Clinical Investigation
Patent Foramen Ovale
Importance of Adequately Performed Valsalva Maneuver to Detect Patent Foramen Ovale during Transesophageal Echocardiography

https://doi.org/10.1016/j.echo.2013.07.016Get rights and content

Background

Transesophageal echocardiography (TEE) plays an important role in evaluating cardioembolic sources of emboli. The identification of a patent foramen ovale (PFO) is reportedly improved with TEE compared with transthoracic echocardiography (TTE), but the Valsalva maneuver during TEE may be difficult or suboptimal. The aim of this study was to assess the efficacy of the Valsalva maneuver for PFO diagnosis using TEE compared with TTE by evaluating patients with ischemic stroke referred for echocardiography.

Methods

Only patients able to perform the Valsalva maneuver during TTE were included; efficacy was defined by a 20 cm/sec decrease in transmitral E velocity. A PFO was judged present when microbubbles of agitated intravenous saline were seen in the left chambers within three cycles after right atrial opacification.

Results

Of 108 patients (mean age, 55 ± 15 years; 61 men), 48 (44%) were judged to have PFOs by TEE and/or TTE. In 36 patients (33% of the total, 75% of those with PFOs), microbubbles were observed both by TEE and TTE, in seven patients only during TTE, and in five patients only during TEE. In patients able to satisfactorily perform the Valsalva maneuver during TEE, 22 PFOs were found, and two shunts (9%) were missed, whereas in patients unable to perform this maneuver, 26 PFOs were observed, with five shunts missed (19%) (P < .05). When a PFO was missed by TTE, either the echocardiographic window was suboptimal or the shunt was small.

Conclusions

An adequate Valsalva maneuver is crucial for diagnosis of PFO; most patients with stroke may be screened using TTE with contrast and the Valsalva maneuver, with TEE indicated in case of suboptimal transthoracic images.

Section snippets

Patients

The study population consisted of all patients with clinical diagnoses of ischemic CVA at our hospital between December 2009 and January 2011. Specifically, we included patients aged >18 years, of both sexes, referred from the neurology clinic with clinical diagnoses of recent (<7 days) ischemic CVA confirmed by brain computed tomography or magnetic resonance. Exclusion criteria were obvious potential cardioembolic sources (atrial fibrillation, mitral stenosis, and intracardiac thrombus).

Results

Of 117 patients who underwent TEE for the purpose of evaluation of a cardioembolic source of CVA, 108 were included in the protocol. Five patients were not able to perform the Valsalva maneuver because of neurologic disability and were excluded from the study. One patient with left ventricular apical akinesia with a thrombus and three others with atrial fibrillation were also excluded. None of the patients were excluded because of poor transthoracic imaging quality. More contrast injections

Discussion

The prevalence of PFO is relatively common in the general population, at approximately 27% in autopsy studies.11 The clinical significance of PFO in patients with stroke, however, remains unclear, with population-based studies failing to confirm PFO as an independent risk factor for stroke.12 On the other hand, the apparent association between cryptogenic stroke and PFO, mainly in young patients,4, 13 and the association between systemic emboli and PFO14, 15 suggests that paradoxical embolism

Conclusion

The presence of a PFO may be adequately assessed in most patients by contrast TTE, provided that an adequate Valsalva maneuver is performed. TEE improves the diagnosis of PFO in those with suboptimal transthoracic echocardiographic image quality and those with very small shunts. Thus, in the presence of TTE negative for PFO, TEE should be considered in patients with stroke when transthoracic echocardiographic images are suboptimal, suspicion for PFO remains high, or other findings must be

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