title: Transthoracic second harmonic two- and three-dimensional echocardiography for detection of patent foramen ovale.
abstract: OBJECTIVE
  Transoesophageal echocardiography (TEE) with contrast administration is still considered as the reference method for the detection of patent foramen ovale (PFO) with interatrial shunt, but it is a semi-invasive exam. The aim of the present study is to evaluate a role of two- and three-dimensional transthoracic echocardiography (TTE and R3DTE) as a diagnostic alternative to transcranial Doppler ultrasound (TCD) and TEE for detection of atrial right-to-left shunt.
  
  
  RESULTS
  Seventy-five patients with history of cerebrovascular events were subjected to four diagnostic examinations: TCD, TTE, R3DTE, and TEE, with bubble contrast. Bubbles in the left atrium within three cardiac cycles were considered diagnostic for PFO and later as a pulmonary shunt. Greater than 20 bubbles in the left atrium were considered a large shunt and <20 a small shunt. Every exam was read blinded to the results of the others. From the 75 enrolled patients, 62 (82.6%) patients showed right-to-left shunt with TEE; the results were also positive in 53 patients using TCD (70.6%), in 53 using R3DTE (70.6%), and in 55 using TTE (73.3%) (P = NS). There is a statistically significant superiority for TEE in the capacity of detecting shunts compared with TCD (P < 0.024), TTE (P < 0.018), and R3DTE (P < 0.018). The TEE presents a superior ability to recognize mild/moderate interatrial shunts respect to other exams (P = 0.003), without differences for shunts of high degree. In comparison to the TEE, the sensitivity is 89% for TTE, 88% for R3DTE, and 85% for TCD; the specificity is 100% for TTE and R3DTE, and 90% for TCD; the positive predictive value is 100% for TTE and R3DTE, and 98% for TCD; and the negative predictive value is 65% for TTE, 65% for R3DTE, and 53% for TCD. Considering only for mild/moderate shunts, the diagnostic accuracy is clearly inferior (sensitivity 63% for TTE, 58% for R3DTE, and 53% for TCD).
  
  
  CONCLUSIONS
  In this cohort of patients, TEE confirms the role of 'gold standard' exam for the detection of PFO; the non-invasive methods, and the TTE in particular, present a good diagnostic accuracy, but are inferior to the TEE because of the low negative predictive value and the non-optimal detection of small shunts. If the only purpose of TEE is the detection of significative interatrial shunt, TEE can be replaced by TTE. The R3DTE presents a good diagnostic accuracy, provides a better anatomical definition of the interatrial septum, and may have a role in this setting of patients, but does not add a lot to the TTE for the diagnosis.
authors.affiliation: Division of Cardiology, SS Trinità Borgomanero Hospital, ASL No-Novara, Italy. stemaffe@libero.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Maffè
authors.forename: Pierfranco
authors.initials: P
authors.lastname: Dellavesa
authors.forename: Franco
authors.initials: F
authors.lastname: Zenone
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Paino
authors.forename: Paola
authors.initials: P
authors.lastname: Paffoni
authors.forename: Antonello
authors.initials: A
authors.lastname: Perucca
authors.forename: Daniela
authors.initials: D
authors.lastname: Kozel
authors.forename: Fabiana
authors.initials: F
authors.lastname: Signorotti
authors.forename: Massimo
authors.initials: M
authors.lastname: Bielli
authors.forename: Umberto
authors.initials: U
authors.lastname: Parravicini
authors.forename: Nicolò Franchetti
authors.initials: NF
authors.lastname: Pardo
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cucchi
authors.forename: Alain Guillaime
authors.initials: AG
authors.lastname: Aymele
authors.forename: Marco
authors.initials: M
authors.lastname: Zanetta
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004452:Echocardiography; D019560:Echocardiography, Three-Dimensional; D017548:Echocardiography, Transesophageal; D005240:Feasibility Studies; D005260:Female; D054092:Foramen Ovale, Patent / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology; D018608:Ultrasonography, Doppler; D017585:Ultrasonography, Doppler, Transcranial