Countable and non-countable microembolic signals by TCD in first-ever stroke or TIA patients with PFO.

BACKGROUND

There are data in the literature indicating that the number of microembolic signals (MES) in patients with patent foramen ovale (PFO) is directly related to stroke incidence and recurrence. We thus hypothesized that the amount of artificially induced microembolic signals monitored by contrast transcranial Doppler (cTCD) would be greater in younger patients with PFO and stroke (when cryptogenic strokes related to the PFO are frequent).

PATIENTS AND METHODS

The final analysis included 109 patients with first-ever ischemic stroke or TIA with PFO, as detected by Transesophageal Echocardiography (TEE), and MES, as measured by cTCD. Thirty-seven patients (aged 19-45 years) were defined as the "younger" group, and the other 72 patients (aged 46-77 years) were defined as the "older" group. Eighty-six patients (78.9%) suffered from stroke, including 28 in the younger group and 58 in the older group. The pattern of microembolization was defined as "countable" when the observers were able to calculate the number of MES. In the case of a "shower" of MES on TCD examination, the pattern of monitoring was defined as "non-countable."

RESULTS

Ischemic heart disease, and hyperlipidemia were found to be significantly more frequent in the group of older patients. Twenty-three patients (62.2%) in the younger group had cryptogenic stroke or TIA (no risk factors found), as compared to 26 patients (36.1%) in the older group (p=0.009). There were 23 patients with a non-countable pattern of MES in the older group, as compared with 5 such patients in the younger group (p=0.04). There was no difference found in the number of MES between the groups in those patients with a countable pattern of MES (13.3+/-11.8 in the younger group vs. 13.7+/-11.7 in the older group).

CONCLUSIONS

In stroke and TIA patients above 45 years of age, PFOs producing a large amount of MES on TCD examination are frequent. Thus, there is no correlation between a large amount of MES and stroke or TIA in young patients.