Characteristic localization patterns of thrombus on various brands of bileaflet mitral mechanical heart valves as assessed by three-dimensional transesophageal echocardiography and their relationship with thromboembolism

Three-dimensional transesophageal echocardiography (3D-TEE) provides detailed images of prosthetic valve thrombosis (PVT). However, data regarding PVT localization patterns based on 3D-TEE and their association with clinical findings among various bileaflet mitral prosthetic valve brands is lacking. The locations of thrombi were classified into 4 groups according to hinge and annulus involvement based on 3D-TEE: ring-like PVT involving entire mitral annulus (type-1), PVT involving peri-hinge(s) region and extends through some part of the annulus (type-2), PVT involving mitral annulus without involving hinge(s) region (type-3), and PVT involving only (peri)hinge(s) area (type-4). This study was conducted in 265 patients (male: 71, mean age: 46.3 ± 12.7 years) with mitral PVT, including 150 St Jude Medical (SJM), 65 Carbomedics, 29 Medtronic ATS open-pivot, and 21 Sorin bileaflet mechanical valves. There was a significant difference in most common PVT localization patterns between different prosthetic valves (type-1 for Carbomedics and Sorin; type-2 for SJM and type-3 for ATS valves; p < 0.001). Additionally, PVT involving only (peri)hinge region(s) (type-4) was mostly observed in patients with SJM valves (18%). (Peri)hinge(s) area involvement was observed in the majority of study patients (78.1%). In patients who presented with thromboembolism, the most common PVT localization pattern was type-1 (53%). Increased age, low international normalized ratio on admission, PVT with a mobile part > 2 mm, type-1 and type-4 PVT were associated with thromboembolic events. In conclusion, thrombus can be displayed in distinct locations in several types of bileaflet mechanical valves due to different design, hinge and pivot mechanisms, which can be complicated with thromboembolic events.