Background and purpose: The inter-relation between the size of patent foramen ovale (PFO) by transesophageal echocardiography (TEE) and the amount of microembolic signals (MES) on transcranial doppler (TCD) is still not determined.
Methods: The study group comprised of 104 patients with first-ever ischaemic stroke or transient ischemic attack (TIA). Three groups were formed according to the amount of MES on TCD: a small amount of MES (0-10 MES); a moderate amount of MES (countable MES higher than 10); and multiple MES.
Results: According to TEE, there were 52 patients (50%) with a small PFO, 37 patients (35.6%) with a moderate PFO, and 15 patients (14.4%) with a large PFO. There were 48 patients (46.1%) with a small amount of MES, 34 patients (32.7%) with a moderate amount of MES, and 22 patients (21.1%) with multiple MES on TCD. A strong relationship between the size of the PFO on TEE and the amount of MES on contrast transcranial Doppler was found (P < 0.0001), such that the larger the PFO on TEE, the greater the amount of MES on TCD.
Conclusions: There is a high correlation between the size of the PFO on TEE and the amount of MES on TCD in stroke and TIA patients.