Controlled Contrast Transcranial Doppler and Arterial Blood Gas Analysis to Quantify Shunt Through Patent Foramen Ovale (original) (raw)
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JACC: Cardiovascular Imaging, 2010
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). B A C K G R O U N D 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.
ROLE OF TRANSCRANIAL DOPPLER FOR ASSESSMENT OF PERSISTENT FORAMEN OVALE IN PATIENTS WITH STROKE
Knowledge International Journal, 30(4), 757 - 759., 2019
Transcranial Doppler (TCD) is a noninvasive, portable easy-to perform and easy to interprettechnique for evaluating the intracranial vasculature. The indications for a TCD ultrasound examination of adults include detection of right-to-left shunts (RLS)..The prevalence of a patent foramen ovale (PFO) in the general population is ≈25-30%. Thrombus, formed in the venous systemcould cross the interatrial septum via PFO and provoke paradoxical embolism. The aim of our study was to select those patients, diagnosed with embolic stroke with undetermined etiology (ESUS), who are at higher risk for paradoxical embolism. Materials and methods: During one year a total of 21 consecutive patients (14 male and 7 female) with ESUS were directed to cardiology department for further evaluation. They underwent cTCD for detection of RLS. Results: In part of the patients another risk factors were found. The most commonly encountered stroke was in vertebro-basilar system and in left middle cerebral artery territory. RLS was detected in 12 patients-3 females and 9 males. The medium RoPE score in patients with significant RLS was 6.5. Four patients with RoPE score ≥ 8 were scheduled for PFO closure and the procedure was performed without any complications. Conclusion: TCD is a reliable non-invasive technique to identify ESUS patients with risk for paradoxical embolism. Keywords: Transcranial Doppler, patient foramen ovale, stroke INTRODUCTION Ischemic stroke occurs as a result of obstruction of the brain arteries. Approximately 25% of all ischemic strokes are of undetermined etiology [1]. They are classified as embolic stroke with unknown source (ESUS). The potential embolic sources include those with minor risk as mitral and aortic valve calcification, covert atrial fibrillation, cancer-associated, atherogenic emboli and paradoxical embolism, mostly by PFO [2]. Paradoxical embolism is identified as a cause 4,5-5% of strokes [3,4]. The most common reason for RLS is the patient foramen ovale.The prevalence of a patent foramen ovale (PFO) in the general population is ≈25-30% [5,6]. The vast majority of these people have no problems, due to this condition. Rarely thrombus, formed in the venous system or the right atrium could cross the interatrial septum via PFO and provoke paradoxical embolism-stroke or peripheral embolization [7]. The proven methods to detect RLS are contrast transthoracic echocardiography (c-TTE), contrast transesophageal echocardiography (c-TTE) and contrast transcranial Doppler ultrasonography (c-TCD) (al, 2002). Transcranial Doppler (TCD) is a noninvasive, portable technique for evaluating the intracranial vasculature. The latter is easy-to perform and easy to interpret, low-cost technique, which allows a semiquantitative estimation of venous-to arterial circulation shunts.The data for efficacy of PFO closure for stroke prevention has been uncertain.The randomized clinical trials (RCTs) before 2017 failed to demonstrate that the closure of PFO reduces the risk of subsequent stroke [10-12].Two new trials, published in 2017 [13,14], one in 2018 [15] and one follow-up [16] proved that PFO closure was superior to medical therapy in stroke prevention [17]. The aim of our study was to select those patients, diagnosed with embolic stroke with undetermined etiology (ESUS), who are at risk for paradoxical embolism.
American Journal of Cardiology, 2001
P atent foramen ovale (PFO) is being increasingly recognized as a mediator of paradoxical embolism. 1-3 Transthoracic echocardiography (TTE) with contrast injection has been used frequently for the noninvasive diagnosis of PFO. 4 -6 However, its diagnostic accuracy appears limited, especially in patients with a poor acoustic window. Transesophageal echocardiography with contrast injection has been shown to be more sensitive than TTE, 7-11 and is currently considered to be the gold standard for establishing the presence of PFO. However, transesophageal echocardiography has the disadvantage of semi-invasiveness and may be difficult to perform in stroke patients with swallowing dysfunction or poor cooperation. Harmonic imaging (HI) is a new echocardiographic technique that differs from conventional fundamental imaging (FI) by transmitting ultrasound at 1 frequency and receiving at twice the transmitted frequency. Because HI can enhance the definition of contrast microbubbles, theoretical advantages of HI for the detection of PFO can be considered. However, there are few data regarding the clinical use of HI for the detection of PFO. We hypothesized that transthoracic HI may enhance the detection rate of right-to-left shunt through PFO compared with FI.
Journal of Stroke and Cerebrovascular Diseases, 2009
Background: Patent foramen ovale (PFO) has been investigated in several conditions apart from cryptogenic ischemic stroke. Contrast transesophageal echocardiography (cTEE) is the gold standard for the diagnosis, although it has some known limitations. Contrast transcranial Doppler (cTCD) allows a semiquantitative estimation of right-toleft shunt (RLS) volume. The aims of our study were to confirm the diagnostic accuracy of cTCD in PFO diagnosis and to compare the abilities of cTCD and cTEE to detect a RLS and PFO, respectively, under normal breathing. The latter could represent an important feature for its clinical significance. Methods: A total of 100 consecutive patients (59 women and 41 men, age 46 6 12 years) were evaluated after stabilized ischemic stroke/transient ischemic attack, migraine, and lacunae, and before neurosurgery in sitting position. All patients undertook cTEE and cTCD, at rest and under Valsalva maneuver (VM). cTEE under VM was the reference standard. A categorization of patients and a semiquantitative cTCD classification were proposed. Results: In all, 63 of 100 patients had PFO diagnosed by cTEE. A general concordance of up to 90% between both techniques was found. cTCD sensitivity and specificity were 96.8% and 78.4%, respectively. In 17 of 100 patients with cTEE-proven PFO under VM, cTCD and cTEE detected RLS at rest in 75% (95% confidence interval [CI] 62%-85%) and 48% (95% CI 35%-61%) of cases, respectively (P , .001). cTEE disclosed RLS at rest in about 71% (95% CI 9%-42%) of cTCDs showing a ''shower-curtain'' pattern and only in about 22% (95% CI 52%-85%) of those cTCDs without that pattern. Conclusions: In diagnosing PFO, cTCD has a good accuracy compared with cTEE. To detect a RLS at rest, cTCD appears to be more sensitive than cTEE. The latter resulted positive under normal breathing, mostly in cases of significant RLS at cTCD. Our results point out the impact of cTCD in the evaluation of RLS volume, thus aiding, in association with the anatomic details by cTEE, in the prevention of the occurrence or recurrence of paradoxical embolism in individuals with and without cerebrovascular diseases. The combination of cTEE and cTCD could be considered the real gold standard for PFO in the near future.
Journal of Neuroimaging, 2006
Background and Purpose. Transesophageal echocardiography (TEE) and transcranial Doppler (TCD) are the methods of choice to study patent foramen ovale (PFO), but there are discrepancies between the 2 concerning PFO detection. No study has analyzed right-to-left shunt (RLS) quantification concordance. The 2 methods are carried out in different hemodynamic states, and the Valsalva maneuver (VM) required in each also differs. The authors compared PFO detection and concordance of RLS quantification classifications performing the 2 studies simultaneously. Methods. The authors prospectively included consecutive stroke patients undergoing TEE and applied the TCD protocol of the Consensus Conference. Echocardiographic PFO was diagnosed when at least 3 microbubbles (MBs) were detected in the left atrium within 3 heartbeats after opacification of the right atrium. RLS quantification was (1) TCD: minimum (1-10 MBs), moderate (11-25 MBs), and massive (>25 MBs) and (2) TEE: small (3-10 MBs), moderate (11-30 MBs), and large (>30 MBs). Statistics: contingency tables (χ 2 and K test). Results. The authors studied 110 patients whose mean age was 56.7 ± 12.1 years, and 60.9% were men. PFO was detected at the first VM in 30% of patients with TCD and in 31.8% with TEE. At the second VM, both methods detected the same patients (32.7%). RLS was minimum (14), moderate (5), and massive in TCD and small (13), moderate (3), and large (20) in TEE. There was an almost perfect concordance in RLS quantification (K = 0.928, P = .001), with only 4 discrepancies.
Accuracy of Transcranial Doppler for the Diagnosis of Intracardiac Right-to-Left Shunt
JACC: Cardiovascular Imaging, 2014
The aim of this meta-analysis was to determine the accuracy of transcranial Doppler (TCD) compared with transesophageal echocardiography (TEE) as the reference. B AC K G R O U N D Right-to-left shunting (RLS), usually through a patent foramen ovale (PFO), has been associated with migraine, cryptogenic stroke, and hypoxemia. With emerging observational studies and clinical trials on the subject of PFO, there is a need for accurate diagnosis of PFO in patients with these conditions, and those being considered for transcatheter closure. Although a TEE bubble study is the current standard reference for diagnosing PFO, the TCD bubble study may be a preferable alternative test for RLS because of its high sensitivity and specificity, noninvasive nature, and low cost. M E T H O D S A systematic review of Medline, the Cochrane Library, and Embase was done to look for all the prospective studies assessing intracardiac RLS using TCD compared with TEE as the reference; both tests were performed with a contrast agent and a maneuver to provoke RLS in all studies. R E S U LT S A total of 27 studies (29 comparisons) with 1,968 patients (mean age 47.8 AE 5.7 years; 51% male) fulfilled the inclusion criteria. The weighted mean sensitivity and specificity for TCD were 97% and 93%, respectively. Likewise, the positive and negative likelihood ratios were 13.51 and 0.04, respectively. When 10 microbubbles was used as the embolic cutoff for a positive TCD study, TCD produced a higher specificity compared with when 1 microbubble was used as the cutoff (p ¼ 0.04); there was, however, no significant change in sensitivity (p ¼ 0.29). C O N C L U S I O N S TCD is a reliable, noninvasive test with excellent diagnostic accuracies, making it a proficient test for detecting RLS. TCD can be used as a part of the stroke workup and for patients being considered for PFO closure. If knowledge of the precise anatomy is required, then TEE can be obtained before scheduling a patient for transcatheter PFO closure.
American Heart Journal, 1996
This study investigated whether there is an association between the degree of interatrial shunting across a patent foramen ovale, as determined by saline contrast transesophageal echocardiography, and the risk of subsequent systemic embolic events, including stroke. Thirty-four patients found to have patent foramen ovale during transesophageal echocardiography were divided into two groups on the basis of the maximum number of microbubbles in the left heart in any single frame after intravenous saline contrast injection: group 1 (n = 16) with a "large" degree of shunt (_>20 microbubbles) and group 2 (n = 18) with a "small" degree of shunt (->3 but <20 microbubbles). Patients were followed up over a mean period of 21 months for subsequent systemic embolic events, including transient ischemic attack and stroke. Five (31%) of the patients with large shunts had subsequent ischemic neurologic events, whereas none of the patients with small shunts had embolic events (p = 0.03). These events occurred in spite of antiplatelet or anticoagulant therapy. We conclude that patients with a large degree of shunt across a patent foramen ovale, as determined by contrast transesophageal echocardiography, are at a significantly higher risk for subsequent adverse neurologic events compared with patients with a small degree of shunt.
Arquivos de Neuro-Psiquiatria, 2021
Background: Patent foramen ovale (PFO) has been considered a potential mechanism of embolic stroke of undetermined origin. Objective: The aim of the present study was to identify the features of the right-to-left shunt (RLS) in patients with undetermined embolic ischemic stroke and compare them with those of patients with non-cardioembolic ischemic stroke. Methods: A retrospective study was conducted with 168 patients with stroke and RLS separated into the following two groups: the undetermined embolic stroke group (UES group) and non-cardioembolic stroke group (NCES group). All patients were assessed by transcranial Doppler to evaluate the presence and quantification of microembolic signals (MES) at rest and under Valsalva maneuver. Results: Of all patients evaluated in the current study, 96 were included in the UES group and 72 in the NCES group. In the UES group, 65 patients had RLS with ≥10 MES (67.7%), which was higher than that observed in the NCES group (51.4%, p=0.038). Acco...