1Central Clinical Laboratories, Shinshu University School of Medicine, 2First Department of Internal Medicine, Shinshu University School of Medicine, 3Second Department of Surgery, Shinshu University School of Medicine, 4Third Department of Internal Medicine, Shinshu University School of Medicine
Right atrial mural thrombus, Severe tricuspid regurgitation, Tricuspid valve replacement
Right atrial (RA) and coronary sinus (CS) mural thrombi were observed in four of seven patients who had undergone tricuspid valve replacement (TVR) surgery to treat severe tricuspid regurgitation by transthoracic two-dimensional echocardiography. These thrombi arose from the RA itself and were not associated with foreign bodies or emboli from systemic vein thrombosis. Echocardiographic examination showed reduction in size of RA after all but one of the patients had undergone surgery. The RA was larger in patients with thrombus formation than in patients without it, however. On the other hand, left ventricular ejection fraction of the two groups did not differ significantly, and atrial fibrillation was present in all patients. Thrombi in the RA and CS persisted for a long period of time without remarkable morphologic changes. Further, thrombi disappeared in two of the four patients in the remote phase, when the size of the RA was reduced. These findings suggest that relative stasis of the blood flow in the enlarged RA plays an important role in the formation of primary RA thrombi. The need for more effective surgical reduction in size of the RA in order to prevent thrombus formation in cases of TVR in which there is marked enlargement of the RA must be emphasized.