Transcranial Doppler for patent foramen ovale screening: is there a good correlation with transesophageal echocardiography?

Abstract

-Right-to-left shunt (RLS) can be identified by contrast-enhanced transcranial Doppler (cTCD) in patent foramen ovale (PFO) patients. Aim: To evaluate cTCD for PFO screening comparing it to cTEE. Method: 45 previous cTCD performed for PFO diagnosis and correlated its findings with cTEE. Patients were submitted to a cTCD standardized technique and were divided in two groups according to RLS: Group 1, patients with a positive RLS and Group 2 when RLS was negative. Results: 29 (65%) patients were included in group 1 and 16 (35%) in group 2. PFO confirmation by cTEE was performed in 28 (62%) patients. cTCD had a 92.85% sensitivity, 82.35% specificity, 89.65% positive predictive value and 87.5% negative predictive value when compared to cTEE for PFO diagnosis. Conclusion: Standardized technique cTCD allows for RLS visualization in PFO patients with a good correlation with cTEE and can be used as a screening test before cTEE.KEy wORDS: patent foramen ovale, transesophageal echocardiography, transcranial Doppler, ultrasonography. Doppler transcraniano contrastado para triagem de forame oval patente: existe boa correlação com ecocardiograma transesofágico?Resumo -A comunicação direita-esquerda (CDE) pode ser identificada por Doppler transcraniano contrastado (DTCc) em pacientes com forame oval patente (FOP Patent foramen ovale (PFO) is a congenital heart disease characterized by an opening between the right and left atria resulting from incomplete closure of the ostium secundum by the septum secundum 1 . Recent studies have found an increase prevalence of PFO in women with migraine with aura and young adults (less than 55 years old) with so-called "cryptogenic" ischemic stroke [2][3][4][5][6] . Emboli from the venous system can cross the PFO reaching the arterial circulation through a right-to-left shunt (RLS) and thus leading to a stroke. PFO diagnosis is done by using a contrast-enhanced technique (by injecting saline solution in a peripheral vein) while performing a transesophageal echocardiography (cTEE) and, when positive, it shows a high correlation with necropsy studies 7 . In spite of both high sensibility and specificity, cTEE have some limitations, such as expensiveness, patient's low tolerability and imperfect intra and inter-observer correlation, due to the fact that it is an operator-dependent method 8 . A great ad-

Is the patent foramen ovale closure the best option?

“…Consequently, this has led to an increase in the number of procedures performed worldwide and the emergence of different devices 2,3,5,6,8,9,16 . Despite these promising results, some cautious recommendations for PFO closure criteria have been recently established.…”

“…The flap of the foramen ovale (septum primum) closes against the atrial septum (septum secundum) and normally fuses within the first two years of life. If the septum secundum covers the oval foramen, but does not seal to the septum primum, then a probable PFO exists that can be "opened" by the Valsalva or other maneuvers that increase right atrial pressure 1,2 . Prevalence of incomplete fusion is approximately 25-27% 1,3 and is associated with atrial septum aneurysm (ASA) in 50-80% patients in a global population 3 .…”

“…Prevalence of incomplete fusion is approximately 25-27% 1,3 and is associated with atrial septum aneurysm (ASA) in 50-80% patients in a global population 3 . The opening between the left and right atria can introduce venous blood or venous thrombus to the arterial system by crossing into the left heart through a right-to-left shunt (RLS) [1][2][3][4][5] . Studies have demonstrated that RLS emboli and PFO are significantly associated with cryptogenic ischemic stroke, transient ischemic attack (TIA) and migraine with aura in young adults (below 55 years of age) [2][3][4][5] .…”

“…Patients with negative or mild microbubble (MB) were classified as negative, and patients moderate or "curtain" were classified as positive 2 . A total of 20 patients were analyzed, with a mean age of 43 years (11-67 years), 12 of whom were females (62,5%).…”

“…The opening between the left and right atria can introduce venous blood or venous thrombus to the arterial system by crossing into the left heart through a right-to-left shunt (RLS) [1][2][3][4][5] . Studies have demonstrated that RLS emboli and PFO are significantly associated with cryptogenic ischemic stroke, transient ischemic attack (TIA) and migraine with aura in young adults (below 55 years of age) [2][3][4][5] . Prevention against further embolic events by PFO closure is a controversial issue, however the procedure is indicated in some restricted cases [6][7][8][9][10][11][12][13] .…”