We hypothesized that microemboli in the basilar artery can be one of the major causes of isolated episodes of vertigo in patients with prosthetic heart valves. In this study, five patients were evaluated for recurrent vertigo after receiving prosthetic heart valves. Vertiginous symptoms associated with vertebrobasilar emboli were characterized by their short duration (within 5 to 30 min), recurrent onset and immediate resolution. HITS were detected in both the middle cerebral artery (MCA) and basilar artery (BA) with a TC-2 64B device (EME Ltd.) or Multi-Dop P (DWL Ltd.) during a 20-min period. Thirty-two patients (control subjects) without vertigo after prosthetic heart valve implantation were also examined by TCD. In the patients with vertigo, the mean HITS rate in the BA was 49.6 ± 18.5/h (range 28 to 72), whereas that in control subjects was 9.8 ± 10.7/h (range 0 to 40, p<0.05) . The mean HITS rate in the MCA was 52.8 ± 29.7/h (range 32 to 104: control; 17.1 ± 14.4, 0 to 56, p<0.05) . The vertiginous patients were then administered aspirin at 60 to 81 mg/day orally in combination with warfarin. In all patients, the vertigo attacks disappeared within 2 to 6 days, and the mean HITS rate in the BA decreased significantly to 8.4 ± 7.3/h (range 0 to 20, p<0.05) . In the MCA, the mean HITS rate was also decreased to 10.4 ± 4.6/h (range 4 to 16, p<0.05) .
In patients with vertigo attacks, who undergo mechanical heart valve placement, TCD examinations could detect HITS in the BA. This may be helpful for the diagnosis and prevention of cerebrovascular accidents in the posterior circulation.
