Circulating Microemboli in Patients After Aortic Valve Replacement With Pulmonary Autografts and Mechanical Valve Prostheses

Abstract

Background The pulmonary autograft procedure (Ross) is now considered the gold standard for aortic valve replacement. One of its advantages is the freedom from macroemboli without anticoagulation. Whether this holds true for circulating microemboli, detectable as high-intensity transient Doppler signals (HITS), has not yet been verified. Methods and Results We investigated 8 patients (2 women, 6 men; mean age, 50.6±17.9 years) after the Ross procedure, 9 patients (3 women, 6 men; mean age, 67.2±9.46 years) after aortic valve replacement with a mechanical valve prosthesis, and 12 young healthy volunteers by unilateral 1-hour recording of the middle cerebral artery on digital audio tape. Patients with extracranial carotid artery disease were excluded by color duplex sonography. During the off-line evaluation, the investigator was not aware of any patient details. No HITS were detected in healthy volunteers (95% confidence interval [CI], 0% to 26.46%). After the Ross procedure, 1 patient had 11 and 1 patient had 1 HITS (95% CI, 3.19% to 65.09%). All recipients of mechanical valves had HITS, ranging from 2 to 84 per hour (95% CI, 66.7% to 100%). Significantly more recipients of mechanical valves exhibited HITS than recipients of pulmonary autografts ( P <.05) or control subjects ( P <.05). Conclusions In contrast to mechanical valves, pulmonary autografts are seldom the source of microemboli, confirming the pulmonary autograft as the superior substitute for aortic valve replacement.