Provoked Right-to-Left Shunt in Patent Foramen Ovale Associates With Ischemic Stroke in Posterior Circulation

Trigger factors in patients with a patent foramen ovale-associated stroke: A case-crossover study

BACKGROUND

Patent foramen ovale (PFO) is a congenital anatomical variant which is associated with strokes in young adults. Contrary to vascular risk factors and atherosclerosis, a PFO is present from birth. However, it is completely unknown how an anatomical structure that is already present at birth in a large proportion of the population can convert into a PFO that causes stroke in a few. Recent studies reported a significant association between certain trigger factors and ischemic stroke in young adults. This study aims to investigate these triggers in PFO-associated stroke.

METHODS

The ODYSSEY study, a multicenter prospective cohort study between 2013 and 2021, included patients aged 18-49 years experiencing their first-ever ischemic event. Participants completed a questionnaire about exposure to potential trigger factors. A case-crossover design was used to assess the relative risks (RR) with 95% confidence intervals (95% CI). The primary outcome was the RR of potential trigger factors for PFO-associated stroke.

RESULTS

Overall, 1043 patients completed the questionnaire and had an ischemic stroke, of which 124 patients had a PFO-associated stroke (median age 42.1 years, 45.2% men). For patients with PFO-associated stroke, the RR was 26.0 (95% CI 8.0-128.2) for fever, 24.2 (95% CI 8.5-68.7) for flu-like disease, and 3.31 (95% CI 2.2-5.1) for vigorous exercise.

CONCLUSION

In conclusion, flu-like disease, fever, and vigorous exercise may convert an asymptomatic PFO into a stroke-causing PFO in young adults.

DATA ACCESS STATEMENT

The raw and anonymized data used in this study can be made available to other researchers on request. Written proposals can be addressed to the corresponding author and will be assessed by the ODYSSEY investigators for appropriateness of use, and a data sharing agreement in accordance with Dutch regulations will be put in place before data are shared.

Recent progress in patent foramen ovale and related neurological diseases: A narrative review

Patent foramen ovale (PFO) is a common congenital cardiac abnormality when the opening of the interatrial septum is not closed in adulthood. This abnormality affects 25% of the general population. With the development of precision medicine, an increasing number of clinical studies have reported that PFO is closely related to various neurological diseases such as stroke, migraine, obstructive sleep apnea, and decompression syndrome. It has also been suggested that PFO closure could be effective for preventing and treating these neurological diseases. Therefore, increasing attention has been given to the prevention, diagnosis, and treatment of PFO-related neurological diseases. By reviewing existing literature, this article focuses on the pathogenesis, epidemiology, and clinical characteristics of PFO-related neurological diseases, as well as the prevention and treatment of different neurological diseases to discuss, and aims to provide current progress for this field and decision-making evidence for clinical practice.

Simultaneous monitoring of the middle cerebral and basilar arteries to detect right-to-left shunts using transcranial Doppler by agitated saline administration

Transcranial Doppler (TCD) is an easy, non-invasive, and real-time monitoring device for detecting right-to-left shunts (RLS). Nonetheless, it has limited benefits in patients with poor temporal windows. Therefore, we aimed to investigate whether the basilar artery (BA) window was as effective as the middle cerebral artery (MCA) in detecting RLS during TCD monitoring. Overall, we enrolled 344 patients with stroke, transient ischemic attack, headache, or dizziness. MCA and BA were monitored using a modified headset. To investigate the feasibility of the suboccipital window in detecting RLS, we instituted an evaluation tool with three tiers to evaluate microembolic signals (MESs) during TCD monitoring. Tier 1: TCD monitoring of the MCA (bilaterally) in the resting state, tier 2: TCD monitoring of the MCA (bilaterally) while performing the Valsalva maneuver, and tier 3: TCD monitoring of the index MCA and BA while performing the Valsalva maneuver. In tiers 2 and 3, a high agreement rate of 0.808 and 0.809 (p < 0.001), respectively, on the weighted kappa index, and a high intra-class correlation coefficient of 0.982 and 0.986 (p < 0.001), respectively, were observed on detecting MESs. Our data suggests that the BA window is as effective as the MCA window for detecting RLS on TCD.

Evaluation of right-to-left shunt on contrast-enhanced transcranial Doppler in patent foramen ovale-related cryptogenic stroke: Research based on imaging

BACKGROUND

Cardiogenic embolism caused by patent foramen ovale (PFO) is a common etiology of cryptogenic stroke (CS), particularly in young and middle-aged patients. Studies about right-to-left shunt (RLS) detection using contrast-enhanced transcranial Doppler (c-TCD) are numerous. According to the time phase and number of microbubbles detected on c-TCD, RLS can be classified and graded. We hypothesized that the characteristics of an infarction lesion on diffusion-weighted imaging differs when combining the type and grade of RLS on c-TCD in patients with PFO-related CS.

AIM

To explore the characteristics of infarction lesions on diffusion-weighted imaging when combining the RLS type and grade determined by c-TCD.

METHODS

We retrospectively evaluated CS patients from August 2015 to December 2019 at a tertiary hospital. In total, 111 PFO-related CS patients were divided according to whether RLS was permanent (microbubbles detected both at resting state and after the Valsalva maneuver) or latent (microbubbles detected only after the Valsalva maneuver) on c-TCD. Each group was subdivided into small, mild and large RLS according to the grade of shunt on c-TCD. A normal control group was composed of 33 patients who suffered from simple dizziness. Intragroup and intergroup differences were analyzed in terms of clinical, laboratory and diffusion-weighted imaging lesion characteristics. The correlation between RLS grade evaluated by c-TCD and size of PFO determined by transesophageal echocardiography were also analyzed.

RESULTS

In 111 patients with PFO-related CS, 68 had permanent RLS and 43 had latent RLS. Clinical characteristics and laboratory tests were not significantly different among the permanent RLS, latent RLS and normal control groups. The proportion of patients with multiple territory lesions in the permanent RLS group (50%) was larger than that in the latent RLS group (27.91%; P = 0.021). Posterior circulation was more likely to be affected in the latent RLS group than in the permanent RLS group (30.23% vs 8.82%, P = 0.004). Permanent-large and latent-large RLS were both more likely to be related to multiple (P_trend = 0.017 and 0.009, respectively), small (P_trend = 0.035 and 0.006, respectively) and cortical (P_trend = 0.031 and 0.033, respectively) lesions. The grade of RLS evaluated by c-TCD was correlated to the size of PFO determined by transesophageal echocardiography (r = 0.758, P < 0.001).

CONCLUSION

Distribution of the infarct suggested the possible type of RLS. Multiple, small and cortical infarcts suggest large RLS induced by a large PFO.

Comparison of clinical and biological differences between patent foramen ovale subtypes in ischemic stroke

BACKGROUNDS

The patent foramen ovale (PFO) is an atrial septal tunnel with a flap-like opening, causing a right-to-left shunt (RLS) between the atrial chambers. There are few studies on ischemic stroke characteristics based on PFO subtypes. In this study, we investigated whether there are differences in clinical characteristics, RLS amount, and the etiology of stroke defined by the Trial of ORG 10,172 in Acute Stroke Treatment (TOAST) classification between PFO subtypes.

METHODS

We retrospectively analyzed consecutive ischemic stroke patients with PFO who were admitted to the Jeonbuk National University Hospital from November 2013 to February 2015, and performed a microbubble test to detect RLS. The patients were divided into two groups according to RLS characteristics: constant RLS group and provoked RLS group. We compared the clinical characteristics and degree of RLS between the PFO subtypes.

RESULTS

Out of 144 ischemic patients evaluated in this study, 83 (58%) were classified into the constant RLS group and 61 (42%) into the provoked RLS group. The proportion of microembolic signal (MES) grades 3 and 4 was significantly higher in the constant RLS group than in the provoked RLS group. There were no statistical differences in the distribution of TOAST classification between the two groups.

CONCLUSION

The constant RLS group showed a higher proportion of high-grade MES than the provoked RLS group.

Impact of Patent Foramen Ovale Anatomic Features on Right-to-Left Shunt in Patients with Cryptogenic Stroke

The purpose of this study was to investigate the impact of the morphologic characteristics of patent foramen ovale (PFO) on right-to-left shunt (RLS) in patients with PFO and cryptogenic stroke using transesophageal echocardiography and saline contrast transthoracic echocardiography (c-TTE). Of the 165 patients with PFO stroke, both the height and the length of PFO in the provoked RLS group were smaller than those in the constant RLS group. PFO height, interatrial septum mobility and proportion of atrial septal aneurysms were greater in the severe RLS group than in the mild and moderate RLS groups. Multivariate analysis revealed that PFO height and interatrial septum mobility were independent predictors of severe RLS. Multiple territorial ischemic lesions were more common in the severe RLS or constant RLS group. Our findings indicated that the severity of RLS was related to the anatomic features in PFO, inducing different cerebral ischemia lesion patterns in cryptogenic stroke patients with PFO.

Effect of right-to-left shunt on youth benign paroxysmal positional vertigo: A prospective clinical study

OBJECTIVE

To evaluate the correlation between right to left shunt (RLS) and youth benign paroxysmal positional vertigo (YBPPV).

PATIENTS AND METHODS

Patients with benign paroxysmal positional vertigo (BPPV) and normal control cases younger than 45 years were enrolled at 1:1 ratio. Contrast-enhanced transcranial doppler ultrasound was performed to determine the existence and shunt grading of RLS. Regression analysis was conducted by including other possible risk factors for YBPPV to evaluate whether RLS acts as an independent risk factor.

RESULTS

A total of 174 cases were enrolled, with 87 cases in the YBPPV group and 87 cases in the normal control group. The proportion of existing RLS in the YBPPV group was significantly higher than in the normal control group (65.52% vs. 28.74%, P < 0.001). Regression analysis showed that RLS was an independent risk factor for YBPPV (odds ratio = 2.157, 95% credibility interval: 1.504～3.093, P＜0.001). In the YBPPV group, the recurrence of BPPV within 180 days showed no statistical difference between cases with RLS and receiving anti-platelet treatment and cases with RLS and without anti-platelet treatment. In the YBPPV group, the recurrence of BPPV within 180 days in cases without RLS and anti-platelet treatment did not significantly differ from cases with RLS and without anti-platelet treatment and cases with RLS and receiving anti-platelet treatment.

CONCLUSION

In the present study, RLS resulted as an independent risk factor for YBPPV. This observation could generate hypotheses of the mechanism by which a RLS could induce YBPPV.

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).

Relationship between non-headache symptoms and right to left shunt in episodic migraine. A single-center cross-sectional study

The relationship between right to left shunt (RLS) and non-headache symptoms (NHS) in episodic migraine is unknown. This study aimed to investigate the incidence and classification of RLS in episodic migraineurs, calculate the occurrence rate of NHS, and analyze the associations between RLS and NHS. We consecutively recruited 204 episodic migraine patients. Contrast-enhanced transcranial doppler was adopted to screen RLS. Structured questionnaire via face-to-face survey was conducted to collect clinical data. A total of 172 episodic migraineurs were included in the final analysis, of which 20 cases were migraine with aura. The positive rate of RLS was 47.1%, of which 50 cases (29.0%) had small shunt (Grade 1) and 31 cases (18.1%) had mid-large shunt (Grade 2-4). The most common NHS was nausea (115 (66.9%)), followed by headache aggravation with physical activity (96 (55.8%)), dizziness (93 (54.1%)), vomiting (77 (44.8%)) and phonophobia (74 (43.0%)). Yawning was more common in Grade 2-4 group than Grade 0 group (p = 0.012), while no statistical differences among other groups. Grade 2-4 group had a higher rate of headache aggravation with physical activity than grade 0 group (p = 0.008). Binary logistic regression analysis showed that yawning at premonitory phase, headache aggravation with physical activity and cranial autonomic symptoms during attack are independent predictors of RLS. In conclusion, yawning and headache aggravation with physical activity are more common in migraine patients with RLS. Besides aura, particular NHS may also serve as indicators for screening RLS in episodic migraineurs.

Clinical RoPE (cRoPE) score predicts patent foramen ovale detection among stroke patients: a multicenter observational study

BACKGROUD

The role of patent foramen ovale (PFO) in cryptogenic stroke (CS) is debated. Tools to predict PFO occurrence and attributable fraction are needed to guide cost-effective diagnostics and treatment. Risk of Paradoxical Embolism (RoPE) score relies on neuroimaging findings, which might be inconclusive in up to 30% of cases.

METHODS

We developed a clinical-based easy tool to predict the presence and attributable fraction of PFO in CS patients, without using neuroimaging. The clinical RoPE (cRoPE) score, ranging 1-10, was elaborated through Delphi method from the original RoPE score, replacing cortical infarction with the Oxfordshire Community Stroke Project (OCSP) classification (lacunar stroke = 0 points, other subtypes = 1 point). Then, from the SISIFO (Studio Italiano di prevalenza nello Stroke Ischemico di pervietà del Forame Ovale, or Prevalence of Patent Foramen Ovale in Ischemic Stroke in Italy) study, a multicenter, prospective study on consecutive acute ischemic stroke patients (n = 1130) classified by Trial of Org 10172 in Acute Stroke Treatment (TOAST) and OCSP criteria and undergoing PFO testing, we selected the VV-CDC cohort (Vibo Valentia, Città di Castello, n = 323) to test the accuracy of cRoPE in predicting PFO detection. We compared cRoPE with RoPE to verify cRoPE reliability. Finally, we tested, through ROC analysis, the performance of cRoPE depending on TOAST classification.

RESULTS

Overall, PFO was detected in 21% in VV-CDC and in 23.4% in remaining SISIFO cohort (n = 807). cRoPE_AUC and RoPE_AUC were similar in VV-CDC. cRoPE performance was comparable with RoPE among CS (cRoPE_AUC 0.76, 95%CI 0.67-0.85, RoPE_AUC 0.75, 95%CI 0.66-0.84). Moving to the remaining SISIFO cohort, cRoPE confirmed satisfactory accuracy in predicting PFO detection in CS patients (cRoPE_AUC 0.71, 95%CI 0.66-0.78, p = 0.032).

CONCLUSIONS

Conclusions: cRoPE might help in stratification of patients with CS, allowing accurate esteem of the likelihood of PFO to be found, especially in cases when neuroimaging is inconclusive.

Epidemiology of Patent Foramen Ovale in General Population and in Stroke Patients: A Narrative Review

Introduction: Percutaneous closure of patent foramen ovale (PFO) in selected patients with cryptogenic cerebrovascular ischemic events (CEs) decreases the risk of recurrent stroke; however, optimal patient selection criteria are still under investigation. Candidates for PFO closure are usually selected from the pool of CE patients with a high risk of Paradoxical Embolism (RoPE) score. The RoPE score calculates the probability that PFO is causally related to stroke, based on PFO prevalence in patients with CE compared with that in healthy subjects. The latter has been set at 25% based on the average of autopsy and transesophageal echocardiography (TEE) studies.

Methods: We conducted a comprehensive review of studies investigating PFO prevalence in general population and in patients with CE and non-CE using autopsy, TEE, transcranial Doppler (TCD) or transthoracic echocardiography (TTE). Studies were excluded if they (1) reported data from referred subjects with underlying cerebrovascular disease or (2) did not specify etiologically the events.

Results: In healthy/control subjects, PFO prevalence was 24.2% (1,872/7,747) in autopsy studies, 23.7% (325/1,369) in TEE, 31.3% (111/355) in TCD, and 14.7% (186/1,267) in TTE studies. All diagnostic modalities included PFO prevalence was higher in CE compared with healthy/control population [odds ratio (OR) = 3.1, 95% confidence interval (CI) = 2.5–3.8] and compared with non-CE (OR = 2.3, 95% CI = 2.0–2.6). In patients with CE, PFO prevalence in the young compared to the old was higher when the diagnostic modality was TEE (48.9 vs. 27.3%, p < 0.0001, OR = 2.6 with 95% CI = 2.0–3.3) or TCD (58.1 vs. 41%, OR = 1.9, 95% CI = 1.6–2.5), but not TTE (53.3 vs. 37.5%, p = 0.16). Regarding non-CE, PFO prevalence in the young compared to the old was higher when the diagnostic modality was TEE (20 vs. 12.9%, OR = 1.7, 95% CI = 1.0–2.8) but not TTE (10.4 vs. 7.8%, p = 0.75) or TCD (22.8 vs. 20.1%, p = 0.56).

Conclusions: Given the limitations of autopsy and TEE studies, there is good reason not to take a fixed 25% PFO prevalence for granted. The estimation of degree of causality may be underestimated or overestimated in populations with PFO prevalence significantly lower or higher than the established. Given the high sensitivity, non-invasive nature, low cost, and repeatability of TCD, future large-scale TCD-based studies should investigate potential heterogeneity in PFO prevalence in different healthy racial/ethnic populations.

Cough maneuver is superior to Valsalva maneuver for detecting mild-extent right-to-left shunt

Objective: The purpose of this study was to explore the different provocative maneuvers in detecting right-to-left shunt during contrast transthoracic echocardiography (cTTE). Methods: We evaluated 378 patients for right-to-left shunt detection by cTTE at the quiet respiration, during Valsalva maneuver (blowing into a face mask connected to a sphygmomanometer at 40 mmHg for 10 s), and during cough maneuver, performed in random order, and the degree of right-to-left shunt as the number of microbubbles in the left atrium per frame after each provocative maneuver was recorded. Results: The detection rates of right-to-left shunt for quiet respiration, Valsalva maneuver, and cough maneuver were 16%, 33%, and 38%, respectively (p < .001). The detection rate for cough maneuver was significantly higher than that for Valsalva maneuver (p < .001). There was no significant difference between Valsalva maneuver and cough maneuver in terms of detecting moderate- or severe-extent right-to-left shunt (p > .05), but cough maneuver was significantly better than Valsalva maneuver at detecting mild-extent right-to-left shunt (p = .001). Conclusions: Cough maneuver is an effective alternative to Valsalva maneuver, with a higher detection rate for mild-extent right-to-left shunt during cTTE, maybe due to its own mechanical characteristics.

High Incidence of Atrial Fibrillation After Embolic Stroke of Undetermined Source in Posterior Cerebral Artery Territory

Background

Subclinical atrial fibrillation is one possible cause of embolic stroke of undetermined source (ESUS). It remains to be elucidated if a specific infarction site has a predictive value for detecting subclinical atrial fibrillation. We aimed to investigate the predictive value of infarction site in patients with ESUS for the detection of atrial tachyarrhythmia (AT) using an insertable cardiac monitor.

Methods and Results

Consecutive 146 patients (84 men; aged 62±12 years) underwent insertable cardiac monitor implantation after diagnosis of ESUS. The detection of AT >30 seconds was evaluated. The ESUS infarction sites were categorized into internal carotid artery and vertebral artery (VA) territories, with ophthalmic artery, anterior cerebral artery, and middle cerebral artery as internal carotid artery subterritories, and posterior cerebral artery and other vertebrobasilar arteries as VA subterritories. During a median follow‐up of 387 days, AT was detected in 33 patients (23%). Subclinical AT detection was significantly more frequent after VA territorial infarction opposed to internal carotid artery infarction (20/57 [35%] versus 13/89 [15%]; P=0.0039). Kaplan‐Meier analysis demonstrated a significantly higher AT detection rate after VA infarction (log‐rank, P=0.0076). Regression analysis revealed that VA territorial infarction, and particularly posterior cerebral artery area infarction, was an independent predictor of AT detection.

Conclusions

Patients with ESUS in the posterior cerebral artery territory had a higher rate of subclinical AT detection than those with other infarct localizations. Our data suggest that the possible usefulness of ESUS site to identify candidates for direct oral anticoagulation should be confirmed in future research.

Right-to-left shunt detection using contrast-enhanced transcranial Doppler: A comparison of provocation maneuvers between coughing and a modified Valsalva maneuver

Contrast-enhanced transcranial Doppler (c-TCD) has been used to detect right-to-left shunts (RLS) because it is highly sensitive and cost-effective. The use of provocation maneuvers, such as physiologic maneuvers (e.g., coughing) and the Valsalva maneuver (VM) to transiently increase right atrial pressure and induce RLS increases the sensitivity of RLS detection. In this study, we sought to determine whether coughing is as effective as the VM in aiding the detection of RLS. We evaluated 162 subjects for RLS, using c-TCD under three different conditions: (i) resting state, (ii) coughing, and (iii) modified VM (m-VM), which involved blowing into a tube connected to a sphygmomanometer at 40 mmHg for 10 s. The positive rate of RLS detection with the m-VM was significantly higher than that with coughing. In addition, a difference between the two maneuvers was observed in terms of the degree of RLS seen. The m-VM should be widely used to detect RLS, because it is reliable, standardized, and cost-effective.

Posterior versus Anterior Circulation Stroke in Young Adults: A Comparative Study of Stroke Aetiologies and Risk Factors in Stroke among Young Fabry Patients (sifap1)

BACKGROUND

Although 20-30% of all strokes occur in the posterior circulation, few studies have explored the characteristics of patients with strokes in the posterior compared to the anterior circulation so far. Especially data on young patients is missing.

METHODS

In this secondary analysis of data of the prospective multi-centre European sifap1 study that investigated stroke and transient ischemic attack (TIA) patients aged 18-55 years, we compared vascular risk factors, stroke aetiology, presence of white matter hyperintensities (WMH) and cerebral microbleeds (CMB) between patients with ischaemic posterior circulation stroke (PCS) and those having suffered from anterior circulation stroke (ACS) based on cerebral MRI.

RESULTS

We diagnosed PCS in 612 patients (29.1%, 407 men, 205 women) and ACS in 1,489 patients (70.9%). Their age (median 46 vs. 47 years, p = 0.205) and stroke severity (modified Rankin Scale: both 2, p = 0.375, Barthel Index 90 vs. 85, p = 0.412) were similar. PCS was found to be more frequent among the male gender (66.5 vs. 60.1% with ACS, p = 0.003). Vertebral artery (VA) dissection was more often the cause of PCS (16.8%) than was carotid artery dissection of ACS (7.9%, p < 0.001). Likewise, small vessel disease (Trial of Org 10172 in Acute Stroke Treatment [TOAST] = 3, PCS: 14.7%, ACS: 11.8%) and stroke of other determined aetiology (TOAST = 4, PCS: 24.5%, ACS: 16.0%) were more frequent in those with PCS. Furthermore, patent foramen ovale (PFO; PCS: 31.1%, ACS: 25.4%, p = 0.029) was more often detected in patients with PCS. In contrast, large-artery atherosclerosis (TOAST = 1, PCS: 15.4%, ACS: 22.2%) and cardio-embolic stroke (TOAST = 2, PCS: 15.6%, ACS: 18.0%) were less frequent in those with PCS (p < 0.001) as were preceding cerebrovascular events (10.1 vs. 14.1%, p = 0.014), TIA (4.8 vs. 7.7%, p = 0.016) and smoking (53.2 vs. 61.0%, p = 0.001). The presence, extent, and location of WMH and CMB did not differ between the 2 groups.

CONCLUSIONS

Our data suggested a different pattern of aetiology and risk factors in young patients with PCS compared to those with ACS. These findings especially call for a higher awareness of VA dissection and potentially for more weight of a PFO as a risk factor in young patients with PCS. Clinical trial registration-URL: http://www.clinicaltrials.gov; NCT00414583.

Comparison of Vertebral Artery and Middle Cerebral Artery Monitoring for Right-to-left Shunt Detection by Contrast-enhanced Transcranial Doppler

Contrast-enhanced transcranial Doppler (c-TCD) is a reliable and reproducible method for right-to-left shunt (RLS) detection, with high sensitivity. Monitoring the middle cerebral artery (MCA) is an optimal choice, yet for patients with insufficient temporal bone windows or severe stenosis of carotid arteries, an alternative should be established. The aim of the present study was to further establish whether c-TCD with vertebral artery (VA) monitoring is as effective as MCA monitoring for RLS detection. We evaluated 194 subjects for RLS detection with VA and MCA monitoring simultaneously. There was no significant difference between the positive rates of VA and MCA monitoring for RLS detection. c-TCD with VA monitoring could be an alternative for RLS detection, with high sensitivity and specificity both at rest and during the Valsalva manoeuvre.

Right-to-Left Shunt Does Not Increase the Incidence of Silent Lacunar Infarcts in Patients with Migraine

Right-to-left shunt (RLS) is associated with cryptogenic stroke and migraine. Herein we investigated the relationship between RLS and silent lacunar infarcts in patients with migraine. A total of 263 patients with migraine who met eligibility criteria were enrolled from January 2010 to December 2011, among which 127 subjects fell into RLS group. Baseline demographics were comparable between RLS and non-RLS groups (P > 0.05). The incidence of silent lacunar infarcts in RLS group was not significantly different from that of the non-RLS group (25.2% versus 21.3%, P > 0.05). Furthermore, we found that the incidence of silent lacunar infarcts in permanent and latent RLS subgroups was comparable with non-shunt RLS subgroup (28.6% versus 24% versus 21.3%, P > 0.05). Similarly, the incidence of silent lacunar infarcts in the non-RLS group, mild-shunt group, and large-shunt group was also comparable (21.3% versus 23.8% versus 29.3%, P > 0.05). In addition, RLS did not increase the incidence of silent lacunar infarcts in migraine patients with elder age (<50 years age group: 15.8% versus 17.9%; ≥50 years age group: 53.1% versus 37.5%, both P > 0.05). In conclusion, RLS does not increase the incidence of silent lacunar infarcts in patients with migraine. Further prospective studies are warranted to validate this finding.