Prevalence Of Right-to-left Shunt Research Articles

The prevalence of positive right to left shunt in migraine patients with and without aura: A new single-center study in China

BackgroundRecently, many studies have reported that there may be association between positive right-to-left shunt (RLS) and migraine, especially Migraine with aura (MA) patients. However, these researches are mostly limited in Western country. And the latest study describing the prevalence of RLS in Chinese patients with migraine was conducted five years ago. It indicated the significant higher rate of positive RLS in MA patients than migraine without aura(MWOA) group. However, no consistent results were observed according to our daily work. ObjectiveTo investigate the prevalence and grade of RLS in migraine patients with and without aura and to evaluate the potential association between positive RLS and migraine with aura. MethodsA total of 91 migraine patients were involved, including 57 MWOA patients and 34 MA patients. MWOA and MA were diagnosed according to the International Classification of Headache Disorders, 3rd edition (beta version) (ICHD-3). Contrast transcranial Doppler ultra-sound (cTCD) was used to assess the prevalence of positive RLS, the associations between RLS and presence of aura. ResultsThe overall prevalence of RLS in migraine patients was 35.2%.In MA group, 44.1% (15/34) were positive for RLS overall, higher than MWOA group (29.8%,17/57). However, the differences were not significant (P = 0.167). And there were no marked differences in the prevalence of large, middle and small shunt between MA and MWOA patients. ConclusionOur study suggested MA patients have the slightly higher prevalence of positive RLS than MWOA patients in China. However, there were no significant differences, which was different from the previous studies. Our findings suggested the negative association between the positive RLS and migraine with aura.

Cerebral Hemodynamics, Right-to-Left Shunt and White Matter Hyperintensities in Patients with Migraine with Aura, Young Stroke Patients and Controls.

Background: Migraine with aura (MA) patients present an increased risk of cerebrovascular events. However, whether these patients present an increased white matter hyperintensities (WMHs) load compared to the general population is still under debate. Our study aimed to evaluate the relationship between cerebral hemodynamics, right-to-left shunt (RLS) and WMHs in MA patients, young patients with cryptogenic stroke or motor transient ischemic attack (TIA) and controls. Methods: We enrolled 30 MA patients, 20 young (<60 years) patients with cryptogenic stroke/motor TIA, and 10 controls. All the subjects underwent a transcranial Doppler bubble test to detect RLS and cerebral hemodynamics assessed by the breath holding index (BHI) for the middle (MCA) and posterior (PCA) cerebral arteries. Vascular risk factors were collected. The WMHs load on FLAIR MRI sequences was quantitatively assessed. Results: The stroke/TIA patients presented a higher prevalence of RLS (100%) compared with the other groups (p < 0.001). The MA patients presented a higher BHI compared with the other groups in the PCA (p = 0.010) and higher RLS prevalence (60%) than controls (30%) (p < 0.001). The WMHs load did not differ across groups. BHI and RLS were not correlated to the WMHs load in the groups. Conclusions: A preserved or more reactive cerebral hemodynamics and the presence of a RLS are likely not involved in the genesis of WMHs in MA patients. A higher BHI may counteract the risk related to their higher prevalence of RLS. These results need to be confirmed by further studies to be able to effectively identify the protective role of cerebral hemodynamics in the increased RLS frequency in MA patients.

Relationship between right-to-left shunt detected by c-TCD and clinical characteristics in migraine patients

Objectives:To explore the relationship between the presence or parameters of right-to-left shunt (RLS) detected by c-TCD and attack clinical features in migraine patients with aura (MA+) or without aura (MA-).Methods:Migraine patients with aura and migraine patients without aura (MA-) were recruited consecutively. The RLS was assessed by a c-TCD examination.Results:A total of 528 migraine patients and 71 healthy were included. The prevalence of RLS especially of mild shunts was higher in patients with migraine. Patients of MA+ developed migraine earlier and experienced more severe pain, more frequent photophobia and phonophobia, although the yearly frequency, duration and degree of pain or type and size of shunt was similar. Moreover, patients with MA+ and RLS (MA+RLS+) also experienced more photophobia and phonophobia than that without RLS (MA+RLS-). The result was similar in MA-RLS+ group. Patients with moderate or massive of RLS experience longer duration of pain in both MA+RLS+ and MA-RLS+ groups. The sex distribution was only significantly different in MA+RLS+ group, in which women were more likely to suffer from RLS especially mild shunt.Conclusion:A higher prevalence and severity of RLS was found in the migraine patients, especially those with aura. MA+ patients develop earlier and experience more severe pain. The duration was consistent with the shunt size in both MA+RLS+ and MA-RLS+ groups.

Positive Relationship Between Paroxysmal Vertigo and Right-to-Left Shunt: A Large Observational Study.

BackgroundThe association between paroxysmal vertigo and right-to-left shunt (RLS) is rarely reported. This study investigates the prevalence and correlation of RLS in patients with different paroxysmal vertigo diseases.MethodsPatients with paroxysmal vertigo from seven hospitals in China were included in this observational study between 2017 and 2021. Migraine patients within the same period were included for comparison. Demographic data and medical history were collected; contrast transthoracic echocardiography was performed; and the clinical features, Dizziness Handicap Inventory, and incidence of RLS in each group were recorded.ResultsA total of 2,751 patients were enrolled. This study's results demonstrated that the proportion of RLS in patients with benign recurrent vertigo (BRV) and vestibular migraine (VM) was significantly higher than that in patients with benign paroxysmal positional vertigo, Meniere's disease, and vestibular paroxysmia (P < 0.05). No statistical difference was shown between the frequency of RLS in patients with BRV and those with migraine and VM. A positive correlation was shown between the RLS grade and Dizziness Handicap Inventory scores of patients with VM and BRV (P < 0.01) after effectively controlleding the effect of confounding variables.ConclusionsRLS was significantly associated with BRV and VM. RLS may be involved in the pathogeneses of BRV and VM and may serve as a differential reference index for the paroxysmal vertigo.Trial RegistrationCHRS, NCT04939922, registered 14 June 2021- retrospectively registered, https://register.clinicaltrials.gov.

Prevalence and grade of RLS in migraine: A prospective study of 251 migraineurs by synchronous test of c-TTE and c-TCD.

Background:Right-to left shunt (RLS) is regarded as a risk factor resulting in migraine, but the relevance between the RLS and migraine remains controversial. This paper aims at investigating the prevalence and RLS grade of patent foramen ovale (PFO) in cases of migraine (including migraine with and without aura) and evaluate the relationship between PFO and migraine.Methods:Synchronous test of contrast transthoracic echocardiography and contrast transcranial Doppler ultrasonography was performed in 251 cases of migraine, which contains 62 cases of migraine with aura (MA) and 189 cases without aura (MO) and 275 healthy adults. Among these cases, 25 cases with migraine and 14 healthy adults were evaluated through transesophageal echocardiography.Results:(1). The prevalence of permanent RLS, total RLS, and large RLS in migraine was 11.16%, 39.04%, and 17.13%, respectively, which was significantly higher than that of the controls (P = .042, <.001, and.001, respectively). (2). Permanent RLS was detected as 7.93% of the cases in MO, 20.96% in MA, and 6.18% in controls. Total RLS was detected as 35.98% of the cases in MO, 48.38% in MA, and 23.64% in controls. Large RLS was detected as 13.76% of the cases in MO, 27.41% in MA, and 7.27% in controls. Compared with controls, the positive rate of total RLS and large RLS in MO increased (P = .004 and.022, respectively), the that of permanent RLS, total RLS, and large RLS in MA also increased (P < .001 for each of the comparisons). The positive rate of permanent RLS and large RLS in MA was remarkably higher than that in MO (P = .005 and.013, respectively). (3) The presence of large-size PFO (≥2.0 mm) of migraine showed higher than that of the controls (P = .048).Conclusions:PFO is associated with the migraine (especially with aura), when it is permanent RLS, large RLS, and large-size PFO (≥2.0 mm).

Right-to-left shunts in lowlanders with COPD traveling to altitude: a randomized controlled trial with dexamethasone.

Right-to-left shunts (RLS) are prevalent in patients with chronic obstructive pulmonary disease (COPD) and might exaggerate oxygen desaturation, especially at altitude. The aim of this study was to describe the prevalence of RLS in patients with COPD traveling to altitude and the effect of preventive dexamethasone. Lowlanders with COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 1-2, oxygen saturation assessed by pulse oximetry () >92%] were randomized to dexamethasone (4 mg bid) or placebo starting 24 h before ascent from 760 m and while staying at 3,100 m for 48 h. Saline-contrast echocardiography was performed at 760 m and after the first night at altitude. Of 87 patients (81 men, 6 women; mean ± SD age 57 ± 9 yr, forced expiratory volume in 1 s 89 ± 22% pred, 95 ± 2%), 39 were assigned to placebo and 48 to dexamethasone. In the placebo group, 19 patients (49%) had RLS, of which 13 were intracardiac. In the dexamethasone group 23 patients (48%) had RLS, of which 11 were intracardiac (P = 1.0 vs. dexamethasone). Eleven patients receiving placebo and 13 receiving dexamethasone developed new RLS at altitude (P = 0.011 for both changes, P = 0.411 between groups). RLS prevalence at 3,100 m was 30 (77%) in the placebo and 36 (75%) in the dexamethasone group (P = not significant). Development of RLS at altitude could be predicted at lowland by a higher resting pulmonary artery pressure, a lower arterial partial pressure of oxygen, and a greater oxygen desaturation during exercise but not by treatment allocation. Almost half of lowlanders with COPD revealed RLS near sea level, and this proportion significantly increased to about three-fourths when traveling to 3,100 m irrespective of dexamethasone prophylaxis.NEW & NOTEWORTHY The prevalence of intracardiac and intrapulmonary right-to-left shunts (RLS) at altitude in patients with chronic obstructive pulmonary disease (COPD) has not been studied so far. In a large cohort of patients with moderate COPD, our randomized trial showed that the prevalence of RLS increased from 48% at 760 m to 75% at 3,100 m in patients taking placebo. Preventive treatment with dexamethasone did not significantly reduce the altitude-induced recruitment of RLS. Development of RLS at 3,100 m could be predicted at 760 m by a higher resting pulmonary artery pressure and arterial partial pressure of oxygen and a more pronounced oxygen desaturation during exercise. Dexamethasone did not modify the RLS prevalence at 3,100 m.

Prevalence and extent of right-to-left shunt on contrast-enhanced transcranial Doppler in patients with chronic hyperventilation syndrome: results of a case-control study.

Chronic hyperventilation syndrome (CHVS) represents a frequent but poorly understood breathing pattern disorder. In a previous small pilot study, we reported a higher prevalence of right-to-left shunt (RLS) in CHVS patients than in healthy subjects. The aim of this study was to confirm those previous results from this larger and matched case-control study, and to evaluate the prevalence and grade of RLS in patients with CHVS in whom organic and psychiatric causes were excluded. Determining other types of CHVS triggers not related to organic or psychiatric causes which could be clinically useful. 100 subjects (mean age 34 ± 6 years; 80% females), including 50 patients with CHVS and 50 age- and sex-matched healthy controls (CG), were prospectively recruited into this single-centre study. Vascular RLS was diagnosed using contrast-enhanced transcranial Doppler (c-TCD). RLS prevalence significantly increased in the CHVS group (n = 23) compared to the CG group (n = 8) (46% vs 16%; p < 0.01). Patients with CHVS and RLS tended to have more frequent permanent shunts compared to the CG (60% vs 25%; p = 0.08), but there was no difference regarding RLS grading between the groups. This study confirmed our previous findings in which the prevalence of RLS in patients with CHVS was significantly higher than in an age- and sex-matched healthy control group. However, we could not confirm the results of our prior study, where RLS was larger in CHVS than in CG. The tentative association between RLS and CHVS needs to be further examined.

Right-To-Left Shunt and Migraine

Right-to-left shunt (RLS) is an abnormal pathway between the venous and arterial circulations, and includes both intracardiac and extracardiac RLSs. Intracardiac RLSs are usually related to patent foramen ovale (PFO). Contrast-enhanced transcranial Doppler ultrasonography (c-TCD) is a clinically applicable and reproducible method of detecting RLSs. Migraine is a common disabling neurovascular disorder. It has a high prevalence, 7.9%-14% in the western population and 9.3% in the Chinese population. The pathogenesis of migraine is not well understood. Available data suggest that PFO is more common in patients with migraine, whereas other studies have reported that the prevalence of RLS is similar in patients with and without migraine. The aim of the present study was to assess the prevalence and extent of RLS using c-TCD in Chinese patients with migraine and compare them to the prevalence and extent of RLS in healthy controls. We then used these data to evaluate the relationship between RLS and migraine. The main finding was that the prevalence of RLS was significantly higher in Chinese migraineurs than it was in healthy controls. Hence, there appears to be a close relationship between RLS and migraine without aura as well as between RLS and migraine with aura. In addition, the proportion of large shunts was significantly larger in migraineurs with and without aura than it was in healthy controls. It suggested that RLS, especially large RLS, is associated with migraine with aura as well as migraine without aura. RLS may be involved in the pathogenesis of migraine. Detection of right-to-left shunt should be considered in patients with migraine.

Increased prevalence of potential right-to-left shunting in children with sickle cell anaemia and stroke.

'Paradoxical' embolization via intracardiac or intrapulmonary right-to-left shunts (RLS) is an established cause of stroke. Hypercoagulable states and increased right heart pressure, which both occur in sickle cell anaemia (SCA), predispose to paradoxical embolization. We hypothesized that children with SCA and overt stroke (SCA+stroke) have an increased prevalence of potential RLS. We performed contrasted transthoracic echocardiograms on 147 children (aged 2-19years) with SCA+stroke) mean age 12·7±4·8years, 54·4% male) and a control group without SCA or stroke (n=123; mean age 12·1±4·9years, 53·3% male). RLS was defined as any potential RLS detected by any method, including intrapulmonary shunting. Echocardiograms were masked and adjudicated centrally. The prevalence of potential RLS was significantly higher in the SCA+stroke group than controls (45·6% vs. 23·6%, P<0·001). The odds ratio for potential RLS in the SCA+stroke group was 2·7 (95% confidence interval: 1·6-4·6) vs controls. In post hoc analyses, the SCA+stroke group had a higher prevalence of intrapulmonary (23·8% vs. 5·7%, P<0·001) but not intracardiac shunting (21·8% vs. 18·7%, P=0·533). SCA patients with potential RLS were more likely to report headache at stroke onset than those without. Intrapulmonary and intracardiac shunting may be an overlooked, independent and potentially modifiable risk factor for stroke in SCA.

Migraine with aura and patent foramen ovale: myth or reality?

Several observational studies report that subjects with migraine with aura have a higher prevalence of right-to left shunt, commonly due to patent foramen ovale, and that patent foramen ovale is more prevalent in subjects with migraine with aura. Although migraine without aura has been less extensively studied, it does not seem to be associated with an increased prevalence of right-to left shunt. The mechanism that underlies the possible relationship between patent foramen ovale and migraine with aura remains speculative. The proposed mechanisms are migraine-triggering vasoactive chemicals bypassing the pulmonary filter and reaching the cerebral circulation and paradoxical microembolization. However, it is unclear, at this time, if there is a causal or comorbid association between the two conditions. In some families atrial shunts show a dominant inheritance that seems to be linked to inheritance of migraine with aura. Migraine with aura is an independent risk factor for ischemic stroke, and patent foramen ovale is present more frequently in patients with cryptogenic stroke than in controls. At this moment, there is no convincing evidence that excess stroke risk of migraine is simply mediated by patent foramen ovale through paradoxical embolism. Several non-controlled studies suggest that closure of the foramen ovale significantly reduces attack frequency in migraine patient, but the only prospective placebo-controlled trial does not support these results. Patent foramen ovale closure, at present, is not indicated as a treatment for migraine in clinical practice.

Cardiac right‐to‐left shunt subtypes in Chinese patients with cryptogenic strokes: a multicenter case−control study

Data on the possible association between cardiac right-to-left shunt (RLS) and cryptogenic stroke are lacking in Asians. RLS and its subtypes in Chinese cryptogenic stroke patients were investigated. Patients (n=153, mean age 42±10years, 81 male) with cryptogenic stroke from four medical centers in China and 135 healthy volunteers (mean age 34±8years, 54 male) were recruited. Contrast transcranial Doppler was used to assess the prevalence of RLS. A three-level RLS categorization was applied as follows: none, 0 microbubbles (MBs); small, 1-25 MBs; and large, >25 MBs. RLS was considered latent if it occurred only after the Valsalva maneuver or permanent when it occurred also during normal respiration. Overall, RLS (P=0.02), large RLS (P<0.001) and permanent RLS (P=0.02) were more frequently detected in patients with cryptogenic stroke than in healthy volunteers. The prevalences of small RLS and latent RLS in the two groups were similar (22% vs. 21% and 11% vs. 10%, respectively). The proportion of large RLSs amongst the subjects with RLS was much higher in the patient group than in healthy volunteers (45% vs. 18%, P<0.001), whilst the proportion of permanent RLS was similar (72% vs. 64%, P=0.11). Most large RLSs in the patient group (22/27, 81%) were permanent RLSs. Cardiac RLS is associated with cryptogenic stroke in Chinese. However, the higher prevalence of overall RLS in the patient group was mainly due to the increased proportion of large RLSs. The results only support large RLSs as a pathological condition.

Prevalence of right-to-left shunts on transcranial Doppler in chronic migraine and medication-overuse headache

It was suggested that right-to-left shunt (RLS) may be highly prevalent in chronic migraine (CM) patients, indicating that patent foramen ovale (PFO) might be an aggravating and chronifying factor of migraine. Since a high proportion of chronic migraineurs also have medication-overuse headache (MOH), one may wonder if they have a more severe form of the disorder and more frequently a PFO. The objective of this study is to determine the prevalence and grade of RLS in patients suffering from CM and MOH. A cross-sectional multicenter study of air-contrast transcranial Doppler was conducted in 159 patients with CM ( N = 57) or MOH ( N = 102) attending a tertiary headache clinic. The prevalence of RLS in CM was 37% (11% large shunts) and in MOH patients 31% (13% large shunts). There was no difference between the two groups ( P = 0.49). RLS prevalence in CM is within the upper range of those reported in episodic migraine without aura or in the general population, and not higher in MOH. PFO is thus unlikely to have a significant causal role in these chronic headaches.

A right-to-left shunt and prothrombotic disorders in pediatric patients presenting with transient ischemic attack

Arterial ischemic stroke is an important cause of morbidity and mortality in pediatric population. A right-to-left shunt (RLS) across the patent foramen ovale was recently demonstrated as a possible risk factor for pediatric stroke. Prothrombotic disorders are frequently identified in pediatric patients with stroke. Data regarding RLS and prothrombotic disorders in pediatric patients presenting with transient ischemic attack (TIA) are lacking. The aims of the present study were (1) to compare the prevalence and grade of RLS in pediatric patients presenting with TIA vs. controls using contrast transcranial Doppler with Valsalva maneuver and (2) to identify prothrombotic disorders in pediatric patients presenting with TIA. Twenty-three consecutive pediatric patients presenting with TIA were included in the study. Logistic regression analysis showed that RLS was significantly associated with TIA (OR 4.75, 95% CI 1.39-16.2, p = 0.013). The prevalence of RLS was significantly higher in patients in comparison to controls (p = 0.019). Significantly more microembolic signals (MES) were detected in patients than in controls (p = 0.003). Prothrombotic disorders were identified in 14 of the 23 patients. Both the prevalence of RLS and number of detected MES were significantly higher in pediatric patients presenting with TIA in comparison to controls. Prothrombotic disorders were identified in a high proportion of patients. These findings suggest that paradoxical embolism may be important in pediatric patients presenting with TIA.

Inner ear decompression sickness in scuba divers: a review of 115 cases

Inner ear decompression sickness (IEDCS) in scuba divers is increasingly observed, but epidemiological data are limited to small case series and the pathogenesis remains elusive. We report our experience over a 13-year period. We also thought to demonstrate that the development of this injury is mainly attributed to a mechanism of vascular origin. Diving information, clinical data, presence of circulatory right-to-left shunt (RLS), and laboratory investigations of 115 recreational divers were retrospectively analyzed. A follow-up study at 3 months was possible with the last 50 consecutive cases. IEDCS (99 males, 44 ± 11 years) represented 24 % of all the patients treated. The median delay of onset of symptoms after surfacing was 20 min. Violation of decompression procedure was recorded in 3 % while repetitive dives were observed in 33 %. The median time to hyperbaric treatment was 180 min. Pure vestibular disorders were observed in 76.5 %, cochlear deficit in 6 % and combination of symptoms in 17.5 %. Additional skin and neurological disorders were reported in 15 % of cases. In 77 %, a large RLS was detected with a preponderant right-sided lateralization of IEDCS (80 %, P < 0.001). Incomplete recovery was found in 68 % of the followed patients. Time to recompression did not seem to influence the clinical outcome. IEDCS is a common presentation of decompression sickness following an uneventful scuba dive, but the therapeutic response remains poor. The high prevalence of RLS combined with a right-sided predominance of inner ear dysfunction suggests a preferential mechanism of paradoxical arterial gas emboli through a vascular anatomical selectivity.

Paradoxical embolism as a cause of silent brain infarctions in healthy subjects: the ICONS study (Identification of the Cause of Silent Cerebral Infarction in Healthy Subjects)

In healthy elderly people, silent brain infarctions (SBIs) have been recognized as common lesions. In this study, we evaluated the association between SBI located outside the perforating artery territory (PAT) and paradoxical embolism detected by agitated saline transcranial Doppler (TCD) monitoring in healthy subjects. This was a prospective observational study undertaken by a university health promotion center for healthy subjects and by a university stroke center for acute stroke patients. We defined SBI as evidence on fluid-attenuation inversion recovery (FLAIR) magnetic resonance imaging (MRI) of one or more infarcts, without history of corresponding stroke or transient ischaemic attack. We also evaluated in all subjects the neuroimaging indicator of microangiopathy leukoaraiosis (LA). This study is registered with ClinicalTrials.gov, number NCT01429948. Amongst 1103 consecutive healthy adults who underwent MRI, 347 (31%) had one or more SBIs located outside the PAT, suggesting embolism. Amongst them, 253 subjects underwent agitated saline TCD monitoring and 128 (51%) had right-to-left shunts (RLS). The prevalence of RLS was similar to cryptogenic embolic stroke (62.0%, P = 0.056), but higher than in patients with other stroke subtypes (36.2%, P = 0.021). Amongst subjects with SBI, absence of LA was the only factor associated with RLS (OR 1.78; 95% CI 1.01-3.14; P = 0.046). Our results suggest that paradoxical embolism may play an important role in the development of SBI outside the PAT in apparently healthy adults.

Prevalence and extent of right‐to‐left shunt in migraine: a survey of 217 Chinese patients

Recently, contrast-enhanced transcranial Doppler (cTCD) studies have shown that right-to-left shunt (RLS) may be a risk factor for migraine in Westerners; however, limited data in the literature describes the prevalence of RLS in Chinese patients with migraine. To assess the prevalence of RLS in patients with migraine in China and to evaluate the relationship between the extent of RLS and migraine. A total of 217 consecutive patients with a diagnosis of migraine and 100 volunteers were recruited. cTCD was used to assess the prevalence and the extent of RLS in all subjects. In the migraine group, the rate of positive RLS was 44.2% (96/217), with 23.5% (51/217) of these being large. In the healthy group, 28.0% (28/100) were positive for RLS overall, and 5.0% (5/100) were large (P = 0.006; P < 0.001). In patients having migraines with aura (MwA), 66.1% (39/59) were positive for RLS overall, and 37.3% (22/59) were large, which was significantly higher when compared with the healthy group (P < 0.001; P < 0.001); in patients having migraines without aura (MwoA), 36.1% (57/158) were positive for RLS overall, and 18.4% (29/158) were large, which was against significantly higher (P < 0.001; P = 0.003). In the MwoA group, the large RLS rate was also higher than in the healthy group (P = 0.002). A close correlation has been documented between RLS and migraine, especially MwA, but these relationships exist only when the shunts were large.

Right-to-left shunts and micro-embolization in migraine

The present review covers the latest studies on right-to-left shunts (RLSs) in migraine patients and different types of emboli capable of triggering migraine. Although three recent studies found no increased RLS prevalence in migraine with aura patients, there remains ample evidence that the prevalence of RLS is increased in migraine with aura. Introduced emboli in the carotid artery of mice have been shown to cause cortical spreading depression, which has been considered the pathophysiological mechanism of migraine aura. In humans, iatrogenic introduced (micro)-emboli can provoke migraine attacks; available evidence, however, is limited. RLS and migraine with aura (but not without) are comorbid conditions, but the biological mechanism remains speculative. Specific emboli are probably able (although infrequently) to induce migraine symptoms. There is no convincing evidence that closure of a RLS alters migraine frequency; therefore, diagnosis or treatment of RLS in migraine has no place in daily clinical practice and should only take place in controlled studies.

An increased frequency of right-to-left shunt in patients with chronic hyperventilation syndrome

Relation of right-to-left shunt (RLS) with chronic hyperventilation syndrome (CHVS) has not been previously reported. We evaluated the prevalence of RLS in patients with CHVS. Patients with CHVS and 25 healthy controls (CG) were recruited into the study. Vascular RLS was diagnosed using contrast TCD. Of 25 subjects with CHVS, 16 (64%) had RLS vs 3 from CG (12%). TEE confirmed PFO in 10 patients with CHVS (40%) vs 2 from CG (8%). Pulmonary AVM was found in chest CT in 2 patients (10%) with CHVS and none from CG. The prevalence of RLS and PFO in patients with CHVS was significantly higher than in healthy subjects.

A right-to-left shunt in children with arterial ischaemic stroke

ObjectiveTo compare the prevalence and grade of right-to-left shunt (RLS) in children with arterial ischaemic stroke (AIS) and in controls.DesignProspective study.SettingTertiary paediatric referral centre.Patients30 consecutive children with AIS.InterventionContrast transcranial Doppler...

Small deep white matter lesions are associated with right-to-left shunts in migraineurs

The right-to-left shunts (RLS) and white matter lesions (WMLs) are frequently observed in migraineurs and in patients with ischemic stroke. Previous studies have reported that the burden of WMLs did not increase with the intracardiac right-to-left shunt (RLS) in migraineurs. However, some types of WMLs are known to be associated with RLS in patients with stroke and dementia. The aim of the study was to demonstrate the difference in the size and location of WMLs, according to the existence of RLS in patients with headache. From the prospective headache registry, a total of 425 subjects (age, 30.8 ± 5.1 years; 303 women; 242 migraineurs; 183 patients with tension-type headache (TTH)) were retrospectively reviewed and evaluated for RLS and WMLs using M-mode power transcranial Doppler sonography (mTCD) and brain magnetic resonance imaging scans. We scored WMLs, according to the Rotterdam Scan Study, and assessed the association between RLS presence and the location and size of WMLs. The number of small deep WMLs (dWMLs) and the prevalence of RLS, defined as microembolic signals (MES) ≥ 11, were higher in patients with migraine (small dWMLs, 6.23 vs. 4.05; RLS, 36.8% vs. 10.9%), compared to patients with TTH. There was no significant difference in the sum of periventricular WML grades or the total volume of dWMLs between TTH and migraine patients. Among the migraineurs, the patients with RLS more frequently had small dWMLs, aura, and heart disease compared to those without RLS. In addition, RLS were also independent predictors for the presence of small dWMLs from the multivariate binary regression analysis (p < 0.01; OR = 3.24; 95%CI 1.56-6.72). Small dWMLs are associated with RLS in young migraineurs. These results imply that paradoxical embolism may cause the small WMLs in some migraineurs.