Diagnostic value of multidetector computed tomography in evaluating mechanical prosthetic valve complications at Hanoi Heart Hospital

Objective: To evaluate the diagnostic performance of multidetector computed tomography (MDCT) in detecting complications of mechanical aortic and mitral prosthetic valves. Methods: A diagnostic accuracy study with a retrospective cross-sectional design was conducted in 39 patients with 42 mechanical aortic and/or mitral prosthetic valves who underwent cardiac MDCT at Hanoi Heart Hospital because of suspected prosthetic valve complications. MDCT findings were compared with surgical findings in operated patients or an appropriate composite clinical reference standard in non-operated patients. Sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy (Acc) were calculated. Inter-reader agreement for MDCT diagnosis was assessed using Cohen’s kappa. Results: For overall mechanical prosthetic valve complications, MDCT showed Se of 82.8%, Sp of 84.6%, PPV of 92.3%, NPV of 68.8%, and Acc of 83.3%. For leaflet obstruction, all diagnostic indices were 100%. For thrombus, Se and Sp were 100% and 96.9%, respectively; for pannus, they were 92.9% and 100%, respectively; Acc was 97.6% for both. In an exploratory analysis with etiologic groups defined by the reference standard, all isolated thrombi had attenuation <90 HU, whereas 91.7% of isolated pannus lesions had attenuation >145 HU (p<0.001). Thrombus tended to occur earlier after surgery, whereas 91.7% of isolated pannus cases occurred more than 5 years after valve replacement (p<0.001). Among nine patients with comparative data, transesophageal echocardiography identified an etiology in 66.7%, whereas MDCT provided an etiologic classification in all cases; one MDCT classification was discordant with the reference standard. The two MDCT readers agreed in 85.7% of cases, with Cohen’s kappa = 0.71 (95% CI: 0.50–0.92). Conclusion: In this selected cohort with suspected mechanical prosthetic valve complications, MDCT showed promising diagnostic performance and provided complementary information on leaflet motion and the differentiation of thrombus from pannus. CT attenuation and time since valve replacement may support etiologic assessment but should be interpreted together with morphology and clinical findings. MDCT is a useful complementary modality to echocardiography in a multimodality diagnostic approach