available in 5 patients. Multidetector-row computed tomography missed a periprosthetic leak. In conclusion, this initial experience demonstrates that multidetector-row computed tomography can identify causes of prosthetic valve obstruction that constitute indications for surgery but are missed at echocardiography or fluoroscopy.

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Methods

In this retrospective study we included 13 consecutive patients with 15 mechanical prosthetic valves who had undergone cardiac multidetector-row computed tomographic (MDCT) scanning from January 2005 to August 2008 and in whom PVO of unknown cause was present. During the study period, 6 patients presented with evident thrombotic obstruction or hemodynamic instability and were not included. Reasons for MDCT scanning were suspected coronary disease, evaluation of suspected aortic root pathology,

Results

Thirteen patients (6 men, age 35 to 84 years) underwent MDCT scanning. Fifteen mechanical prosthetic valves were present. The group included 10 patients with isolated aortic valves, 2 patients with aortic and mitral valves, and 1 patient with a mitral prosthesis. One of the 2 patients with aortic and mitral prostheses had obstruction of the 2 valves (patient 12). In total 14 of 15 valves were obstructed. Patient characteristics are presented in Table 1.

Presence of important periprosthetic leaks

Discussion

Our study, which describes our initial experience with multidetector-row computed tomography, shows that purely morphologic differentiation provided valuable additional findings in 8 of 13 patients with PVO. These additional findings constituted indications for surgery in 8 patients. Importantly, multidetector-row computed tomography could directly visualize subprosthetic tissue proliferation in 6 patients, which is notoriously difficult to detect by other techniques.13, 14 These findings were

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