Prevalence of microembolic signals in patients with different types of mono-leaflet and bi-leaflet prosthetic heart valves.

Microembolic signals (MES) have been described in patients with different types of prosthetic valves. The aim of our study was to compare prevalence of MES in patients with mono-leaflet and bi-leaflet valves, and to correlate them with different clinical and echocardiographic parameters. We evaluated 42 patients, 15 with mono-leaflet and 27 with bi-leaflet valves, with 30-minute bilateral simultaneous transcranial Doppler monitoring for the identification of MES. All patients performed blood testing for international normalized ratio (INR), color-coded duplex of supra-aortic vessels, and echocardiography. Eighteen patients (43%) showed MES; 61% of MES were detected bilaterally, 17% only on the left and 22% only on the right middle cerebral artery (MCA), with no interhemispheric difference. MES did not correlate with patient's age, echocardiographic parameters, INR, presence of atrial fibrillation, or site of valve replacement. One (7%) of the 15 patients with mono-leaflet valves had MES, as opposed to 17 (63%) of the 27 with bileaflet valves (p=0.0003). Patients with bileaflet valves and MES had valves of older implantation and, only for aortic valves, larger valve size.