Valve strands are strongly associated with systemic embolization: A transesophageal echocardiographic study

OBJECTIVES: We attempted to determine the prevalence of strands on native and prosthetic valves, as detected by transesophageal echocardiography, and to assess the relative risk for systemic emboli associated with these strands. BACKGROUND: Fine threadlike strands, seen on native and prosthetic valves by transesophageal echocardiography, have been implicated in systemic embolization. METHODS: During a 2-year period, 1,559 patients underwent transesophageal echocardiography at our center. Of these, 41 patients had strands and no other identifiable source of systemic emboli. They were matched for age, gender, history of hypertension and history of smoking with a control group of 41 patients without strands who also had no identifiable source of emboli. The risk of embolization in the two groups was compared. RESULTS: Of 1,559 patients studied by transesophageal echocardiography, 86 (5.5%) had strands. Strands were far more common on mitral valves than on aortic valves. Of the patients with strands, 38% had had an event consistent with a systemic embolus, whereas 62% had not. Of 597 patients with an embolic event, 63 (10.6%) had strands, whereas only 23 (2.3%) of 962 patients without emboli had strands. In the case-control study, 33 (83%) of the 41 patients with strands without another source of embolism had emboli compared with only 12 (29%) of the 41 control patients without another source (odds ratio 10.0, 95% confidence interval 3.6 to 27.8, p = 0.00001). CONCLUSIONS: Valvular strands visualized by transesophageal echocardiography are associated with systemic embolization.