Sensitivity of Transcranial Doppler Versus Intracardiac Echocardiography in the Detection of Right-to-Left Shunt

Division of Cardiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA.
JACC. Cardiovascular imaging (Impact Factor: 7.19). 04/2010; 3(4):343-8. DOI: 10.1016/j.jcmg.2009.12.012
Source: PubMed


The purpose of this study was to understand the reason for variation in the sensitivity of different methods of detecting right-to-left shunts (RLS).
Patent foramen ovale (PFO) is implicated in the pathogenesis of cryptogenic stroke, decompression illness, and migraine headaches. Intravenous agitated saline injections with tomographic imaging (transthoracic, transesophageal, and intracardiac echocardiography) has been used for detecting intracardiac shunts. Some patients with a high clinical suspicion of PFO have inconclusive echocardiographic study results. Transcranial Doppler (TCD) is an alternative method for detecting RLS that is not dependent on tomographic imaging.
Thirty-eight consecutive patients who were undergoing PFO closure had simultaneous transcranial Doppler and intracardiac echocardiography performed. Agitated saline injections were performed at rest, with Valsalva maneuver, and with forced expiration into a manometer to 40 mm Hg before and after closure, as well as 3 or more months after closure. Right atrial pressures were measured in the periprocedural period, and RLS were graded according to standard methods during these maneuvers.
Right atrial pressures were significantly higher with Valsalva maneuver compared with rest (before closure 21.6 +/- 11.9 mm Hg vs. 6.6 +/- 2.6 mm Hg, p < 0.001; after closure 28.4 +/- 13.9 mm Hg vs. 6.8 +/- 2.6 mm Hg, p < 0.001) and with manometer compared with Valsalva maneuver (before closure 38.7 +/- 6.6 mm Hg vs. 21.6 +/- 11.9 mm Hg, p < 0.001; after closure 44.0 +/- 9.5 mm Hg vs. 28.4 +/- 13.9 mm Hg, p < 0.001). Intracardiac echocardiography underestimated shunting in 34% of patients with Valsalva maneuver or manometer after closure compared with TCD.
Transcranial Doppler with immediate feedback provided by forced expiration against a manometer to 40 mm Hg is more sensitive than echocardiographic imaging for the detection of RLS. These observations have significant implications for determining the incidence of RLS in patients with stroke or migraine.

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    • "The aim of this study was to evaluate the feasibility of transcranial Doppler and its diagnostic sensitivity compared with transesophageal echocardiography. Although the diagnostic power of TCD has been reported, only a few studies comparing both techniques (TCD and TEE) have been published [5,30-33]. In our study TCD had a good sensitivity and specificity. "
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    ABSTRACT: Background: Persistent foramen ovale (PFO) is considered a cause of cryptogenic stroke and a risk factor for neurological events in young patients. The reference standard for identifying a PFO is contrast-enhanced transesophageal echocardiography (TEE).The goal of this study was to evaluate the feasibility of transcranial color Doppler (TCD) and its diagnostic sensitivity compared with TEE. Methods: We investigated 420 patients admitted to our department with cryptogenic stroke, transient ischemic attacks or other neurological symptoms. All patients underwent TCD and TEE evaluation. TCD and TEE examinations were performed according to a standardized procedure: air-mixed saline was injected into the right antecubital vein three times, while the Doppler signal was recorded during the Valsalva maneuver. During TCD the passage of contrast into the right-middle cerebral artery was recorded 25 seconds following the Valsalva maneuver. Results: We detected a right-to-left shunt in 220 patients (52.3%) and no-shunts in 159 patients (37.9%) with both TCD and TEE. In 20 (4.8%) patients TEE did not reveal contrast passage which was then detected by TCD. In 21 (5.0%) patients only TEE revealed a PFO. The feasibility of both methods was 100%. TCD had a sensitivity of 95% and a specificity of 92% in the diagnosis of PFO. Conclusions: TCD has a relatively good sensitivity and specificity. TCD and TEE are complementary diagnostic tests for PFO, but TCD should be recommended as the first choice for screening because of its simplicity, non-invasive character, low cost and high feasibility.
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    • "Cervical vessel ultrasound disclosed neither carotid nor vertebral stenosis nor atherosclerotic changes. Transcranial Doppler showed patency of major cerebral arteries, and saline IV infusion detected a right-to-left at-rest grade III shunt according to the Spencer grading scale (16–50 microembolic signals) [11], with an uncountable number of microembolic signals (shower effect, grade V+) after a Valsalva maneuver. Transesophageal echocardiogram showed a PFO and an interatrial septum protruding to the right atrium 10 mm beyond the original position of the interatrial septum. "
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    ABSTRACT: Spinal cord infarction (SCI) is an uncommon but important cause of acute myelopathy. Nevertheless, contrary to cerebral stroke, the discussion about paradoxical embolism as a cause of cryptogenic SCI remains dubious. We describe the case of a 24-year-old woman who developed sudden-onset back pain followed by upper limb paralysis. T2-weighted MRI demonstrated hyperintense signal, extending from C5 to D1 with corresponding restricted diffusion on diffusion-weighted MRI and reduction of the apparent diffusion coefficient. Diagnostic workup, including lumbar puncture, showed no changes. Transcranial Doppler showed a right-to-left shunt with an uncountable number of microembolic signals after Valsalva maneuvers, and a patent foramen ovale (PFO) with an atrial septum aneurysm was identified. We discuss the paucity of evidence of right-to-left shunting in spinal diseases compared to cerebral events and the potential role of paradoxical embolism through PFO as a possible mechanism of SCI.
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    • "The modality of performing contrast TCD or TCCS is well standardized in the literature [6]. Recently, an increased sensitivity of TCD agitated blood-saline study for the optimal assessment of a suspect of RLS was reported [7,8]. The increased sensitivity of TCCS or TCD and the minimal invasiveness in comparison with angiography or with the discomfort associated with the TEE suggests that these techniques would be the method of choice to diagnose RLS in the appropriate clinical scenario. "
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